Synthesis of a new heterocyclic system — Fluoreno[1,2-d]imidazol-10-one

Abstract

Synthesis of various substituted fluoreno[1,2-d]imidazol-10-ones (5a–5g) has been accomplished by the cyclization of diazotized 1-substituted 4-benzoyl-5- aminobenzimidazoles (4a–4g). Compounds 4a–4g were prepared by reductive ring opening of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles (3a–3g) with zinc dust in EtOH/NaOH solution.