ORGANIC COMPOUNDS OF THE MONOBACTAM FAMILY FOR THE TREATMENT OF BACTERIAL INFECTIONS

Abstract

This invention relates generally to antibacterial compounds of formula i, as described in the invention, and to pharmaceutically acceptable formulations and salts thereof. In certain aspects, the invention relates to methods of using such compounds to treat infections such as those caused by Gram-negative bacteria.

Description

FIELD OF THE INVENTION

[0001] This invention relates to novel β-lactam compounds, and their preparation and use. In particular, the invention relates to novel β-lactam compounds where the lactam ring is monocyclic, and their uses to treat bacterial infections, especially those caused by Gram-negative bacteria.BACKGROUND

[0002] Over the past several decades, the frequency of antimicrobial resistance and its association with serious infectious diseases have increased at alarming rates. The increasing prevalence of resistance among nosocomial pathogens is particularly disconcerting. Of the over 2 million nosocomial infections occuring each year in the United States, 50 to 60% are caused by antimicrobial-resistant strains of bacteria. The high rate of resistance to commonly used antibacterial agents increases the morbidity, mortality, and costs associated with nosocomial infections. In the United States, nosocomial infections are thought to contribute to or cause more than 77,000 deaths per year and cost approximately $5 to $10 billion annually.

[0003] Important causes of Gram-negative resistance include extended-spectrum β-lactamases (ESBLs), serine carbapenemases (KPCs) and metallo-β-lactamases (for example NDM-1) in Klebsiella pneumoniae, Escherichia coli, and Proteus mirabilis, high-level third-generation cephalosporin (AmpC) β-lactamase resistance among Enterobacter species and Citrobacter freundii, and multidrug-resistance genes observed in Pseudomonas, Acinetobacter, and Stenotrophomonas. The problem of antibacterial resistance is compounded by the existence of bacterial strains resistant to multiple antibacterials. For example, Klebsiella pneumonia harboring NDM-1 metallo-β-lactamase carries frequently additional serine-β-lactamases on the same plasmid that carries the NDM-1.

[0004] Thus there is a need for new antibacterials, particularly antibacterial compounds that are effective against existing drug-resistant microbes, or are less susceptible to development of new bacterial resistance. The current invention provides such compounds.SUMMARY

[0005] The invention includes novel compounds, pharmaceutical formulations including the compounds, and methods of using such compounds and compositions for treatment of patients with bacterial infections. The compounds are monobactams, which comprise a monocyclic beta-lactam ring, and which typically act by inhibition of penicillin-binding proteins (PBPs), which are involved in biosynthesis of peptidoglycans required for normal bacterial cell walls. Some known members of this class include aztreonam and carumonam. Other monobactam compounds are disclosed in EP0093376A2, WO2013 / 110643 and WO2012 / 073138. The compounds are primarily effective against Gram-negative bacteria.

[0006] The compounds of the invention can be used to treat infection caused by Enterobacteriaceae, including Salmonella, E. coli, Klebsiella pneumoniae, Proteus, Enterobacter, Serratia, and Citrobacter, including pathogens such as KPC producing Klebsiella pneumoniae that are less susceptible to previous monobactams like aztreonam, as well as non-fermenting bacteria, including Pseudomonas aeruginosa, Acinetobacter, Burkholderia, Moraxella and Stenotrophomonas.

[0007] The compounds of the invention can be used alone or in combination with other antibiotics, and can be used in combination with compounds such as beta-lactamase inhibitors that potentiate the activity of the compounds of the invention against certain pathogens or reduce the frequency or extent of bacterial resistance to the compounds of the invention against certain pathogens. Suitable beta-lactamase inhibitors for use in combination with the compounds of the invention include avibactam, tazobactam, sulbactam and clavulanic acid.

[0008] In one aspect, the invention provides compounds of Formula (I): or a pharmaceutically acceptable salt thereof, wherein: Z is CR 4< or N; R 1< is H or C 1 -C 4 alkyl; R 2< is selected from the group consisting of H, C 1 -C 4 alkyl, and -COOH or R 1< and R 2< taken together with the carbon to which they are attached form a ring selected from a C 3 -C 6 cycloalkyl ring and a 4-6 membered heterocyclic ring containing up to two heteroatoms selected from N, O and S as ring members; R 3< is selected from H, -COOH, and -L 1< -W-(CH 2 ) 0-2 -X-R 5< ; R 4< is H or halo; each L 1< is independently a straight chain or branched C 1-4 alkylene; W is a bond, O, NH or S; X is phenyl, or a 5-6 membered heteroaryl ring containing 1-3 heteroatoms selected from N, O and S as ring members; where the phenyl and 5-6 membered heteroaryl are optionally substituted with one or two groups selected from C 1-4 alkyl, hydroxy, -CN, F, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) and -N(C 1-4 alkyl) 2 ; R 5< is selected from wherein R 1b< , R 2b< , and R 3b< are independently hydrogen, hydroxy, CN, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member, wherein each (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member may be substituted with one, two or three substituents selected independently from Y, and wherein R 2b< and R 3b< together with the nitrogen atom to which they are bonded can optionally form a 5- to 7-membered heterocyclyl including 0 or 1 further heteroatoms selected from N, O and S, said heterocyclyl optionally substituted by Y; Y is selected from F, CN, -NH 2 , Q, -L 2< -C(O)NR 10< -L 2< -Q, -L 2< -NR 10< -C(O)-L 2< -Q, -L 2< -OR 10< , -L 2< -N(R 10< ) 2 , -L 2< -N +< (R 11< ) 3 , -L 2< -NR 10< -C(O)R 10< , -L 2< -NR 10< -L 2< -N(R 10< ) 2 , -L 2-< O-C(O)OR 10< , -L 2< -O-C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-OR 11< , -L 2< -C(=NR 10< )-N(R 10< ) 2 ,-CON(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-N(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-R 10< , -L 2< -C(O)N(R 10< ) 2 , -L 2< -O-SO 3 R 10< ; L 2< is independently at each occurrence a bond or a straight chain or branched C 1-4 alkylene, optionally substituted with NH 2 , OH, or F; Het is a 4-6 membered saturated heterocyclic ring, where the heterocyclic ring contains 1 or 2 heteroatoms selected from N, O and S as ring members and is substituted with oxo and optionally further substituted with Y; R 10< and R 12< are independently H or C 1-4 alkyl optionally substituted by one or two groups selected from OH, NH 2 or Q; Q is selected from -L 2< -N(R 13< ) 2 , -L 2< -N +< (R 14< ) 3 , -L 2< -NR 13< -C(=NR 13< )-N(R 13< ) 2 , -L 2< -NR 13< -CR 13< (=NR 13< ), -L 2< -NR 13< -L 2< -Cy, -L 2< -NR 13< -C(=NR 13< )-NR 13< -L 2< -Cy, -L 2< -NR 13< -C(=NR 13< )-L 2< -Cy, -L 2< -Cy-L 2< -R 13< , -L 2< -Cy-L 2< -N(R 13< ) 2 , -L 2< -NR 13< -SO 2 N(R 13< ) 2 , -L 2< -SO 2 -N(R 13< ) 2 , -L 2< -NR 13< -SO 2 -R 13< , -L 2< -NR 13< -L 2< -Ar, -L 2< -S-L 2< -Cy , -L 2< -NR 13< -(C=O)-O-R 13< , each Cy is independently a 3-6 membered cycloalkyl or 3-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as a ring member and optionally fused to a 5-6 membered aryl or heteroaryl ring, wherein each Cy is optionally substituted with one or two groups selected from halo, C 1-3 haloalkyl, R 14< , hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; Ar is phenyl, optionally substituted with one or two groups selected from halo, C 1-3 haloalkyl, R 14< , hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; R 11< is independently at each occurrence C 1-4 alkyl; and two R 10< , or two R 11< , or two R 12< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, or oxo; R 13< is independently at each occurrence H or C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; R 14< is independently at each occurrence C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; wherein two R 13< or two R 14< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, amino or oxo; R 15< is H, halo, C 1-4 alkyl, CN, or -O(C 1-4 alkyl); or a pharmaceutically acceptable salt thereof.

[0009] In another aspect, the invention provides a compound of formula (I) for use in a method of inhibiting bacterial growth or modulating the virulence of a bacterial infection.

[0010] In another aspect, the invention provides a compound of formula (I) for use in a method for treating a subject having a Gram-negative bacterial infection, optionally in combination with a pharmaceutically acceptable carrier. In certain embodiments, the subject is a mammal and in some embodiments, the subject is a human.

[0011] The Gram-negative bacteria may be of a genus selected from Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Proteus, Salmonella, Serratia, Pseudomonas, Acinetobacter, Bacteroides, Burkholderia, Campylobacter, Neisseria, and Stenotrophomonas. In particular, a bacterial infection caused by a species of Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Proteus, Salmonella, Serratia, Pseudomonas, or Acinetobacter is treatable. Particular bacterial species for such treatment include Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae, Enterobacter faecalis, Enterobacter faecium, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Morganella morganii, Proteus mirabilis, Salmonella species, Serratia marcescens, Pseudomonas aeruginosa, and Acinetobacter baumanii, as well as Bacteroides bivius, Bacteroides fragilis, Burkholderia cepacia, Campylobacter jejuni, Neisseria gonorrhoeae, and Stenotrophomonas maltophilia.

[0012] In another aspect, the invention provides a compound of formula (I) for use in a method of administering an inhibitory amount of a compound of formula (I) to fermenting or non-fermenting Gram-negative bacteria. In certain embodiments the compound of formula (I) for use in the method of administering an inhibitory amount of a compound of formula (I) to fermenting or non-fermenting Gram-negative bacteria, the Gram-negative bacteria are species of Burkholderia, Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Neisseria, Proteus, Salmonella, Serratia, Pseudomonas, and Acinetobacter. Particular bacterial species for such methods include Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae, Enterobacter faecalis, Enterobacter faecium, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Neisseria meningiditis and Burkholderia cepacia, Morganella morganii, Proteus mirabilis, Salmonella species, Serratia marcescens, Pseudomonas aeruginosa, and Acinetobacter baumanii, as well as Bacteroides bivius, Bacteroides fragilis, Burkholderia cepacia, Campylobacter jejuni, Neisseria gonorrhoeae, and Stenotrophomonas maltophilia.

[0013] In another embodiment, the invention provides a compound of formula (I) for use in a method of administering an inhibitory amount of a compound of formula (I) to Gram-negative bacteria, such as an Enterobacteriaceae; in some embodiments the Gram-negative bacteria is selected from the group consisting of species of Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Proteus, Salmonella, Serratia, Pseudomonas, and Acinetobacter.

[0014] Another embodiment of the invention provides a pharmaceutical composition comprising an effective amount of a compound of Formula (I) combined with a pharmaceutically acceptable carrier or excipient. An 'effective amount' as used here refers to an amount sufficient to reduce the severity or symptoms of an infection, or an amount effective to reduce bacteria load in the patient.

[0015] Pharmaceutical compositions according to the present invention are provided which include any of the compounds described herein and a pharmaceutically acceptable carrier. In some embodiments the composition includes an additional therapeutic agent or a beta lactamase inhibitor.

[0016] In another aspect, the invention provides a pharmaceutical combination comprising a compound of the invention and an additional therapeutic agent or a beta lactamase inhibitor or optionally both.

[0017] The present invention provides novel compounds, compounds for use in methods for inhibiting survival and population growth of Gram-negative bacteria, and compounds for use in novel methods and compositions for treating bacterial infections in mammals, particularly in human subjects. The compounds provided herein can be formulated into pharmaceutical formulations and medicaments that are useful in methods to inhibit bacterial growth or severity or duration of a bacterial infection, or to treat a subject having a bacterial infection that is susceptible to inhibition by the compounds of Formula (I). The invention also provides the compounds for use in preparing medicaments and pharmaceutical formulations, for use in inhibiting bacterial growth, and for use in treating bacterial infections in a subject in need of such treatment, e.g., a subject infected with a Gram-negative bacteria or at especially high risk for such infection.

[0018] Other aspects of the invention are discussed herein.DETAILED DESCRIPTION

[0019] For purposes of interpreting this specification, the following definitions apply unless specified otherwise or clearly contradicted by context. Whenever appropriate, terms used in the singular will also include the plural and vice versa.Definitions

[0020] Terms used in the specification have the following meanings: As used herein, the term "subject" refers to an animal. In certain aspects, the animal is a mammal. A subject also refers to for example, primates (e.g., humans), cows, sheep, goats, horses, dogs, cats, rabbits, rats, mice, fish, birds and the like. In certain embodiments, the subject is a human.

[0021] As used herein, the term "inhibition" or "inhibiting" refers to the reduction or suppression of a given condition, symptom, or disorder, or disease, or a significant decrease in the baseline activity of a biological activity or process, or decrease in the viability, number or growth rate of a bacterial population.

[0022] As used herein, the term "treating" or "treatment" of any disease or disorder refers in one embodiment, to ameliorating the disease or disorder (i.e., slowing or arresting or reducing the development of the disease or at least one of the clinical symptoms thereof). In another embodiment "treating" or "treatment" refers to alleviating or ameliorating at least one physical parameter including those which may not be discernible by the patient. In yet another embodiment, "treating" or "treatment" refers to modulating the disease or disorder, either physically, (e.g., stabilization of a discernible symptom), physiologically, (e.g., stabilization of a physical parameter), or both. In yet another embodiment, "treating" or "treatment" refers to preventing or delaying the onset or development or progression of the disease or disorder.

[0023] As used herein, the term "a," "an," "the" and similar terms used in the context of the present invention (especially in the context of the claims) are to be construed to cover both the singular and plural unless otherwise indicated herein or clearly contradicted by the context.

[0024] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed.

[0025] The term "antibacterial agent" refers to agents synthesized or modified in the laboratory that have either bactericidal or bacteriostatic activity. An "active" agent in this context will inhibit the growth of P. aeruginosa and l or other Gram-negative bacteria. The term "inhibiting the growth" indicates that the rate of increase in the numbers of a population of a particular bacterium is reduced. Thus, the term includes situations in which the bacterial population increases but at a reduced rate, as well as situations where the growth of the population is stopped, as well as situations where the numbers of the bacteria in the population are reduced or the population even eliminated.

[0026] "Optionally substituted" means the group referred to can be substituted at one or more positions by any one or any combination of the radicals listed thereafter. Such substitution involves the replacement of a hydrogen atom of the unsubstituted group with another moiety; thus the number of substituents that can be added to any unsubstituted group is equal to the number of hydrogen atoms on the unsubstituted group. If not otherwise specified, 'optionally substituted' means that up to three non-hydrogen substituent groups can be added.

[0027] "Halo" or "halogen", as used herein, may be fluorine, chlorine, bromine or iodine.

[0028] "C 1 -C 6 alkyl", or "C 1-6 alkyl" as used herein, denotes straight chain or branched alkyl having 1-6 carbon atoms. If a different number of carbon atoms is specified, such as C 8 or C 3 , then the definition is to be interpreted accordingly, such as "C 1 -C 4 alkyl" will include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl.

[0029] "C 1 -C 6 alkoxy", or "C 1-6 alkoxy" as used herein, denotes straight chain or branched alkoxy having 1-6 carbon atoms. If a different number of carbon atoms is specified, such as C 8 or C 3 , then the definition is to be interpreted accordingly, e.g., "C 1 -C 4 alkoxy" will represent methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy.

[0030] "C 1 -C 4 -Haloalkyl" or "C 1-4 haloalkyl" as used herein, denotes straight chain or branched alkyl having 1-4 carbon atoms, wherein at least one hydrogen has been replaced by a halogen. If a different number of carbon atoms is specified, such as C 6 or C 3 , then the definition is to be interpreted accordingly, thus "C 1 -C 4 -Haloalkyl" will represent methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl that have at least one hydrogen substituted with halogen, such as where the halogen is fluorine: CF 3 CF 2 -, (CF 3 ) 2 CH-, CH 3 -CF 2 -, CF 3 CF 2 -, CF 3 , CF 2 H-, CF 3 CF 2 CHCF 3 or CF 3 CF 2 CF 2 CF 2 -.

[0031] "C 3 -C 8 -cycloalkyl" or "C 3-8 cycloalkyl" as used herein refers to a saturated monocyclic hydrocarbon ring of 3 to 8 carbon atoms. Examples of such groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. If a different number of carbon atoms is specified, such as C 3 -C 6 , then the definition is to be interpreted accordingly.

[0032] "4- to 8-Membered heterocyclyl", "5- to 6- membered heterocyclyl", "3- to 10-membered heterocyclyl", "3- to 14-membered heterocyclyl", "4- to 14-membered heterocyclyl" and "5- to 14-membered heterocyclyl", refer, respectively, to 4- to 8-membered, 5- to 6-membered, 3- to 10-membered, 3- to 14-membered, 4- to 14-membered and 5- to 14-membered heterocyclic rings containing 1 to 7, 1 to 5 or 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulphur, which may be saturated, or partially saturated. "Heterocyclic" may be used interchangeably with "heterocyclyl". The heterocyclic group can be attached at a heteroatom or a carbon atom. The term "heterocyclyl" includes single ring groups, fused ring groups and bridged groups. Examples of such heterocyclyl include, but are not limited to pyrrolidine, piperidine, piperazine, oxazolidine, pyrrolidinone, morpholine, tetrahydrofuran, tetrahydrothiophene, tetrahydrothiopyran, tetrahydropyran, 1,4-dioxane, 1,4-oxathiane, 8-aza-bicyclo[3.2.1]octane, 3,8-diazabicyclo[3.2.1]octane, 3-Oxa-8-aza-bicyclo[3.2.1]octane, 8-Oxa-3-aza-bicyclo[3.2.1]octane, 2-Oxa-5-aza-bicyclo[2.2.1]heptane, 2,5-Diaza-bicyclo[2.2.1]heptane, azetidine, ethylenedioxo, oxtane and thiazolidine. Preferably, a heterocyclic or heterocyclyl group is a saturated or partially saturated monocyclic group unless otherwise specified, and contains 5-7 ring atoms with up to two heteroatoms selected from N, O and S as ring members. In some embodiments, a heterocyclic group further includes bicyclic ring systems containing 1 or 2 heteroatoms such as N, O or S as ring members and comprising two fused 3-, 4-, 5-, or 6-membered rings, such as 3-azabicyclo[3.1.0]hexane, 8-aza-bicyclo[3.2.1]octane, 3,8-diazabicyclo[3.2.1]octane, 3-Oxa-8-aza-bicyclo[3.2.1]octane, 8-Oxa-3-aza-bicyclo[3.2.1]octane, 2-Oxa-5-aza-bicyclo[2.2.1]heptane, 2,5-Diaza-bicyclo[2.2.1]heptane.

[0033] "Heteroaryl" is a completely unsaturated (aromatic) ring. The term "heteroaryl" refers to a 5-14 membered monocyclic- or bicyclic- or tricyclic-aromatic ring system, having 1 to 8 heteroatoms selected from N, O and S. Typically, the heteroaryl is a 5-10 membered ring system (e.g., 5-6 membered monocycle or an 8-10 membered bicycle) or a 5-6 membered ring system. Unless otherwise specified, a heteroaryl is preferably an isolated 5-6 membered ring containing up to 4 heteroatoms selected from N, O and S as ring members. Typical heteroaryl groups include furan, isothiazole, thiadiazole, oxadiazole, indazole, indole, quinoline, 2- or 3-thienyl; 2- or 3-furyl; 2- or 3-pyrrolyl; 1-, 2-, 4-, or 5-imidazolyl; 1, 3-, 4-, or 5- pyrazolyl; 2-, 4-, or 5-thiazolyl, 3-, 4-, or 5-isothiazolyl, 2-, 4-, or 5-oxazolyl, 3-, 4-, or 5-isoxazolyl, 3- or 5-(1,2,4-triazolyl), 4- or 5-(1,2, 3-triazolyl), tetrazolyl, triazine, pyrimidine, 2-, 3-, or 4-pyridyl, 3- or 4-pyridazinyl, 3-, 4-, or 5-pyrazinyl, 2-pyrazinyl, and 2-, 4-, or 5-pyrimidinyl.

[0034] The term "hydroxy" or "hydroxyl" refers to the group -OH, or when used as part of a group name such as hydroxyalkyl, it refers to the named group substituted with an -OH. Various embodiments of the invention are described herein. It will be recognized that features specified in each embodiment may be combined with other specified features to provide further embodiments. The following numbered embodiments are representative of some aspects of the invention. 1. A compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein: Z is CR 4< or N; R 1< is H or C 1 -C 4 alkyl; R 2< is selected from the group consisting of H, C 1 -C 4 alkyl, and -COOH or R 1< and R 2< taken together with the carbon to which they are attached form a ring selected from a C 3 -C 6 cycloalkyl ring and a 4-6 membered heterocyclic ring containing up to two heteroatoms selected from N, O and S as ring members; R 3< is selected from H, -COOH, and -L 1< -W-(CH 2 ) 0-2 -X-R 5< ; R 4< is H or halo; each L 1< is independently a straight chain or branched C 1-4 alkylene; W is a bond, O, NH or S; X is phenyl, or a 5-6 membered heteroaryl ring containing 1-3 heteroatoms selected from N, O and S as ring members; where the phenyl and 5-6 membered heteroaryl are optionally substituted with one or two groups selected from C 1-4 alkyl, hydroxy, -CN, F, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) and -N(C 1-4 alkyl) 2 ; R 5< is selected from wherein R 1b< , R 2b< , and R 3b< are independently hydrogen, hydroxy, CN, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member, wherein each (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member may be substituted with one, two or three substituents selected independently from Y, and wherein R 2b< and R 3b< together with the nitrogen atom to which they are bonded can optionally form a 5- to 7-membered heterocyclyl including 0 or 1 further heteroatoms selected from N, O and S, said heterocyclyl optionally substituted by Y; Y is selected from F, CN, -NH 2 , Q, -L 2< -C(O)NR 10< -L 2< -Q, -L 2< -NR 10< -C(O)-L 2< -Q, -L 2< -OR 10< , -L 2< -N(R 10< ) 2 , -L 2< -N +< (R 11< ) 3 , -L 2< -NR 10< -C(O)R 10< , -L 2< -NR 10< -L 2< -N(R 10< ) 2 , -L 2< -O-C(O)OR 10< , -L 2< -O-C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-OR 11< , -L 2< -C(=NR 10< )-N(R 10< ) 2 ,-CON(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-N(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-R 10< , -L 2< -C(O)N(R 10< ) 2 , -L 2< -O-SO 3 R 10< ; L 2< is independently at each occurrence a bond or a straight chain or branched C 1-4 alkylene, optionally substituted with NH 2 , OH, or F; Het is a 4-6 membered saturated heterocyclic ring, where the heterocyclic ring contains 1 or 2 heteroatoms selected from N, O and S as ring members and is substituted with oxo and optionally further substituted with Y; R 10< and R 12< are independently H or C 1-4 alkyl optionally substituted by one or two groups selected from OH, NH 2 or Q; Q is selected from -L 2< -N(R 13< ) 2 , -L 2< -N +< (R 14< ) 3 , -L 2< -NR 13< -C(=NR 13< )-N(R 13< ) 2 , -L 2< -NR 13< -CR 13< (=NR 13< ), -L 2< -NR 13< -L 2< -Cy, -L 2< -NR 13< -C(=NR 13< )-NR 13< -L 2< -Cy, -L 2< -NR 13< -C(=NR 13< )-L 2< -Cy, -L 2< -Cy-L 2< -R 13< , -L 2< -Cy-L 2< -N(R 13< ) 2 , -L 2< -NR 13< -SO 2 -N(R 13< ) 2 , -L 2-< SO 2 -N(R 13< ) 2 , -L 2< -NR 13< -SO 2 R 13< , -L 2< -NR 13< -L 2< -Ar, -L 2< -S-L 2< -Cy , -L 2< -NR 13< -(C=O)-O-R 13< , each Cy is independently a 3-6 membered cycloalkyl or 3-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as a ring member and optionally fused to a 5-6 membered aryl or heteroaryl ring, wherein each Cy is optionally substituted with one or two groups selected from halo, C 1-3 haloalkyl, R 14< , hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; Ar is phenyl, optionally substituted with one or two groups selected from halo, C 1-3 haloalkyl, R 14< , hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; R 11< is independently at each occurrence C 1-4 alkyl; and two R 10< , or two R 11< , or two R 12< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, or oxo; R 13< is independently at each occurrence H or C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or -N(C 1-4 alkyl) 2 ; optionally, when R 13< is C 1-4 alkyl it can be substituted with -OR 14< , -NHR 14< , hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or-N(C 1-4 alkyl) 2 ; R 14< is independently at each occurrence C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or-N(C 1-4 alkyl) 2 ; wherein two R 13< or two R 14< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, amino or oxo; R 15< is H, halo, C 1-4 alkyl, CN, or -O(C 1-4 alkyl); or a pharmaceutically acceptable salt thereof.

[0035] It is understood that each of the compounds in Table B, including compounds of Examples 1-156, is an embodiment of the invention and is intended to fall within the scope of embodiment 1. 2. A compound of Formula (IA): or a pharmaceutically acceptable salt thereof, wherein: Z is CR 4< or N; R 1< is H or C 1 -C 4 alkyl; R 2< is selected from the group consisting of H, C 1 -C 4 alkyl, and -COOH or R 1< and R 2< taken together with the carbon to which they are attached form a ring selected from a C 3 -C 6 cycloalkyl ring and a 4-6 membered heterocyclic ring containing up to two heteroatoms selected from N, O and S as ring members; R 3< is selected from H, -COOH, and -L 1< -W-(CH 2 ) 0-2 -X-R 5< ; R 4< is H or halo; each L 1< is independently a straight chain or branched C 1-4 alkylene; W is a bond, O, NH or S; X is phenyl, or a 5-6 membered heteroaryl ring containing 1-3 heteroatoms selected from N, O and S as ring members; where the phenyl and 5-6 membered heteroaryl are optionally substituted with one or two groups selected from C 1-4 alkyl, hydroxy, -CN, F, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) and -N(C 1-4 alkyl) 2 ; R 5< is selected from wherein R 1b< , R 2b< , and R 3b< are independently hydrogen, hydroxy, CN, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl, wherein each (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, (C 3 -C 6 )cycloalkyl, or 4-, 5-, 6- or 7-membered heterocyclyl may be substituted with one, two or three substituents selected independently from Y, and wherein R 2b< and R 3b< together with the nitrogen atom to which they are bonded can optionally form a 5- to 7-membered heterocyclyl including 0 or 1 further heteroatoms selected from N, O and S, said heterocyclyl optionally substituted by Y; Y is selected from F, CN, -NH 2 , Q, -L 2< -C(O)NR 10< -L 2< -Q, -L 2< -NR 10< -C(O)-L 2< -Q, -L 2< -OR 10< , -L 2< -N(R 10< ) 2 , -L 2< -N +< (R 11< ) 3 , -L 2< -NR 10< -C(O)R 10< , -L 2< -NR 10< -L 2< -N(R 10< ) 2 , -L 2< -O-C(O)OR 10< , -L 2< -O-C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-N(R 10< ) 2 , -L 2< -NR 10< -C(O)-OR 11< , -L 2< -C(=NR 10< )-N(R 10< ) 2 ,-CON(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-N(R 10< ) 2 , -L 2< -NR 10< -C(=NR 10< )-R 10< , -L 2< -C(O)N(R 10< ) 2 , , -L 2< -O-SO 3 R 10< ; L 2< is independently at each occurrence a bond or a straight chain or branched C 1-4 alkylene; Het is a 4-6 membered saturated heterocyclic ring, where the heterocyclic ring contains 1 or 2 heteroatoms selected from N, O and S as ring members and is substituted with oxo and optionally further substituted with Y; R 10< and R 12< are independently H or C 1-4 alkyl optionally substituted by Q; Q is selected from -L 2< -N(R 13< ) 2 , - L 2< -N +< (R 14< ) 3 , -L 2< -NH-C(=NH)-NH 2 , -L 2< -C(=NH)-NH 2 , R 11< is independently at each occurrence C 1-4 alkyl; and two R 10< , or two R 11< , or two R 12< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, or oxo; R 13< is independently at each occurrence H or C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or-N(C 1-4 alkyl) 2 ; R 14< is independently at each occurrence C 1-4 alkyl optionally substituted with hydroxy, C 1-4 alkoxy, -NH 2 , -NH(C 1-4 alkyl) or-N(C 1-4 alkyl) 2 ; wherein two R 13< or two R 14< on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C 1-4 alkyl, C 1-4 alkoxy, hydroxy, amino or oxo; R 15< is H, halo, C 1-4 alkyl, CN, or -O(C 1-4 alkyl); or a pharmaceutically acceptable salt thereof.

[0036] In certain embodiments of the compounds of Formula (I) or (IA), the group represented by -O-CR 1< R 2< R 3< is selected from 3. The compound of embodiment 1 or embodiment 2, wherein R 1< and R 2< are each methyl and R 3< is -COOH. 4. The compound of embodiment 1 or embodiment 2, wherein R 1< and R 2< together with the carbon to which they are both attached form a cyclopropane ring and R 3< is -COOH. 5. The compound of embodiment 1 or embodiment 2, wherein R 1< and R 2< are both H and R 3< is -COOH. 6. The compound of any of the preceding embodiments, wherein Z is CH. 7. The compound of any of embodiments 1-6, wherein Z is N. 8. The compound of any of embodiments 1-7, wherein Het is a saturated ring substituted with oxo and optionally further substituted with Y. 9. The compound of embodiment 8, wherein Het is selected from pyrrolidine-2-one, oxazolidin-2-one, and imidazolidin-2-one, and is optionally substituted with Y. In particular embodiments of these compounds, Het is selected from: where the dashed bond indicates the point of attachment of Het to the remainder of Formula (I) or (IA), and (Y) 0-1 represents an optional substituent Y that can be attached at any available position on the ring. 10. The compound of embodiment 8, wherein Het is oxazolidin-2-one and is optionally substituted with -L 2< -N(R 10< ) 2 or L 2< -NR 10< -C(=NR 10< )-N(R 10< ) 2 11. The compound of embodiment 8, wherein Het is oxazolidin-2-one that is substituted on the 5-position with -L 2< -N(R 10< ) 2 or L 2< -NR 10< -C(=NR 10< )-N(R 10< ) 2 in the R-configuration 12. The compound of any of the preceding embodiments, having the structure of Formula (II): or a pharmaceutically acceptable salt thereof. 13. The compound of embodiment 1 or embodiment 2, wherein ---O-CR 1< R 2< R 3< is selected from and 14. The compound of embodiment 1 or embodiment 13, wherein Het is selected from 15. The compound of any of embodiments 1-10, wherein L 2< is -(CH 2 ) 1-3 -. 16. The compound of embodiment 12 wherein Het is selected from: 17. The compound of embodiment 18, wherein Het is selected from 18. The compound of embodiment 16 or 17, wherein Y is selected from Q, -L 2< -OR 10< , -L 2< -N(R 10< ) 2 , -L 2< -N(R 11< ) 3 , -L 2< -NR 10< -C(O)R 10< , -, -L 2< -O-C(O)OR 10< , -L 2< -O-C(O)-N(R 10< ) 2 , -L 2 -NR 10< -C(O)-N(R 10< ) 2 , -L 2< -C(=NR 10< )-N(R 10< ) 2 , -CON(R 10< ) 2< , -L 2< -NR 10 -C(=NR 10< )-N(R 10< ) 2 , and -L 2-< NR 10 -C(=NR 10< )-R 10< .

[0037] Alternatively, the compound of embodiment 16 or 17 wherein Y is of the formula -L 2< -NR 10< -L 2< -N(R 10< ) 2 , e.g. Y can be a group such as -CH 2 -NR 10< -(CH 2 ) 2-3 -N(R 10< ) 2 ; in particular embodiments of these compounds, R 10< is H. 19. The compound of any of embodiments 6-17, wherein R 3< is of the formula 20. The compound of embodiment 19, wherein R 3< is where R 3b< is selected from H, azetidine, pyrrolidine and piperidine. 21. The compound of any of the preceding embodiments, which is a pharmaceutically acceptable salt. 22. A pharmaceutical composition comprising a compound of any of the preceding embodiments and at least one pharmaceutically acceptable excipient. 23. A compound of any of embodiments 1-20, or a pharmaceutical composition of embodiment 22 for use in a method to treat a Gram-negative bacterial infection. 24. The compound or composition for use of embodiment 23, wherein the bacterial infection is caused by a species of Burkholderia, Citrobacter, Enterobacter, Escherichia, Klebsiella, Meningitidis, Morganella, Pseudomonas, Proteus, Salmonella, Serratia, Acinetobacter, Bacteroides, Campylobacter, Neisseria, or Stenotrophomonas bacteria. 25. The compound or composition for use of embodiment 23, wherein the bacterial infection is nosocomial pneumonia, an intraabdominal infection, or a urinary tract infection caused by a species of Enterobacteriaceae. 26. A compound according to any of embodiments 1-20 for use as a medicament. 27. The compound for use of embodiment 26, wherein the medicament is an antibacterial agent. 28. The compound for use of embodiment 26, wherein the antibacterial agent is for treatment of a Gram-negative bacterial infection caused by a species of Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Pseudomonas, Proteus, Salmonella, Serratia, Acinetobacter, Bacteroides, Burkholderia, Campylobacter, Neisseria, or Stenotrophomonas. 29. A pharmaceutical combination, comprising a compound according to any of embodiments 1-20 and a second therapeutic agent.

