Asian Journal of Research in Chemistry

2-Amino benzimidazole condensed with ethyl-2-cyano-3, 3-bis(methylthio)acrylate using catalytic amount of potassium carbonate and DMF as solvent to form 3-cyano-2-metylthio-4-oxo-4H-pyrimido [1, 2-a] benzimidazole (3). The formed compound (3) reacted with differently substituted aryl/heteryl hydrazino compounds then it gives series of substituted pyrazolo [4, 5-e]-4H-pyrimido [2, 3-b] [1, 3] benzimidazoles (5a-h). Structure of compounds were confirmed by spectroscopic techniques IR, mass, ¹H & ¹³C NMR and analytical properties. all synthesized compounds were screened for their antioxidant activity.