l-Proline-catalysed sequential four-component “on water” protocol for the synthesis of structurally complex heterocyclic ortho-quinones†
Abstract
The L-proline-catalyzed synthesis of 7-(aryl)-8-methyl-10-phenyl-5H-benzo[h]pyrazolo-[3,4-b]quinoline-5,6(10H)-diones via the four-component sequential reaction of N bonds in a single operation. The environmental advantages of the method include short reaction time, excellent yield, easy work-up, and the absence of