Hypoglycemic agents

Abstract

Provided is a method for treating hyperglycemia utilizing certain rhodanine derivatives. Certain of the rhodanine derivatives utilized in the instant method are novel and, accordingly, such compounds and pharmaceutical formulations thereof, are also provided.

Description

BACKGROUND OF THE INVENTION

Diabetes mellitus is a systemic disease characterized by disorders in the metabolism of insulin, carbohydrates, fats and proteins, and in the structure and function of blood vessels. The primary symptom of acute diabetes is hyperglycemia, often accompanied by glucosuria, the presence in urine of large amounts of glucose, and polyuria, the excretion of large volumes of urine. Additional symptoms arise in chronic or long standing diabetes. These symptoms include degeneration of the walls of blood vessels. Although many different organs are affected by these vascular changes, the eyes and kidneys appear to be the most susceptible. As such, long-standing diabetes mellitus, even when treated with insulin, is a leading cause of blindness.

There are two recognized types of diabetes. Type I diabetes is of juvenile onset, ketosis-prone, develops early in life with much more severe symptoms and has a near-certain prospect of later vascular involvement. Control of this type of diabetes is difficult and requires exogenous insulin administration. Type II diabetes mellitus is of adult onset, ketosis-resistant, develops later in life, is milder and has a more gradual onset.

One of the most significant advancements in the history of medical science came in 1922 when Batting and Best demonstrated the therapeutic effects of insulin in diabetic humans. However, even today, a clear picture of the basic biochemical defects of the disease is not known, and diabetes is still a serious health problem. It is believed that two percent of the United States' population is afflicted with some form of diabetes.

The introduction of orally effective hypoglycemic agents was an important development in the treatment of hyperglycemia by lowering blood glucose levels. Oral hypoglycemic agents are normally used in the treatment of adult onset diabetes.

A variety of biguanide and sulfonylurea derivatives have been used clinically as hypoglycemic agents. However, the biguanides tend to cause lactic acidosis and the sulfonylureas, though having good hypoglycemic activity, require great care during use because they frequently cause serious hypoglycemia and are most effective over a period of ten years.

In Chemical & Pharmaceutical Bulletin, 30, 3563 (1982), Chemical & Pharmaceutical Bulletin, 30, 3580 (1982) and Chemical & Pharmaceutical Bulletin, 32, 2267 (1984), reference is made to a variety of thiazolidinediones which have blood glucose and lipid lowering activities. Antidiabetic activity of ciglitazone was also reported in Diabetes, 32, 804 (1983). However, these compounds have proven difficult to use because of insufficient activities and/or serious toxicity problems.

The present invention relates to a series of hypoglycemic agents which are capable of lowering blood glucose levels in mammals. Accordingly, one object of the present invention is to provide compounds having excellent hypoglycemic activity. The hypoglycemic agents of the present invention are believed to have minimal toxicological effects. It is, therefore, believed that the compounds of the present invention may be very useful for treating diabetes. Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims.

SUMMARY OF THE INVENTION

The present invention provides a method of reducing blood glucose concentrations in mammals comprising administering a therapeutically effective amount of a compound of formula (I) ##STR1## wherein: Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.1 -C.sub.4 alkylphenyl, phenyl, NO.sub.2, F, Cl, hydroxy, phenoxy, C.sub.1 -C.sub.4 alkyloxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 1- or 2-naphthyl, (iv) 2- or 3-benzofuranyl, (v) 2- or 3-benzothiophenyl, (vi) 2-, or 3-thienyl, (vii) 2-, 3- or 4-pyridyl, (viii) 2- or 3-furanyl, (ix) 1,3-benzodioxanyl, (x) substituted 1,3-benzodioxanyl, (xi) quinolinyl, (xii) 2- or 3-indolyl or (xiii) N-substituted 2- or 3-indolyl;

R.sup.1 is C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkylphenyl, hydrogen, phenyl or phenyl substituted with one or two substituents independently selected from Cl, Br, F, I, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, hydroxy, trifluoromethyl, --NH.sub.2, --NH(C.sub.1 -C.sub.4 alkyl), --N(C.sub.1 -C.sub.4 alkyl).sub.2 or C.sub.1 -C.sub.4 alkylthio; R.sup.2 and R.sup.3 are each hydrogen or when taken together form a bond; R.sup.4 and R.sup.5 are each hydrogen or when taken together are =S, or when one of R.sup.4 and R.sup.5 is hydrogen, the other is --SCH.sub.3 ; R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, --SO.sub.2 CH.sub.3, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is cyano, --OR.sup.8, ##STR2## tetrazolyl, --NR.sub.10 R.sup.11, --SH, C.sub.1 -C.sub.4 alkylthio, or ##STR3## where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl or ##STR4## alkyl, R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, hydroxy or NH.sub.2, and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, C.sub.1 -C.sub.4 alkylphenyl, --(CH.sub.2).sub.q OH, --(CH.sub.2).sub.q N(C.sub.1 -C.sub.4 alkyl).sub.2, or --(CH.sub.2).sub.q S(C.sub.1 -C.sub.4 alkyl), where q is an integer from 1 to 6, both inclusive, or R.sup.10 and R.sup.11, taken together with the nitrogen atom to which they are attached, form a morpholinyl, piperidinyl, piperizinyl, or N-methylpiperazinyl ring; and m is 0, 1, or 2; with the provisos that Ar cannot be phenyl substituted solely with one chloro substituent at the 4-position of the phenyl ring; Ar cannot be phenyl substituted with a COOH moiety at the 2-position of the phenyl ring; when Ar is phenyl substituted with two ethoxy moieties at the 3- and 4-positions of the phenyl ring, R.sup.1 must be hydrogen; Ar cannot be phenyl substituted solely with two hydroxy substituents; and when R.sup.4 and R.sup.5 are each hydrogen, R.sup.6 cannot be C.sub.1 -C.sub.6 alkyl, or a pharmaceutically acceptable salt thereof, to a mammal in need of having its blood glucose concentration reduced.

Certain of the compounds which can be employed in the method of the present invention are novel. As such, the present invention also provides novel compounds of the formula (II) ##STR5## wherein: Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.2 -C.sub.4 alkylphenyl, NO.sub.2, F, Cl, phenoxy, C.sub.1 -C.sub.4 alkyloxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 .sup.R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 1- or 2-naphthyl, (iv) 2- or 3-benzofuranyl, (v) 2- or 3-benzothiophenyl, (vi) 2- or 3-thienyl, (vii) 2-, 3- or 4-pyridyl, (viii) 2- or 3-furanyl, (ix) 1,3-benzodioxanyl, (x) substituted 1,3-benzodioxanyl, (xi) quinolinyl, (xii) 2- or 3-indolyl or (xiii) N-substituted 2- or 3-indolyl;

R.sup.1 is C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkylphenyl, hydrogen, phenyl or phenyl substituted with one or two substituents independently selected from Cl, Br, F, I, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, hydroxy, trifluoromethyl, --NH.sub.2, --NH (C.sub.1 -C.sub.4 alkyl), --N(C.sub.1 -C.sub.4 alkyl).sub.2 or C.sub.1 -C.sub.4 alkylthio; R.sup.2 and R.sup.3 are each hydrogen or when taken together form a bond; R.sup.4 and R.sup.5 are each hydrogen or when taken together are .dbd.S, or when one of R.sup.4 and R.sup.5 is hydrogen, the other is --SCH.sub.3 ; R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, --SO.sub.2 CH.sub.3 or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is cyano, OR.sup.8, ##STR6## tetrazolyl, --NR.sup.10 R.sup.11, --SH, C.sub.1 -C.sub.4 alkylthio or ##STR7## where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl, or ##STR8## alkyl; R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, --(CH.sub.2).sub.q OH, --(CH.sub.2).sub.q N(C.sub.1 -C.sub.4 alkyl).sub.2, --(CH.sub.2).sub.q S(C.sub.1 -C.sub.4 alkyl), C.sub.2 -C.sub.6 alkynyl, phenyl, or C.sub.1 -C.sub.4 alkylphenyl, where q is 1 to 6, both inclusive, or R.sup.10 and R.sup.11, taken together with the nitrogen atom to which they are attached, form a morpholinyl, piperidinyl, piperazinyl or N-methylpiperazinyl ring; and m is 0, 1, or 2; with the provisos that when Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, F, Cl, trifluoromethyl, phenoxy, C.sub.1-C.sub.4 alkyloxyphenyl, C.sub.1 -C.sub.8 alkylthio, NO.sub.2, --N(R.sup.7).sub.2 or --COOR.sup.7, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 1- or 2-naphthyl, (iv) 2- or 3-benzofuranyl, (v) 2- or 3-benzothiophenyl, (vi) 2- or 3-thienyl, (vii) 2- or 3-indolyl, (viii) 2- or 3-furanyl, (ix) quinolinyl or (x) 2-, 3- or 4-pyridyl; R.sup.1 is hydrogen or C.sub.1 -C.sub.6 alkyl; R.sup.2 and R.sup.3 taken together form a bond; m is 0; and R.sup.4 and R.sup.5 taken together are .dbd.S, R.sup.6 must be other than hydrogen or C.sub.1 -C.sub.6 alkyl; when Ar is phenyl; R.sup.1 is hydrogen, methyl or ethyl; R.sup.2 and R.sup.3 taken together form a bond; m is 0; R.sup.4 and R.sup.5 taken together are .dbd.S; R.sup.6 must be other than phenyl or C.sub.1 -C.sub.4 alkylphenyl; Ar cannot be phenyl substituted solely with one chloro substituent at the 4-position of the phenyl ring; when Ar is phenyl substituted with two ethoxy moieties at the 3- and 4-positions of the phenyl ring, R.sup.1 must be hydrogen; Ar cannot be phenyl substituted with a COOH moiety at the 2-position of the phenyl ring; and when R.sup.4 and R.sup.5 are each hydrogen R.sup.6 cannot be C.sub.1 -C.sub.6 alkyl, and the pharmaceutically acceptable salts thereof.

