Cyclocondensation of o-Phenylenediamines with 2-Oxo-ethanimidothioates: A Novel Synthesis of 2-Amino-3-(het)aryl-quinoxalines

摘要

2-Amino-3-(het)aryl-quinoxalines were synthesized by the cyclization reaction between 2-oxo-ethanimidothioates and o-phenylenediamine in the presence of acid catalyst p-TSA in toluene at 80 degrees C. The products were obtained in 58-84 yields. The required substrates 2-oxo-ethanimidothioates were synthesized by the condensation reaction between alpha-oxodithioester and amine in the presence of sodium hydride in DMF followed treatment with methyl iodide.