3- methoxy-2-pyridyl glycoside

General Procedure for the Preparation of Partially Acylated MOP Glycosides 3-Methoxy-2-pyridyl 2,3,4-tri-O-p-fluorobenzoyl-fi-D-glucopyranoside (33)... 

A mixture of 60 mg of 3-methoxy-2-pyridyl 2,3,4,6-tetra-O-acetyl-p-D-glucopyranoside and 120 mg of HgBrj in 3 mL of xylene was refluxed for 5 h. TLC showed most of the starting material was converted into the a-isomer. The solution was cooled to room temperature, filtered over Celite and washed with CH Cl. The filtrate was treated with 10% aqueous NajSjOj, dried over Na2S04, and concentrated. The residue was purified by flash chromatography on silica gel (EtOAc-hexane, 1 4 to 1 2) to give 29 mg of the a-glycoside... 

On the basis of the concept of remote activation [222], first applied to pyridine thiogly-cosides [223], Hanessian and co-workers introduced 3-methoxy-2-pyridyl (MOP) glycosides [224,225]. They first reported the usefulness of ribofuranosyl MOP donor 465 in the coupling with silylated pyrimidine bases, by activation with TMSOTf, to give l,2-d5 nucleosides, 466, with high selectivity (O Scheme 78) [226]. These glycosides react in MeOTf-, Cu(OTf)2-, TfOH-, or Yb(OTf)3-promoted reactions to give disaccharides [227]. 

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