Synthesis of novel drug-like small molecules library based on 1

Abstract

A series of novel ‘drug-like’ small molecules based on 1H-benzo[d]imidazole derivatives bearing furan-2-yl, 4-piperidine and 5-aryl/aminoaryl substitutions were designed and synthesised. The key intermediate tert-butyl-4-(5-bromo-2-(furan-2-yl)-1H-benzo[d]imidazol-1-yl)piperidine-1-carboxylate (5) was synthesised via sequential reaction starting from 4-bromo-1-fluoro-2-nitrobenzene (1). The 5-aryl-substituted molecular library was generated via Suzuki–Miyura coupling of tert-butyl-4-(5-bromo-2-(furan-2-yl)-1H-benzo[d]imidazol-1-yl)piperidine-1-carboxylate (5) with various boronic acids while Buchwald coupling of 5 with various anilines generated the second molecular library of tert-butyl-4-(2-(furan-2-yl)-5-(arylamino)-1H-benzo[d]imidazol-1-yl)piperidine-1-carboxylates. The structures of all the newly synthesised compounds were confirmed by spectral analysis. The optimised procedure gives easy access to two new molecular libraries of 1H-benzo[d]imidazoles with operational simplicity and good yield.