Sulfamic acid as energy efficient catalyst for synthesis of flurophores, 1-H-spiro [isoindoline-1,2′-quinazoline]-3,4′(3′H)-diones

An energy efficient synthesis of 1- H -spiro[isoindoline-1,2 ′ -quinazoline]-3,4 ′ (3 ′ H )-diones has been expediently accomplished by a reaction of isatin(s) / cyclic ketone and anthranilamide in ethanol at ambient temprature. Excellent yields of the products in short time duration, operational simplicity, and simple work-up procedure are the attractive features of the present protocol. Synthesized 1- H -spiro[isoindoline-1,2 ′ -quinazoline]-3,4 ′ (3 ′ H )-diones were found to be fluorescent with absorption in UV region (302, 362 nm) and emission in visible region (413-436 nm) with Stokes shift of 44-72 nm. Graphical Abstract Synthesis of 1- H -spiro [isoindoline-1,2’-quinazoline]-3,4’(3’H)-diones