US 2003005.5090A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2003/0055090 A1 Lin et al. (43) Pub. Date: Mar. 20, 2003

(54) ANTIVESICANT COMPOUNDS AND (52) U.S. Cl...... 514/345; 546/290 METHODS OF MAKING AND USING THEREOF (57) ABSTRACT (76) Inventors: Ai J. Lin, North Potomac, MD (US); Michael C. Babin, Bel Air, MD (US) AS disclosed herein, the present invention provides a com Correspondence Address: pound having the Structural formula Office of the Staff Judge Advocate U.S. Army Medical Research and Materiel Command R2 R1 ATTN: MCMR-JA (Ms. Elizabeth Arwine) 504 Scott Street / \ Fort Detrick, MD 21702-5012 (US) R3 SH (21) Appl. No.: 10/172,074 N R4 O (22) Filed: Jun. 17, 2002 Related U.S. Application Data wherein R', R, R, and R" are each independently H, or a (62) Division of application No. 09/911,520, filed on Jul. methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy 25, 2001, now abandoned. group, or a pharmaceutically acceptable Salt or prodrug s s thereof. Also disclosed are compounds, compositions, meth Publication Classification ods and kits for treating, preventing, or inhibiting injuries induced by a vesicant agent, Such as bis-2-chloroethylsulfide (51) Int. Cl." ...... C07D 213/63; A61K 31/44; (HD). Additionally, protectants and decontaminants are dis CO7D 213/70 closed. US 2003/0055090 A1 Mar. 20, 2003

ANTIVESCANT COMPOUNDS AND METHODS Rev. 135-142; and Dannenberg, Jr., A. M. et al. (1991) OF MAKING AND USING THEREOF Proceed. 1991 Med. Defense BioSci. Rev. 147-150. 0008. Other approaches are based on compounds which ACKNOWLEDGMENT OF GOVERNMENT possess Strong nucleophilicity and react rapidly with HD to SUPPORT produce non-invasive products. See Ogston, A. G., et al. 0001. This invention was made by employees of the (1948) Trans. Fara. Soc. 44:45. For example, sulfur con United States Army. The government has rights in the taining chemicals, Such as cysteine, glutathione and 2-mer invention. captoethylamines have been shown to protect cells from HD toxicity in experimental animals. See Walker, I. G., et al. BACKGROUND OF THE INVENTION (1969) Canadian J. Physiol. Pharmacol. 47(2):143-51. These mercapto compounds protect the cell by interacting with HD 0002) 1. Field of the Invention to form non-reactive Sulfides. The practical values of the above mentioned Sulfur compounds, however, are impaired 0003. This invention relates generally to antivesicant by either poor passage of the drugs acroSS the cell mem compounds and methods of making and using thereof. In brane, easy oxidation to form inactive disulfide or their poor particular, the present invention relates to antivesicant com nucleophilicity. It has been shown that sulfide anions (RS) pounds comprising 2-mercaptopyridine-N-oxide as a back are much stronger nucleophiles than the free thiols (RSH). bone structure. See Reid, E. E.: ORGANIC CHEMISTRY OF BIVALENT 0004 2. Description of the Related Art SULFUR, Vol. II. Chapt. 5, 237-288, Chemical Publishing Co., Inc., New York, N.Y. (1960); and Quayle, O. R. et al. 0005 Vesicants are chemical warfare agents which cause (1942) J. Amer. Chem. Soc. 64:226-230. For example, blisters and include Sulfur mustard, nitrogen mustard, sodium thiophenol (PhSNa) reacts with n-butylbromide one Lewisite, and phosgene oXime. Bis-2-chloroethylsulfide thousand times faster than thiophenol (PhSH). Since the (HD) is a radiomimetic alkylating agent that has mutagenic, aliphatic thiols, Such as cysteine and glutathione, do not cytotoxic, and carcinogenic properties. See Auerbach, C, et ionize in physiological pH, their nucleophilicity are weak al. (1946) Nature 157:302; Wheller, G. P. (1962) Cancer under physiological conditions and thus have limited poten Res. 22:651-688; and Heston, W. E. (1950) J. Natl. Cancer. tial as a Scavenger of HD. Inst. 11:415-423. In the battlefield, HD has been used as a chemical weapon which produces incapacitating blistering 0009. Despite all the research and various approaches, injuries at the site of exposure. See Columbine, H. (1947) the biochemical mechanism of HD-induced injury is still not Nature 159:151-153; Papirmeister, B., et al. (1984) J. Cut. fully understood and no effective treatment for HD-induced and Ocular Toxicol. 3:371-393; and Vogt, R. F. et al. (1984) injury is available. Thus, a need still exists for effective Fundam. Appl. Toxicol. 4(2):571-583. treatments for HD-induced injuries. 0006 Biochemical studies on cells exposed to HD indi SUMMARY OF THE INVENTION cate that DNA alkylation is the primary lesion which leads to a Series of biochemical changes, including depurination of 0010. The present invention generally relates to a com DNA strands, DNA break, activation of chromosomal pound having the Structural formula enzyme poly(ADP-ribose)polymerase, depletion of cofactor NAD", inhibition of glycolysis, elevation of protease activ ity and finally blister formation. See Papirmeister, B., et al. R2 R1 (1985) Fundam. Appl. Toxicol. 5:S134. Chemically, HD first forms a reactive Sulfonium intermediate which then reacts randomly with macromolecules, such as DNA, RNA and R-/ Y-sh protein. See Walker, I. G., et al. (1969) Canadian J. Physiol. N+ Pharmacol. 47(2): 143-151; and Ogston, A. G., et al. (1948) V Trans. Fara. Soc. 44:45. The alkylation of DNA is what R4 O causes the drastic biochemical changes and blister forma tion. The site of alkylation on DNA is found to be the N7 of 0.011 wherein R', R, R, and R' are each independently purine bases, particularly guanidine. H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or 0007 Various approaches have been attempted in order to acyloxy group, or a pharmaceutically acceptable Salt or find therapeutic compounds which prevent blister formation prodrug thereof. In Some embodiments, two adjacent R caused by HD exposure. For example, the examination of Substituents may form a cycloalkyl, heterocycloalkyl, aryl, poly(ADP-ribose)polymerase or protease as potential target or heteroaryl group. In Some preferred embodiments, R', R, enzymes have been emphasized in recent years. See Purnell, R and R" are each independently H, methyl, methoxy, M. R., et al. (1980) Biochem. J. 185:775; Sestili, P., et al. chloro, fluoro, or bromo. In Some preferred embodiments, (1988) Pharm. Res. Comm. 20:613; Rankin, P. W., et al. the compound is 2-mercaptopyridine-N-oxide, 4-methyl-2- (1989) J. Biol. Chem. 264:4312; Powers, J. C., et al. (1991) mercaptopyridine-N-oxide, 6-methyl-2-mercaptopyridine Proceed. 1991 Med. Defense Biosci. Rev. 41-48; and N-oxide, 4,6-dimethyl-2-mercaptopyridine-N-oxide, Cowan, F. M., et al. (1991) Proceed. 1991 Med. Defense 5-bromo-2-mercaptopyridine-N-oxide, 5-methyl-2-mercap Biosci. Rev. 155-158. Inhibitors of these two enzymes have topyridine-N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, been shown to decrease the toxicity of HD. See Clayson, E. 5-chloro-2-mercaptopyridine-N-oxide, 4-chloro-2-mercap T., et al. (1991) Proceed. 1991 Med. Defense Biosci. Rev. topyridine-N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyri 127-130; Meiers, H. L. Proceed. 1991 Med. Defense Biosci. dine-N-oxide, 5-trifluoromethyl-2-mercaptopyridine-N-ox US 2003/0055090 A1 Mar. 20, 2003 ide, 2-mercaptoquinoline-N-oxide, or a pharmaceutically mercaptopyridine-N-oxide, 4,6-dimethyl-2-mercaptopyri acceptable Salt or prodrug thereof. In Some embodiments, dine-N-oxide, 5-bromo-2-mercaptopyridine-N-oxide, the compound is an antivesicant. 5-methyl-2-mercaptopyridine-N-oxide, 3-chloro-2-mercap topyridine-N-oxide, 5-chloro-2-mercaptopyridine-N-oxide, 0012. In some embodiments, the present invention pro 4-chloro-2-mercaptopyridine-N-oxide, 3,4,5, or 6-methoxy vides a pharmaceutical composition comprising a compound 2-mercaptopyridine-N-oxide, 5-trifluoromethyl-2-mercap having the Structural formula topyridine-N-oxide, or 2-mercaptoquinoline-N-oxide. The protectant or decontaminant may be clothing, combat gear, R2 R1 a protective shelter, a weapon, a piece of equipment, a filter, a Sponge, a foam, a Spray, a lotion, or a gas. The protectant or decontaminant may be used to prevent exposure of a R-( Y-sh Subject to a vesicant agent. The protectant may be used to N+ treat a Subject exposed to a vesicant agent or treat an injury V induced by a vesicant agent. The decontaminant may be R4 O used to decontaminate a Subject or an object exposed to a vesicant agent. In Some embodiments, the protectant or decontaminant further comprises a Second antivesicant com 0013 wherein R', R, R, and Rare each independently pound, a Supplementary active compound, or both. In Some H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or embodiments, the present invention provides a kit compris acyloxy group, or a pharmaceutically acceptable Salt or ing the protectant or decontaminant and instructions for use. prodrug thereof, and a pharmaceutically acceptable excipi ent. In Some embodiments, two adjacent R Substituents may 0016. In some embodiments, the present invention pro form a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl vides a method of treating, preventing, or inhibiting an group. In some preferred embodiments, R', R, R, and R' injury induced by a vesicant agent comprising administering are each independently H, methyl, methoxy, chloro, fluoro, at least one compound having the Structural formula or bromo. In Some embodiments, the compound is 2-mer captopyridine-N-oxide, 4-methyl-2-mercaptopyridine-N- oxide, 6-methyl-2-mercaptopyridine-N-oxide, 4,6-dim R2 R1 ethyl-2-mercaptopyridine-N-oxide, 5-bromo-2- mercaptopyridine-N-oxide, 5-methyl-2-mercaptopyridine N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, 5-chloro-2- R-( Y-sh mercaptopyridine-N-oxide, 4-chloro-2-mercaptopyridine N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyridine-N-oxide, V 5-trifluoromethyl-2-mercaptopyridine-N-oxide, 2-mercap R4 O toquinoline-N-oxide, or a pharmaceutically acceptable Salt or prodrug thereof. In Some embodiments, the pharmaceu tical composition further comprises a Second antivesicant 0017 wherein R, R, R, and R' are each independently compound. In Some embodiments, the pharmaceutical com H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or position further comprises a Supplementary active com acyloxy group, or a pharmaceutically acceptable Salt or prodrug thereof to a Subject. Two adjacent R Substituents pound Such as an anti-inflammatory or an anti-protease drug may form a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl or compounds. group. In some preferred embodiments, R', R, R, and R' 0.014. In some embodiments, the present invention is are each independently H, methyl, methoxy, chloro, fluoro, directed to protectant or decontaminant comprising a com or bromo. In Some embodiments, the compound is 2-mer pound having the Structural formula captopyridine-N-oxide, 4-methyl-2-mercaptopyridine-N- oxide, 6-methyl-2-mercaptopyridine-N-oxide, 4,6-dim ethyl-2-mercaptopyridine-N-oxide, 5-bromo-2- R2 R1 mercaptopyridine-N-oxide, 5-methyl-2-mercaptopyridine N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, 5-chloro-2- mercaptopyridine-N-oxide, 4-chloro-2-mercaptopyridine R-( Y-sh N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyridine-N-oxide, N+ 5-trifluoromethyl-2-mercaptopyridine-N-oxide, 2-mercap V toquinoline-N-oxide, or a pharmaceutically acceptable Salt R4 O or prodrug thereof. In Some embodiments, the injury is an HD-induced injury. The compound may be administered before, during, after, or a combination thereof exposure to 0015 wherein R', R, R, and Rare each independently the vesicant agent. In Some embodiments, the method H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or includes administering a Second antivesicant compound, a acyloxy group. In Some embodiments, two adjacent R Supplementary active compound, or both to the Subject Substituents of the compound form a cycloalkyl, heterocy before, during, after or a combination thereof exposure to cloalkyl, aryl, or heteroaryl group. In preferred embodi the vesicant agent. The compound may be administered ments, R,R,R, and Rare each independently H, methyl, topically or Systemically. methoxy, chloro, fluoro, or bromo. In Some preferred embodiments, the compound is 2-mercaptopyridine-N-OX 0018. In some embodiments, the present invention relates ide, 4-methyl-2-mercaptopyridine-N-oxide, 6-methyl-2- to a method of decontaminating an area exposed to a US 2003/0055090 A1 Mar. 20, 2003

