RESUMO
A convenient green synthesis of benzopyrazines and bis-benzopyrazines has been performed by the condensation of diversely substituted diamines and dicarbonyl compounds in water using indium powder as catalyst under controlled microwave exposure. The effects of microwave power, and temperature on this reaction are investigated in detail to identify the best condition. A wide range of diversely substituted diamines and dicarbonyl compounds produce excellent yield of the corresponding benzopyrazines and bis-benzopyrazines. A comparative study has also been made between microwave-induced procedure and conventional method. The present method is atom-economical, environmentally friendly, and affords synthetically useful and challenging products very rapidly.