Lipidated polymyxin analogues

Abstract

The present invention relates to polymyxin analogs that contain unique lipids anchored through a novel 2-thioethyl ester bond via the peptide backbone.

Description

[Technical field]

[0001] The present invention relates generally to polymyxin analogs that contain unique lipids anchored through a novel 2-thioethyl ester bond via the peptide backbone. [Background technology]

[0002] The world needs new antibiotics. Since the "Golden Age" of antibiotic discovery (1940-1960), antibiotic research has slowed significantly, with only 30 new compounds having advanced to clinical use in the past 20 years. This looming antibiotic crisis is further complicated by the growing resistance of some Gram-negative bacteria, such as Escherichia coli and Pseudomonas aeruginosa, to current frontline antibiotics. Gram-negative infections are more complex to treat due to the cellular structure of the pathogens, which have a low-permeability double-membrane cell envelope. Unfortunately, most of the newly approved antibiotics are directed at Gram-positive bacteria, and few of the antibiotics remaining in the clinical pipeline target Gram-negative bacteria.

[0003] Thus, there is a need for new and improved antibiotics that can effectively target additional species and strains of pathogenic bacteria, particularly gram-negative pathogenic bacteria.

[0004] It is an object of the present invention to at least go some way towards meeting this need and / or at least provide the public with a useful choice by providing at least one new and improved antibiotic that can effectively target pathogenic bacteria, particularly gram-negative pathogenic bacteria. Other objects of the present invention will become apparent from the following description, which is given by way of example only.

[0005] References are made herein to external sources, including patent specifications and other documents, generally for the purpose of providing a context for discussing the features of the present invention. In any jurisdiction, unless otherwise stated, the citation to such sources shall not be construed as an admission that such sources are prior art or form part of the common general knowledge in the field. Summary of the Invention

[0006] The present invention relates to novel polymyxin analogs that contain one or more unique lipids anchored through a peptide backbone by novel 2-thioethyl ester bonds.

[0007] In one aspect, the present invention relates to a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof:

[0008] [ka] (however, A is, [ka] [ka] and [ka] is selected from Here, R 1 is H or -C(O)-(C1-C 10 ) alkyl, n is 1 or 2, and R 5 is H or CH3, X1 is absent or a dab X2 is Thr, X3 is selected from the group consisting of Dab, Dap, or D-Ser; X4G is selected from the group consisting of Dab, Lys, Orn, or Dap; X6 is D-Phe, or [ka] and X7 is Leu or [ka] and Here, R 2 , R 3 , and R 4 are independently, -(C2~C 10 )Alkyl, -(C3-C 10 ) Cycloalkyl, aryl, aryl (C1-C 10 )Alkyl, -(C1-C 10 ) Alkylaryl, pyridinyl (C1-C 10 ) alkyl, and -(C1-C 10 ) alkylpyridinyl; Here, -(C3~C 10 ) cycloalkyl, aryl, and pyridinyl are each independently halo, -(C1-C6)alkyl, -(C3-C6)cycloalkyl, -O-(C1-C6)alkyl, -O-(C3-C6)cycloalkyl, -S(C1-C6)alkyl, - optionally substituted with S(C3-C6)cycloalkyl, -NH(C1-C6)alkyl, or NH-(C3-C6)cycloalkyl; R 6 and R 7 are independently selected from H or CH3.

[0009] In another aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) and a pharma- ceutically acceptable carrier.

[0010] Another aspect The present invention provides a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof for treating or preventing a bacterial infection in a subject.

[0011] In another aspect, the present invention provides a method of treating or preventing a bacterial infection in a subject, comprising administering to the subject a therapeutically effective amount of a compound of formula (I) or a pharma-ceutically acceptable salt or solvate thereof.

[0012] In another aspect, the present invention provides the use of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof in the manufacture of a medicament for the treatment or prophylaxis of a bacterial infection in a subject.

[0013] In the above aspects, in one embodiment, the bacterial infection is a gram-negative infection.

[0014] In another aspect, the present invention provides a method of killing bacteria comprising contacting the bacteria with a bactericidal amount of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof.

[0015] In another aspect, the present invention provides a method of inhibiting bacterial growth comprising contacting the bacteria with a bacteriostatic amount of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof.

[0016] In the above aspects, in one embodiment the bacterium is a gram-negative bacterium.

[0017] Reference to a numerical range disclosed herein (e.g., 1-10) includes all rational numbers within this range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) and any rational range within this range (e.g., 2-8, 1.5-5.5, and 3.1-4.7), such that all subranges of every range explicitly disclosed herein are expressly disclosed herein. These are merely examples of specific intent, and all possible combinations of numerical values ​​between the lowest and highest values ​​recited should be considered as being expressly set forth herein in a similar manner.

[0018] Although the present invention has been generally defined above, it will be appreciated by those skilled in the art that the present invention is not limited thereto, and further includes the embodiments described in the following embodiments. [Brief description of the drawings]

[0019] The present invention will now be described with reference to the accompanying drawings. [Figure 1] FIG. 1 is a scheme showing a solid-phase synthesis strategy using S-lipidated building blocks for the preparation of S-lipidated analogs of polymyxin B. Reagents and conditions: ii) iterative FmocSPPS, 20% piperidine in DMF (v / v), 2x5 min, rt, then Fmoc-Xaa-OH, HATU, DIPEA, DMF, 20 min, rt; ii) 20% piperidine in DMF (v / v), 2x5 min, rt; iii) building blocks, 3a-3f, DIPEA, DMF, 1 h, rt; iii) 20% piperidine in DMF, iv) Boc2O, DMF, 2 h; v) 2% N2H4.H2O in DMF, 3x5 min, rt. vi) Fmoc-Thr(tBu)-OH, HATU, DIPEA, DMF, 20 min, vii) Pd(PPh3)4, PhSiH3, CH2Cl2:DMF (1:1, v / v), 3 h, room temperature. viii) 20% piperidine (v / v) in DMF, 2 x 5 min, room temperature. ix) PyBOP, HOAt, NMM, DMF, 12 hours, room temperature. x) 90% TFA, 5% TIPS, 5% H2O (v / v / v), 2 hours, room temperature. [Diagram 2]FIG. 14 is a scheme showing a solid-phase synthesis strategy for the preparation of bis-S-lipidated polymyxins using an off-resin lipidation strategy. Reagents and conditions: i) iterative FmocSPPS, 20% piperidine in DMF (v / v), 2x5 min, rt, then Fmoc-Xaa-OH, HCTU, DIPEA, DMF, 20 min, rt; ii) 20% piperidine in DMF (v / v), 2x5 min, rt; iii) Boc2O, DMF, 20 min, rt; iv) NH2OH·HCl, imidazole, NMP, 5 h, rt; v) Fmoc-Thr(tBu)-OH, HCTU, DIPEA, DMF, 20 min, rt; vi) Pd(PPh3)4, PhSiH3, CH2Cl2, 3 h, rt; vii) 20% piperidine in DMF (v / v), 2x5 min, rt. viii) PyBOP, HOAt, DIPEA, DMF, 12 h, rt; ix) 94% TFA, 2% TIPS, 2% H2O, 2% EDT (v / v / v / v), 2 h, rt. x) vinyl ester, DMPA, TIPS, tert-nonanethiol, 5% TFA in NMP (v / v), 1 h, 365 nm, rt; xi) AgOAc, 50% CH3CN in H2O (v / v), 12 h, rt, then DTT, 50% CH3CN in H2O (v / v), 1 h, rt; xii) vinyl ester, DMPA, TIPS, tert-nonanethiol, 5% TFA in NMP (v / v), 1 h, 365 nm, rt. [Diagram 3]Figure 14 Scheme showing alternative solid-phase synthesis of mono S-lipidated polymyxins with different exocyclic moieties and cysteinyl handles. Reagents and conditions: i) iterative FmocSPPS, 20% piperidine in DMF (v / v), 2 x 5 min, rt, then Fmoc-Xaa-OH, HATU, DIPEA, DMF, 20 min, rt; ii) NH2OH.HCl, imidazole, NMP, 5 h, rt; iii) Alloc-Thr(tBu)-OH, DIC, HOAt, DMF, 16 h; iv) Pd(PPh3)4, PhSiH3, CH2Cl2, 3 h; v) PyAOP, HOAt, DIPEA, DMF , 12 h, rt; vi) repeated FmocSPPS, 20% piperidine in DMF (v / v), 2x5 min, rt, then Fmoc-Xaa-OH, HATU, DIPEA, DMF, 20 min, rt, for A, either Fmoc-Cys(Trt)-OH or Fmoc-D-Cys(Trt)-OH or TrtSCH2CH2CO2H, or homo-L-Cys(Trt)-OH, HATU, HOAt, DIPEA, DMF:DCM (1:1), 1 h; viii) 20% piperidine in DMF (v / v), 2x5 min; ix) 95% TFA, 2% TIPS, 1% HO, 2% EDT (v / v / v / v), 2 h, rt. x) Vinyl propionate, DMPA, TIPS, tert-nonanethiol, 5% TFA in NMP (v / v), 1 h, 365 nm, room temperature. [Figure 4] Scheme showing chemoenzymatic solution-phase synthesis for the preparation of mono S-lipidated polymyxins. i) Enzymatic hydrolysis, papain (1.5–10 units / mg), DTT, phosphate buffer (0.1 M, pH 6.8), 28 h, 37 °C. ii) Boc-ON, NEt3, MeOH:H2O (2:1 v / v), 30 min, room temperature. iii) Boc-L-Thz-OH or Boc-D-Thz-OH, HATU, DIPEA, CH2Cl2, 2 h, room temperature. iv) TFA:CH2Cl2 (1:1 v / v), 1 h, room temperature. v) MeONH2·H2O solution (0.2 M, pH 4), 24 h, room temperature or 37 °C. vi) Vinyl esters, TIPS, tert-nonanethiol, DMPA, 5% TFA in NMP (v / v), 365 nm, 1 h, room temperature. [Diagram 5]Graph showing quantification of apoptosis. Apoptotic (TUNEL+) cells are quantified on paraffin sections of polymyxin-treated organoids (100-1 mM polymyxin B and compounds 29 and 35). n is ≥10 organoids per condition. ****p-value ≤ 0.0001, one-way ANOVA. [Figure 6] Figure 1 is a graph showing cell survival as a function of the indicated compound concentration. Data are representative of triplicate experiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] 5.1 Definition The term "comprising", as used herein, means "consisting at least in part of". In interpreting each "comprising" term in this specification and in each claim, there may be features other than those present in the section or preceding section. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

[0021] As used herein, the term "and / or" means "and" or "or," or both.

