Investigation of New Procedure for Selective Reaction and Synthesis of Some New 2-Substituted Benzimidazole Derivatives

The objective of this study is to investigate a new procedure for specifically reducing the NO2 group present on the aromatic ring along with ester group. We revealed that NaBH4-FeCl2 serves as a crucial reagent in this process. The reduction mediated by NaBH4-FeCl2 exhibited remarkable chemoselectivity, yielding the wanted products in outstanding yields of up to 90-95%. Furthermore, this process was successfully utilized in the synthesis of diamino compound, and in the synthesis of 2-substituted benzimidazole derivatives The diamine compounds was condensed with various aromatic or heterocyclic carboxylic acids in the existence of EDC.HCl and catalyst DMAP. The resulting moiety or product underwent cyclization by using CH3COOH at 100-110°C. Both the reactions (coupling & cyclization) reaction completed effectively, within the minimal reaction times. The structure of created compounds was confirmed using modern spectral techniques like FT-IR, mass spectrometry, NMR.