Hydrazinolysis of 2-phenyl-2-(phthalimidoalkyl)indan-1,3-diones

Abstract

Hydrazinolysis of 2-phenyl-2-(3-phthalimidopropyl)indan-1,3-dione gave 1,2,3,10b-tetrahydro-10b-hydroxy-1-phenylpyrido[2,1-a]isoindol-6(4H)-one (11)(major product), and 2,3,4,4a-tetrahydro-4a-phenylindeno[l,2-b]pyridin-5-one (14)(minor product). Hydrazinolysis of the butyl analogue gave 2,3,4,5-tetrahydro-5a-phenylindeno[l,2-b]azepin-6(5aH)-one (15)(major product) and 2,3,4,5-tetrahydro-1-phenylazepino[2,1 -a]isoindol-7-one (18)(minor product).

The pyrido[2,1-a]isoindol-6(4H)-one (11) and the azepino[2,1-a]isoindol-7-one (18) arise via ring expansion of the carbinolamines from the 2-(2-aminoalkyl)-2-phenylindan-1,3-diones to give 2,3,4,5-tetrahydro-7-hydroxy-6-phenylbenz[3,4]azonin-1 -one and 3,4,5,6-tetrahydro-8-hydroxy-7-phenyl-benz[3,4]azecin-1(2H)-one respectively which undergo transannular cyclisation