1-Acetylcyclopentene → 1,2,3,3a,5,6,10b,11,12,12a-Decahydro-8,9-dimethoxybenzo[a]cyclopenta[f]quinolizin-12-one

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Reaction Steps

A mixture of 23.0 g (0.1 mole) of 6,7-dimethoxy-3,4-dihydroisoquinoline hydrochloride, 23.0 g (0.2 mole) of 1-cyclopenten-1-yl methyl ketone in 25 ml of ethanol is refluxed overnight then evaporated in vacuo. The residual oil is partitioned between water and ether after which the aqueous layer is separated and washed with ether, made basic with concentrated ammonium hydroxide solution and stirred. A sticky solid material forms which is washed with water, partially dried in vacuo, dissolved in methylene chloride, dried over sodium sulfate, filtered and evaporated. The residual material is dissolved in benzene and chromatographed on alumina eluting with benzene then with benzene-15% ethyl acetate. The solid obtained is recrystallized from benzene-hexane to give 1,2,3,3a,5,6,10b,11,12,12a-decahydro-8,9-dimethoxybenzo[a]cyclopenta[f]quinolizin-12-one, M.P. 105°-114° C.

Provenance & Evidence