[0038] In compounds of Formula (I) and various embodiments described above, the oxime is preferably of the configuration shown here:

[0039] In some instances of any of the embodiments described above, unless otherwise specified, one but not both of R 2< and R 3< represent -COOH.

[0040] Where R 3< in any of the above embodiments is of the formula -L 1< -W-(CH 2 ) 0-2 -X-R 5< , X can be phenyl. In some of these embodiments, L 1< is CH 2 . In some such embodiments, W is O. In some of these embodiments, R 5< is a group of the formula wherein R 1b< , R 2b< and R 3b< are as described for embodiment 1 above. In certain of these embodiments, R 5< is of the formula wherein R 1b< and R 2b< each represent H, and R 3b< can be H, or a heterocyclic group such as 4-piperidinyl. Suitably, in these embodiments R 1< is H and R 2< is H or COOH.

[0041] In a further aspect, the invention provides: A pharmaceutical combination comprising (a) a first therapeutic agent which is a compound of the invention, e.g. a compound of formula (I) or any subformula thereof described herein, and (b) a second therapeutic agent as described above. A compound of formula (I) for use in a method as defined above comprising co-administration, e.g. concomitantly or in sequence, of a therapeutically effective amount of a compound of the invention, e.g. a compound of formula (I) or any subformulae thereof that is described herein, and a second therapeutic agent as described above.

[0042] The terms "co-administration" or "combined administration" or the like as utilized herein are meant to encompass administration of the selected therapeutic agents to a single patient, and are intended to include treatment regimens in which the agents are not necessarily administered by the same route of administration or at the same time. Fixed combinations are also within the scope of the present invention. The administration of a pharmaceutical combination of the invention results in a beneficial effect, e.g. a synergistic therapeutic effect, compared to a monotherapy applying only one of its pharmaceutically active ingredients.

[0043] Each component of a combination according to this invention may be administered separately, together, or in any combination thereof.

[0044] The compound of the invention and any additional agent may be formulated in separate dosage forms. Alternatively, to decrease the number of dosage forms administered to a patient, the compound of the invention and any additional agent may be formulated together in any combination. For example, the compound of the invention inhibitor may be formulated in one dosage form and the additional agent may be formulated together in another dosage form. Any separate dosage forms may be administered at the same time or different times.

[0045] Alternatively, a composition of this invention comprises an additional agent as described herein. Each component may be present in individual compositions, combination compositions, or in a single composition.

[0046] The compounds of the invention may be synthesized by the general synthetic routes below, specific examples of which are described in more detail in the Examples.

[0047] Compounds of the present invention and intermediates can also be converted into each other according to methods generally known to those skilled in the art.

[0048] Within the scope of this text, only a readily removable group that is not a constituent of the particular desired end product of the compounds of the present invention is designated a "protecting group", unless the context indicates otherwise. The protection of functional groups by such protecting groups, the protecting groups themselves, and their cleavage reactions are described for example in standard reference works, such as J. F. W. McOmie, "Protective Groups in Organic Chemistry", Plenum Press, London and New York 1973, in T. W. Greene and P. G. M. Wuts, "Protective Groups in Organic Synthesis", Third edition, Wiley, New York 1999, in "The Peptides"; Volume 3 (editors: E. Gross and J. Meienhofer), Academic Press, London and New York 1981, in "Methoden der organischen Chemie" (Methods of Organic Chemistry), Houben Weyl, 4th edition, Volume 15 / l, Georg Thieme Verlag, Stuttgart 1974, in H.-D. Jakubke and H. Jeschkeit, "Aminosauren, Peptide, Proteine" (Amino acids, Peptides, Proteins), Verlag Chemie, Weinheim, Deerfield Beach, and Basel 1982, and in Jochen Lehmann, "Chemie der Kohlenhydrate: Monosaccharide und Derivate" (Chemistry of Carbohydrates: Monosaccharides and Derivatives), Georg Thieme Verlag, Stuttgart 1974. A characteristic of protecting groups is that they can be removed readily (i.e. without the occurrence of undesired secondary reactions) for example by solvolysis, reduction, photolysis or alternatively under physiological conditions (e.g. by enzymatic cleavage).

[0049] Salts of compounds of the present invention having at least one salt-forming group may be prepared in a manner known to those skilled in the art. For example, salts of compounds of the present invention having acid groups may be formed, for example, by treating the compounds with metal compounds, such as alkali metal salts of suitable organic carboxylic acids, e.g. the sodium salt of 2-ethylhexanoic acid, with organic alkali metal or alkaline earth metal compounds, such as the corresponding hydroxides, carbonates or hydrogen carbonates, such as sodium or potassium hydroxide, carbonate or hydrogen carbonate, with corresponding calcium compounds or with ammonia or a suitable organic amine, stoichiometric amounts or only a small excess of the salt-forming agent preferably being used. Acid addition salts of compounds of the present invention are obtained in customary manner, e.g. by treating the compounds with an acid or a suitable anion exchange reagent. Internal salts of compounds of the present invention containing acid and basic salt-forming groups, e.g. a free carboxy group and a free amino group, may be formed, e.g. by the neutralisation of salts, such as acid addition salts, to the isoelectric point, e.g. with weak bases, or by treatment with ion exchangers.

[0050] Salts can be converted into the free compounds in accordance with methods known to those skilled in the art. Metal and ammonium salts can be converted, for example, by treatment with suitable acids, and acid addition salts, for example, by treatment with a suitable basic agent.

[0051] Mixtures of isomers obtainable according to the invention can generally be separated in a manner known to those skilled in the art into the individual isomers; diastereoisomers can be separated, for example, by partitioning between polyphasic solvent mixtures, recrystallization and / or chromatographic separation, for example over silica gel or by e.g. medium pressure liquid chromatography over a reversed phase column, and racemates can be separated, for example, by the formation of salts with optically pure salt-forming reagents and separation of the mixture of diastereoisomers so obtainable, for example by means of fractional crystallization, or by chromatography over optically active column materials.

[0052] Intermediates and final products can be worked up and / or purified according to standard methods, e.g. using chromatographic methods, distribution methods, (re-) crystallization, and the like.

[0053] The following applies in general to all processes mentioned herein before and hereinafter.

[0054] All process steps for making compounds of the invention can be carried out under reaction conditions that are known to those skilled in the art, including those mentioned specifically, in the absence or, customarily, in the presence of solvents or diluents, including, for example, solvents or diluents that are inert towards the reagents used and dissolve them, in the absence or presence of catalysts, condensation or neutralizing agents, for example ion exchangers, such as cation exchangers, e.g. in the H+ form, depending on the nature of the reaction and / or of the reactants at reduced, normal or elevated temperature, for example in a temperature range of from about -100 °C to about 190 °C, including, for example, from approximately -80 °C to approximately 150 °C, for example at from -80 to -60 °C, at room temperature, at from -20 to 40 °C or at reflux temperature, under atmospheric pressure or in a closed vessel, where appropriate under pressure, and / or in an inert atmosphere, for example under an argon or nitrogen atmosphere.

[0055] At all stages of the reactions, mixtures of isomers that are formed can be separated into the individual isomers, for example diastereoisomers or enantiomers, or into any desired mixtures of isomers, for example racemates or mixtures of diastereoisomers

[0056] The solvents from which those solvents that are suitable for any particular reaction may be selected include those mentioned specifically or, for example, water, esters, such as lower alkyl-lower alkanoates, for example ethyl acetate, ethers, such as aliphatic ethers, for example diethyl ether, or cyclic ethers, for example tetrahydrofuran or dioxane, liquid aromatic hydrocarbons, such as benzene or toluene, alcohols, such as methanol, ethanol or 1- or 2-propanol, nitriles, such as acetonitrile, halogenated hydrocarbons, such as methylene chloride or chloroform, acid amides, such as dimethylformamide or dimethyl acetamide, bases, such as heterocyclic nitrogen bases, for example pyridine or N-methylpyrrolidin-2-one, carboxylic acid anhydrides, such as lower alkanoic acid anhydrides, for example acetic anhydride, cyclic, linear or branched hydrocarbons, such as cyclohexane, hexane or isopentane, methycyclohexane, or mixtures of those solvents, for example aqueous solutions, unless otherwise indicated in the description of the processes. Such solvent mixtures may also be used in working up, for example by chromatography or partitioning.

[0057] The compounds of the present invention, including their salts, may also be obtained in the form of hydrates, or their crystals may, for example, include the solvent used for crystallization. Different crystalline forms may be present.

[0058] All starting materials, building blocks, reagents, acids, bases, dehydrating agents, solvents and catalysts utilized to synthesize the compounds of the present invention are either commercially available or can be produced by organic synthesis methods known to one of ordinary skill in the art.

[0059] The term "optical isomer" or "a stereoisomer" refers to any of the various stereoisomeric configurations which may exist for a given compound of the present invention and includes geometric isomers. It is understood that a substituent may be attached at a chiral center of a carbon atom. The term "chiral" refers to molecules which have the property of non-superimposability on their mirror image partner, while the term "achiral" refers to molecules which are superimposable on their mirror image partner. Therefore, the invention includes enantiomers, diastereomers or racemates of the compound. "Enantiomers" are a pair of stereoisomers that are non- superimposable mirror images of each other. A 1:1 mixture of a pair of enantiomers is a "racemic" mixture. The term is used to designate a racemic mixture where appropriate. "Diastereoisomers" are stereoisomers that have at least two asymmetric atoms, but which are not mirror-images of each other. The absolute stereochemistry is specified according to the Cahn- Ingold- Prelog R-S system. When a compound is a pure enantiomer the stereochemistry at each chiral carbon may be specified by either R or S. Resolved compounds whose absolute configuration is unknown can be designated (+) or (-) depending on the direction (dextro- or levorotatory) which they rotate plane polarized light at the wavelength of the sodium D line. Certain compounds described herein contain one or more asymmetric centers or axes and may thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-.

[0060] Depending on the choice of the starting materials and procedures, the compounds can be present in the form of one of the possible isomers or as mixtures thereof, for example as pure optical isomers, or as isomer mixtures, such as racemates and diastereoisomer mixtures, depending on the number of asymmetric carbon atoms. The present invention is meant to include all such possible stereoisomers, including racemic mixtures, diasteriomeric mixtures and optically pure forms. Optically active (R)- and (S)- isomers may be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques. If the compound contains a double bond, the substituent may be E or Z configuration. If the compound contains a disubstituted cycloalkyl, the cycloalkyl substituent may have a cis- or trans-configuration. All tautomeric forms are also intended to be included.

[0061] Any resulting mixtures of isomers can be separated on the basis of the physicochemical differences of the constituents, into the pure or substantially pure geometric or optical isomers, diastereomers, racemates, for example, by chromatography and / or fractional crystallization.

[0062] Any resulting racemates of final products or intermediates can be resolved into the optical antipodes by known methods, e.g., by separation of the diastereomeric salts thereof, obtained with an optically active acid or base, and liberating the optically active acidic or basic compound. In particular, a basic moiety may thus be employed to resolve the compounds of the present invention into their optical antipodes, e.g., by fractional crystallization of a salt formed with an optically active acid, e.g., tartaric acid, dibenzoyl tartaric acid, diacetyl tartaric acid, di-O,O'-p-toluoyl tartaric acid, mandelic acid, malic acid or camphor-10-sulfonic acid. Racemic products can also be resolved by chiral chromatography, e.g., high pressure liquid chromatography (HPLC) using a chiral adsorbent.

[0063] Furthermore, the compounds of the present invention, including their salts, can also be obtained in the form of their hydrates, or include other solvents used for their crystallization. The compounds of the present invention may inherently or by design form solvates with pharmaceutically acceptable solvents (including water); therefore, it is intended that the invention embrace both solvated and unsolvated forms. The term "solvate" refers to a molecular complex of a compound of the present invention (including pharmaceutically acceptable salts thereof) with one or more solvent molecules. Such solvent molecules are those commonly used in the pharmaceutical art, which are known to be innocuous to the recipient, e.g., water, ethanol, and the like. The term "hydrate" refers to the complex where the solvent molecule is water.

[0064] The compounds of the present invention, including salts, hydrates and solvates thereof, may inherently or by design form polymorphs.

[0065] As used herein, the terms "salt" or "salts" refers to an acid addition or base addition salt of a compound of the present invention. "Salts" include in particular "pharmaceutically acceptable salts". The term "pharmaceutically acceptable salts" refers to salts that retain the biological effectiveness and properties of the compounds of this invention and, which typically are not biologically or otherwise undesirable. In many cases, the compounds of the present invention are capable of forming acid and / or base salts by virtue of the presence of amino and / or carboxyl groups or groups similar thereto.

[0066] Pharmaceutically acceptable acid addition salts can be formed with inorganic acids and organic acids, e.g., acetate, aspartate, benzoate, besylate, bromide / hydrobromide, bicarbonate / carbonate, bisulfate / sulfate, camphorsulfonate, chloride / hydrochloride, chlortheophyllonate, citrate, ethandisulfonate, fumarate, gluceptate, gluconate, glucuronate, hippurate, hydroiodide / iodide, isethionate, lactate, lactobionate, laurylsulfate, malate, maleate, malonate, mandelate, mesylate, methylsulphate, naphthoate, napsylate, nicotinate, nitrate, octadecanoate, oleate, oxalate, palmitate, pamoate, phosphate / hydrogen phosphate / dihydrogen phosphate, polygalacturonate, propionate, stearate, succinate, sulfosalicylate, tartrate, tosylate and trifluoroacetate salts.

[0067] Inorganic acids from which salts can be derived include, for example, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like.

[0068] Organic acids from which salts can be derived include, for example, acetic acid, propionic acid, glycolic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, sulfosalicylic acid, and the like. Pharmaceutically acceptable base addition salts can be formed with inorganic and organic bases.

[0069] Inorganic bases from which salts can be derived include, for example, ammonium salts and metals from columns I to XII of the periodic table. In certain embodiments, the salts are derived from sodium, potassium, ammonium, calcium, magnesium, iron, silver, zinc, and copper; particularly suitable salts include ammonium, potassium, sodium, calcium and magnesium salts.

[0070] Organic bases from which salts can be derived include, for example, primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, basic ion exchange resins, and the like. Certain organic amines include isopropylamine, benzathine, cholinate, diethanolamine, diethylamine, lysine, meglumine, piperazine and tromethamine.

[0071] The pharmaceutically acceptable salts of the present invention can be synthesized from a basic or acidic moiety, by conventional chemical methods. Generally, such salts can be prepared by reacting free acid forms of these compounds with a stoichiometric amount of the appropriate base (such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate or the like), or by reacting free base forms of these compounds with a stoichiometric amount of the appropriate acid. Such reactions are typically carried out in water or in an organic solvent, or in a mixture of the two. Generally, use of non-aqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile is desirable, where practicable. Additional suitable salts can be found, e.g., in "Remington's Pharmaceutical Sciences", 20th ed., Mack Publishing Company, Easton, Pa., (1985); and in "Handbook of Pharmaceutical Salts: Properties, Selection, and Use" by Stahl and Wermuth (Wiley-VCH, Weinheim, Germany, 2002).

[0072] Any formula given herein is also intended to represent unlabeled forms as well as isotopically labeled forms of the compounds of the present invention. Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, and chlorine, such as 2< H, 3< H, 11< C, 13< C, 14< C, 15< N, 18< F 31< P, 32< P, 35< S, 36< Cl, 125< I respectively. The invention includes various isotopically labeled compounds of the present invention, for example those into which radioactive isotopes, such as 3< H and 14< C, or those into which non-radioactive isotopes, such as 2< H and 13< C are present. Such isotopically labelled compounds are useful in metabolic studies (with 14< C), reaction kinetic studies (with, for example 2< H or 3< H), detection or imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT) including drug or substrate tissue distribution assays, or in radioactive treatment of patients. In particular, an 18< F labeled compound of the present invention may be particularly desirable for PET or SPECT studies. Isotopically-labeled compounds of the present invention can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopically-labeled reagent in place of the non-labeled reagent previously employed.

[0073] Further, substitution with heavier isotopes, particularly deuterium (i.e., 2< H or D) may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements or an improvement in therapeutic index. It is understood that deuterium in this context is regarded as a substituent of a compound of the present invention. The concentration of such a heavier isotope, specifically deuterium, may be defined by the isotopic enrichment factor. The term "isotopic enrichment factor" as used herein means the ratio between the isotopic abundance and the natural abundance of a specified isotope. If a substituent in a compound of this invention is denoted deuterium, such compound has an isotopic enrichment factor for each designated deuterium atom of at least 3500 (52.5% deuterium incorporation at each designated deuterium atom), at least 4000 (60% deuterium incorporation), at least 4500 (67.5% deuterium incorporation), at least 5000 (75% deuterium incorporation), at least 5500 (82.5% deuterium incorporation), at least 6000 (90% deuterium incorporation), at least 6333.3 (95% deuterium incorporation), at least 6466.7 (97% deuterium incorporation), at least 6600 (99% deuterium incorporation), or at least 6633.3 (99.5% deuterium incorporation).

[0074] Pharmaceutically acceptable solvates in accordance with the invention include those wherein the solvent of crystallization may be isotopically substituted, e.g. D 2 O, d 6 -acetone, d 6 -DMSO.

[0075] Compounds of the present invention that contain groups capable of acting as donors and / or acceptors for hydrogen bonds may be capable of forming co-crystals with suitable co-crystal formers. These co-crystals may be prepared from compounds of the present invention by known co-crystal forming procedures. Such procedures include grinding, heating, co-subliming, co-melting, or contacting in solution compounds of the present invention with the co-crystal former under crystallization conditions and isolating co-crystals thereby formed. Suitable co-crystal formers include those described in WO 2004 / 078163. Hence the invention further provides co-crystals comprising a compound of the present invention.

[0076] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed.

[0077] The present invention provides novel compounds, pharmaceutical formulations including the compounds, and methods of treating Gram-negative bacterial infections. Particularly, the compounds are suitable for use to treat infections caused by Burkholderia, Citrobacter, Enterobacter, Escherichia, Klebsiella, Meningitidis, Morganella, Pseudomonas, Proteus, Salmonella, Serratia, Acinetobacter, Bacteroides, Campylobacter, Neisseria, or Stenotrophomonas bacteria, including species named herein.

[0078] Substitution with heavier isotopes such as deuterium, i.e. 2< H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances. For example, deuterium substitution at non-exchangeable hydrocarbon bonds (e.g., C-H) may retard epimerization and / or metabolic oxidation in vivo.

[0079] Isotopically-labeled compounds of the invention, i.e. compounds of formula (I), can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations Sections using an appropriate isotopically-labeled reagent in place of the non-labeled reagent previously.

[0080] In still another aspect, the invention provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, for use in a method of treating a subject with a Gram-negative bacterial infection, the method comprising the step of administering to the subject in need thereof an antibacterially effective amount of a compound of the invention, e.g., a compound of Formula (I), or salt thereof, with a pharmaceutically acceptable carrier.

[0081] The compounds of the invention also are useful in the treatment of patients suffering from or susceptible to pneumonia, sepsis, cystic fibrosis, wound, complicated diabetic foot or complicated urinary tract infections and sexually transmitted diseases caused by Gram-negative pathogens. The compounds of the invention also are useful in the conditions that are caused by a species of Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Proteus, Salmonella, Serratia, Pseudomonas, Acinetobacter, Bacteroides, Burkholderia, Campylobacter, Neisseria, or Stenotrophomonas. In particular, a bacterial infection caused by a species of Citrobacter, Enterobacter, Escherichia, Klebsiella, Morganella, Proteus, Salmonella, Serratia, Pseudomonas, or Acinetobacter is treatable by methods herein. Particular bacterial species for such treatment include Citrobacter freundii, Citrobacter koseri, Enterobacter cloacae, Enterobacter faecalis, Enterobacter faecium, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Morganella morganii, Proteus mirabilis, Salmonella species, Serratia marcescens, Pseudomonas aeruginosa, and Acinetobacter baumanii, as well as Bacteroides bivius, Bacteroides fragilis, Burkholderia cepacia, Campylobacter jejuni, Neisseria gonorrhoeae, and Stenotrophomonas maltophilia.

[0082] A compound of the present invention may also be used in combination with other agents, e.g., an additional antibiotic agent that is or is not of the formula (I), for treatment of a bacterial infection in a subject, or a compound that enhances the antibacterial activity of the compounds of the invention, including potentiators such as beta-lactamase inhibitors (BLIs). Suitable BLIs for use in combination with the compounds of the invention, including compounds of Formula (I) and subgenera thereof, include avibactam, clavulanic acid, sulbactam, tazobactam, and other compounds of the formula wherein M is H or a pharmaceutically acceptable cation, and R represents CN,-C(O)NR 1< R 2< , or an optionally substituted 5-6 membered heterocyclic or heteroaryl group. Suitable amides include those where R 1< is H or C 1-4 alkyl, and R 2< is optionally substituted C 1-4 alkyl, optionally substituted C 1-4 alkoxy, optionally substituted C 1-4 alkylamino, an optionally substituted C 5-6 heterocyclic group, or -NH-C(O)-R 3< , where R 3< is optionally substituted C 1-4 alkyl, optionally substituted C 1-4 alkoxy, optionally substituted C 1-4 alkylamino, an optionally substituted C 5-6 heterocyclic group. Each heterocyclic or heteroaryl group in these compounds contains 1-2 heteroatoms selected from N, O and S as ring members, and each optionally substituted group can be substituted by 1-2 groups selected from CN, halo, -OH, C 1-4 alkyl, C 1-4 alkoxy, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, -COO(C 1-4 alkyl), and 5-6 membered heterocyclic groups. Suitable compounds of this formula are described in WO2008 / 039420, WO2009 / 091856, WO2013 / 122888, WO2010 / 126820, WO2009 / 091856, WO2013 / 038330, US2013 / 0225554, WO2013149121, WO2013149136, WO2014141132 and WO2014 / 033560.

[0083] By the term "combination", is meant either a fixed combination in one dosage unit form, or a kit or instructions for the combined administration where a compound of the present invention and a combination partner may be administered independently at the same time or separately within time intervals that especially allow that the combination partners show a cooperative, e.g., synergistic, effect, or any combination thereof.

[0084] An embodiment of the present invention provides compounds of the present invention in a pharmaceutical combination with a second therapeutic agent. In some embodiments, the second therapeutic agent is an antibacterial agent. Non-limiting examples of antibacterial agents for use in pharmaceutical combinations of the invention may be selected from the following groups: (1) Macrolides or ketolides such as erythromycin, azithromycin, clarithromycin, and telithromycin; (2) Beta-lactams including penicillin such as penicillin G, penicillin V, methicillin, oxacillin, cloxacillin, dicloxacillin, nafcillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, mezlocillin, piperacillin, azlocillin, temocillin, cephalosporin such as cepalothin, cephapirin, cephradine, cephaloridine, cefazolin, cefamandole, cefuroxime, cephalexin, cefprozil, cefaclor, loracarbef, cefoxitin, cefinetazole, cefotaxime, ceftizoxime, ceftriaxone, cefoperazone, ceftazidime, cefixime, cefpodoxime, ceftibuten, cefdinir, cefpirome, cefepime, and carbapenems such as doripenem, imipenem, meropenem and PZ-601; (3) Glycopeptides such as vancomycin and teicoplanin; (4) Quinolones such asnalidixic acid, oxolinic acid, norfloxacin, pefloxacin, enoxacin, ofloxacin, levofloxacin, ciprofloxacin, temafloxacin, lomefloxacin, fleroxacin, grepafloxacin, sparfloxacin, trovafloxacin, clinafloxacin, gatifloxacin, moxifloxacin, sitafloxacin, ganefloxacin, gemifloxacin and pazufloxacin; (5) Antibacterial sulfonamides and antibacterial sulphanilamides, including para-aminobenzoic acid, sulfadiazine, sulfisoxazole, sulfamethoxazole and sulfathalidine; (6) Aminoglycosides such as streptomycin, neomycin, kanamycin, paromycin, gentamicin, tobramycin, amikacin, netilmicin, spectinomycin, sisomicin, dibekalin and isepamicin; (7) Tetracyclines such as tetracycline, chlortetracycline, demeclocycline, minocycline, oxytetracycline, methacycline, doxycycline, tigecycline; (8) Rifamycins such as rifampicin (also called rifampin), rifapentine, rifabutin, bezoxazinorifamycin and rifaximin; (9) Lincosamides such as lincomycin and clindamycin; (10) Streptogramins such as quinupristin and daflopristin; (11) Oxazolidinones such as linezolid or tedizolid; (12) Polymyxin, colistin and colymycin; (13) Trimethoprim and bacitracin; (14) Efflux pump inhibitors; (15) Beta-lactamase inhibitors, including avibactam and analogs thereof, and those described above.

[0085] The second antibacterial agent may be administered in combination with the compounds of the present invention wherein the second antibacterial agent is administered prior to, simultaneously, or after the compound or compounds of the present invention. When simultaneous administration of a compound of the invention with a second agent is desired and the route of administration is the same, then a compound of the invention may be formulated with a second agent into the same dosage form. An example of a dosage form containing a compound of the invention and a second agent is an intravenous administration. An alternative example is an intramuscular administration of a solution comprising a compound of the invention and a second agent.

[0086] The compounds and compositions described herein can be used or administered in combination with one or more therapeutic agents that act as immunomodulators, e.g., an activator of a costimulatory molecule, or an inhibitor of an immune-inhibitory molecule, or a vaccine. The Programmed Death 1 (PD-1) protein is an inhibitory member of the extended CD28 / CTLA4 family of T cell regulators (Okazaki et al. (2002) Curr Opin Immunol 14: 391779-82; Bennett et al. (2003) J. Immunol. 170:711-8). PD-1 is expressed on activated B cells, T cells, and monocytes. PD-1 is an immune-inhibitory protein that negatively regulates TCR signals (Ishida, Y. et al. (1992) EMBO J. 11:3887-3895; Blank, C. et al. (Epub 2006 Dec. 29) Immunol. Immunother. 56(5):739-745), and is up-regulated in chronic infections. The interaction between PD-1 and PD-L1 can act as an immune checkpoint, which can lead to, e.g., a decrease in infiltrating lymphocytes, a decrease in T-cell receptor mediated proliferation, and / or immune evasion by cancerous or infected cells (Dong et al. (2003) J. Mol. Med. 81:281-7; Blank et al. (2005) Cancer Immunol. Immunother. 54:307-314; Konishi et al. (2004) Clin. Cancer Res. 10:5094-100). Immune suppression can be reversed by inhibiting the local interaction of PD-1 with PD-L1 or PD-L2; the effect is additive when the interaction of PD-1 with PD-L2 is blocked as well (Iwai et al. (2002) Proc. Nat'l. Acad. Sci. USA 99:12293-7; Brown et al. (2003) J. Immunol. 170:1257-66). Immunomodulation can be achieved by binding to either the immune-inhibitory protein (e.g., PD-1) or to binding proteins that modulate the inhibitory protein (e.g., PD-L1, PD-L2).

[0087] In one embodiment, the combination therapies of the invention include an immunomodulator that is an inhibitor or antagonist of an inhibitory molecule of an immune checkpoint molecule. In another embodiment, the immunomodulator binds to a protein that naturally inhibits the immuno-inhibitory checkpoint molecule. When used in combination with antibacterial compounds, these immunomodulators can enhance the antimicrobial response, and thus enhance efficacy relative to treatment with the antibacterial compound alone.

[0088] The term "immune checkpoints" refers to a group of molecules on the cell surface of CD4 and CD8 T cells. These molecules can effectively serve as "brakes" to down-modulate or inhibit an adaptive immune response. Immune checkpoint molecules include, but are not limited to, Programmed Death 1 (PD-1), Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), B7H1, B7H4, OX-40, CD137, CD40, and LAG3, which directly inhibit immune cells. Immunotherapeutic agents which can act as immune checkpoint inhibitors useful in the methods of the present invention, include, but are not limited to, inhibitors of PD-L1, PD-L2, CTLA4, TIM3, LAG3, VISTA, BTLA, TIGIT, LAIR1, CD160, 2B4 and / or TGFR beta. Inhibition of an inhibitory molecule can be performed by inhibition at the DNA, RNA or protein level. In some embodiments, an inhibitory nucleic acid (e.g., a dsRNA, siRNA or shRNA), can be used to inhibit expression of an inhibitory molecule. In other embodiments, the inhibitor of an inhibitory signal is a polypeptide, e.g., a soluble ligand, or an antibody or antigen-binding fragment thereof, that binds to the inhibitory molecule.

[0089] By "in combination with," it is not intended to imply that the therapy or the therapeutic agents must be administered at the same time and / or formulated for delivery together, although these methods of delivery are within the scope described herein. The immunomodulator can be administered concurrently with, prior to, or subsequent to, one or more compounds of the invention, and optionally one or more additional therapies or therapeutic agents. The therapeutic agents in the combination can be administered in any order. In general, each agent will be administered at a dose and / or on a time schedule determined for that agent. It will further be appreciated that the therapeutic agents utilized in this combination may be administered together in a single composition or administered separately in different compositions. In general, it is expected that each of the therapeutic agents utilized in combination be utilized at levels that do not exceed the levels at which they are utilized individually. In some embodiments, the levels utilized in combination will be lower than those utilized individually.

[0090] In certain embodiments, the antibacterial compounds described herein are administered in combination with one or more immunomodulators that are inhibitors of PD-1, PD-L1 and / or PD-L2. Each such inhibitor may be an antibody, an antigen binding fragment thereof, an immunoadhesin, a fusion protein, or an oligopeptide. Examples of such immunomodulators are known in the art.

[0091] In some embodiments, the immunomodulator is an anti-PD-1 antibody chosen from MDX-1106, Merck 3475 or CT- 011.

[0092] In some embodiments, the immunomodulator is an immunoadhesin (e.g., an immunoadhesin comprising an extracellular or PD-1 binding portion of PD-LI or PD-L2 fused to a constant region (e.g., an Fc region of an immunoglobulin sequence).

[0093] In some embodiments, the immunomodulator is a PD-1 inhibitor such as AMP-224.

[0094] In some embodiments, the immunomodulator is a PD-LI inhibitor such as anti-PD-LI antibody.

[0095] In some embodiments, the immunomodulator is an anti-PD-LI binding antagonist chosen from YW243.55.S70, MPDL3280A, MEDI-4736, MSB-0010718C, or MDX-1105. MDX-1105, also known as BMS-936559, is an anti-PD-LI antibody described in WO2007 / 005874. Antibody YW243.55.S70 is an anti-PD-LI described in WO 2010 / 077634.

[0096] In some embodiments, the immunomodulator is nivolumab (CAS Registry Number: 946414-94-4). Alternative names for nivolumab include MDX-1106, MDX-1106-04, ONO-4538, or BMS-936558. Nivolumab is a fully human IgG4 monoclonal antibody which specifically blocks PD-1. Nivolumab (clone 5C4) and other human monoclonal antibodies that specifically bind to PD-1 are disclosed in US 8,008,449, EP2161336 and WO2006 / 121168.

[0097] In some embodiments, the immunomodulator is an anti-PD-1 antibody Pembrolizumab. Pembrolizumab (also referred to as Lambrolizumab, MK-3475, MK03475, SCH-900475 or KEYTRUDA®; Merck) is a humanized IgG4 monoclonal antibody that binds to PD-1. Pembrolizumab and other humanized anti-PD-1 antibodies are disclosed in Hamid, O. et al. (2013) New England Journal of Medicine 369 (2): 134-44, US 8,354,509, WO2009 / 114335, and WO2013 / 079174.

[0098] In some embodiments, the immunomodulator is Pidilizumab (CT-011; Cure Tech), a humanized IgG1k monoclonal antibody that binds to PD1. Pidilizumab and other humanized anti-PD-1 monoclonal antibodies are disclosed in WO2009 / 101611.

[0099] Other anti-PD1 antibodies useful as immunomodulators for use in the methods disclosed herein include AMP 514 (Amplimmune), and anti-PD1 antibodies disclosed in US 8,609,089, US 2010028330, and / or US 20120114649. In some embodiments, the anti-PD-L1 antibody is MSB0010718C. MSB0010718C (also referred to as A09-246-2; Merck Serono) is a monoclonal antibody that binds to PD-L1.

