Synthesis of methyl1 (E)-2' ,4'' -thiazachalcones and their N-alkyl derivatives, photochemistry with theoretical calculations and antimicrobial activities

A series of 9 new (E) -thiazachalcones (1-3), and their N -alkyl substituted derivatives (4-6), and stereoselective dimerization products (7-9) were synthesized, then tested for antimicrobial activity against all test microorganisms except Pseudomonas aeruginosa. The new compounds (1-6) without dimerization products (7-9) showed good antimicrobial property against Staphylococcus aureus, Listeria monocitogenes, and Enterococcus faecalis. The possible dimerization products of compounds (1-3) were calculated theoretically. Experimental and theoretical calculation showed that δ -truxinic type dimer is the most stable isomer.