Microwave Synthesis of 2,3-Disubstituted-5-methyl-1,3-imidazolidines-4-one Bearing Benzothiazole Moiety and Elementarily Assessment of Their Antibacterial Action

Abstract

Diazotization of 2-aminobenzothiazole 1 through using sulfuric acid and sodium nitrite resulted in the formation of diazonium salt which reacted with alkaline solution of salicylaldehyde to produce azo-aldehyde derivative of benzothiazole 2. The resulting aldehyde 2 was condensed with the primary aromatic amines involving (4-nitroaniline, 3-nitroaniline, 4-hydroxyaniline, 4-methoxyaniline, 2-methoxyaniline, 4-bromoaniline, 4-chloroaniline and 2,4- dichloroaniline) using microwave irradiation method in absolute ethanol to produce eight imines of benzothiazole 3a-h, respectively. The imine compounds 3a-h have been treated with L-alanine using microwave irradiation in tetrahydrofuran afforded eight new imidazolidines 4a-h containing benzothiazole moiety, respectively. Preliminary antibacterial activity of the target compounds was investigated in vitro using two kinds of bacteria, Escherichia coli (Gram-negative) and Staphylococcus aurous (Gram-positive). The results showed that the newly prepared imidazolidines (compounds 4c, 4d, 4f, 4g, and 4h) exhibited greater activities than gentamycin against Gram-positive bacteria. On the other hand, compounds 4c and 4f were also showed better activities against Gram-negative bacteria when compared with that of the control drug.