[0100] In some embodiments, the immunomodulator is MDPL3280A (Genentech / Roche), a human Fc optimized IgG1 monoclonal antibody that binds to PD-L1. MDPL3280A and other human monoclonal antibodies to PD-L1 are disclosed in U.S. Patent No.: 7,943,743 and U.S Publication No.: 20120039906. Other anti-PD-L1 binding agents useful as immunomodulators for methods of the invention include YW243.55.S70 (see WO2010 / 077634), MDX-1105 (also referred to as BMS-936559), and anti-PD-L1 binding agents disclosed in WO2007 / 005874.

[0101] In some embodiments, the immunomodulator is AMP-224 (B7-DCIg; Amplimmune; e.g., disclosed in WO2010 / 027827 and WO2011 / 066342), is a PD-L2 Fc fusion soluble receptor that blocks the interaction between PD1 and B7-H1.

[0102] In some embodiments, the immunomodulator is an anti-LAG-3 antibody such as BMS-986016. BMS-986016 (also referred to as BMS986016) is a monoclonal antibody that binds to LAG-3. BMS-986016 and other humanized anti-LAG-3 antibodies are disclosed in US 2011 / 0150892, WO2010 / 019570, and WO2014 / 008218.

[0103] In certain embodiments, the combination therapies disclosed herein include a modulator of a costimulatory molecule or an inhibitory molecule, e.g., a co-inhibitory ligand or receptor.

[0104] In one embodiment, the costimulatory modulator, e.g., agonist, of a costimulatory molecule is chosen from an agonist (e.g., an agonistic antibody or antigen-binding fragment thereof, or soluble fusion) of OX40, CD2, CD27, CDS, ICAM-1, LFA-1 (CD11a / CD18), ICOS (CD278), 4-1BB (CD137), GITR, CD30, CD40, BAFFR, HVEM, CD7, LIGHT, NKG2C, SLAMF7, NKp80, CD160, B7-H3 or CD83 ligand.

[0105] In another embodiment, the combination therapies disclosed herein include an immunomodulator that is a costimulatory molecule, e.g., an agonist associated with a positive signal that includes a costimulatory domain of CD28, CD27, ICOS and / or GITR.

[0106] Exemplary GITR agonists include, e.g., GITR fusion proteins and anti-GITR antibodies (e.g., bivalent anti-GITR antibodies), such as, a GITR fusion protein described in U.S. Patent No.: 6,111,090, European Patent No.: 090505B1, U.S Patent No.: 8,586,023, PCT Publication Nos.: WO 2010 / 003118 and 2011 / 090754, or an anti-GITR antibody described, e.g., in U.S. Patent No.: 7,025,962, European Patent No.: 1947183B1, U.S. Patent No.: 7,812,135, U.S. Patent No.: 8,388,967, U.S. Patent No.: 8,591,886, European Patent No.: EP 1866339, PCT Publication No.: WO 2011 / 028683, PCT Publication No. :WO 2013 / 039954, PCT Publication No.: WO2005 / 007190, PCT Publication No.: WO 2007 / 133822, PCT Publication No.: WO2005 / 055808, PCT Publication No.: WO 99 / 40196, PCT Publication No.: WO 2001 / 03720, PCT Publication No.: WO99 / 20758, PCT Publication No.: WO2006 / 083289, PCT Publication No.: WO 2005 / 115451, U.S. Patent No.: 7,618,632, and PCT Publication No.: WO 2011 / 051726.

[0107] In one embodiment, the immunomodulator used is a soluble ligand (e.g., a CTLA-4-Ig), or an antibody or antibody fragment that binds to PD-L1, PD-L2 or CTLA4. For example, the anti-PD-1 antibody molecule can be administered in combination with an anti-CTLA-4 antibody, e.g., ipilimumab, for example. Exemplary anti-CTLA4 antibodies include Tremelimumab (IgG2 monoclonal antibody available from Pfizer, formerly known as ticilimumab, CP-675,206); and Ipilimumab (CTLA-4 antibody, also known as MDX-010, CAS No. 477202-00-9).

[0108] In one embodiment, an anti-PD-1 antibody molecule is administered after treatment with a compound of the invention as described herein.

[0109] In another embodiment, an anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-LAG-3 antibody or an antigen-binding fragment thereof. In another embodiment, the anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-TIM-3 antibody or antigen-binding fragment thereof. In yet other embodiments, the anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-LAG-3 antibody and an anti-TIM-3 antibody, or antigen-binding fragments thereof. The combination of antibodies recited herein can be administered separately, e.g., as separate antibodies, or linked, e.g., as a bispecific or trispecific antibody molecule. In one embodiment, a bispecific antibody that includes an anti-PD-1 or PD-L1 antibody molecule and an anti-TIM-3 or anti-LAG-3 antibody, or antigen-binding fragment thereof, is administered. In certain embodiments, the combination of antibodies recited herein is used to treat a cancer, e.g., a cancer as described herein (e.g., a solid tumor). The efficacy of the aforesaid combinations can be tested in animal models known in the art. For example, the animal models to test the synergistic effect of anti-PD-1 and anti-LAG-3 are described, e.g., in Woo et al. (2012) Cancer Res. 72(4):917-27).

[0110] Exemplary immunomodulators that can be used in the combination therapies include, but are not limited to, e.g., afutuzumab (available from Roche®); pegfilgrastim (Neulasta®); lenalidomide (CC-5013, Revlimid®); thalidomide (Thalomid®), actimid (CC4047); and cytokines, e.g., IL-21 or IRX-2 (mixture of human cytokines including interleukin 1, interleukin 2, and interferon γ, CAS 951209-71-5, available from IRX Therapeutics).

[0111] Exemplary doses of such immunomodulators that can be used in combination with the antibacterial compounds of the invention include a dose of anti-PD-1 antibody molecule of about 1 to 10 mg / kg, e.g., 3 mg / kg, and a dose of an anti-CTLA-4 antibody, e.g., ipilimumab, of about 3 mg / kg.

[0112] Examples of embodiments of antibacterial compounds of the invention for use in combination with an immunomodulator in methods include embodiments wherein these methods are: i. A method to treat a bacterial infection in a subject, comprising administering to the subject a compound of Formula (I) as described herein, and an immunomodulator. ii. The method of embodiment i, wherein the immunomodulator is an activator of a costimulatory molecule or an inhibitor of an immune checkpoint molecule. iii. The method of either of embodiments i and ii, wherein the activator of the costimulatory molecule is an agonist of one or more of OX40, CD2, CD27, CDS, ICAM-1, LFA-1 (CD11a / CD18), ICOS (CD278), 4-1BB (CD137), GITR, CD30, CD40, BAFFR, HVEM, CD7, LIGHT, NKG2C, SLAMF7, NKp80, CD160, B7-H3 and CD83 ligand. iv. The method of any of embodiments i-iii above, wherein the inhibitor of the immune checkpoint molecule is chosen from PD-1, PD-L1, PD-L2, CTLA4, TIM3, LAG3, VISTA, BTLA, TIGIT, LAIR1, CD160, 2B4 and TGFR beta. v. The method of any of embodiments i-iii, wherein the inhibitor of the immune checkpoint molecule is chosen from an inhibitor of PD-1, PD-L1, LAG-3, TIM-3 or CTLA4, or any combination thereof. vi. The method of any of embodiments i-v, wherein the inhibitor of the immune checkpoint molecule is a soluble ligand or an antibody or antigen-binding fragment thereof, that binds to the immune checkpoint molecule. vii. The method of any of embodiments i-vi, wherein the antibody or antigen-binding fragment thereof is from an IgG1 or IgG4 (e.g., human IgG1 or IgG4). viii. The method of any of embodiments i-vii, wherein the antibody or antigen-binding fragment thereof is altered, e.g., mutated, to increase or decrease one or more of: Fc receptor binding, antibody glycosylation, the number of cysteine residues, effector cell function, or complement function. ix. The method of any of embodiments i-viii, wherein the antibody molecule is a bispecific or multispecific antibody molecule that has a first binding specificity to PD-1 or PD-L1 and a second binding specifity to TIM-3, LAG-3, or PD-L2. x. The method of any of embodiments i-ix, wherein the immunomodulator is an anti-PD-1 antibody chosen from Nivolumab, Pembrolizumab or Pidilizumab. xi. The method of any of embodiments i-x, wherein the immunomodulator is an anti-PD-L1 antibody chosen from YW243.55.S70, MPDL3280A, MEDI-4736, MSB-0010718C, or MDX-1105. xii. The method of any of embodiments i-x, wherein the immunomodulator is an anti-LAG-3 antibody molecule. xiii. The method of embodiment xii, wherein the anti-LAG-3 antibody molecule is BMS-986016, xiv. The method of any of embodiments i-x, wherein the immunomodulator is an anti-PD-1 antibody molecule administered by injection (e.g., subcutaneously or intravenously) at a dose of about 1 to 30 mg / kg, e.g., about 5 to 25 mg / kg, about 10 to 20 mg / kg, about 1 to 5 mg / kg, or about 3 mg / kg., e.g., once a week to once every 2, 3, or 4 weeks. xv. The method of embodiment xiv, wherein the anti-PD-1 antibody molecule is administered at a dose from about 10 to 20 mg / kg every other week. xvi. The method of embodiment xv, wherein the anti-PD-1 antibody molecule, e.g., nivolumab, is administered intravenously at a dose from about 1 mg / kg to 3 mg / kg, e.g., about 1 mg / kg, 2 mg / kg or 3 mg / kg, every two weeks. xvii. The method of embodiment xv, wherein the anti-PD-1 antibody molecule, e.g., nivolumab, is administered intravenously at a dose of about 2 mg / kg at 3-week intervals.

[0113] The language "effective amount" of the compound is that amount necessary or sufficient to treat or prevent a bacterial infection and / or a disease or condition described herein. In an example, an effective amount of the compound is an amount sufficient to treat bacterial infection in a subject. In another example, an effective amount of the compound is an amount sufficient to treat a bacterial infection, such as, but not limited to Pseudomonas aeruginosa and the like in a subject. The effective amount can vary depending on such factors as the size and weight of the subject, the type of illness, or the particular compound of the invention. For example, the choice of the compound of the invention can affect what constitutes an "effective amount." One of ordinary skill in the art would be able to study the factors contained herein and make the determination regarding the effective amount of the compounds of the invention without undue experimentation.

[0114] The regimen of administration can affect what constitutes an effective amount. The compound of the invention can be administered to the subject either prior to or after the onset of a bacterial infection. Typically, the compound is administered to a subject diagnosed as having a bacterial infection and in need of treatment therefor. Further, several divided dosages, as well as staggered dosages, can be administered daily or sequentially, or the dose can be continuously infused, or can be a bolus injection. Further, the dosages of the compound(s) of the invention can be proportionally increased or decreased as indicated by the exigencies of the therapeutic or prophylactic situation. Typically, the compound of the invention would be administered over a course of at least 5 days, more commonly at least 7 days or at least 10 days or at least 14 days.

[0115] Compounds of the invention may be used in the treatment of states, disorders or diseases as described herein, or for the manufacture of pharmaceutical compositions for use in the treatment of these diseases. The invention provides compounds of the present invention for use in the treatment of these diseases or pharmaceutical preparations having compounds of the present invention for use in the treatment of these diseases.

[0116] The language "pharmaceutical composition" includes preparations suitable for administration to mammals, e.g., humans. When the compounds of the present invention are administered as pharmaceuticals to mammals, e.g., humans, they can be given per se or as a pharmaceutical composition containing, for example, 0.1 to 99.5% (more preferably, 0.5 to 90%) of active ingredient in combination with a pharmaceutically acceptable carrier.

[0117] The phrase "pharmaceutically acceptable carrier" is art recognized and includes a pharmaceutically acceptable material, composition or vehicle, suitable for administering compounds of the present invention to mammals. The carriers include liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting the subject agent from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as pharmaceutically acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; phosphate buffer solutions; and other non-toxic compatible substances employed in pharmaceutical formulations. In some embodiments, a pharmaceutically acceptable carrier is sterilized before combination with the compound of the invention.

[0118] In some embodiments, the pharmaceutical composition of the invention comprises a compound of any of the numbered embodiments and at least one pharmaceutically acceptable carrier or excipient. In certain embodiments, the pharmaceutical composition of the invention comprises a compound of any of the numbered embodiments and at least two pharmaceutically acceptable carriers or excipients.

[0119] Wetting agents, emulsifiers and lubricants, such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, release agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the compositions.

[0120] Examples of pharmaceutically acceptable antioxidants include: water soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propyl gallate, α-tocopherol, and the like; and metal chelating agents, such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol, tartaric acid, phosphoric acid, and the like.

[0121] Formulations of the present invention include those suitable for oral, nasal, inhalation, topical, transdermal, buccal, sublingual, rectal, vaginal and / or parenteral administration. Typically, compounds of the invention would be administered intravenously, in the form of a solution that is often isotonic, such as a saline or glucose solution. The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. The amount of active ingredient that can be combined with a carrier material to produce a single dosage form will generally be that amount of the compound that produces a therapeutic effect. Generally, out of one hundred per cent, this amount will range from about 1 per cent to about ninety-nine percent of active ingredient, preferably from about 5 per cent to about 70 per cent, most preferably from about 10 per cent to about 30 per cent.

[0122] Methods of preparing these formulations or compositions include the step of bringing into association a compound of the present invention with the carrier and, optionally, one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association a compound of the present invention with liquid carriers, or finely divided solid carriers, or both, and then, if necessary, shaping the product.

[0123] Formulations of the invention suitable for oral administration may be in the form of capsules, cachets, pills, tablets, lozenges (using a flavored basis, usually sucrose and acacia or tragacanth), powders, granules, or as a solution or a suspension in an aqueous or non-aqueous liquid, or as an oil-in-water or water-in-oil liquid emulsion, or as an elixir or syrup, or as pastilles (using an inert base, such as gelatin and glycerin, or sucrose and acacia) and / or as mouth washes and the like, each containing a predetermined amount of a compound of the present invention as an active ingredient. A compound of the present invention may also be administered as a bolus, electuary or paste.

[0124] In solid dosage forms of the invention for oral administration (capsules, tablets, pills, dragees, powders, granules and the like), the active ingredient is mixed with one or more pharmaceutically acceptable carriers, such as sodium citrate or dicalcium phosphate, and / or any of the following: fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and / or silicic acid; binders, such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and / or acacia; humectants, such as glycerol; disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate; solution retarding agents, such as paraffin; absorption accelerators, such as quaternary ammonium compounds; wetting agents, such as, for example, cetyl alcohol and glycerol monostearate; absorbents, such as kaolin and bentonite clay; lubricants, such a talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof; and coloring agents. In the case of capsules, tablets and pills, the pharmaceutical compositions may also comprise buffering agents. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugars, as well as high molecular weight polyethylene glycols and the like.

[0125] A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared using binder (for example, gelatin or hydroxypropylmethyl cellulose), lubricant, inert diluent, preservative, disintegrant (for example, sodium starch glycolate or cross-linked sodium carboxymethyl cellulose), surface-active or dispersing agent. Molded tablets may be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent.

[0126] The tablets, and other solid dosage forms of the pharmaceutical compositions of the present invention, such as dragees, capsules, pills and granules, may optionally be scored or prepared with coatings and shells, such as enteric coatings and other coatings well known in the pharmaceutical-formulating art. They may also be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile, other polymer matrices, liposomes and / or microspheres. They may be sterilized by, for example, filtration through a bacteria-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions that can be dissolved in sterile water, or some other sterile injectable medium immediately before use. These compositions may also optionally contain opacifying agents and may be of a composition that they release the active ingredient(s) only, or preferentially, in a certain portion of the gastrointestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes. The active ingredient can also be in micro-encapsulated form, if appropriate, with one or more of the above-described excipients.

[0127] Liquid dosage forms for oral administration of the compounds of the invention include pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active ingredient, the liquid dosage forms may contain inert diluent commonly used in the art, such as, for example, water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.

[0128] Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, coloring, perfuming and preservative agents.

[0129] Suspensions, in addition to the active compounds, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

[0130] Formulations of the pharmaceutical compositions of the invention for rectal or vaginal administration may be presented as a suppository, which may be prepared by mixing one or more compounds of the invention with one or more suitable nonirritating excipients or carriers comprising, for example, cocoa butter, polyethylene glycol, a suppository wax or a salicylate, and which is solid at room temperature, but liquid at body temperature and, therefore, will melt in the rectum or vaginal cavity and release the active compound.

[0131] Formulations of the present invention which are suitable for vaginal administration also include pessaries, tampons, creams, gels, pastes, foams or spray formulations containing such carriers as are known in the art to be appropriate.

[0132] Dosage forms for the topical or transdermal administration of a compound of this invention include powders, sprays, ointments, pastes, creams, lotions, gels, solutions, patches and inhalants. The active compound may be mixed under sterile conditions with a pharmaceutically acceptable carrier, and with any preservatives, buffers, or propellants that may be required.

[0133] The ointments, pastes, creams and gels may contain, in addition to an active compound of this invention, excipients, such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc and zinc oxide, or mixtures thereof.

[0134] Powders and sprays can contain, in addition to a compound of this invention, excipients such as lactose, talc, silicic acid, aluminum hydroxide, calcium silicates and polyamide powder, or mixtures of these substances. Sprays can additionally contain customary propellants, such as chlorofluorohydrocarbons and volatile unsubstituted hydrocarbons, such as butane and propane.

[0135] Transdermal patches have the added advantage of providing controlled delivery of a compound of the present invention to the body. Such dosage forms can be made by dissolving or dispersing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate of such flux can be controlled by either providing a rate controlling membrane or dispersing the active compound in a polymer matrix or gel.

[0136] Ophthalmic formulations, eye ointments, powders, solutions and the like, are also contemplated as being within the scope of this invention.

[0137] Pharmaceutical compositions of this invention suitable for parenteral administration comprise one or more compounds of the invention in combination with one or more pharmaceutically acceptable sterile isotonic aqueous or nonaqueous solutions, dispersions, suspensions or emulsions, or sterile powders which may be reconstituted into sterile injectable solutions or dispersions just prior to use, which may contain antioxidants, buffers, bacteriostats, solutes which render the formulation isotonic with the blood of the intended recipient or suspending or thickening agents.

[0138] Examples of suitable aqueous and nonaqueous carriers that may be employed in the pharmaceutical compositions of the invention include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

[0139] These compositions may also contain adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms may be ensured by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the compositions. In addition, prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents that delay absorption such as aluminum monostearate and gelatin.

[0140] In some cases, in order to prolong the effect of a drug, it is desirable to slow the absorption of the drug from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material having poor water solubility. The rate of absorption of the drug then depends upon its rate of dissolution which, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally-administered drug form is accomplished by dissolving or suspending the drug in an oil vehicle.

[0141] Injectable depot forms are made by forming microencapsule matrices of the subject compounds in biodegradable polymers such as polylactide-polyglycolide. Depending on the ratio of drug to polymer, and the nature of the particular polymer employed, the rate of drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions that are compatible with body tissue.

[0142] The preparations of the present invention may be given orally, parenterally, topically, or rectally. They are of course given by forms suitable for each administration route. For example, they are administered in tablets or capsule form, by injection, inhalation, eye lotion, ointment, suppository, etc., administration by injection, infusion or inhalation; topical by lotion or ointment; and rectal by suppositories. Intravenous administration is preferred.

[0143] The phrases "parenteral administration" and "administered parenterally" as used herein means modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal and intrasternal injection and infusion.

[0144] The phrases "systemic administration," "administered systemically," "peripheral administration" and "administered peripherally" as used herein mean the administration of a compound, drug or other material other than directly into the central nervous system, such that it enters the patient's system and, thus, is subject to metabolism and other like processes, for example, subcutaneous administration.

[0145] These compounds may be administered to humans and other animals for therapy by any suitable route of administration, including orally, nasally, as by, for example, a spray, rectally, intravaginally, parenterally, intracisternally and topically, as by powders, ointments or drops, including buccally and sublingually.

[0146] Regardless of the route of administration selected, the compounds of the present invention, which may be used in a suitable hydrated form, and / or the pharmaceutical compositions of the present invention, are formulated into pharmaceutically acceptable dosage forms by conventional methods known to those of skill in the art.

[0147] Actual dosage levels of the active ingredients in the pharmaceutical compositions of this invention may be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular patient, composition, and mode of administration, without being toxic to the patient.

[0148] The selected dosage level will depend upon a variety of factors including the activity of the particular compound of the present invention employed, or the ester, salt or amide thereof, the route of administration, the time of administration, the rate of excretion of the particular compound being employed, the duration of the treatment, other drugs, compounds and / or materials used in combination with the particular compound employed, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.

[0149] In general, a suitable daily dose of a compound of the invention will be that amount of the compound that is the dose effective to produce a therapeutic effect. Such an effective dose will generally depend upon the factors described above. Generally, intravenous and subcutaneous doses of the compounds of this invention for a patient, when used for the indicated antibacterial effects, will range from about 5 to about 150 mg per kilogram of body weight per day, more preferably from about 15 to about 115 mg per kg per day, and still more preferably from about 20 to about 85 mg per kg per day. An effective amount is that amount treats a bacterial infection.

[0150] If desired, the effective daily dose of the active compound may be administered as two, three, four, five, six or more sub-doses administered separately at appropriate intervals throughout the day, optionally, in unit dosage forms, or as continuous infusion.

[0151] While it is possible for a compound of the present invention to be administered alone, it is preferable to administer the compound as a pharmaceutical composition.

[0152] The compounds as defined in embodiments may be synthesized by the general synthetic routes below, specific examples of which are described in more detail in the Examples.General Synthetic Schemes

[0153] One method for synthesizing compounds with formula (I) is described in Scheme A. An alcohol A-1 can be converted into A-2 following the "Mitsunobu" protocol, provided the heterocycle is sufficiently acidic to engage in a Misunobu reaction. Sulfonylation of A-2 provides A-3, which can be deprotected with TFA or formic acid to yield A-4.

[0154] Heterocyclic intermediates A-2 could also be obtained as outlined in Scheme C, by alkylation of an amine such as C-1. Suitable alkylation reagents include alkyl halides or epoxides. Alkylation of C-1 could also be effected by reductive amination with an appropriately functionalized and protected aldehyde. Cyclization of C-2 could be effected using a carbonylating agent like CDI. Examples of the group Y in these compounds include oxygen or NR 5< , e.g., NH.

[0155] The functionalized amines C-2 were alternatively obtained from B-1 by alkylation with a functionalized amine. A lactam heterocycle may analogously be obtained by alkylation of C-1 with brominated carboxylic esters, followed by base catalyzed cyclization. A heterocycle may be introduced to yield Intermediate A-2, by substitution of a leaving group in an appropriately protected azetidinone intermediate. Suitable protection groups include Cbz for the amine and DMB for the azetidinone. Deprotection of the Cbz group followed by acylation with appropriately functionalized and protected acids D-6 gave A-2, as outlined in Scheme D. Protected intermediates such as D-1 were also used for introduction of the heterocycle under Mitsunobu conditions, as outlined in Scheme A. D-1 was also converted to the corresponding azide, which was used for "click chemistry" to introduce 1-linked 1,2,3 triazoles following a similar sequence as outlined in Scheme B. D-1 can also be used to yield functionalized amine derivatives that can be converted to heterocycles, as described in Scheme C.

[0156] Intermediates of the type A-3 may also be assembled by the sequence outlined in Scheme E, whereby the oxime moiety is introduced after the coupling step. Compounds of the Formula (I) are prepared from commonly available compounds using these general schemes and procedures known to those skilled in the art along with the methods and examples provided herein.EXAMPLES

[0157] The invention is further illustrated by the following examples, which should not be construed as further limiting. The assays used throughout the Examples are accepted. Demonstration of efficacy in these assays is predictive of efficacy in subjects.General Conditions

[0158] Mass spectra were acquired on LC-MS, SFC-MS, or GC-MS systems using electrospray, chemical and electron impact ionization methods from a range of instruments of the following configurations: Waters ACQUITY UPLC system and equipped with a ZQ 2000 or SQD MS system where (M+1) refers to the protonated molecular ion of the chemical species, (M+) refers to the unprotonated quaternary ammonium cation, (M+Na) refers to the sodium-incorporated ion and (M-1) refers to the deprotonated molecular ion of the chemical species.

[0159] NMR spectra were run on Bruker AVANCE 500MHz or Varian 400MHz NMR spectrometers using ICON-NMR, under TopSpin program control. Spectra were measured at 298K, unless indicated otherwise, and were referenced relative to the solvent resonance.Instrumentation

[0160] MS Methods: Using Agilent 1100 HPLC systems with an Agilent 6110 Mass Spectrometer Method 2m_acidic:  Column  Kinetex C18 50 x 2.1 mm, 2.6 µm  Column Temperature  50 °C  Eluents  A: H 2 O, B: acetonitrile, both containing 0.1% TFA  Flow Rate  1.2 mL / minGradient2% to 88% B in 1.30 min, 0.15 min 95% B Method 2m_acidic_polar: ColumnKinetex C18 50 x 2.1 mm, 2.6 µmColumn Temperature50 °CEluentsA: H 2 O, B: acetonitrile, both containing 0.1% TFAFlow Rate1.2 mL / minGradient1% to 30% B in 1.30 min, 0.15 min 98% B Abbreviations:

[0161] ACNacetonitrile aqaqueous appapparent ATPadenosine 5'-triphosphate BINAPracemic 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl Boctertiary butyl carboxy brbroad brsbroad singlet BSAbovine serum albumin CDI1,1'-carbonyldiimidazole ddoublet dddoublet of doublets DCMdichloromethane DCE1,2-dichloroethane DIADdiisopropylazodicarboxylate DIPEAdiisopropylethylamine DME1,4-dimethoxyethane DMFN,N-dimethylformamide DMSOdimethylsulfoxide EDTAethylenediamine tetraacetic acid ESIelectrospray ionization EtOAcethyl acetate ggram hhour(s) HATU1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b] pyridinium 3-oxid hexafluorophosphate HBTU1-[bis(dimethylamino)methylene]-1H-benzotriazoliumhexafluorophosphate(1-)3-oxide HCIhydrochloric acid HOBt1-hydroxybenzotriazole HPLChigh performance liquid chromatography LCMSliquid chromatography and mass spectrometry mmultiplet m-CPBA3-chloroperbenzoic acid MeOHmethanol MSmass spectrometry mgmilligram minminutes mLmilliliter mmolmillimol m / zmass to charge ratio NMRnuclear magnetic resonance ppentet PdCl 2 (dppf)-CH 2 Cl 2 1,1'-Bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex PPh 3 triphenylphosphine ppmparts per million PyBOPbenzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate qquartet racracemic rtroom temperature R t retention time ssinglet satdsaturated ttriplet TBAFtetrabutylammonium fluoride TBMEmethyl tert-butyl ether TFAtrifluoroacetic acid THFtetrahydrofuran Tris·HClaminotris(hydroxymethyl)methane hydrochloride Preparation of Intermediates Intermediate A: ((2S,3S)-3-(((benzyloxy)carbonyl)amino)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-2-yl)methyl methanesulfonate.

[0162]

[0163] To a solution of benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate (5.37 g, 13.41 mmol) and TEA (3.72 mL, 26.8 mmol) in DCM at 0 °C was added MsCI (1.15 mL, 14.75 mmol). After stirring at 0 °C for 1 h, it was diluted with water / DCM and the layers were separated. The aqueous layer was extracted with DCM (2x) and the combined organic layers were washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was taken up in toluene and concentrated (2x), affording the title compound as an off white solid. It was used as such in subsequent reactions. LCMS: R t = 0.86 min, m / z = 479.2 (M+1) Method 2m_acidic.Intermediate B: tert-Butyl ((2H-tetrazol-5-yl)methyl)carbamate.

[0164]

[0165] To a flask charged with (2H-tetrazol-5-yl)methylamine (1.67 g, 16.85 mmol), Boc anhydride (3.86, 17.70 mmol) and water (16.85 mL) was added NaOH (4 N, 4.42 mL, 17.70 mmol). The resulting suspension was stirred at rt for 12 h then cooled to 0 °C, whereupon HCI (1N) was added until pH = 4-5. The precipitate was collected by filtration and the mother liquor was cooled to 0 °C and reacidified with HCI (1N) until pH = 4-5. More of the precipitate was collected and combined with the first batch, washing the lot with heptane to afford the title compound (2.74 g, 82%) as a white solid. LCMS: R t = 0.38 min, m / z = 200.2 (M+1) Method 2m_acidic.Intermediate C: tert-Butyl ((1H-1,2,4-triazol-3-yl)methyl)carbamate.

[0166]

[0167] To a solution of 2H-[1,2,4]triazole-3-yl-methylamine hydrochloride (583 mg, 4.33 mmol) and Boc-anhydride (993 mg, 4.55 mmol) in water (5.78 mL) was added NaOH (4N, 1.137 mL, 4.55 mmol). After stirring for 48 h the white precipitate was collected by filtration. The solid was suspended in heptane, sonicated then filtered, washing the filter cake with heptane. LCMS: R t = 0.41 min, m / z = 199.2 (M+1) Method 2m_acidic.Intermediate D: 3-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)oxazolidin-2-one.

[0168]

[0169] Step 1: Benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-(((2-hydroxyethyl)amino)methyl)-4-oxoazetidin-3-yl)carbamate. To a solution of ((2S,3S)-3-(((benzyloxy)carbonyl)amino)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-2-yl)methyl methanesulfonate (6.43g, 13.4 mmol) in Acetonitrile (44.8 ml) was added ethanolamine (8.13 ml, 134 mmol) followed by DIPEA (7.0 ml, 40 mmol). The solution was heated to 80°C for 20 h, whereupon it was cooled to rt, diluted with EtOAc, washed with water, dried over Na 2 SO 4 and concentrated in vacuo, afford the title compound (4.47 g, 75%) as a white solid. LCMS: R t = 0.60 min, m / z = 444.2 (M+1).

[0170] Step 2: Benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)carbamate. To a solution of benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-(((2-hydroxyethyl)amino)methyl)-4-oxoazetidin-3-yl)carbamate (4.47g, 10.08 mmol) in chloroform (50 ml) was added CDI (4.90 g, 30.2 mmol). After stirring at rt for 30 min it was concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-5%), affording the title compound (3.84 g, 81%) as a white foam. LCMS: R t = 0.76 min, m / z = 470.1 (M+1).

[0171] Step 3: Benzyl ((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)carbamate . Prepared in an analogous manner to example 4, step 2 using benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)carbamate (3.84 g, 8.18 mmol), K 2 S 2 O 8 (3.10 g, 11.5 mmol) and K 2 HPO 4 (1.852 g, 10.6 mmol) in ACN:water (2:1, 136 mL) while heating for 40 min at 90 °C. More K 2 S 2 O 8 (663 g, 2.45 mmol) and K 2 HPO 4 (370 mg, 2.13 mmol) were added and it was heated for another 3 h. More K 2 S 2 O 8 (332 mg, 1.23 mmol) and K 2 HPO 4 (185 mg, 1.06 mmol) were added, and it was heated for an additional 2 h, whereupon it was concentrated in vacuo, removing most of the ACN. The mixture was diluted with brine / EtOAc and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 . The crude residue was purified via silica gel chromatography (EtOAc-Heptane, 0-100% then MeOH-DCM, 10%) to afford the title compound (1.61 g, 62%) as a beige foam. LCMS: R t = 0.51 min, m / z = 320.0 (M+1) Method 2m_acidic.

[0172] Step 4: 3-((((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)oxazolidin-2-one. Prepared in an analogous manner to example 4, step 3 using benzyl ((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)carbamate (96 mg, 0.30 mmol) and Pd / C 10% Degussa type 101 (10%, 64 mg) in EtOH:MeOH (4:1, 1.5 mL) for 1 h. The crude residue was used as such in following step. LCMS: R t = 0.11 min, m / z = 186.0 (M+1) Method 2m_acidic.Intermediate E: tert-Butyl (4-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoacetyl)thiazol-2-yl)carbamate.

[0173]

[0174] To a slurry of 2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoacetic acid (2.72 g, 9.99 mmol) and HATU (3.80, 10.0 mmol) in DCM:DMF (3:1, 33.3 mL) at 0 °C was added DIPEA (2.91 mL, 16.7 mmol). A soln of (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (1.39 g, 8.33 mmol) in DCM:DMF (1:1, 32 mL) was added followed by a DMF (3 mL) wash. After stirring for 48 h the dark solution was diluted with EtOAc (150 mL) / brine (140 mL) and the layers were separated. The aqueous was extracted with EtOAc (3x) and the combined organic layers were washed with brine (70 mL). The brine layer wash was re-extracted with EtOAc. The combined organic layers were dried over Na 2 SO 4 and concd in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-10%), affording the title compound (2.38 g, 68%) as a red solid. LCMS: R t = 0.59 min, m / z = 422.0 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 11.85 (s, 1H), 9.70 (d, J = 9.3 Hz, 1H), 8.52 (d, J = 1.6 Hz, 1H), 8.48 (s, 1H), 8.44 (s, 1H), 7.96 (s, 1H), 5.28 (ddd, J = 9.3, 5.2, 1.5 Hz, 1H), 4.45 (dd, J = 14.2, 5.3 Hz, 1H), 4.36 (dd, J = 14.1, 7.6 Hz, 1H), 4.18 (dt, J = 7.6, 5.3 Hz, 1H), 1.47 (s, 9H).Intermediate F: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-(2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoacetamido)-4-oxoazetidine-1-sulfonic acid.

