A-D-Glycopyranosides

According to van deer Veen (27) and Rao and Foster (17 the anomeric proton line positions for a-D-glycopyranosides (H equatorial) appear in the region of 4.8 to 5.5 p.p.m., while for / -D-glycopyranosides (Hi axial), the peaks appear at 4.4 to 4.6 p.p.m. The chemical shift of the anomeric proton of methylkasugaminide (5) is located at 4.57 p.p.m. and thus the proton must be axial, excluding structure 8b and 8c in which the anomeric proton is equatorial. Structure 8a is thus completely in agreement with the NMR spectra. 

The 18-crown-6 derivatives (obtained from the methyl 4,6-0-benzylidene-a-D-glycopyranosides) such as a-D-206 with both KI (206) and KSCN (207), aa-DD-115 (Figure 18) in its fiee form (150), and a-o-103 (Figure 17), a-d-105 (Figure 17), and aa-DD-119 (Figure 18) with BH3NH3 (208). 

J. M. Williams and A. C. Richardson, Selective acylation of pyranosides I. Benzoylation of methyl a-D-glycopyranosides of mannose, glucose and galactose, Tetrahedron, 23 (1967) 1369-1378. 

The first synthesis of methyl 4-thiomaltoside (36b) (34%), 4-thiocellobioside (39d) (52%) and 4-thiodigalactobioside (86) (56%) was reported 18 years ago by using the Sn2 displacement of 1,2-cis- or 1,2-trans- glycosyl halides (9 a), (7 a) and (7c) with methyl 4-thio-a-D-glycopyranoside sodium salts generated from the acetylated methyl glycosides (84) and (85a) (Scheme 25) [14a]. 

However, it is not applicable when the alcohol cannot be used as the solvent, as in a cholesteryl a-D-glycopyranoside, for example. In this instance, the alternative glycosyla-tion method with 0-benzyl protective groups could be problematic because of the de-benzylation step in the presence of the A-5 double bond in the aglycone. 

Synthesis of Alkyl 2-Deoxy-a-D-glycopyranosides and Their 2-Deuterio Derivatives, R. U. Lemieux and S. Levine, Can. J. Chem., 42 (1964) 1473-1480. 

When pentaacetylpseudocellobial is treated with methanol and hydrogen chloride, the methyl a-D-glycopyranoside of pseudocellobial (LXX) is... 

Trichloroacetimidates may alo be used for the synthesis of 2-amino-2-deoxy-a-D-glycopyranosides particularly in the galactose series.36... 

Wu X and Zhou W 1991 Fermentation monitoring and control by on-line flow injection and liquid chromatography Anal. Chim. Acta 249 87-100 [ 16] Holm K A 1986 Automated spectrophotometric determination of amyloglucosidase activity using p-nitrophenyl-a-D-glycopyranoside and a flow injection analyzer Analyst 111 927-9... 

Other Alkyl and Aryl Ethers - A number of 3-0-aminoalkyl-l,2-0-isopro-pylidene-a-D-gluco-or xylo-furanoses have been synthesized and evaluated for antiviral activity. Some 6-0-alkyl-a-D-glycopyranosides have been prepared by displacement of 6-0-tosylates with alkoxides, while the regioselectivity of 3- or 5-0-ether formation on l,2-0-isopropylidene-4,6-di-0-benzyl-/n> o-inositol has been shown to depend on the nature of the 0-alkylating agent. A facile synthesis of methyl 2-or 3-0-allyl-5-0-benzyl-p-D-ribofuranoside has been described. ... 

Synonyms 2-Hydroxymethyl-6-methoxytetrahydropyran-3,4,5-triol a-Methyl-D-glucoside Methyl-a-d-glycopyranoside ClassiTication Nonaromatic alcohol Empirical C,H 06... 

Methyl glycocoll. See Sarcosine Methyl glycol. See Propylene glycol Methyl glycol acetate Methyl glycol monoacetate. See Methoxyethanol acetate Methyl-a-d-glycopyranoside. See a-Methyl glucoside... 

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