Synthesis of newer thiadiazolyl and thiazolidinonyl quinazolin-4 3H-ones as potential anticonvulsant agents.

A series of 3-[[5-(alkylbenzylideneamino)-1,3,4-thiadiazol-2-yl]methylamino-2]-methyl-6-monosubstitutedquinazolin-4(3H)-one (4a-4l) have been synthesized via condensation of 3-[(5-amino-1,3,4-thiadiazol-2-yl)methylamino]-2-methyl-6-monosubstitutedquinazolin-4(3H)-one (3a-3b) with various aromatic aldehydes. Cycloaddition of thioglycolic acid with 4a-4l yielded 3-([4-[2-(alkylphenyl)-4-oxo-1,3-thiazolidin-3-yl]-1,3,4-thiadiazol-2-yl]methylamino)-2-methyl-6-monosubstitutedquinazolin-4(3H)-one (5a-5l). The compounds were screened for their anticonvulsant activity and were compared with the standard drugs, phenytoin sodium, lamotrigine and sodium valproate. Out of the 30 compounds the most active compound was 3-([4-[2-(m-methoxy-p-hydroxyphenyl)-4-oxo-1,3-thiazolidin-3-yl]-1,3,4-thiadiazol-2-yl]methylamino)-2-methyl-6-bromo-quinazolin-4(3H)-one (5l).