HK1121163B

HK1121163B - Derivatives of 4-or 5-aminosalicylic acid

Info

Publication number: HK1121163B
Application number: HK08112729.5A
Authority: HK
Inventors: G．西里诺; G．卡里安多; V．桑塔加达; S．费奥卢西; J．L．沃雷斯; A．斯帕拉托尔
Original assignee: 安泰碧控股公司
Priority date: 2005-05-27
Filing date: 2006-03-31
Publication date: 2012-12-28

Description

Derivatives of 4-or 5-aminosalicylic acid

Technical Field

The present invention relates to compounds useful in the treatment of intestinal diseases such as Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS) and colon cancer chemoprevention. In particular, 4-and 5-aminosalicylic acid derivatives have been developed having a hydrogen sulfide releasing moiety attached to the 5-or 4-aminosalicylic acid molecule via an azo, ester, anhydride, thioester or amide bond.

Background

Inflammatory Bowel Disease (IBD) is a general term for diseases that cause inflammation of the small intestine and colon. Ulcerative colitis is the most common inflammatory bowel disease, affecting many parts of the Gastrointestinal (GI) tract, particularly the lower GI tract, more particularly the colon and/or rectum. The second IBD is Crohn's disease, which occurs mainly in the small intestine (ileum) and large intestine (colon).

Ulcerative colitis is difficult to diagnose and its symptoms resemble other bowel diseases and crohn's disease. Crohn's disease differs from ulcerative colitis in that it causes deeper inflammation into the intestinal wall. Meanwhile, crohn's disease usually occurs in the small intestine, although it also occurs in the mouth, esophagus, stomach, duodenum, large intestine, cecum and anus.

Ulcerative colitis may occur in people of any age, but most commonly it begins at age 15 to 30, or less commonly between the ages of 50 to 70. Children and adolescents also sometimes develop this disease. Ulcerative colitis affects both men and women equally, and in some families infections can occur.

It is also important to consider that about 5% of patients with ulcerative colitis develop colon cancer. The risk of cancer increases with the duration and extent of colon involvement. For example, if only the lower colon and rectum are involved, the risk of cancer is not higher than normal. However, if the entire colon is involved, the risk of cancer is 32 times higher than normal. Therefore, it is highly likely that the drug for treating IBD can also be used for the prevention of colon cancer.

The pathogenesis of IBD may involve multifactorial interactions between genetic factors, immune factors and environmental triggers. Recent evidence suggests that pathological activation of the mucosal immune system in response to an antigen is a key factor in the pathogenesis of IBD.

The presence of antigens in inflammatory processes is followed by the production of cytokines, small glycoprotein peptide molecules that generate communication signals in different cell populations to determine the direction of subsequent immune and inflammatory responses. Proinflammatory cytokines include Interleukins (IL) -1, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha). Macrophages are the major source of cytokines, and epithelial cells also produce many of these types of peptide factors.

T helper (Th) cells are a more important source of cytokines. Th1 cells associated with cell-mediated immune responses produce IL-2, interferon gamma (IFN-. gamma.) and TNF-. alpha.. In connection with the regulation of inflammation, NFkB, and in particular key transcription factors involved in the pathogenesis of IBD regulate the amount of cytokines produced by Th1 cells (see Neurath et al (1996) Nature Med.2: 998-1004). Th2 cells enhance antibody synthesis by B cells and produce IL-4, IL-5, IL-6 and IL-10.

Chemokines are also considered to be causative agents of colitis. Chemokines are pro-inflammatory proteins that participate in immune and inflammatory responses through chemical ligation and activation of granulocytes. For example, RANTES is a C-C chemokine that promotes the recruitment and activation of inflammatory cells such as monocytes, lymphocytes, mast cells, and eosinophils. Recently, it has also been demonstrated that RANTES increases during the chronic phase of colitis (see Ajuebor et al (2001) J. Immunol.166: 552-.

Treatment of ulcerative colitis depends on the severity of the disease. Most human medications, and in severe cases, patients require surgical resection of the diseased colon.

Irritable Bowel Syndrome (IBS), a common but poorly understood condition, causes a number of intestinal symptoms including abdominal pain, diarrhea and/or constipation, bloating, flatulence and cramps. Although these symptoms can be the result of many different bowel diseases, IBS is often diagnosed after the elimination of more serious problems. There is increasing evidence for a role for inflammation in the pathogenesis of IBS.

The goal of treatment is to induce and maintain remission, and improve the quality of life of IBD/IBS patients. Several drugs can be used.

Drugs comprising 5-aminosalicylic acid (5-ASA, mesalamine) or 4-aminosalicylic acid (4-ASA) -aminosalicylates are useful for controlling inflammation. However, mesalamine and 4-ASA are absorbed when passing through the GI tract, adversely affecting the amount of mesalamine that reaches the lower GI tract, particularly the colon and rectum. Therefore, a number of mesalamine preparations have been introduced in an attempt to protect mesalamine while passing through the intestine (gut) and upper GI tract.

In addition, several prodrugs of mesalamine have been introduced, which can deliver mesalamine specifically in the colon. These prodrugs are less absorbable in the intestine and upper GI tract and therefore more readily reach the colon.

Sulfasalazine is a combination of sulfapyridine and 5-ASA used to induce and maintain remission. Sulfasalazine is metabolized in the body to 5-ASA and sulfapyridine. The sulfapyridine component carries the anti-inflammatory agent 5-ASA into the intestine.

However, sulfapyridine can cause side effects such as nausea, vomiting, heartburn, diarrhea, and headache. These side effects are usually caused by the activity of sulfapyridine in the GI tract and its absorption into the system.

Other 5-ASA agents such as olsalazine, ipratropium and balsalazide have different carriers, respectively, have few side effects, and can be used in people who cannot take sulfapyridine. Unlike sulfapyridine, the breakdown of these 5-ASA compounds in the intestinal tract does not produce undesirable metabolites.

Typically, 5-ASA compounds are administered orally in enemas, or in suppositories, depending on the location of the inflammation in the colon. Most people with mild or moderate ulcerative colitis are first treated with this type of drug. However, this therapy is not generally considered optimal, mainly due to the poor efficacy of the drug, which also leads to poor patient compliance.

Other drugs that may be used are corticosteroids such as prednisone, hydrocortisone, budesonide, and the like and immunomodulators such as azathioprine and 6-mercaptopurine (6-MP). These drugs can cause side effects such as hypertension, increased risk of infection, and the like.

Sulfasalazine, olsalazine and balsalazide are derivatives of mesalamine in which a non-mesalamine carrier is linked to mesalamine through a diazo bond. These prodrugs are not readily absorbed in the intestine and upper GI tract and therefore may reach the colon where they are cleaved by the azo-reductases of the colonic microbiota, releasing mesalazine and carriers directly into the colon.

Other derivatives of mesalazine include carriers linked to mesalazine through the carboxyl and hydroxyl functions of the molecule. Among them, the preparation of esters or amides from amino acids such as L-tryptophan and L-glycine or the addition of other biological compounds such as taurine has been reported. These prodrugs are based on their activity on the action of carboxypeptidase and aminopeptidase A to release mesalamine. (R.Pellicciari et al (1993) Journal of Medicinal Chemistry, 36, pg.4201-7).

Most of the carrier moieties associated with mesalazine in the prior art are inert. Thus, it is desirable to link a carrier moiety to either 5-ASA or 4-ASA, which are also biologically active and can be used to treat IBD/IBS.

Brief description of the invention

In general, H can be released in tissue₂Hydrogen sulfide (H) of S₂S) the release moiety is linked to the 4-or 5-aminosalicylic acid (4-or 5-ASA) molecule via an azo, ester, anhydride, thioester or amide bond to form the 4-or 5-ASA derivatives of the present invention. By H₂Covalent attachment of the S-releasing moiety to 4-or 5-ASA, the derivatives of the invention may act as prodrugs which are less absorbable in the intestinal and upper GI tract and therefore more accessible to the colon.

The anti-inflammatory properties of 4-or 5-ASA and their use in the treatment of ulcerative colitis are widely reported in the literature. 4-or 5-ASA reduced intestinal inflammation, diarrhea (frequent stools), rectal bleeding and stomach pain. Recently, H₂S has been shown to function as a neuromodulator, exhibiting anti-inflammatory effects. Furthermore, H₂S has been shown to modulate nociception to colorectal distension (see Distrutti et al (2005) event fat moisture exogenous Effects in the Gastrointestinal Tract activity K_ATPChannels.j.pharm.and exp.ther.316: 325 — 335, incorporated herein by reference). Finally, H₂S has been shown to exhibit Smooth Muscle relaxation In Intestinal tissue (see, Teague, B. et al (2002), The smoothened Muscle Relaxant effect Hydrogen Sulfide In Vitro: evolution for a Physiological Roleto Control In tissue, Br.Pharmacol.137.139-145, herein incorporated by reference).

Surprisingly, with H alone₂S Release fraction compared with H₂Covalent attachment of the S-releasing moiety to 4-or 5-ASA modified H₂H of the S moiety₂S release capacity. This indicates that when H is present₂Covalent binding of the S releasing moiety to 4-or 5-ASA, and H₂The S-releasing moiety is cleaved with 4-or 5-ASA by hydrolysis or cleavage by various enzymes present in the GI tract to release the two active ingredients (i.e., further acting 4-or 5-aminosalicylic acid and H₂S-releasing moiety), H can be released₂S。

The derivatives of the invention are superior to 4-or 5-ASA, H alone in reducing inflammation, in reducing diarrhea and fecal occult blood in colitis patients, and in reducing visceral pain associated with colorectal distension₂S-releasing moiety and 4-or 5-ASA with H₂S-releasing part of the mixture. In addition, the derivatives of the present invention also reduce the mRNA levels of Cyclooxygenase (COX)1, COX-2, constitutive endothelial nitric oxide synthase (eNOS), and Inducible NOS (iNOS), enzymes believed to be involved in inflammation.

Thus, in one aspect of the invention, the derivatives of the invention may be used to treat inflammation of the Gastrointestinal (GI) tract, such as Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS). Without being bound by any theory, it is believed that the hydrogen sulfide released from the hydrogen sulfide releasing moiety exhibits anti-inflammatory effects, including inhibition of NFkB, transcription factors that regulate the expression of several pre-inflammatory genes. Further, it is considered that H₂The antinociceptive effects of S may be related to ATP-sensitive K⁺(K_ATP) The channels are related.

