Croton diasii

Leonurus cardiac (Labiatae) contains some diterpenoids which have been provisionally assigned clerodane structures such as (50). Diasin (51) is a c/5-labdane related to the clerodanes which has been isolated from Croton diasii (Euphorbiaceae). Its structure was determined by and C n.m.r. spectroscopy. A series of furanoid nor-diterpenoids has been isolated from Dioscorea bulbifera (Dioscoreaceae). The structures of the diosbulbins D, E, F, G, and H, (52)—(56), were determined" by a series of spectral and chemical studies and that of diosbulbin G (55) was confirmed" by an X-ray analysis. 

Alvarenga M A, Gottlieb H E, Gottlieb O R, Magalhaes M T, da Silva V O 1978 Diasin, a diterpene from Croton diasii. Phytochemistry 17 1773-1776... 

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