Low melting oxalic acid dihydrate: proline mixture as dual solvent/catalyst for synthesis of spiro[indoline-3,9′-xanthene]trione and dibarbiturate derivatives

Abstract

A simple, proficient and an elegant synthetic route for the synthesis of spiroxanthene and dibarbiturate derivatives has been developed under the umbrella of green chemistry. The operational simplicity, good to excellent product yields, easy workup procedures and non-chromatographic purification procedure are remarkable features of this protocol. Furthermore, the use of low transition temperature mixture as green reaction medium reduces burden on environment and makes the present method environmentally sustainable. The calculated values of green chemistry metrics are found to be in well agreement with ideal values signifying greenness of developed protocol.