In addition to the genus of novel compounds described by formula II, above, certain other of the compounds which can be employed in the method of the present invention also appear to be novel. These compounds, while structurally similar to compounds specifically known in the art (see, for example, European Patent Application Nos. 343643, 391644 and 39817 as well as U.S. Pat. No. 4,552,891 , are not actually described in any of those patents or applications. As such, the present invention also encompasses the following novel compounds and their pharmaceutically acceptable salts:

5-[(2-nitrophenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(4-fluorophenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(2-thienyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(2-furanyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3,4,5-trimethoxyphenyl)methylmethylene]-2-thioxo-4-thiazolidinone; 4-[(2-thioxo-4-thiazolidinone)methylene]benzoic acid; 5-[(3-hydroxy-4-nitrophenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-hydroxyphenyl)methylmethylene]-2-thioxo--thiazolidinone; 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-hydroxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-ethoxy-4-propoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-propoxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3,4-dipropoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxy-phenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid; 5-[(3,5-dichloro-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-ethoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-ethoxy-4-methoxyphenyl)methylene ]-2-thioxo-4-thiazolidinone; 5-[[3,5-bis (1-methylpropyl)hydroxyphenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid; 5-[(4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-3-methyl-4-thiazolidinone; 5-[(3-methoxy-4-octoxyphenyl)methylene ]-2-thioxo-4-thiazolidinone; 5-[(3,5-dimethoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[[3-(1,1-dimethylethyl)-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-2-thioxo-4-thiazolidinone; 5-[[3-ethoxy-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-2-thioxo-4-thiazolidinone; 5-[[3-ethoxy-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-2-thioxo-3-methyl-4-thiazolidinone; 5-[[3-ethoxy-4-hydroxy-5-(methylthiotphenyl)phenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid.

Certain of the above compounds and, in particular, 5-[(4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-propoxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-ethoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid; and 5-[[3,5-bis(1-methylpropyl)-4-hydroxyphenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid (especially the latter three compounds), appear to possess a surprising ability to lower blood glucose levels in mammals compared to structurally similar compounds known in the art. Because of such surprising activity, these compounds are particularly preferred compounds of the present invention.

Finally, the present invention also provides pharmaceutical formulations comprising a compound of the present invention, or a pharmaceutically acceptable salt thereof, in combination with a pharmaceutically. acceptable carrier, diluent or excipient therefor.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "C.sub.1 -C.sub.8 alkyl" represents a straight or branched alkyl chain having from one to eight carbon atoms. Typical C.sub.1 -C.sub.8 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, and the like. The term "C.sub.1 -C.sub.8 alkyl" includes within its definition the terms "C.sub.1 -C.sub.4 alkyl" and "C.sub.1 -C.sub.6 alkyl".

"C.sub.1 -C.sub.4 alkylphenyl" represents a straight or branched chain alkyl group having from one to four carbon atoms attached to a phenyl ring. Typical C.sub.1 -C.sub.4 alkylphenyl groups include methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, and tert-butylphenyl.

The term "C.sub.1 -C.sub.4 alkylthiophenyl" represents a straight or branched chain alkyl group having from one to four carbon atoms attached to a thiophenyl moiety. Typical C.sub.1 -C.sub.4 alkylthiophenyl groups include methylthiophenyl, ethylthiophenyl, isobutylthiophenyl and the like.

In a similar fashion, the term "C.sub.1 -C.sub.4 alkyloxyphenyl" represents a straight or branched chain alkyl group having from one to four carbon atoms attached to phenoxy moiety. Typical C.sub.1 -C.sub.4 alkyloxyphenyl groups include methyloxyphenyl, ethyloxyphenyl, propyloxyphenyl and the like.

"C.sub.1 -C.sub.8 alkoxy" represents a straight or branched alkyl chain having one to eight carbon atoms, which chain is attached to the remainder of the molecule by an oxygen atom. Typical C.sub.1 -C.sub.8 alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, hexoxy, heptoxy, and the like. The term "C.sub.1 -C.sub.8 alkoxy" includes within its definition the term "C.sub.1 -C.sub.4 alkoxy".

"C.sub.1 -C.sub.8 alkylthio" represents a straight or branched alkyl chain having one to eight carbon atoms, which chain is attached to the remainder of the molecule by a sulfur atom. Typical C.sub.1 -C.sub.8 alkylthio groups include methylthio, ethylthio, propylthio, butylthio, tert-butylthio, octylthio and the like. The term "C.sub.1 -C.sub.8 alkylthio" includes within its definition the term "C.sub.1 -C.sub.4 alkylthio".

The term "C.sub.2 -C.sub.6 alkenyl" refers to straight and branched chain radicals of two to six carbon atoms, both inclusive, having a double bond. As such, the term includes ethylene, propylene, 1-butene, 2-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-2-butene and the like.

The term "C.sub.2 -C.sub.6 alkynyl" refers to straight and branched chain radicals of two to six carbon atoms, both inclusive, having a triple bond. As such, the term includes acetylene, propyne, 1-butyne, 2-hexyne, 1-pentyne, 3-ethyl-1-butyne and the like.

The term "C.sub.3 -C.sub.8 cycloalkyl" refers to saturated alicyclic rings of three to eight carbon atoms, both inclusive, such as cyclopropyl, methylcyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl and the like.

The terms "1,3-benzodioxanyl" and "substituted 1,3-benzodioxanyl" refer to structures of the formulae ##STR9## where each R is independently hydrogen or C.sub.1 -C.sub.4 alkyl.

"Quinolinyl" refers to a quinoline ring system which is attached to the rest of the molecule at the 4, 5, 6, 7 or 8 position of such ring system.

"N-substituted 2- or 3-indolyl" refers to a 2- or 3-indolyl ring system substituted on the nitrogen atom of that ring system with a C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkylphenyl, or C.sub.3 -C.sub.8 cycloalkyl group.

The term "pharmaceutically acceptable salts" refers to salts of the compounds of the above formulae which are substantially non-toxic to living organisms. Typical pharmaceutically acceptable salts include those salts prepared by reaction of the compounds of the above formulae with a pharmaceutically acceptable mineral or organic acid, or a pharmaceutically acceptable alkali metal or organic base, depending on the types of substituents present on the compounds of the formulae.

Examples of pharmaceutically acceptable mineral acids which may be used to prepare pharmaceutically acceptable salts include hydrochloric acid, phosphoric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, phosphorous acid and the like. Examples of pharmaceutically acceptable organic acids which may be used to prepare pharmaceutically acceptable salts include aliphatic mono and dicarboxylic acids, oxalic acid, carbonic acid, citric acid, succinic acid, phenyl-substituted alkanoic acids, aliphatic and aromatic sulfonic acids and the like. Such pharmaceutically acceptable salts prepared from mineral or organic acids thus include hydrochloride, hydrobromide, nitrate, sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, hydroiodide, hydrofluoride, acetate, propionate, formate, oxalate, citrate, lactate, p-toluenesulfonate, methanesulfonate, maleate, and the like.

Many compounds of formula I or II which contain a carboxy, carbonyl, hydroxy or sulfoxide group may be converted to a pharmaceutically acceptable salt by reaction with a pharmaceutically acceptable alkali metal or organic base. Examples of pharmaceutically acceptable organic bases which may be used to prepare pharmaceutically acceptable salts include ammonia, amines such as triethanolamine, triethylamine, ethylamine, and the like. Examples of pharmaceutically acceptable alkali metal bases included compounds of the general formula MOR.sup.13, where M represents an alkali metal atom, e.g. sodium, potassium, or lithium, and R.sup.13 represents hydrogen or C.sub.1 -C.sub.4 alkyl.