[0022] As used herein, "(plural)" following a noun refers to the complex and / or singular form of the noun.

[0023] Asymmetric centers may exist in the compounds described herein. The asymmetric centers may be designated as (R) or (S), depending on the placement of the substituents in three-dimensional space at the chiral carbon atom. All chiral, diastereomeric and racemic forms of the structures are intended unless a specific stereochemistry or isomeric form is indicated. All stereochemical isomeric forms of the compounds, including diastereomeric, enantiomeric and epimeric forms, as well as d- and l-forms, and mixtures thereof, including enantiomerically enriched and diastereomerically enriched stereochemical isomeric mixtures, are within the scope of the present invention. Thus, the present invention relates to compounds in substantially pure stereoisomeric form, e.g., greater than about 90%, from about 95% to about 97%, or greater than 99%, with respect to the asymmetric center of the amino acid residue. Such diastereomers can be prepared, for example, by asymmetric synthesis using chiral intermediates, or the mixtures can be resolved using chromatography or other conventional methods.

[0024] Individual enantiomers can be prepared synthetically from commercially available enantiomerically pure starting materials, or by preparing an enantiomeric mixture and resolving the mixture into the individual enantiomers. Resolution methods include (a) separation of the enantiomeric mixture by chromatography on a chiral stationary phase, and (b) conversion of the enantiomeric mixture to a diastereomeric mixture, and separation of the diastereomers, for example by recrystallization or chromatography and any other suitable method known in the art. Starting materials of determined stereochemistry can be commercially obtained or prepared, and, if necessary, resolved by techniques known in the art. Enantiomers with the "natural" configuration at the chiral carbon (the carbon bearing the CH2-LG moiety in seco form) are preferred.

[0025] The compounds described herein may also exist as conformational or geometric isomers, including cis, trans, syn, anti, entgegen (E) and zusammen (Z) isomers, all of which are within the scope of the present invention, as well as any mixtures thereof.

[0026] Also within the scope of the present invention are any tautomers or mixtures of the described compounds.As one skilled in the art will appreciate, various functional groups and other structures may exhibit tautomerism.Examples include, but are not limited to, ketone / enol, imine / enamine, thione / enethiol tautomers.

[0027] The compounds described herein may also exist as isotopologues and isotopomers, where one or more atoms in the compounds are substituted with different isotopes. Suitable isotopes include, for example, 1 H, 2 H(D), 3 H(T), 12 C. 13 C. 14 C. 16 O, and 18 O. Methods for incorporating such isotopes into the compounds described herein will be apparent to one of ordinary skill in the art, and isotopologues and isotopomers of the compounds described herein are also within the scope of the present invention.

[0028] The scope of the present invention also includes pharma- ceutically acceptable salts, salts of the compounds described herein. These salts include acid addition salts, base addition salts, and quaternary salts containing basic nitrogen groups. Acid addition salts can be prepared by reacting the free base form of the compound with an inorganic or organic acid. Examples of inorganic acids include, but are not limited to, hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, and the like. Examples of organic acids include, but are not limited to, acetic acid, trifluoroacetic acid, propionic acid, succinic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, maleic acid, fumaric acid, pyruvic acid, aspartic acid, glutamic acid, stearic acid, salicylic acid, methanesulfonic acid, benzenesulfonic acid, isethionic acid, sulfonic acid, adipic acid, butyric acid, pivalic acid, and the like. Base addition salts can be prepared by reacting the free acid form of the compound with an inorganic or organic base. Examples of inorganic base addition salts include alkali metal salts, alkaline earth metal salts, and other physiologically acceptable metal salts such as aluminum, calcium, lithium, magnesium, potassium, sodium, or zinc salts. Examples of organic base addition salts include amine salts such as, for example, trimethylamine, diethylamine, ethanolamine, diethanolamine, and ethylenediamine salts. Quaternary salts of basic nitrogen-containing groups in the compounds can be prepared, for example, by reacting the compounds with alkyl halides such as methyl, ethyl, propyl, and butyl chlorides, bromides, and iodides, and dialkyl sulfates such as dimethyl, diethyl, dibutyl, and diamyl sulfates.

[0029] The compounds described herein may form or exist as solvates with various solvents. As used herein, the term "solvate" refers to an association of one or more solvent molecules with a compound described herein, unless otherwise indicated. When the solvent is water, the solvate may be referred to as a hydrate, e.g., a monohydrate, a dihydrate, a trihydrate. All dissolved and undissolved forms of the compounds described in this section are within the scope of the invention. General chemical terms used herein have their ordinary meanings.

[0030] Standard abbreviations for chemical groups are well known in the art and have their common meaning, e.g., Me=methyl, Et=ethyl, Bu=butyl, t-Bu=t-butyl, Cys=cysteine, Ph=phenyl, Leu=leucine, Phe=phenylalanine, Thr=threonine, Dab=2,4-diaminobutanoic acid, Dap=2,3-diaminopropionic acid, DMF=dimethylformamide, Orn=2,5-diaminovaleric acid, DIPEA=N,N-diisopropylethylamine, Fmoc=9-fluorenylmethoxycarbonyl , Boc = t-butyl-butoxycarbonyl, HATU = 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate, PyBOP = benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, HOAt = 1-hydroxy-7-azabenzotriazole, NMM = N-methylmorpholine, and TFA = trifluoroacetic acid.

[0031] Unless otherwise stated, these abbreviations apply to all of the following examples.

[0032] Unless otherwise stated, the term "alkyl" as used herein alone or in combination with other terms refers to a straight or branched chain, saturated or unsaturated, acyclic hydrocarbon group. In some embodiments, an alkyl has 1-15, 1-13, 1-11, 1-10, 1-8, 1-6, 1-5, 1-4, 1-3, 1-2, 2-12, 2-9, 2-8, 2-6, 2-4, 3-9, 3-8, 4-9, 4-15, 6-15, 8-15, 10-15, or 1, 2, or 3 carbon atoms. In some embodiments, an alkyl is saturated. Examples of such alkyls include -methyl, -ethyl, -n-propyl, -n-butyl, -n-pentyl, -n-hexyl, -n-heptyl, -n-octyl, -n-nonyl, -n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, -isopropyl, -sec-butyl, -isobutyl, -tert-butyl, -isopentyl, -neopentyl, 2-methylbutyl, -isohexyl, 2-methylpentyl, 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 2, Examples of alkyl include, but are not limited to, 2-dimethylpentyl, 2,3-dimethylpentyl, 3,3-dimethylpentyl, 2,3,4-trimethylpentyl, 3-methylhexyl, 2,2-dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 3,5-dimethylhexyl, 2,4-dimethylpentyl, 2-methylheptyl, 3-methylheptyl, n-heptyl, isoheptyl, isooctyl, isononyl, isodecyl, isododecyl, isotridecyl, isotetradecyl, and isopentadecyl. In some embodiments, the alkyl is unsaturated. Examples of such alkyls include, but are not limited to, -vinyl, -allyl, -1-butenyl, -2-butenyl, -isobutylenyl, -1-pentenyl, -2-pentenyl, -3-methyl-1-butenyl, -2-methyl-2-butenyl, -2,3-dimethyl-2-butenyl, 1-hexyl, 2-hexyl, 3-hexyl, -acetylenyl, -propynyl, -1-butynyl, -2-butynyl, -1-pentynyl, -2-pentynyl, -3-methyl-1-butynyl, and the like. x"-Cy", where x and y are both integers, when used in conjunction with the term "aryl", refers to the number of cyclic carbon atoms in the aryl.

[0033] Unless otherwise stated, the term "cycloalkyl," as used herein alone or in combination with other terms, refers to a monocyclic or polycyclic (e.g., fused, bridged, or spiro) non-aromatic hydrocarbon group. In some embodiments, cycloalkyl is saturated. The prefix "C x "-Cy" (x and y are integers), when used in conjunction with the term "cycloalkyl", refers to the number of ring carbon atoms in the cycloalkyl.

[0034] The term "aryl" as used herein means a cyclic aromatic hydrocarbon group that does not contain a ring heteroatom. Aryl includes monocyclic and bicyclic ring systems. Examples of aryl include, but are not limited to, phenyl, azulenyl, heptalenyl, biphenyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, indanyl, pentalenyl, and naphthyl. In some embodiments, an aryl has 6-20, 6-14, 6-12, or 6-10 carbon atoms in the ring. In some embodiments, an aryl is phenyl or naphthyl. Aryl includes aromatic carbocyclic fused ring systems. Examples include, but are not limited to, indanyl and tetrahydronaphthyl. The prefix "C" is used to denote a cyclic ring system that is fused to a ring. x "-Cy," where x and y are both integers, when used in conjunction with the term "aryl," refers to the number of cyclic carbon atoms in the aryl. In one embodiment, the aryl is phenyl.

[0035] The term "pyridinyl," as used herein alone or in combination with other terms, unless otherwise indicated, refers to an aromatic six-membered ring containing one nitrogen atom.

[0036] The term "heteroatom" is intended to include oxygen, nitrogen, sulfur, selenium, or phosphorus. In some embodiments, the heteroatom is selected from the group consisting of oxygen, nitrogen, and sulfur.

[0037] The term "halo" as used herein alone or in combination with other terms, means fluorine, chlorine, bromine and iodine, preferably fluorine, chlorine and bromine, more preferably fluorine and chlorine.

[0038] The term "amino acid" as used herein refers to a molecule that contains both an amino group and a carboxyl group attached to a carbon atom called the alpha carbon. Amino acids may be naturally occurring or non-naturally occurring. Naturally occurring amino acids include, but are not limited to, the protein amino acids known by the single letter abbreviations A, R, N, C, D, Q, E, G, H, I, L, K, M, F, P, S, T, W, Y and W, as well as the three letter abbreviations Phe, Leu, Ser, Gly, Cys, etc. Non-naturally occurring amino acids may also form or be included in peptide chains by linkage through the amino or carboxyl groups. Non-naturally occurring amino acids include Dab, Dap, and Orn. ​​The present invention contemplates the use of both L- and D-forms of amino acids, including compounds incorporating both L- and D-forms of the same amino acid. Unless otherwise stated, the amino acids described for use in the present invention are L-amino acids.