Vesicant agent comprising contacting a compound having toquinoline-N-oxide, or a pharmaceutically acceptable Salt the structural formula or prodrug thereof. In Some embodiments, the kit further comprises a Second antivesicant compound. In Some embodiments, the kit further comprises a Supplementary R2 R1 active compound Such as an anti-inflammatory or an anti protease drug or compound. R3 / \ SH 0022. In some embodiments, the present invention is N+ directed to a kit for decontaminating an area exposed to a V vesicant agent comprising at least one compound having the R4 O Structural formula

0019 wherein R,R,R, and R' are each independently R2 R1 H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy group with the area. Two adjacent R Substituents may form a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl R-/ Y-sh group. In some preferred embodiments, R', R, R, and R' N+ are each independently H, methyl, methoxy, chloro, fluoro, V or bromo. In Some embodiments, the compound is 2-mer R4 O captopyridine-N-oxide, 4-methyl-2-mercaptopyridine-N- oxide, 6-methyl-2-mercaptopyridine-N-oxide, 4,6-dim ethyl-2-mercaptopyridine-N-oxide, 5-bromo-2- 0023 wherein R, R, R, and R' are each independently mercaptopyridine-N-oxide, 5-methyl-2-mercaptopyridine H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, 5-chloro-2- acyloxy group and instructions for use. In Some embodi mercaptopyridine-N-oxide, 4-chloro-2-mercaptopyridine ments, two adjacent R Substituents of the compound may N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyridine-N-oxide, form a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl 5-trifluoromethyl-2-mercaptopyridine-N-oxide, or 2-mer group. In some preferred embodiments, R', R, R, and R' captoquinoline-N-oxide. In Some embodiments, the vesicant are each independently H, methyl, methoxy, chloro, fluoro, agent comprises HD. In Some embodiments, a Second anti or bromo. In Some embodiments, the compound is 2-mer vesicant compound, a Supplementary active compound, or captopyridine-N-oxide, 4-methyl-2-mercaptopyridine-N- both may be applied to the area exposed to the vesicant oxide, 6-methyl-2-mercaptopyridine-N-oxide, 4,6-dim agent. ethyl-2-mercaptopyridine-N-oxide, 5-bromo-2- mercaptopyridine-N-oxide, 5-methyl-2-mercaptopyridine 0020. In some embodiments, the present invention pro N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, 5-chloro-2- vides a kit for treating, preventing, or inhibiting an injury mercaptopyridine-N-oxide, 4-chloro-2-mercaptopyridine induced by a vesicant agent comprising at least one com N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyridine-N-oxide, pound having the Structural formula 5-trifluoromethyl-2-mercaptopyridine-N-oxide, or 2-mer captoquinoline-N-oxide. In Some embodiments, the kit fur ther comprises a Second antivesicant compound. R2 R1 0024. It is to be understood that both the general descrip tion and the detailed description herein are exemplary only R-/ Y-sh and are intended to illustrate several embodiments of the N+ invention, explain the principles of the invention, and pro V R4 O vide further explanation of the invention as claimed. DETAILED DESCRIPTION OF THE 0021 wherein R,R,R, and R' are each independently INVENTION H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or 0025 Generally, the present invention provides 2-mer acyloxy group, or a pharmaceutically acceptable Salt or captopyridine-N-oxide compounds for treating, preventing, prodrug thereof and instructions for use. In Some embodi or inhibiting injuries induced by vesicant agents which ments, two adjacent R Substituents of the compound may includes sulfur mustard (bis-2-chloroethylsulfide (HD)), form a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl Nitrogen mustard (Mustargen 7), Lewisite, phosgene oxime, group. In some preferred embodiments, R', R, R, and R' and combinations thereof. Preferably, the present invention are each independently H, methyl, methoxy, chloro, fluoro, provides 2-mercaptopyridine-N-oxide compounds for treat or bromo. In Some embodiments, the compound is 2-mer ing, preventing, or inhibiting bis-2-chloroethylsulfide (HD) captopyridine-N-oxide, 4-methyl-2-mercaptopyridine-N- induced injuries. oxide, 6-methyl-2-mercaptopyridine-N-oxide, 4,6-dim ethyl-2-mercaptopyridine-N-oxide, 5-bromo-2- 0026, 2-mercaptopyridine-N-oxide compounds having mercaptopyridine-N-oxide, 5-methyl-2-mercaptopyridine various Substituents on the pyridine ring were designed and N-oxide, 3-chloro-2-mercaptopyridine-N-oxide, 5-chloro-2- Synthesized initially as pretreatment antidotes of HD. AS mercaptopyridine-N-oxide, 4-chloro-2-mercaptopyridine shown below in the Schematic rational, a thiol 1 with proper N-oxide, 3,4,5, or 6-methoxy-2-mercaptopyridine-N-oxide, pKa is expected to ionize under physiological pH to generate 5-trifluoromethyl-2-mercaptopyridine-N-oxide, 2-mercap a thiol anion 2. US 2003/0055090 A1 Mar. 20, 2003

Rationale

R R R sasÁs Ionization sasÁs R-SCHCHCI sasÁs He- Ho 2 in vivo 2 vesicant 2 st 's- O O O CH2CH2SR' 1. 2 3

R'- SCH2CH2OH -N Mo 5

SA Relative Nucleophilicity S- SBu 2 N S

O CH2CH2SR 1OOO Cl-, Butyl Bromide He 4 O- OBu

0027. The thiol anion 2 is a potent nucleophile which 0029 Sandmeyer reaction of substituted 2-aminopyri reacts rapidly with HD to form an inactive adduct 3. The dine 6 gave the corresponding 2-bromo-derivatives 7. The N-oxide function in the inactive adduct 3 is also a Strong N-oxidation of 7 was achieved by treatment of the pyridine nucleophile which can either Scavenge another molecule of ring with m-chloroperbenzoic acid to give the pyridine HD or serve as an internal base to catalyze the hydrolysis of N-oxide 8. Heating of compound 8 with NaSH acqueous the Sulfide bond, via transitional intermediate 4, to regener Solution gave the final products, Substituted 2-mercaptopy ate the thiol anion 2 and a non-toxic alcohol 5. Therefore, ridine-N-oxides 9. This procedure was successfully thiols 1 may serve as a catalyst to facilitate the hydrolysis of employed to prepare 3-methyl, 4-methyl, 5-methyl-, HD in vivo. 5-chloro-, 3-chloro-, 4-chloro-, and 5-bromo-2-mercaptopy ridine-N-oxide in yields ranging from about 45% to about 0028. The 2-mercaptopyridine-N-oxide compounds were 90%. prepared according to the following Scheme. 0030 The antivesicant activities of these 2-mercaptopy ridine-N-oxide compounds were assessed by the Mouse Ear Antivesicant Drug Screening Assay Protocol of Institute of m-chloroperbenzoic NaNO2 N acid Chemical Defense (ICD) as disclosed in Example 1. For the --- -- pre-treatment experiments, given concentrations, based on HBr/Br 2 toxicity expectations, limits of Solubility, or both, of the test N NH2 N Br compounds were applied to one side of the mouse ear 15 6 7 minutes prior to the HD exposure. For the treatment experi R R ments, various concentrations of the test compounds were applied to one side of the mouse ear at Specific times after f N NaSH N the HD exposure. The antivesicant activities of the 2-mer 2 2 captopyridine-N-oxide compounds were measured by the N Br N SH percentage ear weight reduction of the treated ear versus the O O untreated control ear weight of the same mouse. The results 8 9 are shown in Table 1 at Example 1. R = H, 3-Me, 4-Me, 5-Me, 6-Me, 3-Cl, 4-CI, 5-C1, and 5-Br 0031 Out of the 9 compounds tested, only 3 compounds, 2-mercaptopyridine-N-oxide, 4-methyl-2-mercaptopyri dine-N-oxide, and 6-methyl-2-mercaptopyridine-N-oxide, US 2003/0055090 A1 Mar. 20, 2003 showed significant antivesicant activity. AS used herein, “significant antiveSicant activity” means greater than about 20% relative ear weight (REW) reduction from the positive HD control ear. 4-Methyl- derivatives showed Superior / Y sh antivesicant activity over the 6-methyl analogs in both 15 N+ minutes pre-exposure (about 57% vs. about 42%) and 10 V minutes post-exposure experiments (about 68% vs. about O 36%). However, the 6-methyl analog showed better protec 1-Oxy-5,6,7,8-tetrahydro-quinoline-2-thiol tive efficacy when applied 20 minutes after the HD exposure than the 4-methyl analog (about 25% vs. about 11%), and / y st exhibited Significant protective activity even 60 minutes N+ after HD exposure. AS shown in the ten minutes post V exposure assay, unsubstituted 2-mercaptopyridine-N-oxide O is as active as the 6-methyl-analog, but leSS active than the 2-mercaptoquinoline-N-oxide 4-methyl-analog. While 4-methyl and 6-methyl substituted / y st 2-mercaptopyridine-N-oxides demonstrated Strong antivesi and cant activity, the 3-methyl and 5-methyl analogs exhibited N+ V no Statistical significant reduction in relative ear weight O (REW) from the positive HD control ear. 1-Oxy-6, 7-dihydro-5H-1pyrindine -2-thiol 0.032 The results indicated that the nucleophilicity of pyridine-N-oxide relates to the efficacy of the compound as an antivesicant. Since a methyl group at 4 or 6 position of / \, st the pyridine ring is an efficient electron donor which N+ V enhanced the nucleophilicity of the N-oxide group and thus O potentiated the Scavenging activity of the molecule. The 3-Oxy-3-aza-bicyclo[4.2.0 octa-1(6),2,4-triene-4-thiol chloro or bromo function at 3 or 5 position are electron withdrawing groups which decreased the nucleophilicity of the N-oxide and the SH group, thus failed in the antivesicant 0036 Preferred compounds include 4-methyl and 6-me teStS. thyl substituted 2-mercaptopyridine-N-oxides. Preferred 0.033 Since the N-oxide function is the reactive site, the compounds include: methyl group at 6-position of the pyridine ring created a Steric hindrance to the reactive site, which may explain why the 6-methyl-2-mercaptopyridine-N-oxide is less active than the 4-methyl-2-mercaptopyridine-N-oxide. / Y sh 0034. Thus, the present invention relates to compounds V comprising the following following Structural Formula A, O which comprises 2-mercaptopyridine-N-oxide as a back 2-mercaptopyridune-N-oxide bone:

