REACTION OF SCHIFF BASES WITH THIOGLYCOLIC ACID: SYNTHESIS OF THIAZEPIN-1(2H)-ONE AND THIAZOLIDIN-4-ONE COMPOUNDS

Reaction of Schiff bases with thioglycolic acid was set up with Dean stark apparatus in toluene. The Schiff bases containing aniline derivatives 1a and 2a gave thiazolidin-4-one containing compounds 1b and 2b only; 1-naphthyl amine gave a mixture of thiazolidin-4-one (3b) and thiazepin-1(2H)-one (3b’) containing compounds; 2-naphthyl amine (4a) gave and thiazepin-1(2H)-one containing compound 4b. The yields of reaction were moderate to high. The structures of these compounds were elucidated by 1H and 13C NMR and mass spectral analysis. Biological test results showed that Schiff base 4a was not active on any bacteria. Thiazolidine-4-one compound 1b was not active on bacteria and fungi, but was active against KB with IC50 21.33 (mg/mL). Thiazepine compound 4b exhibited activity on Staphyloccccus aureus bacterium at IC50 64.00 (mg/mL) and cancer cell line KB at IC50 11.52 (mg/mL).