[0175]

[0176] To a soln of tert-Butyl (4-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoacetyl)thiazol-2-yl)carbamate (200 mg, 0.475 mmol) in DMF (4.75 mL) at 0 °C was added SO 3 •DMF (367 mg, 2.40 mmol). After 16 h of stirring it was concentrated in vacuo and purified with HP21 resin (ACN-water, 0-50%), affording the title compound (110 mg, 46%) as a pale yellow solid. LCMS: R t = 0.54 min, m / z = 501.9 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 11.87 (s, 1H), 9.75 (d, J = 9.2 Hz, 1H), 8.94 (s, 1H), 8.44 (s, 1H), 8.34 (s, 1H), 5.25 (dd, J = 9.1, 5.4 Hz, 1H), 4.75 (dd, J = 14.3, 4.9 Hz, 1H), 4.61 (dd, J = 14.4, 7.6 Hz, 1H), 4.43 (dt, J = 7.6, 5.2 Hz, 1H), 1.49 (s, 9H).Intermediate G: Benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate

[0177]

[0178] Step 1 : (R,E)-1-(2,4-dimethoxypheny)-N-((2,2-dimethyl-1,3-dioxolan-4-yl)methylene)methanamine. Prepared according to the procedure described by Hubschwerlen, C. and Schmid, G. Helv. Chim. Acta 1983, 66, 2206-2209 with the addition of MgSO 4 . To a suspension of (S)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde (Carbosynth LLC, 346 g, 43% in DCM, 1.143 mol) and MgSO 4 (278 g) in DCM (1.5 L) at 0 °C was added 2,4-dimethoxybenzylamine (193 g, 1.154 mol) over 20 min. After stirring at rt for 2 h it was filtered, washing the filter cake with DCM (2 x 250 mL). The mother liquor was used directly in step 2.

[0179] Step 2: 2-((2S,3S)-1-(2,4-dimethoxybenzy))-2-((R)-2,2-dimethy)-1,3-dioxolan-4-yl)-4-oxoazetidin-3-yl)isoindoline-1,3-dione. Prepared according to the procedure described by Hubschwerlen, C. and Schmid, G. Helv. Chim. Acta 1983, 66, 2206-2209. After addition of TEA (322 mL, 2.31 mol) to the crude mother liquor from step 1, it was cooled to 0 °C followed by addition of a solution of 2-(1,3-dioxoisoindolin-2-yl)acetyl chloride (284.3 g, 1.272 mol) in DCM (1 L) over a period of 30 min. The mixture was allowed to warm to rt and stirred for an additional 16 h, whereupon it was washed with water (2 x 1 L), saturated NaHCO 3 (aq, 1 L), brine (1 L), dried over Na 2 SO 4 and concentrated in vacuo, affording the crude title compound (631 g, assumed quantitative) as a pale yellow solid. The 1< H NMR of a purified sample (EtOAc-Heptane, 40-60%) was an identical match to literature reported data.

[0180] Step 3: (3S,4S)-3-amino-1-(2,4-dimethoxybenzy)-4-((R)-2,2-dimethy)-1,3-dioxolan-4-yl)azetidin-2-one. To a solution of crude 2-((2S,3S)-1-(2,4-dimethoxybenzyl)-2-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-oxoazetidin-3-yl)isoindoline-1,3-dione (631 g, 1.143 mol, assumed quantitative conversion from step 2) in EtOH (8.2 L) was added hydrazine hydrate (235 mL, 50-60%, ∼4 mol) over 20 min. The resulting mixture was heated to reflux for 3 h, cooled to rt, filtered, washed with EtOH and concentrated in vacuo. The residue was slurried in EtOAc (4 L), filtered and washed with water (2 x 1 L).

[0181] Step 4: Benzyl ((2S,3S)-1-(2,4-dimethoxybenzy)-2-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-oxoazetidin-3-yl)carbamate . To the crude organic solution from step 3 (EtOAc, 4 L) cooled to 0 °C was added saturated NaHCO 3 (aq, 2.05 L) followed by benzyl chloroformate (205 mL, 1.43 mol), drop-wise over 1 h. After stirring at rt for 2 h the layers were separated and the aqueous layer was extracted with EtOAc (2 x 50 mL). The combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was treated with MeOH (2 L), filtered and washed with MeOH (2 x 200 mL) to afford pure title compound (155 g) as a white solid. The mother liquor was cooled to-20 °C for 12 h and the resulting precipitate was collected by filtration, affording additional title compound (90 g) for a combined 45% yield over 4 steps. LCMS: m / z = 471.1 (M+1) .

[0182] Step 5: Benzyl ((2S,3S)-2-((R)-1,2-dihydroxyethyl-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate . To a solution of benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-oxoazetidin-3-yl)carbamate (267 g, 0.567 mol) in THF (3 L) was added a solution of TsOH•H 2 O (43.6 g, 0.229 mol) in water (0.75 L). The bilayer was heated to 70 °C for 16 h then cooled to rt, neutralized to pH = 7 with saturated NaHCO 3 (aq) and concentrated in vacuo. The resulting mixture was filtered, washed with water and dried to afford the title compound (240 g, 98%) as a pale yellow solid. LCMS: m / z = 431.1 (M+1).

[0183] Step6: Benzyl ((2S,3S)-1-(2,4-dimethoxybenzy))-2-formyl)-4-oxoazetidin-3-yl)carbamate. To a solution of benzyl ((2S,3S)-2-((R)-1,2-dihydroxyethyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate (240 g, 0.557 mol) in EtOAc (4.5 L) was added a solution of sodium periodate (132 g, 0.617 mol) in water (1.125 L) and the bilayer was heated to 50 °C for 2 h, whereupon it was cooled to rt and the layers were separated. The aqueous layer was extracted with EtOAc (500 mL) and the combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (218 g, 98%) as a pale yellow solid. LCMS: m / z = 399.0 (M+1). 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.32 (d, J = 3.2 Hz, 1H), 8.19 (d, J = 8.5 Hz, 1H), 7.39-7.23 (m, 5H), 7.16 (d, J = 8.3 Hz, 1H), 6.53 (d, J = 2.4 Hz, 1H), 6.47 (dd, J = 8.3, 2.4 Hz, 1H), 5.00-4.96 (m, 2H), 4.90 (dd, J = 8.5, 5.8 Hz, 1H), 4.38 (d, J = 14.5 Hz, 1H), 4.29 (d, J = 14.5 Hz, 1H), 4.05 (dd, J = 5.9, 3.3 Hz, 1H), 3.73 (s, 3H), 3.70 (s, 3H).

[0184] Step7: Benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate. To a solution of benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-formyl-4-oxoazetidin-3-yl)carbamate (218 g, 0.546 mol) in a mixture of DCM:MeOH (4:1, 2.25 L) at 0 °C was added sodium borohydride (41.3 g, 1.09 mol), portion-wise. The resulting mixture was stirred at 0 °C for 2 h, whereupon it was quenched with cold water (1 L) for 30 min and the layers were separated. The aqueous layer was extracted with DCM (3 x 200 mL) and the combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (208 g, 95%) as an off white solid. LCMS: m / z = 401.2 (M+1); 1< H NMR (300 MHz, CDCl 3 ) δ 7.37-7.29 (m, 5H), 7.21-7.18 (m, 1H), 6.46-6.49 (m, 2H), 5.82 (bd, J = 9.6 Hz, 1H), 5.18-5.08 (m, 3H), 4.45 (d, J = 14.4 Hz, 1H), 4.28 (d, J = 14.4 Hz, 1H), 3.83 (s, 3H), 3.79 (s, 3H), 3.76-3.72 (m, 1H), 3.63-3.52 (m, 2H), 1.87 (dd, J = 9.6, 4.0 Hz, 1H).Intermediate H: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate

[0185]

[0186] Step1: Benzyl ((2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate. Prepared according to Mastalerz et al. J. Med. Chem. 1988, 31, 1190. To a solution of intermediate G (208 g, 0.529 mol) in ACN (4 L) was added potassium persulfate (243 g, 0.899 mol) followed by a solution of dipotassium phosphate (147.4 g, 0.846 mol) in water (2 L). The resulting mixture was heated to 90 °C for 4 h then cooled to rt and concentrated in vacuo, removing most of the ACN. The mixture was extracted with EtOAc (1 L, 2 x 200 mL) and the combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Hexanes, 50-100%), affording the title compound (86g, 65%) as a white solid. Analytical data was an identical match to that reported in the literature.

[0187] Step 2: (2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-amonium acetate. To a solution of benzyl ((2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate (25 g, 100 mmol) in MeOH (350 mL) was added Pd on C (10% wet, 2.5 g) followed by AcOH (11.4 mL, 200 mmol). The mixture was evacuated and recharged with H 2 (3x), bringing the final pressure to 50 psi. It was stirred at rt for 2 h, then discharged, filtered over celite and concentrated in vacuo, affording the crude title compound (22 g) as a light brown oil, which was used directly in step 3.

[0188] Step 3: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazol)-4-y))-2-(((2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a solution of (Z)-tert-butyl 2-(((2-(benzo[d]thiazol-2-ylthio)-1-(2-((tert-butoxycarbonyl)amino)-thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (85 g, 116.4 mmol) in DMF (200 mL) at 0 °C was added a solution of (2S,3S)-2-(hydroxymethyl)-4-oxoazetidin-3-amonium acetate (22 g, 100 mmol, assumed quantitative from step 2) in DMF (100 mL) followed by DIPEA (52.2 mL, 300 mmol). The mixture was allowed to warm to rt and stirred for an additional 16 h, whereupon it was concentrated in vacuo and purified via silica gel chromatography (EtOAc-Hexanes, 25-100%), affording the crude title compound (44 g, 83%) as a pale yellow solid. LCMS: m / z = 526.1 (M-1); 1< H NMR (400 MHz, CDCl 3 ):δ 8.94 (s, 1H), 8.02 (d, J = 7.8 Hz, 1H), 7.30 (s, 1H), 6.48 (s, 1H), 5.43 (dd, J = 7.4, 4.7 Hz, 1H), 4.25 (m, 1H), 4.02 (dd, J = 8.6, 4.3 Hz, 1H), 3.86 (m, 2H), 1.56 (s, 3H), 1.55 (s, 3H), 1.52 (s, 9H), 1.44 (9H, s).Intermediate I: (Z)-tert-Butyl 2-(((2-(benzo[d]thiazol-2-ylthio)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate

[0189] To a suspension of (Z)-2-(((1-(fert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (50 g, 116.4 mmol) and 2,2'-dibenzothiazolyl disulfide (54.2 g, 163 mmol) in DCM (1 L) was added triphenylphosphine (44.3 g, 168.8 mmol) followed by drop-wise addition of TEA (22.7 mL, 163 mmol). After stirring for 16 h, the mixture was concentrated and used directly in the preparation of intermediate H. LCMS: m / z = 579.0 (M+1).Intermediate J: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(azidomethyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate

[0190]

[0191] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2S,3S)-2-(iodomethyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a solution of intermediate H (44.0 g, 83.4 mmol), triphenylphosphine (43.7 g, 166.8 mmol) and imidazole (11.4 g, 166.8 mmol) in DCM was added iodine (42.3 g, 166.8 mmol) portion-wise over 5 min. After stirring at rt for 16 h it was diluted with DCM (300 mL), washed with saturated Na 2 S 2 O 3 (aq, 200 mL), water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via column chromatography (EtOAc-Hexanes, 25-75%), affording the title compound (33 g, 62%) as a yellow solid. LCMS: m / z = 638.0 (M-1). 1< H NMR data was an identical match to that described in WO2012073138(A1).

[0192] Step 2: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(azidomethyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2S,3S)-2-(iodomethyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (24.0 g, 37.6 mmol) in THF (200 mL) at 0 °C was added TEA (10.5 mL, 75.2 mmol) followed by tetrabutylammonium azide (13.9 g, 48.9 mmol). The mixture was allowed to warm to rt and stirred for an additional 16 h, whereupon it was poured into ice-water (200 mL) and extracted with EtOAc (3 x 100 mL). The combined organic layers were washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography, affording the title compound (17.0 g, 82%) as a pale yellow solid. LCMS: m / z = 551.0 (M-1). 1< H NMR data was an identical match to that described in WO2012073138(A1).Intermediate K: (2R,3S)-2-(azidomethyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1 - oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid

[0193]

[0194] To a solution of intermediate J (500 mg, 0.905 mmol) in DMF (8 mL) was added SO 3 ·DMF (1.38 g, 9.05 mmol). After stirring at rt for 4h, it was diluted with EtOAc (50 mL) and washed with water, followed by brine until pH = 7. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (500 mg, 87%) as a light yellow solid. LCMS: m / z = 629.85 (M-1) ; 1< H NMR (400 MHz, DMSO-d 6 ) δ 11.85 (s, 1H), 9.10 (d, J = 8.9 Hz, 1H), 8.63 (s, 1H), 7.27 (d, J = 11.1 Hz, 1H), 6.55 (s, 1H), 5.37-5.13 (m, 1H), 3.83 - 3.54 (m, 2H), 1.46 - 1.41 (m, 4H), 1.43 - 1.35 (m, 7H).Intermediate L: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(aminomethyl)-4-oxoazetidin-3-y))amino)-1-(2-((tert-butoxycarbony))amino)thiazo)-4-y))-2-oxoethy)idene)amino)oxy)-2-methylpropanoate

[0195]

[0196] To a solution of intermediate J (17.0 g, 30.8 mmol) in EtOH (300 mL) was added Pd on C (10%, wet, 2.0 g) under nitrogen. The mixture was evacuated and recharged with H 2 (3x), bringing the final pressure to 50 psi. It was stirred at rt for 2 h, then discharged, filtered over celite and concentrated in vacuo, affording the crude title compound (15.5 g, 96%) as a pale yellow solid. LCMS: m / z = 527.1 (M-1). 1< H NMR data was an identical match to that described in WO2012073138(A1).Intermediate M: tert-Butyl 4-(but-3-yn-1-yl)piperazine-1-carboxylate

[0197]

[0198] To a solution of 1-Boc-piperazine (0.5 g, 2.68 mmol) in acetonitrile (2.5 mL) was added K 2 CO 3 (0.55 g, 4.02 mmol) followed by 4-bromo-1-butyne (0.39 g, 2.95 mmol). The mixture was heated at 60 °C for 6 h, allowed to come to room temperature, diluted with water and extracted with EtOAc (2 x 15 mL). The combined organic layers washed with water, brine, dried over Na 2 SO 4 and concentrated under vacuo to afford the title compound (0.55 g, 86%); LCMS: m / z = 239.10 (M+1). Method 2minLowp.Intermediate N: N,N,N-Trimethyl-2-oxo-2-(prop-2-yn-1-ylamino)ethanaminium bromide

[0199]

[0200] Step 1: 2-Bromo-N-(prop-2-yn-1-yl)acetamide To a solution of bromoacetyl bromide (2.1 g, 10.34 mmol) and triethylamine (1.5 mL, 10.34 mmol) in DCM (20 mL) cooled to 0 °C, was added a solution of propargylamine (0.57 g, 10.34 mmol) in DCM (10 mL) drop-wise over a period of 5 min, maintaining stirring throughout. The mixture was stirred at 0 °C for 2 h, whereupon the solids were filtered and the filtrate was concentrated in vacuo. The crude residue was purified via column chromatography (60-120 mesh silica, 50% EtOAc: Hexane), affording the title compound (1.3 g, 72%) as an off white solid; LCMS: m / z = 176.2 (M+1) ; 1< H NMR (300 MHz, CDCl 3 ) δ 6.68 (brs, 1H), 4.09 (dd, J = 5.4, 2.6 Hz, 2H), 3.90 (s, 2H), 2.28 (t, J = 2.6 Hz, 1H).

[0201] Step 2: N,N,N-Trimethyl-2-oxo-2-(prop-2-yn-1-ylamino)ethanaminium bromide. To a solution of 2-bromo-N-(prop-2-yn-1-yl)acetamide (0.6 g, 3.4 mmol) in acetonitrile (5 mL) was added trimethylamine (30% in MeOH, 5 mL). The mixture was stirred at room temperature for 16 h and concentrated in vacuo. The resulting residue was triturated with ether, resulting in the title compound (780 mg, 97%); LCMS: m / z = 155.1 (M+1) ; 1< H NMR (300 MHz, DMSO-d 6 ) δ 9.03 (t, J = 5.3 Hz, 1H), 4.17 (s, 2H), 3.95 (dd, J = 5.4, 2.6 Hz, 2H), 3.23 (s, 9H), 2.09 (s, 1H).Intermediate O: 2-(4-methylpiperazin-1-yl)-N-(prop-2-yn-1-yl)acetamide

[0202]

[0203] To a solution of 2-bromo-N-(prop-2-yn-1-yl)acetamide (0.7 g, 3.98 mmol) in DCM (10 mL) added N-methyl piperazine (0.66 mL, 5.96 mmol) drop wise. Reaction mixture stirred at rt for 16 h, diluted with DCM and washed with water and brine. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was triturated with ether-pentane, affording the title compound (0.38 g, 49%); LCMS: m / z = 196.15 (M+1); 1< H NMR (300 MHz, DMSO-d 6 ) δ 8.06 (d, J = 6.1 Hz, 1H), 3.86 (dd, J = 5.9, 2.5 Hz, 2H), 3.07 (t, J = 2.5 Hz, 1H), 2.91 (s, 2H), 2.47-2.25 (m, 8H), 2.15 (s, 3H).Intermediate P: 4-Ethynyl-1-methylpyridin-1-ium trifluoromethanesulfonate

[0204]

[0205] Prepared according to Rubinsztajn et al. Tetrahedron Lett. 1992, 33, 14, 1821-1824. To a suspension of 4-ethynylpyridine hydrochloride (500 mg, 3.58 mmol) in DCM (50 mL) at 0 °C was slowly added NaHCO 3 solution (aq, satd, 10 mL). After stirring for 5 min, the layers were separated and the aqueous was extracted with DCM (2 x 10 mL). The combined organic layers were dried over Na 2 SO 4 , concentrated in vacuo and subjected to high vacuum for 10 min. The crude residue was dissolved in DCM (10 mL), cooled to 0 °C and methyl triflate (450 µL, 3.94 mmol) was added drop-wise. After stirring for 30 min at 0 °C, ether was added and the precipitate was collected and dried, affording the title compound (870 mg, 91%) as a light brown solid. Analytical data was identical to literature reported values.Intermediate Q: 4-Ethynyl-1,3-dimethylpyridin-1-ium trifluoromethanesulfonate

[0206]

[0207] Step 1: 3-Methyl-4-((trimethylsilyl)ethynyl)pyridine. To a solution of 4-bromo-3-methyl pyridine hydrochloride (5.0 g, 24.0 mmol) in THF (degassed, 80 mL) was added copper iodide (450 mg, 2.40 mmol) and triethylamine (20.0 mL, 143.9 mmol). After degassing for 15 min, palladium tetrakis triphenylphosphine (830 mg, 0.72 mmol) and trimethylsilylacetylene (6.10 mL, 43.16 mmol) were added. The mixture was heated at 50 °C for 16 h then cooled to rt and filtered. The crude residue was purified via silica gel chromatography (EtOAc-Hexanes, 10%) to afford the title compound (3.95 g, 87%) as clear but dark oil.

[0208] Step 2: 4-Ethynyl-3-methylpyridine. Prepared according to the method described in WO2013 / 028590. To a solution of 4-ethynyl-3-methylpyridine (3.79 g, 20 mmol) in THF (50 mL) was added TBAF (1M in THF, 40 mL, 40 mmol). After stirring at rt for 1 h, the solution was concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Hexanes, 20-40%) affording the title compound (1.70 g, 72%) as an off white solid.

[0209] Step 3: 4-Ethynyl-1,3-dimethylpyridin-1-ium trifluoromethanesulfonate Prepared according to Rubinsztajn et al. Tetrahedron Lett. 1992, 33, 14, 1821-1824. To a solution of 4-ethynyl-3-methylpyridine (420 mg, 3.58 mmol) in DCM (10 mL) at 0 °C was added methyl triflate (450 µL, 3.94 mmol), drop-wise. After stirring for 30 min at 0 °C, ether was added and the precipitate was collected and dried, affording the title compound (863 mg, 86%) as a light brown solid.Intermediate R: tert-Butyl ((2H-1,2,3-triazol-4-yl)methyl)carbamate

[0210]

[0211] To a solution of N-Boc-propargyl amine (1.60 g, 10.3 mmol) in a mixture of DMF:MeOH (4:1, 10 mL) was added trimethylsilylazide (2.0 mL, 15.2 mmol) and Cul (95 mg, 0.50 mmol). The resulting mixture was heated to 100 °C for 16 h, whereupon it was concentrated in vacuo and purified via silica gel chromatography, affording the title compound (2.0 g, 99%) as a light yellow oil; LCMS: m / z = 196.9 (M-1) .Intermediate S:

[0212]

[0213] Step 1: Benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(iodomethyl)-4-oxoazetidin-3-yl)carbamate. To a solution of intermediate G (10 g, 25 mmol), triphenylphosphine (19.6 g, 75 mmol) and imidazole (5.1 g, 75 mmol) in DCM (150 mL) at 0 °C was added iodine (19 g, 75 mmol) portion-wise over 10 min. After stirring at rt for 4 h, it was washed with saturated Na 2 S 2 O 3 (aq) solution, water, brine, dried over Na 2 SO 4 anc concentrated in vacuo. The crude residue was suspended in EtOAc (150 mL) and stirred for 16 h whereupon it was filtered then washed with acetone and MeOH, affording the title compound (9.8 g, 77%) as a white solid. LCMS: m / z = 510.8 (M+1).

[0214] Step 2: Benzyl ((2R,3S)-2-(azidomethyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate. To a solution of benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(iodomethyl)-4-oxoazetidin-3-yl)carbamate (5.00 g, 9.80 mmol) in THF (100 mL) at 0 °C was added TEA (2.73 g, 19.6 mmol) followed by a solution of tetrabutylammonium azide (3.62 g, 12.7 mmol) in THF. After stirring at rt for 16 h, it was filtered and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 2%), affording the title compound (3.4 g, 81%) as a white solid.

[0215] Step 3: To a solution of benzyl ((2R,3S)-2-(azidomethyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate (3.00 g, 7.06 mmol) in DCM (6 mL) was added DMSO: water: tert-butanol (1:1:1,6 mL) tert-butyl but-3-yn-1-ylcarbamate (2.19 g, 14.1 mmol), CuSO 4 (56 mg, 0.35 mmol) and sodium L-ascorbate (2.01 mg, 10.6 mmol). After stirring at rt for 3 h the mixture was partially concentrated and water was added, whereupon the solids were collected by filtration. The filter cake was suspended in DCM, filtered and the filtrate concentrated, affording the title compound (assumed quantitative) as a light yellow solid.

[0216] Step 4: To a solution of the product from step 3 (7.06 mmol) in ACN (50 mL) was added potassium persulfate (3.82 g, 14.1 mmol) followed by a solution of dipotassium phosphate (3.08 g, 17.7 mmol) in water (25 mL). The resulting mixture was heated to 90 °C for 4 h then cooled to rt, filtered and concentrated in vacuo, removing most of the ACN. The filtrate was extracted with EtOAc and concentrated in vacuo. The crude residue washed with hexanes and acetone, affording the title compound (1.72 g, 57% over 2-steps) as a white solid. LCMS: m / z = 431.1 (M+1).Intermediate T

[0217]

[0218] Step 1: The general procedure for the Mitsunobu reaction was followed. To a solution of intermediate G (5.00 g, 12.5 mmol), tert-butyl ((2H-1,2,3-triazol-4-yl)methyl)carbamate (2.97 mg, 15.0 mmol), triphenylphosphine (3.93 mg, 15.0 mmol) and DIAD (3.0 mL, 15 mmol) in THF (100 mL). Purified via silica gel chromatography (MeOH-DCM, 2-5%), affording the title compound (12.6 g, contaminated with triphenylphosphine oxide) as a white foam.

[0219] Step 2: To a solution of the product from step 1 (12.5 mmol) in ACN (150 mL) was added a solution of potassium persulfate (6.76 g, 25.0 mmol) and dipotassium phosphate (5.44 g, 31.2 mmol) in water (75 mL). The resulting mixture was heated to 90 °C for 4 h then cooled to rt, diluted with water and extracted with EtOAc. The organic layer was concentrated in vacuo and the crude residue was purified via silica gel chromatography, affording the title compound (2.23 g, 41% over 2-steps) as a white solid. LCMS: m / z = 428.9 (M-1).Intermediate U:

[0220]

[0221] Step 1 : Benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((1,3-dioxoisoindo)in-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate. The general procedure for the Mitsunobu reaction was followed using intermediate G (5.00 g, 12.5 mmol), phthalimide (1.83 g, 12.5 mmol), triphenylphosphine (3.93 g, 15.0 mmol), DIAD (3.03 g, 15.0 mmol) and THF (150 mL). After stirring for 16 h, the formed precipitate was filtered, affording title compound (5.67 g, 85%) as a white solid.

[0222] Step 2: Benzyl ((2R,3S)-2-(aminomethyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate. To a solution of benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((1,3-dioxoisoindolin-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate (4.40 g, 8.31 mmol) in DCM:MeOH (5:1, 60 mL) was added hydrazine hydrate (1.50 g, 25.0 mmol). After stirring for 16 h the precipitate was filtered off and the filtrate was concentrated, affording title compound (quantitative) as a white solid.

[0223] Step 3: To a solution of benzyl ((2R,3S)-2-(aminomethyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate (8.31 mmol) in DCM:MeOH (13:1, 43 mL) was added (R)-tert-butyl (oxiran-2-ylmethyl)carbamate. After stirring for 16 h it was concentrated in vacuo and purified via silica gel chromatography (MeOH-DCM, 2-10%), affording the title compound (2.2 g, 46%) as a white foam.

[0224] Step 4: To a solution of the product from step 3 (2.20 g, 3.85 mmol) in DCM (100 mL) at 0 °C was added CDI (1.12 g, 6.92 mmol). After stirring at 15 °C for 2 h the solution was concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 1-5%) to afford the title compound (2.10 g, 91%) as a white foam.

[0225] Step 5: To a solution of the product from step 4 (2.10 g, 3.51 mmol) in ACN (40 mL) was added a solution of potassium persulfate (1.89 g, 7.02 mmol) and dipotassium phosphate (1.52 g, 8.75 mmol) in water (20 mL). The resulting mixture was heated to 90 °C for 4 h then cooled to rt and filtered. The filtrate was concentrated, extracted with EtOAc and the organic layer was concentrated. The crude residue was purified via silica gel chromatography (MeOH-DCM, 2-5%), affording the title compound (660 mg, 42%) as a pale yellow solid. LCMS: m / z = 449.09 (M+1).Intermediate V:

[0226]

[0227] Step 1: (1H-1,2,3-triazol-4-yl)methanol. To a solution of propargyl alcohol (11.2 g, 200 mmol) in DMF (160 mL) and MeOH (40 mL) was added Cul (1.9 g, 10 mmol) and trimethylsilyl azide (34.6 g, 300 mmol). After heating to 100°C for 16 h, the reaction mixture was cooled to rt and filtered through celite. The filtrate was concentrated in vacuo to afford the title compound (assume quantitative). The crude compound was used as such in the following step.

[0228] Step 2: 4-(((tert-butyldimethylsilyl)oxy)methyl)-1H-1,2,3-triazole. To a solution of (1H-1,2,3-triazol-4-yl)methanol (30 g, 200 mmol) in DCM (160 mL) was added imidazole (20.4 g, 300 mmol) followed by TBDMS-Cl (33.3 g, 220 mmol) as a solid in portions. After stirring at rt for 16 h, the reaction mixture was filtered through celite, and the filtrate was concentrated in vacuo. The residue was dissolved in EtOAc (500 mL) and washed with water, brine, dried over Na 2 SO 4 , and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-hexanes, 5-30%) to afford the title compound (30.2 g, 71%) as a pale yellow solid.

[0229] Step 3: Benzyl ((2R,3S)-2-((4-(((tert-butyldimethylsilyl)oxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate . To a solution of benzyl ((2S,3S)-1-(2,4-dimethoxybenzyl)-2-(hydroxymethyl)-4-oxoazetidin-3-yl)carbamate (0.94 g, 2.34 mmol), 4-(((tert-butyldimethylsilyl)oxy)methyl)-1H-1,2,3-triazole (0.5 g, 2.34 mmol), and PPh 3 (0.74 g, 2.81 mmol) in THF (20 mL) at 0°C was added DIAD (0.57 g, 2.81 mmol) slowly. After stirring at rt for 16 h, the reaction mixture was concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-hexanes, 20-30%) to afford the title compound (1.25 g, 89%) as a pale yellow solid. LCMS: m / z = 594.3 (M-1).

[0230] Step 4: Benzyl ((2R,3S)-2-((4-(((tert-butyldimethylsilyl)oxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate . To a solution of benzyl ((2R,3S)-2-((4-(((tert-butyldimethylsilyl)oxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate (1.25 g, 2.1 mmol) in CH 3 CN (20 mL) was added K 2 S 2 O 8 (0.73 g, 2.7 mmol) followed by a solution of K 2 HPO 4 (0.84 g, 4.8 mmol) in water (10 mL). After stirring at 90°C for 1 h, more K 2 S 2 O 8 (0.23 g, 0.84 mmol) was added. After heating at 90°C for additional 2 h, the reaction mixture was concentrated in vacuo. The residue was extracted with EtOAc (2 x 30 mL). Combined organic layers were washed with water, brine, dried with Na 2 SO 4 , filtered and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 1-3%) to afford the title compound (0.44 g, 47%) as a pale yellow solid. LCMS: m / z = 446.2 (M+1).

[0231] Step 5: Benzyl ((2R,3S)-2-((4-(hydroxymethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate. To a solution of benzyl ((2R,3S)-2-((4-(((tertbutyldimethylsilyl)oxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate (10.8 g, 24.4 mmol) in THF (100 mL) was added TBAF (1 M in THF, 26.6 mL, 26.6 mmol) slowly over a period of 15 min. After stirring at rt for 1.5 h, the reaction mixture was concentrated in vacuo. The crude residue was purifed via silica gel chromatography (MeOH-DCM, 1-5%) to afford the title compound (6.8 g, 85%) as a pale yellow solid. LCMS: m / z = 330.0 (M+1).

[0232] Step 6: (3S,4R)-3-amino-4-((4-(hydroxymethyl)-2H-1,2,3-triazol-2-yl)methyl)azetidin-2-one. To a solution of benzyl ((2R,3S)-2-((4-(hydroxymethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate (1.54 g, 4.65 mmol) in EtOH (50 mL) and EtOH (25 mL) was added Pd / C (10%, 0.51 g, 4.65 mmol). After stirring at rt for 4h, the reaction mixture was filtered through a celite pad, and the filtrate was concentrated in vacuo to afford the title compound (assume quantitive). The crude was used as such in the following step. LCMS: R t = 0.12 min, m / z = 198.0 (M+1) Method 2m_acidic.Intermediate W: 3-(ammoniomethyl)-1-methylpyridin-1-ium chloride

[0233]

[0234] Step1: N-(pyridin-3-ylmethyl)acetamide Prepared according to Plater et al. Org. Biomol. Chem. 2009, 7, 1633. To a solution of pyridin-3-ylmethanamine (9.42 ml, 92 mmol) in water (103 ml) at 10°C was added acetic anhydride (10.47 ml, 111 mmol), stirred at a rate where the internal temperature did not rise above 25°C. After an additional 18 h of stirring, the solution was concentrated in vacuo then co-evaporated with toluene (3x) to afford the title compound (14.22 g, quantitative) as a clear oil. LCMS: R t =0.12 min, m / z = 151.1 (M+1) Method 2m_acidic. 1< H NMR (400 MHz, CDCl 3 ) δ 8.49 (d, J = 2.4 Hz, 2H) 7.65 (dd, J = 7.8, 1.6 Hz, 1H) 7.30-7.24- (m, 1 H) 6.59-6.49 (m, 1 H) 4.43 (d, J = 6.0 Hz, 2H) 2.02 (s, 3H).

