Identification of a precursor of beta-methyl-gamma-octalactone in the woodof Sessile oak (Quercus petraea (Matt.) Liebl.)

The 6'-O-gallate derivative of (3S,4S)-4-beta-D-glucopyranosyloxy-3-methylo ctanoic acid was isolated for the first time from the wood of Sessile oak ( Quercus petraea (Matt.) Liebl.) and shown to be a precursor of cis-beta-met hyl-gamma-octalactone. The structure of this precursor was determined by HR FAB-MS, NMR, LCMS, and chiral analysis of the Liberated (3S,4S)-beta-methyl -gamma-octalactone on a chiral fused silica capillary column. Optical rotat ion was shown to be identical to that of the same compound previously isola ted from the wood of Platycarya strobilacea Sieb. et Zucc. by Tanaka and Ko uno in 1996. Moreover, the 6'-O-gallate derivative of a threo-4-beta-D-gluc opyranosyloxy-3-methyloctanoic acid was tentatively identified as a minor p recursor of trans-beta-methyl-gamma-octalactone in the same wood of Sessile oak.