Transformations of kurchi alkaloids—I The action of nitrous acid on holarrhimine

Holarrhimine (I), 18-hydroxy-3β,20-diamino-5-pregnene, was treated with nitrous acid under different conditions. From the reaction mixtures several crystalline products were isolated and characterized as 3β-hydroxy-18-20β-oxido-5-pregnene (II), the nitrate ester of II (III), 3β-nitro-18-20β-oxido-5-pregnene (IV), 6-methoxy-18-20β-oxido-3,5-cyclopregnane (V) and 3β,18-dihydroxy-20-amino-5-pregnene (VII). On treatment with boron trifluoride and acetic anhydride compounds II, IV, V and an unidentified compound (VI) gave the same triacetate 3β,18,20-triacetoxy-5-pregnene (VIII).