Methyl D-glucopyranosides

Scheme 11). For methyl (methyl D-glucopyranosid)uronate (27a,b), a-cleavage is accompanied by a rearrangement70 initiated by hydrogen abstraction from the solvent (Scheme 12). 

Scheme 12.—Proposed Mechanism for Photochemical Reactions of Methyl (Methyl D-Glucopyranosid)uronates (27a,b).

Table II Quantitative Effects of a-Methyl-D-glucopyranoside Analogues as Acceptors in the B-512F Dextransucrase Reaction...

Relative efficiency determined by comparing the amount of dextran s3mthesized in the presence of each analogue to the amount synthesized in the presence of o-methyl-D-glucopyranoside and assigning 100% efficiency to a-methyl-D-gluco pyranoside. 

An example of glucosides is a-Methyl-d-glucopyranoside Tetranitrate, Q3N0CH3CH0[CH(ONO2)]3CHOCH3 mw 374.18,... 

The results obtained in the methyl D-glucopyranoside series were thoroughly extended to other benzylidene acetals. From methyl 4,6-O-benzylidene-a-D-galactopyranoside (22), the expected 6-bromo derivative 80 was obtained in high yield (90%),116 and methyl 2,3-di-O-... 

The applications mentioned are well illustrated by the following example. Methyl-/ -D-glucopyranoside 2,3-dinitrate was converted in the presence of methyl iodide and silver oxide into the 4,6-dimethyl ether of the above nitrate, whereupon it was treated with trityl chloride and acetic anhydride in pyridine eventually yield methyl... 

Methyl fluoroform, t291 Methyl 2-furancarboxylate, m253 5-Methylfurfural, m251 a-Methyl-D-glucopyranoside, m256... 

In a 100-ml conical flask place 5.5 g (0.015 mol) of methyl 2,3,4,6-tetra-O-acetyl-/ -D-glucopyranoside (Expt 5.111), 50 ml of dry methanol and 10ml of a solution of sodium methoxide in methanol previously prepared by the cautious addition of 0.1 g of sodium to 20 ml of methanol. Stopper the flask and allow the solution to stand for 1 hour, then add sufficient ion exchange resin [Zeolite 225 (H )] to render the solution neutral to moist universal indicator paper. Remove the resin by filtration, wash with methanol and evaporate the combined filtrate and washings under reduced pressure (rotary evaporator). Triturate the colourless syrup with absolute ethanol to cause it to solidify and recrystallise from absolute ethanol. The pure methyl / -d-glucopyranoside has m.p. 108-109 °C, [oc]d° —30.2° (c2.8 in H20) the yield is 2.4 g (83%). 

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