Synthesis of some imidazole‐ and pyrazole‐ derived chelating agents

Abstract Procedures involving condensation of o ‐phenylenediamines with carboxylic acids, and reaction of bifunctional alkyl halides with bifunctional nucleophiles are described. Syntheses are reported of 2,6‐bis‐(2‐benzimidazyl)‐pyridine, 1,3‐bis(2‐benzimidazyl)‐2‐thiapropane, 1,7‐bis(2‐benzimidazyl)‐2,6‐dithiaheptane, 2‐hydroxymethyl‐5,6‐dimethylbenzimidazole, 2‐chloromethyl‐5,6‐dimethylbenzimidazole hydrochloride, 1,7‐bis(5,6‐dimethyl‐2‐benzimidazyl)‐2,6‐dithiaheptane, 3,6‐bis(1‐pyrazolyl)pyridazine, 2‐(2‐hydroxy‐3‐methyl–phenyl)benzimidazole, 2‐(2‐hydroxyphenyl)benzimidazole, 5‐(2‐hydroxphenyl)‐3‐methyl‐1‐phenylpyrazole, 3(5)‐(2‐hydroxyphenyl)‐5(3)‐methylpyrazole, 3(5)‐(2‐hydroxyphenyl)‐5(3)‐phenylpyrazole, and 1,3‐bis((5‐methylpyridyl)imino)isoindoline.