Abstract
Dehydrogenation of serpentinine in boiling p-cymene in the presence of 30% palladium-carbon, which has been kept in a desiccator for 1 week, gave the following three products: Compound D was shown to be identical with dihydroflavopereirine prepared synthetically. Compound E was proved to be the half-ester of Compound B. Compound F, which was also obtained by dehydrogenation of serpentinine at 100° over palladium-maleic acid, contained two chromophores of quaternary β-carboline and 6, 7-dihydroindolo[2, 3-α]quinolizinium and was inferred to have a double molecular structure (VI).