[0039] As used herein, the term "pharmaceutically acceptable salt" refers to a pharmaceutically acceptable organic or inorganic salt of a compound described herein, unless otherwise specified. For example, the compounds described herein may contain an amino group and thus may form acid addition salts with this amino group. Examples of salts include, but are not limited to, sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, hydrogen sulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate (i.e., 1,1'-methylenebis-(2-hydroxy-3-naphthoic acid)) salts. Pharmaceutically acceptable salts may contain other molecules such as acetate, succinate, or other counterions. The counterion may be any organic or inorganic moiety that stabilizes the charge of the parent compound. Furthermore, a pharma- ceutically acceptable salt may have multiple charged atoms in its structure. When multiple charged atoms are part of the pharma- ceutically acceptable salt, it may have multiple counter ions. Thus, a pharma- ceutically acceptable salt may have one or more charged atoms and / or one or more counter ions.

[0040] The term "therapeutically effective amount" as used herein in reference to an antimicrobial compound or composition is an amount sufficient to achieve at least an alleviation of symptoms associated with the bacterial infection being or to be treated, or an amount sufficient to achieve a reduction in bacterial growth, or an amount sufficient to increase the susceptibility of the bacteria to other therapeutic agents or to innate immunological clearance.

[0041] The term "bactericidal amount" as used in the context of the antimicrobial compounds or compositions described herein is an amount sufficient to kill bacteria.

[0042] As used herein, a "bacteriostatic amount" in reference to an antimicrobial compound or composition is an amount sufficient to retard the growth of bacteria.

[0043] As used herein, the terms "treatment" and "treating" include any treatment for a disorder or disease in an animal subject (preferably a mammal, more preferably a human), including: (i) inhibiting a bacterial infection, e.g., inhibiting bacterial growth, (ii) alleviating a bacterial infection (e.g., reducing the severity of an infection), or (iii) alleviating a disorder resulting from a bacterial infection, e.g., a symptom of an infection. As used herein, the terms "prophylaxis" and "preventing" include prophylaxis or prevention of a disorder or disease in an animal subject (preferably a mammal, more preferably a human), including preventing the development of a bacterial infection in a subject who may be susceptible to infection but has not been diagnosed with the infection.

[0044] 5.2 DNA-PK Inhibitor Compounds of the Invention Polymyxins are a class of cyclic lipopeptides that are effective antibacterial agents selectively against major Gram-negative pathogens such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Due to side effects and the introduction of safer alternatives, they were gradually withdrawn from clinical use in the 1970s. However, the rapid increase in Gram-negative resistance to known antibiotics has since led to the re-emergence of polymyxins as frontline antibiotics.

[0045] [ka]

[0046] [ka] Polymyxin B (1) and polymyxin nonapeptide (1a)

[0047] Structurally, polymyxins consist of a central cyclic heptapeptide core and a linear tripeptide or dipeptide spacer terminating in an N-acylated lipid (see polymyxin B, 1 and polymyxin B nonapeptide, 1a above). They are defined by the lipid length and branching, the hydrophobic amino acids at positions 6 and 7, and the polycationic nature of the non-canonical amino acid 2,4-diaminobutyric acid (Dab) present in the cyclic core and cyclic tail. Two polymyxins, polymyxin B and polymyxin E (also called colistin), are used clinically for multidrug-resistant Gram-negative bacterial infections, despite associated neuro- and nephrotoxicity, requiring careful dosing and renal monitoring.

[0048] We have prepared a series of polymyxin B and polymyxin nonapeptide analogs containing specialized lipids anchored by novel 2-thioethyl ester bonds at the N-terminus, 6-position, 7-position, or a combination of several sites through the peptide backbone. We found that these compounds have similar activity to polymyxin B and exhibit reduced nephrotoxicity.

[0049] Thus, in one aspect, the present invention relates to a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof:

[0050] [ka] (however, A is, [ka] [ka] and [ka] is selected from Here, R 1 is H or -C(O)-(C1-C 10 ) alkyl, n is 1 or 2, and R5 is H or CH3, X1 is absent or a dab X2 is Thr; X3 is selected from the group consisting of Dab, Dap, or D-Ser; X4G is selected from the group consisting of Dab, Lys, Orn, or Dap; X6 is D-Phe or [ka] and X7 is Leu or [ka] and Here, R 2 , R 3 , R 4 are independently, -(C2~C 10 )Alkyl, -(C3-C 10 ) Cycloalkyl, aryl, aryl (C1-C 10 )Alkyl, -(C1-C 10 ) Alkylaryl, pyridinyl (C1-C 10 ) alkyl, and -(C1-C 10 ) alkylpyridinyl; Here, -(C3~C 10 ) cycloalkyl, aryl and pyridyl are each independently halo, -(C1-C6)alkyl, -(C3-C6)cycloalkyl, -O-(C1-C6)alkyl, -O-(C3-C6)cycloalkyl, -S(C1-C6)alkyl, - optionally substituted with S(C3-C6)cycloalkyl, -NH(C1-C6)alkyl, or NH-(C3-C6)cycloalkyl; R 6 and R 7 are independently selected from H or CH3.

[0051] In one embodiment, X is A1. In one embodiment, X is [ka] It is.

[0052] In one embodiment, A1 is [ka] where n is 1 and X1 is Dab.

[0053] In one embodiment, A1 is [ka] where n is 1 and X1 is absent.

[0054] In one embodiment, A is A2. In one embodiment, A is A2 and n is 1.

[0055] In one embodiment, A is A3. In one embodiment, A3 is [ka] It is.

[0056] In one embodiment, R 2 , -(C2~C 10 )Alkyl, -(C3-C 10 ) Cycloalkyl, aryl, aryl (C1-C 10 ) alkyl, and -(C1-C 10 ) alkylaryl.

[0057] In one embodiment, R 1 is H.

[0058] In one embodiment, X1 is Dab.

[0059] In one embodiment, X3 is a Dab.

[0060] In one embodiment, X4 is Lys or Dab.

[0061] In one embodiment, X6 is D-Phe.

[0062] In one embodiment, X7 is Leu.

[0063] In one embodiment, A is A1, n is 1, and R 2 , -(C2~C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl; R 1 is H or -C(O)-(C1-C 10 ) alkyl, X1 is Dab, X2 is Thr, X3 is Dab, X4 is Dab or Lys, and X6 is D-Phe or [ka] where R 3 , -(C2~C 10 )Alkyl, -(C3-C 10 ) Cycloalkyl, aryl, aryl (C1-C 10 ) alkyl, and -(C1-C 10 ) alkylaryl, preferably -(C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl, and X7 is Leu or [ka] where R 4 , -(C2~C 10 )Alkyl, -(C3-C 10 ) Cycloalkyl, aryl, aryl (C1-C 10 ) alkyl, and -(C1-C 10 ) alkylaryl, preferably -(C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl. Preferably, R 2 , -(C2~C 10 ) alkyl.

[0064] In one embodiment, A is A1, n is 1, and R 2 , -(C2~C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl; R 1 is H, X1 is absent, X3 is Dab, Dap or D-Ser, X4 is Dab, X6 is D-Phe and X7 is Leu. 2 , -(C2~C 10 ) alkyl.

[0065] In one embodiment, A is A2, n is 1, and R 2 , -(C2~C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl; R 1 is H, X1 is Dab, X3 is Dab, X4 is Dab or Lys, X6 is D-Phe and X7 is Leu. 2 , -(C2~C 10 ) alkyl.

[0066] In one embodiment, A is A1, n is 2, and R 2 , -(C2~C 10 ) Alkyl, aryl, and aryl (C1-C 10 ) alkyl; R 1 is H, X1 is Dab, X3 is Dab, X4 is Dab or Lys, X6 is D-Phe and X7 is Leu. 2 Ha-(C2~C 10 ) alkyl.

[0067] In another aspect, the present invention provides a compound selected from the group consisting of a polymyxin analogue as defined in any of Tables 1 and 3, or a pharma- ceutically acceptable salt or solvate thereof.

[0068] In one embodiment, the compound of formula (I) is selected from the group consisting of 29, 44, 59, 60, 76, and 79;

[0069] [ka] or a pharma- ceutically acceptable salt or solvate thereof.

[0070] Any embodiment of the invention described herein relates to any aspect of the invention described herein. The embodiments and preferences described herein may be relevant alone or in combination with any two or more of any aspect of the invention described herein.

[0071] The polymyxin B and polymyxin nonapeptide analogs of the invention can be prepared using solid-state peptide synthesis (SSPS) by incorporating one or more lipidated cysteine ​​residues into the structure via a novel 2-thioethyl ester linkage to the peptide backbone.

[0072] The 2-thioethyl ester bond is a linker between the free mercaptan of a cysteine ​​residue and the terminal sp on a fatty acid vinyl ester. 2 Using the radical mercaptan-ene reaction between carbon atoms, the inventor's unique ClipPA ( peptide or amino acid Above ( Cysteine ​​lipidation ) technology (Yang, Harris, Williams, Brimble, 2016) (Wright et al., 2013).

[0073] The vinyl ester components can be prepared by refluxing the corresponding vinyl carboxylate acetate in the presence of mercuric acetate (Hg(OAc)2) and sulfuric acid as described by Magrone et al. (Magrone, Cavallo, Panzeri, Passarella, & Riva, 2010).

[0074] Once prepared, the lipidated cysteine ​​residue is incorporated into the peptide chain that constitutes the polymyxin B or polymyxin nonapeptide analog.

[0075] The lipidated L-cysteine ​​residue at the N-terminus of the compound may be replaced with a cysteine ​​variant such as D-Cys, Desamino-Cys (sulfhydrylpropanoic acid) or HomoCys (4-amino-4-sulfanylbutanoic acid).

[0076] The polymyxin peptide framework can be prepared using any peptide synthesis technique known in the art. In one embodiment, Fmoc-based SPPS is preferred for assembling linear peptides, which are then cyclized in solution or on the solid phase.

[0077] The ClipPA technology has been used to synthesize a series of novel polymyxin lipopeptide analogs. Synthetic details are described in Examples 1-3.

[0078] As described in Example 4, polymyxin analogs of the invention were screened against E. coli and compared with the known activity spectrum of synthetic polymyxin B3. In Example 5, the nephrotoxicity of selected polymyxin B analogs was measured. Their cytotoxicity was evaluated in Example 6. In Example 7, compounds of the invention were tested against a panel of clinically relevant multidrug-resistant Gram-negative pathogens. In Example 8, phenotypic antimicrobial susceptibility testing was performed against selected compounds using a panel of clinically relevant multidrug-resistant Gram-negative pathogens.

