Four new norlignan glycoside isomers from the twigs of Cephalotaxus oliveri Mast

Four novel isomers of norlignan glycoside were isolated from Cephalotaxus oliveri Mast.. Their structures were elucidated as 3S-4″-O-β- d -glucopyranosylnyasol 1, 3S-4′-O-β- d -glucopyranosylnyasol 2, 3S-4″-O-β- d -glucopyranosylhinokiresinol 3, 3S-4′-O-β- d -glucopyranosylhinokiresinol 4 by extensive spectroscopic methods including 1D and 2D NMR experiments (1H, 13C, DEPT, 1H–1H COSY, HSQC, HMBC, ROESY) along with HR-ESIMS and comparison to literature data. Their absolute configurations were elucidated through CD spectra coupled with the quantum chemical CD calculations.