Prodrugs of boron compounds and their use in treatment of bacterial infections

Abstract

The present application describes prodrugs of antimicrobial organoboron compounds of Formula I, or salts thereof, and pharmaceutical compositions thereof, as well as methods of use and methods of preparation thereof. # imgabs0 #

Description

Technical Field

[0001] The present application describes prodrugs of antimicrobial boron organic compounds, pharmaceutical compositions thereof, methods of use thereof, and methods of preparation thereof. Background Art

[0002] Due to the increase in bacterial resistance, new antibacterial compounds are needed to treat microbial infections. These new drugs need to have useful activity against major mammalian pathogens, including Gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae, and major Gram-positive bacteria, such as multidrug-resistant Staphylococci and Streptococci. Drugs that work by new mechanisms of action are particularly advantageous to avoid undesirable cross-resistance with existing drugs.

[0003] For many patients with bacterial infections, oral formulations are the most appropriate option. The advantages of oral over intravenous routes are the absence of catheter-related infections, reduced drug costs, and reductions in hidden costs, such as the need for health professionals and equipment to administer intravenous antibiotics. For those patients who require long-term treatment, oral therapy is particularly important to improve patient compliance.

[0004] Several antimicrobial boron organic compounds have been previously described in PCT applications WO 2008 / 157726 and WO 2010 / 080558 and US application US 2009 / 0227541. To date, none of these compounds have been approved for use in human anti-infective treatments.

[0005] Boron organo compounds (shown below) are described in US application US2013 / 0165411. This class of compounds is particularly active against Gram-negative bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae. In addition, this type of molecule has good efficacy in a Pseudomonas aeruginosa neutropenic mouse thigh infection model administered subcutaneously. However, there are no reports of oral formulations of this molecule to date. In fact, many antibiotics, including cephalosporins, can only be administered via intravenous injection. Drugs with poor oral bioavailability are not suitable for oral drug development due to the lack of sufficient drug exposure. Poor oral bioavailability may also require higher doses, which may cause additional side effects.

[0006] There are two main approaches to increase membrane permeability and thus oral absorption of a compound. One involves changing the chemical structure, and the other involves developing a formulation without changing the molecular structure. The former can be achieved by attaching a relatively small structural modification group (such as an alkyl or acyl group) to a suitable substituent (such as a carboxyl or amino group) within the drug to form a prodrug.

[0007] The preferred compounds provided herein are stable in the prodrug form before absorption, and exhibit better absorption due to the unique prodrug form. After administration to a mammal in need of treatment, these prodrug molecules are rapidly converted to active drugs chemically and / or enzymatically in body regions (such as the intestine, liver and / or plasma). This required conversion to active drugs can occur during and / or after absorption.

[0008] However, it is difficult to develop an ideal prodrug that meets all of the above conditions. For example, a prodrug with an ester bond may be more susceptible to hydrolysis, which may affect the chemical stability before absorption. Amide bonds can cause significant changes in physical properties, which in turn may have a negative impact on the permeability of the membrane (such as oral absorption capacity). In addition, amide bonds are less susceptible to hydrolysis, which may affect the biotransformation of the compound to the active form and the plasma concentration of the active form. In addition, it is difficult to predict the pharmacokinetic characteristics of prodrugs because the enzyme that controls the biotransformation of prodrugs to the active form is substrate-specific, and in particular, the steric hindrance of the substituents inserted to form prodrugs can prevent the reaction of the enzyme. For these reasons, it is impossible to predict how or whether the prodrug will increase the plasma concentration of the active form, whether the prodrug will increase the permeability of the membrane, and / or whether the prodrug will be converted into the active form in vivo. Summary of the invention

[0009] The present application describes novel prodrugs of boron compounds with high antibacterial activity against Gram-negative bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae.

[0010] The prodrugs described herein have been found to enhance the in vivo exposure of the corresponding active form in animal experiments using the active form and the prodrug as test drugs.

[0011] In one aspect, the present application provides a compound of formula I: or a pharmaceutically acceptable salt, complex or tautomer thereof, wherein: R 1 Selected from H, C 1-24 Alkyl-C(=O)-, C 1-24 Alkoxy-C(=O)-, C 3-7 Cycloalkyl-C(═O)-, heteroalkyl-C(═O)-, aryl-C(═O)-, heteroaryl-C(═O)-, and (5-methyl-1,3-dioxol-2-one-4-yl)methyl; and R 2 Selected from C 1-24 Alkyl-C(=O)-, C 1-24 Alkoxy-C(=O)-, C3-7 Cycloalkyl-C(═O)-, heteroalkyl-C(═O)-, aryl-C(═O)-, heteroaryl-C(═O)-, and (5-methyl-1,3-dioxol-2-one-4-yl)methyl; or R 1 and R 2 Together, they form a heterocyclic group selected from 1,3-dioxane, 2-C 1-6 -alkyl-1,3-dioxane, 2,2-di(C 1-6 alkyl)-1,3-dioxane, 2-methyl-1,3-dioxane, 2-aryl-1,3-dioxane, 2-(2-carboxyphenyl)-1,3-dioxane, 2-(4-carboxyphenyl)-1,3-dioxane or 2-C 1-6 -alkyl OC(=O)-1,3-dioxane; each of which is optionally substituted by one to four R 3 replace; R 3 is independently selected at each occurrence from a group comprising halogen, hydroxy, C1-C6 alkyl, C3-C6 cycloalkyl, C1-C6 alkoxy, aryl and heteroaryl; or When attached to adjacent carbons, the two R 3 The groups together with the carbon to which they are attached form a fused C3-C6 cycloalkyl; or when attached to the same carbon, the two R 3 The groups together with the carbon to which they are attached form a spiro C3-C6 cycloalkyl; Each R 3 Optionally independently substituted with one to three fluoro, hydroxy or C1-C3 alkyl.