It should be recognized that the particular anion or cation forming a part of any salt of this invention is not critical, so long as the salt, as a whole, is pharmacologically acceptable and as long as the anion or cationic moiety does not contribute undesired qualities.

A preferred genus of compounds useful in the instantly claimed method of reducing blood glucose concentrations includes those compounds wherein Ar, R.sup.1, R.sup.2, R.sup.3, m, R.sup.4, and R.sup.5 are as set forth for formula I, and R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, --SO.sub.2 CH.sub.3 or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is cyano, --OR.sup.8, ##STR10## tetrazolyl, NR.sup.10 R.sup.11, --SH, --S(C.sub.1 -C.sub.4 alkyl), or ##STR11## where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl, or ##STR12## alkyl, R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl, or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, C.sub.1 -C.sub.4 alkylphenyl, --(CH.sub.2).sub.q OH, --(CH.sub.2).sub.q N (C.sub.1 -C.sub.4 alkyl).sub.2, or --(CH.sub.2 ).sub.q S(C.sub.1 -C.sub.4 alkyl) where q is 1 to 6, both inclusive, or R.sup.10 and R.sup.11, taken together with the nitrogen atom to which they are attached, form a morpholinyl, piperidinyl, piperazinyl, or N-methylpiperazinyl ring

Of this preferred genus, those compounds in which m is 0 are more preferred.

Of this more preferred genus, those compounds in which R.sup.4 and R.sup.5 taken together are .dbd.S are even more preferred.

Of this even more preferred genus, those compounds in which R.sup.1 is hydrogen are especially preferred.

Of this especially preferred genus, those compounds in which R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is --OR.sup.8, ##STR13## --NR.sup.9, --NR.sup.10 R.sup.11, or C.sub.1 -C.sub.4 alkylthio, where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl or ##STR14## alkyl, R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, or C.sub.1 -C.sub.4 alkylphenyl are particularly preferred.

Of this particularly preferred genus, those compounds in which R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, or C.sub.2 -C.sub.6 alkenyl are more particularly preferred.

Of this more particularly preferred genus, those compounds in which Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.1 -C.sub.4 alkylphenyl, phenyl, NO.sub.2, F, Cl, hydroxy, phenoxy, C.sub.1 -C.sub.4 alkyloxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 2-, 3- or 4-pyridyl, or (iv) 2- or 3-furanyl are substantially preferred.

Of this substantially preferred genus, those compounds wherein Ar is phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.4 alkylphenyl, phenyl, NO.sub.2, F, Cl, hydroxy, phenoxy, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7 or --N(R.sup.7)SO.sub.2 R.sup.7, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, are more substantially preferred.

Of this more substantially preferred genus, those compounds wherein Ar is phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl (especially C.sub.1 -C.sub.4 alkyl), C.sub.1 -C.sub.8 alkoxy (especially C.sub.1 -C.sub.6 alkoxy), or hydroxy are even more substantially preferred.

The most preferred compounds which may be employed in the method of the present invention include 5-[(3,4-diethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-methoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, sodium salt; 5-[(3-methoxy-4-pentoxyphenyl)methyl]-2-thioxo-4-thiazolidinone; 5[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene]-2-thioxo-4-thiazolidinone; 5[(3,5-dimethyl-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone and 5-[(3,5-dimethoxy-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone.

A preferred genus of compounds of the present invention includes those compounds wherein Ar, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as set forth for Formula II, and m is 0. Of this preferred genus, those compounds in which R.sup.4 and R.sup.5 taken together are .dbd.S are more preferred. Of this more preferred genus, those compounds in which R.sup.2 and R.sup.3 taken together form a bond are especially preferred.

Of this especially preferred genus, those. compounds in which R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is --OR.sup.8, ##STR15## --NR.sup.10 R.sup.11, or C.sub.1 -C.sub.4 alkylthio, where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl or ##STR16## alkyl, R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, or C.sub.1 -C.sub.4 alkylphenyl are particularly preferred.

Of this particularly preferred genus, those compounds in which R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, or C.sub.2 -C.sub.6 alkenyl are more particularly preferred. Of this more particularly preferred genus, those compounds in which R.sup.1 is hydrogen or phenyl are even more particularly preferred.

Of this even more particularly preferred genus, those compounds in which Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.2 -C.sub.4 alkylphenyl, NO.sub.2, F, Cl, phenoxy, C.sub.1 -C.sub.4 alkoxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 1,3-benzodioxanyl,(iv) substituted 1,3-benzodioxanyl or (v) quinolinyl are substantially preferred compounds.

Of this substantially preferred genus, those compounds wherein Ar is (i) phenyl substituted with from one to three of phenoxy or --N(R.sup.7)SO.sub.2 R.sup.7, where each R.sup.7 is hydrogen or C.sub.1 -C.sub.6 alkyl or (ii) 1,3-benzodioxanyl are more substantially preferred.

Certain preferred compounds of the present invention include 5-(diphenylmethylene)-2-thioxo-4-thiazolidinone; 5-[(1,3-benzodioxol-5-yl)methylene)-2-thioxo-4-thiazolidinone; 5-[(4-phenoxyphenyl)methylene]-2-thioxo-4-thiazolidinone; and 5[(3-methanesulfonamidophenyl)methylene]-2-thioxo-4-thiazolidinone.

An alternative preferred genus of compounds of the present invention includes those compounds wherein Ar, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and m are as defined for formula II, and R.sup.6 is C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, --SO.sub.2 CH.sub.3 or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is cyano, --OR.sup.8, ##STR17## tetrazolyl, --NR.sub.10 R.sup.11, --SH, C.sub.1 -C.sub.4 alkylthio, or ##STR18## where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl, or ##STR19## alkyl; R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl, or NH.sub.2 ; and R.sup. 10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, C.sub.1 -C.sub.4 alkylphenyl, --(CH.sub.2).sub.q OH, --(CH.sub.2).sub.q N(C.sub.1 -C.sub.4 alkyl).sub.2, or --(CH.sub.2).sub.q S(C.sub.1 -C.sub.4 alkyl) where q is 1 to 6, both inclusive, or R.sup. 10 and R.sup.11, taken together with the nitrogen atom to which they are attached, form a morpholinyl, piperidinyl, piperazinyl, or N-methylpiperazinyl ring.

Of this preferred genus, those compounds in which m is 0 are more preferred.

Of this more preferred genus, those compounds in which R.sup.4 and R.sup.5 taken together are =S are even more preferred.

Of this even more preferred genus, those compounds in which R.sup.2 and R.sup.3 taken together form a bond are especially preferred

Of this especially preferred genus, those compounds in which R.sup.6 is C.sub.2 -C.sub.6 alkenyl, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is --OR.sup.8, ##STR20## --NR.sup.10 R.sup.11, or C.sub.1 -C.sub.4 alkylthio, where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl or ##STR21## alkyl R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, or C.sub.1 -C.sub.4 alkylphenyl are particularly preferred.

Of this particularly preferred genus, those compounds wherein R.sup.1 is hydrogen or phenyl are more particularly preferred.

Of this more particularly preferred genus, those compounds in which Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.2 -C.sub.4 alkylphenyl, NO.sub.2, F, Cl, phenoxy, C.sub.1 -C.sub.4 alkoxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl (iii) 2-, 3- or 4-pyridyl, or (iv) 2- or 3-furanyl are even more particularly preferred.

Of this even more particularly preferred genus, those compounds wherein Ar is phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.2 -C.sub.4 alkylphenyl, NO.sub.2, F, Cl, phenoxy, C.sub.1 -C.sub.4 alkoxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, are substantially preferred.

Of this substantially preferred genus, those compounds wherein Ar is phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl or C.sub.1 -C.sub.8 alkoxy are most preferred.

The present invention also encompasses formulations comprising a compound of the present invention in combination with a pharmaceutically acceptable carrier, diluent, or excipient therefor. Preferred formulations of the present invention are those formulations which contain a preferred compound or genus of compounds of the present invention, as described above.

The following examples illustrate the preparation of the compounds of this invention. The examples are illustrative only and are not intended to limit the scope of the invention in any way.

The compounds of the present invention, as well as the compounds employed in the method of the present invention, can, typically, be prepared by methods well known to one skilled in the art of organic chemistry. For example, such compounds may be prepared by condensation of rhodanine, or an appropriately substituted rhodanine derivative, with an appropriately substituted aromatic aldehyde or aldehyde derivative such as a mono or disubstituted imine of the formula ##STR22## or ##STR23## Such reaction is illustrated utilizing an appropriately substituted aromatic aldehyde as follows ##STR24## where Ar and R.sup.6 are as defined in formulae I and II.

