Diterpenoids from euphorbia pithyusa subsp. cupanii
The aerial parts of Euphorbia pithyusa subsp. cupanii collected in Sardinia afforded eleven novel diterpenoids belonging to the lathyrane (1a), premyrsinane (4a-g), and tigliane (5a-c) types. Compounds 4a-g and 5a are esters of two new parent alcohols, named premyrsinol and 4,12,20-trideoxyphorbol, respectively. Structures were elucidated by spectroscopic and chemical methods. Puzzling differences between the NMR data of lathyrol (1c) and its esters were rationalized in terms of flipping of the exomethylene around the mean plane of the macrocycle.
Appendino
G
Dipartimento di Scienza e Tecnologia del Farmaco, Universita di Torino, Via Giuria 9, 10125 Torino, Italy, Dipartimento di Scienze Botaniche, Universita di Cagliari, Viale San Ignazio 13, 09123 Cagliari, Italy, and Analyticon AG, Hermannswe.
Belloro
E
Tron
GC
Jakupovic
J
Ballero
M