Of methyl-a-D-glucopyranoside

The acetylation of methyl-a-D-glucopyranoside with A-acetylimidazole (DMF, room temp., 48 h) affords no significant selectivity, and leads to partial substitution at all four hydroxyl groups (2-OAc 3-OAc 4-OAc 6-OAc = 35 15 20 35). 19 1... 

Although there were early reports on the selective acylation72,73 and p-toluenesulfonylation73 of methyl a-D-glucopyranoside, and the p-toluenesulfonylation of methyl a-D-galactopyranoside,74 to yield... 

The reaction of methyl a-D-glucopyranoside with sulfur monochloride in N,N-dimethylformamide to give the 6-chloro-6-deoxy derivative in 30-35% yield has been described392 it is possible thatN,N-... 

The reaction of sulfuryl chloride with carbohydrates to give chloro-deoxy derivatives has been reviewed briefly in this Series.98 The reaction of sulfuryl chloride with monosaccharides has been shown to afford products in which the secondary hydroxyl groups are replaced by chlorine with inversion of configuration.68-75 Jones and coworkers reported that the reaction of methyl a-D-glucopyranoside with sulfuryl chloride and pyridine in chloroform at room temperature proceeds by way of the 4,6-bis(chlorosulfate) by an Sn2 process, with chloride as the nucleophile, to give methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside 2,3-bis(chlorosulfate).74... 

The aforementioned deuterated derivatives were prepared by way of reduction of a ketone, aldehyde, or ester with sodium borodeu-teride, or by deuteroboration of an alkene. An interesting reaction, perhaps eventually applicable to direct deuteration of polysaccharides, was reported by Koch and Stuart413 and by them and their coworkers,41b who found that treatment of methyl a-D-glucopyranoside with Raney nickel catalyst in deuterium oxide results in exchange of protons attached to C-2, C-3, C-4, and C-6. In other compounds, some protons of CHOH groups are not replaced, but the spectra may nevertheless be interpreted with the aid of a- and /3-deuterium effects. 

Figure 5. The 90° C-13 NMR spectra of methyl a-D-glucopyranoside (the agly-con resonance at S3 ppm is not shown), a branched amylose (sample OAG-II-3), and rabbit liver glycogen...

An X-ray crystallographic analysis has been performed44 on methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside prepared by way of reaction of methyl a-D-glucopyranoside with sulfuryl chloride the molecule has the Cl (d) conformation, and the bond distances and valency angles are similar to those in simple sugars. 

The structures of a- and /3-D-glucopyranose may be compared with that of methyl a-D-glucopyranoside.26 In the latter, the C-l-O-1 bond is shorter than a C-O single bond, but not as short as in a-D-gluco-pyranose. Part of this shortening may affect the C-O bonds of the ring carbon atoms, as the C-l-O-5 bond is slightly shorter than the C-5-0-5 bond. 

Aminoacyl groups were introduced into 2-0- and 3-0-positions of methyl a-D-glucopyranoside. 

Aminoacyl groups were introduced into 2-0-, 3-0-, and 4-0-positions of methyl a-D-glucopyranoside, methyl a-D-galactopyranoside, and methyl a-D-mannopyrano-side. 

The seven-membered ring of methyl a-D-glucopyranoside 2,3-(diphenylcyclodiboronate) 4,6-phenylboronate (34) is selectively... 

A potentially very useful method of protection by use of insoluble polystyrene resins has appeared39 A polymer containing vinylbenzal-dehyde units was used for preparing 4,6-acetals of methyl a-D-glucopyranoside in good yield. 

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