Green protocol for conjugate addition of amines to p-quinones accelerated by water

Amines undergo smooth conjugate addition to p-quinones in H2O at ambient temperature in the absence of a catalyst to produce 2-aminoquinones in excellent yields. Significant rate acceleration of this reaction is observed in H2O compared to organic solvents. H2O played a dual role in simultaneously activating the p-quinone and amine. This new methodology constitutes an easy, highly efficient, and green synthesis of substituted p-quinones

Bismuth (III)-catalyzed rapid synthesis of 2,3-disubstituted quinoxalines in water

A variety of 2,3-disubstituted quinoxalines are readily prepared in high yields under extremely mild conditions by cyclocondensation of arene-1,2-diamines with 1,2-dicarbonyls using a catalytic amount of bismuth(III) triflate. The reactions of 2,3-di-aminopyridine with 1,2-dicarbonyls produce pyrido[2,3-b]pyrazine derivatives under similar conditions