Complete assignment of the 1H and 13C NMR spectra of the tetraisoprenylated benzophenone 15-epiclusianone.

Abstract

An NMR study of 15-epiclusianone, 1-benzoyl-6-hydroxy-14,14-dimethyl-3,5,15-tri(3-methyl-2-butenyl)- bicyclo[3.3.1]non-1-ene-4,6-dione (1), a novel tetraisoprenylated benzophenone isolated from pericarp of fruits of Rheedia gardneriana, is described. In addition to conventional 1D NMR techniques, 2D shiftcorrelated NMR experiments [1H 1H-COSY, 1H 13C-HMQC-1J(C,H), 1H 13C-HMBC-nJ(C,H) (n = 2 and 3) and 1H 1H-NOESY] were used for 1H and 13C chemical shift assignments of this natural product. The 1D 13C NMR spectrum of 1 in the solid state was also obtained.