In another aspect of the present invention, the 4-or 5-ASA derivative of the present invention can effectively reduce the viability of HT-29 human colon cancer cells and thus can be used for the prevention and/or treatment of colon cancer.

Broadly, the compounds of the invention have the following general formula:

A-L-R (I)

wherein:

a is

wherein-N is in position 4 or 5,

wherein-NH is in the 4 or 5 position,

wherein-NH₂In the 4 or 5-bit state,

or

wherein-NH₂At position 4 or 5;

l is O, O-C ═ O, S, N or a covalent bond to form an ester, anhydride, thioester, amide or azo bond; and

r is the release of H in tissue₂The hydrogen sulfide releasing portion of S. It is to be understood that any release of H in tissue can be used in the present invention₂The non-toxic, effective hydrogen sulfide releasing portion of S.

In a preferred embodiment, R is selected from:

or

In biological tissues, all of the above moieties release H₂S; however, most of H₂The S-releasing moiety functions by a different mechanism than N-acetylcysteine. It is well known that N-acetylcysteine is converted to cysteine in various tissues, and that the in vivo metabolism of cysteine produces H₂S。H₂S is mainly produced by two types of pyridoxal 5' -phosphate-dependent enzymes responsible for L-cysteine metabolism, namely cystathionine gamma-lyase and cystathionine beta-synthase (see Fujii et al (2005) Hydrogen sulfite as an endogenous modulator of binary Bicarbonate evolution in the Rat liver, Antioxidid.Redox Signal.7: 788-Incorporated herein by reference).

Pharmaceutically acceptable salts, such as salts with alkali and alkaline earth metals, non-toxic amines and amino acids, are also part of the invention. Preferred salts are those with arginine and agmatine. Pharmaceutically acceptable acid addition salts are also included.

In a further aspect of the invention, there is provided a pharmaceutical composition of a compound of the invention and a pharmaceutically acceptable excipient or carrier, particularly for use in the treatment of inflammation of the GI tract.

According to other embodiments of the invention, a method of treating inflammation of the GI tract, such as Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS), in a patient in need thereof, comprises administering to the patient an effective amount of a 4-or 5-ASA derivative or a salt thereof. Further, there is provided a method of treating or preventing colon cancer in a subject in need thereof comprising administering to the subject an effective amount of a 4-or 5-ASA derivative and salts thereof.

In a further embodiment, the present invention provides the use of 4-or 5-ASA derivatives and their salts in the manufacture of a medicament for the treatment of inflammation of the GI tract. The invention also provides the use of 4-or 5-ASA derivatives and their salts for the treatment of inflammation of the GI tract.

Preferred compounds are those of the following formulae:

2-hydroxy-4-or 5- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenylazo ] -benzoic acid (II),

4-or 5-amino-2-hydroxy-benzoic acid 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl ester (III),

4 or 5-amino-2- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonyloxy ] -benzoic acid (IV),

2-hydroxy-4 or 5[4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonylamino ] -benzoic acid (V),

4-or 5- { [ (1-carboxy-2-mercapto-ethylcarbamoyl) -methyl ] -azo } -2-hydroxy-benzoic acid (VI),

4-or 5-amino-2-hydroxy-benzoic acid (1-carboxy-2-mercapto-ethylcarbamoyl) -methyl ester (VII),

4-or 5-amino-2- [ (1-carboxy-2-mercapto-ethylcarbamoyl) -methoxycarbonyloxy ] -benzoic acid (VIII),

4-or 5- [ (1-carboxy-2-mercapto-ethylcarbamoyl) -methoxycarbonylamino ] -2-hydroxy-benzoic acid (IX),

4-or 5-amino-2-hydroxy-benzoic anhydride (X) with N-acetylcysteine,

4-or 5- (2-acetylamino-3-mercapto-propionylamino) -2-hydroxy-benzoic acid (XI),

2- (2-acetylamino-3-mercapto-propionyloxy) -4-or 5-amino-benzoic acid (XII),

2-hydroxy-4 or 5- ({4- [4- (4-methoxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetans (dithiadiphosphetans) -2-yl radicals]-phenoxymethyl } -azo) -benzoic acid (XIII),

4-or 5-amino-2- {4- [4- (4-methoxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxymethoxycarbonyloxy } -benzoic acid (XIV),

2-hydroxy-4-or 5- {4- [4- (4-methoxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxymethoxycarbonylamino } -benzoic acid (XV),

4-or 5-amino-2-hydroxy-benzoic acid 4- [4- (4-methoxy-phenyl) -2, 4-dithio-2 lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxymethyl ester (XVI),

4-or 5-amino-2-hydroxy-benzoic acid 4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2 lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenyl ester (XVII),

4-or 5-amino-2- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]

Dithiadiphosphetan-2-yl ] -phenoxy carbonyl oxy } -benzoic acid (XVIII),

2-hydroxy-4-or 5- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]

Dithiadiphosphetan-2-yl ] -phenoxycarbonylamino } -benzoic acid (XIX),

4-or 5- (1-carboxy-3-thiocarbamoyl-propylazo) -2-hydroxy-benzoic acid (XX),

2- (4-or 5-amino-2-hydroxy-benzoylamino) -4-thiocarbamoyl-butyric acid (XXI),

4-or 5-amino-2- (1-carboxy-3-thiocarbamoyl-propylcarbamoyloxy) -benzoic acid (XXII),

2-hydroxy-4-or 5- [3- (1-hydroxymethyl-3-thiocarbamoyl-propyl) -ureido ] -benzoic acid (XXIII),

4-or 5-amino-2- (2-amino-4-thiocarbamoyl-butyryloxy) -benzoic acid (XXIV),

4-or 5- (2-amino-4-thiocarbamoyl-butyrylamino) -2-hydroxy-benzoic acid (XXV),

4-or 5-amino-2-hydroxy-benzoic anhydride with 2-amino-4-thiocarbamoyl-butyric acid (XXVI),

4-Thiocarbamoylphenyl 4-or 5-amino-2-hydroxybenzoates (XXVII),

4-or 5-amino-2- (4-thiocarbamoyl-phenoxycarbonyloxy) -benzoic acid (XXVIII),

2-hydroxy-4-or 5- (4-thiocarbamoyl-phenoxycarbonylamino) -benzoic acid (XXIX),

thiocarbamoyl methyl 4-or 5-amino-2-hydroxy-benzoate (XXX),

4-or 5-amino-2-thiocarbamoylmethoxycarbonyloxy-benzoic acid (XXXI),

2-hydroxy-4-or 5-thiocarbamoylmethoxycarbonylamino-benzoic acid (XXXII),

4-or 5-amino-2-hydroxy-benzoic anhydride (XXXIII) with sulfuric acid mono- (2-mercapto-ethyl) ester,

4-or 5-amino-2- (2-mercapto-ethoxysulfonyloxy) -benzoic acid (XXXIV), and

5-amino-2-hydroxy-benzoic acid 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl ester (XXXV).

The most preferred compounds are the following:

5-amino-2-hydroxy-benzoic acid 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl ester (XXXV);

4-thiocarbamoylphenyl 4-or 5-amino-2-hydroxybenzoate (XXVII); and

4-or 5-amino-2-hydroxy-benzoic anhydride (X) with N-acetylcysteine.

Brief Description of Drawings

Figure 1 shows the disease efficacy score of mice with TNBS-induced colitis after treatment with increasing doses of mesalazine and compound XXXV of the invention.

FIG. 2 shows Myeloperoxidase (MPO) activity in mice with TNBS-induced colitis after treatment with increasing doses of mesalazine and compound XXXV of the present invention.

FIG. 3 shows the disease efficacy scores in mice with TNBS-induced colitis after treatment with compound XXXV, mesalamine alone, 5-p-hydroxyphenyl-1, 2-dithiole (dithiole) -3-thione (ADT-OH) alone, and a mixture of mesalamine and ADT-OH.

FIG. 4 shows Myeloperoxidase (MPO) activity in mice with TNBS-induced colitis after treatment with compound XXXV, mesalamine alone, ADT-OH alone, and a mixture of mesalamine and ADT-OH.

Figure 5 shows the disease efficacy scores in mice with TNBS-induced colitis after treatment with compound XXVII, mesalamine alone, 4-hydroxythiobenzamide (4-HTB) alone, and a mixture of mesalamine and 4-HTB.

FIG. 6 shows Myeloperoxidase (MPO) activity in mice with TNBS-induced colitis after treatment with compound XXVII, mesalamine alone, 4-hydroxythiobenzamide (4-HTB) alone, and a mixture of mesalamine and 4-HTB.

FIG. 7 shows Myeloperoxidase (MPO) activity in mice with TNBS-induced colitis after treatment with 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

Figure 8 shows the disease efficacy score in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIG. 9 shows colon tumor necrosis factor (TNF-. alpha.) mRNA expression in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIG. 10 shows interferon gamma (IFN-. gamma.) mRNA expression in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIG. 11 shows the expression of various Interleukin (IL) mRNAs, namely IL-1, -2, 10 and-12 mRNAs, in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalamine and an equivalent dose of compound XXXV of the present invention.

FIG. 12 shows colonic levels of RANTES mRNA in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIG. 13 shows colon COX-1 and COX-2 mRNA expression in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIG. 14 shows colon eNOS and iNOS mRNA expression in mice with TNBS-induced colitis after treatment with vehicle (1% CMC), 50mg/kg mesalazine and an equivalent dose of compound XXXV of the present invention.

FIGS. 15(a) and (b) show sensory scores in rat models of visceral pain perception using mesalazine and Compound XXXV of the present invention, respectively.

FIGS. 16(a) and (b) show the intra-rectal pressure in a rat model of visceral pain perception using mesalazine and Compound XXXV of the present invention, respectively.

FIG. 17 shows the pain scores for mesalamine, compound XXXV and compound XXVII with and without glibenclamide.

FIG. 18 shows the pain perception scores for compound XXXV, compound XXVII, mesalamine, ADT-OH and 4-HBT.

FIG. 19 shows leukocyte adhesion in response to intragastric administration of aspirin.

FIG. 20 is a bar graph of leukocyte adhesion at the end of the assay (60-65 minutes).

FIG. 21 is a bar graph showing cysteine, ADT-OH, Compound XXXV, 4-HTB and H for Compound XXVII₂S is generated.

FIG. 22 is a concentration-response curve showing H according to the present invention₂Vasodilation of the S-released fraction.

Detailed description of the preferred embodiments

The invention will now be described with reference to the preferred embodiments described herein. It should be understood that these embodiments are for purposes of illustration and are not intended to limit the scope of the invention, which is defined by the claims.

