One-pot synthesis and antimicrobial activity of new 4,6-disubstituted-3,4-dihydropyrimidine-2(1H)-thiones

A series of 3,4-dihydropyrimidine-2(1 H )-thiones (3a-i) were synthesized in moderate yields via a one-pot reaction of 3-acetyl-2,5-diclorothiophene (1), aryl aldehydes (2a-i) and thiourea in methanolic solution of potassium hydroxide under reflux conditions. All newly synthesized compounds were characterized by extensive NMR analysis, including 1 D NMR experiments ( 1 H and 13 C) and 2D NMR experiments (COSY, HMBC and HSQC), as well as ESI-MS and HRESI-MS data. The antimicrobial activity of all new compounds (3a-f) was tested against bacteria and fungi. Thione derivative (3c) only showed activity against Staphylococcus aureus , Bacillus subtilis and Aspergillus niger .