[0012] In a preferred embodiment of Formula I, R 1 and R 2 All are alkyl.

[0013] In another preferred embodiment of Formula I, R 1 and R 2 All are C1-C6 alkyl-C(=O)-.

[0014] In another aspect, the present application provides a compound of formula II: or a pharmaceutically acceptable salt thereof; wherein: R 4 Selected from C 1-24 Alkoxy-C(=O)-, C 3-7 Cycloalkyl-C(═O)-, heteroalkyl-C(═O)-, aryl-C(═O)-, heteroaryl-C(═O)- and (5-methyl-1,3-dioxol-2-on-4-yl)methyl.

[0015] In another aspect, the present application provides a pharmaceutical composition comprising a therapeutically effective amount of a compound of Formula I or Formula II, or a pharmaceutically acceptable salt, complex or tautomer thereof, and a pharmaceutically acceptable carrier.

[0016] In another aspect, the present application provides a pharmaceutical composition comprising a compound of Formula I or Formula II or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

[0017] In another aspect, the present application provides a method for treating a microbial infection in a mammal, comprising administering a therapeutically effective amount of a compound of Formula I or Formula II, or a pharmaceutically acceptable salt, complex, or tautomer thereof to a mammal in need of treatment. The compound of Formula I or Formula II, or a pharmaceutically acceptable salt, complex, or tautomer thereof, can be administered orally, parenterally, transdermally, topically, rectally, or intranasally in the form of a pharmaceutical composition, including a solution or powder composition for inhalation.

[0018] In another aspect, the compound or a pharmaceutically acceptable salt, complex or tautomer thereof is orally administered to a mammal in the form of a pharmaceutical composition.

[0019] In another aspect, the present application provides a method for treating mycobacterial microbial infection in humans or other warm-blooded animals by administering a therapeutically effective amount of a compound of Formula I or Formula II or a pharmaceutically acceptable salt thereof to a subject in need of treatment. The compound of Formula I or Formula II can be administered orally, parenterally, transdermally, topically, rectally or intranasally in the form of a pharmaceutical composition.

[0020] In another aspect, the present application provides compositions and methods for treating microbial infections caused by microorganisms selected from Gram-negative bacteria, including but not limited to Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae.

[0021] In one embodiment, the method is used to treat skin, soft tissue, respiratory tract, blood, intra-abdominal, urinary or ocular infections.

[0022] In another aspect, the present application provides novel intermediates and methods for preparing compounds of formula I. DETAILED DESCRIPTION

[0023] Unless otherwise stated, the following terms used in the specification and claims have the following meanings.

[0024] The carbon atom content of various hydrocarbon-containing moieties is indicated by prefixes indicating the minimum and maximum number of carbon atoms in the moiety, i.e., the prefix Ci-j represents the carbon atom fraction from integer "i" to integer "j". Thus, for example, C 1-7 The alkyl group refers to an alkyl group having 1 to 7 carbon atoms (inclusive).

[0025] The terms "alkyl", "alkenyl" and the like refer to straight and branched chain groups, but reference to a single group such as "propyl" includes only straight chain groups, while branched chain isomers such as "isopropyl" include only branched chain groups. Alkyl, alkenyl and the like groups may be optionally substituted with one, two or three radicals selected from halogen, aryl, Het 1 or Het 2 Representative examples include, but are not limited to, difluoromethyl, 2-fluoroethyl, trifluoroethyl, -CH=CH-aryl, -CH=CH-Het 1 , -CH2-phenyl, etc.

[0026] The term "cycloalkyl" refers to a cyclic saturated monovalent hydrocarbon group having 3 to 6 carbon atoms, such as cyclopropyl, cyclohexyl, etc. The cycloalkyl group may be optionally substituted by one, two or three alkyl radicals selected from halogen, aryl, Het 1 or Het 2 substituted by a substituent.

[0027] The term "heteroalkyl" refers to an alkyl or cycloalkyl group as defined above having a radical selected from N, O or S(O) n A heteroatom substituent, wherein n is an integer from 0 to 2, including hydroxyl (OH), C 1-4 Alkoxy, amino, thio (-SH), etc. Representative substituents include -NR a R b , OR a or -S(O) n R c , where R a It is hydrogen, C 1-4 Alkyl, C 3-6 cycloalkyl, optionally substituted aryl, optionally substituted heterocycle, or -COR (wherein R is C 1-4 Alkyl); R b It is hydrogen, C 1-4 Alkyl, -SO2R (where R is C 1-4 Alkyl or C 1-4 hydroxyalkyl), -SO2NRR' (wherein R and R' are independently hydrogen or C 1-4 alkyl), -CONR'R" (wherein R' and R" are independently hydrogen or C 1-4 alkyl); n is an integer from 0 to 2; and R c It is hydrogen, C 1-4 Alkyl, C 3-6 Cycloalkyl, optionally substituted aryl or NRa R b , where R a and R b As defined above. Representative examples include, but are not limited to, 2-methoxyethyl (-CH2CH2OCH3), 2-hydroxyethyl (CH2CH2OH), hydroxymethyl (-CH2OH), 2-aminoethyl (-CH2CH2NH2), 2-dimethylaminoethyl (CH2CH2NHCH3), benzyloxymethyl, thiophen-2-ylthiomethyl, and the like.

[0028] The term "halogen" refers to fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

[0029] The term "aryl" refers to phenyl, biphenyl or naphthyl, which may be optionally substituted with 1-3 substituents independently selected from halogen, -C 1-4 Alkyl, -OH, -OC 1-4 Alkyl, -S(O) n C 1-4 Alkyl, wherein n is 0, 1 or 2, -C 1-4 Alkyl NH2, -NHC 1-4 alkyl, -C(=O)H or -C=N-ORd, wherein R d is hydrogen or -C 1-4 alkyl.