and R2 R1 N+ V O R-( Y-sh 4-methyl-2-mercaptopyridine-N-oxide N+ V R4 O N+ V 0035) wherein R', R, R, and Rare each independently O H, methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy, 6-methyl-2-mercaptopyridine-N-oxide preferably, R', R, R, and R" are each independently H, methyl, methoxy, chloro, fluoro, or bromo, more preferably, R", R, R, and R" are each independently H, methyl, 0037. The present invention also provides methods of methoxy, chloro, or bromo. In Some preferred embodiments, treating, preventing, or inhibiting an injury induced by a R, R", or both, are a substituent other than H. In some vesicant agent, Such as an HD-induced injury, comprising preferred embodiments, two adjacent R group Substituents administering at least one compound comprising the follow form a ring Structure which shares a bond with the pyridine ing Structural Formula A, which comprises 2-mercaptopy ring to give a compound Such as ridine-N-oxide as a backbone: US 2003/0055090 A1 Mar. 20, 2003

mustard (Mustargen 7), Lewisite, phosgene oxime, and com binations thereof. As used herein, “HD-induced injuries” are R2 R1 injuries caused by exposure to HD compounds and combi nations comprising HD such as HD Lewisite (HL). Such antivesicant and HD induced injuries include damage to R-/ Y-sh skin, eyes, lungs, including upper and lower airways, and N+ Systemic effects Such as bone marrow Suppression. V R4 O 0044 As used herein, “antivesicant activity” refers to the activity of a compound which prevents, inhibits or modu lates an injury induced by a vesicant agent. 0038 wherein R,R,R, and R' are each independently H, methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy, 0045. As used herein, “antivesicant” or “antivesicant preferably, R', R, R, and R" are each independently H, compound” refers to a compound which exhibits antiveSi methyl, methoxy, chloro, fluoro, or bromo, more preferably, cant activity. R", R, R, and R" are each independently H, methyl, 0046. In accordance with a convention used in the art, % is methoxy, chloro, or bromo. In Some preferred embodiments, used in Structural formulas herein to depict the bond that is R, R", or both, are a substituent other than H. In some the point of attachment of the moiety or substituent to the preferred embodiments, two adjacent R group Substituents core or backbone structure. Additionally, bused in the Sche form a ring Structure which shares a bond with the pyridine matic rationale above is used to depict the bonds that are the ring. Preferred compounds include 4-methyl and 6-methyl point of attachment of either two Substituents, which may or Substituted 2-mercaptopyridine-N-oxides. may not be the same, or a ring structure. 0.039 The present invention also provides a protectant or 0047. Where chiral carbons are included in chemical decontaminant comprising at least one compound compris Structures, unless a particular orientation is depicted, both ing the following Structural Formula A, which comprises Sterioisomeric forms are intended to be encompassed. 2-mercaptopyridine-N-oxide as a backbone: 0048. An “alkyl group” is intended to mean a straight or branched chain monovalent radical of Saturated and/or unsaturated carbon atoms and hydrogen atoms, Such as R2 R1 methyl (Me), ethyl (Et), propyl (Pr), isopropyl (i-Pr), butyl (Bu), isobutyl (i-Bu), t-butyl (t-Bu), ethenyl, pentenyl, bute nyl, propenyl, ethynyl, butynyl, propynyl, pentynyl, hexy R-/ Y-sh nyl, and the like, which may be unsubstituted (i.e., contain only carbon and hydrogen) or Substituted by one or more V R4 O Suitable Sustituents as defined below (e.g., one or more halogen, such as F, Cl, Br, or I, with F and Cl being preferred). A "lower alkyl group” is intended to mean an 0040 wherein R', R, R, and Rare each independently alkyl group having from 1 to 8 carbon atoms in its chain. H, methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy, 0049. A “cycloalkyl group” is intended to mean a non preferably, R', R, R, and R" are each independently H, aromatic monovalent monocyclic, bicyclic, or tricyclic radi methyl, methoxy, chloro, fluoro, or bromo, more preferably, cal comprising 3-14 carbon ring atoms, each of which may R", R, R, and R" are each independently H, methyl, be Saturated or unsaturated, and which may be unsubstituted methoxy, chloro, or bromo. In Some preferred embodiments, or substituted by one or more suitable substituents as defined R, R", or both, are a substituent other than H. In some below, and to which may be fused one or more heterocy preferred embodiments, two adjacent R group Substituents cloalkyl groups, aryl groups, or heteroaryl groups, which form a ring Structure which shares a bond with the pyridine themselves may be unsubstituted or substituted by one or ring. Preferred compounds include 4-methyl and 6-methyl more Substituents. Illustrative examples of cycloalkyl substituted 2-mercaptopyridine-N-oxides. Preferably, the groups include the following moieties: protectant or decontaminant include 4-methyl and 6-methyl Substituted 2-mercaptopyridine-N-oxide compounds. 0041. The protectant or decontaminant include clothing, combat gear, protective shelters, weapons, equipment, fil ters, Sponges, foams, Sprays, lotions, gases and the like which may be used to protect against or prevent injuries < D. O. O. O. induced by vesicant agents or may be used to decontaminate perSons or objects exposed to Vesicant agents. 0042. The terms and abbreviations used in the instant disclosure have their normal meanings unless otherwise s At 19 designated. AS used in the present application, the following definitions apply:

0.043 AS used herein, “antivesicant induced injuries” s ... At include those caused by exposure to vesicant agents Such as sulfur mustard (bis-2-chloroethylsulfide (HD)), Nitrogen US 2003/0055090 A1 Mar. 20, 2003

0050. A "heterocycloalkyl group” is intended to mean a non-aromatic monovalent monocyclic, bicyclic, or tricyclic -continued radical, which is Saturated or unsaturated, comprising 3-18 ring members, which includes 1-5 heteroatoms Selected from nitrogen, oxygen, and Sulfur, where the radical is unsubstituted or substituted by one or more suitable Sub stituents as defined below, and to which may be fused one or more cycloalkyl groups, aryl groups, or heteroaryl groups, which themselves may be unsubstituted or Substi tuted by one or more suitable substituents. Illustrative 0052 A“heteroaryl group” is intended to mean an aro examples of heterocycloalkyl groups include the following matic monovalent monocyclic, bicyclic, or tricyclic radical moieties: comprising 4-18 ring members, including 1-5 heteroatoms Selected from nitrogen, oxygen, and Sulfur, which may be unsubstituted or substituted by one or more suitable Sub stituents as defined below, and to which may be fused one or more cycloalkyl groups, heterocycloalkyl groups, or aryl groups, which themselves may be unsubstituted or Substi tuted by one or more suitable substituents. Illustrative < Q. C. O. O. examples of heteroaryl groups include the following moi S ( ). A eties: Ot. O As (y. Cy Cy Cy (y. V / A, C () (5.S

N N |N, N| ||N, N s N s S N N&-N N S R N

At y 21 N2

0051. An “aryl group” is intended to mean an aromatic monovalent monocyclic, bicyclic, or tricyclic radical com prising 6, 10, 14, or 18 carbon ring members, which may be unsubstituted or substituted by one or more suitable Sub stituents as defined below, and to which may be fused one or more cycloalkyl groups, heterocycloalkyl groups, or heteroaryl groups, which themselves may be unsubstituted or substituted by one or more suitable substituents. Thus, the term “aryl group” includes a benzyl group (BZl). Illustrative examples of aryl groups include the following moieties:

0053 A“heterocycle” is intended to mean a heteroaryl or heterocycloalkyl group (each of which, as defined above, are optionally Substituted). 0054) The terms “aryl” (Ar) and “heteroaryl” refer to , and monocyclic and polycyclic unsaturated or aromatic ring Structures, with “aryl” referring to those that are carbocycles US 2003/0055090 A1 Mar. 20, 2003 and "heteroaryl” referring to those that are heterocycles. conjugate base of a strong acid can act as a leaving group. Examples of aromatic ring Structures include phenyl, naph Illustrative examples of Suitable leaving groups include, but thyl, 1,2,3,4-tetrahydronaphthyl, furyl, thienyl, pyrrolyl, are not limited to, -F, -Cl, -Br, alkyl chlorides, alkyl pyridyl, pyridinyl, pyrazolyl, imidazolyl, pyrazinyl, bromides, alkyl iodides, alkyl Sulfonates, alkyl benzene pyridaZinyl, 1,2,3-triazinyl, 1,2,4-oxadiazolyl, 1,3,4-oxadia Sulfonates, alkyl p-toluenesulfonates, alkyl methane Zolyl, 1-H-tetrazol-5-yl, indolyl, quinolinyl, benzofuranyl, Sulfonates, triflate, and any groups having a bisulfate, benzothiophenyl (thianaphthenyl), and the like. methyl Sulfate, or Sulfonate ion. 0055 An “acyl group” is intended to mean a-C(O)-R 0076 A“protecting group” is intended to refer to groups radical, where R is a Suitable Substituent as defined below. that protect one or more inherent functional group from premature reaction. Suitable protecting groups may be rou 0056. A “thioacyl group” is intended to mean a-C(S)- tinely selected by those skilled in the art in light of the R" radical, where R is a Suitable Substituent as defined functionality and particular chemistry used to construct the below. compound. Examples of Suitable protecting groups are 0057. A “sulfonyl group” is intended to mean a -SOR described, for example, in Greene and Wutz, Protecting radical, where R is a Suitable Substituent as defined below. Groups in Organic Synthesis, 2" edition, John Wiley and 0.058 A“hydroxy group” is intended to mean the radical Sons, New York, N.Y. (1991). -OH. 0077. The term “suitable organic moiety” is intended to mean any organic moiety recognizable, Such as by routine 0059 An “amino group” is intended to mean the radical testing, to those skilled in the art as not adversely affecting -NH. the inhibitory activity of the inventive compounds. Illustra 0060 An “alkylamino group” is intended to mean the tive examples of Suitable organic moieties include, but are radical -NHR, where R is an alkyl group. not limited to, hydroxyl groups, alkyl groups, OXO groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, 0061. A “dialkylamino group” is intended to mean the heteroaryl groups, acyl groups, Sulfonyl groups, mercapto radical-NR'R'', where R and R are each independently groups, alkylthio groups, alkoxy groups, carboxy groups, an alkyl group. amino groups, alkylamino groups, dialkylamino groups, 0.062 An “alkoxy group” is intended to mean the radical carbamoyl groups, arylthio groups, heteroarylthio groups, -OR", where R is an alkyl group. Exemplary alkoxy and the like. groups include methoxy, ethoxy, propoxy, and the like. 0078. In general, the various moieties or functional 0.063 An “alkoxycarbonyl group” is intended to mean the groups for variables in the formulae may be “optionally radical-C(O)OR", where R is an alkyl group. substituted” by one or more suitable “substituents”. The term “Substituent” or "suitable Substituent” is intended to 0064. An “alkylsulfonyl group” is intended to mean the mean any Suitable Substituent that may be recognized or radical -SOR", where R is an alkyl group. Selected, Such as through routine testing, by those skilled in 0065. An “alkylaminocarbonyl group” is intended to the art. Illustrative examples of useful Substituents are those mean the radical-C(O)NHR', where R is an alkyl group. found in the exemplary compounds that follow, as well as halogen (chloro, iodo, bromo, or fluoro), C6-alkyl, C 0.066. A “dialkylaminocarbonyl group” is intended to alkenyl, C-alkynyl; hydroxyl, Calkoxyl, amino; nitro, mean the radical-C(O)NR'R'', where R and R are each thiol; thioether, imine, cyano; amido; phosphonato; phos independently an alkyl group. phine; carboxyl, carbonyl, aminocarbonyl; thiocarbonyl, 0067 A“mercapto group' is intended to mean the radical Sulfonyl, Sulfonamine, Sulfonamide, ketone, aldehyde, ester; -SH. oxygen (=O); haloalkyl (e.g., trifluoromethyl); carbocyclic cycloalkyl, which may be monocyclic or fused or non-fused 0068 An “alkylthio group” is intended to mean the polycyclic (e.g., cyclopropyl, cyclobutyl, cyclopentyl, or radical - SR", where R is an alkyl group. cyclohexyl), or a heterocycloalkyl, which may be monocy 0069. A “carboxy group” is intended to mean the radical clic or fused or non-fused polycyclic (e.g., pyrrolidinyl, -C(O)OH. piperidinyl, piperazinyl, morpholinyl, or thiazinyl); car bocyclic or heterocyclic, monocyclic or fused or non-fused 0070 A “carbamoyl group” is intended to mean the polycyclic aryl (e.g., phenyl, naphthyl, pyrrolyl, indolyl, radical-C(O)NH. furanyl, thiophenyl, imidazolyl, oxazolyl, isoxazolyl, thiaz 0071 An “aryloxy group” is intended to mean the radical olyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, quinolinyl, -OR, where R is an aryl group. isoquinolinyl, acridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, benzimidazolyl, benzothiophenyl, or benzofuranyl); amino 0.072 A "heteroaryloxy group” is intended to mean the (primary, Secondary, or tertiary), nitro; thiol; thioether, radical -OR, where R is a heteroaryl group. O-lower alkyl; O-aryl, aryl; aryl-lower alkyl, COCH; 0073. An “arylthio group” is intended to mean the radical CONH; OCHCONH; NH; SONH; OCHF; CF; -SR, where R is an aryl group. OCF; and the like. Such moieties may also be optionally Substituted by a fused-ring Structure or bridge, for example 0.074. A "heteroarylthio group” is intended to mean the OCH-O. All of these substituents may optionally be radical-SR, where R is a heteroaryl group. further substituted with a substituent selected from groups 0075) A “leaving group” (Lv) is intended to mean any Such as hydroxy groups, halogens, OXO groups, alkyl groups, Suitable group that will be displaced by a Substitution acyl groups, Sulfonyl groups, mercapto groups, alkylthio reaction. One of ordinary skill in the art will know that any groups, alkyloxy groups, cycloalkyl groups, heterocy US 2003/0055090 A1 Mar. 20, 2003 cloalkyl groups, aryl groups, heteroaryl groups, carboxy Structural formulas include compounds having the indicated groups, amino groups, alkylamino groups, dialkylamino Structure, including the hydrated as well as the non-hydrated groups, carbamoyl groups, aryloxy groups, heteroaryloxy forms. groups, arylthio groups, heteroarylthio groups, and the like. 0085. As indicated above, the compounds of the inven 007.9 The term “optionally substituted” is intended to tion also include active tautomeric and Stereoisomeric forms expressly indicate that the Specified group is unsubstituted or of the antivesicant compounds of the Structural Formula A, Substituted by one or more Suitable Substituents, unless the which may be readily obtained using techniques known in optional Substituents are expressly Specified, in which case the art. For example, optically active (R) and (S) isomers the term indicates that the group is unsubstituted or Substi may be prepared via a Stereospecific Synthesis, e.g., using tuted with the specified substituents. As defined above, chiral Synthons and chiral reagents, or racemic mixtures may various groups may be unsubstituted or Substituted (i.e., they be resolved using conventional techniques. are optionally Substituted) unless indicated otherwise herein 0086 The antivesicant compounds of the present inven (e.g., by indicating that the Specified group is unsubstituted). tion may be prepared using reaction routes, Synthesis 0080. It is understood that while a compound of the Schemes and techniques available in the art using Starting general Structural formulas herein may exhibit the phenom materials that are readily available. The antivesicant com enon of tautomerism, the Structural formulas within this pounds of the present invention were made according to the Specification expressly depict only one of the possible following schemes and methods. However, it should be tautomeric forms. It is therefore to be understood that the noted that the antivesicant compounds of the present inven Structural formulas herein are intended to represent any tion may be made by other methods known in the art. tautomeric form of the depicted compound and is not to be 0087 Substituted 2-Bromopyridine-N-oxide 8 was pre limited merely to a specific compound form depicted by the pared by the following procedure: 4-methyl-2-bromopyri Structural formulas. dine (5g, 29 mmol) was dissolved in 30 ml of chloroform. To the solution was added 80% m-chloroperbenzoic acid (7 0081. It is also understood that the structural formulas are g, 35 mmol). The mixture was stirred at room temperature intended to represent any configurational form of the for 4 days, filtered and the precipitate was washed with depicted compound and is not to be limited merely to a chloroform. The chloroform filtrate and the washings were Specific compound form depicted by the Structural formulas. combined, and then extracted 3 times with 20% HCl. The 0082 Some of the antivesicants may exist as single HCl extracts were combined and evaporated to dryneSS Stereoisomers (i.e., essentially free of other Stereoisomers), under reduced pressure. The residue was recrystallized from racemates, or mixtures of enantiomers, diastereomers, or EtOH and ether to give 3 grams (about 55%) of white both. All Such Single Stereoisomers, racemates and mixtures crystals 4-methyl-2-bromopyridine-N-oxide as HCl salts thereof are intended to be within the scope of the present which was converted to free N-oxide before use for the next invention. Preferably, the inventive compounds that are reaction. optically active are used in optically pure form. 0088. This same procedure was used to prepare 2-bromo 0.083 AS generally understood by those skilled in the art, 6-methylpyridine-N-oxide (about 53%), 2,5-dibromopyri an optically pure compound having one chiral center (i.e., dine-N-oxide (about 50%), 5-methyl-2-bromopyridine-N- one asymmetric carbon atom) is one that consists essentially oxide (about 90%), 2,3-dichloropyridine-N-oxide (about of one of the two possible enantiomers (i.e., is enantiomeri 45%), 5-chloro-2-bromopyridine-N-oxide (about 55%) and cally pure), and an optically pure compound having more 4-chloro-2-brompyridine-N-oxide (about 65%) from than one chiral center is one that is both diastereomerically 2-bromo-6-methylpyridine, 2,5-dibromopyridine, 5-methyl pure and enantiomerically pure. Preferably, if the com 2-bromopyridine, 2,3-dichloropyridine, 5-chloro-2-bro pounds of the present invention are made Synthetically, they mopyridine, and 4-chloro-2-brompyridine, respectively. The are used in a form that is at least 90% optically pure, that is, identity of these intermediate N-oxides were determined by a form that comprises at least 90% of a single isomer (80% NMR spectra. enantiomeric excess (e.e.) or diastereomeric excess (d.e.), 0089. Substituted 2-Mercaptopyridine-N-oxide 9 was more preferably at least 95% (90% e.e. or d.e.), even more prepared by the following procedure: 4-Methyl-2-bromopy preferably at least 97.5% (95% e.e. or de...), and most ridine-N-oxide (1.7 g., 0.01 mol) and NaHS (1.12 g, 0.02 preferably at least 99% (98% e.e. or de...). mol) in 10 ml of water was heated on a steam bath for 1.5 hours. The precipitate was removed. The filtrate was acidi 0084. Additionally, the structural formulas herein are fied with 6NHCl. The product was collected and recrystal intended to cover, where applicable, Solvated as well as lized from EtOAc to give light brown color crystals (0.8 g. unsolvated forms of the compounds. A “solvate” is intended to mean a pharmaceutically acceptable Solvate form of a about 50%), mp about 62 to about 64 C. Anal. (CHNS). Specified compound that retains the biological effectiveness 0090 The analogs, 6-methyl-(mp about 54 to about 56 of Such compound. Examples of Solvates include com C), 5-bromo-(mp about 135 to about 137 C), 5-methyl-(mp pounds of the invention in combination with water, isopro about 107 to about 108 C), 3-chloro- (mp about 108 to about panol, ethanol, methanol, dimethyl Sulfoxide, ethyl acetate, 109 C), 5-chloro-(mp about 133 to about 135 C), and acetic acid, ethanolamine, or acetone. Also included are 4-chloro-2-mercaptopyridine (mp about 83 to about 85 C) miscible formulations of Solvate mixtures Such as a com were prepared by the same procedure Starting from the pound of the invention in combination with an acetone and corresponding 2-bromopyridine-N-oxides. All products ethanol mixture. In a preferred embodiment, the Solvate were identified by NMR and elemental analysis. includes a compound of the invention in combination with 0091 Additionally, the compounds of the invention about 20% ethanol and about 80% acetone. Thus, the include pharmaceutically acceptable Salts, multimeric US 2003/0055090 A1 Mar. 20, 2003