[0235] Step 2: 3-(acetamidomethyl)-1-methylpyridin-1-ium iodide To a solution of N-(pyridin-3-ylmethyl)acetamide (13.89 g, 92 mmol) in DCM at 0°C was added methyl iodide (8.10 mL, 129 mmol). The cooling bath was removed after 10 min and the solution was stirred at rt for 19 h, whereupon it was concentrated in vacuo and used as crude in step 3. LCMS: R t = 0.18 min, m / z = 164.9 (M+) Method 2m_acidic. 1< H NMR (400 MHz, DMSO-d 6 ) δ 8.91-8.87 (m, 2H) 8.58 (brs, 1H)8.42 (d, J = 8.0 Hz, 1H)8.09 (t, J = 7.0 Hz, 1H) 4.43 (d, J = 5.9 Hz, 2H) 4.35 (s, 3H) 1.92 (s, 3H)

[0236] Step 3: 3-(ammoniomethyl)-1-methylpyridin-1-ium chloride A suspension of 3-(acetamidomethyl)-1-methylpyridin-1-ium iodide (26.9 g, 92 mmol) in HCl (6N, 307 mL, 1.84 mol) was heated to 100 °C for 3h. The solution was concentrated under reduced pressure (bath temp 80°C). The resulting red oil solidified overnight and was triturated with MeOH and filtered to afford the title compound (8.76 g, 49%) as an off white solid. The filtrate was concentrated to a red oil, which after standing for 4 days, the formed solid was collected and washed with cold MeOH, affording a second crop (6.5 g, 36%). LCMS: R t = 0.11 min, m / z = 123.0 (M+) Method 2m_acidic. 1< H NMR (400 MHz, DMSO-d 6 ) δ ppm 9.18 (s,1H) 9.03 (d, J = 6.0 Hz, 1H)8.66 (d, J = 8.1 Hz, 1H) 8.45 (br s, 3H) 8.24 (t, J = 7.0 Hz, 1H) 4.38 (s, 3H) 4.30 (s, 2H).

[0237] The Intermediates described above, and similar compounds made by the same methods, can be used to prepare compounds of Formula (I) by the synthesis schemes provided herein. The following Examples illustrate synthesis of selected compounds of Formula (I) and provide methods that can be adapted to synthesis of other compounds of Formula (I).Example 1. 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0238] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate. A solution of Intermediate L (100 mg, 0.190 mmol), methyl-4-bromobutyrate (25 µL, 0.194 mmol) and TEA (27 µL, 0.194 mmol) in DMF (1.3 mL) was heated to 70 °C for 16 h while stirring, whereupon the heat was then raised to 90 °C. After 6 h of additional heating it was diluted with HCI (1N) and EtOAc. The aqueous layer was extracted with EtOAc (2x) and the combined organic layers were washed with LiCI soln (5% aq), brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Heptane, 50-100% then MeOH-EtOAc, 0-7%), affording the title compound (21 mg, 18%) as a foam. LCMS: R t = 0.88 min, m / z = 595.4 (M+1) Method 2m_acidic.

[0239] Step 2: (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)azetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (43 mg, 0.072 mmol) in DMF (725 µL) was treated with SO 3 ·DMF (111 mg, 0.725 mmol). The solution was stirred at rt for 30 min then diluted with EtOAc and poured into LiCI solution (5% aq). The aqueous was extracted with EtOAc (2x) and the combined organic layers were washed with brine, dried over Na 2 SO 4 and concentrated in vacuo, affording the crude title compound (55 mg) as a white solid. LCMS: Rt = 0.77 min, m / z = 675.3 (M+1) Method 2m_acidic. It was used in step 3 without further purification.

[0240] Step 3: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0241] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopyrrolidin-1-yl)methyl)azetidine-1-sulfonic acid (55 mg, 0.072 mmol), DCM (720 µL) and TFA (333 µL, 4.32 mmol). The crude residue was purified by reverse phase preparative HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (6 mg, 16%) as a white solid. LCMS: R t = 0.35 min, m / z = 519.0 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O): δ 7.17 (s, 1H), 5.46 (d, J = 5.8 Hz, 1H), 4.71-4.64 (m, 1H), 3.92 (dd, J = 14.7, 8.7 Hz, 1H), 3.71-3.55 (m, 2H), 3.49 (dd, J = 14.7, 4.1 Hz, 1H), 2.42 (td, J = 8.0, 4.8 Hz, 2H), 2.08 (p, J = 7.6 Hz, 2H), 1.55 (s, 3H), 1.54 (s, 3H).Example 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0242] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazol-4-yl)-2-(((2R,3S)-2-(((2-((tert-butyldimethylsilyl)oxy)ethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. A solution of Intermediate L (500 mg, 0.949 mmol) and (2-bromoethoxy)(tert-butyl)dimethylsilane (204 µl, 0.949 mmol) in ACN (3.2 mL) was heated at 80°C in a microwave for 30 min then kept at rt for 12 h. It was reheated to 100°C for 45 min in the microwave then kept at rt for 12 h, whereupon it was diluted with EtOAc and washed with sodium carbonate (2 M, aq), dried over sodium sulfate and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Heptane, 0-100% then MeOH-DCM, 10%) to afford the title compound (111 mg, 17%). LCMS: R t = 1.03 min, m / z = 685.4 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, CDCl 3 ) δ 8.17 (d, J = 8.4 Hz, 1H), 7.30 (s, 1H), 6.30 (br s, 1H) 5.57-5.50 (m, 1H) 4.09-4.01 (m, 1H) 3.77-3.61 (m, 3H) 3.09 (dd, J = 12.6, 3.7 Hz, 1H) 2.87-2.71 (m, 3H) 1.56 (s, 6H) 1.53 (s, 9H) 1.44 (s, 9H) 0.86 (s, 9H) 0.03 (s, 3H), 0.03 (s, 3H).

[0243] Step 2: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-(((2-hydroxyethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. Prepared according to Seki et al. Synlett 1995, 609-611. To a solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-(((2-((tert-butyldimethylsilyl)oxy)ethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (111 mg, 0.162 mmol) in DMF:NMP (2.7:1, 1.62 mL) was added ammonium fluoride hydrofluoride (37.0 mg, 0.648 mmol). After stirring for 65 h, the solution was diluted with water and extracted with EtOAc. The organic layer was dried over sodium sulfate and concentrated in vacuo to afford crude title compound (92 mg, 99%). The crude material was used directly in step 3. LCMS: R t = 0.76 min, m / z 571.3 (M+1) Method 2m_acidic.

[0244] Step 3: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate. Prepared according to PCT Int. Appl. 2011061760. A solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-(((2-hydroxyethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (92 mg, 0.161 mmol) in Chloroform (806 µl) was treated with CDI (131 mg, 0.806 mmol) After stirring at rt for 3h it was diluted with EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified by silica gel chromatography (MeOH-DCM, 0-10%), affording the title compound (91 mg, 95%) as an orange oil. LCMS: R t = 0.86 min, m / z = 597.2 (M+1) Method 2m_acidic.

[0245] Step 4: (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid . A solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (91 mg, 0.153 mmol) in DMF (Volume: 763 µl) was treated with SO 3 ·DMF (234 mg, 1.525 mmol). After stirring at rt for 1 h it was diluted with EtOAc, washed with brine (3 x), dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (100 mg, 97%) as an orange solid. LCMS: R t = 0.78 min, m / z = 677.3 (M+1) Method 2m_acidic.

[0246] Step 5: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid .

[0247] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid (100 mg, 0.148 mmol), DCM (1.5 mL) and TFA (569 µl, 7.39 mmol). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (10 mg, 12%) as a white solid. LCMS: R t = 0.32 min, m / z = 521.0 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.33 (d, J = 8.8 Hz, 1H), 6.89 (s, 1H), 5.22 (dd, J = 8.8, 5.7 Hz, 1H), 4.23-4.11 (m, 3H), 3.75-3.62 (m, 2H assumed; obscured by water), 3.60-3.51 (m, 1H assumed; obscured by water), 3.34 (dd, J = 14.6, 5.5 Hz, 1H), 1.44 (s, 3H), 1.40 (s, 3H).Example 3: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0248] Step 1: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(((2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)ethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. A solution of Intermediate L (650 mg, 1.234 mmol) and (9H-fluoren-9-yl)methyl (2-oxoethyl)carbamate (365 mg, 1.234 mmol) in DCE (12.3 ml) was treated with sodium triacetoxyborohydride (1.377 g, 6.17 mmol). After stirring at rt for 18 h it was quenched with saturated NaHCO 3 (aq) and extracted with EtOAc. The organic layer was washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-10%), affording the title compound (435 mg, 45%) as a white solid. LCMS: R t = 1.00 min, m / z = 792.3 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.11 (d, J = 9.0 Hz, 1H), 8.35 (s, 1H), 7.89 (d, J = 7.7 Hz, 2H), 7.67 (d, J = 7.5 Hz, 2H), 7.41 (t, J = 7.2 Hz, 2H), 7.32 (td, J = 7.4,1.2 Hz, 2H), 7.27 (s, 1H), 7.19 (t, J = 5.7 Hz, 1H), 5.20 (dd, J = 9.1, 5.0 Hz, 1H), 4.30 (d, J = 6.8 Hz, 2H), 4.24-4.17 (m, 1H), 3.76 (ddd, J = 8.8, 5.3, 3.7 Hz, 1H), 3.11-2.97 (m, 2H), 2.76 (dd, J = 12.5, 3.7 Hz, 1H), 2.63-2.52 (m, 3H), 1.45 (s, 9H), 1.42 (s, 3H), 1.39 (s, 3H), 1.38 (s, 9H).

[0249] Step 2: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(((2-aminoethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. A solution of tert-butyl 2-(((Z)-(2-(((2R,3S)-2-(((2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)ethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (435 mg, 0.549 mmol) in DMF (2.75 mL) was treated with piperidine (1.1 mL, 11 mmol). After stirring at rt for 1 h it was diluted with toluene and concentrated (3x). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (238 mg, 64%) as a white powder. LCMS: R t = 0.68 min, m / z = 570.3 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.12 (d, J = 8.9 Hz, 1H), 8.38 (s, 1H), 8.31 (s, 1H), 7.21 (s, 1H), 5.17 (dd, J = 8.3, 4.9 Hz, 1H), 3.76 (dt, J = 8.7,4.7 Hz, 1H), 2.81-2.51 (m, 6H), 1.44 (s, 9H), 1.41 (s, 3H), 1.39 (s, 3H), 1.38 (s, 9H).

[0250] Step 3: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate. To a solution of tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-(((2-aminoethyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (100 mg, 0.151 mmol) in chloroform (756 µl) was added CDI (98 mg, 0.604 mmol) followed by TEA (105 µl, 0.756 mmol). After stirring at rt for 1 h it was diluted with EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (73 mg, 81%) as a white solid. It was used as crude in step 4. LCMS: R t = 0.70 min, m / z = 596.2 (M+1) Method 2m_acidic.

[0251] Step 4: (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)azetidine-1-sulfonic acid. A solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (73 mg, 0.123 mmol) in DMF (613 µl) was treated with SO 3 ·DMF (94 mg, 0.613 mmol). After stirring at rt for 2 h it was diluted with EtOAc, washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (99 mg) as a white solid. LCMS: R t = 0.74 min, m / z = 676.3 (M+1) Method 2m_acidic.

[0252] Step 5: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0253] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxoimidazolidin-1-yl)methyl)azetidine-1-sulfonic acid (99 mg, 0.147 mmol), DCM (1.47 mL) and TFA (566 µl, 7.35 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-waterwith 0.1% formic acid modifier, 24 mL / min), affording the title compound (4.8 mg) as a white powder. LCMS: R t = 0.31 min, m / z = 520.0 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.25 (dd, J = 9.0, 5.0 Hz, 1H), 6.83 (s, 1H), 5.21 (dd, J = 9.0, 5.8 Hz, 1H), 4.06-4.00 (m, 1H), 3.65 (dd, J = 14.5, 4.7 Hz, 1H), 3.33-3.30 (m, 1H assumed; obscured by water), 3.25 (dd, J = 14.5, 6.9 Hz, 2H assumed; obscured by water), 3.17 (ddd, J=16.7, 8.6, 6.7 Hz, 2H), 1.43 (s, 3H), 1.42 (s, 3H).Reference Example 4: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0254] Step 1: A 75 mL pressure vessel was charged with Intermediate A (1.50 g, 3.13 mmol), intermediate B (1.108g, 4.70 mmol), K 2 CO 3 (1.733 g, 12.54 mmol), Nal (564 mg, 3.76 mmol) and DMF (10 mL) then heated to 70°C with stirring. After 3 h, more intermediate B (1.108g, 4.70 mmol), K 2 CO 3 (1.733 g, 12.54 mmol) and Nal (394 mg, 2.63 mmol) were added and heating was continued. After 8 h of total heating it was cooled to rt, diluted with EtOAc / brine and the layers were separated. The aqueous layer was extracted with EtOAc (2x) and the combined organic layers were washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was combined with another sample of identical scale and procedure and purified via silica gel chromatography (Acetone-DCM, 0-30%), affording the 2H-tetrazole isomer (2.15 g, 60%) and 1H-tetrazole isomer (443 mg, 12%) as white solids. A-LCMS: R t = 0.97 min, m / z = 582.3 (M+1) Method 2m_acidic; B-LCMS: R t = 0.93 min, m / z = 582.3 (M+1) Method 2m_acidic.

[0255] Step 2: Prepared according to Mastalerz et al. J. Med. Chem. 1988, 31, 1190. To a solution of 2H-tetrazole isomer (2.15 g, 3.70 mmol) from step 1 in ACN:water (2:1, 61.5 mL) was added K 2 S 2 O 8 (1.40 g, 5.18 mmol) followed by K 2 HPO 4 (837 mg, 4.81 mmol). The resulting mixture was heated to 90°C for 1.5 h, whereupon more K 2 S 2 O 8 (300 mg, 1.11 mmol) and K 2 HPO 4 (167 mg, 0.961 mmol) were added. After 3.5 h of additional heating at 90 °C, it was diluted with ACN and concentrated in vacuo, removing most of the ACN. The mixture was diluted with water / EtOAc and the layers separated. The aqueous layer was extracted with EtOAc (5x) and the combined orgnic layers were dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM, 50%), to afford the title compound (785 mg, 49%). LCMS: R t = 0.77 min, m / z = 432.3 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, ACN-d 3 ) δ 7.49-7.30 (m, 5H), 6.76 (br s, 1H), 6.55-6.41 (m, 1H), 5.85 (br s, 1H), 5.03-5.21 (m, 3H), 4.88-4.71 (m, 2H), 4.52-4.43 (m, 3H), 4.39-4.24 (m, 1H), 1.50-1.35 (m, 9H).

[0256] Step 3: tert-Butyl ((2-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2H-tetrazol-5-yl)methyl)carbamate. Prepared according to the procedure described in Malmström et al. Bioorg. Med. Chem. Lett. 2012, 22, 5293. A solution of compound from step 2 (785 mg, 1.819 mmol) in EtOAc:MeOH (5:1, 65 mL) was evacuated and backfilled with argon (2x) followed by addition of Pd on C (10%, 581 mg). The system was evacuated and backfilled with H 2 (3x). After 21 h of stirring, the mixture was filtered over celite, washing with MeOH, concentrated in vacuo, taken up on toluene and reconcentrated (3x). The crude residue was used as such in following step. LCMS: R t = 0.37 min, m / z = 298.3 (M+1) Method 2m_acidic.

[0257] Step 4: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate.

[0258] To a solution of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (938 mg, 2.18 mmol) in DCM:DMF (5:1, 8.5 mL) at 0 °C was added DIPEA (953 µL, 5.46 mmol) followed by HATU (830 mg, 2.18 mmol). To the resulting solution was added a solution of tert-butyl ((2-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2H-tetrazol-5-yl)methyl)carbamate (541 mg, 1.82 mmol) in DCM:DMF (5:1, 8.5 mL). The solution was stirred at rt for 1 h then concentrated in vacuo, dissolved in EtOAc and washed with brine. The aqueous layer was extracted with EtOAc and the combined organic layers were washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM, 30-50%), affording the title compound (897 mg, 70%) as a purple solid. LCMS: R t = 1.01 min, m / z = 709.3 (M+1) Method 2m_acidic.

[0259] Step 5: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-2H-tetrazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid.

[0260] tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (200 mg, 0.282 mmol) in DMF (2 mL) was treated with SO 3 ·DMF (432 mg, 2.82 mmol). The purple solution immediately became green. After 20 min of stirring, more SO 3 ·DMF (432 mg, 2.82 mmol) was added. After an additional 20 min, more SO 3 ·DMF (432 mg, 2.82 mmol) was added. After 20 min the solution was diluted with EtOAc / brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (185 mg, 83%). LCMS: R t = 0.91 min, m / z = 789.1 (M+1) Method 2m_acidic.

[0261] Step 6: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0262] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-2H-tetrazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid (185 mg, 0.234 mmol), DCM (2.34 mL) and TFA (1.08 mL, 14.06 mmol) for 1.5 h. The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-waterwith 0.1% formic acid modifier, 24 mL / min), affording the title compound (55.5 mg, 45%) as a white powder. LCMS: R t = 0.30 min, m / z = 533.0 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.34 (d, J = 8.8 Hz, 1H), 8.55 (br s, 3H), 7.34 (br s, 2H), 6.73 (s, 1H), 5.37 (dd, J = 8.7,5.5 Hz, 1H), 5.19-5.13 (m, 1H), 5.01-4.94 (m, 1H), 4.62-4.57 (m, 1H), 4.43-4.37 (m, 2H), 1.38 (s, 3H) 1.34 (s, 3H).Reference Example 5: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-(guanidinomethyl)-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0263]

[0264] To a solution of 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (20 mg, 0.038 mmol) and pyrazole-1-carboxamidine hydrochloride (11.6 mg, 0.079 mmol). in DMF (376 µL) was added DIPEA (26.2 µL, 0.150 mmol). After stirring at rt for 12h the solution was concentrated in vacuo. Toluene was added and it was reconcentrated (3x). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (11 mg, 45%) as a white powder. LCMS: R t = 0.31 min, m / z = 575.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 7.49-7.04 (m, 5H), 6.74 (br s, 1H), 5.26 (br s, 1H), 5.14-5.07 (m, 1H), 4.98-4.90 (m, 1H), 4.65 (br s, 2H), 4.59-4.52 (m, 1H), 1.36 (s, 3H), 1.34 (s, 3H).Reference Example 6: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-1H-tetrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0265] Step 1: Prepared in an analogous manner to Example 4, step 2 using the appropriate 1H-tetrazole isomer obtained in Step 1 in Example 4 (442 mg, 0.760 mmol), K 2 S 2 O 8 (288 mg, 1.064 mmol) and K 2 HPO 4 (172 mg, 0.988 mmol) in ACN:water (2:1, 12.6 mL) at 90 °C for 1.5 h. More K 2 S 2 O 8 (62 mg, 0.228 mmol) and K 2 HPO 4 (42 mg, 0.198 mmol) were added and it was heated for an additional 3.5 h then cooled to rt, diluted with ACN and concentrated in vacuo, removing most of the ACN. The mixture was diluted with water / EtOAc and the layers separated. The aqueous layer was extracted with EtOAc (5x) and the combined organic layers were dried over Na 2 SO 4 . The crude residue was purified via silica gel chromatography (Acetone-DCM, 50%), to afford the title compound (179 mg, 54%). LCMS: R t = 0.72 min, m / z = 432.3 (M+1) Method 2m_acidic.

[0266] Step 2: tert-Butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-tetrazol-5-yl)methyl)carbamate. Prepared in an analogous manner to example 4, step 3, using the product of Step 1 (179 mg, 0.415 mmol) and Pd on C (10%, 132 mg) in EtOAc:MeOH (10:1, 13.8 mL) for 21 h. The crude residue was used as such in following step. LCMS: R t = 0.37 min, m / z = 298.3 (M+1) Method 2m_acidic.

[0267] Step 3: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate.

[0268] Prepared in an analogous manner to example 4, step 3 using (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (214 mg, 0.498 mmol), DIPEA (953 µL, 5.46 mmol) and HATU (830 mg, 2.18 mmol) in DCM:DMF (5:1, 3.6 mL) at 0 °C followed by a solution of tert-butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-tetrazol-5-yl)methyl)carbamate (123 mg, 0.415 mmol) in DCM:DMF (4.3:1, 3.7 mL). After stirring at rt for 1h it was subjected to an identical workup then purified via silica gel chromatography (Acetone-DCM), affording the title compound (174 mg, 59%) as a light purple solid. LCMS: R t = 1.03 min, m / z = 709.2 (M+1) Method 2m_acidic.

[0269] Step 4 : (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-tetrazol-1-yl)methyl)-4-oxoazetidine-1-sulfonicacid.

[0270] Prepared in an analogous manner to example 4, step 4 using tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (100 mg, 0.141 mmol) and SO 3 ·DMF (216 mg, 1.41 mmol) in DMF (1.4 mL) for 20 min at rt. Subjected to identical workup to afford the title compound (100 mg, 89%). LCMS: R t = 0.91 min, m / z = 789.1 (M+1) Method 2m_acidic.

[0271] Step 5: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-1H-tetrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0272] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-tetrazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (100 mg, 0.126 mmol), DCM (1.26 mL) and TFA (584 µL, 7.58 mmol) for 1.5 h. The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-waterwith 0.1% formic acid modifier, 24 mL / min), affording the title compound (18.7 mg, 28%) as a white powder. LCMS: R t = 0.31 min, m / z = 533.2 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.21 (d, J = 8.8 Hz, 1H), 7.28 (s, 2H), 6.79 (s, 1H), 5.35 (dd, J = 8.8,5.8 Hz, 1H), 4.79-4.61 (m, 2H), 4.59-4.53 (m, 1H), 4.47-4.35 (m, 2H), 1.36 (br s, 6H).Reference Example 7: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0273] Step1, Compound 1: Benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate.

[0274] Step1, Compound 2: Benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate.

[0275] Prepared in an analogous manner to example 4, step 1 using Intermediate A (1.0 g, 2.1 mmol), 5-methyl-2H-tetrazole (527 mg, 6.27 mmol), K 2 CO 3 (1.44 g, 10.5 mmol), Nal (470 mg, 3.13 mmol) in DMF (10 mL) at 70 °C for 4 h. No further reagent addition was necessary. After cooling to rt it was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM), affording the title compound 1 (680 mg, 70%) and title compound 2 (221 mg, 23%) as solids. 1-LCMS: R t = 0.87 min, m / z = 467.2 (M+1) Method 2m_acidic; 2-LCMS: R t = 0.80 min, m / z = 467.2 (M+1) Method 2m_acidic.

[0276] Step 2: Benzyl ((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate. Prepared in an analogous manner to example 4, step 2 using benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((5-methyl-2H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate (202 mg, 0.433 mmol), K 2 S 2 O 8 (164 mg, 0.606 mmol) and K 2 HPO 4 (98 mg, 0.563 mmol) in ACN:water (2:1, 7.4 mL) at 90 °C for 1.5 h. More K 2 S 2 O 8 (35 mg, 0.13 mmol) and K 2 HPO 4 (20 mg, 0.11 mmol) were added and it was heated for an additional 30 min then cooled to rt then concentrated in vacuo. The mixture was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-10%), to afford the title compound (111 mg, 81%). LCMS: R t = 0.58 min, m / z = 317.2 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, CDCl 3 ) δ 7.43-7.30 (m, 5H), 6.34 (br s, 1H), 6.01 (br s, 1H), 5.28-5.21 (m, 1H), 5.20-5.12 (m, 3H), 4.92 (dd, J = 14.3, 3.9 Hz, 1H), 4.68 (dd, J = 14.2, 7.9 Hz, 1H), 4.48-4.27 (m, 2H), 2.53 (s, 3H).

[0277] Step 3: (3S,4R)-3-amino-4-((5-methyl-2H-tetrazol-2-yl)methyl)azetidin-2-one. Prepared in an analogous manner to example 4, step 3 using benzyl ((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)carbamate (111 mg, 0.351 mmol) and Pd on C (10%, 50 mg) in EtOAc:MeOH (5:1, 7.0 mL) for 3 h. The crude residue was used as such in following step. LCMS: R t = 0.14 min, m / z = 183.2 (M+1) Method 2m_acidic.

[0278] Step 4: tert-Butyl 2-(((Z)-(1 -(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. Prepared in an analogous manner to example 4, step 3 using (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (130 mg, 0.302 mmol), DIPEA (158 µL, 0.906 mmol) and HATU (138 mg, 0.362 mmol) in DCM:DMF (2:1, 3.0 mL) at 0 °C followed by a solution of (3S,4R)-3-amino-4-((5-methyl-2H-tetrazol-2-yl)methyl)azetidin-2-one (55 mg, 0.30 mmol) in DCM:DMF (2:1, 3.0 mL). After stirring at rt for 1h it was concentrated in vacuo, dissolved in EtOAc, washed with water then brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM), affording the title compound (179 mg, 99%) as a solid. LCMS: R t = 0.93 min, m / z = 594.3 (M+1) Method 2m_acidic.

[0279] Step 5: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid.

[0280] Prepared in an analogous manner to example 4, step 4 using tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (179 mg, 0.302 mmol) and SO 3 ·DMF (462 mg, 3.02 mmol) in DMF (3.0 mL) for 1 h at rt. The solution was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative). LCMS: R t = 0.80 min, m / z = 674.1 (M+1) Method 2m_acidic.

[0281] Step 6: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid. Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-methyl-2H-tetrazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid (203 mg, 0.302 mmol), DCM (3.0 mL) and TFA (1.39 mL, 18.1 mmol) for 2 h. The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (37 mg, 24%) as a white powder. LCMS: R t = 0.35 min, m / z = 518.1 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 7.03 (s, 1H), 5.37 (d, J = 5.5 Hz, 1H), 5.08-4.97 (m, 1H), 4.90-4.80 (m, 2H), 2.35 (s, 3H), 1.32 (s, 3H), 1.31 (s, 3H).Reference Example 8: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0282] Step 1: Benzyl ((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate. Prepared in an analogous manner to example 4, step 2 using benzyl ((2R,3S)-1-(2,4-dimethoxybenzyl)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate (221 mg, 0.474 mmol), K 2 S 2 O 8 (179 mg, 0.663 mmol) and K 2 HPO 4 (107 mg, 0.616 mmol) in ACN:water (2:1, 7.9 mL) at 90 °C for 1.5 h. More K 2 S 2 O 8 (38.4 mg, 0.142 mmol) and K 2 HPO 4 (21.5 mg, 0.123 mmol) were added and it was heated for an additional 30 min then cooled to rt then concentrated in vacuo. The mixture was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-10%), to afford the title compound (97 mg, 65%). LCMS: R t = 1.00 min, m / z = 317.3 (M+1) Method 2m_acidic.

[0283] Step 2: (3S,4R)-3-amino-4-((5-methy)-1H-tetrazol-1-yl)methyl)azetidin-2-one.

[0284] Prepared in an analogous manner to example 4, step 3 using benzyl ((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate (97 mg, 0.31 mmol) and Pd on C (10%, 50 mg) in EtOH:MeOH (5:1, 3.0 mL) for 3h. The crude residue was used as such in following step. LCMS: R t = 0.11 min, m / z = 183.2 (M+1) Method 2m_acidic.

[0285] Step 3: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. Prepared in an analogous manner to example 4, step 3 using (Z)-2-(((1-(fert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (130 mg, 0.302 mmol), DIPEA (158 µL, 0.906 mmol) and HATU (115 mg, 0.302 mmol) in DCM:DMF (2:1, 3.0 mL) at 0 °C followed by a solution of (3S,4R)-3-amino-4-((5-methyl-1H-tetrazol-1-yl)methyl)azetidin-2-one (55 mg, 0.30 mmol) in DCM:DMF (2:1, 3.0 mL). After stirring at rt for 1h it was concentrated in vacuo, dissolved in EtOAc, washed with water then brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM), affording the title compound (133 mg, 74%) as a solid. LCMS: R t = 0.92 min, m / z = 594.2 (M+1) Method 2m_acidic.

[0286] Step 4: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. Prepared in an analogous manner to example 4, step 4 using tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (133 mg, 0.224 mmol) and SO 3 ·DMF (343 mg, 2.24 mmol) in DMF (2.24 mL) for 1 h at rt. The solution was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative). LCMS: R t = 0.85 min, m / z = 674.2 (M+1) Method 2m_acidic.

[0287] Step 5: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0288] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-methyl-1H-tetrazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (151 mg, 0.224 mmol), DCM (2.24 mL) and TFA (1.04 mL, 13.45 mmol) for 2 h. The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (14.4 mg, 11%) as a white powder. LCMS: R t = 0.55 min, m / z = 518.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.04 (s, 1H), 5.37 (d, J = 5.5 Hz, 1H), 4.83-4.77 (m, 1H), 4.76-4.54 (m, 2H assumed; obscured by solvent), 2.48 (s, 3H), 1.35 (s, 3H), 1.33 (s, 3H).Reference Example 9: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0289] Step 1: benzyl ((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate. A 20 mL microwave vial was charged with Intermediate A (250 mg, .0522 mmol), 1,2,4-triazole (54 mg, 0.784 mmol), K 2 CO 3 (215 mg, 1.56 mmol), Nal (94 mg, 0.63 mmol) and DMF (2 mL) then heated to 70 °C with stirring. After 4 h, more 1,2,4-triazole (54 mg, 0.784 mmol), K 2 CO 3 (215 mg, 1.56 mmol) and Nal (94 mg, 0.63 mmol) were added and heating was continued. After 7 h of total heating it was cooled to rt, diluted with DCM / brine and the layers were separated. The aqueous layer was extracted with DCM and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo. Toluene was added and it was concentrated in vacuo (40 °C bath). The crude residue was purified via silica gel chromatography (Acetone-Heptane, 50%) to afford the title compound (156 mg, 66%). LCMS: Rt = 0.77 min, m / z = 452.3 (M+1) Method 2m_acidic.

[0290] Step 2: Benzyl ((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate. Prepared in an analogous manner to example 4, step 2 using benzyl ((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)carbamate (101 mg, 0.224 mmol), K 2 S 2 O 8 (85 mg, 0.313 mmol) and K 2 HPO 4 (50.7 mg, 0.291 mmol) in ACN:water (2:1, 61.5 mL) while heating for 2 h at 90 °C. More K 2 S 2 O 8 (18.1 mg, 0.067 mmol) and K 2 HPO 4 (10.1 mg, 0.058 mmol) were added and heated for another 1.5 h. More K 2 S 2 O 8 (18.1 mg, 0.067 mmol) and K 2 HPO 4 (10.1 mg, 0.058 mmol) were added and heated for another hour. It was diluted with ACN and concentrated in vacuo, removing most of the ACN. The mixture was diluted with water / DCM then added EtOAc and the layers separated. The aqueous layer was extracted with EtOAc (5x) and the combined organic layers were dried over Na 2 SO 4 . The crude residue was purified via silica gel chromatography (MeOH-DCM, 10%) to afford the title compound (38 mg, 56%). LCMS: R t = 0.50 min, m / z = 302.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, ACN-d 3 ) δ 8.17 (s, 1H), 7.92 (s, 1H), 7.49-7.31 (m, 4H), 6.82-6.74 (m, 1H), 6.67 (br s, 1H), 5.18-5.01 (m, 3H), 4.49-4.42 (m, 1H), 4.37-4.30 (m, 1H), 4.21 (q, J = 5.4 Hz, 1H).

[0291] Step 3: (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one. To a solution of benzyl ((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate (38 mg, 0.126 mmol) in MeOH (5 mL) was added Pd black (6.7 mg, 0.063 mmol) followed by formic acid (339 µL, 8.83 mmol). After 1 h of stirring, the mixture was filtered over celite, washing with MeOH, and the filtrate was concentrated in vacuo. The solution was lyophilized and the crude material was used directly in the subsequent step. LCMS: R t = 0.14 min, m / z = 168.1 (M+1) Method 2m_acidic.

[0292] Step 4: tert-butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a slurry of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (81 mg, 0.19 mmol) in DCM (800 µL) at 0 °C was added DIPEA (88 µL, 0.504 mmol) followed by HATU (72 mg, 0.190 mmol). A few drops of DMF were added to homogenize the mixture. To the resulting solution was added a solution of (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (21 mg, 0.126 mmol) in DCM (1 mL). After 1.5 h of stirring it was diluted with water / DCM and the layers separated. The aqueous layer was extracted with DCM and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford the title compound (47 mg, 65%). LCMS: R t = 0.88 min, m / z = 579.3 (M+1) Method 2m_acidic.

[0293] Step 5: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid.

[0294] tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (44 mg, 0.076 mmol) in DMF (760 µL) was treated with SO3·DMF (116 mg, 0.760 mmol). After 1 h of stirring, the solution was diluted with EtOAc / brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.81 min, m / z = 659.3 (M+1) Method 2m_acidic.