The compounds of the present invention comprise two active moieties, 4-or 5-ASA and a hydrogen sulfide releasing moiety, linked together by an azo, ester, anhydride, thioester or amide bond. The presence of azoreductase allows the release of 4-or 5-ASA from the azo linkage prodrug, thus targeted delivery into the colon, while reducing systemic absorption. Similarly, the presence of carboxypeptidase and aminopeptidase A also allows the release of 4-or 5-ASA from the ester and amide prodrugs, respectively. Esterases and thioesterases will cleave ester and thioester bonds, respectively. Finally, the lipase will cleave the anhydride linkage. The compounds of the invention can be prepared using known starting materials and reagents.

The compounds of the present invention may be used for the prevention or treatment of various diseases, in particular inflammation of the GI tract, including, but not limited to, oral inflammation such as mucositis, infectious diseases (e.g., viral, bacterial and fungal diseases) and crohn's disease, inflammation of the esophagus such as esophagitis, diseases caused by chemical injury (e.g., ingestion of lye), gastroesophageal reflux disease, bile acid reflux, barrett's esophagus, crohn's disease and esophageal stenosis, inflammation such as gastritis (e.g., helicobacter pylori, acid-peptic disease and atrophic gastritis), celiac disease, peptic ulcer disease, precancerous lesions of the stomach, non-ulcerative dyspepsia and crohn's disease, inflammation of the stomach such as crohn's disease, bacterial overgrowth, peptic ulcer disease, and intestinal fissure, inflammation of the colon such as crohn's disease, ulcerative colitis, irritable bowel syndrome, infectious colitis (e.g., pseudomembranous colitis such as carboxydothial colitis, salmonellosis, shigella infection, yersinia, cryptosporidiosis, microsporidian infection and viral infection), radiation-induced colitis, colitis in an immunocompromised host (e.g. cecronitis), precancerous lesions of the colon (e.g. dysplasia, inflammation of the bowel and colon polyps), proctitis, inflammation associated with hemorrhoids, spastic anal pain, rectal fissures; liver, gallbladder and/or biliary diseases such as cholangitis, sclerosing cholangitis, primary biliary cirrhosis, and cholecystitis; and anal abscess.

The compounds of the present invention may be administered to a patient in any suitable therapeutically effective and safe amount, depending on the particular condition or disease state to be treated, as can be readily determined by one skilled in the art. Most desirably, these compounds are administered in a dosage range of about 1 to about 2000mg per day, in single or multiple doses, although variations may be necessary depending on the weight and condition of the patient to be treated and the particular route of administration chosen. Most desirably, however, the dosage level will range from about 0.1 to about 100mg/kg, preferably from about 5 to 90mg/kg, and most preferably from about 5 to 50 mg/kg. But may vary depending on the weight, condition and individual response to the drug of the patient to be treated, as well as the type of pharmaceutical formulation selected and the time and interval at which administration is carried out. In some cases dosage levels below the lower limit of the aforesaid range may be more than adequate, while in other cases still larger doses may be employed without causing any harmful side effects, provided that the larger dose is first divided into several smaller doses for administration throughout the day.

The compounds of the invention may be administered in any pharmaceutical formulation, the nature of which depends on the route of administration. These pharmaceutical compositions may be prepared by conventional methods using compatible, pharmaceutically acceptable excipients or carriers. Examples of such compositions include capsules, tablets, transdermal patches, lozenges, troches, sprays, syrups, powders, granules, gels, elixirs, suppositories, and the like, for the preparation of extemporaneous solutions, injectable preparations, rectal, ocular, vaginal preparations, and the like. Preferred routes of administration are oral and rectal.

When used for oral administration, tablets may be employed which contain various excipients such as microcrystalline cellulose, sodium citrate, calcium carbonate, dicalcium phosphate and glycine as well as various disintegrants such as starch (preferably corn, potato or tapioca starch), alginic acid and certain complex silicates, together with particulate binders such as polyvinylpyrrolidone, sucrose, gelatin and acacia. In addition, lubricants such as magnesium stearate, sodium lauryl sulfate and talc may be used for tableting. Solid compositions of a similar type may also employ fillers in the capsule, preferred materials relating thereto also include lactose or milk sugar and high molecular weight polyethylene glycols. When aqueous suspensions and/or elixirs are desired for oral use, the active ingredient may be combined with sweetening or flavoring agents, coloring matter and emulsifying and/or suspending agents, as desired, together with diluents such as water, ethanol, propylene glycol, glycerin and various like combinations thereof.

The dosage form may be designed for immediate release, controlled release, extended release, delayed release, or targeted delayed release. The definitions of these terms are known to those skilled in the art. In addition, the release profile of the dosage form may be affected by the composition of the polymeric mixture, the composition of the coating matrix, the composition of the multiparticulates, the composition of the coating multiparticulates, the composition based on ion exchange resins, the composition based on osmotic action or the composition of the biodegradable polymer. Without wishing to be bound by theory, it is believed that release may be affected by favorable diffusion, dissolution, erosion, ion exchange, osmosis, or a combination thereof.

When administered parenterally, sesame or peanut oil or aqueous propylene glycol solutions of the active compounds may be administered. If necessary, the aqueous solution should be suitably buffered (preferably to a pH greater than 8), the liquid diluent being isotonic first. Aqueous solutions are suitable for intravenous injection purposes. The preparation of all of these solutions under sterile conditions is readily accomplished by standard pharmaceutical techniques well known to those of ordinary skill in the art.

The following non-limiting examples are further described to enable one of ordinary skill in the art to make and use the invention.

Preparation of the Compounds

Example 1

Synthesis of 2-hydroxy-5- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenylazo ] -benzoic acid (4) [ Compound of formula II ]

Synthesis of (4-propenyl-phenyl) -carbamic acid tert-butyl ester (2)

To 25ml of 4-propenyl-phenylamine (1) (10.0mmol) was added under stirring at 0 ℃ over a half hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave (4-propenyl-phenyl) -carbamic acid tert-butyl ester (2) (90% yield).

Synthesis of 5- (4-amino-phenyl) - [1, 2] dithiole-3-thione (3)

(4-propenyl-phenyl) -carbamic acid tert-butyl ester (2, 4.5mmol) and sulphur (31.5mmol) were heated in dimethylformamide (500ml) for 8 h; the residue was almost completely dissolved in toluene after removal of the solvent. An attempt was made to extract the toluene solution with a 2N aqueous solution of sodium hydroxide to obtain a precipitate as an orange solid. This product was dissolved in boiling water, treated with 4N hydrochloric acid at room temperature for 30 minutes, and 4N NaOH was added to give the desired product (3) (yield 55%).

Synthesis of 2-hydroxy-5- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenylazo ] -benzoic acid (4)

5- (4-amino-phenyl) - [1, 2] dithiole-3-thione (3, 0.56mmol) was dissolved in a mixture of 5ml of concentrated HCl and 2.5ml of water and diazotized with a solution of sodium nitrite (0.56 mmol). Meanwhile, salicylic acid (0.56mmol), potassium hydroxide (1.12mmol) and sodium carbonate were dissolved in water. The diazo suspension is added portionwise to an alkaline solution of salicylic acid, the alkalinity being maintained at a sufficiently high level throughout the reaction by adding a further amount of potassium hydroxide solution. After 2 days, the reaction mixture was heated at 50 ℃ for 30 minutes, the precipitated diazo compound (4) was filtered off by HCl (yield 85%) to give the compound of formula II, 2-hydroxy-5- [4- (5-thio-5H- [1, 2] dithiol 3-yl) -phenylazo ] -benzoic acid.

Example 2

Synthesis of 2-hydroxy-4- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenylazo ] -benzoic acid (2) [ Compound of formula II ]

Synthesis of 2-hydroxy-4- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenylazo ] -benzoic acid (2)

4-amino-2-hydroxy-benzoic acid (1, 1mmol) was dissolved in a mixture of 10mL concentrated HCl and 5mL water and diazotized with sodium nitrite (1mmol) solution. The diazo suspension is added portionwise to a solution of 5-phenyl- [1, 2] dithiole-3-thione (1mmol) in dimethylformamide. After 2 days, the reaction mixture was heated at 50 ℃ for 30 minutes. After cooling, the precipitated diazo compound (2) was filtered off (yield 65%) via HCl to give the compound of formula II, 2-hydroxy-5- [4- (5-thio-5H- [1, 2] dithiolen-3-yl) -phenylazo ] -benzoic acid.

Example 3

General procedure for the Synthesis of 4- (5-thio-5H- [1, 2] dithiolen-3-yl) -phenyl 4-or 5-amino-2-hydroxy-benzoate (4) [ Compound of formula XXXV ]

Synthesis of 5-p-hydroxyphenyl-1, 2-dithiole-3-thione (ADT-OH)

Anethole (1) (32.5g, 0.21mol) and sulfur (45g, 1.40mol) were heated in dimethylformamide (250ml) for 8 hours; the residue was almost completely dissolved in toluene after removal of the solvent. An attempt was made to extract the toluene solution with 2N aqueous sodium hydroxide solution to give a precipitate (8.5g) as an orange solid with m.p. above 300 ℃. This product was dissolved in boiling water to give an orange precipitate (2) (50% yield), m.p.188-189 ℃ after addition of hydrochloric acid.¹H NMR(DMSO)δ6.86(d，2H)，7.68(s，1H)，7.75(d，2H)，10.51(s，-OH)；MS(ESI)，m/z 225(M^-)。

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

25mL of two of 4-or 5-aminosalicylic acid (10.0mmol) are added under stirring at 0 ℃ over a half hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (80% yield).

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Compound (1) (12.0mmol), concentrated H at room temperature₂SO₄(6.0mmol) and DCM (100mL) were stirred under isobutylene gas (5psi) for 6 h. With cold 10% NaHCO₃The solution was washed (2X 100mL) and brine (100mL) and dried (Na)₂SO₄) And evaporated. The residue was dissolved in 1: 1 MeOH/CCl₄(400mL), washed with water (300mL) and then extracted with 1: 1 MeOH/water (2X 200 mL). Drying (Na)₂SO₄) The extracts were evaporated to give white solid (2) which was recrystallized from DCM/hexane (83% yield).

Synthesis of 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl 4-or 5-amino-2-hydroxy-benzoate (4)

To a solution of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 ℃ over 1 hour. 5-p-hydroxyphenyl-1, 2-dithiole-3-thione (ADT-OH) (3.0mmol) was added to the reaction mixture, and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; washed with brineOrganic layer over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (3) is solution processed. After 2 hours, the solvent was removed to give compound 3 as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, whereby 4- (5-thio-5H- [1, 2-thio) -4-or 5-amino-2-hydroxybenzoic acid is obtained]Dithiolan-3-yl-phenyl ester (4) [ compounds of formula XXXV](40% yield).

