Synthesis and structure-activity relationships of some 2,5-disubstituted benzoxazoles and benzimidazoles as antimicrobial agents

The synthesis of a new series of 2,5-disubstitutedbenzoxazoles 5a-e, and 2,5-disubstitutedbenzimidazoles 6a-h are described in order to determine their antimicrobial activities and feasible structure-activity relationships (SAR). The synthesized compounds were tested in vitro against 3 Gram-positive, 3 Gram-negative, bacteria and a fungus Candida albicans. 5c, and 5e were found most active than the others against Bacillus subtilis at a MIC value of 3.12 mu g/ml and the compounds 5e, 6a and 6e indicated significant antibacterial activity against the enterobacter Pseudomonas aeruginosae. 5a, 5c, 5d and 6d also exhibited antimycotic activity against C. albicans. The antibacterial and antimycotic activities of 5-6 are compared with several control drugs.