ZA200504939B - Antibiotics containing borinic acid complexes and methods of use - Google Patents

Description

ANTIBIOTICS CONTAINING BORINIC ACID

COMPLEXES AND METHODS OF USE

. 5

This application claims priority of U.S. Provisional Application Serial

No. 60/434,375, filed 18 December 2002, Serial No. 60/436,095, filed 23

December 2002, and Serial No. 60/437,849, filed 3 January 2003, the disclosures of which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to the field of antibiotics and particularly antibacterial and antifungal compounds and uses thereof. Methods for preparing and using these antibiotics, and pharmaceutical compositions thereof, are also provided.

BACKGROUND OF THE INVENTION

One hallmark of the modern era of medicine has been the decline in morbidity and mortality associated with bacterial and fungal infections.

However, misuse of conventional antibiotics and natural selection of the infectious bacterial population has resulted in the development of varying degrees of drug resistance by most bacterial infectious agents to most antibiotic agents. In severe cases, such as MRSA (Multidrug-Resistant ] StaphA), one or only a few antibiotics are currently effective. In addition, the existence of immunodeficiency syndromes results in additional incidence of opportunistic infections requiring intensive antibiotic treatment.

Thus, there continues to be a need in the medical arts for novel, more » effective, antibiotic compounds, especially for treating bacterial infections, that . are resistant to currently available therapies.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention relates to antibiotic compounds. The antibiotic compounds of the invention are borinate derivatives, especially borinic acid complexes, and include such compounds as derivatives of hydroxyquinolines, picolinic acids and imidazoles.

The antibiotic compounds are also provided as pharmaceutical compositions that can be administered to an animal, most preferably a human, for treatment of a disease having a bacterial or fungal etiology, or an opportunistic infection with a bacteria or fungus in an animal, most preferably a human, in an immunologically compromised or debilitated state of health.

In preferred embodiments, the compounds of the invention are those having the structures given by Formulas 1 or 2, with preferred substituents as disclosed herein.

The invention also provides methods for preparing the antibiotic compounds and pharmaceutical compositions thereof, and methods of using said antibiotics therapeutically. Kits and packaged embodiments of the antibiotic compounds and pharmaceutical compositions of the invention are also contemplated. } 2 (A

The invention also relates to methods of treating infections, preferably bacterial and/or fungal infections, using the antibiotic compounds disclosed herein. ’ 5

DETAILED DESCRIPTION OF THE INVENTION

This invention provides antibiotics, and specifically antibacterial and anti-fungal compounds, useful in treating and/or preventing bacterial infections.

The invention comprises a compound having the structure with formula : ok OO al ok (9) CH m

R\./ } AVE .

FE ’ N AS or AB / NN

R* R*

Formula 1 oo Formula 2 wherein B is boron, O is oxygen, mis 0, 1, 0r2, wherein R* and R** are each independently selected from substituted or unsubstituted alkyl (Cy - C4), substituted or unsubstituted cycloalkyl (Cs -

Ce), substituted or unsubstituted vinyl, substituted or unsubstituted alkynyl, substituted or unsubstituted benzyl, substituted or unsubstituted phenyl, and substituted or unsubstituted heterocycle, ; and wherein z is 0 or 1 and when zis 1, Ais CH, CR" or N, and wherein D is N, CH, or CR", and wherein E is H, OH, alkoxy or N-(morpholinyl)ethoxy 3 and wherein r is 1 or 2, and wherein when ris 1, G is =O (double- bonded oxygen) and when ris 2, each G is independently H, methyl, ethyl or propyl, . wherein R'is selected from (CH,)«xOH (where k = 1, 2 or 3), CH,NH,,

CHyNH-alkyl, CH,N(alkyl)2, CO,H, COqalkyl, CONH;, OH, alkoxy, aryloxy, SH, ' S-alkyl, S-aryl, SQ;alkyl, SO3H, SCF3, CN, halogen, CF3, NO;, NH,, 2*-amino, 3*-amino, NH,SO; and CONH,, and wherein J is CR" or N and wherein R®, R'® and R"' are each independently selected from the group consisting of hydrogen, alkyl, (CH2),OH (n = 1 to 3), CH;NH_,

CHzoNHalkyl, CHN(alkyl);, halogen, CHO, CH=NOH, CO,H, CO,-alkyl, S- alkyl, SOz-alkyl, S-aryl, NH,, alkoxy, CFs, SCF, NO,, SO3;H and OH, including salts thereof, especially all pharmaceutically acceptable salts.

