Synthesis of some benzimidazole‐ and benzothiazole‐derived ligand systems and their precursory diacids

Abstract

Procedures are described for the preparation of various bidentate and linear tetradentate benzimidazoles and benzothiazoles incorporating units such as pyridyl and thioether, and for the preparation of certain thioether dicarboxylic acids precursory to them. Condensations of ortho‐functinal anilines with carboxylic acids were carried out in polyphosphoric acid or refluxing HCl solution. Syntheses are reported for: [HO2C(CH2)2S(CH2)2]2X (X = O, S), 1,9‐bis(benzimidazol‐2‐yl)‐2,5,8‐trithianonane, 1,11‐bis(N‐methylbenzimidazol‐2‐yl)‐3,6,9‐trithiaundecane, 1,11‐bis(2‐benzimidazol‐2‐yl)‐6‐oxo‐3,9‐dithiaundecane, 2‐(2‐pyridyl)benzothiazole, 2,6‐bis(benzothiazol‐2‐yl)pyridine, 2‐(2‐pyridyl)‐N‐methylbenzimidazole, 2‐(2‐pyridylmethyl)benzimidazole and 2‐(N‐methyl‐2‐piperidyl)benzimidazole. The compounds were characterized, where appropriate, by their mass, uv and 1H‐nmr spectra. Copyright © 1983 Journal of Heterocyclic Chemistry