forms, prodrugs, active metabolites, precursors and Salts of and active metabolites of a compound may be identified Such metabolites of the antivesicant compounds of the using routine techniques known in the art. See, e.g., Berto Structural Formulas described herein. lini, G. et al., (1997) J.Med. Chem. 40:2011-2016; Shan, D. 0092. The term “pharmaceutically acceptable salts' et al., J. Pharm. Sci., 86(7):765-767; Bagshawe K., (1995) refers to Salt forms that are pharmacologically acceptable Drug Dev. Res. 34:220-230; Bodor, N., (1984) Advances in and Substantially non-toxic to the Subject being treated with Drug Res. 13:224-331; Bundgaard, H., Design of Prodrugs the compound of the invention. Pharmaceutically acceptable (Elsevier Press, 1985); and Larsen, I. K., Design and Appli Salts include conventional acid-addition Salts or base-addi cation of Prodrugs, Drug Design and Development (Krogs tion Salts formed from Suitable non-toxic organic or inor gaard-Larsen et al., eds., Harwood Academic Publishers, ganic acids or inorganic bases. Exemplary acid-addition 1991). Salts include those derived from inorganic acids Such as 0095. If the antivesicant compound is a base, the desired hydrochloric acid, hydrobromic acid, hydroiodic acid, Sul pharmaceutically acceptable Salt may be prepared by any furic acid, Sulfamic acid, phosphoric acid, and nitric acid, Suitable method available in the art, for example, treatment and those derived from organic acids Such as p-toluene of the free base with an inorganic acid, Such as hydrochloric Sulfonic acid, methaneSulfonic acid, ethane-disulfonic acid, acid, hydrobromic acid, Sulfuric acid, nitric acid, phosphoric isethionic acid, oxalic acid, p-bromophenylsulfonic acid, acid and the like, or with an organic acid, Such as acetic acid, carbonic acid, Succinic acid, citric acid, benzoic acid, 2-ac maleic acid, Succinic acid, mandelic acid, fumaric acid, etoxybenzoic acid, acetic acid, phenylacetic acid, propionic malonic acid, pyrvic acid, oxalic acid, glycolic acid, Sali acid, glycolic acid, Stearic acid, lactic acid, malic acid, cylic acid, a pyranosidyl acid, Such as glucuronic acid or tartaric acid, ascorbic acid, maleic acid, hydroxymaleic acid, galacturonic acid, an alpha-hydroxy acid, Such as citric acid glutamic acid, Salicylic acid, Sulfanilic acid, and fumaric or tartaric acid, an amino acid, Such as aspartic acid or acid. Exemplary base-addition Salts include those derived glutamic acid, an aromatic acid, Such as benzoic acid or from ammonium hydroxides (e.g., a quaternary ammonium cinnamic acid, a Sulfonic acid, Such as p-toluenesulfonic hydroxide Such as tetramethylammonium hydroxide), those acid or ethaneSulfonic acid, or the like. derived from inorganic baseS Such as alkali or alkaline 0096. If the antivesicant compound is an acid, the desired earth-metal (e.g., Sodium, potassium, lithium, calcium, or pharmaceutically acceptable Salt may be prepared by any magnesium) hydroxides, and those derived from non-toxic Suitable method, for example, treatment of the free acid with organic bases Such as basic amino acids. an inorganic or organic base, Such as an amine (primary, 0093. The term “multimer” refers to multivalent or mul Secondary or tertiary), an alkali metal hydroxide or alkaline timeric forms of active forms of the compounds of the earth metal hydroxide, or the like. Illustrative examples of invention. Such “multimers' may be made by linking or Suitable Salts include organic Salts derived from basic amino placing multiple copies of an active compound in close acids, Such as lysine and arginine, ammonia, primary, Sec proximity to each other, e.g., using a Scaffolding provided by ondary, and tertiary amines, and cyclic amines, Such as a carrier moiety. Multimers of various dimensions (i.e., piperidine, morpholine and piperazine, and inorganic Salts bearing varying numbers of copies of an active compound) derived from Sodium, calcium, potassium, magnesium, man may be tested to arrive at a multimer of optimum size with ganese, iron, copper, Zinc, aluminum and lithium. Preferred respect to receptor binding. Provision of Such multivalent amines and Salts thereof are those that are clinically accept forms of active receptor-binding compounds with optimal able, i.e. not too toxic in the Subject being treated. spacing between the receptor-binding moieties may enhance 0097. In the case of compounds that are solids, it is receptor binding. See, for example, Lee et al., (1984) Bio understood by those skilled in the art that the inventive chem. 23:4255. The artisan may control the multivalency compounds and Salts may exist in different crystal or poly and Spacing by Selection of a Suitable carrier moiety or linker morphic forms, all of which are intended to be within the units. Useful moieties include molecular Supports compris Scope of the present invention and Specified Structural for ing a multiplicity of functional groups that can be reacted mulas. with functional groups associated with the active com 0098. The antivesicant activity of the antivesicant com pounds of the invention. A variety of carrier moieties may be pounds of the present invention may be measured by any of used to build highly active multimers, including proteins the methods available to those skilled in the art, including in such as BSA (bovine serum albumin) or HSA, peptides such Vitro and in Vivo assays. Examples of Suitable assays for as pentapeptides, decapeptides, pentadecapeptides, and the activity measurements are provided herein. Properties of the like, as well as non-biological compounds Selected for their antivesicant compounds may be assessed, for example, by beneficial effects on absorbability, transport, and persistence using one or more of the assays Set out in the Examples within the target organism. Functional groups on the carrier below. Other pharmacological methods may also be used to moiety, Such as amino, Sulfhydryl, hydroxyl, and alkylamino determine the efficacy of the compounds as antivesicant groups, may be Selected to obtain Stable linkages to the compounds. compounds of the invention, optimal spacing between the 0099. The antivesicant compounds in accordance with immobilized compounds, and optimal biological properties. the present invention are useful in the treatment of antiveSi 0094) “A pharmaceutically acceptable prodrug” is a com cant induced injuries, preferably HD-induced injuries and pound that may be converted under physiological conditions the like. Such antivesicant and HD induced injuries include or by Solvolysis to the Specified compound or to a pharma cutaneous, ocular and pulmonary injuries Such as damage to ceutically acceptable Salt of Such compound. “A pharma skin, eyes, lungs, including upper and lower airways, and ceutically active metabolite' is intended to mean a pharma Systemic effects Such as bone marrow Suppression. cologically active product produced through metabolism in 0100. The antivesicant compounds of the present inven the body of a specified compound or salt thereof. Prodrugs tion may be used in combination with or as a Substitution for US 2003/0055090 A1 Mar. 20, 2003

treatments of the above conditions. For example, the anti ascertained by those skilled in the art using conventional vesicant compounds may also be used alone or in combi dosage-determination tests in View of the experimental data nation with a Supplementary active compound Such as for a given antivesicant compound. Administration of pro anti-inflammatory and anti-protease drugs and the like to drugs may be dosed at weight levels that are chemically treat, prevent or inhibit antivesicant induced injuries Such as equivalent to the weight levels of the fully active forms. HD-induced injuries associated with exposure to HD com 0106 The antivesicant compounds of the invention can pounds and derivatives. be incorporated into pharmaceutical compositions Suitable 0101. An antivesicant compound of the present invention for administration. Pharmaceutical compositions of this may be administered in a therapeutically effective amount to invention comprise a therapeutically effective amount of an a mammal Such as a human. A therapeutically effective antivesicant compound having the Structural Formula A, amount may be readily determined by Standard methods and an inert, pharmaceutically acceptable carrier or diluent. known in the art. AS used herein, a “therapeutically effective AS used herein the language “pharmaceutically acceptable amount of an antivesicant compound of the present inven carrier' is intended to include any and all Solvents, disper tion is an amount which prevents, inhibits, Suppresses or Sion media, coatings, antibacterial and antifungal agents, reduces the amount of injury or damage caused by exposure isotonic and absorption delaying agents, and the like, com to a vesicant agent, Such as an HD compound or derivative patible with pharmaceutical administration. The pharmaceu thereof, in a Subject as compared to a control. tical carrier employed may be either a Solid or liquid. Exemplary of Solid carriers are lactose, Sucrose, talc, gelatin, 0102) As defined herein, a therapeutically effective agar, pectin, acacia, magnesium Stearate, Stearic acid and the amount of a compound of the present invention may be like. Exemplary of liquid carriers are Syrup, peanut oil, olive readily determined by one of ordinary skill by routine oil, water and the like. Similarly, the carrier or diluent may methods known in the art. Preferred topical concentrations include time-delay or time-release material known in the art, include about 0.1% to about 10% in a formulated Salve. The Such as glyceryl monoStearate or glyceryl distearate alone or skilled artisan will appreciate that certain factors may influ with a wax, ethylcellulose, hydroxypropylmethylcellulose, ence the dosage required to effectively treat a Subject, methylmethacrylate and the like. The use of Such media and including but not limited to the Severity of the disease or agents for pharmaceutically active Substances is well known disorder, previous treatments, the general health and/or age in the art. of the Subject, and other diseases present. 0107 Except insofar as any conventional media or agent 0103 Moreover, treatment of a subject with a therapeu is incompatible with the active compound, use thereof in the tically effective amount of the antivesicant compound pref compositions is contemplated. Supplementary active com erably includes a single treatment, but can include a Series pounds can also be incorporated into the compositions. of treatments. For example, a Subject may be treated with an Supplementary active compounds include anti-inflamma antivesicant compound of the invention at least once. How tory and anti-protease drugs and other compounds com ever, the Subject may treated with the antivesicant com monly used to treat injuries induced by exposure to Vesicant pound from about one time per week to about Several times agents. daily for a given treatment period. The length of the treat ment period will depend on a variety of factorS Such as the 0108) A pharmaceutical composition of the invention is length of exposure to the vesicant agent, the Severity of the formulated to be compatible with its intended route of injury, the predisposition of exposure to a vesicant com administration. Examples of routes of administration include pound, or a combination thereof. It will also be appreciated parenteral, e.g., intravenous, intradermal, Subcutaneous, oral that the effective dosage of the compound used for treatment (e.g., inhalation), transdermal (topical), transmucosal, and may increase or decrease over the course of a particular rectal administration. Solutions or Suspensions used for treatment. Changes in dosage may result and become appar parenteral, intradermal, or Subcutaneous application can ent by Standard diagnostic assays known in the art. In Some include the following components: a Sterile diluent Such as instances chronic administration may be required. The anti water for injection, Saline Solution, fixed oils, polyethylene vesicant compound may be administered before, during, glycols, glycerine, propylene glycol or other Synthetic Sol after, or a combination thereof exposure to a vesicant agent. vents, antibacterial agents Such as benzyl alcohol or methyl parabens, antioxidants Such as ascorbic acid or Sodium 0104. The pharmaceutical compositions of the invention bisulfite, chelating agents Such as ethylenediaminetetraace may be prepared in a unit-dosage form appropriate for the tic acid; bufferS Such as acetates, citrates or phosphates and desired mode of administration. The compositions of the agents for the adjustment of tonicity Such as Sodium chloride present invention may be administered for therapy by any or dextrose. The pH can be adjusted with acids or bases, Such Suitable route including oral, rectal, nasal, topical (including as hydrochloric acid or Sodium hydroxide. The parenteral buccal and Sublingual), vaginal and parenteral (including preparation can be enclosed in ampoules, disposable Subcutaneous, intramuscular, intravenous and intradermal). Syringes or multiple dose Vials made of glass or plastic. It will be appreciated that the preferred route will vary with 0109) A variety of pharmaceutical forms can be the condition and age of the recipient, the nature of the employed. Thus, if a Solid carrier is used, the preparation can condition to be treated, and the chosen active compound. be tableted, placed in a hard gelatin capsule in powder or 0105. It will be appreciated that the actual dosages of the pellet form or in the form of a troche or lozenge. The amount compounds used in the compositions of this invention will of solid carrier may vary, but generally will be from about vary according to the particular complex being used, the 25 mg to about 1g. If a liquid carrier is used, the preparation particular composition formulated, the mode of administra will be in the form of Syrup, emulsion, Soft gelatin capsule, tion, and the particular site, host, and disease being treated. Sterile injectable Solution or Suspension in an ampoule or Optimal dosages for a given Set of conditions may be Vial or non-aqueous liquid Suspension. US 2003/0055090 A1 Mar. 20, 2003

