Hexosyl bromide

Methyl 2-deoxy-39496-tri-0-p-nitrobenzoyl-p-T>- yxo-hexoside. A solution of 370 mg. of 2-deoxy-3,4,6-tri-0-p-nitrobenzoyl- -D-Zyxo-hexosyl bromide (5) in 15 ml. of dry dichloromethane is added to a stirred suspension of 500 mg. of silver carbonate in 100 ml. of absolute methanol. The mixture is stirred for 20 hours and filtered the silver salts are washed several times with warm dichloromethane. The combined filtrate and washings are evaporated to dryness under diminished pressure, and the residue is recrystallized five times from ether-dichloromethane, giving 61% of pure product, having m.p. 173°-174°C. and [ ]D + 36° in chloroform. 

Zorbach and coworkers180 obtained methyl 2-deoxy-a- and /J-D-ribo-hexosides (a /3 = 3 17) by treatment of 2-deoxy-3,5,6-tri-0-(p-nitro-benzoyl)-a-D-nbo-hexosyl bromide with methanol in the presence of silver carbonate. 

Glycosyl nitriles have been synthesized as precursors of C-gtycosyl derivatives. The 2-azido-2 deoxy hexosyl bromides (76) and (77), obtained as a separable mixture firom D-glucal triacetate (i,NaN3 Ce(NH4)2(N03)g ii, LiBr) were converted [Hg(CN)2-PhN02] into the nitriles (78 a , 2 1) and (79), respectively. SimQar results were achieved starting from D-... 

In the field of 2-aniino-2-deoxY-D-glucose disaccharides the sugar in various derivatised forms has been linked to D-galactose (/9-1,3-link)(and /9-1,6-link),D-glucose (iS-l,3-link), 2-amino-2-deoxy-D-glucose (j8-l,4-link) D-galacturonic acid fi-1,2-link)and L-iduronic acid (a-l,4-link).The 2-amino-2,4-dideoxy-4-fluoro compound (55) has been prepared by the oxazoline method and 2-amino-2-deoxy- -D-mannopyranosyl disaccharides have been produced from oximo-products obtained by use of a 2-deoxy-2-oximo-D-arabino-hexosyl bromide. A 4-amino-4-deoxy-D-rhamnosyl disaccharide (a-l,2-linked) has been made by way of 4-azido-corapounds. 

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