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R** is a substituted or unsubstituted alkyl (C4 - C4) or R* and R** are each a substituted or unsubstituted alkyl (Cy - C4).

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R* is a substituted or unsubstituted cycloalkyl (Cs - Cg) or R* and R** are each a substituted or unsubstituted cycloalkyl (C3 - Cg).

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R** is a substituted or unsubstituted vinyl or R* and R** are each a substituted or unsubstituted vinyl. In a further preferred embodiment thereof, the vinyl has the structure }

R! R?

X R3 wherein R', R? and R® are each independently selected from the group consisting of hydrogen, alkyl, aryl, substituted aryl, benzyl, substituted benzyl, 4

(CH,) OH (where k = 1, 2 or 3), CH,NH,, CH,NH-alkyl, CH:N(alkyl),, CO-H, CO,alkyl,

CONH,, S-alkyl, S-aryl, SO.alkyl, SOsH, SCF3;, CN, halogen, CF; and NO,.

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R** is a substituted or unsubstituted alkynyl or R* and R** are each a , substituted or unsubstituted alkynyl. In a further preferred embodiment thereof the alkynyl has the structure == wherein R' is selected from the group consisting of hydrogen, alkyl, aryl, substituted aryl, benzyl, substituted benzyl, (CH2)xOH (where k = 1, 2 or 3), CH,NH.,

CH_NH-alkyl, CH,N(alky!),, CO,H, COjalkyl, CONH,, S-alkyl, S-aryl, SO.alkyl, SO3H,

SCF3, CN, halogen, CF; and NO,.

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R** is a substituted or unsubstituted phenyl or R* and R** are each a substituted or unsubstituted phenyl. In a further preferred embodiment thereof the phenyl has the structure

RE R7 > -~

R* RS wherein RY, R%, R®, R” and R® are each independently selected from the group consisting of hydrogen, alkyl, aryl, substituted aryl, benzyl, substituted benzyl, (CH,)OH (where k = 1, 2 or 3), CH,NH,, CH,NH-alkyl, CH,N(alkyl);, CO,H, COalkyl,

CONH,, CONHalkyl, CON(alkyl),, OH, alkoxy, aryloxy, SH, S-alkyl, S-aryl, SO,alkyl,

SOsH, SCF; CN, halogen, CFs, NO, NH,, 2°-amino, 3°-amino, NH,SO,,

OCH,CH:NH,;, OCH,CH,NHalkyl, OCH,CH,N(alkyl),, oxazolidin-2-yl, or alkyl substituted oxazolidin-2-yl. 5 . _ .

In a preferred embodiment of either of Formulas 1 or 2, one of

R* and R** is a substituted or unsubstituted benzyl or R* and R** are each a substituted or unsubstituted benzyl. In a further preferred embodiment thereof the benzyl has the structure

RE R’ fon pe

RY RS wherein RY, R®>, R®, R” and R® are each independently selected from the group consisting of alkyl, aryl, substituted aryl, benzyl, substituted benzyl, (CH,),OH (where k = 1, 2 or 3), CH,NH,, CH,NH-alkyl, CH,N(alkyl),, CO.H, CO,alkyl, CONH,,

CONHalkyl, CON(alkyl),;, OH, alkoxy, aryloxy, SH, S-alkyl, S-aryl, SO.alkyl, SO;H,

SCF; CN, halogen, CF;, NO,, NH,, 2°-amino, 3°-amino, NH,SO,, OCH,CH,NH.,

OCH,CH;NHalkyl, OCH,CH,N(alkyl)., oxazolidin-2-yl, or alkyl substituted oxazolidin- 2-yl.. :

