Sucrose, 3 ,6 -anhydro-, synthesis preparation

Internal-displacement reactions to give sugar anhydrides are well known, and anhydro derivatives of sucrose have been prepared by treatment of the respective sulfonates or chlorides with a base. Buchanan and coworkers described the synthesis of 3, 6 -anhydrosucrose by treating 2,3,4,6,l, 3, 4 -hepta-0-acetyI-6 -0-(p-ni-trophenylsulfonyl)sucrose with sodium ethoxide in ethanol for 2 h under reflux.18 Similar treatment of 2,3,4,l, 3, 4, 6 -hepta-0-acetyl-6-chloro-6-deoxysucrose (46) with sodium methoxide in methanol, followed by acetylation, gave crystalline 2,4,l, 3, 4, 6 -hexa-0-acetyl-3,6-anhydrosucrose (47) in 83% yield.81 The H n.m.r. spectrum of 47... 

The reaction of 1,2-anhydro sugars with alcohols promises to be a useful method for the preparation of glycosides. Brigl (S3) prepared methyl iS-D-glucopyranoside 3,4,6-triacetate by evaporating a solution of 1,2-anhydro-3,4,6-tri-0-acetyl-D-glucose in methanol to dryness. Recently, Lemieux and Huber (54) have extended the method to the synthesis of sucrose (see Chapter IX). 

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