Dihydroatisine diacetate

Veatchine acetate (210) was hydrolyzed to veatchine (1) in methanol at room temperature without using any external base (152). This unusual hydrolysis was explained by participation of methoxide ion which was formed by opening of the oxazolidine ring by methanol. Diterpenoid alkaloid derivatives lacking the oxazolidine ring, such as dihydroatisine diacetate (211) and veatchine azomethine acetate (10), failed to give compounds 212 and 78, respectively, in methanol under these conditions. 

A full report on the C n.m.r. studies of these and related compounds and a rebuttal of some of the previously published n.m.r. spectral interpretations (cf. this Report, 1978, Vol. 8, p. 238) have appeared. The rebuttal was submitted prior to the publication of the X-ray crystallographic studies. n.m.r. spectral data were reported for atisine (1), atisinone (68), isoatisine (66), isoatisinone (69), dihydroatisine (65), dihydroatisine diacetate (70), atidine (71), atidine diacetate (72), atisine azomethine (73), atisine azomethine acetate (74), atisine dihydro-azomethine (75), atisine A-methyl dihydro-azomethine (76), veatchine [(67a) and (67b)], garryine (77), dihydroveatchine (78), dihydroveatchine diacetate (79), veatchine azomethine (80), veatchine azomethine acetate (81), veatchine dihydro-azomethine (82), and veatchine X-methyl dihydro-azomethine (83). 

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