Sucrose with sodium iodide

Bimolecular nucleophilic displacement reactions of sucrose sulfonates and deoxyhalides have been studied. Treatment of octa-O-(methylsulfonyl)sucrose (S) with sodium iodide in butcinone under reflux gave 6,6 -di-deoxy-6,6 -dideoxy-6,6 -diiodo-1, 2,3,3, 4,4 -hexa-0-(methylsulfonyl)sucrose (T) in 75% yield (26). The... 

Octa-O-methylsucrose has been prepared by treating sucrose with either dimethyl sulfate-sodium hydroxide, or sodium hydride and methyl iodide in A/,A/-dimethylformamide.35... 

Permethylation of sucrose 780 Sucrose (10.2 g) is dissolved in warm dimethylformamide (120 ml b.p. 43-44712 mm) and treated at about 20° with methyl iodide (45 ml). Silver oxide (45 g) is then added with vigorous stirring during about 15 min. After addition of part (about 20 g) of the silver oxide the temperature has risen to about 30°, and care must be taken that the temperature is not exceeded during further additions. When the temperature begins to fall spontaneously (about 40 min after the last addition of silver oxide), the flask is closed and shaken mechanically. The solid material is then separated on a centrifuge and washed with dimethylformamide (50 ml) and chloroform (50 ml). The united solutions are treated with water (500 ml) and potassium cyanide (5 g) and extracted 4-5 times with chloroform (100-ml batches). The united chloroform extracts are washed with 3-4 batches of water (each 100 ml) and dried over sodium sulfate. They yield octa-O-methylsucrose (11.5 g), b.p. 140-145°/0.001 mm, /iD22 1.4559. 

The value of methylation studies in structural determination of carbohydrates is well known. Methylation of sucrose has generally been achieved by the use of dimethyl sulfate-sodium hydroxide,34,35 methyl iodide-silver oxide-acetone,20 sodium hydride-methyl io-dide-N,N-dimethylformamide,35 or diazomethane-boron trifluoride etherate.36,37 The last method (already applied to monosaccharides38,39) has been found particularly useful for sucrose, because it proceeds without concomitant migration of acyl groups. The reaction of 2,3,6,T,3, 4, 6 -hepta-0-acetylsucrose (21) and 2,3,4,6,1, 3, 4 -hepta-O-acetylsucrose (22) with diazomethane in dichloromethane in the presence of a catalytic proportion of boron trifluoride etherate for 0.5 h at —5° gave the corresponding 4-methyl (23) and 6 -methyl (24)... 

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