[0079] In summary, more than half of the compounds of the present invention prepared and tested showed antibacterial activity against E. coli with MICs between 1 and 2 μg / mL. Notably, this activity is within the range reported for both clinically used PMB and colistin formulations. Promising activity was also observed against a variety of clinically important pathogens, including carbapenem-resistant Enterobacteriaceae and carbapenem-resistant Acinetobacter baumannii. Dose limitations of polymyxins due to nephrotoxicity are an important factor in the treatment of infectious diseases. We surprisingly found that the compounds of the present invention generally showed little or no toxicity at high doses in the renal organ model.

[0080] Thus, the compounds of the present invention constitute novel antibiotics with highly desirable properties that can be utilized in the treatment of microbial infections.

[0081] 5.3 Pharmaceutical Compositions and Uses of the Compounds of the Invention In another aspect, the present invention relates to a pharmaceutical composition comprising a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof, and a pharma- ceutically acceptable carrier. In one embodiment, the composition is a pharmaceutical composition.

[0082] The term "pharmaceutically acceptable carrier" means a carrier, diluent or excipient that is generally safe, non-toxic, and biologically or otherwise undesirable, that may be administered to a subject, together with a compound of formula (I), and includes carriers suitable for veterinary and human pharmaceutical use.

[0083] Pharmaceutically acceptable carriers, diluents or excipients that can be used in the compositions may include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, self-emulsifying drug delivery systems (SEDDS) such as d-α-tocopherol polyethylene glycol 1000 succinate, drug dosage form surfactants such as Tweens, serum proteins such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinylpyrrolidone, cellulosic substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylic acid esters, waxes, polyethylene polyoxypropylene-block polymers, polyethylene glycol, wool fat. Cyclodextrins such as α-, β-, and γ-cyclodextrin, or chemically modified derivatives such as hydroxyalkylcyclodextrins, including 2- and 3-hydroxypropyl-3-cyclodextrin, or other solubilized derivatives may also be advantageously used to enhance delivery. Oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, or carboxymethylcellulose or similar dispersing agent, which may be commonly used in formulating pharma- ceutically acceptable dosage forms such as emulsions and / or suspensions.

[0084] In one aspect, the present invention provides a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof for treating or preventing a bacterial infection in a subject.

[0085] In one aspect, the present invention relates to a method of treating or preventing a bacterial infection in a subject, comprising administering to the subject a therapeutically effective amount of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof.

[0086] In one aspect, the invention relates to the use of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof in the manufacture of a medicament for the treatment or prevention of a bacterial infection in a subject.

[0087] In one embodiment, the bacterial infection is a gram-negative infection.

[0088] In some embodiments, the Gram-negative bacterial infection may be caused by one or more species selected from one or more genera: Acinetobacter, Actinobacillus, Bartonella, Bordetella, Brucella, Burkholderia, Campylobacter, Cyanobacteria, Enterobacter, Embryonia, Escherichia; Francisella, Helicobacter, Haemophilus, Klebsiella, Legionella; Moraxella, Morganella, Neisseria, Pasteurella, Proteus, Providencia, Pseudomonas, Salmonella, Serratia, Staphylococcus aureus, Stenotrophomonas, Treponema, Vibrio; and Yersinia.

[0089] In certain embodiments, the bacterial infection may be caused by a bacterium selected from the group consisting of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella oxytoca, Stenotrophomonas maltophilia, Enterobacter cloacae, Citrobacter freundii, Escherichia coli, and Salmonella enterica.

[0090] In certain embodiments, the bacterial infection may be caused by a bacterium selected from the group consisting of isolates phenotypically characterized as carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, colistin-resistant Escherichia coli, carbapenem-resistant Acinetobacter baumannii (CRAB) or carbapenem-resistant Pseudomonas aeruginosa (CRPA).

[0091] The use of polymyxin B and colistin (polymyxin E) has been tested and shown to be effective against some multidrug-resistant (MDR) bacterial infections. Currently, these are used as a last line of defense in severe cases, but their usefulness is limited because of observed nephrotoxic side effects.

[0092] Nephrotoxicity is also currently the major dose limiting factor for polycolistin, therefore compounds with improved nephrotoxicity properties would allow for the administration of higher doses to more effectively treat infections and inhibit the development of polycophysin resistance.

[0093] Thus, in one embodiment, the method comprises administering to a subject a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof, wherein the compound has less nephrotoxicity than polymyxin B and / or colistin, for the treatment or prevention of a bacterial infection. Exemplary methods for assessing nephrotoxicity are described herein and can include other methods known to one of skill in the art.

[0094] In further embodiments, the present invention provides methods and compounds for sensitizing Gram-negative bacteria to antimicrobial agents or host defense complements present in serum. As used herein, the term "sensitize" is intended to include any ability to increase susceptibility, increase susceptibility to an antimicrobial agent, or render a bacterium susceptible.

[0095] In the treatment method of the present invention, the pharmaceutical composition of the present invention can be administered as a single dose or multiple dose formulation, or as a sole therapeutic agent, or in combination with one or more additional therapeutic agents, either simultaneously, sequentially, or separately. The one or more additional therapeutic agents depend on the disease or disorder to be treated, or other desired therapeutic benefit. As known to those skilled in the art, the one or more additional therapeutic agents can be used in the therapeutic amount indicated or approved for the particular agent. The pharmaceutical compositions of the present invention are formulated to allow administration to a subject by any selected route, including but not limited to oral or parenteral (including topical, subcutaneous, intramuscular and intravenous) administration. In some embodiments, the compositions are formulated for administration orally, intravenously, subcutaneously, intramuscularly, transdermally, intraperitoneally, or other pharma- ceutically acceptable routes. For example, the compositions can be prepared with a suitable pharma- ceutically acceptable carrier (including excipients, diluents, adjuvants, and combinations thereof) selected according to the expected route of administration and standard pharmaceutical practice. For example, the compositions can be administered orally as powders, liquids, tablets, capsules, or topically as ointments, creams, lotions. Suitable formulations may contain additional agents, including emulsifiers, antioxidants, flavorings, or colorings, as needed, and may be adapted for immediate, delayed, modified, sustained, pulsatile, or controlled release.

[0096] The composition may be administered via a parenteral route.Examples of parenteral dosage forms include aqueous solutions of active agents, isotonic saline or 5% dextrose, or other well-known pharma- ceutically acceptable excipients.For example, cyclodextrin or other solubilizing agents known to those skilled in the art can be used as pharmaceutical excipients to deliver therapeutic agents.

[0097] Examples of dosage forms suitable for oral administration include, but are not limited to, tablets, capsules, tablets or similar forms, or any liquid form that can provide a therapeutically effective amount of the composition, such as syrups, aqueous solutions, emulsions, etc. Capsules may contain any standard pharma-ceutically acceptable material, such as gelatin or cellulose. Tablets can be formulated according to conventional procedures by compressing a mixture of the active ingredient with a solid carrier and a lubricant. Examples of solid carriers include starch and sugar bentonite. The active ingredient may also be administered in the form of a hard-shelled tablet or capsule that contains a binder, such as lactose or mannitol, a conventional filler, and tableting.

[0098] Examples of dosage forms suitable for transdermal administration include, but are not limited to, transdermal patches, transdermal bandages, and the like.

[0099] Examples of dosage forms suitable for topical administration of the composition include any lotion, stick, spray, ointment, paste, cream, gel, etc., whether applied directly to the skin or via an intermediate such as a pad, patch, etc.

[0100] Examples of dosage forms suitable for suppository administration of the composition include any solid dosage form for insertion into a body orifice, particularly dosage forms for insertion into the rectum, vagina and urethra.

[0101] Examples of dosage forms suitable for injection of the compositions include intravenous injection, delivery by bolus, such as single or multiple doses by subcutaneous, subdermal and intramuscular administration or oral administration.

[0102] Examples of dosage forms suitable for depot administration of the composition include pellets or solid forms in which the active agent(s) are entrapped in a matrix of biodegradable polymers, microemulsions, liposomes, or are microencapsulated.

[0103] Examples of infusion devices for the compositions include infusion pumps to provide the desired number of doses or steady state administration, including implantable drug pumps. Examples of implantable infusion devices for the compositions include any solid form in which the active agent(s) is encapsulated within or dispersed throughout a biodegradable or synthetic polymer, such as silicone, silicone rubber, silastic, or similar polymer.

[0104] Examples of dosage forms suitable for transmucosal delivery of the composition include depository solutions for enemas, pessaries, tampons, creams, gels, pastes, foams, spray solutions, powders, and similar formulations that contain the active ingredient plus suitable carriers known in the art. Such dosage forms include forms suitable for inhalation or insufflation of the composition, including compositions that contain solutions and / or suspensions in pharma- ceutically acceptable aqueous or organic solvents, or mixtures and / or powders thereof. Transmucosal administration of the composition may utilize any mucous membrane, but generally utilizes nasal, buccal, vaginal, and rectal tissues. Formulations suitable for nasal administration of the composition can be administered in liquid form, such as nasal sprays, nasal drops, or by aerosol administration with a nebulizer, including aqueous or oily solutions of the polymer particles. The formulations may be prepared as aqueous solutions, such as solutions using saline, benzyl alcohol or other suitable preservatives, absorption enhancers to enhance bioavailability, fluorocarbons, and / or other solubilizing or dispersing agents known in the art.

[0105] Examples of dosage forms suitable for buccal or sublingual administration of the composition include tablets, tablets, etc. Examples of dosage forms suitable for ophthalmic administration of the composition include inserts and / or compositions comprising solutions and / or suspensions in pharma- ceutically acceptable aqueous or organic solvents.