[0030] Het 1 is independently at each occurrence a C-linked 5- or 6-membered heterocyclic ring having 1 to 4 heteroatoms selected from oxygen, nitrogen and sulfur within the ring. 2 is independently at each occurrence an N-linked 5 or 6 membered heterocyclic ring having 1-4 nitrogens and optionally having one oxygen or sulfur within the ring.

[0031] "Optional" or "optionally" means that the subsequently described event or circumstance may occur, but need not occur, and the description includes instances where the event or circumstance occurs and instances where it does not occur. For example, "aryl optionally mono- or di-substituted with alkyl" means that alkyl may but need not be present, and the description includes instances where aryl is mono- or di-substituted with alkyl and instances where aryl is not substituted with alkyl.

[0032] Compounds that have the same molecular formula but differ in the nature or order of bonding of their atoms or in the arrangement of their atoms in space are called "isomers." Isomers that differ in the arrangement of their atoms in space are called "stereoisomers."

[0033] Stereoisomers that are not mirror images of one another are termed "diastereomers," while those that are non-superimposable mirror images of one another are termed "enantiomers." For example, when a compound has an asymmetric center, it is bonded to four different groups, a pair of enantiomers is possible. Enantiomers can be characterized by the absolute configuration of their asymmetric center, and described by the (R)- and (S)-steroid chemistry rules of Cahn and Prelog, or by the way the molecules rotate the plane of polarized light, and are designated as right- or left-handed (i.e., the (+) or (-)-isomer, respectively). Chiral compounds can exist as individual enantiomers or as mixtures thereof. A mixture containing equal proportions of enantiomers is called a "racemic mixture."

[0034] The compounds described herein may have one or more asymmetric centers; such compounds may therefore be produced as individual (R)- or (S)-stereoisomers or mixtures thereof. Unless otherwise indicated, the description or naming of a particular compound in the specification and claims is intended to include individual enantiomers and mixtures, racemic or otherwise, thereof. Methods for determining stereochemistry and separating stereoisomers are well known in the art (see discussion in Chapter 4 of "Advanced Organic Chemistry," 4th edition J. March, John Wiley and Sons, New York, 1992).

[0035] "Pharmaceutically acceptable carrier" means a carrier that can be used to prepare a pharmaceutical composition, which is generally safe, non-toxic, has no biological significance, and has no other undesirable content, and includes carriers that can be used in veterinary drugs and human drugs. "Pharmaceutically acceptable carrier" as used in the specification and claims includes one or more such carriers.

[0036] A "pharmaceutically acceptable salt" of a compound refers to a salt that is pharmaceutically acceptable and possesses the desired pharmacological activity of the parent compound. Such salts include: (1) Acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, etc.; or with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxybenzoyl)benzoic acid, ethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, 4-methylbicyclo[2.2.2]oct-2-ene-1-carboxylic acid, glucoheptanoic acid, 4,4'-methylenebis(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionic acid, trimethylacetic acid, tert-butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, etc.; or (2) Salts formed when the acidic protons present in the parent compound are replaced by metal ions, such as alkali metal ions, alkaline earth ions or aluminum ions; or when coordinated with organic bases such as ethanolamine, diethanolamine, triethanolamine, butanetriolamine, N-methylglucamine, etc.

[0037] The term "tautomer" refers to two or more forms or isomers of an organic compound that can be interconverted by a common chemical reaction called tautomerization, generally similar to the reaction described by Smith et al. in Advanced Organic Chemistry. 2001, 5th Ed. NY: Wiley Interscience., pp. 1218–1223. The concept of tautomerization is called tautomerization. Tautomerization may be accompanied by a change from a ring structure to an open structure, for example, as observed, by the interconversion between the cyclic pyran form and the open chain form of glucose through the formation and cleavage of the CO bond. The degree of tautomerism is generally affected by solvent effects, such as hydration with water and medium acidity. The relevant process for cyclic boron compounds may involve the formation and cleavage of the BO bond, as shown below:

[0038] "Treatment" for illness includes: (1) preventing a disease, that is, preventing clinical symptoms of the disease from developing in a mammal that may be exposed to or susceptible to the disease but does not yet experience or show symptoms of the disease, (2) inhibit the disease, i.e., prevent or reduce the development of the disease or its clinical symptoms, or (3) Relieve the disease, that is, cause the disease or its clinical symptoms to disappear.

[0039] "Therapeutically effective amount" refers to the amount of a compound that, when administered to a mammal to treat a disease, is sufficient to affect the treatment of the disease. The "therapeutically effective amount" will vary depending on the compound, the disease and its severity, and the age, weight, etc. of the mammal to be treated.

[0040] "Prodrug" refers to any compound that releases an active parent drug in vivo according to the compounds described herein when the prodrug is administered to a mammalian subject. Prodrugs of the compounds of the invention are prepared by modifying functional groups present in the compounds of the invention, which modifications can be cleaved in vivo to release the parent compound. In certain embodiments, prodrugs include compounds described herein, wherein a hydroxyl, sulfhydryl, amide, or amino group in the compound is bound to any group that can be cleaved in vivo to regenerate a free hydroxyl, amide, amino, or sulfhydryl group, respectively.

[0041] The term "mammal" refers to all mammals, including humans, livestock, and companion animals.

[0042] "Patient" refers to animals, such as mammals, including non-primates (such as cows, pigs, horses, cats, dogs, rats and mice) and primates (such as monkeys, such as cynomolgus monkeys, chimpanzees and humans), and for example humans. In certain embodiments, the patient is a human.