Compounds of the present invention (as well as those compounds employed in the method of the present invention) wherein R.sup.2 and R.sup.3 are hydrogen, or when taken together form a bond, and R.sup.4 and R.sup.5 are each hydrogen can be prepared by subjecting the compound wherein R.sup.4 and R.sup.5 taken together form .dbd.S to catalytic hydrogenation. The relative proportions of compound obtained (R.sup.2, R.sup.3, R.sup.4 and R.sup.5 all hydrogen vs. R.sup.2 and R.sup.3 taken together form a bond and R.sup.4 and R.sup.5 are hydrogen) depends upon the temperature, pressure, and duration of hydrogenation, the solvent employed and the particular catalyst used. Alternatively, the above transformations may be accomplished by heating the compounds wherein R.sup.4 and R.sup.5 taken together are .dbd.S and R.sup.2 and R.sup.3 taken together are a double bond in a mixture of hydrochloric acid and an alcohol, such as ethanol, in the presence of zinc. Reduction of the thione without affecting the benzylic double bond may be accomplished by heating the thione with a reducing agent such as tri-n-butyl tin hydride in a non-reactive solvent, such as toluene, and preferably in the presence of a free radical initiator, such as azobisisobutyronitrile. However, for such reduction to work, an N-substituted rhodanine substrate must be employed.

The transformation of compounds wherein R.sup.2 and R.sup.3. taken together form a bond and R.sup.4 and R.sup.5 taken together are .dbd.S to those compounds wherein R.sup.2 and R.sup.3 are both hydrogen while R.sup.4 and R.sup.5 remain unchanged may be accomplished by treating the unsaturated compound with a dihydropyridine, such as diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridine dicarboxylate in the presence of silica gel. The reaction is best carried out in the presence of a nonreactive solvent such as benzene or toluene, preferably under an inert atmosphere. The reaction may be accomplished at temperatures from about 25.degree. C. up to the reflux temperature of the mixture. At the preferred temperature of approximately 80.degree. C., the reaction is essentially complete after about 12-18 hours.

Compounds of formulae I or II wherein R.sup.1 is C.sub.1 -C.sub.6 alkyl, phenyl, a substituted phenyl of the type described above, or C.sub.1 -C.sub.4 alkylphenyl may be prepared by conventional Friedel-Crafts acylation of an appropriately substituted aromatic compound with an acyl halide of the formula R.sup.1 --C(O)--X, wherein R.sup.1 is as defined in formulae I or II and X is chloro, fluoro, bromo or iodo. The resulting aromatic ketone is then condensed with rhodanine, or an appropriately substituted rhodanine derivative.

The compounds of the present invention (as well as the compounds employed in the method of the present invention) allow various R.sup.6 substituents. These R.sup.6 substituents can be prepared as follows.

Compounds of formulae I and II wherein R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl or --(CH.sub.2).sub.p --Y where p is as defined for formulae I and II and Y is cyano, or NR.sup.10 R.sup.11 where R.sup.10 and R.sup.11 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl may be prepared using the method set forth in the above reaction scheme. Alternatively, rhodanine may be used for condensation with an aldehyde or aldehyde derivative forming those species wherein R.sup.6 is hydrogen, followed by alkylation or acylation with the appropriate R.sup.6 -containing halide. The alkylation or acylation is usually accomplished in an inert solvent such as tetrahydrofuran or dimethylformamide and in the presence of a strong base such as sodium hydride.

Alternatively, compounds of formulae I and II wherein R.sup.6 is --(CH.sub.2).sub.p --Y where Y is cyano may be prepared by treating the non-cyanated analog with a halo-substituted aliphatic nitrile. From this cyano derivative the tetrazolyl is prepared as by treatment with tri-N-butyl tin azide in, for example, ethylene glycol dimethyl ether.

Compounds of formulae I and II wherein R.sup.6 is --(CH.sub.2).sub.p --Y (p=0) and Y is NR.sup.10 R.sup.11, where R.sup.10 and R.sup.11 are as defined in formulae I and II, may also be prepared by employing an appropriately substituted hydrazine. In this reaction sequence, benzaldehyde is reacted with an appropriately substitued hydrazine, in an alcoholic solvent, yielding III. An appropriately substituted alkyl halide is then reacted with III, in the presence of triethylamine and acetonitrile, to provide IV, which is then further reacted with hydrazine to yield the R.sup.10, R.sup.11 hydrazine V. Compound V may alternatively be prepared by the reduction of a nitroso-R.sup.10 R.sup.11 amine using zinc dust and acetic acid or aluminum and a strong base. The R.sup.10, R.sup.11 hydrazine is then treated with carbon disulfide, chloroacetic acid and triethylamine to provide intermediate VI. Condensation of VI with an appropriately substituted aromatic aldehyde or aldehyde derivative yields the desired product, as represented by the following reaction scheme. ##STR25##

Furthermore, the thione portion of the compound produced above may be reduced by treatment with a reducing agent such as tri-n-butyltin hydride in an inert solvent such as toluene, preferably in the presence of a free radical initiator such as azobisisobutyronitrile. Preparation of compounds wherein one of R.sup.10 and R.sup.11 is hydrogen may be effected before or after reduction of the thione, as desired, by heating the disubstituted compound in a mixture of ethanol/water in the presence of a catalyst such as a rhodium catalyst.

Compounds of formulae I and II wherein R.sup.6 is --(CH.sub.2).sub.p --Y and Y is OR.sup.8 or NR.sup.10 R.sup.11 (where R.sup.8 is hydrogen, acetyl or tosyl and R.sup.10 and R.sup.11 are each independently hydrogen or C.sub.1 -C.sub.6 alkyl) may also be prepared according to the following reaction scheme: ##STR26##

A hydroxyalkyl rhodanine is prepared by condensing carbon disulfide, chloroacetic acid, and the appropriate hydroxyalkylamine by standard techniques. When condensed with the appropriately substituted aromatic aldehyde (or aldehyde derivative), as described above, the resulting product is the condensed 2-thioxo-4-thiazolidinone VIII which has been transformed into the acetyl derivative. The thioxo compound VIII may optionally be converted to the methylene compound of formulae I or II as described above. The acetyl group of intermediate IX may be removed upon treatment with aqueous ammonia in a solvent such as acetonitrile to provide Compound X. The hydroxy compound X is then converted to the tosyl derivative upon treatment with p-toluenesulfonyl chloride in pyridine, preferably at temperatures of around 0.degree. C. The versatile tosyl intermediate XI may then be transformed into the compounds of formulae I or II upon treatment with an appropriate HNR.sup.10 R.sup.11 amine. This latter transformation is best accomplished by allowing XI to react in the presence of a molar excess of the amine. Once again, a solvent such as acetonitrile is useful for accomplishing this transformation.

Those compounds where m is 1 or 2 are readily prepared from the sulfide (m=0) by treatment with an oxidizing agent, such as m-chloroperbenzoic acid, in a suitable solvent for a time sufficient to generate the desired oxidative state.

Depending upon the definitions of R.sup.1, R.sup.2, and R.sup.3, the compounds of formulae I and II may exist in various isomeric forms. The compounds, formulations and methods of the present invention are not related to any particular isomer but include all possible isomers and racemates.

It will be readily appreciated by one skilled in the art that the aromatic portion of the compounds of the invention (or the compounds employed in the method of the present invention) can be provided by compounds which are either commercially available or may be readily prepared by known techniques from commercially available starting materials. Similarly, the rhodanine or N-substituted rhodanine starting material is either commercially available or may be prepared by well known methods from commercially available substrates.

The following Examples illustrate the preparation of the compounds of the present invention, as well as compounds which may be employed in the method of the present invention. The Examples are illustrative only and are not intended to limit the scope of the instant invention in any way.

EXAMPLE 1

5-[(3-methanesulfonamidophenyl)methylene]-2-thioxo-4-thiazolidinone

Thirty seven grams (185.9 mmol) of 3-methanesulfonamidbenzaldehyde, 25.0 g (187.9 mmol) of rhodanine, 48.0 g (585.3 mmol) of anhydrous sodium acetate and 950 ml of acetic acid were stirred while heating at reflux for 20 hours. The reaction was then stirred at room temperature for approximately another 60 hours. The resulting slurry was poured into 3000 ml of a 1:1 ethanol/water mixture. Solids precipitated and were recovered by filtration, washed with water and then vacuum dried to provide 54 g of title compound. m.p. 260.degree.-265.degree. C.

Analysis for C.sub.11 H.sub.10 N.sub.2 O.sub.3 S.sub.3 Calculated: C, 42.02; H, 3.20; N 8.91; Found: C, 42.15; H, 3.57; N 8.71.

