38] - Amino Sugars via Displacement of Sulfonyloxy Groups with Hydrazine: Methyl 4-Amino-4,6-dideoxy-2,3-O-isopropylidene-α-L-talopyranoside and Methyl 2,6-Diacetamido-2,6-dideoxy-3,4-O-isopropylidene-α-D-allopyranoside

Abstract

Publisher Summary This chapter focuses on the synthesis of amino sugar derivatives by replacing р-tolylsulfonyloxy (tosyloxy) groups with hydrazine and subsequent reduction of the hydrazino compounds. Highly concentrated hydrazine (> 95%) can be obtained by distillation of ∼ 85% hydrazine hydrate over sodium hydroxide. Anhydrous hydrazine can be easily prepared from hydrazine sulfate and liquid ammonia by a modification of the method of Browne and Welsh, which avoids heating above room temperature. In some cases, replacement with hydrazine gives better results than replacement with azide or ammonia. When two tosyloxy groups have an appropriate steric arrangement, cyclization to an imino derivative takes place.