The compound 5-amino-2-hydroxy-benzoic acid 4- (5-thio-5H- [1, 2)]Dithiolen-3-yl) -phenyl ester (4):¹H NMR(DMSO)δ7.07(d，2H)，7.38(d，2H)，7.46(d，2H)，7.79(s，1H)，7.85(s，1H)，8.01(d，2H)，10.35(s，-OH)；MS(ESI)，m/z 362(M⁺)。

example 4

2- (tert-Butoxycarbonyl) -4-or 5-aminophenylbicarbonate (5)

General procedure for the Synthesis of 3- (tert-Butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (6)

Synthesis of 4-or 5-amino-2-ethoxycarbonyloxy-benzoic acid (1) and 4-or 5-ethoxycarbonylamino-2-hydroxy-benzoic acid (2)

4-or 5-aminosalicylic acid (3.0mmol) was dissolved in 40mL of chloroform in a round-bottom flask equipped with a drying tube. Ethyl chloroformate (3.0mmol) was gradually added and the solution was refluxed for 2 hours. The chloroform was evaporated in vacuo and the residue was taken up in ether. The ether phase was decolorized with charcoal, filtered and the solvent removed in vacuo. The resulting residue was then dissolved in ethanol and precipitated with n-hexane to recover the crude oily semi-solid product. The crude product was purified by flash chromatography on silica gel eluting with ether/hexane (73, v/v) to give the title compounds 4-or 5-amino-2-ethoxycarbonyloxy-benzoic acid (1: yield 58%) and 4-or 5-ethoxycarbonylamino-2-hydroxybenzoic acid (2: yield 34%).

Synthesis of 4-or 5-amino-2-ethoxycarbonyloxy-benzoic acid tert-butyl ester (3)

To a solution of (1) (3.0mmol) in 50ml of dimethylformamide was added, with stirring and at 0 ℃ in the course of 1 hour, hydroxy-phenylpropyl-triazole (3.3mmol) and DCC (3.3 mmol). To the reaction mixture was added tert-butanol (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9.5/0.5) elution, which gave 4-or 5-amino-2-ethoxycarbonyloxy-benzoic acid tert-butyl ester (3) (55% yield).

Synthesis of 4-or 5-ethoxycarbonylamino-2-hydroxy-benzoic acid tert-butyl ester (4)

Compound (4) was obtained according to the reported method for obtaining Compound (3). Yield: 74 percent

Synthesis of 2- (tert-butoxycarbonyl) -4-or 5-aminophenylbicarbonate (5)

To a solution of compound (3) (3.5 g; 0.011mol) in ethanol (80ml) was added NaOH1N (40 ml). The reaction mixture was stirred at room temperature for 2 hours. The solution was then neutralized with HCl 1N. Ethanol was removed and extracted with ethyl acetate (3X 150 ml); the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate solvent: to obtain 2- (tert-butoxycarbonyl) -4-or 5-aminophenylbicarbonate (5) (3 g; 0.010 mol; yield: 89%) as a white solid.

Synthesis of 3- (tert-butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (6)

Compound (6) was obtained according to the reported method for obtaining Compound (5). Yield: 91 percent

Example 5

General procedure for the Synthesis of 4-or 5-amino-2- (1-carboxy-3-thiocarbamoyl-propylcarbamoyloxy) -benzoic acid (11) [ Compound of formula XXII ], 4-or 5- [3- (1-carboxy-3-thiocarbamoyl-propyl) -ureido ] -2-hydroxy-benzoic acid (12)

Synthesis of 5-thio-L-glutamine-OtBu (2)

L-Glutamine-OtBu HCl (1) (1.2 mmol; 0.3g) and Lawesson's reagent (0.75 mmol; 0.3g) were added to benzene (20mL) and the mixture was heated at reflux for 15 min. The reaction was then cooled and evaporated in vacuo. The crude product is chromatographed on 100g of silica gel, eluting with a mixture of ethyl acetate and n-hexane. 0.2g (76% yield) of product (2) was obtained as a white solid:¹H NMR(CDCl₃)δ1.4(s，9H)，1.8-2.8(m，5H)，4.0-4.8(m，3H)；MS(ESI)，m/z 219(M⁺)。

synthesis of 2- (tert-Butoxycarbonyl) -4-or 5-tert-butyloxycarbonyl aminophenylbicarbonate (7)

25ml of two (5) (10.0mmol) are stirred at 0 ℃ in half an hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. In the evaporation ofAfter the solvent was added, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 2- (tert-butoxycarbonyl) -4-or 5-tert-butoxycarbonylaminophenylbicarbonate (7) (80% yield).

Synthesis of 3- (tert-butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (8)

Compound 6(12.0mmol), concentrated H at room temperature₂SO₄(6.0mmol) and DCM (100mL) were stirred under isobutylene gas (5psi) for 6 h. With cold 10% NaHCO₃The solution was washed (2X 100mL) and brine (100mL) and dried (Na)₂SO₄) And evaporated. The residue was dissolved in 1: 1 MeOH/CCl₄(400mL), washed with water (300mL) and then extracted with 1: 1 MeOH/water (2X 200 mL). Drying (Na)₂SO₄) The extracts were evaporated to give a white solid (8) which was recrystallized from DCM/hexane (83% yield).

Synthesis of 4-or 5-amino-2- (1-carboxy-3-thiocarbamoyl-propylcarbamoyloxy) -benzoic acid (11)

To a solution of (7) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) over 1 hour with stirring at 0 deg.C. To the reaction mixture was added 2-amino-4-thiocarbamoyl-butyric acid tert-butyl ester (3.0mmol) and triethylamine (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (9) is worked up in solution. After 2 hours, the solvent was removed to obtain compound (11) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, whereby 4-or 5-amino-2- (1-carboxy-3-thiocarbamoyl-propylcarbamoyloxy) -benzoic acid (11) [ compound of formula XXII](45% yield).

Synthesis of 4-or 5- [3- (1-carboxy-3-thiocarbamoyl-propyl) -ureido ] -2-hydroxy-benzoic acid (12)

Compound (12) was obtained according to the reported method for obtaining Compound (11). Yield: 38 percent of

Example 6

4-or 5-amino-2- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonyloxy ] -benzoic acid (15) [ Compound of formula IV ]

General Synthesis of 2-hydroxy-4-or 5- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonylamino ] -benzoic acid (16) [ Compound of formula V ]

Synthesis of 5-p-hydroxyphenyl-1, 2-dithiole-3-thione (ADT-OH)

Anethole (1) (32.5g, 0.21mol) and sulfur (45g, 1.40mol) were heated in dimethylformamide (250ml) for 8 hours; the residue was almost completely dissolved in toluene after removal of the solvent. An attempt was made to extract the toluene solution with 2N aqueous sodium hydroxide solution to give a precipitate (8.5g) as an orange solid with m.p. above 300 ℃. This product was dissolved in boiling water to give an orange precipitate (2) after addition of hydrochloric acid, (yield 50%), m.p.188-189 ℃.¹H NMR(DMSO)δ 6.86(d，2H)，7.68(s，1H)，7.75(d，2H)，10.51(s，-OH)；MS(ESI)，m/z 225(M^-)。

25ml of two (5) (10.0mmol) are stirred at 0 ℃ in half an hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 2- (tert-butoxycarbonyl) -4-or 5-tert-butoxycarbonylaminophenylbicarbonate (7) (80% yield).

Synthesis of 3- (tert-butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (8)

Synthesis of 4-or 5-amino-2- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonyloxy ] -benzoic acid (15)

To a solution of (7) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) over 1 hour with stirring at 0 deg.C. 5-p-hydroxyphenyl-1, 2-dithiole-3-thione (ADT-OH) (3.0mmol) was added to the reaction mixture, and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (13) is solution processed. After 2 hours, the solvent was removed to obtain compound (15) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, whereby the compound 4-or 5-amino-2- [4- (5-thio-5H- [1, 2) of the formula IV is obtained]Dithiolan-3-yl) phenoxycarbonyloxy]-benzoic acid (15), (45% yield).

Synthesis of 2-hydroxy-4-or 5- [4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenoxycarbonylamino ] -benzoic acid (16)

Compound (16), a compound of formula V, was obtained according to the reported procedure for obtaining compound (15). Yield: 38 percent of

Example 7

4-or 5-amino-2- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxycarbonyloxy-

Benzoic acid (19) [ Compound XIV of formula ]

2-hydroxy-4-or 5- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxycarbonylamino } -

Benzoic acid (20) [ Compound of formula XIII ]

Synthesis of (p-hydroxyphenyl) -dithiophosphoric anhydride

Red P (4 g; 0.129mol), S (4 g; 0.125mol) and PhOH (4 g; 0.042mol) were heated at 155 ℃ and 158 ℃ for 5.5 hours, the reaction mixture was cooled at room temperature, and the precipitate was collected (5.5g, 34% yield). m.p.224-226 ℃. NMR and MS analyses were consistent with p-hydroxyphenyl dithiophosphoric anhydride.

Synthesis of 3- (tert-butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (8)

4-or 5-amino-2- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxy carbonyl oxygen } -benzoic acid(19) Synthesis of (2)

To a solution of (7) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) over 1 hour with stirring at 0 deg.C. To the reaction mixture was added p-hydroxyphenyldithiophosphoric anhydride (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (17) is solution processed. After 2 hours, the solvent was removed to obtain compound (19) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂/MeOH (8/2), whereby the compound of the formula XIV, 4-or 5-amino-2- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda. is obtained⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]-phenoxycarbonyloxy } -benzoic acid (19) (65% yield).

2-hydroxy-4-or 5- {4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]Synthesis of (20) -phenoxycarbonylamino } -benzoic acid

Compound (20), a compound of formula XIII, was obtained according to the reported procedure for obtaining compound (19). Yield: 48 percent

Example 8

4-or 5-amino-2- (4-thiocarbamoyl-phenoxycarbonyloxy) -benzoic acid (23) [ Compound of formula XXVIII ]

General Synthesis of 2-hydroxy-4-or 5- (4-thiocarbamoyl-phenoxycarbonylamino) -benzoic acid (24) [ Compound of formula XXIX ]

Synthesis of 3- (tert-butoxycarbonyl) -4-or 5-hydroxyphenyl-carbamic acid (8)

Compound (6) (12.0mmol), concentrated H at room temperature₂SO₄(6.0mmol) and DCM (100mL) were stirred under isobutylene gas (5psi) for 6 h. With cold 10% NaHCO₃The solution was washed (2X 100mL) and brine (100mL) and dried (Na)₂SO₄) And evaporated. The residue was dissolved in 1: 1 MeOH/CCl₄(400mL), washed with water (300mL) and then extracted with 1: 1 MeOH/water (2X 200 mL). Drying (Na)₂SO₄) The extracts were evaporated to give a white solid (8) which was recrystallized from DCM/hexane (83% yield).

