Isolation and characterization of major diterpenes from C. canephora roasted coffee oil

A simple laboratory procedure for the isolation of pure cafestol and 16-O-methylcafestol together with beta-sitosterol from coffee is disclosed. Cafestol and 16-O-methylcafestol have been exhaustively characterized through 1D and 2D H-1, C-13 NMR, CD and X-ray diffraction. For the first time, the molecular structure of cafestol is reported and the assignment of the absolute configuration is unequivocally given by exploiting anomalous scattering of a brominated derivative.