[0295] Step 6: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0296] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (50.1 mg, 0.076 mmol), DCM (760 µL) and TFA (351 µl, 4.56 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (14.8 mg, 34%) as a white powder. LCMS: R t = 0.31 min, m / z = 503.1 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.39 (d, J = 8.83 Hz, 1H), 8.52 (s, 1H), 8.02 (s, 1H), 6.74 (s, 1H), 5.28 (dd, J = 8.8, 5.4 Hz, 1H), 4.74-4.64 (m, 1H), 4.58 (d, J = 6.9 Hz, 1H), 4.32 (d, J = 5.7 Hz, 1H), 1.37 (s, 3H) 1.41 (s, 3H).Reference Example 10: 2-(((Z)-(2-(((2R,3S)-2-((3-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0297] Step 1: ((2S,3S)-3-(((benzyloxy)carbonyl)amino)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-2-yl)methyl methanesulfonate (3.10 g, 6.48 mmol), tert-butyl ((1H-1,2,4-triazol-3-yl)methyl)carbamate (1.926 g, 9.72 mmol), K 2 CO 3 (1.35 g, 9.72 mmol) and Nal (1.165 g, 7.78 mmol) were slurried in DMF (20 mL) and heated to 70 °C with stirring. After 3 h, more tert-butyl ((1H-1,2,4-triazol-3-yl)methyl)carbamate (1.926 g, 9.72 mmol), K 2 CO 3 (1.35 g, 9.72 mmol) and Nal (777 mg, 8.10 mmol) were added and it was heated an additional 4 h, whereupon it was diluted with EtOAc / water and the layers were separated. The aqueous layer was extracted with EtOAc (2x) and the combined organic layers were washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-Heptane, 0-70%) to afford the 3-substituted isomer (1.16 g, 31%) along with the 5-substituted isomer (375 mg, 10%). A-LCMS: R t = 0.87 min, m / z = 581.2 (M+1) Method 2m_acidic; B-LCMS: R t = 0.94 min, m / z = 581.2 (M+1) Method 2m_acidic; B- 1< H NMR (500 MHz, CDCl 3 ) δ 7.86 (s, 1H), 7.44-7.31 (m, 4H), 7.29 (s, 3H), 6.90 (d, J = 8.2 Hz, 1H), 6.49-6.37 (m, 2H), 5.25-5.04 (m, 3H), 4.54-4.43 (m, 2H), 4.43-4.22 (m, 3H), 4.13 (d, J = 5.4 Hz, 1H), 3.90-3.71 (m, 7H), 1.36-1.51 (m, 9H).

[0298] Step 2: Prepared in an analogous manner to Example 4, step 2 using the 3-substituted isomer from Step 1 (1.16 g, 2.00 mmol), K 2 S 2 O 8 (756 mg, 2.80 mmol) and K 2 HPO 4 (452 mg, 2.60 mmol) in ACN:water (2:1, 33.3 mL) while heating for 1.5 h at 90 °C. More K 2 S 2 O 8 (162 mg, 0.599 mmol) and K 2 HPO 4 (90 mg, 0.52 mmol) were added and heated for another 3.5 h, whereupon it was concentrated in vacuo, removing most of the ACN. The mixture was diluted with water / EtOAc and the layers were separated. The aqueous layer was extracted with EtOAc (5x) and the combined organic layers were dried over Na 2 SO 4 . The crude residue was purified via silica gel chromatography (Acetone-DCM, 0-100%) to afford the title compound (416 mg, 48%). LCMS: R t = 0.71 min, m / z = 431.3 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, ACN-d 3 ) δ 8.08 (s, 1H), 7.49-7.25 (m, 5H), 6.82-6.60 (m, 2H), 5.81-5.62 (m, 1H), 5.21-5.03 (m, 3H), 4.48-4.07 (m, 6H), 1.46-1.33 (m, 9H).

[0299] Step 3: tert-butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,4-triazol-3-yl)methyl)carbamate. Prepared according to the procedure described in Malmström et al. Bioorg. Med. Chem. Lett. 2012, 22, 5293. A solution of the product of Step 2 (416 mg, 0.966 mmol) in EtOAc:MeOH (5:1, 32.2 mL) was evacuated and backfilled with argon (2x) followed by addition of Pd on C (10%, 103 mg). The system was evacuated and backfilled with H 2 (3x). After 21 h of stirring MeOH (282 µL) was added. After an additional 4 h of stirring the mixture was filtered over celite, washing with MeOH, concentrated in vacuo, taken up on toluene and reconcentrated (3x). The crude residue was used as such in following step. LCMS: R t = 0.33 min, m / z = 297.2 (M+1) Method 2m_acidic.

[0300] Step 4: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((3-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate.

[0301] To a slurry of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (47 mg, 0.109 mmol) in DCM:DMF (12:1, 6.5 mL) at 0 °C was added DIPEA (505 µL, 2.89 mmol) followed by HATU (440 mg, 1.16 mmol). To the resulting solution was added a solution of tert-butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,4-triazol-3-yl)methyl)carbamate (286 mg, 0.964 mmol) in DCM:DMF (14:1, 7.5 mL). After 1 h of stirring it was diluted with water / EtOAc and the layers separated. The aqueous layer was extracted with EtOAc and the combined organic layers were washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM, 70%) to afford the title compound (428 mg, 63%). LCMS: R t = 0.99 min, m / z = 708.2 (M+1) Method 2m_acidic.

[0302] Step 5: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((3-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((3-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (200 mg, 0.283 mmol) in DMF (2.0 mL) was treated with SO3·DMF (433 mg, 2.83 mmol). After 20 min of stirring, the solution was diluted with EtOAc / brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: R t = 0.91 min, m / z = 788.4 (M+1) Method 2m_acidic.

[0303] Step 6: 2-(((Z)-(2-(((2R,3S)-2-((3-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0304] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((3-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (223 mg, 0.283 mmol), DCM (2.89 mL) and TFA (1.31 ml, 16.98 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (99 mg, 65%) as a white powder. LCMS: R t = 0.31 min, m / z = 532.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.45 (d, J = 8.5 Hz, 1H), 8.53 (s, 1H), 8.39 (br s, 3H), 7.32 (s, 2H), 6.74 (s, 1H), 5.23 (dd, J = 8.5, 5.7 Hz, 1H), 4.76-4.65 (m, 1H), 4.62-4.55 (m, 1H), 4.32-4.27 (m, 1H), 4.16-4.08 (m, 2H), 1.36 (s, 3H) 1.43 (s, 3H).Reference Example 11: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((3-(guanidinomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0305]

[0306] To a solution 2-(((Z)-(2-(((2R,3S)-2-((3-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (25 mg, 0.047 mmol) and pyrazole-1-carboxamidine hydrochloride (10.9 mg, 0.099 mmol) in DMF (470 µL) was added DIPEA (33 µL, 0.188 mmol). After stirring at rt for 12h the solution was concentrated in vacuo. Toluene was added and it was reconcentrated (3x). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (16 mg, 52%) as a white powder. LCMS: R t = 0.31 min, m / z = 574.3 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.45 (br s, 1H), 8.47 (s, 1H), 7.86 (br s, 1H), 7.31 (br s, 3H), 6.74 (br s, 1H), 6.55 (s, 1H), 5.22 (br s, 1H), 4.69-4.59 (m, 1H), 4.60-4.50 (m, 1H), 4.45-4.36 (m, 2H), 4.34-4.26 (m, 1H), 1.35 (s, 3H) 1.41 (s, 3H).Reference Example 12: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0307] Step 1: Prepared in an analogous manner to Example 4, step 2 using the 5-substituted isomer from Step 1 in Example 10 (361 mg, 0.622 mmol), K 2 S 2 O 8 (235 mg, 0.870 mmol) and K 2 HPO 4 (115 mg, 0.808 mmol) in ACN:water (2:1, 10.4 mL) while heating for 1.5 h at 90 °C. More K 2 S 2 O 8 (50 mg, 0.187 mmol) and K 2 HPO 4 (23 mg, 0.162 mmol) were added and heated for another 3.5 h, whereupon it was concentrated in vacuo, removing most of the ACN. The mixture was diluted with water / EtOAc and the layers were separated. The aqueous layer was extracted with EtOAc (5x) and the combined organic layers were dried over Na 2 SO 4 . The crude residue was purified via silica gel chromatography (Acetone-DCM, 0-100%) to afford the title compound (155 mg, 58%). LCMS: R t = 0.71 min, m / z = 431.2 (M+1) Method 2m_acidic.

[0308] Step 2: tert-Butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,4-triazol-5-yl)methyl)carbamate . Prepared according to Example 7, step 3. A solution of the product of Step 1 (134 mg, 0.311 mmol) in EtOAc:MeOH (5:1, 10.4 mL) was evacuated and backfilled with argon (2x) followed by addition of Pd on C (10%, 33 mg). The system was evacuated and backfilled with H 2 (3x). After 21 h of stirring MeOH (282 µL) was added. After an additional 4 h of stirring the mixture was filtered over celite, washing with MeOH, concentrated in vacuo, taken up on toluene and reconcentrated (3x). The crude residue was used as such in following step. LCMS: R t = 0.38 min, m / z = 297.2 (M+1) Method 2m_acidic.

[0309] Step 3: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1 -(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate.

[0310] To a slurry of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (160 mg, 0.373 mmol) in DCM:DMF (30:1, 3.1 mL) at 0 °C was added DIPEA (163 µL, 0.933 mmol) followed by HATU (142 mg, 0.373 mmol). To the resulting solution was added a solution of tert-butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,4-triazol-5-yl)methyl)carbamate (92 mg, 0.311 mmol) in DCM:DMF (30:1, 3.1 mL). After 1 h of stirring it was concentrated in vacuo and taken up in EtOAc / brine. The layers separated and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine (3x), dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM, 70%) to afford the title compound (128 mg, 58%). LCMS: R t = 0.97 min, m / z = 708.2 (M+1) Method 2m_acidic.

[0311] Step 4: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (128 mg, 0.181 mmol) in DMF (1.3 mL) was treated with SO3·DMF (277 mg, 1.81 mmol). After 20 min of stirring, the solution was diluted with EtOAc / brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.90 min, m / z = 788.3 (M+1) Method 2m_acidic.

[0312] Step 5: 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid .

[0313] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((5-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (143 mg, 0.181 mmol), DCM (1.81 mL) and TFA (837 µl, 10.9 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (60 mg, 62%) as a white powder. LCMS: R t = 0.28 min, m / z = 532.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.23 (d, J = 9.1 Hz, 1H), 8.40 (br s, 3H), 8.06 (s, 1H), 7.59-7.27 (m, 2H), 6.84 (s, 1H), 5.37 (dd, J = 9.0, 5.5 Hz, 1H), 4.61-4.51 (m, 1H), 4.49-4.34 (m, 3H), 4.25 (dd, J = 15.3, 5.8 Hz, 1H), 1.37 (s, 6H).Reference Example 13: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((5-(guanidinomethyl)-1H-1,2,4-triazol-1 -yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0314]

[0315] To a solution 2-(((Z)-(2-(((2R,3S)-2-((5-(aminomethyl)-1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (25 mg, 0.047 mmol) and pyrazole-1-carboxamidine hydrochloride (10.9 mg, 0.099 mmol) in DMF (470 µL) was added DIPEA (33 µL, 0.188 mmol). After stirring at rt for 12 h the solution was concentrated in vacuo. Toluene was added and it was reconcentrated (3x). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (13 mg, 42%) as a white powder. LCMS: R t = 0.29 min, m / z = 574.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 7.96-7.78 (m, 1H), 7.41-6.96 (m, 5H), 6.80-6.71 (m, 1H), 6.55 (s, 1H), 5.42-5.32 (m, 1H), 4.75-4.63 (m, 1H), 4.62-4.42 (m, 1H), 4.39-4.28 (m, 1H), 1.38 (s, 3H) 1.34 (s, 3H).Example 14: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0316] Step 1: Benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidin-3-yl)carbamate. ((2S,3S)-3-(((benzyloxy)carbonyl)amino)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-2-yl)methyl methanesulfonate (860 mg, 1.80 mmol), pyridin-2(1H)-one (855 mg, 8.99 mmol), K 2 CO 3 (1.74 g, 12.6 mmol) and Nal (746 mg, 4.49 mmol) were slurried in DMF (6.9 mL) and heated to 80 °C with stirring. After 4 h, it was cooled to rt, diluted with EtOAc and washed with brine. The organic layer was dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford title compound (304 mg, 35%).LCMS: R t = 0.79 min, m / z = 478.2 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, CDCl 3 ) δ 7.39-7.28 (m, 6H), 7.07 (d, J = 5.9 Hz, 1H), 6.93-6.85 (m, 1H), 6.55 (d, J = 9.0 Hz, 1H), 6.40 (d, J = 2.4 Hz, 1H), 6.35 (dd, J = 8.2, 2.4 Hz, 1H), 6.10-6.02 (m, 1H), 5.87 (d, J = 7.8 Hz, 1H), 5.10 (s, 2H), 4.93 (br s, 1H), 4.63 (d, J = 14.5 Hz, 1H), 4.27-4.10 (m, 1H), 3.97 (d, J = 9.0 Hz, 2H), 3.88 (d, J = 14.5 Hz, 1H), 3.78 (s, 3H), 3.76 (s, 3H).

[0317] Step 2: Benzyl ((3S,4R)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidin-3-yl)carbamate. Prepared in an analogous manner to example 4, step 2 using Benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidin-3-yl)carbamate (361 mg, 0.622 mmol), K 2 S 2 O 8 (225 mg, 0.833 mmol) and K 2 HPO 4 (135 mg, 0.773 mmol) in ACN:water (2:1, 9.9 mL) while heating for 1.5 h at 90 °C. More K 2 S 2 O 8 (45 mg, 0.17 mmol) and K 2 HPO 4 (26.9 mg, 0.155 mmol) were added and heated for another 30 min, whereupon it was concentrated, redissolved in EtOAc, washed with brine, dried over Na 2 SO 4 , and concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 0-10%) to afford the title compound (157 mg, 81%). LCMS: R t = 0.56 min, m / z = 328.2 (M+1) Method 2m_acidic.

[0318] Step 3, Compound 1: 1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)pyridin-2(1H)-one.

[0319] Step 3, Compound 2: 1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)piperidin-2-one. Prepared according to example 7, step 3. A solution of benzyl ((3S,4R)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidin-3-yl)carbamate (157 mg, 0.480 mmol) in EtOH:MeOH (5:1, 4.8 mL) was evacuated and backfilled with argon (2x) followed by addition of Pd on C (10%, 33 mg). The system was evacuated and backfilled with H 2 (3x). After 3 h of stirring the mixture was filtered over celite, washing with MeOH and concentrated in vacuo. The crude residue was used as such in following step.

[0320] Step 4, Compound 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate.

[0321] Step 4, Compound 2: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazo)-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate.

[0322] To a slurry of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (60 mg, 0.14 mmol) in DCM:DMF (1:1, 1.4 mL) at 0 °C was added DIPEA (73 µL, 0.42 mmol) followed by HATU (63.7 mg, 0.168 mmol). To the resulting solution, after 20 min, was added a mixture solution of 1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)pyridin-2(1H)-one and 1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)piperidin-2-one (90 mg, -0.46 mmol) in DCM (200 µL). After 1 h of stirring it was concentrated in vacuo and taken up in EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford title compound 1 (54 mg) and title compound 2 (30 mg). 1-LCMS: R t = 0.88 min, m / z = 605.2 (M+1) Method 2m_acidic; 2-LCMS: R t = 0.90 min, m / z = 609.2 (M+1) Method 2m_acidic.

[0323] Step 5: (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)azetidine-1-sulfonic acid. tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (30 mg, 0.049 mmol) in DMF (493 µL) was treated with SO 3 •DMF (151 mg, 0.986 mmol). After 1 h of stirring, the solution was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.78 min, m / z = 689.1 (M+1) Method 2m_acidic.

[0324] Step 6: 2-(((Z)-(1-(2-aminothiazo)-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0325] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopiperidin-1-yl)methyl)azetidine-1-sulfonic acid (34 mg, 0.049 mmol), DCM (494 µL) and TFA (228 µl, 2.96 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (5.2 mg, 17%) as a white powder. LCMS: R t = 0.63 min, m / z = 533.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.02 (s, 1H), 5.27 (d, J = 5.5 Hz, 1H), 4.59-4.48 (m, 1H), 3.61 (d, J = 4.7 Hz, 2H), 3.48-3.37 (m, 1H), 3.32 (d, J = 5.9 Hz, 1H), 2.34-2.13 (m, 2H), 1.78-1.57 (m, 4H), 1.39 (br s, 6H).Reference Example 15: 2-(((Z)-(1-(2-aminothiazo)-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0326]

[0327] Step 1: (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidine-1-sulfonicacid. tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyridin-1 (2H)-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (54 mg, 0.089 mmol) in DMF (893 µL) was treated with SO 3 •DMF (205 mg, 1.34 mmol). After 1 h of stirring, the solution was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.76 min, m / z = 685.1 (M+1) Method 2m_acidic.

[0328] Step 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid. Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxopyridin-1(2H)-yl)methyl)azetidine-1-sulfonic acid (61 mg, 0.089 mmol), DCM (891 µL) and TFA (412 µl, 5.35 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (9.6 mg, 19%) as a white powder. LCMS: R t = 0.57 min, m / z = 529.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.59 (d, J = 6.7 Hz, 1H), 7.56-7.48 (m, 1H), 7.05 (s, 1H), 6.50 (d, J = 9.0 Hz, 1H), 6.39 (t, J = 6.7 Hz, 1H), 5.30 (d, J = 5.9 Hz, 1H), 4.47 (dd, J = 14.5, 2.7 Hz, 1H), 4.07 (dd, J = 14.5, 8.6 Hz, 1H), 1.37 (s, 3H), 1.36 (s, 3H).Reference Example 16: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(5-amino-1,2,4-thiadiazol-3-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0329] Step 1: (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one. Prepared in an analogous manner to example 4, step 3 using benzyl ((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)carbamate (250 mg, 0.830 mmol) and Pd on C (10%, 125 mg) in EtOH:MeOH (4:1, 8.3 mL) for 3 h. The crude residue was used as such in following step. LCMS: R t = 0.13 min, m / z = 168.1 (M+1) Method 2m_acidic.

[0330] Step2: tert-butyl2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(5-((tert-butoxycarbonyl)amino)-1,2,4-thiadiazol-3-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a slurry of (Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(5-((tert-butoxycarbonyl)amino)-1,2,4-thiadiazol-3-yl)acetic acid (129 mg, 0.299 mmol) in DCM:DMF (1:1, 3 mL) at 0 °C was added DIPEA (157 µL, 0.897 mmol) followed by HATU (136 mg, 0.359 mmol). To the resulting solution, after 20 min, was added a solution of (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (50 mg, 0.299 mmol) in DCM. After 2 h of stirring it was concentrated in vacuo and taken up in EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford the title compound (100 mg, 58%). LCMS: R t = 0.82 min, m / z = 580.2 (M+1) Method 2m_acidic.

[0331] Step 3: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(5-((tert-butoxycarbonyl)amino)-1,2,4-thiadiazol-3-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. tert-butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(5-((tert-butoxycarbonyl)amino)-1,2,4-thiadiazol-3-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (100 mg, 0.173 mmol) in DMF (1.7 mL) was treated with SO 3 •DMF (396 mg, 2.59 mmol). After 1 h of stirring, the solution was diluted with EtOAc, washed with brine, dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.74 min, m / z = 660.2 (M+1) Method 2m_acidic.

[0332] Step 4: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(5-amino-1,2,4-thiadiazol-3-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0333] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(5-((tert-butoxycarbonyl)amino)-1,2,4-thiadiazol-3-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (114 mg, 0.173 mmol), DCM (1.7 mL) and TFA (800 µl, 10.4 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (46 mg, 46%) as a white powder. LCMS: R t = 0.42 min, m / z = 504.0 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.42 (d, J = 8.6 Hz, 1H), 8.65 (s, 1H), 8.21 (br s, 2H), 8.10 (s, 1H), 5.22 (dd, J = 8.6, 5.5 Hz, 1H), 4.67-4.58 (m, 1H), 4.56-4.47 (m, 1H), 4.28 (q, J = 5.5 Hz, 1H), 1.39 (s, 3H), 1.34 (s, 3H).Reference Example 17: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)acetic acid.

[0334] Step 1: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)acetate. To a solution of (Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (108 mg, 0.269 mmol) in DCM (2.7 mL) at 0 °C was added DIPEA (141 µL, 0.808 mmol) followed by HATU (113 mg, 0.296 mmol). To the resulting solution, after 20 min, was added a solution of (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (50 mg, 0.299 mmol) in DCM. After 1 h of stirring it was diluted with EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford the title compound (106 mg, 72%). LCMS: R t = 0.78 min, m / z = 551.2 (M+1) Method 2m_acidic.

[0335] Step2: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)acetate (100 mg, 0.182 mmol) in DMF (1.8 mL) was treated with SO 3 •DMF (278 mg, 1.82 mmol). After 1 h of stirring, the solution was diluted with EtOAc, washed with ice-cold water, brine, dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.71 min, m / z = 631.1 (M+1) Method 2m_acidic.

[0336] Step 3: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)acetic acid.

[0337] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (97 mg, 0.154 mmol), DCM (1.54 mL) and TFA (711 µl, 9.23 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (22.7 mg, 22%) as a white powder. LCMS: R t = 0.28 min, m / z = 475.0 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.50 (d, J = 9.0 Hz, 1H), 8.56 (s, 1H), 8.07 (s, 1H), 6.80 (s, 1H), 5.25 (dd, J = 9.0, 5.9 Hz, 1H), 4.69-4.49 (m, 4H), 4.36 (dt, J = 7.4, 4.9 Hz, 1H).Reference Example 18: 1-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0338] Step 1: Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate. To a solution of (Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (prepared according to Yamawaki et al. Bioorg. Med. Chem. Lett. 2007, 15, 6716-6732) (150 mg, 0.279 mmol) in DCM:DMF (1:1, 2.8 mL) at 0 °C was added DIPEA (146 µL, 0.837 mmol) followed by HATU (127 mg, 0.335 mmol). To the resulting solution, after 20 min, was added a solution of (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (51 mg, 0.31 mmol) in DCM. After 1 h of stirring it was diluted with EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM) to afford the title compound (147 mg, 77%). LCMS: R t = 0.98 min, m / z = 687.1 (M+1) Method 2m_acidic.

[0339] Step 2: (2R,3S)-2-(1H-1,2,4-triazol-1-yl)methyl-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate (147 mg, 0.214 mmol) in DMF (2.14 mL) was treated with SO 3 •DMF (328 mg, 2.14 mmol). After 1 h of stirring, the solution was diluted with EtOAc, washed with ice cold water, brine, dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.89 min, m / z = 767.0 (M+1) Method 2m_acidic.

[0340] Step 3: 1-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0341] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (164 mg, 0.214 mmol), DCM (2.14 mL) and TFA (989 µl, 12.8 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (50 mg, 41%) as a white powder. LCMS: R t = 0.29 min, m / z = 501.1 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.31 (d, J = 9.0 Hz, 1H), 8.59 (s, 1H), 8.09 (s, 1H), 6.83 (s, 1H), 5.26 (dd, J = 9.0, 5.5 Hz, 1H), 4.67 (dd, J = 14.5, 4.3 Hz, 1H), 4.49-4.39 (m, 1H), 4.33 (ddd, J = 7.4, 5.5, 4.3 Hz, 1H), 1.34-1.27 (m, 4H).Reference Example 19: 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0342] Step 1: tert-Butyl ((2-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2H-1,2,3-triazol-4-yl)methyl)carbamate. Prepared in an analogous manner to example 4, step 3 using Intermediate T (1.20 g, 2.79 mmol) and Pd on C (10%, 830 mg) in EtOAc:MeOH (5:1, 24 mL) for 19 h. The crude residue was used as such in following step. LCMS: R t = 0.41 min, m / z = 297.0 (M+1) Method 2m_acidic.

[0343] Step 2: Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate. To a solution of (Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (prepared according to Yamawaki et al. Bioorg. Med. Chem. Lett. 2007, 15, 6716-6732) (1.50 g, 2.79 mmol) in DCM (15 mL) at 0 °C was added DIPEA (1.22 mL, 6.98 mmol) and HATU (1.11 g, 2.93 mmol). After warming to rt, a solution of tert-butyl ((2-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2H-1,2,3-triazol-4-yl)methyl)carbamate (827 mg, 2.79 mmol) in DCM:DMF (1.7:1, 12.7 mL). After 1 h of stirring it was diluted with DCM and washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Heptane, 0-90%), to afford the title compound (1.92 g, 84%) as a purple oil. LCMS: R t = 1.08 min, m / z = 816.5 (M+1) Method 2m_acidic.

[0344] Step 3: (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid. Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate (1.92 g, 2.35 mmol) in DMF (20 mL) was treated with SO 3 •DMF (3.60 g, 23.5 mmol). After 30 min of stirring, the solution was diluted with EtOAc / water and the layers were separated. The aqueous was extracted with EtOAc and the combined organic layers were washed with brine, dried over Na 2 SO 4 and concd in vacuo, affording the title compound (1.98 g, 94%) as a purple foam. LCMS: Rt = 0.99 min, m / z = 896.4 (M+1) Method 2m_acidic.

[0345] Step 4: 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0346] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid (1.98 g, 2.21 mmol), DCM (18.4 mL) and TFA (10.2 mL, 133 mmol). Half of the crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (300 mg, ca 50%) as an off-white powder. LCMS: R t = 0.29 min, m / z = 530.1 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 7.69 (s, 1H), 7.04 (br s, 1H), 5.43 (d, J = 5.5 Hz, 1H), 4.93-4.78 (m, 2H), 4.74-4.67 (m, 1H), 4.22-4.12 (m, 2H), 1.36-1.20 (m, 2H), 1.20-1.00 (m, 2H).Reference Example 20: 1-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(guanidinomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0347]

[0348] To a solution of 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid (582 mg, 1.10 mmol) in DMF (12 mL) at 0 °C was added pyrazole-1-carboxamidine hydrochloride (322 mg, 2.20 mmol) and DIPEA (1.54 mL, 8.80 mmol). After 16 h of stirring at rt, the solution was diluted with toluene (60 mL), causing a dense oil to separate out. The top layer was decanted and the remaining oil was purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (240 mg, 37%) as an off-white powder. LCMS: R t = 0.31 min, m / z = 572.2 (M+H) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 7.59 (s, 1H), 6.99 (br s, 1H), 5.43 (d, J = 5.5 Hz, 1H), 4.91-4.75 (m, 2H assumed; obscured by solvent residual peak), 4.70 (dd, J = 8.2, 6.3 Hz, 1H), 4.41-4.34 (m, 2H), 1.20 (br s, 2H), 1.05 (br s, 2H). E-isomer was also obtained. LCMS: R t = 0.33 min, m / z = 572.2 (M+H) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 7.58 (s, 1H), 7.46 (br. s., 1H), 5.45 (br. s., 1H), 4.84 (s, 3H), 4.37 (s, 2H), 1.33-1.08 (m, 4H)..Example 21: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)acetic acid.

[0349] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)acetate. To a solution of (Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (100 mg, 0.249 mmol), Intermediate D (51 mg, 0.27 mmol) and HATU (123 mg, 0.324 mmol) in DMF (1.25 mL) was added DIPEA (131 µL, 0.747 mmol). After 4 h of stirring it was diluted with EtOAc, washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (0-10% MeOH-DCM) to afford the title compound (118 mg, 83%). LCMS: R t = 0.81 min, m / z = 569.1 (M+1) Method 2m_acidic.

[0350] Step 2: (3S,4R)-3-((Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)acetate (118 mg, 0.208 mmol) in DMF (2.14 mL) was treated with SO 3 •DMF (159 mg, 1.04 mmol). After 30 min of stirring, the solution was diluted with EtOAc, washed with ice-cold brine, dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.72 min, m / z = 649.1 (M+1) Method 2m_acidic.

[0351] Step 3: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)acetic acid.

[0352] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-((2-(tert-butoxy)-2-oxoethoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid (135 mg, 0.208 mmol), DCM (1.04 mL) and TFA (801 µl, 10.4 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (25 mg, 23%) as a white powder. LCMS: R t = 0.25 min, m / z = 493.0 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.41 (d, J = 9.1 Hz, 1H) 6.86 (s, 1H) 5.24 (dd, J = 9.0, 5.8 Hz, 1H) 4.62 (s, 2H) 4.20-4.11 (m, 3H) 3.72-3.63 (m, 2H) 3.40-3.31 (m, 2H assumed; obscured by water).Example 22: 1-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0353] Step 1: Benzhydryl 1-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)cyclopropanecarboxylate. To a solution of (Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (854 mg, 1.59 mmol), Intermediate D (324 mg, 1.75 mmol) and HATU (785 mg, 2.07 mmol) in DMF (7.9 mL) was added DIPEA (832 µL, 4.77 mmol). After 1 h of stirring, it was poured into water and extracted with EtOAc. Brine was added to the aqueous layer, and it was further extracted with EtOAc (3x). The combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (0-10% MeOH-DCM) to afford the title compound (1.09 g, 97%) as a beige foam. LCMS: R t = 0.97 min, m / z = 705.3 (M+1) Method 2m_acidic.

[0354] Step2: (3S,4R)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid. Benzhydryl 1-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)cyclopropanecarboxylate (1.00 g, 1.42 mmol) in DMF (7.0 mL) at 0 °C was treated with SO 3 •DMF (448 mg, 2.84 mmol). After 2 h of stirring at rt, the solution was poured into ice-cold brine and extracted with EtOAc (3x). The combined organic layers were dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: Rt = 0.90 min, m / z = 785.2 (M+1) Method 2m_acidic.

[0355] Step 3: 1-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0356] Followed the general procedure for the acid mediated deprotection using (3S,4R)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-oxo-4-((2-oxooxazolidin-3-yl)methyl)azetidine-1-sulfonic acid (1.10 g, 1.40 mmol), DCM (7.0 mL) and TFA (5.39 mL, 70.0 mmol). Additional TFA (3.24 mL, 42.0 mmol) was added after 1 h at rt and the solution was diluted with DCM and concentrated in vacuo after an additional 30 min. The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (178 mg, 23%) as a white powder. LCMS: R t = 0.30 min, m / z = 518.9 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.27 (d, J = 9.0 Hz, 1H) 6.92 (s, 1H) 5.23 (dd, J = 9.1, 5.7 Hz, 1H) 4.12-4.23 (m, 3H) 3.72-3.62 (m, 2H assumed; obscured by water) 3.61-3.52 (m, 1H assumed; obscured by water) 3.26 (dd, J = 14.5, 5.9 Hz, 1H) 1.36 (s, 4H). 1< H NMR (400 MHz, D 2 O) δ 7.23 (s, 1H), 5.48 (d, J = 5.8 Hz, 1H), 4.71-4.65 (m, 1H), 4.44 (t, J = 8.2 Hz, 2H), 3.89-3.73 (m, 3H), 3.54 (dd, J = 14.9, 4.9 Hz, 1H), 1.65-1.56 (m, 2H), 1.56-1.46 (m, 2H).Reference Example 23: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid

[0357] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((((R)-2-hydroxypropyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. A solution of Intermediate L (500 mg, 0.949 mmol) and (R)-propylene oxide (996 µl, 14.2 mmol) in DCM (1.9 ml) was stirred at rt for 16 h whereupon precipitation was observed. More (R)-propylene oxide (332 µl, 4.75 mmol) was added. After an additional 3 h, more (R)-propylene oxide (500 µl, 7.14 mmol) was added. After another 24 h of stirring it was concentrated in vacuo and the crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (185 mg, 33%) as a white powder. LCMS: R t = 0.82 min, m / z = 585.2 (M+1) Method 2m_acidic.

[0358] Step 2: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazo)-4-y))-2-(((2R,3S)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. To a solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((((R)-2-hydroxypropyl)amino)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (185 mg, 0.316 mmol) in chloroform (3.16 mL) was added CDI (257 mg, 1.58 mmol). After stirring at rt for 20 min the solution was diluted with EtOAc / water and the layers separated. The aqueous layer was extracted with EtOAc and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (Acetone-DCM, 0-100%) to afford the title compound (81 mg, 42%). LCMS: R t = 0.92 min, m / z = 611.2 (M+1) Method 2m_acidic.

[0359] Step 3: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidine-1-sulfonic acid. tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (81 mg, 0.133 mmol) in DMF (1.33 mL) was treated with SO 3 •DMF (203 mg, 1.33 mmol). After 20 min of stirring at rt, the solution was diluted with EtOAc / brine and the layers separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (assumed quantitative) as a solid. LCMS: Rt = 0.84 min, m / z = 691.0 (M+1) Method 2m_acidic.