Synthesis of 4-or 5-amino-2- (4-thiocarbamoyl-phenoxycarbonyloxy) -benzoic acid (23)

To a solution of (7) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) over 1 hour with stirring at 0 deg.C. 4-hydroxy-thiobenzamide (3.0mmol) was added to the reaction mixture, and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to removeAnd (4) removing the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (21) is solution processed. After 2 hours, the solvent was removed to obtain compound (23) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution thereby afforded compound 4-or 5-amino-2- (4-thiocarbamoyl-phenoxycarbonyloxy) -benzoic acid (23) of formula XXVII (71% yield).

Synthesis of 2-hydroxy-4-or 5- (4-thiocarbamoyl-phenoxycarbonylamino) -benzoic acid (24)

Compound (24), a compound of formula XXIX, is obtained according to the reported procedure for obtaining compound (23). Yield: 68 percent of

Example 9

2- (4-or 5-amino-2-hydroxy-benzoylamino) -4-thiocarbamoyl-butyric acid

(6) General Synthesis procedure for Compound of formula XXI

Synthesis of 5-thio-L-glutamine-OtBu (2)

L-Glutamine-OtBu HCl (1) (1.2 mmol; 0.3g) and Lawesson's reagent (0.75 mmol; 0.3g) were added to benzene (20mL) and the mixture was heated at reflux for 15 min. The reaction was then cooled and evaporated in vacuo. The crude product is chromatographed on 100g of silica gel, eluting with a mixture of ethyl acetate and n-hexane. 0.2g (76% yield) of product (2) is obtained as a white solid:¹H NMR(CDCl₃)δ1.4(s，9H)，1.8-2.8(m5H)，4.0-4.8(m，3H)；MS(ESI)，m/z 219(M⁺)。

synthesis of 4-or 5-tert-Butoxycarbonylamino-2-hydroxy-benzoic acid (1) to 25ml of 4-or 5-aminosalicylic acid (10.0mmol) at 0 ℃ under stirring in a half hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (80% yield).

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Synthesis of 2- (4-or 5-amino-2-hydroxy-benzoylamino) -4-thiocarbamoyl-butyric acid (6)

To a solution of 4-or 5-tert-butoxycarbonylamino-2-tert-butoxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 ℃ over 1 hour. Adding 2-amino-4-thioamine to the reaction mixtureT-butyl carbamoyl-butyrate (3.0mmol) and triethylamine (3.0mmol) were mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate (5) is worked up in solution. After 2 hours, the solvent was removed to obtain compound (6) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, which gave compound 2- (4-or 5-amino-2-hydroxy-benzoylamino) -4-thiocarbamoyl-butyric acid (6) of formula XXI (80% yield). MS (ESI), M/z 298 (M)⁺)。

Example 10

General procedure for the Synthesis of 4-or 5-amino-2-hydroxy-benzoic acid 4-thiocarbamoyl-phenyl ester (8) [ Compound of formula XXVII ]

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

25ml of 4-or 5-aminosalicylic acid (10.0mmol) are added to two under stirring at 0 ℃ in half an hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (80% yield).

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Synthesis of 4-or 5-amino-2-hydroxy-benzoic acid 4-thiocarbamoyl-phenyl ester (8)

To a solution of 4-or 5-tert-butoxycarbonylamino-2-tert-butoxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 ℃ over 1 hour. 4-hydroxy-thiobenzamide (3.0mmol) was added to the reaction mixture, and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with 40% TFA₂Cl₂The crude intermediate (7) is worked up in solution. After 2 hours, the solvent was removed to obtain compound (8) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution gave compound 4-or 5-amino-2-hydroxy-benzoic acid 4-thiocarbamoyl-phenyl ester (8) of formula XXVII (48% yield).

Example 11

4-or 5-amino-2-hydroxy-benzoic acid 4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2 lambda⁵，4λ⁵-[1，3，2，4]Dithio compoundsDiphosphetan-2-yl]Phenyl ester (10) [ Compound of formula XVII]General synthetic procedure of

Synthesis of (p-hydroxyphenyl) dithiophosphoric anhydride

Heating red P (4 g; 0.129mol), S (4 g; 0.125mol) and PhOH (4 g; 0.042mol) at 155-; the reaction mixture was cooled at room temperature and the precipitate was collected (5.5g, 34% yield). m.p.224-226 ℃. NMR and MS analyses were consistent with p-hydroxyphenyl dithiophosphoric anhydride.

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Compound (1) (12.0mmol), concentrated H at room temperature₂SO₄(6.0mmol) and DCM (100mL) were stirred under isobutylene gas (5psi) for 6 h. By using ice10％NaHCO₃The solution was washed (2X 100mL) and brine (100mL) and dried (Na)₂SO₄) And evaporated. The residue was dissolved in 1: 1 MeOH/CCl₄(400mL), washed with water (300mL) and then extracted with 1: 1 MeOH/water (2X 200 mL). Drying (Na)₂SO₄) The extracts were evaporated to give white solid (2) which was recrystallized from DCM/hexane (83% yield).

4-or 5-amino-2-hydroxy-benzoic acid 4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2 lambda⁵，4λ⁵-[1，3，2，4]Dithiodiphosphetan-2-yl radicals]Synthesis of phenyl ester (10)

To a solution of 4-or 5-tert-butoxycarbonylamino-2-tert-butoxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 ℃ over 1 hour. To the reaction mixture was added p-hydroxyphenyldithiophosphoric anhydride (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate 9 was solution processed. After 2 hours, the solvent was removed to give compound 10 as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂/MeOH (8/2), whereby the compound 4-or 5-amino-2-hydroxy-benzoic acid 4- [4- (4-hydroxy-phenyl) -2, 4-dithio-2. lambda. of the formula XVII is obtained⁵，4λ⁵ -[1，3，2，4]Dithiodiphosphetan-2-yl radicals]Phenyl ester (10), (73% yield).

Synthesis of 4-or 5-amino-2-hydroxy-benzoic acid mercaptoethanesulfonate (2)

A mixture of 2-mercapto-ethyl sulfite (0.1mol) in 100m l ethyl acetate was added to a solution of 4-or 5-aminosalicylic acid (1) (0.1mol in 100ml of ethyl acetate) under an inert atmosphere at 20-25 ℃ over 30-45 minutes. The mixture was then stirred at 0-5 ℃ for 1 hour and filtered to give 4-or 5-amino-2-hydroxy-benzoic acid mercaptoethanesulfonate (2) (yield 98%).

Example 12

Synthesis of 4 or 5-amino-2- (2-acetylamino-3-mercapto-propionyloxy) -benzoic acid (3) [ Compound of formula XII ]

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

Synthesis of 4 or 5-amino-2- (2-acetylamino-3-mercapto-propionyloxy) -benzoic acid (3)

To a solution of 2-acetylamino-3-mercapto-propionic acid (3.0mmol) in 50mL dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 deg.C over 1 hour. Adding 4-or 5-tert-butoxycarbonylamino-2-hydroxy to the reaction mixtureBenzoic acid (2) (3.0mmol), stirred mechanically at 0 ℃ for 3 hours, at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate (2) is solution processed. After 2 hours, the solvent was removed to obtain compound (3) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, whereby compound 4 or 5-amino-2- (2-acetylamino-3-mercapto-propionyloxy) -benzoic acid (3) of formula XII was obtained (52% yield).

Example 13

4-or 5-amino-2-hydroxy-benzoic anhydride with 2-acetamido-3-mercapto-propionic acid

(4) Synthesis of [ Compound of formula X ]

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-hydroxy-benzoic acid (1)

25ml of 5-aminosalicylic acid (10.0mmol) are added to two portions in half an hour with stirring at 0 deg.CTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (80% yield).

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Synthesis of 4 or 5-amino-2-hydroxy-benzoic anhydride (4) with 2-acetamido-3-mercapto-propionic acid

DCC (3.3mmol) was added to a solution of 4-or 5-tert-butoxycarbonylamino-2-tert-butoxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide over 1 hour with stirring at 0 ℃. To the reaction mixture was added 2-acetamido-3-mercapto-propionic acid (3.0mmol), which was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate (3) is solution processed. After 2 hours, the solvent was removed to give compound 4 as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, giving the compound of formula X, 4 or 5-amino-2-hydroxy-benzoic anhydride (4) with 2-acetamido-3-mercapto-propionic acid (68% yield).

Example 14

Synthesis of 4 or 5- (2-acetylamino-3-mercapto-propionylamino) -2-hydroxy-benzoic acid (5) [ Compound of formula XI ]

Synthesis of 4 or 5- (9H-fluoren-9-ylmethoxycarbonylamino) -2-hydroxy-benzoic acid (1)

25ml of 4-or 5-aminosalicylic acid (10.0mmol) are added to two under stirring at 0 ℃ in half an hourAlkane and 12.5ml of aqueous solution were added with Na₂CO₃10% (15mL) and Fmoc-OSu (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (90% yield).

Synthesis of 4 or 5-amino-2-tert-butoxy-benzoic acid tert-butyl ester (3)

Compound (1) (12.0mmol), concentrated H at room temperature₂SO₄(6.0mmol) and DCM (100mL) were stirred under isobutylene gas (7psi) for 24 h. With cold 10% NaHCO₃The solution was washed (2X 100mL) and brine (100mL) and dried (Na)₂SO₄) And evaporated. The residue was dissolved in 1: 1 MeOH/CCl₄(400mL), washed with water (300mL) and then extracted with 1: 1 MeOH/water (2X 200 mL). Drying (Na)₂SO₄) The extracts were evaporated to give a white solid (2). The crude intermediate (2) was treated with diethylamine (33%) in THF. After 2 hours, the solvent was removed to obtain compound (3) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution gave 4 or 5-amino-2-tert-butoxy-benzoic acid tert-butyl ester (3), (67% yield).

