The chemistry of Eremophila spp. XIX. New cembrane diterpenes from E. granitica and E. abietina

Abstract

The isolation and structural elucidation of five new cembrane diterpenes from two Eremophila species is reported.

(1R,3S,4S,7E,11Z)-3,15-Epoxy-19-oxocembra-7,11-dien-18-oic acid (3) and (1R,3S,4S,7Z,11Z)-3,15-epoxycembra-7,11-dien-18-oic acid (7) were isolated from E. granitica, and dimethyl(1R,3S,4S,7E,11Z)-3,15-epoxycembra-7,11-diene-18,19-dioate (16), (1R,3S,4S,8R,11Z)-3,15-epoxycembr-11-ene-18,19-dioic acid (14) and its dimethyl ester were isolated from E. abietina. Structural studies on the diol derived from (14) were carried out by single-crystal X-ray diffraction analysis.