EXAMPLE 2

5-[(1,3-benzodioxol-5-yl)methylene]-2-thioxo-4-thiazolidinone

Twenty grams (133.2 mmol) of piperonal were reacted with 17.74 g (133.2 mmol)of rhodanine in 38.24 g (466.2 mmol) of glacial acetic acid at reflux for about 3 hours. The mixture was then poured into water and stirred overnight. A precipitate formed which was recovered by filtration and then air dried overnight to provide 27.8 g of title product. m.p. 194.degree.-195.degree. C. Analysis for C.sub.11 H.sub.7 N.sub.1 O.sub.3 S.sub.2 : Calculated: C, 49.80; H, 2.66; N 5.28; S, 24.17; Found: C, 50.04; H, 2.38; N 5.27; S, 23.98.

EXAMPLE 3

5-[(4-quinolinyl)methylene]-2-thioxo-4-thiazolidinone

Rhodanine (2.2 g; 16.5 mmol), 1.3 ml of concentrated ammonium hydroxide and 1 g of ammonium chloride in 20 ml of ethanol were heated on a steam bath for 15 minutes. 4-Quinoline carboxaldehyde (2.6 g; 16.5 mmol) was added and the resulting mixture was heated on the steam bath for another hour. Upon cooling to 5.degree. C. a precipitate formed. This precipitate was recovered by filtration and then washed with water to provide 4 g of title compound, m.p. 325.degree.-328.degree. C.

Analysis for C.sub.13 H.sub.8 N.sub.2 OS.sub.2 : Calculated: C, 57.33; H, 2.96; N 10.29; Found: C, 57.11; H, 3.11; N 10.21.

EXAMPLE 4

5-(diphenylmethylene)-2-thioxo-4-thiazolidinone

One hundred and ninety grams (1.05 mol) of diphenyl ketimine, 140 grams (1.05 mol) of rhodanine, 5 ml of acetic acid and 1500 ml of toluene were heated at reflux for 3 hours. Crystals formed upon cooling. The solvent was decanted, fresh toluene was added to the residue and the resulting suspension was filtered. The recovered crystals were recrystallized from methanol to provide 172.0 g of title product, m.p. 192.degree.-194.degree. C.

Analysis for C.sub.16 H.sub.11 NOS.sub.2 : Calculated: C, 64.62; H, 3.73; 0, 5.38; N 4.71; S, 21.56; Found: C, 64.13; H, 3.84; 0, 5.57; N 4.59; S, 22.38.

EXAMPLE 5

5-[(4-phenoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

A mixture of 9.9 g (50.0 mmol) of 4-phenoxybenzaldehyde, 6.8 g (51.1 mmol) of rhodanine, 15.5 g of sodium acetate and 60 ml of acetic acid was heated on a steam bath for two hours. The reaction solution was then poured into water causing crude product to precipitate. The precipitate was filtered and then washed successively with water followed by diethyl ether to provide 8.6 g of title product, m.p. 195.degree.-200.degree. C.

Analysis for C.sub.16 H.sub.11 NO.sub.2 S.sub.2 : Calculated: C, 61.32; H, 3.54; N 4.47; Found: C, 61.07; H, 3.63; N 4.47.

The following compounds were synthesized using methods substantially equivalent to those described in Examples 1-5 above or as described elsewhere herein.

EXAMPLE 6

5-(phenylmethylene)-2-thioxo-4-thiazolidinone, m.p. 202.degree.-203.5.degree. C.

EXAMPLE 7

5-[(2-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 220.degree.-222.degree. C.

EXAMPLE 8

5-[(4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 287.degree.-290.degree. C.

EXAMPLE 9

5-[(2-nitrophenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 197.5.degree.-199.degree. C.

EXAMPLE 10

5-[(3-nitrophenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 277.degree.-280.degree. C.

EXAMPLE 11

5-[(3-hydroxyphenyl)methylene ]-2-thioxo-4-thiazolidinone, m.p. 242.degree.-244.degree. C.

EXAMPLE 12

5-[(2,4-dimethoxyphenyl)methylene ]-2-thioxo-4-thiazolidinone, m.p. 253.degree.-255.degree. C.

EXAMPLE 13

5-[(4-fluorophenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 225.degree.-227.degree. C.

EXAMPLE 14

5-[(2-thienyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 231.degree.-233.degree. C.

EXAMPLE 15

5-[(2-furanyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 217.degree.-219.degree. C.

EXAMPLE 16

5-[(4-pyridyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 297.degree.-298.degree. C.

EXAMPLE 17

5-[(3,4,5-trimethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 203.degree.-205.degree. C.

EXAMPLE 18

5-[(4-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 252.degree.-254.degree. C.

EXAMPLE 19

5-[(3,4,5-trimethoxyphenyl)methylmethylene]-2-thioxo-4-thiazolidinone, m.p. 210.degree.-213.degree. C.

EXAMPLE 20

5-[(3-methoxy-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 229.degree.-231.degree. C.

EXAMPLE 21

5-[(4-methoxyphenyl)phenylmethylene]-2-thioxo-4-thiazolidinone, m.p. 169.degree.-171.degree. C.

EXAMPLE 22

5-[(3-pyridyl)methylene]-2-thioxo-4-thiazolidinone, m.p. .about.286.degree. C.

EXAMPLE 23

5-[(3-chlorophenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 233.degree.-235.degree. C.

EXAMPLE 24

5-[(2,3-dimethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 25

5-[(3-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 26

5-[(2-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 27

5-[(3-methyl-4-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 28

5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene]-2-thioxo-4-thiazolidinone, .about.260.degree. C.

EXAMPLE 29

5-[(1,1'-biphenyl]-2-yl)methylene)-2-thioxo-4-thiazolidinone

EXAMPLE 30

5-[(3-methoxy-4-hydroxyphenyl)methylene ]-3-(2-propenyl)-2-thioxo-4-thiazolidinone, m.p. 146.degree.-148.degree. C.

EXAMPLE 31

5-[(3-methoxy-4-heptoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 130.degree.-132.degree. C.

EXAMPLE 32

5-[(3-ethoxy-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 217.degree.-217.5.degree. C.

EXAMPLE 33

5-[(3-methylphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 197.degree.-202.degree. C.

EXAMPLE 34

5-[(4-methylphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 229.degree.-234.degree. C.

EXAMPLE 35

5-[(2-naphthalenyl)methylene)-2-thioxo-4-thiazolidinone, m.p. 224.degree.-225.degree. C.

EXAMPLE 36

5-[(3,4-dichlorophenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 37

4-[(2-thioxo-4-thiazolidinone)methylene]benzoic acid, m.p. .about.320.degree. C.

EXAMPLE 38

5-[(3,4-diethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 39

5-[(1H-indol-3-yl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 40

5-[(3-hydroxy-4-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 218.degree.-220.degree. C.

EXAMPLE 41

5-[(3-methoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 175.degree.-176.degree. C.

EXAMPLE 42

5-[(1,1'-biphenyl ]-4-yl)methylene ]-2-thioxo-4-thiazolidinone, m.p. 245.degree.-250.degree. C.

EXAMPLE 43

5-[(3-hydroxy-4-nitrophenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. .about.224.degree. C.

EXAMPLE 44

5-[(3-hydroxyphenyl)methylmethylene]-2-thioxo-4-thiazolidinone

EXAMPLE 45

5-[(3-methoxy-4-pentoxyphenyl)methylene ]-2-thioxo-4-thiazolidinone, m.p. 170.degree.-171.degree. C.

EXAMPLE 46

5-[(3-hydroxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. >225.degree. C.

EXAMPLE 47

5-[(4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 158.5.degree.-160.degree. C.

EXAMPLE 48

5-[(3-methoxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 207.degree.-207.5.degree. C.

EXAMPLE 49

5-[(3-ethoxy-4-propoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 156.degree.-157.degree. C.

EXAMPLE 50

5-[(3-propoxy-4-ethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 186.5.degree.-188.degree. C.

EXAMPLE 51

5-[(3,4-dipropoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 167.5.degree.-168.5.degree. C.

EXAMPLE 52

5-[(3-methoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, sodium salt m.p. >225.degree. C.

EXAMPLE 53

5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxy-phenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid, m.p. .about.265.degree. C.

EXAMPLE 54

5-[(3-methoxy-4-butoxyphenyl)methyl]-2-thioxo-4-thiazolidinone, m.p. 152.degree.-153.5.degree. C.

EXAMPLE 55

5-[(3,5-dichloro-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. >260.degree. C.

EXAMPLE 56

5-[(3-ethoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 57

5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone sodium salt, m.p. .about.254.degree. C.

EXAMPLE 58

5-[(3-ethoxy)-4-methoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. >225.degree. C.

EXAMPLE 59

5-[[3,5-bis(1-methylpropyl)-4-hydroxyphenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid, m.p. 191.degree.-193.degree. C.

EXAMPLE 60

5-[(3,4-dimethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 61

5-[(4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 180.degree. C.

EXAMPLE 62

5-[(3,5-dimethyl-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 260.degree. C.

