BACKGROUND: BENZIMIDAZOLE DERIVATIVES EXHIBIT SIGNIFICANT ACTIVITY AGAINST SEVERAL VIRUSES SUCH AS HIV [1], HERPES (HSV-1) [2], RNA [3], INFLUENZA [4], AND HUMAN CYTOMEGALOVIRUS (HCMV) [1]. THE WIDESPREAD INTEREST IN BENZIMIDAZOLE-CONTAINING STRUCTURES HAS PROMOTED EXTENSIVE STUDIES FOR THEIR SYNTHESIS. WHILE MANY STRATEGIES ARE AVAILABLE FOR BENZIMIDAZOLE SYNTHESIS, THERE ARE TWO GENERAL METHODS FOR THE SYNTHESIS OF 2-SUBSTITUTED BENZIMIDAZOLES. ONE IS THE COUPLING OF PHENYLENEDIAMINES AND CARBOXYLIC ACIDS OR THEIR DERIVATIVES (NITRILES, IMIDATES, OR ORTHOESTERS), WHICH OFTEN REQUIRES STRONG ACIDIC CONDITIONS, AND SOMETIMES COMBINES WITH VERY HIGH TEMPERATURES OR MICROWAVE IRRADIATION. THE OTHER WAY INVOLVES A TWO-STEP PROCEDURE THAT INCLUDES THE OXIDATIVE CYCLO-DEHYDROGENATION OF SCHIFF BASES, WHICH ARE OFTEN GENERATED FROM THE CONDENSATION OF PHENYLENEDIAMINES AND ALDEHYDES.METHODS: ALDEHYDE AND O-PHENYLENEDIAMINE WERE THOROUGHLY MIXED IN ETHANOL, THEN TETRABUTYLAMMONIUM HYDROGEN SULFATE AS CATALYST WAS ADDED, AND THE SOLUTION HEATED AND STIRRED AT ROOM TEMPERETURE FOR APPROPRIATE TIME .ALSO ALDEHYDE AND O-PHENYLENEDIAMINE WERE THOROUGHLY MIXED, AND THEN TETRABUTYLAMMONIUM HYDROGEN SULFATE AS CATALYST WAS ADDED, AND THE MIXTURE IRRADIATED IN A MICROWAVE OVEN AT HIGH POWER LEVEL (MONITORED BY TLC).