0110. To obtain a stable water-soluble dose form, a 0116 Pharmaceutical preparations which can be used pharmaceutically acceptable Salt of an inventive agent is orally include push-fit capsules made of gelatin, as well as dissolved in an aqueous Solution of an organic or inorganic Soft, Sealed capsules made of gelatin and a plasticizer, Such acid, Such as 0.3M Solution of Succinic acid or citric acid. If as glycerol or Sorbitol. The push-fit capsules can comprise a Soluble Salt form is not available, the agent may be the active ingredients in admixture with fillerS Such as dissolved in a Suitable co-Solvent or combinations of co lactose, binderS Such as Starches, and/or lubricants Such as Solvents. Examples of Suitable co-Solvents include, but are talc or magnesium Stearate, and, optionally, Stabilizers. In not limited to, alcohol, propylene glycol, polyethylene gly Soft capsules, the active agents may be dissolved or SuS col 300, polysorbate 80, glycerin and the like in concentra pended in Suitable liquids, Such as fatty oils, liquid paraffin, tions ranging from 0-60% of the total volume. In an exem or liquid polyethylene glycols. In addition, Stabilizers may plary embodiment, the antivesicant compound of the present be added. All formulations for oral administration should be invention is dissolved in DMSO and diluted with water. in dosages Suitable for Such administration. For buccal 0111. The composition may also be in the form of a administration, the compositions may take the form of Solution of a Salt form of the active ingredient in an tablets or lozenges formulated in conventional manner. appropriate aqueous vehicle Such as water or isotonic Saline 0117 Oral compositions generally include an inert dilu or dextrose Solution. ent or an edible carrier. They can be enclosed in gelatin 0112 The compositions of the invention may be manu capsules or compressed into tablets. For the purpose of oral factured in manners generally known for preparing pharma therapeutic administration, the active compound can be ceutical compositions, e.g., using conventional techniques incorporated with excipients and used in the form of tablets, Such as mixing, dissolving, granulating, dragee-making, troches, or capsules. Oral compositions can also be prepared levigating, emulsifying, encapsulating, entrapping or lyo using a fluid carrier for use as a mouthwash, wherein the philizing. Pharmaceutical compositions may be formulated compound in the fluid carrier is applied orally and Swished in a conventional manner using one or more physiologically and expectorated or Swallowed. Pharmaceutically compat acceptable carriers, which may be Selected from excipients ible binding agents, and/or adjuvant materials can be and auxiliaries that facilitate processing of the active com included as part of the composition. The tablets, pills, pounds into preparations which can be used pharmaceuti capsules, troches and the like can comprise any of the cally. following ingredients, or compounds of a similar nature: a 0113 Proper formulation is dependent upon the route of binder Such as microcrystalline cellulose, gum tragacanth or administration chosen. For injection, the agents of the inven gelatin; an excipient Such as Starch or lactose, a disintegrat tion may be formulated into aqueous Solutions, preferably in ing agent Such as alginic acid, Primogel, or corn Starch; a physiologically compatible bufferS Such as Hanks Solution, lubricant Such as magnesium Stearate or Sterotes, a glidant Ringer's Solution, or physiological Saline buffer. For trans Such as colloidal Silicon dioxide, a Sweetening agent Such as mucosal administration, penetrants appropriate to the barrier Sucrose or Saccharin; or a flavoring agent Such as pepper to be permeated are used in the formulation. Such penetrants mint, methyl Salicylate, or orange flavoring. Preferred for are generally known in the art. mulations for oral formulations include microcrystalline tablets, gelatin capsules, or the like. 0114. For oral administration, the compounds can be formulated readily by combining the active compounds with 0118 For administration intranasally or by inhalation, the pharmaceutically acceptable carriers known in the art. Such compounds for use according to the present invention are carriers enable the compounds of the invention to be for conveniently delivered in the form of an aeroSol Spray mulated as tablets, pills, dragees, capsules, liquids, gels, presentation from pressurized packs or a nebuliser, with the Syrups, Slurries, Suspensions and the like, for oral ingestion use of a Suitable propellant, e.g., dichlorodifluoromethane, by a patient to be treated. Pharmaceutical preparations for trichlorofluoromethane, dichlorotetrafluoroethane, carbon oral use can be obtained using a Solid excipient in admixture dioxide or other Suitable gas. In the case of a pressurized with the active ingredient (compound), optionally grinding aeroSol the dosage unit may be determined by providing a the resulting mixture, and processing the mixture of granules Valve to deliver a metered amount. Capsules and cartridges after adding Suitable auxiliaries, if desired, to obtain tablets of gelatin for use in an inhaler or insufflator and the like may or dragee cores. Suitable excipients include: fillerS Such as be formulated comprising a powder mix of the compound Sugars, including lactose, Sucrose, mannitol, or Sorbitol, and and a Suitable powder base Such as lactose or Starch. cellulose preparations, for example, maize Starch, wheat Starch, rice Starch, potato Starch, gelatin, gum, methyl cel 0119) The compounds may be formulated for parenteral lulose, hydroxypropylmethyl-cellulose, Sodium carboxym administration by injection, e.g., by bolus injection or con ethylcellulose, or polyvinylpyrrolidone (PVP). If desired, tinuous infusion. Formulations for injection may be pre disintegrating agents may be added, Such as crosslinked Sented in unit-dosage form, e.g., in ampoules or in multi polyvinyl pyrrollidone, agar, or alginic acid or a Salt thereof dose containers, with an added preservative. The Such as Sodium alginate. compositions may take Such forms as Suspensions, Solutions or emulsions in oily or aqueous vehicles, and may comprise 0115 Dragee cores are provided with suitable coatings. formulatory agents Such as Suspending, Stabilizing and/or For this purpose, concentrated Sugar Solutions may be used, dispersing agents. which may optionally comprise gum arabic, polyvinyl pyr rolidone, Carbopol gel, polyethylene glycol, and/or titanium 0120 Pharmaceutical compositions suitable for inject dioxide, lacquer Solutions, and Suitable organic Solvents or able use include Sterile aqueous Solutions (where water Solvent mixtures. Dyestuffs or pigments may be added to the Soluble) or dispersions and Sterile powders for the extem tablets or dragee coatings for identification or to characterize poraneous preparation of Sterile injectable Solutions or dis different combinations of active compounds and agents. persion. Aqueous injection Suspensions may comprise Sub US 2003/0055090 A1 Mar. 20, 2003

