Synthesis and molecular modeling studies of 2-[2-(3-nitrophenyl)-1h-benzimidazol-1-yl]-acetamide derivatives as anthelmintic

Benzimidazole derivatives of substituted 2 [2-(3-nitrophenyl)-1H-benzimidazole-1-yl] acetamide analogues were synthesized and studied for antihelminthic activity. Compounds 3a-o were obtained in three steps, starting with the Oxidative Condensation of the appropriate 3-nitrobenzaldeyde, o-phenylenediamine and sodium hydrogen sulfite to form 2-(3-nitrophenyl)-1H-benzimidazole (1a). In second step Nucleophilic substitution, Chlorine atom of ethylchloroacetate will attach on nitrogen of benzimidazole by replacing hydrogen with elimination of hydrochloric acid to form ethyl [2-(3-nitrophenyl)-1H-benzimidazole-1-Yl acetate (2a).In third step amide formation from ester takes place by substitution of electrophilic with loss of ethanol to form substituted 2 [2-(3-nitrophenyl)-1H-benzimidazole-1-yl] acetamide 3a-o The antihelminthic activity showed that compounds 3f, 3h, 3i, 3j and 3k good activity against Indian earthworms (Pheretima posthuma) in comparison to albendazole.