[0043] The compounds described herein are generally named according to the IUPAC or CAS naming system. Abbreviations well known to those of ordinary skill in the art can be used (e.g., "Ar" represents aryl, "Ph" represents phenyl, "Me" represents methyl, "Et" represents ethyl, "h" represents hours or hours, and "rt" or "rt" represents room temperature).

[0044] Illustrative Embodiments

[0045] The specific and preferred values ​​for radicals, substituents, and ranges listed below are for illustration only; they do not exclude other defined values ​​for radicals and substituents or other values ​​within defined ranges.

[0046] In some preferred compounds described in this application, C 1-4 The alkyl group may be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or an isomeric form thereof.

[0047] In some preferred compounds described in this application, C 3-6 The cycloalkyl group may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or an isomeric form thereof.

[0048] In some preferred compounds described in this application, C 1-4 The heteroalkyl group may be hydroxymethyl, hydroxyethyl or 2-methoxyethyl.

[0049] In some preferred compounds described herein, the halogen may be fluorine (F) or chlorine (Cl).

[0050] A preferred group of compounds of formula I includes:

[0051] Another preferred group of compounds of formula I includes:

[0052] Another group of preferred compounds of formula I includes:

[0053] Another group of preferred compounds of the formula I is also encompassed.

[0054] In some embodiments, the pharmaceutically acceptable salt of the preferred compound is the hydrochloride salt.

[0055] General synthetic method

[0056] In certain embodiments, the compounds described herein can be prepared according to one or more of the schemes discussed below. These methods can be used directly or can be significantly modified by a trained chemist to prepare key intermediates and certain compounds described herein.

[0057] Further general methods for the preparation of some bicyclic boron compounds are described, for example, in the publications US applications US2013 / 0165411 and US2009 / 0227541 and PCT application WO 2010 / 080558.

[0058] It should also be understood that, if desired, any racemic compound or intermediate described herein can be separated into asymmetric chiral materials of the desired optically active isomers using conventional means, including but not limited to chiral liquid chromatography or co-crystallization with a chiral auxiliary reagent (such as conventional commercially available chiral acids or amines).

[0059] Suitable synthesis sequences can be easily selected according to the specific structure described in the application, but in the field known to individuals practicing organic synthesis, such as the methods summarized in available chemical databases, such as in CAS Scifinder and Elesevier Reaxys. Based on these universal methods, the realization of preparing compounds described in the application is direct and can be practiced within the scope of general expertise. Some universal synthetic methods for preparing compounds described in the application are described in the following schemes 1-6 (non-restrictive, for illustration only).

[0060] A general method for synthesizing compounds of Formula I described herein is illustrated in General Scheme 1.

[0061] Scheme 1. General synthesis of prodrugs. Non-limiting examples of esterifying agents used for the conversion described in (a) include, but are not limited to, acid chlorides, acid anhydrides, or acids with EDC, etc.; The deprotecting agent used for the transformation described in (b) depends on the protecting group used. For example, in some embodiments, R a and R b Independently selected from H, Bn, Boc, Fmoc, Cbz and the like. Additional detailed synthetic schemes for synthesizing specific compounds described in this application are illustrated by the methods described in the following examples.

[0062] Example

[0063] Embodiments described in this application are described in the following examples, which are intended to illustrate but not to limit the scope of the present disclosure. Common abbreviations well known to one of ordinary skill in the art of synthesis are used throughout. 1 H NMR spectra (δ, ppm): recorded on a 300 MHz instrument using DMSO-d6 unless otherwise specified. Mass spectral data are provided for the positive ionization method. Unless otherwise specified, chromatography refers to silica gel chromatography. TLC refers to thin layer chromatography. HPLC refers to reverse phase HPLC. Unless otherwise specified, all reagents were either from commercial sources or prepared by conventional methods described in the existing literature.

[0064] Example 1

[0065] (2S)-3-Acetoxy-1-{[(3S)-3-(aminomethyl)-1-hydroxy-1,3-dihydrobenzo[2,1-c][1,2]oxaborol-7-yl]oxy}propan-2-yl acetate hydrochloride

[0066] Preparation scheme of the compound of Example 1:

[0067] Intermediate 2. To a solution of intermediate 1 (60 mg, 0.26 mmol, prepared as described in US application US2013 / 0165411) and pyridine (31 μL, 0.33 mmol) in DCM (2 mL) was added Ac2O (32 μL, 0.33 mmol) dropwise, and the resulting mixture was stirred for 2 hours. After the reaction was complete, the solvent was removed by concentration, and the residue was purified on pre-HPLC to give intermediate 2 (25 mg): MS (m / z): 438 [m+H].

[0068] Example 1

[0069] Intermediate 2 was dissolved in 5M HCl (2 mL) in dioxane at room temperature and the resulting mixture was stirred for 1 hour. The mixture was then lyophilized to afford the compound of Example 1 (16.9 mg) as a light yellow powder. MS (m / z): 338 [M+H]. 1 H NMR: (400MHz, D2O): 7.48 (t, J=8.0Hz, 1H); 7.01 (d, J=7.6Hz, 1H); 6.92 (dd, J=12.0, 8.0Hz, 1H); 5.35 (dd, J=7.4, 3 .0Hz, 1H); 4.35~4.17(m, 5H); 3.73~3.60(m, 1H); 3.56~3.51(m, 2H); 3.08~3.01(m, 1H); 1.99(s, 3H), 1.98(s, 3H).

[0070] The following compounds were synthesized according to the procedure described in Example 2.

[0071] Example 4

[0072] [(2S,6S)-2-(Aminomethyl)-4-boron-3,5,8-trioxacyclo[7.3.1.04,13]trideca-1(12),9(13),10-trien-6-yl]methyl-2-propionic acid methyl ester hydrochloride

[0073] The compound of Example 4 was prepared according to the method described in US application US2013 / 0165411.

