Synthesis of N-Troc Sialyl Donor

Special precautions Do not alkahze the reaction mixture of the deacetylation at the workup to prevent the formation of 4,5-oxazohdinone derivative. It is noteworthy that the resulting N-hydroxysucdnimide (SuOH) should be extracted with water from the reaction mixture because SuOH is hard to remove by chromatographic separation after the acetylation. 

Procedure Add dry methanol (343 ml) to a flask containing phenylthioglyco-side of 4,7,8,9-tetraacetyl-Neu5Ac (20.0 g, 34.3 mmol), and then add methane-sulfonic acid (6.7 ml, 102.9 mmol). Leave the solution refluxing for 21 h. The 

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