Methyl p-D-glucopyranoside

Methyl-p-D-glucopyranoside Methyl-a-D-glucopyranoside Minor product Major product... 

Methyl-p-D-glucopyranoside (9.7 g) was benzylidenated as described in the foregoing. After removal of the solvents, the cake of product was broken up with a spatula, and dissolved in a solution of sodium hydrogen carbonate (1 g) in water (150 mL) and ethanol (150 mL) by heating on a boiling-water bath. The solution was cooled to 4°C, and compound 20 was filtered off, washed well with water, and dried for 30 h at 30°. The product (8.2 g, 58%) had an m.p. of 207-208.5°C (unchanged by recrystallization from ethyl alcohol) and [ajp —76° (c 1.0, methanol). 

D. Reaction of Methyl p-D-Glucopyranoside with Sulfuryl Chloride [47]... 

From methyl a-D-glucopyranoside, 55% of 2-O-benzyl and 18% of 3-O-benzyl derivatives could be obtained using 1,4-dioxane as a solvent. No monobenzyl derivative was observed under standard DMF solvent conditions [131]. Conformational equilibria 4Ct XC4 play a role in the results of alkylation of all-equatorial methyl P-D-xylopyranoside and methyl P-D-glucopyranoside [131]. 

Carbon-1 of methyl p-D-glucopyranoside is an acetal carbon. In solution, it is not in equilibrium with an open-chain aldehyde. Therefore, it cannot reduce Ag+ or Cu2+ and does not give positive tests with Tollens , Fehling s, or Benedict s reagent. 

Figure 3. Partial 100-MHz 2H NMR spectra of methyl p-D-glucopyranoside, showing the single selective determination of the spin-lattice relaxation rate of H-l using a two-pulse inversion recovery sequence. All spectra were monitored as for those in Figure 2 except for pulse delay — 25 sec. The duration of the selective 180°-pulse was 38 msec (13 Hz bandwidth). The time interval (sec) between the selective 180°- and 90° -pulses are indicated to the right of each...

Physical studies on glycosides have included the X-ray diffraction analysis of methyl a-D-galactopyranosides and methyl p-D-glucopyranosides with fatty acid esters at C-6 which showed bilayer structures with zig-zag alkyl chains. The conformational behaviour of several non-ionisable lactose analogues have been examined by NMR and molecular mechanics methods, and the energy profile of methyl p-D-arabinofuranoside as a function of ring conformations has been determined by gas phase computations. ... 

The experimental results were in full agreement with the above predictions. The sodium borohydride reductimi in methanol of methyl 4, 6-0-benzylidene-3-C>-methyl-p-D-arabino-hexopyranosid-2-ulose 33 gave a crude reduction product that consisted almost exclusively of methyl 4, 6-0-benzylidene-3-0-methyl-a-D-mannopyranoside 35 (Fig. 1.8) (the manno to gluco ratio was 19 1). The sodium borohydride reduction of methyl 4,6-0-benzylidene-3-t)-methyl-a-D-arab//i >-hexopyranosid-2-ulose 34 in methanol afforded methyl 4, 6-0-benzylidene-3-(9-methyl-p-D-glucopyranoside 36 as the only product. 

Table 3.6 Rates of hydrolysis in 0.5M sulfuric acid, at 70° of monomethyl ethers of methyl-p-D-glucopyranoside [22]...

Tri-Me, H-benzoyl Benzyl 2-benzamido-2-deoxy-3,4,6-tri-O-methyl-p-D-glucopyranoside... 

---