[0074] Example 5

[0075] [(2S,6R)-2-(Aminomethyl)-4-boron-3,5,8-trioxacyclo[7.3.1.04,13]trideca-1(12),10-dien-6-yl]methanol hydrochloride

[0076] The compound of Example 5 was prepared according to the method described in US Application US2013 / 0165411.

[0077] Example 7

[0078] [(2S,6S)-2-(Aminomethyl)-4-boron-3,5,8-trioxacyclo[7.3.1.04,13]trideca-1(12),9(13),10-trien-6-yl]acetate methyl hydrochloride

[0079] The compound of Example 7 was prepared according to the method described in US application US2013 / 0165411.

[0080] Example 8

[0081] [(2S,6S)-2-(Aminomethyl)-4-boron-3,5,8-trioxacyclo[7.3.1.04,13]trideca-1(12),9(13),10-trien-6-yl]propanoic acid methyl ester hydrochloride

[0082] The compound of Example 8 was prepared according to the method described in US Application US2013 / 0165411.

[0083] Utility and testing

[0084] The compounds described herein are prodrugs, which are expected to be converted to the parent boron compounds to exert antibacterial effects. The antibacterial activity of the parent boron compounds has been disclosed in the U.S. application US2013 / 0165411. Therefore, the compounds described herein are useful antimicrobial agents and can be effective against many human and veterinary pathogens, including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae.

[0085] The in vitro activity of the compounds described in the present application can be evaluated by standard test procedures, such as the determination of the minimum inhibitory concentration (MIC) described in Approved Standard. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically, 3rd ed., 1993 published by the National Committee for Clinical Laboratory Standards, Villanova, Pennsylvania, USA. Low MIC values ​​represent high antimicrobial activity, while high MIC values ​​show reduced antimicrobial activity (higher drug concentrations required to eradicate pathogens in the latter case). Typically, MIC values ​​of about ≤4-8 μg / mL represent the therapeutic efficacy of antimicrobial drugs (i.e., suitable for treatment), while MIC values ​​≥16 μg / mL indicate a lack of therapeutically useful activity for the test compound.

[0086] The useful in vitro activity (potency) of representative compounds described herein against mycobacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae are shown in the MIC data in Table 1 below.

[0087] It is apparent from the data in Table 1 that the reference compound of Example 5 is highly active (MIC range is 2-4 μg / mL) against many Gram-negative bacteria including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae. Typical prodrug derivatives, the prodrug of Example 5, such as the compounds of Examples 2, 3, 4 and 8 are considered to be inactive.

[0088] Table 1. In vitro antibacterial activity of representative examples.

[0089] In addition to in vitro activity (potency determined as MIC), the potency or ability to eradicate bacterial pathogens in vivo is critical to the survival of mammals under treatment. It is well known that compounds with similar in vitro antimicrobial potency (MIC) may exhibit significantly different activities in vivo. This may result in the desired therapeutic effect for some effective compounds, or the lack of any useful anti-infective effect for other ineffective compounds. This is critical to the actual treatment outcome and is determined by a variety of factors that affect the behavior of the compound in vivo, such as its absorption, distribution, metabolism and excretion.

[0090] Furthermore, in vivo activity (or therapeutic efficacy) is generally the most critical activity for a prodrug compound, which is generally inactive in vitro and releases the active drug upon administration to a mammal in need of treatment.

[0091] In order to establish the efficacy of the compounds described in the present application in vivo, the Pseudomonas aeruginosa mouse lung infection model is implemented by administering test compounds similar to the method described in Andes et al. in Antimicrobial Agents and Chemotherapy, 2002, 46 (11), 3484-3489. In this model, the greater the reduction of colony forming units (CFU), the more favorable the treatment effect (the more bacteria are eradicated), and the smaller the reduction of colony forming units, the worse the effect (the less bacteria are eradicated). The antibacterial effect in vivo is also referred to as "efficacy", and the term "efficacy" is generally used for in vitro activity (expressed as MIC).

[0092] In Pseudomonas aeruginosa ICR mice (mice were randomly divided into groups, 6 mice per group) lung infection, reference example 5 was orally administered at 10 mg / kg per day. Compared with the untreated control group, the reference compound of Example 5 showed weak antibacterial efficacy and caused a 0.53 log reduction in CFU in the lung. As an orally administered prodrug, the compounds of Examples 2 and 8 were also administered by oral gavage at a dose of 10 mg / kg per day. Although the prodrug itself does not have antibacterial efficacy, it shows good in vivo efficacy. Surprisingly, when administered at 10 mg / kg, the efficacy of the compounds of Examples 2 and 8 was much better than that of the reference compound of Example 5, with a reduction of 1.77 and 0.82 log in the lung CFU. The data strongly support that the prodrugs of Examples 2 and 8 are converted into the reference compounds of Example 5 after oral administration to exert antibacterial activity. The data also support a high conversion rate.

[0093] Table 2 Data of the Pseudomonas aeruginosa mouse lung infection model.

[0094] po, oral administration, oral suspension used in this application.

[0095] In order to further illustrate the therapeutic potential of drug compounds, pharmacokinetic (PK) data are used to establish key parameters for predicting treatment outcomes, such as monitoring the area under the curve (AUC) of systemic drug concentration over time. Therefore, a higher AUC value indicates a greater exposure to the drug, which is generally associated with a greater therapeutic potential because the amount of drug available to combat mammalian infections is higher. On the contrary, a lower AUC value indicates a reduced exposure to the drug under study, resulting in a reduced amount of antibiotics available to combat bacterial infections. For this reason, the compounds described in the present application are tested in an oral rat PK model, using a method similar to that described in the monograph Current Protocols in Pharmacology, 2005, 7.1.1-7.1.26, John Wiley & Sons, Inc.

