Pachysandra alkaloids

The conversions shown in Scheme 18 interrelate a number of alkaloids and in conjunction with optical circular dichroism evidence establish the structure of spiropachysine (359), a major alkaloid in the leaves of Pachysandra terminalis Sieb. et Zucc. (Buxaceae), unique in possessing a five-membered spirolactam system.189 Spiropachysine (359) was reduced by lithium aluminium hydride to the deoxo-compound (360), whose dimethiodide on Hofmann degradation yielded two materials, the more strongly basic being a mixture of two olefins (361) which both afforded on hydrogenation the compound (362). The last compound was also prepared from... 

A histochemical investigation also established the presence of alkaloids in Pachysandra, Sarcococca, and Simmondsia (190). The alkaloids found in Sarcococca and Pachysandra are simple pregnane derivatives lacking the alkyl substitution at C-4 and C-14. The alkaloids isolated from Sarcococca pruniformis Lindley show close similarity in structure to alkaloids typical of pregnane-type alkaloids of Apocynaceae some of them were found in both families. 

Though the same is true of Pachysandra alkaloids, many of them are distinguished by the presence of a hydroxyl group in position 4 and/or by the amidic character of one of the nitrogen functions, particularly in position 3. 

The Pachysandra alkaloids have been intensively studied in Japan by Kikuchi and Uyeo. 

No investigation dealing with the biogenesis of Pachysandra or Sar-cococca alkaloids has been reported. However, their close similarity to Holarrhena alkaloids permits the assumption of analogous biosynthetic pathways. It may be noted that important questions concerning the biogenesis of steroidal Apocynaceae and Buxaceae bases remain still open. 

The full paper concerning the structural study of spiropachysine, a major alkaloid of the leaves of Pachysandra terminalis Sieb. and Zucc. (124), has been published. ... 

It should be added that epipachysamine-A, alkaloid of Pachysandra termin-is identical with synthetic 3/5-dimethylamino-20a-methylacetamido-5a-pregnane. 

The origin of the steroidal alkaloids of the Apocynaceae and some of the Buxaceae (Sarcococca and Pachysandra) appears to be linked with the biogenesis in these plants of steroidal derivatives of pregnanes, pregnenolone in particular. The Buxus alkaloids appear to be derived from 4,4,14a-trimethyl-9j3,19-cyclo-5a-pregnanes. 

Pachysandra termimlis (Buxaceae) is a perennial plant that grows in the shade in various locations in Japan and other temperate zones. This plant contains about 0.7% alkaloids in the dried above-ground parts the main alkaloids are pachysandrine A and pachystermine A [2]. These compounds possess the pregnane skeleton, which has a C2 imit remaining at the C-17 position, with two nitrogen atoms incorporated at the C2 side-chain and at C-3. 

Papilamine, papilicine, harappamine, and moenjodaramine were isolated from the leaves of Buxus papillosa (Buxaceae). These alkaloids retain the dimethyl moiety at the C-4 position and the methyl group at C-14, as in triterpenes [3]. These alkaloids possess an expanded seven-membered B ring, and the nitrogen atoms are attached similarly to the Pachysandra alkaloids. Alkaloids derived from Buxaceae are sometimes known as Buxus alkaloids [4]. 

At least 450 steroid and triterpenoid alkaloids have been reported (Verpoorte et al., 1991). Most steroidal alkaloids occur in a relatively small number of genera (Cestrum, Cy-phomandra, Lycopersicon, Nicotiana, and Solanum) of the family Solanaceae and of the family Liliaceae (Fritillaria, Veratrum, and Zygadems). Related alkaloids are known from the Apocynaceae (Funtumia, Holarrhena, and Ma-louetia) and Buxaceae. Alkaloids based on triterpenoid structures are much less common. Probably the best known ones are found in plants of the Buxaceae (especially Buxus, Pachysandra, and Sarcococca) (Gross et al., 1985 Roddick, 1980, 1986). 

Kikuchi, T., and S. Uyeo Pachysandra Alkaloids VIII. Structures of Pachystermine-A and -B, Novel Type Alkaloids Having a p-Lactam Ring. Chem. Pharm. Bull. 15, 549 (1967). 

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