AMARYLLIDACEAE ALKALOIDS - TRANSFORMATION OF LYCORINE INTO HIPPEASTRINE

Dioxy-N-cyanodihydronorhippeastrine (IX), obtained by the von Braun reaction of dihydrolycorine (VII), has been converted into deoxydihydrohippeastrine (XIV). Degradation of diacetyllycorine (XVIIIb) with cyanogen bromide and subsequent treatment of the degradation products with 5% ethanolic potassium hydroxide afford a neutral (XIXa) and two basic products (XX and XXI), of which, XIXa and XX may be transformed via a secondary amine XXIIa into hippeastrine (XVII). The structure determination of XXI was based on the structure elucidation of its two hydrogenation products, XXIVa and XXVa. The stereochemical relationships between dihydrolycorine and dihydrohippeastrine (XVI), and also between lycorine (XVIIIa) and hippeastrine (XVII) have been accomplished. Thus the absolute configurations of dihydrohippeastrine and hippeastrine are unequivocally established. © 1968.