6,7-Didehydro-22α-ethyl-15,16-dimethoxyobscurinervan-21-one

Also isolated from Aspidosperma obscurinervium Azembuja, this alkaloid may be separated from the preceding base by column chromatography. It has an almost identical structure, the methyl group being replaced by an ethyl group. It has [α] ²⁷ _D - 54° (c 0.95, CHC13).

Brown, Djerassi.,i. Amer. Chern. Soc., 86, 2451 (1964)