[0106] Examples of formulations of compositions are described in Sweetman, SC (Ed.). Martindale. Complete Pharmaceutical Reference, 33rd Edition, Pharmaceutical Press, Chicago, 2002, 2483 pp.; Aulton, ME (Ed.) Pharmaceutics. The Science of Dosage Form Design. Churchill Livingstone, Edinburgh, 2000, 734 pp.; and Ansel, H. C, Allen, LV and Popovich, NG Pharmaceutical Dosage Forms and Drug Delivery Systems, 7th Edition., Lippincott 1999, 676 pp. Excipients for the manufacture of drug delivery systems are described in various publications known to those skilled in the art, such as Kibbe, EH Handbook of Pharmaceutical Excipients, 3rd Edition, American College of Pharmacology, Washington, 2000, 665 pages. The USP also provides examples of modified release oral dosage forms, including those formulated in tablets or capsules. For example, see United States Pharmacopeia 23 / National Formulary 18, United States Food and Drug Administration Treaty Organization, Rockville MD, 1995 (hereafter "USP"), which also describes specific tests for determining the drug release potential of sustained and delayed release tablets and capsules. USP drug release testing for sustained and delayed release articles is based on drug dissolution of the dosage unit and the elapsed test time. Descriptions of various test equipment and programs are found in the USP. FDA provides further guidelines for the analysis of sustained release dosage forms (see Guidance for Industry: Sustained Release Oral Dosage Forms: Development, Evaluation, and Application of in Vitro / In Vivo Correlations. Rockville, MD: Center for Drug Evaluation and Research, Food and Drug Administration, 1997).

[0107] The dosage forms described herein may be in the form of physically discrete units suitable for use as unitary dosages for the subjects to be treated, each unit containing a predetermined amount of active material calculated to produce a desired therapeutic effect. A dosage unit may contain from about 0.1 to about 2000 mg of each active ingredient.

[0108] The dosage level of the active ingredient in the pharmaceutical composition may be varied to provide an amount of active ingredient, composition, and method of administration that is non-toxic (effective amount) to the patient and effectively achieves the therapeutic effect required for a particular patient. Data obtained from cell culture assays and animal studies can be used to determine appropriate dosage ranges for human subjects.

[0109] The selected dose level will depend on a variety of pharmacokinetic factors, including the activity of the particular composition used, the route of administration, the time of administration, the excretion rate of the particular compound of the invention used, other drugs, compounds and / or materials used in combination with the particular composition used, the age, sex, weight, condition, general health and medical history of the patient being treated, and similar factors known in the medical art. In general, the daily amount or program should be within the range of about 0.01 mg to about 2000 mg of the compound of the invention per kg of body weight.

[0110] In another aspect, the present invention provides a method of killing bacteria comprising contacting the bacteria with a bactericidal amount of a compound of formula (I) or a pharma- ceutically acceptable salt or solvate thereof.

[0111] In the context of this disclosure, "killing" bacteria means that the number of remaining bacteria in a population of bacterial cells exposed to the compounds of the invention described herein is reduced compared to the number of viable bacteria in an untreated population.

[0112] In some embodiments, bacterial "kill" is determined by measuring the reduction in viable bacterial cell count at set time points during culture in the presence of the antimicrobial combination ("kill time curve").

[0113] In another aspect, there is provided a method of inhibiting the growth of at least one bacterial species, comprising contacting said bacterial species with a bacteriostatic amount of a compound of formula (I), or a pharma- ceutically acceptable salt or solvate thereof.

[0114] In the context of this disclosure, "inhibiting the growth" of at least one bacterial species means that under conditions that stimulate bacterial growth (in the absence of the antibacterial combination), there is no detectable increase in the number of bacteria present and / or the duration of bacterial presence or infection.

[0115] In some embodiments, the "inhibited growth" of at least one bacterial species is greater than or equal to 600 nm In some embodiments, inhibition is observed when the optical density of the treated culture is less than 10% of the optical density of the control culture.

[0116] In the above aspects, in one embodiment the bacterium is a gram-negative bacterium.

[0117] 6. Working Example General methods and materials All reagents are purchased as reagent grade and used without further purification. Solvents used in reactions are distilled according to standard procedures prior to use.

[0118] The above general methods and methods apply to all of the following examples unless alternative general methods and methods are indicated.

[0119] Example 1: Synthesis of building blocks for preparing polymyxin B analogues Lipidated amino acid building blocks were prepared by the mercaptan-ene reaction of cysteine ​​with vinyl esters (ClipPA) to give S-lipidated Nα-Fmoc amino acids. The use of this reaction to prepare lipidated cysteine ​​residues for incorporation into Fmoc SPPS has been previously described in Yang et al., 2016 and Wright, et al., 2013.

[0120] Using this method, six diverse lipidated cysteines were prepared incorporating short- or medium-chain lipids (3a-3c), branched lipids (3d), and aromatic lipids (3e and 3f) (Scheme 1).

[0121] [ka] Scheme 1

[0122] All compounds were obtained in moderate (41%) to excellent (95%) yields and were efficiently purified by standard silica gel rapid chromatography to provide large amounts of Fmoc-protected S-lipidated cysteines ready for incorporation into SPPS.

[0123] (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino-3-((2-(propionyloxy)ethyl)thio)propanoic acid (3a): [α] [ka] + 14.8 (c 0.014, CHCl3); 1 H NMR (400 MHz, CDCl3): δ H= 1.12 (t, J = 7.2, 3H, CH3, H-1), 2.32 (q, J = 7.6, 2H, CH2, H-2), 2.78 (t, J = 6.4 Hz, 2H, CH2, H-6), 3.04-3.17 (m, 2H, CH2, H-8), 4.23 (t, J = 6.8 Hz, 2H, CH2, H-5), 4.42 (d, J = 6.8 Hz, 2H, CH2, H-13), 4.65 (d, J = 6.8 Hz, 1H, CH, H-14), 5.74 (d, J = 1.8 Hz, 1H, CH, H-9), 7.31 (t, J = 7.2 Hz, 2H, 2 × CH, H-17 + H-24), 7.39 (t, J = 7.6 Hz, 2H, 2 × CH, H-18 + H-23), 7.60 (d, J = 7.6 Hz, 2H, 2 × CH, H-16 + H-25), 7.75 (d, J = 7.6 Hz, 2H, 2 × CH, H-19 + H-22)。 13 C NMR (100 MHz, CDCl3): δ C = 9.0 (CH3, C-1), 27.4 (CH2, C-2), 31.2 (CH2, C-6), 34.4 (CH2, C-8), 47.1 (CH, C-14), 53.6 (CH, C-9), 63.2 (CH2, C-5), 67.4 (CH2, C-13), 120.0 (2 × CH, C-17 + C-24), 127.1 (2 × CH, C-18 + C-23), 127.8 (2 × CH, C-19 + C-22), 141.3 (2 × C , C-20 + C-21), 143.6 (C, C-15), 143.7 (C, C-26), 156.0 (C=O, C-11), 174.6 (C=O, C-3), not observed (C=O, C-27)。HRMS-ESI: m / z [M + Na] + calcd fまたは[C 23 H 25 NO6S + Na] + 466.1295 ; found 466.1297.

[0124] (R)-2-((((9H-フルオレン-9-イル)メトキシ)カルボニル) Amin-3-((2-(ブチリルオキシ)エチル)チオ)プロパン acid (3b): [α]

change

[0125] (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino-3-((2-(undecanoyloxy)ethyl)thio)propanoic acid (3c): 1 H NMR (400 MHz, CDCl3): δ H= 0.87 (t, J = 6.4 Hz, 4H, CH3+ CH of CH2, H-1 + H-2), 0.93 (t, J = 7.2 Hz, 1H, CH of CH2, H-2), 1.24 (s, 10H, 5 × CH2, H-4 + H-5 + H-6 + H-7 + H-8), 1.58-1.64 (m, 2H, CH2, H-3), 2.29 (t, J = 7.2 Hz, 2H, CH2, H-9), 2.78 (t, J = 6.0, 2H, CH2, H-13), 3.04-3.16 (m, 2H, CH2, H-15), 4.22 (q, J = 6.9 Hz, 2H, CH2, H-12), 4.42 (d, J = 6.8 Hz, 2H, CH2, H-20), 4.66 (d, J = 6.4 Hz, 1H, CH, H-21), 5.54 (BrS, 1H, NH), 5.71 (d, J = 7.2 Hz, 1H, CH, H-16), 7.31 (t, J = 7.6, 2H, 2 × CH, H-24 + H-31), 7.40 (t, J = 7.6, 2H, 2 × CH, H-25 + H-30), 7.60 (d, J = 6.8 Hz, 2H, 2 × CH, H-23 + H-32), 7.76 (d, J = 7.2 Hz, 2H, 2 × CH, H-26 + H-29)。 13 C NMR (100 MHz, CDCl3): δ C= 14.1 (CH3, C-1), 18.3 (CH2, C-2), 22.6 (CH2, C-13), 24.9 (CH2, C-15), 29.1 (CH2, C-3), 29.2 (CH2, C-4), 29.4 (CH2, C-5), 31.2 (CH2, C-6), 31.8 (CH2, C-7), 34.2 (CH2, C-8), 34.4 (CH2, C-9), 47.1 (CH, C-21), 53.5 (CH, C-16), 63.1 (CH2, C-12), 67.4 (CH2, C-20), 120.0 (2 × CH, C-23 + C-32), 125.1 (2 × CH, C-24 + C-31), 127.1 (2 × CH, C-25 + C-30), 127.8 (2 × Ch, C-26 + C-29), 141.3 (2 × C, C-27 + C-28), 143.6 (2 × C, C-22 + C-33), 155.9 (C=O, C-18), 161.6 (C=O, C-34), 174.1 (C=O, C-10). HRMS-ESI: m / z [M + Na] + calcd f or [C 30 H 39 NO6S + Na] + 564.2390; found 564.2381

[0126] (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino-3-((2-(pivaloyloxy)ethyl)thio)propanoic acid (3d): [α] [ka] + 6.4 (c 0.02, CHCl3); 1 H NMR (400 MHz, CDCl3): δ H= 1.19 (s, 9H, 3 × CH3, t-Bu), 2.78 (d, J = 2.8 Hz, 2H, CH2, H-6), 3.04-3.16 (m, 2H, CH2, H-8), 4.12 (q, J = 7.2 Hz, 1H, CH of CH2, H-5), 4.22 (q, J = 7.2 Hz, 1H, CH of CH2, H-5), 4.41 (d, J = 6.8 Hz, 2H, CH2, H-13), 4.65 (d, J = 6.0 Hz, 1H, CH, H-14), 5.76 (d, J = 7.6 Hz, 1H, CH, H-9), 7.31 (t, J = 7.2 Hz, 2H, 2 × CH, H-17 + H-24), 7.39 (t, J = 7.6 Hz, 2H, 2 × CH, H-18 + H-23), 7.60 (d, J = 6.4 Hz, 2H, 2 × CH, H-16 + H-25), 7.75 (d, J = 7.6 Hz, 2H, 2 × CH, H-19 + H-22)。 13 C NMR (100 MHz, CDCl3): δ C = 27.1 (3 × CH3, t-Bu), 31.3 (CH2, C-6), 34.4 (CH2, C-8), 38.8 (C, C-2), 47.0 (CH, C-14), 53.6 (CH, C-9), 63.1 (CH2, C-5), 67.4 (CH2, C-13), 120.0 (2 × CH, C-16 + C-22), 125.0 (CH, C-17), 125.1 (CH, C-24), 127.1 (2 × CH, C-19 + C-22), 127.7 (2 × CH, C-18 + C-23), 141.3 (2 × C, C-30 + C-31), 143.6 (C, C-15), 143.7 (C, C-26), 155.9 (C=O, C-11), 174.2 (C=O, C-3), 178.6 (C=O, C-27)。HRMS-ESI: m / z [M + Na] + calcd. fまたは[C 31 H 33 NO6S + Na]+ 494.1608 ; found 494.1596.