EXAMPLE 63

5-[(3,5-dimethoxy-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 230.degree. C.

EXAMPLE 64

5-[(3-methoxy-4-pentoxyphenyl)methyl]-2-thioxo-4-thiazolidinone, m.p. 163.degree.-164.degree. C.

EXAMPLE 65

5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-3-methyl-4-thiazolidinone, m.p. 117.degree.-118.degree. C.

EXAMPLE 66

5-[(3-methoxy-4-pentoxyphenyl)methylene]-4-thiazolidinone, m.p. 174.degree.-175.degree. C.

EXAMPLE 67

5-[(3-methoxy-4-pentoxyphenyl)methyl]-4-thiazolidinone, m.p. 108.degree.-109.degree. C.

EXAMPLE 68

5-[(3-methoxy-4-hexoxyphenyl)methylene]-2-thioxo-4-thiazolidinone

EXAMPLE 69

5-[(3-methoxy-4-octoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 125.degree.-127.degree. C.

EXAMPLE 70

5-[(3,5-dimethoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone, m.p. 166.degree.-167.degree. C.

EXAMPLE 71

5-[[3-(1,1-dimethylethyl)-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-2-thioxo-4-thiazolidinone, m.p. 181.degree.-184.degree. C.

EXAMPLE 72

5-[[3-ethoxy-4-hydroxy-5-(methylthio-phenyl)phenyl]methylene]-2-thioxo-4-thiazolidinone, m.p. 190.degree.-192.degree. C.

EXAMPLE 73

5-[[3-ethoxy-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-2-thioxo-3-methyl-4-thiazolidinone, m.p. 137.degree. C.

EXAMPLE 74

5-[[3-ethoxy-4-hydroxy-5-(methylthiophenyl)phenyl]methylene]-4-oxo-2-thioxo-3-thiazolidine acetic acid m.p. 202.degree.-206.degree. C.

The present invention provides a method for lowering blood glucose levels in mammals comprising administering a therapeutically effective amount of a compound of formula I. The term "therapeutically effective amount", as defined herein, means the amount of compound necessary to provide a hypoglycemic effect following administration, preferably to a human susceptible to adult onset diabetes.

The hypoglycemic activity of the compounds of the present invention was determined by testing the efficacy of the compounds in vivo in male viable yellow obese-diabetic mice. The test procedure is described in detail below.

Test formulations were prepared by dissolving the test compound in a saline solution containing 2% Emulphor (a polyoxyethylated vegetable oil surfactant from GAF Corp.) to provide the dose level desired. Each test formulation was administered to six viable yellow obese-diabetic mice intraperitoneally at the beginning of the experiment. Blood glucose levels Were determined immediately before the first dose and at 2 and 4 hours thereafter using glucose oxidase. A mean was taken of the 6 values obtained before the first dose and at the 2 and 4 hour intervals. The 2 and 4 hour mean values, calculated as a percentage of the first dose mean value, are reported in Table 1, below. In Table 1, Column 1 provides the example number of the test compound, Column 2 provides the dose level of compound tested, and Columns 3 and 4 provide a measurement of the test animal's blood glucose level 2 and 4 hours after test compound administration, respectively, as a percentage of the test animal's pre-administration blood glucose level.

TABLE 1______________________________________HYPOGLYCEMIC ACTIVITY OF TEST COMPOUNDS INOBESE DIABETIC MICE Percent of InitialExample # of Blood Glucose LevelCompound Dose After AfterTested (mg/kg) 2 hrs. 4 hrs.______________________________________ 1 50 82 .+-. 5 75 .+-. 2 2 50 96 .+-. 1 82 .+-. 3 3 50 90 .+-. 10 73 .+-. 3 4 50 91 .+-. 4 72 .+-. 7 5 50 79 .+-. 4 71 .+-. 3 6 50 85 .+-. 6 72 .+-. 4 6 50 92 .+-. 4 79 .+-. 4 7 50 80 .+-. 4 91 .+-. 7 8 50 94 .+-. 4 84 .+-. 6 9 50 91 .+-. 8 83 .+-. 610 50 89 .+-. 4 80 .+-. 411 50 84 .+-. 3 85 .+-. 612 50 90 .+-. 7 69 .+-. 613 50 94 .+-. 4 88 .+-. 514 50 84 .+-. 7 71 .+-. 815 50 73 .+-. 5 62 .+-. 416 50 94 .+-. 8 96 .+-. 917 50 88 .+-. 8 89 .+-. 1018 50 89 .+-. 4 88 .+-. 519 50 85 .+-. 14 75 .+-. 420 50 76 .+-. 3 70 .+-. 521 50 99 .+-. 4 81 .+-. 622 50 77 .+-. 5 67 .+-. 222 50 77 .+-. 6 69 .+-. 623 50 74 .+-. 6 90 .+-. 624 50 78 .+-. 4 80 .+-. 525 50 78 .+-. 4 74 .+-. 425 25 84 .+-. 5 87 .+-. 626 50 80 .+-. 4 75 .+-. 227 50 93 .+-. 3 84 .+-. 628 50 83 .+-. 9 79 .+-. 729 50 84 .+-. 5 77 .+-. 630 50 78 .+-. 7 81 .+-. 531 50 76 .+-. 7 76 .+-. 532 50 75 .+-. 4 80 .+-. 832 50 80 .+-. 18 66 .+-. 1133 50 91 .+-. 6 86 .+-. 734 50 85 .+-. 8 79 .+-. 935 50 83 .+-. 5 85 .+-. 636 50 81 .+-. 7 90 .+-. 837 50 89 .+-. 4 80 .+-. 438 50 60 .+-. 5 59 .+-. 438 50 96 .+-. 6 80 .+-. 338 50 86 .+-. 4 81 .+-. 538 25 69 .+-. 9 65 .+-. 738 10 72 .+-. 4 71 .+-. 638 10 73 .+-. 8 59 .+-. 739 50 83 .+-. 4 76 .+-. 440 50 78 .+-. 5 72 .+-. 441 50 61 .+-. 3 51 .+-. 441 50 64 .+-. 6 54 .+-. 541 50 77 .+-. 5 62 .+-. 541 50 77 .+-. 5 72 .+-. 841 25 58 .+-. 6 45 .+-. 541 25 72 .+-. 7 64 .+-. 441 25 74 .+-. 7 70 .+-. 841 25 87 .+-. 5 85 .+-. 641 10 80 .+-. 7 59 .+-. 441 10 97 .+-. 7 75 .+-. 541 10 92 .+-. 7 92 .+-. 741 5 93 .+-. 10 71 .+-. 441 5 95 .+-. 4 97 .+-. 542 50 87 .+-. 8 70 .+-. 843 50 92 .+-. 7 88 .+-. 444 50 98 .+-. 4 88 .+-. 545 50 76 .+-. 7 57 .+-. 345 50 68 .+-. 2 66 .+-. 445 25 93 .+-. 4 87 .+-. 545 25 83 .+-. 10 78 .+-. 1246 50 79 .+-. 4 77 .+-. 547 50 99 .+-. 14 76 .+-. 848 50 70 .+-. 3 65 .+-. 348 25 87 .+-. 4 81 .+-. 549 50 83 .+-. 5 77 .+-. 750 50 75 .+-. 5 69 .+-. 551 50 89 .+-. 7 85 .+-. 852 50 73 .+-. 3 61 .+-. 453 100 83 .+-. 9 80 .+-. 1453 50 73 .+-. 4 55 .+-. 554 50 76 .+-. 7 74 .+-. 655 50 81 .+-. 3 75 .+-. 356 50 78 .+-. 4 72 .+-. 356 25 81 .+-. 8 75 .+-. 356 10 94 .+-. 4 97 .+-. 457 50 63 .+-. 6 58 .+-. 757 50 69 .+-. 5 63 .+-. 757 25 67 .+-. 7 66 .+-. 757 25 79 .+-. 10 70 .+-. 457 10 95 .+-. 3 87 .+-. 657 5 82 .+-. 6 68 .+-. 558 50 67 .+-. 2 75 .+-. 559 50 62 .+-. 5 59 .+-. 960 50 85 .+-. 4 78 .+-. 360 50 102 .+-. 6 81 .+-. 560 25 87 .+-. 7 89 .+-. 661 50 76 .+-. 5 61 .+-. 561 50 98 .+-. 8 79 .+-. 4______________________________________

The hypoglycemic activity of the compounds of the present invention was confirmed in a second in vivo test system; namely, the normal fed rat system. The procedure used in this test system is described below.

