Studies in the chemistry of erythrina alkaloid derivatives—III : Two isomers of 2,3,4,4a,5,6,7,7a,8,9,10,11-dodecahydro-2,10-dioxo-1H-benzo[d]naphthalene

Diketone 2,3,4,4a,5,6,7,7a,8,9,10,11-dodecahydro-2,10-dioxo-1H-benzo[d]-naphthalene prepared by annulation of N-(1-cyclohexenyl)pyrrolidine with vinyl methyl ketone, was found to consist of two stereoisomers. Theoretical dipole moments of these were calculated, and their structures were shown by moment dipole measurements to be cis A/B, cis A/C and trans A/B, cis A/C, respectively. The isomer trans A/B, cis A/B was converted into trans A/B, cis A/C dodecahydro-1H-benzo[d]naphthalene by the Wolff-Kishner reduction.