Synthesis of 4 or 5- (2-acetylamino-3-mercapto-propionylamino) -2-hydroxy-benzoic acid (5)

To a solution of 2-acetylamino-3-mercapto-propionic acid (3.0mmol) in 50mL dimethylformamide was added hydroxyphenyltriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 deg.C over 1 hour. To the reaction mixture was added 4 or 5-amino-2-tert-butoxy-benzoic acid tert-butyl ester (3) (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate 4 is solution processed. After 2 hours, the solvent was removed to obtain compound (5) as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution, whereby the compound of formula XI, 4 or 5- (2-acetylamino-3-mercapto-propionylamino) -2-hydroxy-benzoic acid (5), was obtained (78% yield).

Example 15

Synthesis of 4-or 5-amino-2- (2-mercapto-ethoxysulfonyloxy) -benzoic acid (3) [ compound of formula XXXIV ]

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

25ml of 4-or 5-aminosalicylic acid (10.0mmol) are added to two under stirring at 0 ℃ in half an hourTo the alkane and 12.5ml of the aqueous solution were added triethylamine (15.0mmol) and di-tert-butyl-dicarbonate (15.0 mmol). The reaction mixture was mechanically stirred at room temperature for 24 hours. After evaporation of the solvent, 3M HCl (15mL) was added dropwise to the residue. The precipitate was filtered, washed with water and dried. Will be provided withThe residue was loaded onto a silica gel column and washed with CH₂Cl₂MeOH (9/1) elution gave 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1) (80% yield).

Synthesis of 4 or 5-amino-2- (2-mercapto-ethoxysulfonyloxy) -benzoic acid (3)

To a solution of mono- (2-mercapto-ethyl) sulfate (3.0mmol) in 50mL of dimethylformamide was added hydroxybenzotriazole (3.3mmol) and DCC (3.3mmol) with stirring at 0 deg.C over 1 hour. 4-or 5-tert-Butoxycarbonylamino-2-hydroxy-benzoic acid (2) (3.0mmol) was added to the reaction mixture, and mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate (2) is solution processed. After 2 hours, the solvent was removed to give compound 3 as a crude residue. Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution gave the compound of formula XXXIV, 4 or 5-amino-2- (2-mercapto-ethoxysulfonyloxy) -benzoic acid (3), (57% yield).

Example 16

4-or 5-amino-2-hydroxy-benzoic anhydride with sulfuric acid mono- (2-mercapto-ethyl) ester

(4) Synthesis of [ Compound of formula XXXIII ]

Synthesis of 4-or 5-tert-butoxycarbonylamino-2-hydroxy-benzoic acid (1)

Synthesis of 4-or 5-tert-Butoxycarbonylamino-2-tert-butoxy-benzoic acid (2)

Synthesis of 4 or 5-amino-2-hydroxy-benzoic anhydride (4) with sulfuric acid mono- (2-mercapto-ethyl) ester

DCC (3.3mmol) was added to a solution of 4-or 5-tert-butoxycarbonylamino-2-tert-butoxy-benzoic acid (2) (3.0mmol) in 50mL of dimethylformamide over 1 hour with stirring at 0 ℃. To the reaction mixture was added sulfuric acid mono- (2-mercapto-ethyl) ester (3.0mmol), and the mixture was mechanically stirred at 0 ℃ for 3 hours and at room temperature for 72 hours. After filtration, the filtrate was evaporated under reduced pressure to remove the solvent. The oily residue thus obtained was dissolved in ethyl acetate; the organic layer was washed with brine, over anhydrous MgSO₄Dry, filter and evaporate the solvent. CH with TFA (40%)₂Cl₂The crude intermediate (3) is solution processed. After 2 hours, the solvent was removed to obtain a crude residue (4)). Loading the residue on a silica gel column and applying CH₂Cl₂MeOH (8/2) elution gave compound XXXIII, 4 or 5-amino-2-hydroxy-benzoic anhydride (4) formed with mono- (2-mercapto-ethyl) sulfate (68% yield).

Characterization of the Compounds

Example 17

5-amino-2-hydroxy-benzoic acid 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl ester [ referred to herein as Compound XXXV ]

In a Macherey-Nagel with a fluorescent indicator^TMThin layer chromatography was performed on a silica gel 50 plate, and the plate was developed with UV light (254 nm). Mixing Kieselgel^TM60 for column chromatography. All reagents were purchased from Aldrich-Sigma Chemical Company and used as received without purification. The solvent is of analytical reagent grade or higher purity, and the provided solvent is used. Adding Na to the solution₂SO₄Drying, using Buchi^TMR-114 rotavapor to remove the solvent in vacuo. By protons¹H-NMR and¹³C-NMR spectroscopy was used to confirm the structure by spectroscopy. Spectra were recorded on a Varian Mercury Plus400 instrument. Spectra were recorded in DMSO. The following abbreviations are used to describe the peak shapes, when appropriate: s (singlet), d (doublet). Chemical shift is by Me₄Si as an internal standard. In applied biosystems^TMMass spectrometry analysis of the synthesized product was performed on an API 2000 mass spectrometer. With Kofler^TMThe melting point was determined by a hot stage and was not calibrated.

¹H NMR(DMSO)δ7.07(d，2H)，7.38(d，2H)，7.46(d，2H)，7.79(s，1H)，7.85(s，1H)，8.01(d，2H)，10.35(s，-OH)；

¹³C NMR(DMSO)δ114.6，119.6；123.9；127.7；128.7；129.4；129.8；136.1；153.8；158.8，165.4；173.2；189.7，216.2MS(EI)，m/e 362(M⁺)；

m.p：93-95℃。

Example 18

5-amino-2-hydroxy-benzoic acid 4-thiocarbamoyl-phenyl ester [ referred to herein as Compound XXVII ]

Thin layer chromatography was performed on a Macherey-Nagel silica gel 50 plate with fluorescent indicator, and the plate was developed with UV light (254 nm). Kieselgel 60 was used for column chromatography. All reagents were purchased from Aldrich-Sigma Chemical Company and used as received without purification. The solvent is of analytical reagent grade or higher purity, and the provided solvent is used. Adding Na to the solution₂SO₄Dried and the solvent removed in vacuo using a Buchi R-114 rotary evaporator. By protons¹H-NMR and^13CNMR spectroscopy to confirm the structure spectroscopically. Spectra were recorded on a Varian Mercury Plus400 instrument. Spectra were recorded in DMSO. The following abbreviations are used to describe the peak shapes, when appropriate: s (singlet), d (doublet). Chemical shift is by Me₄Si as an internal standard. Mass spectrometry analysis of the synthesized product was performed on an applied Biosystem API 2000 mass spectrometer. Melting points were determined with a Kofler hot stage instrument and were not calibrated.

¹H NMR(DMSO)：δ7.03(d，1H)，7.31(d，2H)，7.32(s，1H)，7.71(d，1H)，7.97(d，1H)，9.55(s，NH₂)，9.91(s，NH₂)，10.25(s，-OH)；

¹³C NMR(DMSO)：δ114.4，119.5，122.1，122.7，129.2，129.5，138.1，152.1，157.7，165.9，189.7，199.7

MS(EI)，m/e 289(M⁺)；

m.p.：193-195℃。

Testing of Compounds

Example 19

Dosage of 4- (thio-5H- [1, 2] dithiol-3-yl) -phenyl 2-hydroxy-5-amino-benzoate hydrochloride (Compound XXXV) in TNBS-induced colitis in mice

Range study

In the following examples standard experimental animal models of colitis were used, wherein colitis was induced by intracolonic administration of 2, 4, 6-trinitrobenzenesulfonic acid (TNBS) to mice. A more detailed description of this model has been published (Santucci et al (2003) Gastroenterology 1241381-94), which is incorporated herein by reference. Briefly, a 1.5mg dose of TNBS in 0.1mL of 30% ethanol was administered intracolonically to 6-8 week old Balb/c mice. Mice were randomized into several treatment groups (n-6 per group). After the first 1 hour and continuing for 5 days every 12 hours, mice were treated orally with either the carrier (1% carboxymethylcellulose (CMC)), 5-ASA (mesalamine) (25, 50 or 75mg/kg) or an equivalent dose of 4- (thio-5H- [1, 2] dithiolen-3-yl) -phenyl 2-hydroxy-5-amino-benzoate hydrochloride (compound XXXV) (130mg/kg) or with 66% (100mg/kg), 50% (66mg/kg) and 25% (33mg/kg) of that dose. Mice were evaluated on the last day of the experiment for the presence of diarrhea and fecal occult blood and their body weights were determined. Based on these data, a "disease efficacy score" (0 to 4 points, marked on paper as described above) was calculated. After sacrifice, colonic samples were dissected to determine myeloperoxidase activity as a marker of granulocyte infiltration. All results were compared to results obtained from healthy mice.

The results of the disease efficacy score and MPO activity are shown in fig. 1 and fig. 2, respectively. Figure 1 shows that compound XXXV is superior to mesalazine in reducing activity scores at equivalent doses of 50mg/kg and 75 mg/kg. Furthermore, as shown in FIG. 2, MPO activity was significantly reduced (almost by half) at the highest dose tested.

Example 20

Compound XXXV with 5-ASA (mesalamine), ADT-OH and mesalamine alone

Comparison of disease Activity index and MPO Activity with mixtures of ADT-OH

FIGS. 3 and 4 show the disease activity index and MPO activity using the same colitis as described above in the experimental animal model, in which Compound XXXV (130mg/kg) was compared with an equivalent dose of a mixture of its two components, mesalamine (50mg/kg) and 5-p-hydroxyphenyl-1, 2-dithiole-3-thione (ADT-OH) (80mg/kg), and mesalamine (50mg/kg) and ADT-OH (80 mg/kg). P < 0.05 relative to vehicle-treated group. Each group contained at least 5 rats.

Figure 3 shows that compound XXXV is nearly 2-fold more potent than mesalamine alone, ADT-OH alone, or a mixture of mesalamine and ADT-OH in alleviating the symptoms of the disease. Furthermore, figure 4 shows that compound XXXV significantly reduced inflammation as indicated by reduced granulocyte penetration (reduced MPO activity).

Example 21

Comparison of the disease Activity index and MPO Activity of 5-amino-2- (4-Thiocarbamoyl-phenoxycarbonyloxy) -benzoic acid (Compound XXVII)

FIGS. 6 and 7 show the disease activity index and MPO activity using the same colitis as described above in the experimental animal model, in which Compound XXVII (100mg/kg) was compared with an equivalent dose of a mixture of the two components mesalamine (50mg/kg) and 4-hydroxythiobenzamide (4-HTB) (50mg/kg) and mesalamine (50mg/kg) alone and (4-HTB) alone (50 mg/kg). P < 0.05 relative to vehicle-treated group. Each group contained at least 5 rats.