In a preferred embodiment of either of Formulas 1 or 2, one of R* and

R** is a substituted or unsubstituted heterocycle or R* and R** are each a substituted or unsubstituted heterocycle. in a further preferred embodiment thereof the heterocycle has the structure

Ry Py. x7 Y or YZ x

R4 ={ Ry ={ wherein X = CH=CH, N=CH, NR! (wherein R'> = H, alkyl, aryl or benzyl), O, or S : : and wherein Y = CH or N 6 and wherein R', R?, and R® are each independently selected from the group consisting of hydrogen, alkyl, aryl, substituted aryl, benzyl, substituted benzyl, (CH;)xOH (where k = 1, 2 or 3), CH;NH,, CH,NH-alkyl, CH,N(alkyl)2, . COzH, COzalkyl, CONH_, S-alkyl, S-aryl, SO,alkyl, SO3H, SCF3, CN, halogen,

CF3and NO...

The structures of the invention also permit solvent interactions that may afford structures (Formulas 1B and 2B) that include atoms derived from the solvent encountered by the compounds of the invention during synthetic procedures and therapeutic uses. Thus, such solvent structures can especially insinuate themselves into the compounds of the invention between the boron and nitrogen atoms, thereby affording a ring size one or two atom larger than that discloses in the structures herein. For example, where the boron ring of a structure of the invention comprises 5 atoms, including, for example, the boron, a nitrogen, an oxygen and 2 carbons, insinuation of a solvent atom between the boron and nitrogen would afford a 7 membered ring. In one example, use of hydroxyl and amino solvents may afford structures containing an oxygen or nitrogen between the ring boron and nitrogen atoms to increase the size of the ring. Such structures are expressly contemplated by the present invention where

R*™™isHorakyl :

R41 B | N r a “3 peg (Ham

INT NN J or IY INT E a : te

Formula 1B (solvent adduct) Formula 2B (solvent adduct)

As used herein, the following terms have the stated meaning:

By "alkyl", "lower alkyl", and “C4-Cs alkyl” in the present invention is meant straight or branched chain alkyl groups having 1-6 carbon atoms, such as, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, 2- pentyl, isopentyl, neopentyl, hexyl, 2-hexyl, 3-hexyl, and 3-methyipentyi. . By "alkoxy", "lower alkoxy", and “C;-Cg alkoxy” in the present invention is meant straight or branched chain alkoxy groups having 1-6 carbon atoms, : such as, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec- butoxy, fert-butoxy, pentoxy, 2-pentyl, isopentoxy, neopentoxy, hexoxy, 2- hexoxy, 3-hexoxy, and 3-methylpentoxy.

By the term "halogen" in the present invention is meant fluorine, bromine, chlorine, and iodine.

By “cycloalkyl”, e.g., C3-C; cycloalkyl, in the present invention is meant cycloalkyl groups having 3-7 atoms such as, for example cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl. In the Cs-C; cycloalkyl groups, preferably in the Cs-C; cycloalkyl groups, one or two of the carbon atoms forming the ring can optionally be replaced with a hetero atom, such as sulfur, oxygen or nitrogen. Examples of such groups are piperidinyl, piperazinyl, morpholinyl, pyrrolidinyl, imidazolidinyl, oxazolidinyl, perhydroazepinyl, perhydrooxazapinyl, oxepanyl, and perhydrooxepanyl. Cj and C, cycloalkyl groups having a member replaced by nitrogen or oxygen include aziridinyl, azetidinyl, oxetanyl, and oxirany!.

By “aryl” is meant an aromatic carbocyclic group having a single ring (e.g. phenyl), multiple rings (e.g., biphenyl), or multiple condensed rings in which at least one is aromatic, (e.g., 1,2,34-tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl), which is optionally mono-, di-, or trisubstituted with, e.g., halogen, lower alkyl, lower alkoxy, lower alkylthio, trifluoromethyl, lower acyloxy, aryl, heteroaryl, and hydroxy. Preferred aryl groups include phenyl and naphthyl, each of which is optionally substituted as defined herein.

