Multistep microwave-assisted divergent synthesis of indolo-fused pyrazino-/diazepinoquinoxalinones on PEG support

Abstract

Synthesis of amino acid and indoline-substituted dinitrobenzene on a soluble polymer support (PEG) and its further reductive double-ring closure to afford structurally diverse indolo-fused pyrazino-/diazepinoquinoxalinones is described. Traceless synthesis of quinoxalinones coupled with application of the Pictet-Spengler-type condensation reaction furnished these novel scaffolds. These hitherto novel heterocycles are synthesized in shorter times under microwave irradiation conditions in comparison with that of classical reaction conditions.