Crystal and molecular structure of 1R,3S,5S,7R,10R-3,6,6,10,14-pentamethyltricyclo[10.3.0.05,7]pentadeca-11,14-diene-1,10-dihydroxy-2,13-dione (Japodagrol), C20H28O4

A new cytotoxic macrocyclic diterpenoid named Japodagrol, C20H28O4, has been isolated from the ornamental plantJatropha podagrica, family Euphorbiaceae, grown in Nigeria. The structure of the title compound, C20H28O4, was solved by X-ray analysis.M r =332.44, monoclinic space groupC2,a=23.285(4),b=6.5105(12),c=12.505(3) A,β=98.504(17),V=1874.8 A3,Z=4,D c =1.178 Mg/m3. CuKα radiation (graphite crystal monochromator, λ=1.54184 A),μ (CuKα)=6.13 cm−1,F(000)=720,T=290 K. Final conventionalR factor=0.035,R w =0.038 for 3349 “observed” reflections. The structure was solved with the programDirdif. The 5-membered ring is closed to a half-chair form. The compound contains inter- and intramolecular hydrogen bonds.