Preparation of L-Lyxo-Hexos-5-Ulose Through C-3 Epimerization of Bis-Glycopyranosides of L-Arabino-Hexos-5-Ulose1
作者:
PierLuigi Barili,
Giancarlo Berti,
Giorgio Catelani,
Felicia D'Andrea,
FrancescoDe Rensis,
Giampaolo Goracci,
期刊:
Journal of Carbohydrate Chemistry
(Taylor Available online 1998)
卷期:
Volume 17,
issue 8
页码: 1167-1180
ISSN:0732-8303
年代: 1998
DOI:10.1080/07328309808001891
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The unreported title compound and its 2,6-di-O-benzyl derivative have been prepared from methyl β-D-galactopyranoside through a sequence involving the bisglycoside methyl 2,6-di-O-benzyl-5-O-methoxv-β-D-galactopyranoside8, the precursor of L-orabino-hexos-5-ulose, that was converted to the L-lyxoseries by inversion at C-3. The inversion was achieved in acceptable yields by selective triflation, followed by displacement with benzoate, and by an oxidation/reduction sequence. Whereas 2,5-di-O-benzyl-L-lyxo-hexos-5-ulose exists entirely as a mixture of the two anomeric 1,4-furanosic forms, the unprotected hexos-5-ulose involves at equilibrium in CD3CN/D2O at least eight tautomers, one of which is predominant.
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