By “heteroaryl” is meant one or more aromatic ring systems of 5-, 6-, or 7-membered rings containing at least one and up to four heteroatoms selected from nitrogen, oxygen, or sulfur. Such heteroaryl groups include, for example, thienyl, furanyl, thiazolyl, imidazolyl, (is)oxazolyl, pyridyl, pyrimidinyl, (iso)quinolinyl, napthyridinyl, benzimidazolyl, and benzoxazolyl. Preferred heteroaryls are thiazolyl, pyrimidinyl, preferably pyrimidin-2-yl, and pyridyl.

Other preferred heteroaryl groups include 1-imidazolyl, 2-thienyl, 1-, or 2- quinolinyl, 1-, or 2- isoquinolinyl, 1-, or 2-tetrahydroisoquinolinyl, 2- or 3- furanyl and 2- tetrahydro-furanyl.

By “ligand” is meant a nitrogen-containing aromatic system which is capable of forming a dative bond with the Lewis acidic boron center, while appended as a borinate ester moiety. Such ligands are known to those trained in the arts. Examples are shown in the structures below. ]

OH OH OH

1 3 : 1 . 1 2 AN 7 N HOC NN ; 6 N~_ COM 3, = 30G 3 6 N 3 = 6 5 3 4 5 1 7 4 5 4 8-hydroxyquinoline 4-hydroxybenzimidazole 8-hydroxyquinoline- picolinicacid 2-carboxylic acid (pyridine-2-carboxylic acid)

CH,OH [Ne 83 6 A CR,0H 6 N CH,CO,H be Azy! i! 5 ~ 3 5 ~ 3 2-hydroxymethyl- 4-hydroxymethyl- 2-(hydroxymethyl)pyridine R = H 2-pyridylacetic acid 1N-benzylimidazole imidazole 2-(hydroxyisopropyl)pyridine R = Me

The compounds of the present invention have been implicated in the inhibition of key microbial enzymes, such as bacterial DNA methyltransferase.

Many of the compounds disclosed herein are selective inhibitors of methyltransferases in microbes, while not inhibitory for methyltransferases in mammals. However, the anti-bacterial and anti-fungal activity of the compounds of the invention is not limited to those with said enzyme inhibitory activity, nor is the latter effect necessarily essential to said therapeutic activity. .

The invention also provides embodiments of the compounds disclosed herein as pharmaceutical compositions. The pharmaceutical compositions of . the present invention can be manufactured in a manner that is itself known, e.g., by means of a conventional mixing, dissolving, granulating, dragee- : making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.

Pharmaceutical compositions for use in accordance with the present invention thus can be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries that facilitate processing of the active compounds into preparations that can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.

Non-toxic pharmaceutical salts include salts of acids such as hydrochloric, phosphoric, hydrobromic,. sulfuric, sulfinic, formic, toluenesulfonic, methanesulfonic, hydroxyethanesulfonic, nitric, benzoic, citric, tartaric, maleic, hydroiodic, alkanoic such as acetic, HOOC-(CH2),-CH3; where nis 0-4, and the like. Non-toxic pharmaceutical base addition salts include salts of bases such as sodium, potassium, calcium, ammonium, and functional equivalents. Those skilled in the art will recognize a wide variety of non-toxic pharmaceutically acceptable addition salts.

For injection, the compounds of the invention can be formulated in appropriate aqueous solutions, such as. physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer. For transmucosal and transcutaneous administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.

For oral administration, the compounds can be formulated readily by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to . be formulated as tablets, pills, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient to be treated. : Pharmaceutical preparations for oral use can be obtained with solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries, if desired, to obtain tablets. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethylicellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents can be added, such as the cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate.

Pharmaceutical preparations that can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with filler such as lactose, binders such as starches, and/or lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds can be dissolved or suspended in suitable liquids, such as fatty ails, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers can be added. All formulations for oral administration should be in dosages suitable for such administration. For buccal administration, the compositions can take the form of tablets or lozenges formulated in conventional manner.

