Kopsirachin, ein ungewöhnliches Alkaloid aus der Apocynaceae Kopsia dasyrachis Ridl. 189. Mitteilung über organische Naturstoffe

Abstract

Kopsirachine, an Unusual Alkaloid from the Apocynaceae Kopsia dasyrachis Ridl.From the leaves of Kopsia dasyrachis Ridl. a new type of alkaloid, kopsirachine (1), built up from catechin (2) and skytanthine (3) has been isolated. The structure elucidationis based on spectral and chemical evidence. Oxidative cleavage of its derivative 4 with KMnO4 afforded veratric acid wich was identified as its methylester by comparison with an authentic sample. Pyrolysis of 1 yielded δ‐skytanthine (3). The stereochemistry of the skytanthine substituents in 1 could not yet be established.