Figure 5 shows that compound XXVII is nearly 3 times more potent than mesalamine alone, 4-HTB alone, or a mixture of mesalamine and 4-HTB in alleviating the symptoms of the disease. Furthermore, figure 6 shows that compound XXVII significantly reduced inflammation as indicated by reduced granulocyte penetration (reduced MPO activity).

Example 22

Effect of mesalazine and Compound XXXV on TNBS-induced colitis in mice

The same model as described above was used. In this example, the effect of mesalamine (50mg/kg) was compared with an equivalent dose of compound XXXV. In addition to determining the severity of colitis by disease efficacy score and MPO activity, tissues were treated to determine many genes for inflammatory cytokines and other mediators.

In particular, it is possible to use, for example, Wallace et al (1999) Gastroenterology 117: 557-566, the expression of mRNA in mouse tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), colonic Interleukin (IL) -1, IL-2, IL-10, IL-12, p40, RANTES, Cyclooxygenase (COX) -1, COX-2, constitutive endothelial nitric oxide synthase (eNOS), and Inducible NOS (iNOS) was determined and is incorporated herein by reference.

Briefly, reverse transcription-polymerase chain reaction (RT-PCR) is used to detect and quantify mRNA for specific cytokines/chemokines/enzymes. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as a "housekeeping gene" for mRNA expression (i.e., as an internal control). For each sample, the ratio of target gene amplification to GAPDH amplification was obtained (the expression of each was determined by densitometry on a gel). The relative amplification (expression) of the target gene in the tissue of the treatment group was then compared to the expression in the tissue of the healthy control group. Thus, the data shown in FIGS. 7-14 are representative of the relative expression of the target gene (normalized to GAPDH expression) as compared to the expression in the healthy control group.

From figures 7-14, it is noted that compound XXXV outperforms mesalamine at each endpoint. Of particular interest is that compound XXXV inhibits mRNA expression of several proinflammatory cytokines and chemokines involved in the pathogenesis of inflammatory bowel disease. However, compound XXXV does not inhibit the expression of the anti-inflammatory cytokine IL-10 mRNA.

In addition, compound XXXV inhibits COX-1 and COX-2 mRNA. COX-1 and COX-2 are involved in the synthesis of prostaglandins, which are important for inflammation. In addition, compound XXXV also inhibited eNOS and iNOS mRNA. Both eNOS and iNOS are associated with diseases of the GI tract.

Example 23

Compound XXXV and mesalamine in vitro inhibition of survival ability of HT-29 human colon cancer cells

Comparison of effects in force

HT-29 cells were grown in culture using standard methods. The cells are exposed to vehicle (DMSO), mesalamine, or compound XXXV. The concentration range tested was 0.1 to 10 μ M, each concentration tested in 6 wells. After 72 hours of exposure to the test drug, MTT [3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazoliumBromide compound]The assay (Carmichael et al (1978) Cancer Res.47, 936-942, incorporated herein by reference) measures the viability of cells. The ratio of cell viability was calculated as the percentage of vehicle (DMSO) -treated cells and the results are given in table 1.

TABLE 1

Concentration (μ M)

Medicine	0.1	1	10
				Mesalazine	103.8±2.5	101.2±3.5	91.1±3.2
XXXV	88.4±2.9**	87.3±2.3**	79.6±1.9**

P < 0.01 relative to mesalazine-treated group (same concentration)

Example 24

Comparison of the Effect of Compound XXXV with mesalazine in a rat model of visceral pain sensation

In the following examples, a rat model of visceral pain sensation, a preclinical model of irritable bowel syndrome, is used. Rats (male, Wistar, 200-250g, from Charles River, Monza, Italy) were placed in plastic cages and maintained under controlled conditions of 12 hours light/dark cycle with the lamp turned on at 7.00 AM. Tap water and standard laboratory food were taken ad libitum. Rats were trained in plexiglass cages for 2-3 hours each day for 2-3 days prior to the experiment. Which makes them adaptable to the restricted activity environment. Fasted 12 hours before colorectal distension (CRD) recordings. The experiments were performed in awake rats and in a double-blind fashion, with the observer unaware of the nature of the drug administered to each animal.

On the experimental day, the rats were sedated with ether inhalant, and a 2cm latex balloon 2cm long was inserted into the rectum from the hemorrhoid ring and fixed at the base of the tail. The balloon was connected to a pressure sensor via a double-barrel cannula to continuously monitor rectal pressure via a computer (PowerLab PC, a.d. instruments, Milford, MA, USA) and connected to a syringe for inflating/deflating the balloon. The rats were then placed in the protuberant Plexiglas^TMIn smaller cages (20X 8cm) on the platform and allowed to wake up and acclimate for 1 hour. After recovery from sedation, animals were subjected to the CRD procedure and tested for behavioral responses. The balloon was inflated overnight before the experiment and kept overnight to allow the latex to stretch and the balloon to become compliant.

CRD was performed every 5 minutes for 20 seconds, starting with 0.4ml of water and reaching 1.6ml of water in 0.4ml increments. To achieve accurate determination of colon parameters and sensations, 2 puffs were taken at each intensity and the data for each animal averaged for analysis. Each animal underwent two sets of CRDs. Drug (i.p.) was administered intraperitoneally 20 minutes after the first series of CRDs (0.4mL-1.6mL water), and a second series of CRDs was performed. Behavioral responses during the CRDs of the first and second sets were analyzed and compared.

Behavioral responses to CRD were evaluated by measuring the Abdominal Withdrawal Reflex (AWR) with a semi-quantitative score (1). AWR is an involuntary motor reflex similar to the visceral motor reflex, but it is of great benefit, in contrast to the latter, in that it does not require abdominal surgery in the abdominal muscles to implant recording electrodes and wires, which may lead to additional sensitization (see nest, t.j. and Gebhart, g.f. (1990) Pain 41: 167-.

The determination of AWR involves double blind observers visualizing the animal's response to graded CRD and the measurement of CRD according to Al-char, e.d. et Al (2000) Gastroenterology 19: 1276-85, wherein grade 0 corresponds to no behavioral response to CRD, grade 1 corresponds to brief head movements at the onset of stimulation after fixation, grade 2 corresponds to mild contraction of the abdominal muscles, however the rat does not lift the abdomen off the platform, grade 3 corresponds to strong contraction of the abdominal muscles with the abdomen lifted off the platform, and grade 4 corresponds to severe contraction of the abdominal muscles (manifested as body bowing and abdominal lifting) and severe contraction of pelvic structures and scrotum.

The effect of mesalazine and compound XXXV on colonic compliance and sensitivity was determined in a total of 8 fasted rats. To investigate whether administration of mesalamine and compound XXXV could restore CRD-induced pain, 4 rats were treated with mesalamine at a dose of 100mg/kg i.p. and compound XXXV at a dose of 100mg/kg i.p. after the first sequence of CRD, and then the CRD of the second group was repeated. The results of these tests are shown in FIGS. 15(a) and (b).

To determine the effect of mesalazine and compound XXXV on colon smooth muscle, colorectal compliance during CRD was obtained from colorectal internal volume and pressure and expressed as mL/mmHg. These results are shown in FIGS. 16(a) and (b).

All data are expressed as mean ± SEM, sample size is 4 rats/group; statistical comparisons of paired data were performed by Wilcoxon signed rank test. Correlation probabilities (p-values) of less than 5% were considered significant.

Figures 15(a) and (b) show that compound XXXV is more effective than mesalamine (and carrier) in reducing pain in response to colorectal distension. In addition, compound XXXV successfully reduced the intra-rectal pressure as shown in figure 16 (b).

Thus, compound XXXV has been shown to have potent anti-inflammatory activity, and may be used to treat various inflammatory conditions of the digestive tract, as well as functional gastrointestinal disorders characterized by increased visceral nociception (with or without inflammation), such as irritable bowel syndrome, dyspepsia, and the like.

Example 25

Pain scores for Compound XXXV and Compound XXVII with or without Glibenclamide

The rat model of visceral pain described above was used to compare the pain scores of compound XXXV and compound XXVII in the presence or absence of glibenclamide, an ATP-sensitive K⁺(K_ATP) An inhibitor of the channel.

FIG. 17 shows the pain perception score in response to colorectal distension of 0.8mL in groups of rats treated with vehicle, mesalamine (100mg/kg), compound XXXV (100mg/kg) or compound XXVII (100mg/kg), at least 5 per group. Compounds XXXV and XXVII significantly reduced pain sensation (p < 0.05 relative to vehicle treated group), while mesalazine had no significant effect. The reduction in pain perception by compound XXXV and compound XXVII can be reversed by pretreatment with glyburide (10mg/kg i.p., 30 minutes ago), which had no effect on pain perception in vehicle or mesalamine-treated groups, suggesting that the antinociceptive activity of compounds XXXV and XXVI I is due to ATP-sensitive K⁺(K_ATP) Channel-mediated.

Example 26

Comparison of pain perception scores for Compound XXXV and Compound XXVII with mesalazine

FIG. 19 shows the results of the test using the same pain model as described above. The effect of mesalazine (50mg/kg) treatment was compared with the effect of equivalent doses of compound XXXV (130mg/kg), ADT-OH (80mg/kg), compound XXVII (100mg/kg) and 4-HTB (50 mg/kg). Compound XXXV and compound XXVII alone significantly reduced pain sensation (./p < 0.05) when compared to vehicle treated groups.