For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebuliser, with the use of a suitable propellant, e.g., dichlorodiflucromethane,. trichlorofluoromethane,

dichlorotetra-fluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit can be determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g., gelatin

X for use in an inhaler, can be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

The compounds can be formulated. for parenteral administration by injection, e.g., by bolus injection or continuous infusion. Formulations for injection can be presented in unit dosage form, e.g., in ampoules or in multi- dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and/or dispersing agents.

Pharmaceutical formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form.

Additionally, suspensions of the active compounds can be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Aqueous injection suspensions can contain substances that increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension can also contain suitable stabilizers or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use. The compounds can also be formulated in rectal compositions such as suppositories or retention enemas, e.g., containing conventional suppository bases such as cocoa butter or other glycerides. . in addition to the formulations described previously, the compounds can also be formulated as a depot preparation. Such long acting formulations can be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds can be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble . salt.

A pharmaceutical carrier for the hydrophobic compounds of the invention is a cosolvent system comprising benzyl alcohol, a nonpolar surfactant, a water-miscible organic polymer, and an aqueous phase. The cosoivent system can be the VPD co-solvent system. VPD is a solution of 3% w/v benzyl alcohol, 8% w/v of the nonpolar surfactant polysorbate 80, and 65% w/v polyethylene glycol 300, made up to volume in absolute ethanol.

The VPD co-solvent system (VPD:5W) consists of VPD diluted 1:1 with a 5% dextrose in water solution. This co-solvent system dissolves hydrophobic compounds well, and itself produces low toxicity upon systemic administration. Naturally, the proportions of a co-solvent system can be varied considerably without destroying its solubility and toxicity characteristics.

Furthermore, the identity of the co-solvent components can be varied: for example, other low-toxicity nonpolar surfactants can be used instead of polysorbate 80; the fraction size of polyethylene glycol can be varied; other biocompatible polymers can replace polyethylene glycol, e.g. polyvinyl pyrrolidone; and other sugars or polysaccharides can substitute for dextrose.

Alternatively, other delivery systems for hydrophobic pharmaceutical compounds can be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. Certain organic solvents such as dimethyl sulfoxide also can be employed, although usually at the cost of greater toxicity. Additionally, the compounds can be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules can, depending on their chemical nature, release the compounds for a few weeks up to over 100 days.

Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein and nucleic acid stabilization can be employed.

The pharmaceutical compositions also can comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include but are not limited to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.

The compounds of the invention can be provided as salts with pharmaceutically compatible counterions. Pharmaceutically compatible salts can be formed with many acids, including but not limited to hydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, phosphoric, hydrobromic, sulfinic, formic, toluenesulfonic, methanesulfonic, nitic, benzoic, citric, tartaric, maleic, hydroiodic, alkanoic such as acetic, HOOC-(CH,),-CH3; where n is 0-4, and the like. Salts tend to be more soluble in aqueous or other protonic solvents that are the corresponding free base forms. Non-toxic pharmaceutical base addition salts include salts of bases such as sodium, potassium, calcium, ammonium, and the like. Those skilled in the art will recognize a wide variety of non-toxic pharmaceutically acceptable addition salts.

Pharmaceutical compositions of the compounds of the present invention can be formulated and administered through a variety of means, including systemic, localized, or topical administration. Techniques for formulation and administration can be found in "Remington's Pharmaceutical

Sciences,” Mack Publishing Co., Easton, PA. The mode of administration can be selected to maximize delivery to a desired target site in the body. Suitable routes of administration can, for example, include oral, rectal, transmucosal,

transcutaneous, or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intramedullary injections, as well as intrathecal, direct intraventricular, intravenous, intraperitoneal, intranasal, or intraocular . injections. : Alternatively, one can administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a specific tissue, often in a depot or sustained release formulation.

Pharmaceutical compositions suitable for use in the present invention include compositions wherein the active ingredients are contained in an effective amount to achieve its intended purpose. More specifically, a therapeutically effective amount means an amount effective to prevent development of or to alleviate the existing symptoms of the subject being treated. Determination of the effective amounts is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.

