(-)-Tetrahydroalstonine 6474-90-4 Alstonine, 3,4,5,6-tetrahydro- Alstonine, 3,4,5,6-tetrahydro-, (3.alpha.)- Alstonine, tetrahydro- NSC72115 Oxayohimban-16-carboxylic acid, 16,17-didehydro-19-methyl-, methyl ester, (19.alpha.,20.alpha.)- TETRAHYDROALSTONINE