Synthesis 2023; 55(07): 1087-1111
DOI: 10.1055/s-0042-1751394
paper

Synthesis of the Three Most Expensive l-Hexose Thioglycosides from d-Glucose

Fruzsina Demeter
a   Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
,
Attila Bényei
b   Laboratory for X-ray Diffraction, Department of Physical Chemistry, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
,
Anikó Borbás
a   Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
,
Mihály Herczeg
a   Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary
c   Research Group for Oligosaccharide Chemistry of Hungarian Academy of Sciences, ELKH, Egyetem tér 1, 4032 Debrecen, Hungary
› Author Affiliations
The authors gratefully acknowledge financial support for this research from the Premium Postdoctoral Program of the Hungarian Academy of Science (PPD 461038, M.H.), the National Research and Development and Innovation Office of Hungary (FK 137924 M.H., K 132870, A.B. and NN 128368), and from the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.4-15-2020-00008.


Abstract

The biologically important l-hexoses, which are less widespread than d-hexoses, cannot be obtained from natural sources or can only be extracted very costly. Due to the complexity of their synthesis, their commercially available derivatives (which are sold mostly in free form) are also very expensive, which is further exacerbated by the current rapid rise in prices. In the present work, starting from the cheapest d-hexose, d-glucose, using inexpensive and readily available chemicals, a reaction pathway was developed in which the three most expensive l-hexoses (l-idose, l-altrose, and l-talose) were successfully prepared in orthogonally protected thioglycoside form, ready for glycosylation. The l-ido and l-talo derivatives were synthesized by C-5 epimerization of the corresponding 5,6-unsaturated thioglycosides. From the l-ido derivatives, the orthogonally protected thioglycosides of l-altrose were then prepared by C-4 epimerization. Different approaches to the preparation of the key intermediates, 5,6-unsaturated thioglycoside derivatives, were systematically investigated in the presence of various protecting groups (ether and ester) and using commercially available reagents.

Supporting Information



Publication History

Received: 30 August 2022

Accepted after revision: 21 November 2022

Article published online:
21 December 2022

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