Study on the Alkaloids of Melodinus tenuicaudatus

Abstract

Fourteen alkaloids were isolated from the stem bark of Melodinus tenuicaudatus Tsiang et P. T. Li. Eleven of them were identified as known alkaloids, namely, scandine (2), Δ¹⁴-eburnamine (4), vindolinine N _b-oxide (5), 11-methoxytabersonine (6), vindolinine (7), epi-vindolinine N _b-oxide (8), hazuntine (9), compactinervine (10), 11-hydroxytabersonine (11), Δ₁₄-vincine (12), and normacusine B (14). Two alkaloids were new: 10-hydroxyscandine (1), and the dimer, tenuicausine (3); their structures were elucidated by spectroscopic and chemical methods. One alkaloid (13) occurring in trace amounts, could not be identified.