stances which increase the Viscosity of the Suspension, Such agents. Suitable Solvents include ethanol, acetone, glycols, as Sodium carboxymethyl cellulose, Sorbitol, or dextran. polyurethanes, and others known in the art. Suitable emol Optionally, the Suspension may also comprise Suitable Sta lients include petrolatum, mineral oil, propylene glycol bilizers or agents which increase the Solubility of the com dicaprylate, lower fatty acid esters, lower alkyl ethers of pounds to allow for the preparation of highly concentrated propylene glycol, cetyl alcohol, cetostearyl alcohol, Stearyl Solutions. Additionally, Suspensions of the active agents may alcohol, Stearic acid, wax, and others known in the art. be prepared as appropriate oily injection Suspensions. Suit Suitable humectants include glycerin, Sorbitol, and others able lipophilic Solvents or vehicles include fatty oils. Such as known in the art. Suitable emulsifiers include glyceryl Sesame oil, or Synthetic fatty acid esters, Such as ethyl oleate monoStearate, glyceryl monoleate, Stearic acid, polyoxyeth or triglycerides, or liposomes. ylene cetyl ether, polyoxyethylene cetoStearyl ether, poly oxyethylene Stearyl ether, polyethylene glycol Stearate, pro 0121 For intravenous administration, Suitable carriers pylene glycol Stearate, and others known in the art. Suitable include physiological Saline, bacteriostatic water, Cremo pH agents include hydrochloric acid, phosphoric acid, phor ELTM (BASF, Parsippany, N.J.) or phosphate buffered diethanolamine, triethanolamine, Sodium hydroxide, saline (PBS). In all cases, the composition must be sterile monobasic Sodium phosphate, dibasic Sodium phosphate, and should be fluid to the extent that easy syringability and others known in the art. Suitable preservatives include exists. It must be stable under the conditions of manufacture benzyl alcohol, Sodium benzoate, parabens, and others and Storage and must be preserved against the contaminating known in the art. action of microorganisms. Such as bacteria and fungi. The carrier can be a Solvent or dispersion medium comprising, 0.125 For administration to the eye, the compound of the for example, water, ethanol, polyol (for example, glycerol, invention is delivered in a pharmaceutically acceptable propylene glycol, and liquid polyetheylene glycol, and the ophthalmic vehicle Such that the compound is maintained in like), and Suitable mixtures thereof. The proper fluidity can contact with the ocular Surface for a Sufficient time period to be maintained, for example, by the use of a coating Such as allow the compound to penetrate the corneal and internal lecithin, by the maintenance of the required particle size in regions of the eye, including, for example, the anterior the case of dispersion and by the use of Surfactants. Pre chamber, posterior chamber, vitreous body, aqueous humor, vention of the action of microorganisms can be achieved by Vitreous humor, cornea, iris/cilary, lens, choroid/retina and various antibacterial and antifungal agents, for example, Selera. The pharmaceutically acceptable ophthalmic vehicle parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, may be an ointment, vegetable oil, or an encapsulating and the like. In many cases, it will be preferable to include material. A compound of the invention may also be injected isotonic agents, for example, Sugars, polyalcohols Such as directly into the vitreous and aqueous humor. manitol, Sorbitol, Sodium chloride in the composition. Pro longed absorption of the injectable compositions can be 0.126 Alternatively, the active ingredient may be in pow brought about by including in the composition an agent der form for constitution with a Suitable vehicle, e.g., Sterile which delays absorption, for example, aluminum pyrogen-free water, before use. The compounds may also be formulated in rectal compositions Such as Suppositories or monoStearate and gelatin. retention enemas, e.g., comprising conventional Suppository 0122) Sterile injectable solutions can be prepared by bases Such as cocoa butter or other glycerides. incorporating a therapeutically effective amount of a com pound of the invention in an appropriate Solvent with one or 0127. In addition to the formulations described above, the a combination of ingredients enumerated above, as required, compounds may also be formulated as a depot preparation. followed by filtered sterilization. Generally, dispersions are Such long-acting formulations may be administered by prepared by incorporating the antivesicant compound into a implantation (for example, Subcutaneously or intramuscu Sterile vehicle which comprises a basic dispersion medium larly) or by intramuscular injection. Thus, for example, the and the required other ingredients from those enumerated compounds may be formulated with Suitable polymeric or above. In the case of Sterile powders for the preparation of hydrophobic materials (for example, as an emulsion in an Sterile injectable Solutions, the preferred methods of prepa acceptable oil) or ion-exchange resins, or as sparingly ration are vacuum drying and freeze-drying which yields a Soluble derivatives, for example, as a sparingly Soluble Salt. powder of the active compound plus any additional desired 0128. A pharmaceutical carrier for hydrophobic com ingredient from a previously Sterile-filtered Solution thereof. pounds is a coSolvent System comprising benzyl alcohol, a 0123 Systemic administration can also be by transmu nonpolar Surfactant, a water-miscible organic polymer, and cosal or transdermal means. For transmucosal or transder an aqueous phase. The cosolvent system may be a VPD mal administration, penetrants appropriate to the barrier to co-solvent system. VPD is a solution of 3% w/v benzyl be permeated are used in the formulation. Such penetrants alcohol, 8% w/v of the nonpolar surfactant polysorbate 80, are generally known in the art, and include, for example, for and 65% w/v polyethylene glycol 300, made up to volume transmucosal administration, detergents, bile Salts, and in absolute ethanol. The VPD co-solvent system (VPD:5W) fusidic acid derivatives. Transmucosal administration can be comprises VPD diluted 1:1 with a 5% dextrose in water accomplished through the use of nasal SprayS or Supposito solution. This co-solvent system dissolves hydrophobic compounds well, and itself produces low toxicity upon ries. For transdermal administration, the active compounds Systemic administration. Naturally, the proportions of a are formulated into ointments, Salves, gels, foams, powders, co-Solvent System may be varied considerably without Sprays, aerosols or creams as generally known in the art. destroying its Solubility and toxicity characteristics. Further 0.124 For example, for topical formulations, pharmaceu more, the identity of the co-Solvent components may be tically acceptable excipients may comprise Solvents, emol varied, for example: other low-toxicity nonpolar Surfactants lients, humectants, preservatives, emulsifiers, and pH may be used instead of polysorbate 80; the fraction size of US 2003/0055090 A1 Mar. 20, 2003 polyethylene glycol may be varied; other biocompatible determining the LDs (the dose lethal to 50% of the popu polymers may replace polyethylene glycol, e.g. polyvinyl lation) and the EDs (the dose therapeutically effective in pyrrollidone; and other Sugars or polysaccharides may be 50% of the population). The dose ratio between toxic and Substituted for dextrose. therapeutic effects is the therapeutic indeX and it can be 0129. Alternatively, other delivery systems for hydropho expressed as the ratio LDs/EDs. Compounds which bic pharmaceutical compounds may be employed. Lipo exhibit large therapeutic indices are preferred. While com Somes and emulsions are known examples of delivery pounds that exhibit toxic side effects may be used, care vehicles or carriers for hydrophobic drugs. Certain organic should be taken to design a delivery System that targets Such Solvents Such as dimethylsulfoxide also may be employed, compounds to the Site of affected tissue in order to minimize although usually at the cost of greater toxicity. Additionally, potential damage to uninfected cells and, thereby, reduce the compounds may be delivered using a Sustained-release side effects. System, Such as Semipermeable matrices of Solid hydropho bic polymers comprising the therapeutic agent. Various 0.136 The data obtained from the cell culture assays and Sustained-release materials have been established and are animal Studies can be used in formulating a range of dosage known by those skilled in the art. Sustained-release capsules for use in humans. The dosage of Such compounds lies may, depending on their chemical nature, release the com preferably within a range of circulating concentrations that pounds for a few weeks up to over 100 dayS. Depending on include the EDso with little or no toxicity. The dosage may the chemical nature and the biological Stability of the vary within this range depending upon the dosage form therapeutic reagent, additional Strategies for protein Stabili employed and the route of administration utilized. For any Zation may be employed. compound used in the method of the invention, the thera 0130. The pharmaceutical compositions also may com peutically effective dose can be estimated initially from cell prise Suitable Solid- or gel-phase carriers or excipients. culture assayS. A dose may be formulated in animal models Examples of Such carriers or excipients include calcium to achieve a circulating plasma concentration range that carbonate, calcium phosphate, Sugars, Starches, cellulose includes the ICso (i.e., the concentration of the test com derivatives, gelatin, and polymerS Such as polyethylene pound which achieves a half-maximal inhibition of Symp glycols. toms) as determined in cell culture. Such information can be 0131 Some of the compounds of the invention may be used to more accurately determine useful doses in humans. provided as Salts with pharmaceutically compatible counter Levels in plasma may be measured, for example, by high ions. Pharmaceutically compatible salts may be formed with performance liquid chromatography. many acids, including hydrochloric, Sulfuric, acetic, lactic, tartaric, malic, Succinic, etc. Salts tend to be more Soluble in 0137 The following examples are intended to illustrate aqueous or other protonic Solvents than are the correspond but not to limit the invention. ing free-base forms. 0.132. In one embodiment, the active compounds are EXAMPLE 1. prepared with carriers that will protect the compound against rapid elimination from the body, Such as a controlled release Mouse Ear Antivesicant Drug Screening ASSay formulation, including implants and microencapsulated delivery Systems. Biodegradable, biocompatible polymers 0138. The effect of topical application of HD to the can be used, Such as ethylene Vinyl acetate, polyanhydrides, medial aspect of the right ear was evaluated in albino male polyglycolic acid, collagen, polyorthoesters, and polylactic mice (CD-1 Strain, Charles Rivers Laboratory, Kingston, acid. Methods for preparation of such formulations will be N.Y.) weighing about 25 to about 35 grams. Mice were apparent to those skilled in the art. The materials can also be weighed, marked for identification and anesthetized with a obtained commercially from Alza Corporation and Nova combination of ketamine (60 mg/kg) and xylazine (12 Pharmaceuticals, Inc. Liposomal Suspensions can also be mg/kg) given as an intraperitoneal injection. In a fume hood, used as pharmaceutically acceptable carriers. These can be 5ul (0.16 mg) of a 195 mM solution of neat (undiluted) HD prepared according to methods known to those skilled in the (d=1.27 g/ml; MW 159; purity 97.5%) in methylene chloride art, for example, as described in U.S. Pat. No. 4,522,811. was applied to the medial Surface of the right ear of each 0133. It is especially advantageous to formulate oral or mouse using a digital microliter positive displacement parenteral compositions in dosage unit form for ease of pipette. This volume of HD allowed even distribution of the administration and uniformity of dosage. Dosage unit form vesicant agent over the entire medial Surface of the ear. as used herein refers to physically discrete units Suited as 0.139 Mice were returned to polycarbonate cages for unitary dosages for the Subject to be treated; each unit recovery, observation and treatment. Each cage was covered comprising a predetermined quantity of active compound with a plastic backed paper diaper and warmed using a calculated to produce the desired therapeutic effect in asso circulating water heating pad placed under the container. All ciation with the required pharmaceutical carrier. animals were housed in the hood until euthanized in a 0134) The specification for the dosage unit forms of the halothane-filled chamber. The animals were euthanized 24 invention are dictated by and directly dependent on the hours after exposure. Immediately after euthanasia, full unique characteristics of the active compound and the par thickness circular 8 mm punched specimens were taken ticular therapeutic effect to be achieved, and the limitations from the center of each ear, placed into tarred 1.5 ml inherent in the art of compounding Such an active compound microfuge vials, and weighed to the nearest 0.1 mg on an for the treatment of individuals. analytical balance to determine tissue wet weight. This 0135 Toxicity and therapeutic efficacy of such com tissue wet-weight was used to determine an index of edema pounds can be determined by Standard pharmaceutical pro (relative ear weight, REW), which was used as the primary cedures in cell cultures or experimental animals, e.g., for quantitative response to tissue injury. US 2003/0055090 A1 Mar. 20, 2003 15

with hematoxylin/eosin (H&E) for microscopic evaluation. Histopathologic endpoints, Subepidermal blister and epider (exposed ear - control ear) REW = --- X 100 mal necrosis, as described below, were given Severity Scores. control ear See also Casillas, R. P., et al. (1997) Tox. Meth. 7:381-397 and Monteiro-Riviere, N. A., et al. (1999) J. Appl. Toxicol. 0140. Each 8 mm punched biopsy specimen was then 19, 313-328, both of which are herein incorporated by divided. One half of the tissue was placed into a vial reference. comprising 10% neutral buffered formalin (NBF) for histo 0143 (a). Subepidermal blister (SEB; epidermal-dermal pathological evaluation while the remaining half was Snap Separation) and opposite side (contralateral) Subepidermal frozen in liquid nitrogen for immunohistochemistry or for blister (CSEB; unexposed outer surface). A SEB is any later processing in biochemical or molecular biology assayS. defect or discontinuity involving detachment of basal cells 0141 For each experiment, 10 mice per treatment group from the basement membrane. were used. The right ears of all groups of mice were exposed to HD liquid. Treatment groups were administered candidate 0144 (b). Epidermal necrosis (EN; exposed inner ear antivesicant drugs as a pre-treatment (15 minutes before HD Surface) and opposite side (contralateral) epidermal necrosis exposure) or post-treatment. Each mouse acted as its own (CEN; unexposed outer ear Surface). Epidermal necrosis control since the left ear was only treated with HD vehicle denotes cellular death in the epithelium. (MeCl). In addition, 10 mice per experiment were used as HD positive controls. Previous in-house Studies using a 0145 The severity scores were as follows: 0=no lesion or one-way analysis of variance (ANOVA) revealed no signifi change; 1 =change in less than 5% of the entire tissue cant histopathologic differences in the effects of a methylene section; 2=change is present in 10%-40% of the entire tissue chloride (HD vehicle) treated ear and a control ear. There section; 3=change is present in 50%-80% of the entire tissue fore, methylene chloride was only used on control ears that Section, 4=change is present in greater than 90% of the entire were used for biochemical or molecular biology assayS. tissue Section. Scores were reported as the mean of each grOup. 0142. After fixation in neutral buffered formalin (NBF), tissues were embedded in paraffin then Sectioned and Stained 0146 The results are shown in Table 1 as follows:

TABLE 1.

