Effective one pot synthesis of new biologically active pyrimido[1,2-a]benzimidazoles

The synthesis of newpyrimido[1,2-a]benzimidazoles (4a-j) is based on the Biginelli like cyclo condensation of aromatic aldehydes and acetoacetamide derivatives with 2-amino benzimidazole containing a guanidine fragment. The cyclo condensations were achieved by heating of the starting materials in dimethylformamide (DMF) as solvent. Synthesized compounds were characterized by analytical and spectral (IR, 1H NMR, mass spectral and elemental analyses) data and have been screened for their antimicrobial activity.