CONFORMATIONAL ANALYSIS OF C3'-C8 CONNECTED BIFLAVONES

Two biflavones isolated from Taxus cuspidata were identified with ginkgetin (1) and sciadopitysin (2) which belong to C3′-C8 connected biflavones. The conformation of 2 in the solid state was determined by X-ray analysis and the conformations of 1 and 2 in the liquid state were discussed using nmr techniques. Complete assignments of 1H and 13C nmr spectra about 1 were made on the basis of COSY, HMQC, HMBC and nOe experiments.