Sulfamic acid-catalyzed, environmentally benign synthesis of bis-tetronic acids at ambient temperature

Abstract

An enviro-economic protocol has been described for the synthesis of bistetronic acids by pseudo-three-component condensation between aldehydes/isatins and tetronic acid using sulfamic acid as a solid acid catalyst. Easy commercial availability of the catalyst at extremely low cost, excellent yields and avoidance of conventional purification procedures are the main merits of this energy efficient protocol. Graphical AbstractO O O Sulfamic acid EtOH, RT