A general method for the synthesis of structurally diverse quinoxalines and pyrido-pyrazine derivatives using camphor sulfonic acid as an efficient organo-catalyst at room temperature
Gurpreet Kaur, R. Arvind Singh, Navdeep Kaur, Bubun Banerjee
Abstract
A mild, convenient, eco-friendly, general and practical approach has been developed for the synthesis of a series of structurally diverse quinoxaline derivatives via the condensation reactions of various 1,2-diaminobenzene derivatives and 1,2-dicarbonyls such as phenanthrene-9,10-dione, acenaphthylene-1,2-dione or benzil using a catalytic amount of camphor sulfonic acid as an efficient, commercially available, low cost, organo-catalyst in aqueous ethanol at room temperature. Under the same optimized conditions we were also able to synthesis dibenzo[f,h]pyrido[2,3-b]quinoxaline as well as 10-bromoacenaphtho[1,2-b]pyrido[2,3-e]pyrazine from the reactions of pyridine-2,3-diamines and phenanthrene-9,10-dione or acenaphthylene-1,2-dione respectively.