Aliphatic beta-D-glucosides from fruits of Carica pubescens

Ethyl 3-O-beta-D-glucopyranosylbutanoate, butyl 3-O-beta-D-glucopyranosylbutanoate and 3-oxo-octyl 1-O-beta-D-glucopyranoside were isolated from Carica pubescens fruit pulp by liquid chromatography on XAD Identifications were performed after peracetylation by comparison of HRGC and HRGC-mass spectral data with those of synthesized reference compounds. Chiral evaluation of glycosidically-bound 3-hydroxybutanoates and octane-1,3-diol was achieved by multidimensional gas chromatography, combining a polar achiral column (DB-Wax) with a chiral main column (heptakis-2,6-di-O-methyl-3-O-pentyl-beta-cyclodextrin/OV 1701 and 2,3- di-O-acetyl-6-O-tert-butyl-dimethylsilyl-beta-cyclodextrin/OV 1701, respectively). Comparison of retention times of synthesized, optically-enriched reference compounds with enzymically-released aglycones revealed enantiomeric excesses of the (S)-3-hydroxybutanoates; i.e. 96 % and 24 % for the ethyl and the butyl ester, respectively. Octane-1,3-diol exhibited an enantiomeric excess of (R)-90%. (C) 1997 Elsevier Science Ltd. All rights reserved.