[0096] All compounds were administered to SD rats by intravenous injection (iv) or oral gavage (rats were randomly divided into groups, 3 rats per group). Since the prodrug is expected to be converted to the parent molecule in vivo, only the parent compound (compound of Example 5) was tested for all samples. As shown in Table 3, the parent compound of Example 5 has a low oral bioavailability of only 15%. This low bioavailability, as well as the low exposure (AUC) and C max This makes it unsuitable for development as an oral drug. Surprisingly, the pharmacokinetic data of the compounds of the present invention show that at the same dose of 5 mg / kg, the systemic exposure (AUC) and Cmax are significantly improved. The AUCs of Examples 1, 2, 3, 4, 6, 7 and 8 are all significantly higher than the AUC of Example 5, even though the molecular weights of these prodrugs are higher than that of Example 5. For example, the compound of Example 2 shows AUC and Cmax of max The results showed that the exposure and C max The results are significantly improved by 3.4-fold and 3-fold, respectively, which is consistent with the efficacy improvement described in Table 2. Due to the introduction of the prodrug substructure, the prodrug generally has a larger molecular weight, so the AUC is corrected by dose and molecular weight (MW) to obtain the AUC per mole to compare the efficacy between the prodrugs. Importantly, compared with the compound of Example 4 previously described in US2013 / 0165411, the compound of Example 2 also shows a significantly high AUC per mole.

[0097] Table 3 Pharmacokinetic study of selected examples in rats.

[0098] The AUC per mole is the AUC corrected for dose and molecular weight,

[0099] In addition, in the lung distribution study conducted in Balb / C mice (three mice per time point), the exposure of Example 2 in the lung was much higher than that in the plasma (assessed by the area under the lung / plasma concentration-time curve (AUC)). As shown in Table 4, the compounds of Examples 5 and 2 were administered at 10 mg / kg by intravenous injection and oral administration, respectively. In the analysis of Example 2, the concentrations of the parent compound (Example 5) and the prodrug (Example 2) in plasma and lung were determined. The prodrug (Example 2) was rapidly converted to Example 5, and the prodrug was almost undetectable in plasma. Compared with the AUC of Example 5 administered by intravenous injection, the oral bioavailability of Example 5 produced by Example 2 was 83.95% in mice. Despite the rapid conversion of the prodrug, surprisingly, more Example 5 was detected in the lungs, with a lung / plasma AUC ratio of 5.24, almost 2.2 times the AUC of Example 5 administered by intravenous injection. The higher accumulation of the drug in the lungs is particularly useful for treating pneumonia, which is also consistent with the superior efficacy of Example 2 in the Pseudomonas aeruginosa mouse lung infection model (Table 2).

[0100] Table 4 Lung and plasma distribution of the drug of Example 5 and its prodrug of Example 2 in mice.

[0101] This significant increase in in vivo exposure (AUC) in plasma and lungs after oral administration of the compound of Example 2 is completely unexpected and very surprising. Other related compounds provided herein also show surprising increases in in vivo exposure. Therefore, the pharmacokinetic data of the compound of Example 2 in the rat model of oral administration show that compared with the parent compound of Example 5, the in vivo exposure and C max Significantly improved.

[0102] The above complete representative data reveal the surprisingly superior therapeutic potential of the compounds described in the present application, with beneficial unexpected advantages in terms of efficacy, efficacy and exposure. The significant and surprising improvement of three distinct key parameters of the antibacterial compounds provided in the present application provides significant benefits for the treatment of humans or mammals, including but not limited to convenient long-term oral administration, reduced effective drug dosage and reduced possible side effects.

[0103] Administration and drug formulation

[0104] In general, the compounds described herein are administered in a therapeutically effective amount by any acceptable mode of administration for similar use preparations. For example, the compounds described herein can be administered orally, parenterally, transdermally, topically, rectal or intranasally. The actual amount of the compounds described herein (i.e., active ingredients) will depend on many factors, such as the severity of the disease to be treated (i.e., infection), the age and relative health of the subject, the effectiveness of the compounds used, the route of administration and form and other factors, all of which are within the scope of the attending clinician.

[0105] The data obtained from the cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage of such compounds preferably lies within a range that includes the ED with little or no toxicity. 50 The dosage may vary within this range depending on the dosage form employed and the route of administration utilized. For any compound used in the methods described herein, the therapeutically effective dose can be estimated initially from cell culture assays. A dose can be formulated in animal models to achieve a circulating plasma concentration range that includes the IC determined in cell culture. 50 (ie, the concentration of the test compound which achieves a half-maximal inhibition of symptoms). Such information can be used to more accurately determine useful doses in humans. Levels in plasma can be measured, for example, by high performance liquid chromatography.

[0106] When used as a drug, the compounds described herein are generally administered in the form of a pharmaceutical composition. These compounds can be administered by a variety of routes, including oral administration, parenteral administration, transdermal administration, topical administration, rectal administration, and intranasal administration.

[0107] These compounds are effective as both injectable and oral compositions. Such compositions can be prepared in a manner well known in the pharmaceutical art and contain at least one active compound.

[0108] The present application also describes pharmaceutical compositions containing as active ingredients one or more compounds described herein and a pharmaceutically acceptable carrier. In preparing the compositions described herein, the active ingredient is typically mixed with an excipient, the excipient is diluted or enclosed in such a carrier, which may be in the form of a capsule, bag, paper or other container. When an excipient is used as a diluent, it may be a solid, semisolid or liquid material that acts as a vehicle, carrier or medium for the active ingredient. Thus, the composition may be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions and sterile packaged powders.

[0109] In preparing a formulation, it may be necessary to grind the active compound to provide a suitable particle size prior to combining with other ingredients. If the active compound is substantially insoluble, it is generally ground to a particle size of less than 200 mesh. If the active compound is substantially water-soluble, the particle size is generally adjusted by grinding to provide a substantially uniform distribution in the formulation, for example, about 40 mesh.

