Reaction of 6-aminouracils with aldehydes in water as both solvent and reactant under FeCl3·6H2O catalysis: towards 5-alkyl/arylidenebarbituric acids

Abstract

5-Alkyl/arylidenebarbituric acids were efficiently synthesized through an FeCl₃·6H₂O catalyzed domino reaction of 6-aminouracils, water and aldehydes with water serving a dual role as both solvent and reactant, under benign reaction conditions. A study on comparative substrate scope of 6-aminouracil versus barbituric acid showed similar efficacy towards 5-alkyl/arylidenebarbituric acids. The protocol is the first detailed report to prepare regioselectively 5-alkyl/arylidenebarbituric acids starting from 6-aminouracils, which is an alternative and competing strategy to hitherto all known reactions directly employing barbituric acids.