173 22 Conversion of Allyl 2-acetamido-2-deoxy- β - D-glucopyranoside to Allyl 2-acetamido-2- deoxy-4,6-di- O -pivaloyl- β - D-galactopyranoside Nicolò Marnoni, Monica Varese, Kottari Naresh, † and Luigi Panza* HO HO OH OAll 1. Tf 2 O CH 2 Cl 2 /Py 20:1 0°C 2. H 2 O, reflux AcNH PivO HO OAll O OPiv 1 76% PivO AcNH OAll HO O OPiv 3 2 86% AcNH PivCl, CH 2 Cl 2 /Py 1:2 0°C O The biological role of oligosaccharides in cell signaling is well established, and interest in such compounds as therapeutics is growing. 1 Therefore, it has become increasingly important to gain access to pure, well-deined, complex carbohy- drates. Chemical synthesis is one among the tools to obtain this class of compounds. N-acetyl-d-galactopyranose glycosylated at O-3 is commonly found in natural, * Corresponding author; e-mail: luigi.panza@pharm.unipmn.it. † Checker, under supervision of Prof. René Roy; e-mail: roy.rene@uqam.ca. CONTENTS Experimental .......................................................................................................... 174 General Methods ............................................................................................... 174 Allyl 2-acetamido-2-deoxy-3,6-di-O-pivaloyl-β-d-glucopyranoside (2) .......... 174 Allyl 2-acetamido-2-deoxy-4,6-di-O-pivaloyl-β-d-galactopyranoside (3) ....... 175 Acknowledgment ................................................................................................... 175 References .............................................................................................................. 178 K18997_C022.indd 173 2/28/2015 5:00:34 PM