One-Pot Synthesis of Dibenzo[b,e][1,4]diazepin-1-ones

A simple and efficient method for the synthesis of wide range of 3,3-dimethyl-11-alkyl or aryl 2,3,4,5-tetrahydro-1H-dibenzo[b,e][1,4]diazepin-1-ones, recently reported as hepatitis C virus (HCV) NS5B polymerase inhibitors, is presented. The proposed method consists of one-pot condensation between 1,2-phenylenediamine and 5,5-dimethylcyclohexane-1,3-dione (dimedone) followed by cyclization with various alkyl and aryl acyl chlorides catalyzed by Er(III) triflate. With respect to methods previously reported, the proposed one-pot procedure furnishes appreciably higher yield of product in shorter reaction time.