For any compound used in the method of the invention, the therapeutically effective dose can be estimated initially from cell culture assays, as disclosed herein. For example, a dose can be formulated in animal models to achieve a circulating concentration range that includes the

ECs (effective dose for 50% increase) as determined in cell culture, i.e., the concentration of the test compound which achieves a half-maximal inhibition of bacterial cell growth. Such information can be used to more accurately determine useful doses in humans. it will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, and rate of excretion, drug combination, the severity of the particular disease undergoing therapy and the judgment of the prescribing physician. . For administration to non-human animals, the drug or a phamaceutical composition containing the drug may also be added to the animal feed or : drinking water. It will be convenient to formulate animal feed and drinking water products with a predetermined dose of the drug so that the animal takes in an appropriate quantity of the drug along with its diet. It will also be convenient to add a premix containing the drug to the feed or drinking water approximately immediately prior to consumption by the animal.

Preferred compounds of the invention will have certain pharmacological properties. Such properties include, but are not limited to oral bioavailability, low toxicity, low serum protein binding and desirable in vitro and in vivo half-lives. 156 Assays may be used to predict these desirable pharmacological properties.

Assays used to predict bioavailability include transport across human intestinal cell monolayers, including Caco-2 cell monolayers. Serum protein binding may be predicted from albumin binding assays. Such assays are described in a review by Oravcova et al. (1996, J. Chromat. B 677: 1-27). Compound half-life is inversely proportional to the frequency of dosage of a compound. /n vitro half- lives of compounds may be predicted from assays of microsomal half-life as described by Kuhnz and Gieschen (Drug Metabolism and Disposition, (1998) volume 26, pages 1120-1127).. :

Toxicity and therapeutic efficacy of such compounds can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., for determining the LDs (the dose lethal to 50% of the population) and the EDsq (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and it can be expressed as the ratio between LDsy and

EDso. Compounds that exhibit high therapeutic indices are preferred. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage of such compounds lies preferably within a range of circulating concentrations that include the EDsp with little or no toxicity. The dosage can vary within this . range depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and : dosage can be chosen by the individual physician in view of the patient's condition. (See, e.g. Fingl et al, 1975, in "The Pharmacological Basis of

Therapeutics”, Ch.1, p.1).

Dosage amount and interval can be adjusted individually to provide plasma levels of the active moiety that are sufficient to maintain bacterial cell growth inhibitory effects. Usual patient dosages for systemic administration range from 100 - 2000 mg/day. Stated in terms of patient body surface areas, usual dosages range from 50 - 910 mg/m?/day. Usual average plasma levels 18 should be maintained within 0.1-1000 uM. In cases of local administration or selective uptake, the effective local concentration of the compound cannot be related to plasma concentration. :

The compounds of the invention are useful as antibiotics for the treatment of diseases of both animals and humans, including but not limited to actinomycosis, anthrax, bacterial dysentery, botulism, brucellosis, cellulitis, cholera, conjunctivitis, cystitis, diphtheria, bacterial endocarditis, epiglottitis, gastroenteritis, glanders, gonorrhea, Legionnaire’s disease, leptospirosis, bacterial meningitis, plague, bacterial pneumonia, puerperal sepsis, rheumatic fever, Rocky Mountain spotted fever, scarlet fever, streptococcal pharyngitis, syphilis, tetanus, tuberculosis, tularemia, typhoid fever, typhus, and pertussis.

The disclosures in this application of all articles and references, including patents, are incorporated herein by reference. :

The compounds of the invention comprise a novel class of broad- spectrum antibiotics. Medically-important bacterial species that provide appropriate targets for the antibacterial activity of the inhibitors of the invention include gram-positive bacteria, including cocci such as

Staphylococcus species and Streptococcus species; acid-fast bacterium, including Mycobacterium species; bacilli, including Bacillus species,

Corynebacterium species and Clostridium species; filamentous bacteria, : including Actinomyces species and Streptomyces species; gram-negative bacteria, including cocci such as Neisseria species and Acinetobacter species; bacilli, such as Pseudomonas species, Brucella species,

Agrobacterium species, Bordetella species, Escherichia species, Shigella species, Yersinia species, Salmonella species, Klebsiella species,

