Ecdysteroid, steroid alkaloids, steroidal

The absolute configuration at C-24 in some ecdysteroids has been established by C n.m.r.Assignments are reported also for some steroidal alkaloids, ° and for a series of twelve 5a-cardenolides. ... 

Steroids, which are a class of compounds that occur in nature and in synthetic products, have a cyclopen-tanoperhydrophenanthrene skeleton. The carbon atoms and rings are labeled according to the scheme shown in Fig. 1. The following classes of compounds belongs to steroids sterols, bile acids, cardenolides, androgens, estrogens, corticosteroids, steroid sa-pogenins, steroid alkaloids, ecdysteroids, and vitamin D. 

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