Time of Application Compound (before or after % REW 76 SEB % EN % CEN Name Total Dose exposure reduction reduction reduction reduction

MPNO 0.6 mg -15 minute 35.96 SO.OO 5.88 65.63 0.6 mg +10 minute 59.71 1OO 54.55 66.67 0.6 mg +10 minute 36.12 88.89 30.77 77.14 0.6 mg +20 minute 6.37 77.78 7.69 48.57 0.15 mg -15 minute 27.24 75.OO 10.53 44.12 0.3 mg -15 minute 38.2O 75.OO 31.58 55.88 0.6 mg -15 minute 41.65 SO.OO 26.32 SO.OO 1.2 mg -15 minute 47.68 75.OO 31.58 91.18 2.4 mg -15 minute 6942 1OO 6842 94.12 0.15 mg +10 minute 7.02 25.OO 2.78 46.67 0.3 mg +10 minute 3.29 1OOOO -8.33 53.33 0.6 mg +10 minute 1.27 SO.OO 8.33 46.67 1.2 mg +10 minute 26.24 SO.OO 2.78 SO.OO 2.4 mg +10 minute 24.71 O.OO -5.56 53.33 4-Me-MPNO 0.6 mg -15 minute 57.05 25.OO 14.71 93.75 0.6 mg +10 minute 7.29 44.44 5.56 65.81 0.6 mg +10 minute 67.78 1OOOO 57.58 85.19 0.6 mg +20 minute O.64 SO.OO 2.50 28.21 0.15 mg -15 minute 25.37 O.OO 10.81 71.88 0.3 mg -15 minute 38.95 6O.OO 13.51 68.75 0.6 mg -15 minute 57.20 1OOOO 29.73 71.88 1.2 mg -15 minute 48.70 6O.OO 27.03 75.OO 2.4 mg -15 minute 6911 8O.OO 48.65 84.38 0.15 mg +10 minute 34.01 57.14 2.56 6O.OO 0.3 mg +10 minute 41.93 57.14 10.26 68.57 0.6 mg +10 minute 40.36 71.43 7.69 65.71 1.2 mg +10 minute 30.99 71.43 7.69 71.43 2.4 mg +10 minute 30.40 85.71 20.51 68.57 6-Me-MPNO 0.6 mg -15 minute 42.15 SO.OO 17.65 56.25 0.6 mg +10 minute 27.61 SO.OO 24.24 59.26 0.6 mg +10 minute 35.74 61.43 3.33 24.40 0.6 mg +20 minute 25.19 87.14 3.33 31.60 0.6 mg +60 minute 22.17 74.29 3.33 17.20 0.15 mg -15 minute 1981 -25.00 7.89 41.18 0.3 mg -15 minute 21.62 -25.00 5.26 52.94 0.6 mg -15 minute 14.63 -50.00 O.OO 35.29 US 2003/0055090 A1 Mar. 20, 2003 16

TABLE 1-continued

Time of Application Compound (before or after % REW % SEB % EN % CEN Name Total Dose exposure reduction reduction reduction reduction 1.2 mg -15 minute 47.8O SO.OO O.OO 67.65 2.4 mg -15 minute 40.13 75.00 23.68 64.71 0.15 mg +10 minute 0.97 O.OO -8.57 17.86 0.3 mg +10 minute 10.95 O.OO -5.71 32.14 0.6 mg +10 minute 19.47 SO.OO 5.71 35.71 1.2 mg +10 minute 19.98 O.OO 2.86 17.86 2.4 mg +10 minute 10.39 25.OO -5.71 57.14 4,6-di-Me- 0.6 mg -15 minute 36.85 in?t in?t in?t MPNO 5-Br-MPNO 0.6 mg -15 minute 15.61 in?t in?t 5-C-MPNO 0.6 mg -15 minute 5.32 in?t in?t 3-C-MPNO 0.6 mg -15 minute 18.31 in?t in?t MPNO = 2-mercaptopyridine-N-oxide; Me = Methyl: % REW = % Reduction in mouse EarWeight; SEB 7% reduction = % reduction in severity of Sub-epidermal Blister; EN 76 reduction = % reduction in severity of Epidermal Necrosis; CEN 76 reduction = % reduction in severity of Contralateral Epidermal Necrosis, as compared with the untreated control mouse year. 0147 To the extent necessary to understand or complete 4,6-dimethyl-2-mercaptopyridine-N-oxide, the disclosure of the present invention, all publications, 5-bromo-2-mercaptopyridine-N-oxide; patents, and patent applications mentioned herein are expressly incorporated by reference therein to the same 5-methyl-2-mercaptopyridine-N-oxide; extent as though each were individually So incorporated. 3-chloro-2-mercaptopyridine-N-oxide; 0148 Having thus described exemplary embodiments of 5-chloro-2-mercaptopyridine-N-oxide; the present invention, it should be noted by those skilled in 4-chloro-2-mercaptopyridine-N-oxide; the art that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifica 3,4,5-methoxy-2-mercaptopyridine-N-oxide, tions may be made within the Scope of the present invention. 6-methoxy-2-mercaptopyridine-N-oxide; Accordingly, the present invention is not limited to the 5-trifluoromethyl-2-mercaptopyridine-N-oxide; Specific embodiments as illustrated herein, but is only lim ited by the following claims. 2-mercaptoquinoline-N-oxide, or a pharmaceutically acceptable Salt or prodrug thereof. We claim: 5. The compound of claim 1, wherein the compound is an 1. A compound having the Structural formula antivesicant. 6. A pharmaceutical composition comprising a compound R2 R1 having the Structural formula R-( Y-sh R2 R1 N+ V R-( Y-sh R4 O N+ V wherein R', R, R, and R" are each independently H, or R4 O a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy wherein R', R, R, and R" are each independently H, or a loxy group, or a pharmaceutically acceptable Salt or methyl, halo, trifluoromethyl, nitro, alkyloxy, or acyloxy prodrug thereof. group, or a pharmaceutically acceptable Salt or prodrug 2. The compound of claim 1, wherein two adjacent R thereof, and a pharmaceutically acceptable excipient. Substituents form a cycloalkyl, heterocycloalkyl, aryl, or 7. The pharmaceutical composition of claim 6, wherein heteroaryl group. two adjacent R Substituents form a cycloalkyl, heterocy 3. The compound of claim 1, wherein R', R, R, and R' cloalkyl, aryl, or heteroaryl group. are each independently H, methyl, methoxy, chloro, fluoro, 8. The pharmaceutical composition of claim 6, wherein or bromo. R", R, R, and R" are each independently H, methyl, 4. The compound of claim 1, wherein the compound is methoxy, chloro, fluoro, or bromo. 2-mercaptopyridine-N-oxide; 9. The pharmaceutical composition of claim 6, wherein the compound is 4-methyl-2-mercaptopyridine-N-oxide; 2-mercaptopyridine-N-oxide; 6-methyl-2-mercaptopyridine-N-oxide; 4-methyl-2-mercaptopyridine-N-oxide; US 2003/0055090 A1 Mar. 20, 2003 17

6-methyl-2-mercaptopyridine-N-oxide; wherein R', R, R, and R" are each independently H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy 4,6-dimethyl-2-mercaptopyridine-N-oxide, loxy group, or a pharmaceutically acceptable Salt or 5-bromo-2-mercaptopyridine-N-oxide; prodrug thereof to a Subject. 19. The method of claim 18, wherein the compound is 5-methyl-2-mercaptopyridine-N-oxide; administered before exposure to the vesicant agent. 3-chloro-2-mercaptopyridine-N-oxide; 20. The method of claim 18, wherein the compound is 5-chloro-2-mercaptopyridine-N-oxide; administered during exposure to the vesicant agent. 21. The method of claim 18, wherein the compound is 4-chloro-2-mercaptopyridine-N-oxide; administered after exposure to the vesicant agent. 3,4,5-methoxy-2-mercaptopyridine-N-oxide; 22. The method of claim 18, wherein the injury is an HD-induced injury. 6-methoxy-2-mercaptopyridine-N-oxide; 23. The method of claim 18, wherein the compound is 5-trifluoromethyl-2-mercaptopyridine-N-oxide; administered topically. 24. The method of claim 18, wherein the compound is 2-mercaptoquinoline-N-oxide, administered Systemically. or a pharmaceutically acceptable Salt or prodrug thereof. 25. A method of decontaminating an area exposed to a 10. The pharmaceutical composition of claim 6, further Vesicant agent comprising contacting a compound having comprising a Second antivesicant compound. the structural formula 11. The pharmaceutical composition of claim 6, further comprising a Supplementary active compound. R2 R1 12. A protectant or a decontaminant comprising a com pound having the Structural formula R-/ Y-sh N+ R2 R1 V R4 O R-/ Y-sh wherein R', R, R, and R' are each independently H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy R4 Y. loxy group with the area. 26. A kit for treating, preventing, or inhibiting an injury wherein R', R, R, and R" are each independently H, or induced by a vesicant agent comprising at least one com a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy pound having the Structural formula loxy group. R2 R1 13. The protectant or a decontaminant of claim 12, wherein the protectant or decontaminant is clothing, combat gear, a protective shelter, a Weapon, a piece of equipment, a R-( Y-sh filter, a Sponge, a foam, a Spray, a lotion, or a gas. N+ 14. The protectant or a decontaminant of claim 12, V wherein the protectant or a decontaminant may be used to R4 O prevent exposure of a Subject to a vesicant agent. 15. The protectant or a decontaminant of claim 12, wherein R', R, R, and R" are each independently H, or wherein the protectant or a decontaminant may be used to a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy treat a Subject exposed to a vesicant agent or an injury loxy group, or a pharmaceutically acceptable Salt or induced by a vesicant agent. prodrug thereof and instructions for use. 16. The protectant or a decontaminant of claim 12, 27. A kit for decontaminating an area exposed to a wherein the protectant or a decontaminant may be used to vesicant agent comprising at least one compound having the decontaminate a Subject or object exposed to a vesicant Structural formula agent. 17. The protectant or a decontaminant of claim 12, further R2 R1 comprising a Second antivesicant compound, a Supplemen tary active compound, or both. R-( Y-sh 18. A method of treating, preventing, or inhibiting an N+ injury induced by a vesicant agent comprising administering V at least one compound having the Structural formula R4 O R2 R1 wherein R', R, R, and R" are each independently H, or a methyl, halo, trifluoromethyl, nitro, alkyloxy, or acy R3 / \ SH loxy group and instructions for use. 28. A kit comprising a protectant or decontaminant and N+ V instructions for use. R4 O