Abstract
From the stem bark of Alstonia angustifolia, eleven alkaloids were isolated. Seven of them are known ones: echitamine (1), N(b)-demethylechitamine (2), pseudoakuammigine (3), tubotaiwine (5), akuammicine (6), N(b)-β-methylantirhine (12), and N(b)-methylakuammidine (13). The four others, pseudoakuammigine N-oxide (4), akuammicine N-oxide (7), N(b)-demethylalstogustine (8), and N(b)-demethylalstogustine N-oxide (11), are new alkaloids. Their structures were determined by means of spectroscopic analysis
and chemical correlation with known alkaloids.