[0110] Some examples of suitable excipients include lactose, glucose, sucrose, sorbitol, mannitol, starch, gum arabic, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, sterile water, syrup and methylcellulose. The formulation may also include: lubricants, such as talc, magnesium stearate and mineral oil; wetting agents; emulsifiers and suspending agents; preservatives, such as methyl and propyl hydroxybenzoates; sweeteners; and flavoring agents. The compositions described herein can be prepared using procedures known in the art to provide rapid, sustained or delayed release of the active ingredient after administration to the patient.

[0111] The amount of active ingredient (ie, the compound described herein) in the pharmaceutical compositions and unit dosage forms thereof can be widely varied or adjusted depending on the particular application, the potency of the particular compound, and the desired concentration.

[0112] The composition is preferably formulated in a unit dosage form, each dose containing about 5 to about 100 mg, more usually about 10 to about 30 mg of active ingredient. The term "unit dosage form" refers to physically discrete units suitable as unit doses for human subjects and other mammals, each unit containing a predetermined amount of active material, which is calculated together with a suitable pharmaceutical excipient to produce the desired therapeutic effect. Preferably, the compound described in the present application is no more than about 20% by weight of the pharmaceutical composition, more preferably no more than about 15% by weight, and the rest is a pharmaceutically inert carrier.

[0113] The active compound is effective within a wide dosage range and is generally administered in a pharmaceutically or therapeutically effective amount. However, it should be understood that the actual amount of compound administered will be determined by the physician based on the relevant circumstances, including but not limited to the condition to be treated, the severity of the bacterial infection being treated, the selected route of administration, the actual compound administered, the age, weight and response of the individual patient, the severity of the patient's symptoms, etc.

[0114] In therapeutic uses for treating or combating bacterial infections in warm-blooded animals, the compound or its pharmaceutical composition can be administered orally, topically, transdermally and / or parenterally in a dose to achieve and maintain a concentration, i.e., a dose, or blood level of the active ingredient in the animal being treated, which will be antibacterial effective. Typically, such an antibacterial or therapeutically effective dose (i.e., effective dose) of the active ingredient will be in the range of about 0.1 mg / kg to about 100 mg / kg body weight / day, more preferably about 1.0 mg / kg to about 50 mg / kg body weight / day.

[0115] In order to prepare solid compositions such as tablets, the main active ingredient is mixed with a pharmaceutical excipient to form a solid preformulation composition containing a uniform mixture of compounds described herein. When these preformulation compositions are referred to as homogeneous, it means that the active ingredient is evenly dispersed throughout the composition so that the composition can be easily subdivided into equally effective unit dosage forms, such as tablets, pills, and capsules. The solid preformulation is then subdivided into a unit dosage form of the above type containing, for example, 0.1 to about 500 mg of the active ingredient described herein.

[0116] Tablet or pill described in the present application can coating or otherwise compound, to provide the dosage form with the advantage of prolonged action.For example, tablet or pill can comprise inner dosage component and outer dosage component, and the latter is the encapsulated form on the former.These two kinds of compositions can be separated by enteric layer, and enteric layer is used to resist the disintegration in the stomach, and allows inner component to enter duodenum or delay release intactly.Multiple materials can be used for this enteric layer or coating, for example comprise the mixture of multiple polymeric acid and polymeric acid and the material such as shellac, spermol and cellulose acetate.

[0117] Liquid forms into which the compositions described herein are incorporated for oral or injectable administration include aqueous solutions, appropriately flavored syrups, aqueous or oily suspensions, and emulsions flavored with edible oils, such as corn oil, cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical carriers.

[0118] Compositions for inhalation or insufflation include pharmaceutically acceptable solutions and suspensions, aqueous or organic solvents or mixtures thereof, and powders. Liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described above. Preferably, the composition is administered by oral or nasal respiratory route to achieve local or systemic effect. Compositions in preferably pharmaceutically acceptable solvents can be atomized by use of an inert gas. Nebulized solutions can be inhaled directly from the atomizing device, or the atomizing device can be connected to a mask tent or intermittent positive pressure respirator. Solution, suspension or powder compositions can be administered in an appropriate manner from a device for delivering the formulation, preferably orally or nasally.

[0119] Another preferred formulation used in the method described in the present application adopts a transdermal delivery device ("patch"). Such a transdermal patch can be used to provide the compound described in the present application with a continuous or discontinuous infusion of a controlled amount. The construction and use of transdermal patches for delivering pharmaceutical preparations are well known in the art. Referring to, for example, U.S. Patent No. 5,023,252, issued on June 11, 1991, incorporated herein by reference. This patch can be constructed for continuous, pulsating or on-demand delivery of pharmaceutical preparations.

[0120] Often, it is desirable or necessary to introduce the pharmaceutical composition directly or indirectly into the brain. Direct techniques generally involve placing a drug delivery catheter into the host's ventricular system to bypass the blood-brain barrier. One such implantable delivery system for delivering biological factors to specific anatomical regions of the body is described in U.S. Pat. No. 5,011,472, which is incorporated herein by reference.

[0121] Indirect techniques, which are generally preferred, generally involve formulating compositions that provide drug latentiation by converting hydrophilic drugs into lipid-soluble drugs. Latentiation is generally achieved by blocking hydroxyl, carbonyl, sulfate, and primary amine groups present on the drug to render the drug more lipid-soluble and readily transported across the blood-brain barrier. Alternatively, delivery of hydrophilic drugs can be enhanced by intra-arterial infusion of hypertonic solutions that can transiently open the blood-brain barrier.

[0122] Other suitable formulations for the compounds described herein can be found in Remington's Pharmaceutical Sciences, Mace Publishing Company, Philadelphia, PA, 17th edition (1985).

