Synthesis and in vitro studies of thiazolidine-4-carboxylic acid hydrazones as potential antitubercular agents

A series of forty six 2-substituted aryl-thiazolidine-4-carboxylic acid hydrazones (6a-c, 7a-c, 8a-c, 9a-c series) have been synthesized and isolated in their pure isomeric form (2R, 4R and 2S, 4R). Purity and structures have been ascertained by chromatographic and, IR, NMR and mass spectral data analysis. Antitubercular activity screening of these synthesized compounds against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant Mycobacterium tuberculosis (MDR-TB) has resulted in identification of three active compounds (6a 11, 6a 13, 6a 15) with MIC < 10 mu M against MTB and MDR-TB. The compound 6a 11 (2R, 4R isomer) shows the highest potency with MIC 1.33 mu M against MDR-TB. It is observed that the antitubercular activity of 2R isomer is four times more than the corresponding 2S isomer.