The structure of crotonitenone, a novel casbane diterpene from Croton nitens Sw. (Euphorbiaceae)

Abstract

A novel casbane diterpene, crotonitenone {(E)-(1R*,5S*,7R*,11S*,14S*)-5-hydroxy-3,7,11,15,15-pentamethylbicyclo[12.1.0]pentadec-2-ene-4,8-dione}(7), C₂₀H₃₂O₃, has been isolated from Croton nitens(Euphorbiaceae) and its structure and relative stereochemistry have been established by chemical, spectral, and X-ray crystallographic means. Crystals of (7) are monoclinic, space group P2₁, with a= 12.446(1), b= 13.285(1), c= 5.872(1)Å, β= 97.02(1)°, and Z= 2. The structure was refined by least squares to R 0.040 and R′ 0.038.