[0127] (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino-3-((2-(benzoyloxy)ethyl)thio)propanoic acid (3e): [α] [ka] + 9.7 (c 0.01, CHCl3); 1 H NMR (400 MHz, CDCl3): δ H = 2.92 (d, J = 4.4 Hz, 2H, CH2, H-10), 3.09-3.21 (m, 2H, CH2, H-12), 4.22 (t, J = 6.8 Hz, 1H, CH of CH2, H-9), 4.40-4.69 (m, 3H, CH of CH2+ CH2, H-9 + H-17), 4.68 (t, J = 4.8, 1H, CH, H-18), 5.23 (BrS, 1H, NH), 5.74 (d, J = 7.2, 1H, CH, H-13), 7.29 (t, J = 7.2 Hz, 2H, 2 × CH, H-22 + H-27), 7.38 (t, J = 7.2 Hz, 2 × CH, H-21 + H-28), 7.41 (t, J = 7.6 Hz, 2H, 2 × CH, H-4 + H-2), 7.54 (t, J = 7.6 Hz, 1H, H-3), 7.59 (d, J = 6.8 Hz, 2H, 2 × CH, H-20 + H-29), 7.74 (d, J = 7.6 Hz, 2H, 2 × H, H-23 + H-26), 8.02 (d, J = 7.2 Hz, 2H, 2 × H, H-1 + H-5). 13 C NMR (100 MHz, CDCl3): δ C= 31.3 (CH2, C-10), 34.5 (CH2, C-12), 47.1 (CH, C-18), 53.6 (CH, C-13), 63.7 (CH2, C-9), 67.3 (CH2, C-17), 111.0 (2 × CH, C-20 + C-29), 125.1 (C, C-6), 127.1 (2 × CH, C-23 + C-26), 127.7 (2 × CH, C-22 + C-27), 128.4 (2 × CH, C-4 + C-2), 129.7 (2 × CH, C-1 + C-5), 133.2 (CH, C-3), 141.3 (2 × C, C-24 + C-25), 143.6 (2 × C, C-19 + C-30), 155.9 (C=O, C-15), 171.3 (C=O, C-7), 173.7 (C=O, C-31). HRMS-ESI: m / z [M + Na] + calcd f or [C 27 H 25 NO6S + Na] + 514.1295 ; found 514.1283.

[0128] (R)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino-3-((2-((4-(tert-butyl)benzoyl)oxy)ethyl)thio)propanoic acid (3f): [α] [ka] + 12.4 (c 0.017, CHCl3); 1 H NMR (400 MHz, CDCl3): δ H= 1.31 (s, 9H, 3 × CH3, t-Bu), 2.91 (d, J = 5.6 Hz, 2H, CH2, H-10), 3.16 (dd, J = 3.6, 15.6 Hz, 2H, CH2, H-12), 4.22 (t, J = 6.8 Hz, 1H, CH of CH2, H-9), 4.41-4.47 (m, 3H, CH of CH2+CH2, H-9 + H-17), 4.68 (d, J = 6.4 Hz, 1H, CH, H-18), 5.76 (d, J = 7.6 Hz, 1H, CH, H-13), 7.34 (t, J = 7.2 Hz, 2H, 2 × CH, H-21 + H-28), 7.38 (t, J = 7.2 Hz, 2H, 2 × CH, H-22 + H-27), 7.42 (d, J = 8.4 Hz, 2H, 2 × CH, H-4 + H-2), 7.59 (d, J = 7.6 Hz, 2H, 2 × CH, H-20 + H-29), 7.74 (d, J = 7.6 Hz, 2H, 2 × CH, H-23 + H-26), 7.94 (d, J = 8.4 Hz, 2H, 2 × CH, H-1 + H-5)。 13 C NMR (100 MHz, CDCl3): δ C= 31.0 (3 × CH3, t-Bu), 31.3 (CH2, C-10), 34.5 (C, C-32), 35.0 (CH2, C-12), 47.1 (CH, C-18), 53.6 (CH, C-13), 63.6 (CH2, C-9), 67.3 (CH2, C-17), 119.9 (2 × CH, C-20 + C-29), 125.1 (2 × CH, C-21 + C-28), 125.1 (C, C-6), 125.4 (2 × CH, C-23 + C-26), 127.0 (2 × CH, C-22 + C-27), 127.1 (2 × CH, C-2 + C-4), 129.5 (2 × CH, C-1 + C-5), 141.2 (2 × C, C-24 + C-25), 143.7 (2 × C, C-19 + C-30), 156.8 (C=O, C-15), 166.5 (C=O, C-7), 171.3 (C=O, C-31). HRMS-ESI: m / z [M + Na] + calcd f or [C 31 H 33 NO6S + Na] + 570.1921 ; found 570.1917. Example 2: Synthesis of mono-S-lipidated polymyxins and bis-S-lipidated polymyxins (23-60)

[0129] The synthesis of compounds (23–60) is based on the synthesis of polymyxin and E2 (Xu et al., 2015), and a variant of this synthesis is shown in Figure 1. The synthesis started with the functionalization of 2-chlorotriyl chloride ChemMatrix resin with Fmoc-Dab-O-allyl via side-chain anchoring of the amino group to give 4 at a loading of 0.3 mmol / g. Fmoc amino acids were then introduced by standard Fmoc SPPS cycles using 20% ​​piperidine in DMF for Fmoc removal (2 × 5 min). Coupling of the incoming Fmoc amino acids with lipidated building blocks was carried out with HATU / DIPEA for 20 min (Figure 1). This provided the resin-bound peptides 5a / 5b, which were coupled with S-lipidated building modules (3a–3f) to give 6. The N-terminal Fmoc protecting group was then replaced by a Boc group to avoid potential side reactions during removal of the Dde group from Lys-4 / Dab-4 with hydrazine, the Fmoc group being unstable towards these conditions. Lys-4 / Dab-4 on the linear resin-bound peptide was acylated with Fmoc-Thr(tBu)-OH to give 7, and the allyl ester on Dab-9 was removed with Pd(PPh3)4 in the presence of PhSiH3 to give 8.

[0130] The Fmoc group on Thr-10 was removed by standard Fmoc deblocking conditions and the cyclic peptide was obtained by on-resin macrocyclization using PyBOP and HOAt, easily monitored by the Kaiser test for the absence of free amines. Finally, the free cyclic peptide was released from the resin with simultaneous removal of global side chain protecting groups. The cyclic lipopeptides were recovered, purified by HPLC and their structures confirmed by LC-MS. Yields of the final products ranged from 1.1% to 26% relative to the initial resin loading, with several mg often obtained.

[0131] For the bis-lipidated compounds (35–42 and 49–57), a similar method was used as shown in Figure 1, except that Fmoc-Leu-OH or Fmoc-D-Phe-OH was replaced by the appropriate lipidated Fmoc-Cys building blocks 3a to 3f or their Fmoc-D-Cys lipidated counterparts. According to Example 1, Fmoc-D-Cys-OH was used to prepare Fmoc-D-Cys lipidated building blocks and characterized by conventional spectroscopic methods. For the bis-lipidated compounds (43–48), a procedure employing an orthogonal protection strategy was employed (Figure 2). Fmoc-Cys(Trt)-OH (Trt = triphenylmethyl) was used instead of the N-terminal S-lipidated building block and Fmoc-Cys(Acm)-OH (Acm = acetamidomethyl) was used instead of Leu-7, resulting in resin-bound 9. Substitution of the N-terminal Fmoc group with Boc, removal of the Dde protecting group on Dab4, and acylation with Fmoc-Thr(tBu) gave 10. Removal of Fmoc from Thr-10 and allyl from Dab-9, followed by resin cyclization and resin cleavage, gave 12. S-lipidation of the N-terminal cysteine ​​using standard ClipPA reaction conditions gave monolipidated polycophysin 12. Removal of the Acm group on Cys-7 with Ag(OAc) revealed the free mercaptan, which was S-lipidated to produce bislipidated polymyxins (43–48). Other thiol shanks that can be incorporated in place of Cys include those derived from L- and D-Cys, such as 3-mercapto-D-valine (penicillamine).

[0132] Containing different thiol handles at the N-terminus and / or exocyclic region ( 1 -Thr 2 -Dab 3For monolipidated polymyxins (58-60) with different amino acids present at the L-terminal end, it is more convenient to prepare the usual intermediate 16 as shown in Figure 3, incorporate the desired exocyclic amino acid, incorporate an N-terminal thiol-containing amino acid or a mercapto acid, and then S-lipidate in solution (Figure 3). Other thiol handles that can be incorporated instead of Cys include those derived from L- and D-Cys, such as 3-mercapto-D-valine (penicillamine).

[0133] Table 1. Structures of polymyxin B S-lipopeptides [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5]

[0134] In Table 1, MPA=2-mercaptoacetyl, h-Cys=high-L-Cys. In Table 1, the group "Z" refers to the α-carbon atom to which the carboxyl bound to Dab1 and the side chain (shown in formula (II)) are attached. Here, Z is "Cys" in formula (II), A is A1 in formula (I) and n=1. In formula (II), the amine group of Cys is J. Here, Z is MPA in formula (II), and A is A2 in formula (I). Here, Z is h-Cys in formula (II), A is A2 in formula (I) and n=1 in formula (I). In other words, A in formula (I) is In equation (2), [ka] is equivalent to.