[0123] As mentioned above, the compound described in the present application is applicable to the above-mentioned various drug delivery systems. In addition, in order to improve the serum half-life in vivo of the administered compound, the compound can be encapsulated, introduced into the lumen of the liposome, prepared as a colloid, or other conventional techniques for providing extended compound serum half-life can be used. Various methods can be used to prepare liposomes, such as described in U.S. Patents 4,235,871,4,501,728 and 4,837,028 of, for example, Szoka et al., each of which is incorporated herein by reference.

[0124] As described above, the compound administered to the patient is in the form of the above-mentioned pharmaceutical composition. These compositions can be sterilized by conventional sterilization techniques, or can be aseptically filtered. The resulting aqueous solution can be packaged and used as is, or lyophilized, and the lyophilized preparation is combined with a sterile aqueous carrier before administration. The pH of the compound preparation is generally 3 to 11, more preferably 5 to 9, and most preferably 7 to 8. It should be understood that the use of some of the above-mentioned excipients, carriers or stabilizers will lead to the formation of drug salts.

[0125] The disclosure of each patent, patent application and publication (such as journals, articles and / or textbooks) cited in this application is fully incorporated into this application by reference. In addition, as used in this application and the appended claims, singular articles such as "a", "an" and "one" are intended to refer to the singular or plural. Although the present application describes embodiments in conjunction with preferred aspects, those of ordinary skill in the art, after reading the foregoing description, can affect the changes to the embodiments described in this application, the replacement of equivalents and other types of changes. Each aspect described above can also include or incorporate such changes or aspects disclosed about any or all other aspects. The description of this application is also not limited to the specific aspects described in this application, which is intended to be a single illustration of the various aspects provided by this application. Without departing from its spirit and scope, many modifications and changes described in this application can be made, which will be obvious to those skilled in the art. In addition to the methods listed in this application, the functional equivalent methods within the scope of this specification will be obvious to those skilled in the art from the foregoing description. It should be understood that this specification is not limited to specific methods, reagents, process conditions, materials, etc., and of course these methods, reagents and materials can change. It should also be understood that the terminology used herein is for describing particular aspects only and is not intended to be limiting. Therefore, this specification is to be regarded as illustrative.

Claims

1. Compounds of formula I: or a pharmaceutically acceptable salt, complex or tautomer thereof; in: R 1 Selected from H, C 1-24 Alkyl-C(=O)-, C 1-24 Alkoxy-C(=O)-, C 3-7 Cycloalkyl-C(═O)-, heteroalkyl-C(═O)-, aryl-C(═O)-, heteroaryl-C(═O)-, and (5-methyl-1,3-dioxol-2-one-4-yl)methyl; and R 2 Selected from C 1-24 Alkyl-C(=O)-, C 1-24 Alkoxy-C(=O)-, C 3-7 Cycloalkyl-C(═O)-, heteroalkyl-C(═O)-, aryl-C(═O)-, heteroaryl-C(═O)-, and (5-methyl-1,3-dioxol-2-one-4-yl)methyl; or R 1 and R 2 Together, they form a heterocyclic group selected from 1,3-dioxane, 2-C 1-6 -alkyl-1,3-dioxane, 2,2-di(C 1-6 alkyl)-1,3-dioxane, 2-methyl-1,3-dioxane, 2-aryl-1,3-dioxane, 2-(2-carboxyphenyl)-1,3-dioxane, 2-(4-carboxyphenyl)-1,3-dioxane, 2-C 1-6 -alkyl OC(=O)-1,3-dioxane; each of which is optionally substituted by one to four R 3 replace; R 3 is independently selected at each occurrence from a group comprising halogen, hydroxy, C1-C6-alkyl, C3-C6-cycloalkyl, C1-C6-alkoxy, aryl and heteroaryl; or Two R's 3 groups when attached to adjacent carbons and taken together with the carbons to which they are attached are a fused C3-C6 cycloalkyl; or Two R's 3 The groups when attached to the same carbon and taken together with the carbon to which they are attached are spiro C3-C6 cycloalkyl; wherein each R 3 Optionally substituted independently with 1-3 fluorine or hydroxy and C1-C3 alkyl.

2. The compound according to claim 1 is selected from: or a pharmaceutically acceptable salt, complex or tautomer thereof.

3. The compound according to claim 1 is selected from: or a pharmaceutically acceptable salt, complex or tautomer thereof.

4. The compound according to any one of claims 1 to 3, or a pharmaceutically acceptable salt, complex or tautomer thereof, characterized in that: The pharmaceutically acceptable salt is hydrochloride.

5. A method for treating microbial infection in mammals, comprising administering to a mammal in need of treatment a therapeutically effective amount of a compound according to any one of claims 1 to 4 or a pharmaceutically acceptable salt, complex or tautomer thereof.

6. The method according to claim 5, characterized in that The compound or its pharmaceutically acceptable salt, complex or tautomer is administered to a mammal orally, parenterally, transdermally, topically, rectally or intranasally in the form of a pharmaceutical composition.

7. The method according to claim 6, characterized in that The compound or its pharmaceutically acceptable salt, complex or tautomer is orally administered to a mammal in the form of a pharmaceutical composition.

8. The method according to claim 5, characterized in that The microbial infection is caused by Gram-negative bacteria selected from the group consisting of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae.

9. The method according to claim 5, characterized in that The infection is of the skin, soft tissue, respiratory tract, blood, intra-abdominal cavity, urine or eyes.

10. A pharmaceutical composition, characterized in that The invention comprises a therapeutically effective amount of the compound according to any one of claims 1 to 4, or a pharmaceutically acceptable salt, complex or tautomer thereof, and a pharmaceutically acceptable carrier.

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