Jun Toda

Synthesis of Highly Deydrogenated Oxoerythrinan Alkaloids, Erytharbine and Crystamidine

2, 3-Dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) oxidation of 3, 8-dioxyoerythrinan-1(6)-enes in dioxane gave the ring B dehydrogenated products, the 1, 6-dienones, while oxidation in benzene gave the fully dehydrogenated products, the 1, 6, 10-trienones. The same trienones were obtained by DDQ oxidation of the 1, 6-dienones in bezene. On the contrary, oxidation of the isomeric enone, 3, 8-dioxoerythrinan-1-ene, in either dioxane or benzene gave the ring C dehydrogenated product, the 1, 10-dienone. The 1, 6, 10-trienones were transformed to the highly dehydrogenated 8-oxoerythrinan alkaloids, erytharbine and crystamidine, in racemic forms.