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This alkaloid is obtained from the fruit, leaves and roots of Aiangium iamarckii Thw., the best source being the unripe fruit. Alangiside is laevorotatory with a specific rotation of [α]_D²⁶ - 105° (c 1.0, MeOH). It gives an ultraviolet spectrum in neutral MeOH with absorption maxima at 237 and 285 nm and exhibits a bathochromic shift in alkali to 247 and 303 nm. The base is a white amorphous powder decomposing at the melting point. The O-methyl derivative forms colourless needles when recrystallized from AcOH, m.p. 236°C. Acetylation with Ac20 in pyridine furnishes the pentaacetate which, on reduction with Adam's catalyst, gives the dihydroalangiside pentaacetate having a specific rotation of [α]_D²⁶ -120° (c 1. 0, MeOH). Cleavage of the base with ~-glucosidase yields D-glucose and the aglycone C19H21N04'

Kapil et ai., Chem. Commun., 904 (1971) Shoeb et ai., 1. Chem. Soc., Perkin I, 1245 (1975)