[0360] Step 4: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid

[0361] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-(((R)-5-methyl-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidine-1-sulfonic acid (92 mg, 0.133 mmol), DCM (1.33 mL) and TFA (615 µL, 7.98 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (18.6 mg, 23%) as a white powder. LCMS: R t = 0.39 min, m / z = 535.1 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.29 (d, J = 8.8 Hz, 1H), 6.85 (s, 1H), 5.22 (dd, J = 8.8, 5.7 Hz, 1H), 4.55 (dt, J = 13.5, 6.5 Hz, 1H), 4.15 (q, J = 6.0 Hz, 1H), 3.72-3.63 (m, 2H), 3.34-3.27 (m, 2H), 1.46 (s, 3H), 1.42 (s, 3H), 1.28 (d, J = 6.3 Hz, 3H).Example 24: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-(((R)-5-(guanidinomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0362]

[0363] To a solution of 2-(((Z)-(2-(((2R,3S)-2-(((R)-5-(aminomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (30.1 mg, 0.055 mmol) and Pyrazole-1-carboxamidine hydrochloride (16.1 mg, 0.110 mmol) in DMF (548 µl) was added DIPEA (38.3 µl, 0.219 mmol). After 5 h of stirring at rt, the solution was concentrated in vacuo and purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (17.5 mg, 49%) as a white powder. LCMS: R t = 0.30 min, m / z = 592.2 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 6.97 (s, 1H), 5.31 (d, J = 5.9 Hz, 1H), 4.74 (dtd, J = 9.3, 5.9, 3.2 Hz, 1H), 4.55 (ddd, J = 9.2, 5.9, 3.1 Hz, 1H), 3.86 (t, J = 9.3 Hz, 1H), 3.66 (dd, J = 15.0, 9.5 Hz, 1H), 3.53 (dd, J = 15.5, 3.2 Hz, 1H), 3.47-3.34 (m, 3H), 1.39 (s, 3H), 1.37 (s, 3H).Example 25: 1-(((Z)-(2-(((2R,3S)-2-(((R)-5-(aminomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0364] Step 1: tert-Butyl (((R)-3-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2-oxooxazolidin-5-yl)methyl)carbamate. Prepared in an analogous manner to example 4, step 3 using Intermediate U (1.16 g, 2.28 mmol) and Pd on C (10%, 246 mg) in EtOH:MeOH (5:1, 3 mL) for 19 h. The crude residue was used as such in following step.

[0365] Step 2: Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-(((R)-5-(((tert-butoxycarbonyl)amino)methyl)-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)-thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate. To a solution of (Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (1.29 g, 2.28 mmol) and HATU (909 mg, 2.39 mmol) in DMF:DCM (3:1, 9.0 mL) at 0 °C was added DIPEA (1.0 mL, 5.72 mmol). After 15 min of stirring at 0 °C tert-butyl (((R)-3-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-2-oxooxazolidin-5-yl)methyl)carbamate (715 mg, 2.28 mmol) was added as a solution in DMF:DCM (1:1, 9 mL) followed by a DMF (1.5 mL) wash. After 1.2 h at rt it was diluted with EtOAc and washed with LiCl (5% aq). The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with LiCl (5% aq), NaHCO 3 (aq satd), brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatography (EtOAc-Heptane, 5-90%) to afford the title compound (1.357 g, 72%) as a white solid. LCMS: R t = 1.04 min, m / z = 834.4 (M+1) Method 2m_acidic.

[0366] Step 3: (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-(((R)-5-(((tert-butoxycarbonyl)amino)-methyl)-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidine-1-sulfonic acid. Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-(((R)-5-(((tert-butoxycarbonyl)amino)methyl)-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)-thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate (1.357 g, 1.627 mmol) in DMF (8.1 mL) at 0 °C was treated with SO 3 •DMF (748 mg, 4.88 mmol). After 2 h of stirring at rt, the solution was diluted with EtOAc / LiCl (5% aq) and the layers separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with LiCl (5% aq), brine, dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (assumed quantitative) as a solid. LCMS: Rt = 0.96 min, m / z = 914.4 (M+1) Method 2m_acidic.

[0367] Step 4: 1-(((Z)-(2-(((2R,3S)-2-(((R)-5-(aminomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0368] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-(((R)-5-(((tert-butoxycarbonyl)amino)-methyl)-2-oxooxazolidin-3-yl)methyl)-4-oxoazetidine-1-sulfonic acid (725 mg, 0.794 mmol), DCM (8.0 mL) and TFA (3.7 mL, 48.0 mmol). The crude residue purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (231 mg, 52%) as a white powder. LCMS: R t = 0.41 min, m / z = 548.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.18 (d, J = 8.8 Hz, 1H), 8.00 (t, J = 5.8 Hz, 3H), 6.83 (s, 1H), 5.22 (dd, J = 8.8, 5.9 Hz, 1H), 4.68 (tdd, J = 9.0, 5.8, 3.4 Hz, 1H), 4.24 (ddd, J = 9.3, 5.9, 3.6 Hz, 1H), 3.75 (t, J = 8.8 Hz, 1H assumed; obscured by water), 3.61 (dd, J = 8.7, 5.8 Hz, 1H assumed; obscured by water), 3.41 (dd, J = 14.7, 9.0 Hz, 1H), 3.30 (dd, J = 14.7, 3.7 Hz, 1H), 3.25-3.05 (m, 2H), 1.40-1.27 (m, 4H). 1H NMR (400 MHz, D 2 O) δ 7.18 (d, J = 2.4 Hz, 1H), 5.45 (d, J = 5.8 Hz, 1H), 5.02-4.93 (m, 1H), 4.70 (ddd, J = 9.2, 5.8, 3.7 Hz, 1H), 4.04 (t, J = 9.2 Hz, 1H), 3.78 (dd, J = 15.0, 9.0 Hz, 1H), 3.60-3.56 (m, 1H), 3.54 (dd, J = 11.3, 3.6 Hz, 1H), 3.40 (s, 1H), 3.38 (d, J = 2.0 Hz, 1H), 1.57-1.49 (m, 2H), 1.49-1.40 (m, 2H).Example 26: 1-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-(((R)-5-(guanidinomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0369]

[0370] To a solution of 1-(((Z)-(2-(((2R,3S)-2-(((R)-5-(aminomethyl)-2-oxooxazolidin-3-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropane-carboxylic acid (0.795 mmol) and Pyrazole-1-carboxamidine hydrochloride (234.8 mg, 1.602 mmol) in DMF (7.0 mL) was added DIPEA (1.20 mL, 8.06 mmol). After 19 h of stirring at rt, the solution was concd in vacuo and purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (177 mg, 37%) as a white powder. LCMS: R t = 0.47 min, m / z = 590.1 (M+H) Method 2m_acidic_polar; ; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.15 (d, J = 8.9 Hz, 1H), 7.62 (br s, 1H), 7.24 (s, 3H), 6.81 (s, 1H), 5.23 (dd, J = 8.9, 5.9 Hz, 1H), 4.60-4.51 (m, 1H), 4.23 (ddd, J = 9.0, 5.8, 3.7 Hz, 1H), 3.70 (t, J = 8.8 Hz, 1H), 3.52 (dd, J = 8.8, 5.4 Hz, 1H), 3.49-3.44 (m, 1H), 3.43-3.34 (m, 3H), 1.38-1.24 (m, 4H).Reference Example 27: 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylic acid.

[0371] Step 1: tert-Butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)carbamate. To a suspension of palladium on carbon (823 mg, 0.774 mmol) in EtOAc / MeOH (5:1, 16.8 mL) was added Intermediate S (1.11 g, 2.58 mmol) in one portion. The system was evacuated and backfilled with H 2 (3x). After stirring for 19 h the mixture was diluted with EtOAc, filtered through celite, washing with MeOH-EtOAc (20%, 100 mL x 3) and concentrated in vacuo, affording crude title compound (730 mg) as an off-white powder. LCMS: R t = 0.37 min, m / z = 297.0 (M+1) Method 2m_acidic.

[0372] Step 2: Benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate. To a slurry of (Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (1.32 g, 2.46 mmol) in DCM (12 mL) at 0 °C was added DIPEA (1.08 mL, 6.16 mmol) followed by HATU (0.984 g, 2.59 mmol). The reaction mixture was warmed to room temperature and tert-butyl ((1-(((2R,3S)-3-amino-4-oxoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)carbamate (0.73 g, 2.5 mmol) was added as a solution in DCM:DMF(1.7:1, 9.6 mL). After stirring for 1.3 h, a color change from yellow to dark purple was observed, whereupon it was diluted with DCM, washed with water, brine, dried over sodium sulfate and concentrated in vacuo. The crude residue was purified by silica gel chromatography (EtOAc-Heptane, 0-90%), affording the title compound (1.62 g, 81%) as a purple foam. LCMS: R t = 1.05 min, m / z = 816.5 (M+1) Method 2m_acidic.

[0373] Step 3: (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. To a solution of benzhydryl 1-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclopropanecarboxylate (1.58 g, 1.94 mmol) in DMF (15 mL) was added SO 3 •DMF complex (2.97 g, 19.4 mmol). After 45 min of stirring it was diluted with EtOAc (120 mL), brine (80 mL), water (40 mL) and the layers were separated. The aqueous layer was extracted with EtOAc (2 x 20 mL) and the combined organic layers were dried over Na 2 SO 4 and concentrated in vacuo to afford the title compound (assumed quantitative) as a purple foam. LCMS: R t = 0.96 min, m / z = 896.4 (M+1) Method 2m_acidic.

[0374] Step 4: 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid. Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-((1-((benzhydryloxy)carbonyl)cyclopropoxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (1.74 g, 1.94 mmol), DCM (19.4 mL) and TFA (8.95 mL, 116 mmol). After 3 h at rt, it was cooled to 0 °C and more TFA (200 µL, 2.6 mmol) was added whereupon it was allowed to warm to rt. After another 1 h at rt, it was cooled to 0 °C and more TFA (200 µL, 2.6 mmol) was added, again allowing to warm to rt. After an additional 1 h at rt it was diluted with DCM and concentrated in vacuo. Half of the crude residue was purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (140 mg, ca 23%) as a white powder. LCMS: R t = 0.27 min, m / z = 530.1 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 8.07 (s, 1H), 7.08-6.99 (m, 1H) 5.42-5.31 (m, 1H), 4.88-4.74 (m, 2H assumed; partially obscured by solvent residual peak), 4.74-4.68 (m, 1H), 4.20 (s, 2H), 1.36-1.23 (m, 2H),1.23-1.07 (m, 2H).Reference Example 28: 1-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(guanidinomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-cyclopropanecarboxylic acid.

[0375]

[0376] To a solution of 1-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2 oxoethylidene)amino)oxy)cyclopropane-carboxylic acid (559 mg, 1.06 mmol) and Pyrazole-1-carboxamidine hydrochloride (310 mg, 2.12 mmol) in DMF (12 mL) was added DIPEA (1.48 mL, 8.45 mmol). After 16 h of stirring at rt, the solution was diluted with toluene (20 mL), causing a dense oil to separate out. The top layer was decanted and the remaining oil was purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (240 mg, 39%) as a white powder. LCMS: R t = 0.28 min, m / z = 572.0 (M+H) Method 2m_acidic; 1< H NMR (400 MHz, D 2 O) δ 8.09 (s, 1H), 7.18 (s, 1H), 5.52 (d, J = 5.4 Hz, 1H), 4.97 (dd, J = 14.1, 5.5 Hz, 1H), 4.91 (q, J = 5.5 Hz, 1H), 4.84-4.76 (m, 1H assumed; partially obscured by solvent residual peak), 4.55 (s, 2H), 1.49-1.36 (m, 2H), 1.34-1.23 (m, 2H).. E-isomer was also obtained. LCMS: R t = 0.32 min, m / z = 572.0 (M+H) Method 2m_acidic. 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.37 (d, J = 9.6 Hz, 1H), 8.11 (s, 1H), 7.41 (s, 1H), 7.13 (s, 2H), 6.50 (s, 1H), 5.18 (dd, J = 9.6, 5.3 Hz, 1H), 4.97 (d, J = 13.5 Hz, 1H), 4.76-4.58 (m, 1H), 4.52 (dd, J = 16.11, 7.70 Hz, 1H), 4.26-4.05 (m, 2H), 1.86-2.08 (m, 1 H), 1.34-1.07 (m, 6 H).Reference Example 29: (S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)propanoic acid.

[0377] Step 1: (R)-tert-Butyl 2-chloropropanoate. Prepared according to Wright et al. Tetrahedron Lett. 1997, 38, 7345. A 500 mL glass bomb was charged with magnesium sulfate (4.21 g, 35.0 mmol) and DCM (43.8 mL). To this suspension was added sulfuric acid (486 µL, 8.75 mmol), drop-wise with vigorous stirring. After 15 min of stirring, (R)-2-chloropropanoic acid (950 mg, 8.75 mmol) was added followed by tert-butanol (4.20 ml, 43.8 mmol). The bomb was sealed and stirred at rt for 19 h, whereupon sodium bicarbonate (aq satd, 100 mL) was carefully added, at which point all solids had dissolved. The layers were separated and the aqueous layer was extracted with DCM (2x). The combined organics layers were washed with brine, dried over Na 2 SO 4 and concentrated in vacuo (20 °C bath, 50 mBar) to afford the title compound (1.36 g, 94%) as a light pink oil. 1< H NMR (500 MHz, CDCl 3 ) δ 4.29 (q, J = 6.9 Hz, 1H) 1.65 (d, J = 6.9 Hz, 3H) 1.49 (s, 9H).

[0378] Step2: (S)-tert-butyl 2-((1,3-dioxoisoindolin-2-yl)oxy)propanoate. Prepared according to Yamawaki et al. Bioorg. Med. Chem. 2007, 15, 6716. To a slurry of N-hydroxyphthalimide (517 mg, 3.17 mmol) and potassium carbonate (657 mg, 4.76 mmol) in DMF (4.5 mL) was added (R)-tert-butyl 2-chloropropanoate (522 mg, 3.17 mmol). Additional DMF (4.5 mL) was added after the slurry became viscous. After stirring for 5 d it was diluted with EtOAc and poured into LiCl soln (5% aq, 90 mL). The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with LiCl (5% aq), brine, dried over Na 2 SO 4 and concd in vacuo. The crude residue was purified by silica gel chromatogrphy (EtOAc-Heptane, 0-50%), affording the title compound (348 mg, 38%) as a white solid. LCMS: R t = 0.89 min, m / z = 314.0 (M+23) Method 2m_acidic; 1< H NMR (400 MHz, CDCl 3 ) δ 7.87-7.81 (m, 2H), 7.75 (dd, J = 5.5, 3.1 Hz, 2H), 4.79 (q, J = 6.8 Hz, 1H), 1.61 (s, 3H), 1.46 (s, 9H).

[0379] Step 3: (S)-tert-butyl 2-(aminooxy)propanoate. To a solution of (S)-tert-butyl 2-((1,3-dioxoisoindolin-2-yl)oxy)propanoate (73.3 mg, 0.252 mmol) in DCM (Volume: 500 µL) at 0 °C was added methyl hydrazine (13.5 µL, 0.252 mmol). After stirring for 3 h at 0 °C, the solids were filtered off and the filtrate was concentrated in vacuo, affording the title compound (assumed quantitative) as a clear oil.

[0380] Step 4: (S)-tert-butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-propanoate. To a soln of Intermediate E (62.2 mg, 0.148 mmol) in MeOH (1 mL) at 0 °C was added a soln of (S)-tert-butyl 2-(aminooxy)propanoate (24 mg, 0.15 mmol) in DCM (300 µL). After stirring for 6 d acetic acid (8.5 µl, 0.15 mmol) was added. After 4 d more acetic acid (8.5 µl, 0.15 mmol) was added. After an additional 24 h, it was partially concentrated in vacuo then diluted with EtOAc / water. The layers were separated and the organic layer was washed with brine, dried over Na 2 SO 4 and concd in vacuo. The crude residue was purified by silica gel chromatography (MeOH-DCM, 0-10%), affording the title compound (20.2 mg, 24%) as a white solid. LCMS: R t = 0.81 min, m / z = 565.1 (M+1) Method 2m_acidic.

[0381] Step 5: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((S)-1-(tert-butoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. To a soln of (S)-tert-butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)propanoate (20.2 mg, 0.036 mmol) in DMF (400 µl) was added SO 3 •DMF (54.8 mg, 0.358 mmol). After 2.5 h of stirring it was diluted with EtOAc / LiCl (5% aq) and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with LiCl (5% aq), brine, dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: R t = 0.74 min, m / z = 645.3 (M+1) Method 2m_acidic.

[0382] Step 6: (S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)propanoic acid. Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((((S)-1-(tert-butoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (23 mg, 0.036 mmol), DCM (357 µL) and TFA (165 µL, 2.14 mmol). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (7.9 mg, 36%) as a white powder. LCMS: R t = 0.40 min, m / z = 489.0 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 8.69 (s, 1H), 8.18 (s, 1H), 7.20 (s, 1H), 5.54 (d, J = 5.7 Hz, 1H), 4.96-4.67 (m, 4H assumed; partially obscured by solvent residual peak), 1.44 (d, J = 7.0 Hz, 3H).Reference Example 30: (R)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)propanoic acid.

[0383] Step 1: (S)-tert-Butyl 2-chloropropanoate. Prepared according to Wright et al. Tetrahedron Lett. 1997, 38, 7345. A 500 mL glass bomb was charged with magnesium sulfate (21.7 g, 181 mmol) and DCM (182 mL). To this suspension was added sulfuric acid (2.5 mL, 45 mmol), drop-wise with vigorus stirring. After 15 min of stirring, (S)-2-chloropropanoic acid (5.0 g, 45 mmol) was added followed by tert-butanol (21.6 ml, 226 mmol). The bomb was sealed and stirred at rt for 19 h, whereupon it was cooled to 0 °C and sodium bicarbonate (aq satd, 350 mL) was carefully added, at which point all solids had dissolved. The layers were separated and the aqueous layer was extracted with DCM (2x). The combined organics layers were washed with brine, dried over Na 2 SO 4 and concentrated in vacuo (20 °C bath, 50 mBar) to afford the title compound (7.64 g, 96%) as a light yellow oil (93% purity). 1< H NMR data was an identical match to the previously prepared enantiomer.

[0384] Step2: (R)-tert-butyl 2-((1,3-dioxoisoindolin-2-yl)oxy)propanoate. To a slurry of N-hydroxyphthalimide (3.71 g, 22.1 mmol) and potassium carbonate (4.58 g, 33.1 mmol) in DMF (55 mL) was added (S)-tert-butyl 2-chloropropanoate (4.30 g, 24.3 mmol). After 72 h of stirring, the slurry was heated to 40 °C for an additional 16 h, at which point it was diluted with EtOAc / LiCl (5% aq) and the layers were separated. The aqueous layer was extracted with EtOAc (2x) and the combined organic layers were washed with LiCl (5% aq), brine, dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (5.45 g, 85%) as an off-white solid. LCMS: R t = 0.88 min, m / z = 313.9 (M+23) Method 2m_acidic.

[0385] Step 3: (R)-tert-butyl 2-(aminooxy)propanoate. To a solution of (R)-tert-butyl 2-((1,3-dioxoisoindolin-2-yl)oxy)propanoate (69.6 mg, 0.239 mmol) in DCM (478 µL) at 0 °C was added methyl hydrazine (12.8 µl, 0.239 mmol). After stirring for 3 h at 0 °C, the solids were filtered off and the filtrate was concentrated in vacuo, affording the title compound (assumed quantitative) as a clear oil.

[0386] Step 4: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((((R)-1-(tert-butoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. To a soln of Intermediate F (110 mg, 0.219 mmol) in MeOH (2 mL) at 0 °C was added a soln of (R)-tert-butyl 2-(aminooxy)propanoate (38.5 mg, 0.239 mmol) in DCM:MeOH (2:1, 600 µL) followed by a DCM (400 µL) wash. After stirring for 16 h it was partially concentrated in vacuo then diluted with EtOAc / water and the layers were separated. The aqueous layer was extracted with EtOAc (2x) and the combined organic layers were dried over Na 2 SO 4 and concd in vacuo, affording the title compound (assumed quantitative) as a white solid. LCMS: R t = 0.74 min, m / z = 645.3 (M+1) Method 2m_acidic.

[0387] Step 5: (R)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)propanoic acid.

[0388] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((((R)-1-(tert-butoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (141 mg, 0.219 mmol), DCM (2.19 mL) and TFA (1.0 mL, 13 mmol). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 60 mL / min), affording the title compound (35.5 mg, 29%) as a white powder. LCMS: R t = 0.42 min, m / z = 489.0 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 8.58 (s, 1H), 8.06 (s, 1H), 7.06 (s, 1H), 5.41 (d, J = 5.6 Hz, 1H), 4.81-4.52 (m, 4H assumed; partly obscured by solvent peak), 1.29 (d, J = 7.0 Hz, 3H).Reference Example 31: (S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-3-(4-(N-(piperidin-4-yl)carbamimidoyl)-phenoxy)propanoic acid.

[0389] Step 1: tert-Butyl 4-(4-((S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-3-(benzhydryloxy)-3-oxopropoxy)benzimidamido)piperidine-1-carboxylate. To a solution of (S,Z)-2-(((1-(benzhydryloxy)-3-(4-(N-(1-(tert-butoxycarbonyl)piperidin-4-yl)carbamimidoyl)phenoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetic acid (Prepared according to WO2013110643, 72 mg, 0.085 mmol), (3S,4R)-4-((1H-1,2,4-triazol-1-yl)methyl)-3-aminoazetidin-2-one (15.7 mg, 0.094 mmol) and HATU (42.2 mg, 0.111 mmol) in DMF (854 µL) was added DIPEA (44.8 µl, 0.256 mmol). After stirring at for 3 h it was diluted with EtOAc, washed with water, NaHCO 3 (aq satd), brine, dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (82 mg, 87%) as an olive film. LCMS: R t = 0.97 min, m / z = 992.5 (M+1) Method 2m_acidic.

[0390] Step 2: (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((((S)-1-(benzhydryloxy)-3-(4-(N-(1-(tert-butoxycarbonyl)piperidin-4-yl)carbamimidoyl)phenoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid. tert-Butyl 4-(4-((S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-3-(benzhydryloxy)-3-oxopropoxy)benzimidamido)piperidine-1-carboxylate (99 mg, 0.10 mmol) in DMF (500 µL) was treated with SO 3 •DMF (45.9 mg, 0.299 mmol). After stirring for 40 min more SO 3 •DMF (45.9 mg, 0.299 mmol) was added. After 1.3 h more SO 3 •DMF (45.9 mg, 0.299 mmol) was added. After stirring for an additional 30 min the solution was poured into ice-cold brine and extracted with EtOAc. The layers were separated and the organic layer was dried over Na 2 SO 4 and concentrated in vacuo, affording the title compound (assumed quantitative) as an off white solid. LCMS: R t = 0.97 min, m / z = 1073.1 (M+1) Method 2m_acidic.

[0391] Step 3: (S)-2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-3-(4-(N-(piperidin-4-yl)carbamimidoyl)-phenoxy)propanoic acid.

[0392] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-3-((Z)-2-((((S)-1-(benzhydryloxy)-3-(4-(N-(1-(tert-butoxycarbonyl)piperidin-4-yl)carbamimidoyl)phenoxy)-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (0.085 mmol), DCM (850 µL) and TFA (327 µL, 4.25 mmol). The crude residue was purified by reverse phase prep HPLC (XSelect CSH, 19 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 24 mL / min), affording the title compound (12 mg, 17%) as a white powder. LCMS: R t = 0.41 min, m / z = 706.2 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.55 (d, J = 7.4 Hz, 1H) 9.40 (br s, 1H) 9.01 (br s, 1H) 8.53-8.71 (m, 1H) 8.41 (s, 1H) 7.92 (s, 1H) 7.67 (d, J = 9.0 Hz, 2H) 7.21 (br s, 2H) 7.03 (d, J = 7.8 Hz, 1H) 6.76 (s, 1H) 5.17-5.24 (m, 1H) 4.94 (d, J = 3.9 Hz, 1H) 4.46-4.53 (m, 2H) 4.37-4.45 (m, 1H) 4.25-4.32 (m, 1H) 3.88 (br s, 1H) 3.39 (br s, 4H) 2.92 (t, J = 11.5 Hz, 2H) 2.05-2.14 (m, 2H) 1.79 (d, J = 11.0 Hz, 2H).Reference Example 32: 1-(((Z)-(2-(((2R,3S)-2-((1H-1,2,4-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)cyclobutanecarboxylic acid.

[0393]

[0394] LCMS: R t = 0.58 min, m / z = 515.0 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 8.75 (s, 1H), 8.22 (s, 1H), 7.23 (s, 1H), 5.56 (d, J = 5.6 Hz, 1H), 4.95-4.85 (m, 2H), 4.86-4.82 (m, 1H assumed; partially obscured by solvent residual peak), 4.78-4.70 (m, 1H assumed; partially obscured by solvent residual peak), 2.61-2.46 (m, 2H), 2.38-2.27 (m, 2H), 2.00-1.89 (m, 2H).Reference Example 33: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(cyanomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0395]

[0396] LCMS: R t = 0.57 min, m / z = 542.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.19 (d, J = 9.0 Hz, 1H), 7.71 (s, 1H), 6.65 (s, 1H), 5.43-5.23 (m, 1H), 4.93-4.84 (m, 1H), 4.76-4.67 (m, 1H), 4.47 (ddd, J = 8.71, 5.4, 3.5 Hz, 1H), 4.07 (d, J = 1.6 Hz, 2H), 1.35 (s, 6H).Reference Example 34: 2-(((Z)-(2-(((2R,3S)-2-((3-amino-1H-pyrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0397]

[0398] LCMS: R t = 0.50 min, m / z = 517.3 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.54 (d, J = 2.5 Hz, 1H), 6.97 (s, 1H), 6.00 (d, J = 2.4 Hz, 1H), 5.40 (d, J = 5.8 Hz, 1H), 4.69 (q, J = 5.5 Hz, 1H), 4.43 (d, J = 5.4 Hz, 2H), 1.31 (d, J = 1.8 Hz, 6H).Reference Example 35: 2-(((Z)-(2-(((2R,3S)-2-((4-amino-1H-pyrazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0399]

[0400] LCMS: R t = 0.39 min, m / z = 517.1 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.86 (s, 1H), 7.56 (s, 1H), 6.90 (s, 1H), 5.35 (d, J = 5.9 Hz, 1H), 4.72-4.67 (m, 1H), 4.54-4.49 (m, 2H), 1.28 (s, 3H), 1.27 (s, 3H).Reference Example 36: (2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-((4-((1-methylpyrrolidin-1-ium-1-yl)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonate.

[0401]

[0402] LCMS: R t = 0.55 min, m / z = 600.3 (M+) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 12.50 (s, 1H), 9.34 (s, 1H), 7.94 (s, 1H), 7.27 (s, 2H), 6.72 (s, 1H), 5.33 (dd, J = 8.6, 5.6 Hz, 1H), 4.82 (dd, J = 15.1, 9.2 Hz, 1H), 4.69-4.53 (m, 4H), 3.60-3.50 (m, 2H), 3.46-3.33 (m, 2H), 2.95 (s, 3H), 2.14-2.00 (m, 4H), 1.35 (s, 3H), 1.29 (s, 3H).Reference Example 37: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-((carbamoyloxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0403]

[0404] LCMS: R t = 0.53 min, m / z = 576.0 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.23 (d, J = 9.3 Hz, 1H), 7.70 (s, 1H), 6.74 (s, 1H), 6.59 (br s, 2H), 5.31 (dd, J = 9.2, 5.4 Hz, 1H), 4.94 (s, 2H), 4.91 (dd, J = 14.3, 3.2 Hz, 1H), 4.72 (dd, J = 14.2, 9.0 Hz, 1H), 4.42 (ddd, J = 8.8, 5.5, 3.1 Hz, 1H), 1.38 (s, 3H), 1.37 (s, 3H).Reference Example 38: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-1-sulfo-4-((4-((sulfooxy)methyl)-2H-1,2,3-triazol-2-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid.

[0405]

[0406] LCMS: R t = 0.43 min, m / z = 612.9 (M+1) Method 2m_acidic_polar; 1< H NMR (400 MHz, D 2 O) δ 7.71 (s, 1H), 6.96-7.11 (m, 1H), 5.40 (d, J = 5.5 Hz, 1H), 4.98 (s, 2H), 4.93-4.65 (m 3H assumed; partially obscured by solvent residual peak), 1.34 (s, 6H).Reference Example 39: 2-(((Z)-(2-(((2R,3S)-2-((2-amino-4,5-dihydro-1H-imidazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0407]

[0408] LCMS: R t = 0.30 min, m / z = 520.1 (M+1) Method 2m_acidic; 1< H NMR (400 MHz, DMSO-d 6 ) δ 12.63 (br s, 1H) 9.12 (d, J = 8.6 Hz, 1H) 7.74 (d, J = 15.3 Hz, 3H) 7.31-7.49 (m, 2H) 6.77 (s, 1H) 5.22 (dd, J = 8.5, 5.8 Hz, 1H) 4.24 (dt, J = 7.1, 5.3 Hz, 1H) 3.76-3.85 (m, 1H) 3.59-3.73 (m, 2H) 3.43-3.55 (m, 3H) 1.43 (s, 3H) 1.41, (s, 3H).Reference Example 40: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-(((E)-2-(cyanoimino)imidazolidin-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0409]

[0410] LCMS: R t = 0.33 min, m / z = 544.0 (M+1) Method 2m_acidic; 1< H NMR (500 MHz, DMSO-d 6 ) δ 9.29 (d, J = 9.1 Hz, 1H) 7.74 (br s, 1H) 6.85 (s, 1H) 5.20 (dd, J = 8.8, 5.7 Hz, 1H) 4.10-4.17 (m, 1H) 3.72-3.81 (m, 1H) 3.62 (dd, J = 14.7, 6.8 Hz, 1H) 3.48-3.56 (m, 1H) 3.31-3.42 (m, 3H) 1.43 (s, 3H) 1.41, (s, 3H).Reference Example 41: 2-(((Z)-(2-(((2R,3S)-2-((4-(2-aminoethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid

[0411]

[0412] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(2-((tert-butoxycarbonyl)amino)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. To a mixture of Intermediate K (100 mg, 0.158 mmol) and tert-butyl but-3-yn-1-ylcarbamate (54 mg, 0.32 mmol) in DMSO: water: tert-butanol (1: 1: 1, 3 mL) was added CuSO 4 (13 mg, 0.079 mmol) and sodium L-ascorbate (32 mg, 0.16 mmol). After overnight stirring the mixture was diluted with EtOAc and water. The layers were separated and aqueous layer was extracted with EtOAc (3x). The combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was washed with diethyl ether / pentane, affording the title compound (80 mg, 63%) as a white solid. LCMS: m / z = 799.8 (M-1).

[0413] Step2: 2-(((Z)-(2-(((2R,3S)-2-((4-(2-aminoethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid. To a solution of (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(2-((tert-butoxycarbonyl)amino)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (110 mg, 0.137 mmol) in DCM (1.4 mL) at 0 °C added TFA: DCM (1:1, 4.2 mL) followed by triethylsilane (65 µL, 0.411 mmol). The reaction mixture was stirred at 0 °C for 30 min and slowly warmed to room temperature. After 2 h at rt it was concentrated in vacuo and triturated with MTBE:Heptane (1:2) whereupon a solid was observed. The crude solid was purified by reverse phase prep HPLC (C18 column, acetonitrile: water solvent system with 0.1% formic acid modifier) to afford the title compound (5 mg, 7%); LCMS: m / z = 543.9 (M-1); 1< H NMR (400 MHz, MeOH-d 4 ) δ 8.06 (s, 1H), 6.95 (s, 1H), 5.44 (d, J = 5.8 Hz, 1H), 4.66 (q, J = 6.0 Hz, 1H), 4.95-4.83 (m, 2H assumed; obscured by water), 3.29-3.24 (m, 2H), 3.07 (t, J = 6.5 Hz, 2H), 1.54 (s, 3H), 1.52 (s, 3H).Reference Example 42: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((4-(2-(piperazin-1-yl)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid

[0414] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(2-(4-(tert-butoxycarbonyl)piperazin-1-yl)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. To a solution of Intermediate K (90 mg, 0.142 mmol) and tert-butyl 4-(but-3-yn-1-yl)piperazine-1-carboxylate (34 mg, 0.14 mmol) in a mixture of DMSO:water:tert-butanol (1:1:1, 2.16 mL) was added CuSO 4 (2.5 mg, 0.016 mmol) and sodium L-ascorbate (5 mg, 0.15 mmol). After overnight stirring the mixture was diluted with EtOAc and water. The layers were separated and aqueous layer was extracted with EtOAc (3x). The combined organic layers were washed with water, brine, dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was washed with diethyl ether / pentane, affording the title compound (120 mg, crude); LCMS: m / z = 871.4 (M+1).

