ISSN:
1573-4986
Keywords:
Glycoside synthesis
;
nitrile effect
;
sialyl donors
;
sialyl phosphites and phosphates
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The importance and requirements for catalytic activation of sialyl donors are discussed, leading to the acid sensitive phosphite and phosphate moiety, respectively, as leaving group and nitriles as solvent. Therefore, from readily availableN-acetylneuraminic acid, derivative1 with phosphochloridites2a-f and Huenigs' base sialyl phosphites3a-f were prepared and isolated in high yields. Oxidation of3a, c withtert-butyl-hydroperoxide afforded the corresponding phosphates4a, c. As expected, phosphites3 could be activated in acetonitrile by catalytic amounts of TMSOTf; thus, from3a-e as donors and lactose derivatives8A, B as acceptors the ganglioside building blocks9A and9B, respectively, were obtained in good yields. The best results were obtained with diethyl phosphite derivative3a as sialyl donor, which exceeded by far the reults obtained with the corresponding phosphate derivative4a. Trisaccharide9B was transformed into known9A and into the fullyO-acetylated GM3-trisaccharide10.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00731182
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