Cevans

Many of the alkaloids from Veratrum, Zygadenus and related genera are based on the cevane structure 1. The chemistry of the Veratrum alkaloids has been reviewed from time to time both in this treatise (1-3) and elsewhere (4-6). The most recent of these articles was published in 1973, and many new compounds have been discovered since then. Recent years have seen the announcement of many X-ray crystal structure determinations on these stereochemically complex alkaloids. A total synthesis has been reported for only one of the natural products, namely, verticine (7). The work that lead to this notable achievement has been reviewed (8). The pharmacology of both the alkaloids (9-12) and their synthetic derivatives (13) has been reviewed, although not since 1977. This chapter takes a different approach from previous reviews. The chemical reactions used for structure determination and modification are first summarized, but the main part of the chapter is a series of tables which include all the known cevane derivatives, both old and new. This is intended as a reference source for future workers in the field. The literature has been covered to the end of Volume 113 of Chemical Abstracts (1990). 

Chapter 4. The Cevane Group of Veratrum Alkaloids John V. Greenhill and Paul Grayshan... 

Cevadine, Cevane see Veratrum steroid alkaloids. Ceveratrum alkaloida see Veratrum steroid alkaloids. Chaconine see Solanum steroid alkaloid glycosides. Chaenomeloidin see salicyl alcohol. 

Compounds with the 18,22,26-nitrilo-14(13- 12)-abeo-5 a-cholestane ring system 5a-cevane type, e. g., veracevine, see flgure 2), and rinally... 

A simpler group of compounds with the cevane skeleton occurs in the genus Fritillaria (Liliaceae). Medicinally, the most important alkaloids of Veratrum are the polyesters of protoverine (87) that have hypotensive properties. 

Thus, the C2 7-steroid alkaloids with C-nor-D-homo ring system, that is, with a jervane or cevane skeleton, with 18-nor-17j8-methylcholestane skeleton (23-27) or other alterations of the C27-carbon skeleton of cholestane, found in Liliaceae but not yet in Solanaceae, are not included. They are described exhaustively in other volumes of this series by Kupuchan and By (28) as well as by Tomko and Voticky (29). On the other hand, some Veratrum bases, for instance, teinemine and baikeine, belong to the 5o/amim-type alkaloids and are mentioned in this chapter. 

J. Tomko and Z. Voticky in Chapter 1 of Volume 14 (1973). Most recendy, the cevane subgroup of the veratrum alkaloids has been covered by John V. Greenhill and Paul Grayshan in Chapter 4 of Volume 41 (1992). Chapter 4 of the present volume compiles newly isolated alkaloids of the solanum and veratrum groups, their chemistry including recent total syntheses, and their biological properties. 

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