反应详情

A solution of 1,2,3,4-tetra-O-acetyl-α-L-fucopyranose (6.00 g, 18 mmol), prepared, for example, according to Nunez et al., supra., and hydrazine acetate (1.99 g, 21.6 mmol) in 20 ml of dry dimethylformamide is stirred at 50° C. for 4.5 h. After addition of ethyl acetate, the mixture is extracted about twice with aqueous sodium chloride solution and the concentrated organic extract is chromatographed (petroleum ether (40°-60°)/ethyl acetate 1:1). 2,3,4-Tri-O-acetyl-L-fucopyranose (1) is obtained in an anomer ratio of α:β of 3:1 with a yield of 80%. TLC analysis (petroleum ether (40°-60°)/ethyl acetate 1:1) gives Rf =0.47.

1. extractionthe mixture is extracted about twice with aqueous sodium chloride solution
2. extractionthe concentrated organic extract
3. customis chromatographed (petroleum ether (40°-60°)/ethyl acetate 1:1)