Male Sprague Dawley rats (Charles River Laboratories) weighing 175.degree.-200 g were used in this test system. Test formulations were prepared by suspending the test compound in 5% acacia (concentration of the drug was adjusted such that 0.25 ml/100 g body weight administered orally gave the desired dose on a body weight basis). The desired dose level of each test formulation was administered to four rats by oral garage at the beginning of the experiment. Blood glucose levels were determined immediately before the first dose and at 3 and 5 hours thereafter by an enzymatic procedure employing glucose oxidase and peroxidase coupled with a chromogenic oxygen acceptor. A mean was taken of the 4 values obtained before the first dose and at the 3 and 5 hour intervals. The 3 and 5 hour mean values, calculated as a percentage of the first dose mean value, are reported in Table 2, below. In Table 2, Column 1 provides the example number of the test compound, Column 2 provides the dose level of compound tested, and Columns 3 and 4 provide a measurement of the test animal's blood glucose level 3 and 5 hours after test compound administration, respectively, as a percentage of the test animal's pre-administration blood glucose level.

TABLE 2______________________________________HYPOGLYCEMIC ACTIVITY OF TEST COMPOUNDS INNORMAL FED RATS Percent of InitialExample # of Blood Glucose LevelCompound Dose After AfterTested (mg/kg) 3 hrs. 5 hrs.______________________________________15 167 84 8716 200 92 7917 200 78 6822 200 84 6824 200 100 10025 200 100 10026 200 100 10031 200 95 9232 200 100 9638 200 90 7441 160 76 6745 167 61 6347 200 82 7348 167 87 8149 200 100 9856 150 79 6557 200 84 7358 200 100 10061 200 89 8262 200 78 5363 200 69 5264 200 91 8965 200 100 9166 200 100 8667 200 92 8868 200 88 8969 200 93 88______________________________________

The hypoglycemic activity of the compounds of the present invention was confirmed in yet a third in vivo test system; namely, the obese diabetic Zucker rat (Zucker Diabetic Fatty Rat) test system. The rats used in this test system were 6 to 8 months old, weighed between 550 to 625 grams and had a pre-drug blood glucose level between 250 to 350 mg/dl. The procedure used in this test system is the same as that described for the normal fed rat test system, above. The results of such tests are set forth in Table 3, below. The format of Table 3 is the same as that used in Table 2.

TABLE 3______________________________________HYPOGLYCEMIC ACTIVITY OF TEST COMPOUNDS INOBESE DIABETIC ZUCKER RATS Percent of InitialExample # of Blood Glucose LevelCompound Dose After AfterTested (mg/kg) 3 hrs. 5 hrs.______________________________________22 50 53 5645 167 30 2047 167 74 6656 50 79 66______________________________________

Finally, the long-term hypoglycemic activity of the compounds of the present invention was tested in yet another in vivo test system. This long-term test system entailed incorporating test compound into the test animal's diet at various concentrations (control animal's diet contained no test compound). Such diet was then fed to the test or control animals for either 14 or 21 days. Each test or control animal was then bled from the tail (200-400 .mu.l sample of blood) at 0 (before diet started), 7, 14 and, if appropriate, 21 and 28 days after diet administration was started. Plasma samples were then obtained from each blood sample collected and the glucose concentration of such plasma samples was determined enzymatically.

The results of the long-termhypoglycemic test system described above are set forth in Table 4, below. In Table 4, Column 1 describes the type of rodents used in the test system, Column 2 provides the example number of the test compound or indicates that the numbers reported are for a control animal, Column 3 provides the concentration, in percent, of test compound in the test or control animal's diet. Columns 4-8 provide the plasma glucose concentration at days 0, 7, 14 and, if appropriate, 21 and 28, respectively, for the animals tested. Glucose lowering was not associated with depressed diet consumption.

TABLE 4______________________________________LONG-TERM HYPOGLYCEMIC ACTIVITY OFTEST COMPOUNDS Concen- Example tration No. of Test Plasma Glucose ConcentrationType of of Cmpd. Cmpd. in (mg/dl)Rodent* Tested Diet (%) 0 7 14 21 28______________________________________ZDF 45 0.1 388 140 155 -- --ZDF control -- 416 364 445 -- --ZDF 45 0.1 464 215 238 285 --ZDF 45 0.025 467 451 452 517 --ZDF control -- 478 499 571 565 --ZDF 45 0.1 357 171 166 -- --ZDF 64 0.1 339 187 182 -- --ZDF control -- 343 423 454 -- --ZDF 45 0.1 309 137 142 -- --ZDF 71 0.1 311 237 232 -- --ZDF 70 0.1 300 190 195 -- --ZDF control -- 317 286 255 -- --Male A.sup.vy /a 45 0.1 438 338 315 287 295(Harlan)Male A.sup.vy /a 38 0.1 340 351 328 303 331(Harlan)Male A.sup.vy /a control -- 429 414 410 390 359(Harlan)______________________________________ *ZDF = 8 week old male Zucker Diabetic Fatty rat; A.sup.vy /.sup.a = viable yellow mouse

The compounds of the present invention and the compounds utilized in the method of the present invention are effective over a wide dosage range. For example, dosages per day will normally fall within the range of about 0.5 to about 500 mg/kg of body weight. In the treatment of adult humans, the range of about 1.0 to about 100 mg/kg, in single or divided doses, is preferred. However, it will be understood that the amount of the compound actually administered will be determined by a physician in light of the relevant circumstances including the condition to be treated, the choice of compound to be administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms and the chosen route of administration. Therefore, the above dosage ranges are not intended to limit the scope of the invention in any way. While the present compounds are preferably administered orally, the compounds may also be administered by a variety of other routes such as the transdermal, subcutaneous, intranasal, intramuscular and intravenous routes.

While it is possible to administer a compound of the invention directly, the compounds are preferably employed in the form of a pharmaceutical formulation comprising a pharmaceutically acceptable carrier, diluent or excipient and a compound of the invention. Such formulations will contain from about 0.01 percent to about 90 percent of a compound of the invention.

In making the formulations of the present invention, the active ingredient will usually be mixed with at least one carrier, or diluted by at least one carrier, or enclosed within a carrier which may be in the form of a capsule, sachet, paper or other container. When the carrier serves as a diluent, it may be a solid, semi-solid or liquid material which acts as a vehicle, excipient or medium for the active ingredient. Thus, the formulations can be in the form of tablets, granules, pills, powders, lozenges, sachets, cachets, elixirs, emulsions, solutions, syrups, suspensions, aerosols (as a solid or in a liquid medium) and soft and hard gelatin capsules.

Examples of suitable carriers, diluents and excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, liquid paraffin, calcium silicate, microcrystalline cellulose, polyvinyl pyrrolidone, cellulose, tragacanth, gelatin, syrup, methyl cellulose, methyl- and propyl-hydroxybenzoates, vegetable oils, such as olive oil, injectable organic esters such as ethyl oleate, talc, magnesium stearate, water and mineral oil. The formulations may also include wetting agents, lubricating, emulsifying and suspending agents, preserving agents, sweetening agents, perfuming agents, stabilizing agents or flavoring agents. The formulations of the invention may be formulated so as to provide quick,.sustained or delayed release of the active ingredient after administration to the patient by employing procedures well-known in the art.

For oral administration, a compound of this invention ideally can be admixed with carriers and diluents and molded into tablets or enclosed in gelatin capsules.

The compositions are preferably formulated in a unit dosage form, each dosage containing from about 1 to about 500 mg, more usually about 5 to about 300 mg, of the active ingredient. The term "unit dosage form" refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of. active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical carrier, diluent or excipient therefor.

In order to more fully illustrate the operation of this invention, the following examples of formulations are provided. The examples are illustrative only and are not intended to limit the scope of the invention. The formulations may employ as active compounds any of the compounds of the present invention.

______________________________________FORMULATION 1Hard gelatin capsules are prepared using thefollowing ingredients: Amt. per Concentration by Capsule Weight (percent)______________________________________Compound of Example No. 5 250 mg 55.0Starch dried 220 mg 43.0Magnesium stearate 10 mg 2.0 460 mg 100.0______________________________________

The above ingredients are mixed and filled into hard gelatin capsules in 460 mg quantities.

______________________________________FORMULATION 2Capsules each containing 20 mg of medicament aremade as follows: Amt. per Concentration by Capsule Weight (percent)______________________________________Compound of Example No. 1 20 mg 10.0Starch 89 mg 44.5Microcrystalline 89 mg 44.5celluloseMagnesium stearate 2 mg 1.0 200 mg 100.0______________________________________

The active ingredient, cellulose, starch and magnesium stearate are blended, passed through a No. 45 mesh U.S. sieve and filled into a hard gelatin capsule.

______________________________________FORMULATION 3Capsules each containing 100 mg of activeingredient are made as follows: Amt. per Concentration by Capsule Weight (percent)______________________________________Compound of Example No. 45 100 mg 29.0Polyoxyethylenesorbitan 50 mcg 0.02monooleateStarch powder 250 mg 71.0 250.05 mg 100.02______________________________________

The above ingredients are thoroughly mixed and placed in an empty gelatin capsule.

