Microwave Synthesis and Antibacterial Activities of Some Imidazolidine Derivatives Containing 1,3,4-Oxadiazole Moiety

Abstract

5-(4-Aminophenyl)-2-thiol-1,3,4-oxadiazole (1) was synthesized via the reaction of carbon disulfide with 4-aminobenzoyl hydrazide in presence of potassium hydroxide in absolute ethanol. Compound 1 was converted to the corresponding diazonium salt which was introduced in coupling reaction with alkaline solution of 2-hydroxybenzaldehyde as coupling reagent to give azooxadiazole derivative 2 containing aldehyde group. The resulting aldehyde 2 was then introduced in condensation reactions with the primary aromatic amines including (4-bromoaniline, 4-chloroaniline, 4-nitroaniline, 3-nitroaniline, 4-methoxyaniline and 4-hydroxyaniline) using microwave irradiation technique in absolute ethanol to produce six imine derivatives of 1,3,4-oxadiazole (3a-f), respectively. Treatment of the resulting imines 3a-f with glycine using microwave irradiation in tetrahydrofuran afforded six new imidazolidines 4a-f substituted with 1,3,4-oxadiazole moiety, respectively. in vitro Antibacterial activity of the target compounds were investigated using two types of bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The results indicated that the newly synthesized imidazolidines (compounds 4d and 4f) showed enhanced activity against Gram-negative bacteria when compared with that of the control drug (gentamycin).