[0135] Table 2. Mass spectrometry data of S-lipidated polycophysin [Table 2-1] [Table 2-2] Example 3: Synthesis of monolipidated polymyxin nonapeptides (61-104)

[0136] Polymyxin nonapeptides are truncated forms of polymyxin B that lack the Dab-1 amino acid. They contain different thiol handles at the N-terminus and / or exocyclic regions (Dab 1 -Thr 2 -Dab 3 For compounds (61-64 and 81-88) in which different amino acids are present in the 2-amino acid residue, it is more convenient to prepare a common intermediate 16 as shown in Figure 3 for the synthesis of the above polymucophycins.

[0137] For the synthesis of S-lipidated analogs of polymyxin B, a modified chemoenzymatic method as reported by Danner et al. was used (Figure 4). Briefly, commercially available polymyxin B sulfate was enzymatically delipidated by papain to give intermediate 20, which was Boc protected at the remaining Dab residues while leaving the N-terminal threonine unaffected (compound 21). A cysteinyl thiol handle was introduced at the N-terminus of the peptide using a thiazolidine derivative of L-Cys or D-Cys. This reduced potential racemization during introduction. Boc deprotected polymyxin B nonapeptides 22a / b, which were then subjected to a ClipPA reaction, which directly produced S-lipidated polymyxin B nonapeptides containing the L- or D-Cys handle (65–80, 89–104).

[0138] Table 3. Structures of polymyxin BS lipidated nonapeptides. [Table 3-1] [Table 3-2] [Table 3-3] [Table 3-4]

[0139] In Table 3, MPA=2-mercaptoacetyl, h-Cys=high-L-Cys. In Table 3, the group "Z" refers to the α-carbon atom to which the carboxyl bound to Dab1 and the side chain (shown in formula (III)) are bound. Here, Z is "Cys" in formula (III), A is A1 in formula (I) and n=1. The amine group of Cys is represented by J in formula (III). Here, Z is MPA in formula (III) and A is A2 in formula (I). Here, Z is h-Cys in formula (III), A is A2 in formula (I) and n=1. In other words, A in formula (I) is In equation (3), [ka] is equivalent to.

[0140] Table 4. Mass spectrometry data of S-lipidated polymyxin nonapeptides. [Table 4-1] [Table 4-2] [Table 4-3] Example 4: Antibacterial testing of compounds of the present invention

[0141] All 81 compounds prepared in Examples 2 and 3 were screened against a set of Gram-negative bacteria to assess their ability to inhibit bacterial growth. The data is shown in Table 5. Median values ​​are shown.

[0142] In general, many of the S-lipidated polymyxin analogs were found to maintain excellent activity against E. coli, exhibiting potency equivalent to polymyxin B3 (0.25 μg / ml) or within one twofold dilution. Extension of the polymyxin macrocycle by replacing Lys (23–28) with Dab (29–34)) offered little advantage in antibacterial activity, but was generally well tolerated, although detrimental to Acinetobacter baumannii and Pseudomonas aeruginosa. S-lipidation with short alkyl chains or aromatic groups provided the most potent analogs against most species (26–29, 32–34, 38–40 and 43–48), with 33, 34, and 47, all containing aromatic lipids, being more potent and outperforming polymyxin against colistin-resistant E. coli ATCC MS8345.

[0143] Analogs designed with S-lipidated cysteine ​​building blocks at the N-terminus alone or at the N-terminus and positions 6 or 7 all provide efficient analogs, although position 6 appears to be less tolerant to certain modifications (53-57). Taking an effective bisS-lipidated analog 39 (0.5 μg / ml, E. coli), we introduced acylation at the N-terminus (49-52) and demonstrated favorable changes to the propionyl lipid of the cysteine ​​handle (58-60) to provide 59 and 60.

[0144] Among polymyxin nonapeptide analogs (61–104), a clear preference for D-Cys at the N-terminus was observed, as compounds containing L-Cys (65–73) were largely inactive. (74–80) Using alternative nonapeptide scaffolds containing Dap (81–84) or D-Ser (85–88) at position 3 with different thiol handles and propionate lipids, the D-Cys homologs (82 and 86) were most active against E. coli.

[0145] Using the PMB nonapeptide with D-Cys at the N-terminus, various S-alkyl lipids were examined. (89-103) Most retained good activity against E. coli, P. aeruginosa, and K. pneumoniae, but were less potent against Acinetobacter baumannii and E. coli ATCC MS8345.

[0146] Table 5. MICs (μg / mL) of S-lipidated polymyxins and S-lipidated polymyxin nonapeptides. [Table 5-1] [Table 5-2] [Table 5-3] [Table 5-4] [Table 5-5] [Table 5-6] Example 5: Nephrotoxicity of selected ClipPA polymyxins

[0147] Polymyxin-induced nephrotoxicity remains a major dose-limiting factor that can occur in up to 60% of patients. Mechanistically, polymyxins accumulate in renal tubules and induce apoptosis via mitochondrial damage, endoplasmic reticulum stress, oxidative stress, and cell cycle arrest (Azad et al., 2019).

[0148] Human induced pluripotent stem cell-derived renal organoids were used to evaluate the cytotoxicity of selected polymyxin analogues in physiologically relevant human renal tissue (Soo et al. 2018). Mono-lipidated analogues 29, 31, 33 containing propyl, decyl or phenyl lipids, bis-lipidated compounds 35, 38, 39 containing propyl, tert-butyl or phenyl lipids, respectively, and N-capped bis-lipidated (phenyl) 49 were selected.

[0149] The control compound polymyxin B and seven ClipPA analogs were tested by adding a range of concentrations (based on Gallado-Godoy et al. 2016) to the organoids on day 12 of the protocol, corresponding to the optimal maturity of the organoid tissue, as previously described. As a positive control, organoids were treated with 100 μM cisplatin, a chemotherapy drug with severe nephrotoxic side effects in patients and kidney organoids (Table 6).

[0150] Table 6. Summary of nephrotoxicity of polymyxin B and novel analogues on renal organoids [Table 6-1] [Table 6-2] nd=indetermined score: 1=no effect, 2=mild deterioration, 3=severe deterioration, 4=complete deterioration. -ve control: water=1, +ve control 100 μM cisplatin=3 After 48 hours, toxicity was scored for signs of renal tubule degradation visible in brightfield images (not shown). The present assay revealed dose-dependent degradation following treatment with polymyxin B and compounds 31, 33, 38-49, 91-104, whereas organoids treated with compounds 29, 35, 58-60, 82-83 and 86 showed virtually no tissue damage up to 1 mm.

[0151] To obtain a quantitative readout of apoptosis, we measured TUNEL+ cells on paraffin sections of compound-treated organoids. We observed a similar trend as seen in brightfield imaging: a significantly lower percentage of apoptotic cells in organoids treated with compounds 29 and 35 compared to polymyxin B (Figure 5).

[0152] Example 7: Cytotoxicity studies with ClipPA polymucophysin To assess whether ClipPA modification introduced new toxicity, inhibitory concentrations were measured against Vero and HaCaT cell lines. Compound 29, which contains a propionyl lipid, is approximately 2.5-fold less toxic to the Vero cell line than either commensin or polycomensin B (Figure 6 and Table 7), and has a comparable inhibitory effect against the HaCaT cell line. Standard errors of each measurement are shown.

[0153] Table 7. IC of compounds in Vero or HaCaT cell lines 50 Calculated value of [Table 7]

[0154] Compound 39, which has a phenyl lipid at the N-terminus and Leu-7, is approximately 5-fold more toxic to both cell lines compared to compound 29. This is similar to the nephrotoxicity results, where 29 was significantly less toxic. Large amounts of compound 29 are still required to cause an inhibitory effect (>500 μg / mL), indicating low toxicity of the polymyxins tested in both cell lines. Example 8: Phenotypic antimicrobial susceptibility testing for multidrug-resistant pathogens

[0155] Given the promising antibacterial activity and low toxicity associated with compounds 29, 35, and 38, these compounds underwent the next round of phenotypic antibacterial susceptibility testing using a set of clinically relevant multidrug-resistant Gram-negative pathogens. This panel included isolates phenotypically characterized as carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, colistin-resistant Escherichia coli, carbapenem-resistant Acinetobacter baumannii (CRAB) or carbapenem-resistant Pseudomonas aeruginosa (CRPA). These isolates were selected because each is resistant to multiple different antibiotic families in clinical use, resulting in limited but important treatment options, and each of these pathogen types is recognized as "Priority 1: Urgent" on the World Health Organization (WHO) list of priority pathogens for new antibiotic research and development. Therefore, antibacterial activity against any of these pathogens would be considered clinically important. Encouragingly, each compound showed promising antibacterial activity against members of this test panel, with the exception of CRPA and colistin-resistant E. coli, which were resistant to all three test compounds and the polymyxin B control (Table 8). However, it was noted that many of the compounds tested in Example 4 showed good activity against colistin-resistant E. coli.

[0156] Table 8. MICs of compounds 29, 35, and 38 against clinically relevant multidrug-resistant pathogen types. [Table 8] ESBL=extended-spectrum β-lactamase producing, CRE=carbapenem-resistant Enterobacteriaceae, CR=colistin-resistant, CRPA=carbapenem-resistant Pseudomonas aeruginosa, CRAB=carbapenem-resistant Acinetobacter baumannii.

