Conventional- and microwave-induced synthesis of biologically active 1,4-dihydropyridine derivatives containing benzothiazolyl moiety

Abstract

A series of N-(6-methoxybenzothiazolyl)-2,3,5,6-tetrasubstituted-4-(aryl)-1,4-dihydropyridines was synthesized by reaction of 2-amino-6-methoxybenzothiazole, aromatic aldehyde and active methylene compound in methanol by conventional as well as microwave irradiation (solvent free and solid support) methods. The microwave irradiation technique gives better yield and the reaction is complete in a very short period of time. Under microwave irradiation better yields are obtained in acidic alumina as compared to silica, neutral alumina, and basic alumina. All compounds were tested for antibacterial and antifungal activities and the results were compared with standard drugs. Entomological activities were also tested. The results showed that a change in substitution pattern in the 1,4-dihydropyridine derivatives causes marked effects on their antimicrobial activity.