Glucopyranoside methyl 4,6-0-isopropylidene

RX. n-butyl bromide n-dodecanyl iodide cyclohexyl iodide ethyl bromo acetate methyl 2,3-di-O-acetyl-4-O-benzoyl-6-bromo-6-deoxy-ot-D-glucopyranoside methyl 2,3,4-tri-0-acetyl-6-deoxy-6-iodo-0 -D glucopyranoside l,2 3,4-di-0-isopropylidene-6-deoxy-6-iodo-a-D-galactopyranose methyl 2(R)-[(tert-butoxycarbonyl)amino]-3-iodo-propionate cyclic bis(trifluoromethyl)oxazolidinone bromide. 

Potassium fluoride in 1,2-ethanediol has further been used, as, for example, in the preparation of 5-deoxy-5-fluoro-D-ribose from methyl 2,3-0-isopropylidene-5-0-(methylsulfonyl)-a-D-ribofuranoside,87 and of 6-deoxy-6-fluoro-D-glucose from methyl 6-O-p-tolylsulfoiiyl-a-D-glucopyranoside.77 In one study of primary fluorinations with potas-... 

Stoicheiometric RuOyCCl was also used to oxidise several furanoses, partially acylated glycosides and l,4 3,6-dianhydrohexitols [317] pyranosides to pyrano-siduloses [313] methyl 2,3,6-tri-O-benzoyl-a-D-glucopyranoside and its C-4 epimer to the a-D-xy/o-hexapyranosid-4-ulose (Table 2.3) [317], and methyl 2,3,6-trideoxy-a-D-e 7f/tro-hexapyranoside to the -a-D-,g/yceri9-hexa-pyranosid-4-ulose, an intermediate in the synthesis of forosamine [318], It was also used to oxidise benzyl 6-deoxy-2,3-0-isopropylidene-a-L-mannopyranoside to the a-L-/yxo-hexapyranosid-4-ulose [319] and for oxidation of isolated secondary alcohol functions, e.g. in the conversion of l,6-anhydro-2,3-0-isopropylidene-P-D-man-nopyranose to the-P-D-/yxo-hexa-pyranos-4-ulose mannopyranose (Fig. 2.16, Table 2.3 [20, 320, 324]). 

Only relatively few displacements of chloro groups in carbohydrate derivatives have been reported. Treatment of 6-chloro-6-deoxy-l,2 3,5-di-O-isopropylidene-a-D-glucofuranose (22) with anhydrous hydrazine for 2 days at reflux temperature yielded the corresponding 6-deoxy-6-hydrazino derivative.47 The chloro group in methyl 6-chloro-6-deoxy-a-D-glucopyranoside could be displaced by a benzoate group to afford methyl 6-O-benzoyl-a-D-glucopyranoside, in 74% yield, by... 

The formation in low yield of 3,6-anhydro-4,5-0-isopropylidene-D-allose dimethyl acetal (82), together with methyl 3-O-p-tolylsulfonyl-D-glucopyranoside (83) as the main product, by the action of boiling 2% methanolic hydrochloric acid (under reflux for 27 hours) on 1,2 5,6-di-O-isopropylidene-3-O-p-tolylsulfonyl-a-D-glucofuranose (81) has been reported.87... 

The conversion of 3-amino-3-deoxy sugars into pyrrolidines requires the presence of a leaving group, such as a p-tolylsulfonyloxy group on C-6 this is exemplified by the conversion of 3-azido-3-deoxy-l,2-0-isopropylidene-6-0-p-tolylsulfonyl-a-D-glucofuranose (44) and methyl 3-azido-2-benzamido-2,3-dideoxy-6-0-p-tolylsulfo-nyl-j8-D-glucopyranoside (46) into the respective pyrrolidines, 45 and 47, by reduction of the azido group, followed by cyclization.37... 

Compound 177 was purified through the corresponding methyl /3-L-glucopyranoside by treatment with methanol, ether, and silver carbonate (overall yield 42%). The same reaction was applied186 to methyl 5-0-benzoyl-2,3-0-isopropylidene-a-D-lyxofuranoside (178), which gave the bromide 180 (crude yield 98%). Evidently, com-... 

Sometimes, an extraneous, dry, inert or non-polar solvent1 16 70 is added. Thus, methyl tetra-0-/3-naphthylsulfonyl-a-D-glucopyranoside was synthesized14 in quinoline-chloroform at 40°, and cellulose was sulfonylated 71 by means of a sulfonyl halide plus pyridine, quinoline, triethylamine, or diethylaniline, in the presence of nitrobenzene or other indifferent solvent. Raymond and Schroeder72 successfully employed acetone as added solvent in tosylation of l,2 3,4-di-0-isopropylidene-D-... 

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