[0157] Three biological tests revealed that the minimum inhibitory concentrations of each compound against each pathogen were within the range of 2-8 mg / L. In almost all cases, the MICs observed were within a two-fold dilution range of the MICs observed with the polymyxin B control, clearly demonstrating an antimicrobial activity profile similar to that of polymyxin B for each of the three test compounds. 8.Reference materials

[0158] Brown, P., & Dawson, MJ (2017). Development of novel polymyxin derivatives for multidrug-resistant Gram-negative infections. JAntibiot (Tokyo), 70(4), 386-394. Danner, RL, Joiner, KA, Rubin, M., Patterson, WH, Johnson, N., Ayers, KM, & Parrillo, JE (1989). Purification, toxicity, and antiendotoxin activity of polymyxin B nonapeptide. Antimicrob. Agents Chemother., 33(9), 1428-1434. Gallardo-Godoy, A.; Muldoon, C.; Becker, B.; Elliott A.G; Lash L.H; Huang J.X. (2016). Activity and predicted nephrotoxicity of synthetic antibiotics based on polymyxin B. J Med Chem. 59:1068-1077. Magrone, P., Cavallo, F., Panzeri, W., Passarella, D., & Riva, S. (2010). Exploiting enzyme regioselectivity: a simple methodology for the synthesis of polyhydroxylated hybrid compounds. Org. Biomol. Chem., 8, 5583-5590. Rabanal, F., & Cajal, Y. (2017). Recent advances and perspectives in polymyxin design and development. Nat. Prod. Rep., 34(7), 886-908. Soo, JY; Jansen, J.; Masereuw, R.; Little, M. (2018) Advances in predictive in vitro models of drug-induced nephrotoxicity. NatRevNephrol. 14, 378-393. Velkov, T., Roberts, K. D., Nation, R. L., Thompson, P. E., & Li, J. (2013). Polymyxin pharmacology: new insights into an "old" class of antibiotics. Future Microbiol, 8(6), 711-724. Velkov, T., Thompson, PE, Nation, RL, & Li, J. (2010). Structure-activity relationships of polymyxin antibiotics. J.Med.Chem., 53(5), 1898-1916. Wright, TH, Brooks, AE, Didsbury, AJ, Williams, GM, Harris, PW, Dunbar, PR, & Brimble, MA (2013). Rapid synthesis and evaluation of self-adjuvanting vaccine candidates by direct lipidation of peptides via thiol-ene coupling. Angewandte Chemie-Internationale, 52(40), 10616-10619. Xu, W.-L., Cui, A.L., Hu, X.-X., You, X.-F., Li, Z.-R., & Zheng, J.-S. (2015). A new strategy for the total solid-phase synthesis of polymyxins. Tetrahedron Lett., 56(33), 4796-4799. Yang, SH, Harris, PW, Williams, GM, & Brimble, MA (2016). Lipidation of cysteine ​​or cysteine-containing peptides using the thiol-ene reaction (CLipPA). Eur. J. Org. Chem., (15), 2608-2616.

Claims

1. A compound of formula (I) or a pharmaceutically acceptable salt or solvate thereof: 【Chemical 1】 (however, A is, 【Chemistry 2】 【Chemistry 3】 and 【Chemistry 4】 is selected from Here, R １ is H or —C(O)—(C １ ~C １０ ) alkyl, n is 1 or 2, and R ５ is H or CH ３ and X １ is absent or is Dab, X ２ is Thr, X ３ is selected from the group consisting of Dab, Dap, or D-Ser; X ４ is selected from the group consisting of Dab, Lys, Orn, or Dap; X ６ is D-Phe or 【Chemistry 5】 and X ７ is Leu, or 【Chemistry 6】 and Here, R ２ , R ３ , and R ４ are independently -(C ２ ~C １０ ) alkyl, -(C ３ ~C １０ ) cycloalkyl, aryl, aryl (C １ ~C １０ ) alkyl, -(C １ ~C １０ ) alkylaryl, pyridinyl (C １ ~C １０ ) alkyl, and —(C １ ~C １０ ) alkylpyridinyl; Here, -(C ３ ~C １０ ) cycloalkyl, aryl, and pyridinyl are each independently selected from halo, —(C １ ~C ６ ) alkyl, -(C ３ ~C ６ ) cycloalkyl, —O—(C １ ~C ６ ) alkyl, —O—(C ３ ~C ６ ) cycloalkyl, —S(C １ ~C ６ ) alkyl, —S(C ３ ~C ６ ) cycloalkyl, —NH(C １ ~C ６ ) alkyl, or NH(C ３ ~C ６ ) optionally substituted with cycloalkyl; R ６ and R ７ are independently H or CH ３ is selected from

2. The A is 【Chemistry 7】 (where n is 1 and X １ is Dab and R ２ is as defined in claim 1.

3. 2. The compound of claim 1, wherein A is: 【Chemistry 8】

4. The n is 1, and the X １ does not exist, and the R ２ The compound of claim 3, wherein is as defined in claim 1.

5. A is A2, n is 1, and R ２ The compound of claim 1, wherein

6. 2. The compound of claim 1, wherein A is: 【Chemistry 9】

7. R １ The compound according to any one of claims 1 to 6, wherein is H.

8. The R ２ Ha-(C ２ ~C １０ ) alkyl, -(C ３ ~C １０ ) cycloalkyl, aryl, aryl (C １ ~C １０ ) alkyl, and —(C １ ~C １０ ) alkylaryl, preferably —(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ 7. The compound of claim 1, wherein the aryl group is selected from the group consisting of aryl, ...

9. The X ３ The compound according to any one of claims 1 to 6, wherein is Dab.

10. The X ４ The compound according to any one of claims 1 to 6, wherein is Lys or Dab.

11. The X ６ The compound according to any one of claims 1 to 6, wherein is D-Phe.

12. The X ７ The compound according to any one of claims 1 to 6, wherein is Leu.

13. A is A1, n is 1, and R ２ is -(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ ) alkyl, wherein R １ is H or —C(O)—(C １ ~C １０ ) alkyl, and said X １ is Dab, and said X ２ is Thr, and said X ３ is Dab and X ４ is Dab or Lys, and ６ is D-Phe or 【Chemistry 10】 where R ３ is -(C ２ ~C １０ ) alkyl, -(C ３ ~C １０ ) cycloalkyl, aryl, aryl (C １ ~C １０ ) alkyl, and —(C １ ~C １０ ) alkylaryl, preferably —(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ ) alkyl, and said X ７ is Leu or 【Chemistry 11】 where R ４ is -(C ２ ~C １０ ) alkyl, -(C ３ ~C １０ ) cycloalkyl, aryl, aryl (C １ ~C １０ ) alkyl, and —(C １ ~C １０ ) alkylaryl, preferably —(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ 2. The compound of claim 1, wherein the alkyl is selected from the group consisting of:

14. A is A1, n is 1, and R ２ is -(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ ) alkyl, wherein R １ is H, and the X １ does not exist, and the X ３ is Dab, Dap or D-Ser, and ４ is Dab, and said X ６ is D-Phe, and the X ７ The compound of claim 1 , wherein is Leu.

15. A is A2, n is 1, and R ２ is -(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ ) alkyl, wherein R １ is H, and the X １ is Dab, and said X ３ is Dab, and said X ４ is Dab or Lys, and ６ is D-Phe, and the X ７ The compound of claim 1 , wherein is Leu.

16. A is A1, n is 2, and R ２ is -(C ２ ~C １０ ) alkyl, aryl, and aryl (C １ ~C １０ ) alkyl, wherein R １ is H, and the X １ is Dab, and said X ３ is Dab, and said X ４ is Dab or Lys, and ６ is D-Phe, and the X ７ The compound of claim 1 , wherein is Leu.

17. 2. The compound of claim 1, wherein the compound is selected from the group consisting of polymyxin analogs defined in Table 1 or Table 3.

18. A compound of formula (I), or a pharmaceutically acceptable salt or solvate thereof, selected from the group consisting of compounds 29, 44, 59, 60, 76 and 79. 【Chemistry 12】

19. 10. A pharmaceutical composition comprising the compound of claim 1, or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutically acceptable carrier.

20. A pharmaceutical composition for treating or preventing a bacterial infection, said pharmaceutical composition comprising a therapeutically effective amount of a compound described in claim 1 or a pharmaceutically acceptable salt or solvate thereof.

21. 10. A method of killing bacteria, comprising contacting the bacteria with a bactericidal amount of a compound of claim 1 or a pharmaceutically acceptable salt or solvate thereof.

22. 10. A method for inhibiting the growth of at least one bacterial species, comprising contacting said bacterial species with a bacteriostatic amount of a compound of claim 1 or a pharmaceutically acceptable salt or solvate thereof.

23. 21. The pharmaceutical composition of claim 20, wherein the bacterium is a gram-negative bacterium.

24. The method described in claim 21 or 22, wherein the bacterium is a gram-negative bacterium.

25. The pharmaceutical composition of claim 23, wherein the Gram-negative bacteria comprises one or more species selected from one or more genera of Acinetobacter, Actinobacillus, Bartonella, Bordetella, Brucella, Burkholderia, Campylobacter, Cyanobacteria, Enterobacter, Embinia, Escherichia, Francisella, Helicobacter, Haemophilus, Klebsiella, Legionella, Moraxella, Morganella, Neisseria, Pasteurella, Proteus, Providencia, Pseudomonas, Salmonella, Serratia, Staphylococcus aureus, Stenotrophomonas, Treponema, Vibrio, and Yersinia.

26. 25. The method of claim 24, wherein the Gram-negative bacteria comprise one or more species selected from one or more genera of Acinetobacter, Actinobacillus, Bartonella, Bordetella, Brucella, Burkholderia, Campylobacter, Cyanobacteria, Enterobacter, Embrynia, Escherichia, Francisella, Helicobacter, Haemophilus, Klebsiella, Legionella, Moraxella, Morganella, Neisseria, Pasteurella, Proteus, Providencia, Pseudomonas, Salmonella, Serratia, Staphylococcus aureus, Stenotrophomonas, Treponema, Vibrio, and Yersinia.

27. The pharmaceutical composition of claim 20, wherein the bacteria is selected from the group consisting of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella oxytoca, Stenotrophomonas maltophilia, Enterobacter cloacae, Citrobacter freundii, Escherichia coli, and Salmonella enterica.

28. 23. The method of claim 21 or 22, wherein the bacterium is selected from the group consisting of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Klebsiella oxytoca, Stenotrophomonas maltophilia, Enterobacter cloacae, Citrobacter freundii, Escherichia coli, and Salmonella enterica.

29. The pharmaceutical composition of claim 20, wherein the bacteria is selected from the group consisting of isolates phenotypically characterized as carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, colistin-resistant Escherichia coli, carbapenem-resistant Acinetobacter baumannii (CRAB), or carbapenem-resistant Pseudomonas aeruginosa (CRPA).

30. 23. The method of claim 21 or 22, wherein the bacterium is selected from the group consisting of isolates phenotypically characterized as carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, colistin-resistant Escherichia coli, carbapenem-resistant Acinetobacter baumannii (CRAB), or carbapenem-resistant Pseudomonas aeruginosa (CRPA).

31. 21. The pharmaceutical composition of claim 20, wherein the compound is less nephrotoxic than polymyxin B and / or colistin.

32. The method described in claim 21 or 22, wherein the compound is less nephrotoxic than polymyxin B and / or colistin.

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