Direct synthesis of 17a-ethoxyimino-8-aza-D-homogonanes by annelation of 3,4-dihydroisoquinolines with 2-acetyl-5,5-dimethyl-3-ethoxyiminocyclohexanone

The annelation reaction of Schiff bases by β,β’-tricarbonyl compounds has been extended to 3-ethoxyimino derivatives of 2-acylcyclohexane-1,3-diones. The first direct synthesis of 8-aza-D-homogonanes with a modified carbonyl group at the pharmacologically significant C(17a) position has been carried out.