Reaction of enamino pyrrolidide and piperidide of 2,2-dimethyl-1,2,3,4-tetrahydrobenz[f]isoquinoline series with ninhydrin

Interaction of (4Z)-2,2-dimethyl-4-(2-oxo-2-pyrrolidin-1-ylethylidene)-1,2,3,4-tetrahydrobenz[f]isoquinoline with ninhydrin leads to annulation of an indeno[1,2-b]pyrrole ring. An analogous product is formed by replacing of the pyrrolidine ring with the piperidine ring. Further heating of the obtained glycol in the presence of AcOH leads to rearrangement with the formation of benz[f]isochromeno-[4',3':4,5]pyrrolo[2,1-a]isoquinoline hexacyclic system. © 2016, Springer New York LLC. All rights reserved.