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Ring Opening of Benzyl β-D-Galactoside Cyclic Sulfates into Galactose Monosulfates. New Access to 6-Deoxy-Galacto-Hex-5-Enopyranoside and 4-Deoxy-3-Ketogalactopyranoside.
Titel:
Ring Opening of Benzyl β-D-Galactoside Cyclic Sulfates into Galactose Monosulfates. New Access to 6-Deoxy-Galacto-Hex-5-Enopyranoside and 4-Deoxy-3-Ketogalactopyranoside.
Auteur:
Dagron, Franck Lubineau, Andre
Verschenen in:
Journal of carbohydrate chemistry
Paginering:
Jaargang 19 (2000) nr. 3 pagina's 311-321
Jaar:
2000
Inhoud:
The behavior of 3,4- and 4,6-cyclic sulfates derived from benzyl 2,6- and 2,3-di-O-benzyl-β-D-galactopyranosides toward hydrolysis has been studied using aqueous sodium hydroxide under various conditions. Starting from benzyl 2,6-di-O-benzyl-3,4-O-sulfuryl-β-D-galactopyranoside (5), the reaction with aq NaOH in THF gave both 3- and 4-monosulfates 7 and 8 (83%, in 68:32 ratio), while the reaction in DMF led unexpectedly to the 4-deoxy-3-keto derivative 10 in 77% yield after acidic hydrolysis of the intermediate enolester 9. On the other hand, when benzyl 2,3-di-O-benzyl-4,6-O-sulfuryl-β-D-galactopyranoside (6) was treated with aq NaOH in THF, a mixture of benzyl 2,3-di-O-benzyl-6-deoxy-4-O-(sodium sulfonato)-α-L-arabino-hex-5-enopyranoside (11) and benzyl 2,3-di-O-benzyl-4-deoxy-6-O-(sodium sulfonato)-α-L-threo-hex-4-enopyranoside (12) (in 65:35 ratio) was obtained in 93% yield, giving a new and rapid access to 11, a potential precursor of L-sugars derivatives. Alternatively, BzONBu4 gave a regiospecific opening reaction of 6 and led to the 6-O-benzoate 4-O-sulfate derivative (13) in excellent yield.
Uitgever:
Taylor & Francis
Bronbestand:
Elektronische Wetenschappelijke Tijdschriften
Details van artikel 134 van 252 gevonden artikelen
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