2,4-Disubstituted thiazoles, Part III. Synthesis and antitumor activity of ethyl 2-substituted-aminothiazole-4-carboxylate analogs

The synthesis of several new ethyl 2-substituted-aminothiazole-4-carboxylate analogs is described. The prepared compounds were tested for their in vitro antitumor activity against 60 human tumor cell lines by the National Cancer Institute (NCI) and showed potential anticancer activity. Ethyl 2-[3-(diethylamino)-propanamido]-thiazole-4-carboxylate (14) exhibited remarkable activity against RPMI-8226 leukemia cell line with GI50 value of 0.08 microM, and a broad spectrum activity against all the tumor cell lines used with GI50 (MG-MID) value of 38.3 microM. The detailed synthesis and antitumor screening data are reported.

Synthesis, antitumor and antitubercular evaluation of certain new xanthenone and acridinone analogs

6-Chloro-4-substituted methyl-4-xanthenones and 2,4-dichloro-1-substituted amino-9-(10 H)-acridinones were synthesized as tricyclic planar analogs and tested for their in vitro antitumor and antitubercular activity. The obtained derivatives were also evaluated for two biochemical, mechanism-based screens to explore their ability to inhibit the cell cycle control proteins cdc2 kinase and cdc25 phosphatase as molecular targets which may account for their antitumor activity. 4-(N1-Amidino)-sulphanilamidomethyl-6-chloro-9-xanthenone (10) proved to be the most active member of these derivatives exhibiting a broad spectrum antitumor potency against a wide range of human tumor cell lines with full panel median growth inhibition (GI50), total growth inhibition (TGI) and median lethal concentration (LC50) mean graph midpoint (MG-MID) values of 3.2, 12.7 and 21.8 mumol l-1, respectively. Meanwhile, compound 4-(N1-Acetyl)sulphanilamidomethyl-6-chloro-9-xanthenone (9) showed GI50, and TGI (MG-MID) values of 25.6 and 87.6 mumol l-1, respectively with a moderate selectivity for leukemia cell lines at the GI50 level. Compound 9 exhibited a weak in vivo growth inhibitory effect against many human tumor cells cultivated in hollow fibers and implanted into the intraperitoneal or subcutaneous physiologic compartments in mice. In addition, compounds 15, 20, 23-25 showed potential activity against mycobacterium strain H37Rv at 12.5 micrograms ml-1 concentration. The detailed synthess, spectroscopic and biological data are reported.

Synthesis and antitumor activity of some new substituted quinolin-4-one and 1,7-naphthyridin-4-one analogs

The synthesis of some new analogs of quinolin-4-one and 1,7-naphthyridin-4-one is described. The prepared compounds were tested for their in vitro antitumor and cdc2 kinase or cdc25 phosphatase inhibitory activity. Compound ethyl 7-oxo-2,3-dihydro-7H-pyrido [1,2,3-de][2,3-b]pyrido-1,4-thiazine-6-carboxylate (6b) showed antitumor activity against CNS SNB-75, breast T-47D, and lung NCI-H522 cancer cell lines with GI50 values of 8.3, 17.6, and 22.7 microM, respectively. Meanwhile, the compounds ethyl 4-oxo-8-phenylthio-1H,4H-quinoline-3-carboxylate (11a) and 4-oxo-8-phenylthio-1H,4H-1,7-naphthyridine-3-carboxylic acid (12b) have proved to be cdc25 phosphatase inhibitors at IC50 values of 11 and 5 microM, respectively.

Synthesis and biological evaluation of new cyclopenteno[b]thiophene derivatives as local anesthetic and antiarrhythmic agents

A series of ethyl 2-substituted amino-cyclopenteno[b]thiophen-3-carboxylates was synthesized as a carticaine analogues and evaluated for their local anesthetic and antiarrhythmic activity. Compounds ethyl 2-[1-oxo-2-(ethylamino)ethylamino]-(4a), ethyl 2-[1-oxo-2-(n-propylamino)-ethylamino]-(4c), ethyl 2-[1-oxo-2-(4-methylpiperazino)ethylamino]-(4e), ethyl 2-[1-oxo-2-(ethylamino)propylamino]-(5a) and ethyl 2-[1-oxo-2-(n-propylamino)propylamino]cyclopenteno[b]thiophen++ +-3-carboxylate (5c) proved to possess local anesthetic and antiarrhythmic activity comparable to carticaine and lidocaine. The active compounds exert their antiarrhythmic potency via blocking Na+ channels as in case of 5c or blocking Ca+2 channels as in case of 4a, 4c and 5c. Compound 4e exhibited a dual mechanism by blocking both Na+ and Ca+2 channels.

