Microwave Controlled Reductive Cyclization: A Selective Synthesis of Novel Benzimidazole-alkyloxypyrrolo[1,2-a]quinoxalinones

Abstract

An efficient cascade synthesis of novel benzimidazole linked alkyloxypyrrolo[1,2-a]quinoxalinones was explored on soluble polymer support under micro-Wave irradiation. Two exclusive protocols have been developed for the partial and reductive cyclization by Controlling the microwave energy, Commencing from the smile substrate, ortho nitro, pyrrol: carboxylates, N-hydroxy pyrroloquinoxalinones were obtained by,, partial reductive cyclization (60 degrees C, 7 min), and the synthesis of pyrroloquinoxalinones was accomplished by full reductive, cyclization (85 degrees C, 12 min). This method represents the first synthesis N-hydroxy pyrroloquinoxalinones using Pd/C and ammonium formate as reducing agents: Further employing a variety Of alkyl bromides, the obtained pyrroloquinoxalinones were transformed to their corresponding O-, and N-alkylated analogues to deliver the diversified, novel molecular entities.