Ultrasonic Agitation Accelerates cis-Glycosylation with Heterogeneous Promoters

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Title:Ultrasonic Agitation Accelerates cis-Glycosylation with Heterogeneous Promoters
Creators:
Whitfield, Dennis M.
Meah, M. Younus
Křepinský, Jiří J.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 58, 1, pp. 159-172

Abstract

Ultrasonic agitation increases the yield of glycosylations with donors such as 3,4,6-tri-<i>O</i>-acetyl-2-azido-2-deoxy-α-D-galactopyranosyl chloride using the heterogeneous promoters silver zeolite, cadmium zeolite or a mixture of silver perchlorate and silver carbonate on celite. The stereospecificity of the glycosylation depends on the nature of the alcohol to be glycosylated, the nature of the solid support and the solvent. Glycosylation catalyzed by silver zeolite in toluene solutions of the donor 3,4,6-tri-<i>O</i>-acetyl-2-deoxy-2-phtalimido-β-D-glucopyranosyl bromide, that usually produce <i>trans</i>-β-glycosides, yield <i>cis</i>-glycosides with unreactive alcohols. In these unreactive alcohols, e.g. methyl 2-<i>O</i>-benzoyl-4,6-<i>O</i>-benzilidene-β-D-galactopyranoside and benzyl 3,4,6-tri-<i>O</i>-benzyl-α-D-mannopyranoside, the hydroxyls to be glycosylated are hydrogen-bonded to a <i>cis</i> vicinal oxygen. This feature was evident in their AM1 minimized conformations and was indicated by the solution <i>J</i>(OH,CH) <sup>1</sup>H NMR coupling constants.

Title:Ultrasonic Agitation Accelerates cis-Glycosylation with Heterogeneous Promoters
Creators:
Whitfield, Dennis M.
Meah, M. Younus
Křepinský, Jiří J.
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:58
Number:1
Page Range:pp. 159-172
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19930159UNSPECIFIED
ID Code:138
Item Type:Article
Deposited On:06 Feb 2009 16:58
Last Modified:06 Feb 2009 15:58

Citation

Whitfield, Dennis M.; Meah, M. Younus; Křepinský, Jiří J. (1993) Ultrasonic Agitation Accelerates cis-Glycosylation with Heterogeneous Promoters. Collection of Czechoslovak Chemical Communications, 58 (1). pp. 159-172. ISSN 0010-0765

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