α- d-allopyranosyl β- d-fructofuranoside ( allo-sucrose) and its derivatives

Abstract

Reduction of 3-ketosucrose ( 1) with sodium borohydride gave mainly α- d-allopyranosyl β- d-fructofuranoside ( 2) characterized as its octabenzoate. Using sodium borodeuteride, [3- 2 H] allo-sucrose ( 5) and [3- 2H]sucrose ( 6) were obtained in the ratio 12:1. The mixture was fractionated on Dowex-50 X8 resin (Ca 2+ form), and the [3- 2H] derivatives were isolated as their octa-acetates. Inspection of the 13C-n.m.r. spectra of 5 and 6 enabled the C-3 signals to be assigned. allo-Sucrose ( 2) was more readily obtained by oxidation of sucrose with dimethyl sulphoxide-acetic anhydride followed by reduction with sodium borohydride and fractionation on Dowex-50 X8 (Ca 2+) resin. Tritylation of 2 followed by acetylation gave, after chromatography, the 6,1′,6′-tritrityl ether ( 9, 10%), the 6,6′-ditrityl ether ( 10, 26%), and a mixture of monotrityl ethers (20%). Hydrogenolysis of 9 and 10 gave the penta-acetate and hexa-acetate, respectively, with no detectable migration of AcO-4. Treatment of 2 with sulphuryl chloride at -50° gave the 6,6′-dichloride.