______________________________________FORMULATION 4Tablets each containing 10 mg of activeingredient are made up as follows: Amt. per Concentration by Capsule Weight (percent)______________________________________Compound of Example No. 3 10 mg 10.0Starch 45 mg 45.0Microcrystalline 35 mg 35.0cellulosePolyvinyl 4 mg 4.0pyrrolidone (as 10%solution in water)Sodium carboxyethyl 4.5 mg 4.5starchMagnesium stearate 0.5 mg 0.5Talc 1 mg 1.0 100 mg 100.0______________________________________

The active ingredient, starch and cellulose are passed through a No. 45 mesh U.S. sieve and mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant powders which are then passed through a No. 14 mesh U.S. sieve. The granule so produced is dried at 50.degree.-60.degree. C. and passed through a No. 18 mesh U.S. sieve. The sodium carboxymethyl starch, magnesium stearate and talc, previously passed through a No. 60 mesh U.S. sieve, are then added to the granule which, after mixing, is compressed on a tablet machine to yield a tablet weighing 100 mg.

______________________________________FORMULATION 5A tablet formula may be prepared using theingredients below: Amt. per Concentration by Capsule Weight (percent)______________________________________Compound of Example No. 2 250 mg 38.0Cellulose 400 mg 60.0microcrystallineSilicon dioxide 10 mg 1.5fumedStearic acid 5 mg 0.5 665 mg 100.0______________________________________

The components are blended and compressed to form tablets each weighing 665 mg.

______________________________________FORMULATION 6Suspensions each containing 5 mg of medicamentper 40 ml dose are made as follows: Per 5 ml of suspension______________________________________Compound of Example No. 59 5 mgSodium carboxymethyl 50 mgcelluloseSyrup 1.25 mlBenzoic acid solution 0.10 mlFlavor q.v.Color q.v.Water q.s. to 5 ml______________________________________

The medicament is passed through a No. 45 mesh U.S. sieve and mixed with the sodium carboxymethylcellulose and syrup to form a smooth paste. The benzoic acid solution, flavor and color is diluted with some of the water and added, with stirring. Sufficient water is then added to produce the required volume.

______________________________________FORMULATION 7An aerosol solution is prepared containing thefollowing components: Concentration by Weight (%)______________________________________Compound of Example No. 53 0.25Ethanol 29.75Propellant 22 70.00(Chlorodifluoromethane) 100.00______________________________________

The active compound is mixed with ethanol and the mixture added to a portion of the propellant 22, cooled to -30.degree. C. and transferred to a filling device. The required amount is then fed to a stainless steel container and diluted further with the remaining amount of propellant. The valve units are then fitted to the container.

Claims

1. A method of reducing blood glucose concentrations in mammals which comprises administering a therapeutically effective amount of a compound of the formula ##STR27## wherein: Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.1 -C.sub.4 alkylphenyl, phenyl, NO.sub.2, F, Cl, hydroxy, phenoxy, C.sub.1 -C.sub.4 alkyloxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7).sub.2 or --N(R.sup.7)SO.sub.2 R.sup.7, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 1- or 2-naphthyl, (iv) 2- or 3-benzofuranyl, (v) 2- or 3-benzothiophenyl, (vi) 2- or 3-thienyl, (vii) 2-, 3- or 4-pyridyl, (viii) 2- or 3-furanyl, (ix) 1,3-benzodioxanyl, (x) substituted 1,3-benzodioxanyl, (xi) quinolinyl, (xii) 2- or 3-indolyl or (xiii) N-substituted 2- or 3-indolyl;

R.sup.1 is C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkylphenyl, hydrogen, phenyl or phenyl substituted with one or two substituents independently selected from Cl, Br, F, I, C.sub.1 -C.sub.4 alkyl C.sub.1 -C.sub.4 alkoxy, hydroxy, trifluoromethyl, --NH.sub.2, --NH(C.sub.1 -C.sub.4 alkyl), --N(C.sub.1 -C.sub.4 alkyl).sub.2 or C.sub.1 -C.sub.4 alkylthio;

R.sup.2 and R.sup.3 are each hydrogen or when taken together form a bond;

R.sup.4 and R.sup.5 are each hydrogen or when taken together are .dbd.S, or when one of R.sup.4 and R.sup.5 is hydrogen, the other is --SCH.sub.3 ;

R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, --SO.sub.2 CH.sub.3, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is cyano, --OR.sup.8, ##STR28## tetrazolyl, --NR.sup.10 R.sup.11, --SH, C.sub.1 -C.sub.4 alkylthio, or ##STR29## where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl, or ##STR30## alkyl; R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl, or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, C.sub.1 -C.sub.4 alkylphenyl, --(CH.sub.2).sub.q OH, --(CH.sub.2).sub.q N(C.sub.1 -C.sub.4 alkyl).sub.2, or --(CH.sub.2).sub.q S(C.sub.1 -C.sub.4 alkyl), where q is an integral from 1 to 6, both inclusive, or R.sup.10 and R.sup.11, taken together with the nitrogen atom to which they are attached form a morpholinyl, piperidinyl, piperazinyl, or N-methylpiperazinyl ring;

m is 0, 1, or 2;

with the provisos that

Ar cannot be phenyl substituted solely with one chloro substituent at the 4-position of the phenyl ring;

Ar cannot be phenyl substituted with a COOH moiety at the 2-position of the phenyl ring;

when Ar is phenyl substituted with two ethoxy moieties at the 3- and 4-positions of the phenyl ring, R.sup.1 must be hydrogen;

Ar cannot be phenyl substituted solely with two hydroxy substituents; and

when R.sup.4 and R.sup.5 are each hydrogen, R.sup.6 cannot be C.sub.1 -C.sub.6 alkyl,

or a pharmaceutically acceptable salt thereof, to a mammal in need of having its blood glucose concentration reduced.

2. A method of claim 1 which employs a compound wherein m is 0.

3. A method of claim 2 which employs a compound wherein R.sup.4 and R.sup.5 taken together are .dbd.S.

4. A method of claim 3 which employs a compound wherein R.sup.1 is hydrogen.

5. A method of claim 4 which employs a compound wherein R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, or --(CH.sub.2).sub.p --Y where p is 0, 1, 2, or 3 and Y is --OR.sup.8, ##STR31## --NR.sup.10 R.sup.11, or C.sub.1 -C.sub.4 alkylthio, where R.sup.8 is hydrogen, C.sub.1 -C.sub.4 alkyl or ##STR32## alkyl, R.sup.9 is hydrogen, C.sub.1 -C.sub.4 alkyl, or NH.sub.2 ; and R.sup.10 and R.sup.11 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, phenyl, or C.sub.1 -C.sub.4 alkylphenyl.

6. A method of claim 5 which employs a compound wherein R.sup.6 is hydrogen, C.sub.1 -C.sub.6 alkyl, or C.sub.2 -C.sub.6 alkenyl.

7. A method of claim 6 which employs a compound wherein Ar is (i) phenyl, (ii) phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, C.sub.1 -C.sub.8 alkylthio, trifluoromethyl, C.sub.1 -C.sub.4 alkylphenyl, phenyl, NO.sub.2, F, Cl, hydroxy, phenoxy, C.sub.1 -C.sub.4 alkyloxyphenyl, thiophenyl, C.sub.1 -C.sub.4 alkylthiophenyl, --COOR.sup.7, --N(R.sup.7)SO.sub.2 R.sup.7 or --N(R.sup.7).sub.2, where each R.sup.7 is independently hydrogen or C.sub.1 -C.sub.6 alkyl, (iii) 2-, 3- or 4-pyridyl, or (iv) 2- or 3-furanyl.

8. A method of claim 7 which employs a compound wherein Ar is phenyl substituted with from one to three substituents independently selected from C.sub.1 -C.sub.8 alkyl, C.sub.1 -C.sub.8 alkoxy, or hydroxy.

9. A method of claim 8 wherein the compound employed is 5-[(3,4-diethoxyphenyl)methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

10. A method of claim 8 wherein the compound employed is 5-[(3-methoxy-4-butoxyphenyl)methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

11. A method of claim 8 wherein the compound employed is 5-[(3-methoxy-4-pentoxyphenyl)methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

12. A method of claim 8 wherein the compound employed is 5-[(3-methoxy-4-pentoxyphenyl)methyl]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

13. A method of claim 8 wherein the compound employed is 5-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

14. A method of claim 8 wherein the compound employed is 5-[(3,5-dimethyl-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.

15. A method of claim 8 wherein the compound employed is 5-[(3,5-dimethoxy-4-hydroxyphenyl)methylene]-2-thioxo-4-thiazolidinone or a pharmaceutically acceptable salt thereof.