[0415] Step 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((4-(2-(piperazin-1-yl)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-1-sulfoazetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoic acid

[0416] To a solution of (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(2-(4-(tert-butoxycarbonyl)piperazin-1-yl)ethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (120 mg, 0.138 mmol) in DCM (1.4 mL) at 0 °C added TFA: DCM (1:1, 4.2 mL) followed by triethylsilane (65 µL, 0.411 mmol). The reaction mixture was stirred at 0 °C for 30 min and slowly warmed to room temperature. After 2 h at rt it was concentrated in vacuo and triturated with MTBE: Heptane (1:2) whereupon a solid was observed. The crude solid was purified by reverse phase prep HPLC (C18 column, acetonitrile: water solvent system with 0.1% formic acid modifier) to afford the title compound (9.3 mg, 11%); LCMS: m / z = 612.8 (M-1); 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.67 (s, 1H), 7.99 (s, 1H), 7.30 (s, 2H), 6.66 (s, 1H), 5.27 (dd, J = 8.8, 5.5 Hz, 1H), 4.82 (dd, J = 14.7, 4.0 Hz, 1H), 4.68 (dd, J = 14.7, 6.6 Hz, 1H), 4.24 (td, J = 5.9, 4.2 Hz, 1H), 3.10 (t, J = 5.2 Hz, 4H), 2.76 (t, J = 7.0 Hz, 2H), 2.64-2.54 (m, 6H), 1.37 (s, 3H), 1.30 (s, 3H).Reference Example 43: (3S,4R)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-oxo-4-((4-((2-(trimethylammonio)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)azetidine-1-sulfonate.

[0417] Step 1: 2-(((1-(((2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxo-1-sulfoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)amino)-N,N,N-trimethy)-2-oxoethanamonium bromide. To a solution of Intermediate K (100 mg, 0.158 mmol) and N,N,N-trimethyl-2-oxo-2-(prop-2-yn-1-ylamino)ethanamonium bromide (50 mg, 0.212 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 3 mL) was added CuSO 4 (2.5 mg, 0.016 mmol) and sodium L-ascorbate (5 mg, 0.15 mmol). The mixture was stirred overnight and quenched with ice-cold water, whereupon the resulting solids were filtered and dried in vacuo to afford crude title compound (50 mg, 40%); LCMS: m / z = 784.85 (M-1).

[0418] Step 2: (3S,4R)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-oxo-4-((4-((2-(trimethylammonio)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)azetidine-1-sulfonate.

[0419] To a slurry of 2-(((1-(((2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxo-1-sulfoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)amino)-N,N,N-trimethyl-2-oxoethanaminium bromide (50 mg, 0.0635 mmol) In DCM (640 µL) at 0 °C was added TFA: DCM (1:1, 1.92 mL) followed by triethylsilane (31 µL, 0.19 mmol). The reaction mixture was stirred at 0 °C for 30 min and slowly warmed to room temperature. After 2 h at rt, it was concentrated in vacuo and triturated with MTBE:Heptane (1:2) whereupon a solid was observed. The crude solid was purified by reverse phase prep HPLC (C18 column, acetonitrile: water solvent system with 0.1% formic acid modifier) to afford the title compound (11 mg, 27%). LCMS: m / z = 630.9 (M-1); 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.40 (d, J = 8.6 Hz, 1H), 9.06 (t, J = 5.6 Hz, 1H), 8.06 (s, 1H), 7.32 (s, 2H), 6.71 (s, 1H), 5.28 (dd, J = 8.6, 5.5 Hz, 1H), 4.89-4.64 (m, 2H), 4.38 (t, J = 5.1 Hz, 2H), 4.22 (q, J = 5.3 Hz, 1H), 4.08 (s, 2H), 3.22 (s, 9H), 1.33 (s,3H), 1.26 (s, 3H).Reference Example 44: 2-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0420] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid . To a solution of Intermediate K (100 mg, 0.158 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 1.5 mL) at 0 °C was added N-Boc-propargyl amine (50 mg, 0.321 mmol), CuSO 4 (13 mg, 0.079 mmol) and sodium L-ascorbate (48 mg, 0.237 mmol). The resulting mixture was gradually brought to rt and stirred for 3 h. It was then diluted with EtOAc and brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with brine, dried over Na 2 SO 4 then concentrated in vacuo to afford crude title compound (120 mg, 96%); LCMS: m / z = 787.95 (M+1).

[0421] Step 2: 2-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0422] To a slurry of (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-1 H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (120 mg, 0.15 mmol) In DCM (1.5 mL) at 0 °C was added TFA: DCM (1:1, 4.5 mL) followed by triethylsilane (72 µL, 0.45 mmol). The reaction mixture was stirred at 0 °C for 30 min and slowly warmed to room temperature. After 2 h at rt it was concentrated in vacuo and triturated with MTBE: Heptane (1:2) whereupon a solid was observed. The crude solid was purified by reverse phase prep HPLC (C18 column, acetonitrile: water solvent system with 0.1% formic acid modifier) to afford the title compound (11.3 mg, 14%). LCMS: m / z = 528.9 (M-1); 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.47 (d, J = 8.5 Hz, 1H), 8.25 (s, 1H), 7.30 (s, 2H), 6.75 (s, 1H), 5.27 (dd, J = 8.6, 5.6 Hz, 1H), 4.82 (qd, J = 14.9, 5.0 Hz, 2H), 4.23 (q, J = 5.1 Hz, 1H), 4.09 (s,2H), 1.37 (s, 3H), 1.32 (s, 3H).Reference Example 45: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(guanidinomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0423]

[0424] Step 1: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-((2,3-bis(tert-butoxycarbonyl)guanidino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid. To a solution of 2-(((Z)-(2-(((2R,3S)-2-((4-(ammoniomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid trifluoroacetate (150 mg, 0.122 mmol) In DCM (10 mL) was added DIPEA (100 µL, 0.610 mmol) followed N,N-di-Boc-1H-pyrazole-1-carboxamidine (42 mg, 0.134 mmol). The solution was stirred at RT overnight whereupon it was concentrated in vacuo, water was added and it was lyophilized for 72 h to afford crude title compound (210 mg, assumed quantitative conversion). LCMS: m / z = 772.1 (M-1).

[0425] Step 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(guanidinomethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0426] General Procedure for Acid Mediated Deprotection. To a solution of 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-((2,3-bis(tert-butoxycarbonyl)guanidino)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (0.15 mmol, assumed quantitative conversion) In DCM (1.5 mL) at 0 °C was added TFA (689 µL, 9 mmol). The cold bath was removed after 10 min. After 4 h at rt it was diluted with DCM (1.5 mL) and concentrated in vacuo. The crude residue was purified by reverse phase prep HPLC (X-Bridge, 30 x 100 mm, 5 µm, C18 column; acetonitrile-water with 0.1% formic acid modifier, 1 mL / min) to afford the title compound (2.7 mg, 3%). LCMS: m / z = 572.0 (M-1); 1< H NMR (400 MHz, D 2 O): δ 1< H NMR (400 MHz, D 2 O): δ 7.91 (s, 1H), 6.80 (s, 1H), 5.31 (d, J = 5.2 Hz, 1H), 4.54 (s, 1H), 4.35 (s, 2H), 3.50-3.35 (m, 2H), 1.19 (s, 3H), 1.18 (s, 3H).Reference Example 46: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-((2-(4-methylpiperazin-1-yl)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0427] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-((2-(4-methylpiperazin-1-yl)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. To a solution of Intermediate K (100 mg, 0.158 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 1 mL) at 0 °C was added 2-(4-methylpiperazin-1-yl)-N-(prop-2-yn-1-yl)acetamide (47 mg, 0.24 mmol), CuSO 4 (13 mg, 0.079 mmol) and sodium L-ascorbate (48 mg, 0.237 mmol). The resulting mixture was gradually brought to room temperature and stirred for 3 h. It was then diluted with EtOAc and brine and the layers were separated. The aqueous layer was extracted with EtOAc (3x) and the combined organic layers were washed with brine, dried over Na 2 SO 4 then concentrated in vacuo to afford crude title compound (110 mg, 84%); LCMS: m / z = 829.1 (M+1).

[0428] Step 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-((2-(4-methylpiperazin-1-yl)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0429] To a slurry of (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-((2-(4-methylpiperazin-1-yl)acetamido)methyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (120 mg, 0.13 mmol) In DCM (1.3 mL) at 0 °C was added TFA: DCM (1:1, 3.9 mL) followed by triethylsilane (62 µL, 0.39 mmol). The reaction mixture was stirred at 0 °C for 30 min and slowly warmed to room temperature. After 2 h at rt it was concentrated in vacuo and triturated with MTBE: Heptane (1:2) whereupon a solid was observed. The crude solid was purified by reverse phase prep HPLC (C18 column, ACN-water solvent system with 0.1% formic acid modifier) to afford the title compound (9 mg). LCMS: m / z = 669.75 (M-1); 1< H NMR (400 MHz, DMSO-d 6 ) δ 9.40 (d, J = 8.7 Hz, 1H), 8.25 (s, 1H), 8.00 (s, 1H), 7.33 (s, 2H), 6.71 (s, 1H), 5.29 (dd, J = 8.7, 5.6 Hz, 1H), 4.88-4.60 (m, 2H), 4.34 (d, J = 5.7 Hz, 2H), 4.24 (q, J = 5.3 Hz, 1H), 3.20-2.87 (m, 8H), 2.77 (s, 3H), 1.34 (s, 3H), 1.30 (s, 3H).Reference Example 47: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0430] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid . To a solution of Intermediate K (126 mg, 0.20 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 1.5 mL) at 0 °C was added propargyl alcohol (24 µL, 0.40 mmol), CuSO 4 (16 mg, 0.10 mmol) and sodium L-ascorbate (59 mg, 0.30 mmol). Th resulting mixture was gradually brought to rt and stirred for 3 h. It was then frozen and lyophilized. The crude residue was purified with HP21 resin (ACN-water, 10-100%) to afford the title compound as a light brown solid (100 mg, 73%); LCMS: m / z = 687.1 (M-1).

[0431] Step 2: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0432] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (100 mg, 0.145 mmol), DCM (4 mL) and TFA (1 mL, 13 mmol). The crude residue was purified by reverse phase prep HPLC (T3, 30 x 100 mm, 5 µm, C18 column; acetonitrile-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (22 mg, 29%) as a white solid. LCMS: m / z = 530.9 (M-1); 1< H NMR (400 MHz, DMSO-d 6 ): δ 12.50 (br s, 1H), 9.36 (d, J = 9.2 Hz, 1H), 7.97 (s, 1H), 7.50 (br s, 2H), 6.70 (s, 1H), 5.28 (dd, J = 8.8, 5.2, Hz, 1H), 4.86 (dd, J = 14.4, 4.0 Hz, 1H), 4.69 (dd, J = 14.8, 7.2 Hz, 1H), 4.48 (s, 2H), 4.27-4.21 (m, 1H), 1.35 (s, 3H), 1.34 (s, 3H).Reference Example 48: (2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-((4-(1-methylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate.

[0433] Step 1: 4-(1-(((2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)-1-methylpyridin-1-ium trifluoromethanesulfonate. To a solution of Intermediate K (85 mg, 0.134 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 1.0 mL) at 0 °C was added 4-ethynyl-1-methylpyridin-1-ium trifluoromethanesulfonate (72 µL, 0.27 mmol), CuSO 4 (11 mg, 0.067 mmol) and sodium L-ascorbate (40 mg, 0.201 mmol). The resulting mixture was gradually brought to rt and stirred for 3 h whereupon it was diluted with water (5 mL). The resulting precipitate was washed with water (2 mL) and dried via N 2 stream, affording the title compound (80 mg) as a mixture with its N-sulfonylated azetidinone analog as a light brown solid; LCMS: m / z = 748.1 (M-1).

[0434] Step 2: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(1-methylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate. 4-(1-(((2R,3S)-3-((Z)-2- (((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)-1-methylpyridin-1-ium trifluoromethanesulfonate (70 mg, 0.10 mmol) in DMF (1 mL) was treated with SO 3 •DMF (80 mg, 0.52 mmol). The reaction mixture was stirred at rt for 16 h then concentrated in vacuo and purified by HP21 resin (ACN-water, 10-100%), affording the title compound (24 mg, 31%) as a beige solid. LCMS: m / z = 748.1 (M-1).

[0435] Step 3: (2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-((4-(1-methylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate .

[0436] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(1-methylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate (24 mg, 0.032 mmol), DCM (1.2 mL) and TFA (0.3 mL, 3.9 mmol). The crude residue was purified by reverse phase prep HPLC (XBridge, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (7.9 mg, 41%) as a white solid. LCMS: m / z = 592.0 (M-1); 1< H NMR (400 MHz, D 2 O): δ 8.76 (s, 1H), 8.62 (d, J = 6.8 Hz, 2H), 8.19 (d, J = 6.4 Hz, 2H), 6.76 (s, 1H), 5.42 (d, J = 5.2 Hz, 1H), 4.98-4.81 (m, 2H; partially obscured by residual solvent peak), 4.66-4.54 (m, 1H assumed: obscured by residual solvent peak), 4.22 (s, 3H), 1.30 (s, 3H), 1.27 (s, 3H).Reference Example 49: (2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-((4-(1,3-dimethylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate.

[0437] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(1,3-dimethylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate. To a solution of intermediate K (120 mg, 0.19 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 1.5 mL) at 0 °C was added 4-ethynyl-1,3-dimethylpyridin-1-ium trifluoromethanesulfonate (107 mg, 0.38 mmol), CuSO 4 (15 mg, 0.095 mmol) and sodium L-ascorbate (56 mg, 0.285 mmol). The resulting mixture was gradually brought to rt and stirred for 3 h whereupon it was diluted with water (10 mL). The resulting precipitate was washed with water (5 mL) and dried. The crude residue was purified with HP21 resin (ACN-water, 10-100%), affording the title compound (80 mg, 55%) as a light brown solid; LCMS: m / z = 762.2 (M-1).

[0438] Step 2: (2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-2-((4-(1,3-dimethylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate.

[0439] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(1,3-dimethylpyridin-1-ium-4-yl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonate (24 mg, 0.032 mmol), DCM (1.2 mL) and TFA (0.3 mL, 3.9 mmol). The crude residue was purified by reverse phase prep HPLC (T3, 30 x 150 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (12 mg, 62%) as a white solid. LCMS: m / z = 606.1 (M-1); 1< H NMR (400 MHz, D 2 O): δ 8.65 (s, 1H), 8.57 (s, 1H), 8.49 (d, J = 5.6 Hz, 1H), 8.27 (d, J = 6.8 Hz, 1H), 6.74 (br s, 1H), 5.47 (d, J = 5.2 Hz, 1H), 4.97-4.88 (m, 3H), 4.21 (s, 3H), 2.46 (s, 3H), 1.30 (s, 3H), 1.28 (s, 3H).Reference Example 50: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0440] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazo)-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((4-(trimethylsilyl)-1H-1,2,3-triazol-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate. To a solution of Intermediate J (120 mg, 0.19 mmol) in a mixture of DMSO:water: tert-butanol (1:1:1, 2.0 mL) at 0 °C was added trimethylsilylacetylene (100 µL, 0.724 mmol), CuSO 4 (29 mg, 0.181 mmol) and sodium L-ascorbate (108 mg, 0.543 mmol). The resulting mixture was gradually brought to rt and stirred for 4 h, whereupon it was diluted with brine (5 mL) and extracted with EtOAc (3 x 10 mL). The combined oganic layers were dried over Na 2 SO 4 and concentrated in vacuo. The crude residue was purified via silica gel chromatoraphy (MeOH-DCM, 7%), affording the title compound (170 mg, 72%) as a light brown solid; LCMS: m / z = 651.2 (M+1).

[0441] Step 2: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate . Prepared according to the method described in WO2013 / 028590. To a solution of tert-butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxo-2-(((3S,4R)-2-oxo-4-((4-(trimethylsilyl)-1H-1,2,3-triazol-1-yl)methyl)azetidin-3-yl)amino)ethylidene)amino)oxy)-2-methylpropanoate (140 mg, 0.261 mmol) in THF (4 mL) was added TBAF (1M in THF, 860 µL, 0.86 mmol). After stirring at rt for 16 h, additional TBAF (1M in THF, 1.0 mL, 1.0 mmol) was added. After stirring for an another 48 h, the solution was concentrated in vacuo. The crude residue was purified via silica gel chromatography (MeOH-DCM, 7%) affording the title compound (84 mg, 68%) as an off white solid. LCMS: m / z = 579.2 (M+1).

[0442] Step 3: (2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid . tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (84 mg, 0.145 mmol) in DMF (2 mL) was treated with SO 3 •DMF (222 mg, 1.45 mmol). The reaction mixture was stirred at rt for 16 h then diluted with EtOAc (50 mL) and water. The layers were separated and the organic layer was washed with brine, dried over Na 2 SO 4 and concentrated in vacuo, affording the crude title compound as a light yellow solid (84 mg, 88%). LCMS: m / z = 657.1 (M-1) .

[0443] Step 4: 2-(((Z)-(2-(((2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid .

[0444] Followed the general procedure for the acid mediated deprotection using (2R,3S)-2-((1H-1,2,3-triazol-1-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (80 mg, 0.121 mmol), DCM (4 mL) and TFA (1 mL, 13 mmol). The crude residue was purified by reverse phase prep HPLC (T3, 30 x 150 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (12 mg, 20%) as a white solid. LCMS: m / z = 500.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 7.95 (s, 1H), 7.67 (s, 1H), 7.04 (s, 1H), 5.38 (d, J = 5.6 Hz, 1H), 4.88-4.80 (m, 1H), 4.78-4.70 (m, 2H assumed; obscured by solvent residual peak), 1.34 (s, 6H).Reference Example 51: 1-(((2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-4-oxo-1-sulfoazetidin-2-yl)methyl)-1H-1,2,3-triazole-4-carboxylic acid.

[0445] Step 1: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(tert-butoxycarbonyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid. To a solution of Intermediate K (157 mg, 0.248 mmol) in a mixture of DMSO: water: tert-butanol (1:1:1, 2.0 mL) at 0 °C was added tert-butyl propiolate (68 µL, 0.496 mmol), CuSO 4 (20 mg, 0.124 mmol) and sodium L-ascorbate (198 mg, 0.372 mmol). The resulting mixture was gradually brought to room temperature and stirred for 3 h, whereupon it was diluted with water (20 mL) and extracted with EtOAc (3 x 50 mL). The combined oganic layers were dried over Na 2 SO 4 , concentrated in vacuo dissolved in water and lyophilized, affording the title compound (180 mg, 96%) as a light yellow solid; LCMS: m / z = 759.3 (M+1).

[0446] Step 2: 1-(((2R,3S)-3-((Z)-2-(2-aminothiazol-4-yl)-2-(((2-carboxypropan-2-yl)oxy)imino)acetamido)-4-oxo-1-sulfoazetidin-2-yl)methyl)-1H-1,2,3-triazole-4-carboxylic acid.

[0447] Followed the general procedure for the acid mediated deprotection using (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(tert-butoxycarbonyl)-1H-1,2,3-triazol-1-yl)methyl)-4-oxoazetidine-1-sulfonic acid (180 mg, 0.237 mmol), DCM (8 mL) and TFA (2 mL, 26 mmol). The crude residue was purified by reverse phase prep HPLC (T3, 30 x 150 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (35 mg, 27%) as a white solid. LCMS: m / z = 544.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 8.43 (s, 1H), 6.99 (s, 1H), 5.38 (d, J = 5.2 Hz, 1H), 4.92-4.71 (m, 3H; partially obscured by solvent residual peak), 1.33 (s, 6H).Reference Example 52: 2-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0448] Step 1: tert-butyl 2-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate.

[0449] General procedure for the Mitsunobu reaction. To a solution of Intermediate H (300 mg, 0.569 mmol), tert-butyl ((2H-1,2,3-triazol-4-yl)methyl)carbamate (135 mg, 0.682 mmol) and triphenylphosphine (178 mg, 0.682 mmol) in THF (10 mL) at 0 °C was added DIAD (145 mg, 0.682 mmol), drop-wise. After stirring at rt for 16 h, the solution was concentrated and purified silica gel chromatography (MeOH-DCM, 2-5%), affording the title compound (300 mg, 75%) as a yellow foam. LCMS: m / z = 706.2 (M+1).

[0450] Step 2: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid . tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (220 mg, 0.311 mmol) in DMF (5 mL) was treated with SO 3 •DMF (476 mg, 3.11 mmol). The solution was stirred at rt for 48 h then then concentrated in vacuo and purified with HP21 resin (ACN-water, 10-50%), affording the title compound (82 mg, 33%). LCMS: m / z = 786.2 (M-1).

[0451] Step 3: 2-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0452] (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-(((tert-butoxycarbonyl)amino)methyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid (82 mg, 0.104 mmol) was stirred with formic acid (2.0 mL) at rt for 5 h, which removed both Boc groups. After concentration in vacuo, the material was dissolved in DCM (1.5 mL), cooled to 0 °C and treated with TFA (0.5 mL, 6.5 mmol) for 1 h, whereupon it was concentrated in vacuo. The crude residue was purified by reverse phase prep HPLC (T3, 30 x 150 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (17.2 mg, 31%) as a white solid. LCMS: m / z = 529.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 7.67 (s, 1H), 6.92 (s, 1H), 5.39 (d, J = 5.6 Hz, 1H), 4.86-4.74 (m, 3H assumed; obscured by solvent residual peak), 4.16 (s, 2H), 1.25 (s, 3H), 1.23 (3H, s).Reference Example 53: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-(guanidinomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0453]

[0454] To a solution of 2-(((Z)-(2-(((2R,3S)-2-((4-(aminomethyl)-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid (60 mg, 0.089 mmol) and pyrazole-1-carboxamide hydrochloride (16 mg, 0.11 mmol) in DMF (3 mL) was added DIPEA (45 µL, 0.27 mmol). After stirring for 16 h, the solution was concentrated and washed with ether. The crude residue was purified by reverse phase prep HPLC (XBridge, 30 x 150 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (7.5 mg, 15%) as a white solid. LCMS: m / z = 571.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 7.55 (s, 1H), 6.78 (s, 1H), 5.38 (d, J = 5.2 Hz, 1H), 4.82-4.76 (m, 1H assumed; obscured by solvent residual peak), 4.76-4.72 (m, 2H assumed; obscured by solvent residual peak), 4.32 (s, 2H), 1.15 (s, 3H), 1.14 (s, 3H).Reference Example 54: 2-(((Z)-(2-(((2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0455] Step 1: tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. The general procedure for the Mitsunobu reaction was followed using Intermediate H (300 mg, 0.569 mmol), 1,2,3-triazole (47 mg, 0.682 mmol), triphenylphosphine (178 mg, 0.682 mmol), DIAD (145 mg, 0.682 mmol) and THF (10 mL). Purified via silica gel chromatography (MeOH-DCM, 2-5%), affording the title compound (320 mg, 97%) as a yellow foam. LCMS: m / z = 579.2 (M+1).

[0456] Step 2: (2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid . tert-Butyl 2-(((Z)-(2-(((2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (320 mg, 0.553 mmol) in DMF (5 mL) was treated with SO 3 •DMF (846 mg, 5.53 mmol). The solution was stirred at rt for 24 h then then concentrated in vacuo and purified with HP21 resin (ACN-water, 10-50%), affording the title compound (70 mg, 19%). LCMS: m / z = 657.1 (M-1).

[0457] Step 3: 2-(((Z)-(2-(((2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-1-(2-aminothiazol-4-yl)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid .

[0458] (2R,3S)-2-((2H-1,2,3-triazol-2-yl)methyl)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-4-oxoazetidine-1-sulfonic acid (70 mg, 0.11 mmol) was stirred with formic acid (2.0 mL) at rt for 4 h then concentrated in vacuo. The crude residue was purified by reverse phase prep HPLC (XBridge, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (8.1 mg, 15%) as a white solid. LCMS: m / z = 500.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 7.60 (s, 2H), 6.94 (s, 1H), 5.39 (d, J = 5.2 Hz, 1H),), 4.83-4.78 (m, 2H), 4.78-4.68 (m, 1H assumed; obscured by solvent residual peak), 1.26 (s, 3H), 1.25 (s, 3H).Reference Example 55: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid.

[0459] Step 1: tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbony))amino)thiazo)-4-y))-2-(((2R,3S)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate. The general procedure for the Mitsunobu reaction was followed using Intermediate H (300 mg, 0.569 mmol), 4-methyl-1,2,3-triazole (83 mg, 0.683 mmol), triphenylphosphine (179 mg, 0.683 mmol), DIAD (138 mg, 0.648 mmol) and THF (8 mL). Purified via silica gel chromatography (MeOH-DCM, 2-4%), affording the title compound (160 mg, 47%) as a yellow foam. LCMS: m / z = 591 (M-1).

[0460] Step 2: (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid . tert-Butyl 2-(((Z)-(1-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)-2-(((2R,3S)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoate (160 mg, 0.270 mmol) in DMF (5 mL) was treated with SO 3 •DMF (413 mg, 2.70 mmol). The solution was stirred at rt for 16 h then then concentrated in vacuo and purified with HP21 resin (ACN-water, 10-50%), affording the title compound (77 mg, 43%). LCMS: m / z = 671.1 (M-1).

[0461] Step 3: 2-(((Z)-(1-(2-aminothiazol-4-yl)-2-(((2R,3S)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxo-1-sulfoazetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-methylpropanoic acid .

[0462] (2R,3S)-3-((Z)-2-(((1-(tert-butoxy)-2-methyl-1-oxopropan-2-yl)oxy)imino)-2-(2-((tert-butoxycarbonyl)amino)thiazol-4-yl)acetamido)-2-((4-methyl-2H-1,2,3-triazol-2-yl)methyl)-4-oxoazetidine-1-sulfonic acid (67 mg, 0.10 mmol) was stirred with formic acid (1.5 mL) at rt for 3.5 h then concentrated in vacuo. The crude residue was purified by reverse phase prep HPLC (XBridge, 30 x 100 mm, 5 µm, C18 column; ACN-water with 0.1% formic acid modifier, 1 mL / min), affording the title compound (13.7 mg, 27%) as a white solid. LCMS: m / z = 514.9 (M-1); 1< H NMR (400 MHz, D 2 O): δ 7.39 (s, 1H), 6.94 (s, 1H), 5.38 (d, J = 5.6 Hz, 1H)...

Claims

1. A compound of Formula (I): or a pharmaceutically acceptable salt thereof, wherein: Z is CR4 or N; R1 is H or C1-C4 alkyl; R2 is selected from the group consisting of H, C1-C4 alkyl, and -COOH or R1 and R2 taken together with the carbon to which they are attached form a ring selected from a C3-C6 cycloalkyl ring and a 4-6 membered heterocyclic ring containing up to two heteroatoms selected from N, O and S as ring members; R3 is selected from H, -COOH, and -L1-W-(CH2)0-2-X-R5; R4 is H or halo; each L1 is independently a straight chain or branched C1-4 alkylene; W is a bond, O, NH or S; X is phenyl, or a 5-6 membered heteroaryl ring containing 1-3 heteroatoms selected from N, O and S as ring members; where the phenyl and 5-6 membered heteroaryl are optionally substituted with one or two groups selected from C1-4 alkyl, hydroxy, -CN, F, C1-4 alkoxy, -NH2, -NH(C1-4 alkyl) and -N(C1-4 alkyl)2; R5 is selected from wherein R1b, R2b, and R3b are independently hydrogen, hydroxy, CN, (C1-C4)alkyl, (C1-C4)alkoxy, (C3-C6)cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member, wherein each (C1-C4)alkyl, (C1-C4)alkoxy, (C3-C6)cycloalkyl, or 4-, 5-, 6- or 7 -membered heterocyclyl containing N, O or S as a ring member may be substituted with one, two or three substituents selected independently from Y, and wherein R2b and R3b together with the nitrogen atom to which they are bonded can optionally form a 5- to 7-membered heterocyclyl including 0 or 1 further heteroatoms selected from N, O and S, said heterocyclyl optionally substituted by Y; Y is selected from F, CN, -NH2, Q, -L2-C(O)NR10-L2-Q, -L2-NR10-C(O)-L2-Q, -L2-OR10,-L2-N(R10)2, -L2-N+(R11)3, -L2-NR10-C(O)R10, -L2-NR10-L2-N(R10)2, -L2-O-C(O)OR10, -L2-O-C(O)-N(R10)2, -L2-NR10-C(O)-N(R10)2, -L2-NR10-C(O)-OR11, -L2-C(=NR10)-N(R10)2, -CON(R10)2, -L2-NR10-C(=NR10)-N(R10)2, -L2-NR10-C(=NR10)-R10, -L2-C(O)N(R10)2, , -L2-O-SO3R10; L2 is independently at each occurrence a bond or a straight chain or branched C1-4 alkylene, optionally substituted with NH2, OH, or F; Het is a 4-6 membered saturated heterocyclic ring, where the heterocyclic ring contains 1 or 2 heteroatoms selected from N, O and S as ring members and is substituted with oxo and optionally further substituted with Y; R10 and R12 are independently H or C1-4 alkyl optionally substituted by one or two groups selected from OH, NH2 or Q; Q is selected from -L2-N(R13)2, -L2-N+(R14)3, -L2-NR13-C(=NR13)-N(R13)2, -L2-NR13-CR13(=NR13), -L2-NR13-L2-Cy, -L2-NR13-C(=NR13)-NR13-L2-Cy, -L2-NR13-C(=NR13)-L2-Cy, -L2-Cy-L2-R13, -L2-Cy-L2-N(R13)2, -L2-NR13-SO2-N(R13)2, -L2-SO2-N(R13)2, -L2-NR13-SO2-R13, -L2-NR13-L2-Ar, -L2-S-L2-Cy, -L2-NR13-(C=O)-O-R13, each Cy is independently a 3-6 membered cycloalkyl or 3-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as a ring member and optionally fused to a 5-6 membered aryl or heteroaryl ring, wherein each Cy is optionally substituted with one or two groups selected from halo, C1-3 haloalkyl, R14, hydroxy, C1-4 alkoxy, -NH2, -NH(C1-4 alkyl) or -N(C1-4 alkyl)2; Ar is phenyl, optionally substituted with one or two groups selected from halo, C1-3 haloalkyl, R14, hydroxy, C1-4 alkoxy, -NH2, -NH(C1-4 alkyl) or -N(C1-4alkyl)2; R11 is independently at each occurrence C1-4 alkyl; and two R10 , or two R11 , or two R12 on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C1-4 alkyl, C1-4 alkoxy, hydroxy, or oxo; R13 is independently at each occurrence H or C1-4 alkyl optionally substituted with hydroxy, -OR14, -NHR14, C1-4 alkoxy, -NH2, -NH(C1-4 alkyl) or -N(C1-4 alkyl)2; R14 is independently at each occurrence C1-4 alkyl optionally substituted with hydroxy, C1-4 alkoxy, -NH2, -NH(C1-4 alkyl) or -N(C1-4 alkyl)2; wherein two R13 or two R14 on the same N can cyclize to form a 4-6 membered heterocyclic ring optionally substituted with C1-4 alkyl, C1-4 alkoxy, hydroxy, amino or oxo; R15 is H, halo, C1-4 alkyl, CN, or -O(C1-4 alkyl).

2. The compound of claim 1, wherein R1 and R2 together with the carbon to which they are both attached form a cyclopropane ring and R3 is -COOH.

3. The compound of any of the preceding claims, wherein Z is CH.

4. The compound of any of claims 1-3, wherein Het is selected from pyrrolidine-2-one, oxazolidin-2-one, and imidazolidin-2-one, and is optionally substituted with Y.

5. The compound of any of the preceding claims, having the structure of Formula (II): or a pharmaceutically acceptable salt thereof.

6. The compound of claim 1, wherein ---O-CR1R2R3 is selected from and 7. The compound of claim 1 or claim 6, wherein Het is selected from 8. The compound of any of the preceding claims, which is a pharmaceutically acceptable salt.

9. The compound of claim 1, which is selected from: 1 2 14 3 57 21 22 24 63 59 58 25 26 64 70 72 76 80 86 88 97 104 108 111 113 122 and the pharmaceutically acceptable salts thereof.

10. The compound of claim 1, which is 22 or a pharmaceutically acceptable salt thereof.

11. A pharmaceutical composition comprising a compound of any of the preceding claims and at least one pharmaceutically acceptable excipient.

12. A compound according to any of claims 1-10, or a pharmaceutical composition of claim 11 for use in a method to treat a Gram-negative bacterial infection.

13. The compound or pharmaceutical composition for use according to claim 12, wherein the bacterial infection is nosocomial pneumonia, an intraabdominal infection, or a urinary tract infection caused by a species of Enterobacteriaceae.

14. A compound according to any of claims 1-10 for use in therapy.

15. A pharmaceutical combination, comprising a compound according to any of claims 1-10 and a second therapeutic agent.