Some isoindolo-fused heterocyclic systems by cyclodehydration of N-arylalkyl-3-hydroxyphthalimidines

Abstract

α-Hydroxy lactams formed by reduction or Grignard addition to appropriately N-substituted phthalimides (1a–d) undergo acid-catalysed cyclodehydration to derivatives of the isoindolo-fused heterocyclic systems (6)–(10). Ring closures to the naphthalene 2- or 8-position are observed to occur with N-1-naphthylalkyl substituents, the latter proved by an X-ray crystal structure determination of 13b-phenyl-7H-benz[de]isoindolo[1,2-a]isoquinolin-9(13H)-one (9b).