Synthesis and antimicrobial activity of some new 1-methyl [(N-alkyl phthalyl)-benzimidazolo]-3'-chloro-4'-substituted azetidin-2-ones

N-Alkyl phthalyl benzimidazoles (IV) were synthesized by treating o-phenylene diamine with N-phthalyl substituted amino acids (III). These were subjected to Mannich reaction using formaldehyde and ammonium chloride giving the Mannich base i.e. N-alkyl phthalyl-1-amino methyl benzimidazoles (V). Reaction of V with appropriate aromatic aldehydes under anhyd conditions yielded the Schiff's bases (VI). Cyclization of VI with chloroacetyl chloride in 1,4-dioxan in presence of triethyl amine gave 1-methyl [(N-alkyl phthalyl)-benzimidazolo]3'-chloro-4'-substituted azetidin-2-onesVII. The compounds were characterized by means of mass, IR, PMR and elemental analysis. Some of the azetidinones have shown promising antimicrobial activity.