Synthesis and antitumor activity of 9-anilino, phenylhydrazino, and sulphonamido analogs of 2- or 4-methoxy-6-nitroacridines

Synthesis of several new 9-anilino, phenylhydrazino, and sulphonamido analogs of 2- or 4-methoxy-6-nitroacridine derivatives is described. The prepared compounds were tested for their in vitro antitumor activity against 60 human tumor cell lines by the National Cancer Institute (NCI) and showed a potential anticancer activity. Compounds 9-(phenylhydrazino)-2-methoxy-6-nitroacridine (8a) and 9-(4-chlorophenylhydrazino)-4-methoxy-6-nitroacridine (9b) exhibited a broad spectrum antitumor activity with full panel (MG-MID) median growth inhibition (GI50), of 16.1 and 10.9 microM and total growth inhibition (TGI) of 66.7 and 37.9 microM, respectively. Meanwhile, compounds 15a and 15b showed moderate selectivity toward leukemia cell lines. As a trial to explore the mode of action of their antitumor activity, the 6-nitroacridine analogs were evaluated for their inhibitory effect on major cell cycle control proteins cdc2 kinase and cdc25 phosphatase as possible molecular targets that may account for antimitotic potency. None of the tested compounds proved to exert their activity via this antimitotic mode of action.

Synthesis of certain 5-substituted 2-thiohydantoin derivatives as potential cytotoxic and antiviral agents

A convenient route is reported for the synthesis of certain series of 2-thiohydantoins carrying various heterocyclic substituents such as 5-bromothienylidene 3a,b, 5-(2-carboxyphenylthio)-2-thienylidene 4a,b and 4H-thieno[2,3-b][1]benzothiopyran-4-one 5a,b. Glycosylation of these thiohydantoins afforded the S-glycosyl derivatives 10a-d. The synthesized compounds were tested for their activity against HIV-1 virus and as antitumor agents.

Synthesis and cardiotonic activity of certain imidazo[2,1-b]-1,3,4-thiadiazole derivatives

A series of 5-imino-2-methyl-4-(4'-substituted phenacyl)-1,3, 4-thiadiazole derivatives 3-5 have been synthesized and further used to prepare a series of 2-methyl-6-(4'-substituted phenyl)imidazo[2, 1-b]-1,3,4-thiadiazoles 6-8 and 5-substituted-2-methyl-6-(4'-substituted phenyl) imidazo[2, 1-b]-1,3, 4-thiadiazoles 9-18. All of newly prepared imidazothiadiazole compounds were screened for their cardiotonic activity in isolated guinea pig atria. The detailed synthesis, spectroscopic and biological data are reported.

5-substituted-2-thiohydantoin analogs as a novel class of antitumor agents

Certain series of 2-thiohydantoin derivatives, carrying various substituents at position 5 such as 5-bromo-2-thienylmethylene, 5-(2-carboxyphenylthio)-2-thienylmethylene and 2-methylene-4H-thieno[2,3-b][1]benzothiopyran-4-one, were evaluated for their antitumor activity. Compound 5-(5-bromo-2-thienylmethylene)-3-morpholinomethyl-2-(2,3,4,6 -tetra-O-acetyl -beta-D-glucopyranosylthio)hydantoin proved to possess a broad spectrum antitumor activity against a wide range of different human cell lines of nine tumor subpanels causing both cytostatic and cytotoxic effects, resulting in full panel median growth inhibition (GI50) and total growth inhibition (TGI), with a median lethal concentration (LC50) at 15.1, 41.7 and 83.2 microM, respectively. On the other hand, compound 5-(5-bromo-2-thienylmethylene)-2-thiohydantoin and compound 5-(5-bromo-2-thienylmethylene)-3-phenyl-2- (2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl-thio)hydantoin showed potential selectivity against leukemia cell lines. Further derivatization of these compounds, deduced from the obtained tentative structure-activity relationships, may lead to more potent agents.

Novel diarylsulphide derivatives as potential cytotoxic agents

A series of diarylsulphides bearing amino, acetamido, sulphonamido, benzamido or arylideneamino synthons have been synthesized and evaluated for their antimicrobial and cytotoxic activities. Some of the tested compounds proved to possess a remarkable activity. The detailed synthesis, spectroscopic and biological data are reported.

Synthesis and biological testing of certain 2-(5-substituted-2-thienylthio)benzoic acid derivatives

The syntesis of a number of 2-(5-substituted-2-thienylthio)benzoic acid derivatives is described. The synthesized compounds were screened for their muscle relaxant and parasympatholytic activities and the results are reported.