Twice annulations of 6, 7-dimethoxy-3, 4-dihydroisoquinoline hydrochloride (7) stereoselectively give the pseudoberbenone (12), the catalytic reduction of which preferentially affords the alloberbanone (15). On a series of reactions (oxidation, O-methylation, sodium borohydride reduction, ether cleavage and catalytic reduction) 12 is converted into the berbanone (25) via the berbadienone (21). Oxidations of 15 and 25 with mercuric acetate smoothly afford the 1, 11-didehydro compounds (17) and (26), respectively. Two isomeric metho salts (18) and (19) obtained from 17, and the one (31) from 21 are found to give the starting materials by demethylation under conditions of the Hofmann degradation. Stereostructures of the compounds obtained here are examined on the basis of the infrared and nuclear magnetic resonance spectra. Their formation pathways are also discussed.
Epoxidation of 1-(p-methoxybenzyl)-2-methyl-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (7) affords the two isomeric epoxides (14 and 15). Chemical evidence shows that performic acid exclusively attacks from the cis-side to the 1-substituent. The competitive reactions of 14 and 15 are qualitatively examined by gas chromatographic and thin-layer chromatographic analyses.
Abstract Durch Oxida‐ t tion des Hexahydro‐chinolizinons (II) werden das Tetrahydro‐Derivat (I) und das Dihydro‐Derivat (III) erhalten, deren Methylierung mit (V) in verschiedenen Lösungsmitteln untersucht wird.