Enterobacter species, Haemophilus species, Pasteurella species, and

Streptobacillus species; spirochetal species, Campylobacter species, Vibrio species; and intracellular bacteria including Rickettsiae species and

Chlamydia species. :

Specific bacterial species that are targets for the antibiotics of the invention include Staphylococcus aureus; Staphylococcus epidermidis,

Staphylococcus saprophyticus, Streptococcus pyogenes; Streptococcus agalactiae; Streptococcus pneumoniae; Enterococcus. faecalis; Enterococcus faecium; Bacillus anthracis; Mycobacterium avium, Mycobacterium tuberculosis, Acinetobacter baumannii; ~~ Corynebacterium diphtheria;

Clostridium perfringens, Clostridium botulinum; Clostridium tetani: Neisseria gonorrhoeae; Neisseria meningitidis, Pseudomonas aeruginosa; Legionella pneumophila; Escherichia coli, Yersinia pestis, Haemophilus influenzae;

Helicobacter pylori; Campylobacter fetus, Campylobacter jejuni, Vibrio cholerae; Vibrio parahemolyticus; Trepomena pallidum; Actinomyces israeli;

Rickettsia prowazekii, Rickettsia rickettsii; Chlamydia trachomatis; Chlamydia psittaci, Brucella abortus, Agrobacterium tumefaciens; and Francisella tularensis.

In carrying out the procedures of the present invention it is of course to be understood that reference to particular buffers, media, reagents, cells,

culture conditions and the like are not intended to be limiting, but are to be read so as to include all related materials that one of ordinary skill in the art would recognize as being of interest or value in the particular context in which . that discussion is presented. For example, it is often possible to substitute one buffer system or culture medium for another and still achieve similar, if not : identical, results. Those of skill in the art will have sufficient knowledge of such systems and methodologies so as to be able, without undue experimentation, to make such substitutions as will optimally serve their purposes in using the methods and procedures disclosed herein.

The invention is described in more detail in the following non-limiting examples. it is to be understood that these methods and examples in no way limit the invention to the embodiments described herein and that other embodiments and uses will no doubt suggest themselves to those skilled in the 16 art

The compounds of this invention are evaluated for their antibacterial activity as per the guidelines and procedures prescribed by the National

Committee for Clinical Laboratory Standards (NCCLS) (cf., NCCLS Document

M7-A3, 1993 Antimicrobial Susceptibility Testing). :

Protocol for MIC Determination

A useful protocol for MIC determination is as follows: 1. Approximately 2.5 mg of the compounds to be tested was weighed into cryovials. 2. 5 mg/ml stock solutions were made by adding DMSO to the samples : accordingly.

3. 256 pg/ml working solutions were made by using the 5 mg/ml stock solutions and adding sterile distilled water accordingly. : 4. A Beckman 2000 Automated Workstation was programmed to load 96 well plates with broth and compounds as follows: -100 pl of the appropriate broth was added to columns 1-11 -200 pi of the appropriate broth was added to column 12 -100 pl of compounds at the 256 pg/ml working solution were added to column 1 (one compound per row) _Two-fold serial dilutions were done from column 1 to 10 -Column 11 served as the growth control 5. The 10 organism panel was plated from stock vials stored at -80°C and incubated for 24 hours at 34°C. The organisms were then sub-cultured and incubated for 24 hours at 34°C. -The inoculums were first prepared in sterile distilled water with a target of 0.09-0.11 absorbance at 620 hm wavelength -A 1/100 dilution was made into the appropriate broth -100 pl of broth with organism was added to columns 1-11 -Column 12 served as the blank control 6. The completed 96 well plates were incubated for 24 hours at 34°C.

The 96 well plates were then read using a Beckman Automated Plate

Reader at 650 nm wavelength. The MIC was determined through calculations involving the growth control (column 11) and blank control (column 12). : BORINATE COMPLEXES

This procedure was used to obtain the results in the following tables.

Representative microbiological data for the compounds 10 to 123 are shown in Tables 1 to 4 as MIC (Minimum Inhibitory Concentration) with the values i expressed as micrograms per ml. : Thus, the invention provides antibiotics that are generically called borinic acid complexes, most preferably derived from disubstituted borinic acids.

