Veatchine azomethine

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. 

Recently, Pelletier, Nowacki, and Mody 155) reported that treatment of alkaloid imine derivatives with ethylene oxide in acetic acid or methanol afforded the oxazolidine ring-containing alkaloids in excellent yield. Treatment of lindheimerine (7) with ethylene oxide in acetic acid afforded ovatine (6) in 98% yield. Similarly, veatchine azomethine acetate (10) afforded veat-chine acetate (210) in 97% yield. Formation of the oxazolidine ring in these... 

Unlike ethylene oxide, oxetane reacted very slowly with the alkaloid imine derivatives to afford low yields of tetrahydro-l,3-oxazine derivatives. Treatment of veatchine azomethine acetate (10) with oxetane in acetic acid at 50° afforded the six-membered carbinolamine ether, homoveatchine acetate (220), in 25% yield. The latter was isolated as a mixture of C-20 epimers. 

Masamune 104) has also converted compound CCCXII, obtained from veatchine azomethine acetate, by a multistep procedure to the monoester carboxylic acid CCLIII. Since the latter has already been converted to atisine by Pelletier and Parthasarathy 96) this work completes in a formal sense the synthesis of atisine also. 

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). 

MW 299.2249 Atisine-/V,20-azomethine Azitine Cuauchichicine-N,20-azome thine Garryfoline-/V,20-azomethine Veatchine-N,20-azome thine C20H29NO... 

The atisine and Garrya (35,36) alkaloids have been interrelated by converting both atisine (XXX) and veatchine, by a parallel sequence of degradations, to the same A-acetyl ester (XCV) (35, 36). The respective azomethine acetates (LXXXVII, LXXXVIII) derived from atisine (12,16-bond) and veatchine (13,16-bond) were converted to the A-acetyl derivatives (LXXXIX, XC) by reduction, acetylation, and saponification. Oxidation of LXXXIX and CX with permanganate/periodate under controlled conditions gave the respective carboxylic acids (XCIa,... 

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