The synthesis of 9,10-dimethyl-4,6,6a,7,8,9,10,10a-octahydroindolo[3,4-gh]isoquinoline, the 8,9-dimethyl-8-aza analogue of ergoline

Abstract

The title compound (15) has been synthesised by ring expansion of the cyclopentanone 4-acetyl-9-methyl-4,5,5a,6,6a,7,9,9a-octahydroindeno[6,5.4-cd]indol-8-one (5) by means of the Schmidt reaction. The stereochemistry at C-6a, -9, and -9a of the starting ketone and at C-6a, -10, and -10a of the four lactams produced by the reaction is established by means of the ¹H n.m.r. spectral analysis. Two of these isomeric lactams and the corresponding isomers of the title compound have been isolated and characterised.