The synthesis of the compounds of the invention is accomplished in several formats. Reaction scheme #1 demonstrate the synthesis of the intermediate borinic acids, and their subsequent conversion to the desired borinic acid complexes. When R* and R** are identical, the reaction of two equivalents of an arylmagnesium halide (or aryllithium) with trialkyl borate, followed by acidic hydrolysis affords the desired borinic acid 5. When R* and

R** are not identical, the reaction of an equivalent of an arylmagnesium halide (or aryllthium) with appropriate aryl(dialkoxy)borane (4), heteroaryl(dialkoxy)borane or alkyl(dialkoxy)borane (alkoxy group comprised of methoxy, ethoxy, isopropoxy, or propoxy moiety), followed by acidic hydrolysis affords the unsymmetrical borinic acids 6 in excellent yields.

Where applicable, the reaction of the alkylene esters (3, T = nothing, CH,,

CMe.) with the appropriate organolithium or organomagnesium reactant is convenient.

As shown in Scheme 1, the borinic acid complexes are obtained from the precursor borinic acids by reaction with 1 equivalent of the desired heterocyclic ligand in suitable solvents (i.e., ethanol, isopropanol, dioxane, ether, toluene, dimethylformamide, N-methylpyrrolidone, or tetrahydrofuran).

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In certain situations, compounds of the invention may contain one or more asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms. These compounds can be, for example, racemates or optically active forms. In these situations, the single enantiomers, i.e., optically active forms, can be obtained by asymmetric synthesis or by resolution of the racemates. Resolution of the racemates can be ‘accomplished, for example, by conventional methods such as crystallization in the presence of a resolving agent, or chromatography, using, for example a chiral HPLC column.

Representative compounds of the present invention include, but are not limited to the compounds disclosed herein and their pharmaceutically acceptable acid and base addition salts. In addition, if the compound of the invention is obtained as an acid addition salt, the free base can be obtained by basifying a solution of the acid salt. Conversely, if the product is a free base, an addition salt, particularly a pharmaceutically acceptable addition salt, may be produced by dissolving the free base in a suitable organic solvent and treating the solution with an acid, in accordance with conventional procedures for preparing acid addition salts from base compounds. In a preferred embodiment, the compounds of the invention comprise any of compounds 10 - 123 (Tables 1, 2, 3 and 4), and variants thereof.

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Claims (8)

WHAT IS CLAIMED IS:

1. A method of synthesizing a borinic acid, said method comprising: a) contacting a R*-containing boronic acid with an organolithium or organomagnesium R**-containing compound under conditions sufficient to produce said borinic acid; wherein R* and R** are each independently selected from substituted or unsubstituted alkyl (C, - Cy), substituted or unsubstituted cycloalkyl (Cs - Cs), substituted or unsubstituted vinyl, substituted or unsubstituted alkynyl, substituted or unsubstituted benzyl, substituted or unsubstituted phenyl, and substituted or unsubstituted heterocycle, the two oxygen atoms which are covalently attached to the boron atom in said R*-containing boronic acid are additionally covalently attached, either directly or through a linker, thereby synthesizing said borinic acid.

2. The method of claim 1, wherein said R* and R** are different.

3. The method of claim 1, wherein said oxygen atoms are covalently attached through a linker and said linker is substituted or unsubstituted alkyl.

4. The method of claim 3, wherein said linker is a member selected from ethylene, propylene and 2,2 dimethyl propylene.

5. The method of claim 1, further comprising: b) synthesizing said R*-containing boronic acid.

6. The method of claim 5, further comprising: c) after step b), purifying said R*-containing boronic acid.

7. The method of claim 1, further comprising: 4? AMENDED SHEET 13.06.2006 d) subjecting the product of step a) to acidic hydrolysis conditions.

8. The method of claim 1, wherein said R* and R** are members independently selected from phenyl, cyanophenyl, thienyl, halophenyl, chlorofluorophenyl, methylhalophenyl, vinyl, ethynyl, cyclopropyl, methyl, and pyridyl. 43 AMENDED SHEET 13.06.2006