Xylopyranoside methyl 5-thio

Glycosides and Simple Derivatives Thereof. — Methyl 2,3,4-tri-O-benzoyl-0-D-xylopyranoside, methyl 2,3,4,5-tetra-0-acetyl-o -D-galactoseptanoside, 2-pyridyl l-thio-/3-D-glucopyranoside, the three methyl xanthates of methyl 4,6-... 

Tetra-O-acetyl-5-thio-a-D-xylopyranose can be transformed into the crystalline a-D-glycosyl bromide (213) by the action of hydrogen bromide in acetic acid. Compound 213 undergoes deacetylation with sodium methoxide to form methyl 5-thio-j8-I>-xylopyranoside (218). In the presence of sodium methoxide and methanethiol, 213 forms methyl l,5-dithio-j8-D-xylopyranoside (219). Compound 219 is so sensitive toward acidic methanol that it is transformed into methyl 5-thio-j3-D-xylopyranoside (218) on neutralization of the basic reaction mixture with an acid ion-exchange resin. 

Whistler, R L, van Es, T, Solvolysis of methyl 5-thio-D-xylopyranosides and 2,3,4-tri-0-acetyl-5-thio-a-D-xylopyranosyl bromide, J. Org. Chem., 28, 2303-2304, 1963. 

A new synthetic route towards naphthyl xylosides was performed on solid support. Pure xylosides were obtained in 6-42% overall yield from the amino-methylated resin [84, 85], Similarly, p-o-xylopyranosides bearing a fluorescent moiety as a probe for proteoglycan biosynthesis [83], bis-xylosylated dihydrox-ynaphthalenes [86] and 2-naphthyl-l-thio-P-o-xylopyranosides were also prepared and these compounds have exhibited a strong pruning of GAG chains biosynthesis [87]. 

Figure 3.21 Time courses of the hydrolysis of an isotopic quasi-racemate in two acid-catalysed hydrolyses of glycosides. Both figures, taken from Ref. 107, by kind permission of Prof. A. J. Bennet and the American Chemical Society, refer to a mixture of labelled d-sugar and unlabelled l-sugar (10mgmL each), show the least-squares best fit and display only every fourth data point for clarity, (a) Ring effect for methyl (3-xylopy-ranoside (b) anomeric effect for methyl 5-thio-oc-xylopyranoside. See Table 3.3 for numerical values of the effects, which are in opposite senses.

The syntheses of 5-thio-D-arabinose and -lyxose have been achieved conventionally by thiocarboxylate displacements on 5-sulphonate ester derivatives of these sugars, and their methyl glycosides were also prepared, both anomers being obtained. Methyl 5-thiopentopyran-osides (D-arabino. L-lyxo, D-ribo. and D-lyxo derivatives) have also been prepared from methyl 5-thio-3-0-tosyl-o<-D-xylopyranoside as outlined in Scheme 1. The syntheses of S-(5 -deoxy-5 -adenosyl)-(+)-2-methylhomocysteine (14.) has been achieved in two steps from (+)-2-methyl-homocysteine. Methyl 2-0-tosyl-4,6-thioanhydro-K-... 

Me glycoside Methyl 3-amino-3-deoxy-5-thio-a-D-xylopyranoside [142544-08-9]... 

Me glycoside, 2,3-O-isopropylidene, 4-Ac Methyl 4-0-acetyl-2,3-0-isopropylidene-1-thio-fS-D-xylopyranoside CiiHigOjS 262.326 Syrup. Mg -90 (c, 1.0 in CHCI3). 

Methyl 4-0-acetyl-2,3-0-isopropylidene-a-L-rhamnopyranoside, M-207 Methyl 5-5-acetyI-2,3-0-isopropylidene-5-thio-a-D-lyxofuranoside, T-80 Methyl 5-5-acetyI-2,3-0-isopropylidene-5-thio-a-L-rhamnofuranoside, T-88 Methyl 4-0-acetyI-2,3-0-isopropylidene-l-thio-p-D-xylopyranoside, T-98 Methyl 2-0-acetyI-4,6-0-isopropylidene-3-0-tosyl-a-D-gulopyranoside, M-194... 

Methyl 4-0-benzoyl-l-thio-a-L-rhaninopyranoside, T-86 Methyl 6-0-benzoyl-2,3,4-tri-0-mesyl-a-D-galactopyranoside, M-185 Methyl 2-0-benzoyl-3,4,6-tri-0-methyl-p-D-glucopyranoside, T-188 Methyl 2-0-benzoyl-6-0-trityl-a-D-glucopyranoside, M-213 Methyl 3-0-benzoyl-a-D-xylopyranoside, M-217 Methyl (benzyl 2,3-di-0-benzyl-a-D-glucopyranosid)uronate, B-17 Methyl (benzyl 2,3-di-0-benzyl-p-D-glucopyranosid)uronate, B-17 Methyl (benzyl 2,3-di-0-benzyl-4-0-mesyl-a-D-glucopyranosid)uronate,... 

Methyl 2,6-di-0-benzoyl-3-0-methyl-p-D-mannopyranoside, M-205 Methyl 3,5-di-0-benzoyl-2-0-methyl-p-D-ribofuranoside, M-208 Methyl 4,6-di-O-benzoyl-2-0-methyl-3-O-tosyl-a-D-altropyranoside, M-149 Methyl 3,5-di-0-benzoyl-p-D-tAreo-pentofuranosid-2-ulose, P-45 Methyl 2,3-di-O-benzoyl-a-L-rhamnopyranoside, M-207 Methyl 2,4-di-O-benzoyl-a-L-rhamnopyranoside, M-207 Methyl 3,5-di-O-benzoyl-p-D-ribofuranoside, M-208 Methyl 2,3-di-O-benzoyl-l-thio-p-L-fucopyranoside, T-63 Methyl 2,3-di-O-benzoyl-l-thio-a-L-rhamnopyranoside, T-86 Methyl 2,3-di-0-benzoyl-5-0-tosyl-a-L-arabinofuranoside, M-152 Methyl 3,5-di-0-benzoyl-2-0-tosyl-p-D-lyxofuranoside, M-201 Methyl 2,3-di-0-benzoyl-4-0-tosyl-a-L-rhamnopyranoside, M-207 Methyl 2,4-di-0-benzoyl-3-0-(2,3,4-tri-0-acetyl-a-L-rhamnopyranosyl)-a-D-xylopyranoside, R-77... 

O -Benzyl-1,2-0 -isopropy lidene- 3- O -methyl-a-i>xylofuranose, 1-76 /er/-Butyl 2,3,4-tri-O-acetyl-l-thio-a-D-xylopyranoside, T-98 /er/-Butyl 2,3,4-tri-0-acetyl-l-thio-p-i>xylopyranoside, T-98 4-Chloro-4-deoxyxylose a-L-Pyranose-ybrm Me glycoside, 2-mesyl,... 

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