Example 27

Effect of Compounds XXXV and XXVII on adhesion of leukocytes to vascular endothelium in vivo

Leukocyte adhesion was studied using biomicroscopy as previously detailed (Wallace et al, (1993) am. J. Physiol.265: 993-998, incorporated herein by reference). Rats were anesthetized with sodium pentobarbital (60mg/kg i.p.) and an incision was made along the abdomen for burns. A tracheotomy is performed to facilitate respiration. The rats were placed in a supine position and a section of mesentery was removed through the abdomen. The mesentery is carefully placed on an optically visible and clear base, 2cm for each section²Performing transillumination on the tissue. All exposed tissues were covered with saline-impregnated gauze to minimize dehydration. The temperature of the base was maintained at 37 ℃ and the mesentery was superfused with hot bicarbonate-buffered saline (pH 7.4). The microcirculation of the mesentery was observed with a live microscope (Nikon L25/0.35) and an x10 eyepiece. Posterior capillary venules of 20 to 40 μm in diameter were selected for study. Is arranged on a microscope (Panasonic)^TMdigital 5000) captured the image on the monitor, and the image was recorded with a video cassette recorder for playback analysis. Images of mesenteric microcirculation were recorded 5 minutes before aspirin (baseline), at the time of aspirin administration (times 0-5), and every 15 minutes (60 minutes total). From videotape images of the vessels obtained at 5 minutes, leukocyte adhesion was quantified double blindly in terms of the number of leukocytes, which remained fixed on the vessel wall (expressed per 100 μm microvia length) for 30 seconds or longer. Rats per group (at least 5 per group) were pretreated 60 minutes prior to aspirin (or vehicle) administration with compound XXXV (130mg/kg), compound XXVII (100mg/kg), mesalamine (50mg/kg), or vehicle. These drugs are administered intragastrically. In some experiments, glibenclamide was used 30 minutes prior to administration of these compounds(10mg/kg i.p.) or vehicle treated rats.

FIG. 19 shows leukocyte adhesion in response to intragastric aspirin administration, and the effects of these compounds. Aspirin significantly increased leukocyte adhesion relative to the amount observed during the baseline phase (p < 0.05 relative to the vehicle + vehicle group). Pretreatment with compound XXXV, but not with mesalazine, prevented aspirin-induced increases in leukocyte adhesion. Glibenclamide alone did not affect leukocyte adhesion, and did not affect the amount of aspirin-induced leukocyte adhesion. Glibenclamide also had no effect on the mesalazine + aspirin treatment group. However, glibenclamide reversed the inhibitory effect of compound XXXV on aspirin-induced leukocyte adhesion.

FIG. 20 shows leukocyte adhesion at the final time of the experiment (60-65 min). This figure demonstrates the ability of compound XXXV and compound XXVII to inhibit aspirin-induced leukocyte adhesion, and the ability of glyburide pretreatment to reverse the inhibition of leukocyte adhesion.

Example 28

From 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl 5-amino-2-hydroxy-benzoate (compound XXXV) and 4-or 5-amino-2- (4-thiocarbamoyl-phenoxy)

Carbonyloxy) -benzoic acid (referred to as Compound XXVII) to yield H₂S

Two compounds-Compound XXXV and Compound XXVII-H under three different conditions were tested₂S plays a role. Also measure H₂Concentration of S wherein H₂S is H derived from 1mM L-cysteine, Compound XXXV₂S-releasing moiety, ADT-OH (5- (4-amino-phenyl) - [1, 2]]Dithiole-3-thiones, Compound XXVII H₂S-releasing moiety, 4-HBT (4-hydroxythiobenzamide), was generated within 1 hour. Determination of H under three conditions₂S release: (i) when the compound is in a buffer(ii) when the compound is in liver homogenate, and (iii) when the compound is in liver homogenate and a cystathionine gamma-lyase inhibitor (PAG ═ DL-propargylglycine; 2 mM). The results are shown in FIG. 13. P < 0.05 compared to release from vehicle group. In comparison with the corresponding "homogenate" group,^φp is more than 0.05. Determination of H was carried out in the same reactor as described previously (Khan et al (1980) Microchem J.25: 388-₂Capacity of enzyme produced by S. 2ml of the analytical reaction mixture was introduced into the reactor. The mixture contained 1mM L-cysteine (or compound), 2mM pyridoxal 5' -phosphate, 100mM potassium phosphate buffer (pH 7.4). A constant flow of nitrogen gas was passed through the mixture through the inlet capillary. The reaction was started by transferring the tube from the ice bath to a 37 ℃ water bath. A nitrogen stream carries the sulfide acid into a second reactor containing 4ml of a sulfide antioxidant buffer (SAOB) solution, wherein the solution contains a pH of 12.8[5 ]]2M KOH, 1M salicylic acid and 0.22M ascorbic acid. After incubation at 37 ℃ for 90 minutes, the reaction was stopped by adding 1ml of 10% trichloroacetic acid solution to the mixture. The remaining H in the mixture was removed by incubation at 37 ℃ for a further 60 minutes under a stream of nitrogen₂And S. Using sulfide-sensitive electrodes (Model 9616S)^2-/Ag⁺Electrode, Orion Research, Beverly, MA, USA) to determine the concentration of sulfide in the SAOB solution. For the study of the test compounds cultured in liver homogenates, 100-150mg of isolated rat liver were homogenized in a 1ml ice-cold T-PER protein extractor. The homogenate was added to the reaction mixture at a concentration of 10% (wt/vol). DL-propargylglycine 2mM was incubated with the liver homogenate at 37 ℃ for 5 minutes before the enzyme reaction. Khan, s.u. morris, g.f. and Hidiroglou, m. (1980), Rapid evaluation of a refractory in rummena and a refractory-specific ion electrode. microchem j.25: 388- & 395, incorporated herein by reference.

The results in FIG. 21 show that the 4-or 5-ASA derivatives of the invention, in particular the compounds XXXV and XXVII, have the following outstanding features:

1. the derivative naturally releases H₂S (in buffer), the pairLocal action in the intestine is desirable. When cultured in buffer alone, H alone₂The S-releasing moiety, ADT-OH and 4-HTB, and L-cysteine did not release H significantly₂S；

2. When present in tissue, H₂The release of S is greater;

3.H₂the release of S from 4-or 5-ASA derivatives (rather than 4-or 5-amino-2-hydroxy-benzoic anhydride with N-acetylcysteine (formula X)) occurs independently of the endogenous synthesis of H₂The activities of the two major enzymes of S (cystathionine beta-synthase and cystathionine-gamma-lyase). This can be done by those enzymes (PAG; DL-propargylglycine) on H of compound XXXV and compound XXVII₂Lack of inhibition of S production. In contrast, PAG significantly inhibited H₂Release of S from L-cysteine;

4. h generated from Compound XXXV and Compound XXVII when 1mM Compound is used₂The concentration of S is 10-20 uM. Mesalamine concentrations measured in the colon cavity after patients take commonly used doses of the drug can be as high as 5mM mesalamine (dig. Dis. Sci.1989; 34: 573-578). H₂Endogenous concentrations of S can be as high as 160. mu.M (Artificial. RedoxSignal. 2003; 5, 493-501). H liberated from Compounds XXXV and XXVII₂The concentration of S is within the physiological range, thus leading to the formation of H₂S-related toxicity changes were minimal. However, it will be appreciated that when n-acetylcysteine is H₂S release moiety (compound of formula X) since more H is released from cysteine₂S, therefore lower doses will be used.

Example 29

H₂Vasodilation of S-releasing moiety

The following tests were carried out essentially as described in the following documents: bucci, M. et al (2004) diabetes mellitus and associated with a progressive to progressive systematic receiver deletion subunitMultiple to an enhanced caveolin-1expression, Arterioscler Thromb Vasc Biol 24-721 and 726, incorporated herein by reference. CD-1 mice were sacrificed and the thoracic aorta was rapidly dissected and fat and connective tissue removed. Rings 1.5-2mm long were cut out and fixed in a saturated vaporized Krebs solution (95% O) at 37 deg.c₂+5％CO₂) On a separate organ bath (Fort 10 World precision instruments, USA). Using PowerLab^TMThe data acquisition system (Ugo Basile, Italy) records the changes in the isotonic tension. The composition of the Krebs solution is as follows (mol/l): NaCl 0.118, KCl 0.0047, MgCl₂ 0.0012，KH₂PO₄ 0.0012，CaCl₂ 0.0025，NaHCO₃0.025 and glucose 0.010. The ring was initially stretched until a static tension of 1.5g was reached and allowed to equilibrate for at least 40 minutes to adjust the tension, reaching 1.5g when required, with periodic changes in bath solution. In preliminary studies, a resting tension of 1.5g was found to be the optimal tension for stimulation with the contractile agent.

In each experiment, the rings were normalized with L-Phenylephrine (PE) at 1. mu. mol/L until the response was reproducible. To evaluate the vasodilatory effect of the test compounds, cumulative concentration-response curve tests of the following compounds (10nM to 3mM) were performed on PE (1. mu.M) precontacted rings:

2, 4-bis (4-methoxyphenyl) -1, 3, 2, 4-dithiadiphosphetane 2, 4-disulfide (Lawesson's reagent), thioacetamide, NaHS, 4-HTB and Na₂And S. The carrier means buffer but no compound. The test compound profile was constructed in the presence of endothelium. To assess endothelial integrity, cumulative concentration-response curve assays for Ach (10nM-30 μ M) were performed on PE pre-contacted rings.

The data obtained are shown in FIG. 22 and expressed as mean. + -. SEM. By two-way analysis of variance (ANOVA) and subsequent use of GraphPad^TMThe software performed the Bonferroni test to achieve multiple comparisons to determine the level of statistical significance.

FIG. 22 shows the H of the present invention compared to the vector₂The S-releasing moieties, Lawesson' S reagent, 4-HTB and thioacetamide all showed significant vasodilatory effects, which were concentration dependent. In addition, the% relaxation curves were all comparable to using NaHS and Na₂The curve obtained at S is comparable.

Claims

1. A compound having the formula:

A-L-R (I)

wherein:

a is

wherein-NH₂In the 4 or 5-bit state,

l is O; and

r is a hydrogen sulfide releasing moiety selected from:

2. a compound according to claim 1, 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl 4-or 5-amino-2-hydroxy-benzoate.

3. The compound according to claim 1, 4-thiocarbamoylphenyl 4-or 5-amino-2-hydroxybenzoate.

4. A compound according to claim 1, 4- (5-thio-5H- [1, 2] dithiol-3-yl) -phenyl 5-amino-2-hydroxy-benzoate.

5. A compound according to claim 1, 4-thiocarbamoylphenyl 5-amino-2-hydroxybenzoate.

6. A pharmaceutical composition comprising a compound according to any one of claims 1 to 5, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient or carrier.

7. The use of a compound according to any one of claims 1 to 5 in the manufacture of a medicament for the treatment of inflammation of the gastrointestinal tract of a patient.

8. Use of a compound according to any one of claims 1 to 5 in the manufacture of a medicament for the treatment of crohn's disease in a patient.

9. Use of a compound according to any one of claims 1-5 in the manufacture of a medicament for treating ulcerative colitis in a patient.

10. Use of a compound according to any one of claims 1 to 5 in the manufacture of a medicament for the treatment of irritable bowel syndrome in a subject.

11. Use of a compound according to any one of claims 1 to 5 in the manufacture of a medicament for the prevention of colon cancer.