Novel 12-deoxy-16-hydroxyphorbol diesters isolated from the seed oil of Jatropha curcas

Six unstable intramolecular diterpene esters were isolated from the seed oil of Jatropha curcas. Five of these, Jatropha factors C-2-C-6 (3-7), are new natural products and the structure of the known Jatropha factor C-1 (2) has,been revised. All compounds possess the same diterpene moiety, namely, 12-deoxy-16-hydroxyphorbol (1). The dicarboxylic acid moieties of 2-5 contain a bicyclo[3.1.0]hexane unit, and those of 6 and 7 a cyclobutane unit, which is described for the first time within this compound class. Compounds 4 and 5 are C-8' epimers. The structures of 2-7 were elucidated by spectroscopic methods and give an insight into the biogenesis of the characterized substances.