Diterpenoid alkaloid delphinine

Comparison of the I3C NMR spectrum of pyrodelphinine [552] and delphinine [553] shows the large high frequency shift of C(17) in [552] (S 78-6 in [552], d 63-3 in [553]) resulting from interaction between the nitrogen lone pair and the C(8)-C(15) double bond. (326) The 13C NMR spectra of a variety of other diterpenoid alkaloids (from aconitum... 

The chemistry of the diterpenoid alkaloids, rather than their structure elucidation by physical methods, has attracted more interest during the year covered by this Report. While several new alkaloids have been reported, most of the research on these polycyclic, polyfunctional bases has involved chemical conversions and synthetic methods. Most notably, Wiesner s group at New Brunswick, Canada, has reported a fourth-generation synthesis of the delphinine-type alkaloids. That this marvel of synthetic engineering accomplishes the stated goals1 of a highly efficient, fully regio- and stereo-specific synthesis of these complex natural products is abundantly clear. 

In 1959 Katsui and his co-workers (69, 70) isolated a diterpenoid alkaloid, designated initially as base D and later as isodelphinine, from the mother liquors accumulated during the isolation of miyaconitine and miy-aconitinone from the roots of A. miyabei Nakai, a plant native to Hokkaido, Japan. On the basis of chemical studies, they reported that base D contains an N-methyl, a benzoxyl, an acetoxyl, a hydroxyl, and four methoxyl groups. On treatment with acetyl chloride, base D gave a monoacetate, mp 188-190°. The data indicated that base D has the same empirical formula and functional groups as delphinine (31), but differs from delphinine by the mixture-melting point (mmp) and infrared spectra. On the basis of an infrared analysis and chemical studies, Katsui postulated that isodelphinine is a C-14 epimer of delphinine. 

Over the last ten years Professor Wiesner and his co-workers at the University of New Brunswick have made important contributions to the synthesis of delphinine (31) and related diterpenoid alkaloids (147-150). 

This paper described the chemotaxonomy characteristics of two C2o-diterpenoid alkaloids and five C 19-diterpenoid alkaloids from Delphinium albocoeruleum Maxim of Chinese origin. The study indicated that the compound delelatine may be considered as a chemotaxonomic marker for the Delphinium genus as it occurs in Delphinium elatum. Delphinium barbeyi, D. tatsinenense [66], and Delphinium giraldii [67], Delphinine, a major compound, may possibly be utihzed for identification of D. albocoeruleum Maxim. 

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