Antibacterial Activity of some New substitued 4‐(2‐Benzothiazolylamino‐2H[1]‐Pyran‐2‐ones

Some new substitued 4‐(2‐benzithiazolylamino‐2H[1]‐pyran‐2‐ones are synthesized by condensation of 2H[1}‐pyran‐2‐ones and corresponding 2‐aminobenzothiazoles. Condensation of 4‐chloro‐6‐methyl‐2H[1]‐pyran‐2‐one 2 and 2‐aminobenzothiazoles 3(a‐c) gave corresponding 4‐(2‐benzothiazolylamino)‐6‐methyl‐2H[1]‐pyran‐2‐ones 4(a‐c) . By condensation of 4‐chloro‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6a and 2‐aminobenzothiazoles 3(ad) were synthesized 4‐(2‐benzothiazolylamino)‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6a and 4‐(6‐ethoxy‐2‐benzothiazolylamino)‐3‐nitro‐6‐methyl‐2H[1]‐pyran‐2‐one 6c . The antibacterial activity of products 4(a‐d) against E. coli S. aureus and Clebsiella were investigated. Compounds 4(a‐d) showed light bactericide activity against E. coli , S. aureus and Clebsiella. Compounds 4b and 6d were more active against E. coli . Emphatic activity against S. aureus exhibited compounds 4c and 6d whereas compounds 6a and 6d exhibited the strongest activity against Clebsiella . In general there was a direct positive correlation between increasing concentration of the compound and antibacterial activity.