Methyl-p-D-xylopyranoside

Xylan fragments induced xylanase also in non-cellulolytic microorganisms like Streptomyces sp. (71) and yeasts of the genus Cryptococcus and Trichosporon (72-74). In these strains xylanase could be efficiently induced also by methyl P-D-xylopyranoside, which is extremely slowly metabolized in the cells (72-74). TTie glycoside accelerated xylanase production in hyperproducing color variants of A. pullu-lans (75) and in several strains of Aspergillus (70). Low cost and easy preparation of methyl p-D-xylopyranoside favors its use for large-scale xylanase production. 

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]. 

Just as in the case of nucleosides, the older results were re-investigated with novel methods also for tritylation of pyranosides. All the monotrityl ethers of methyl p-D-xylopyranoside and methyl oc-D-xylopyranoside have been isolated recently [311] to complement the pioneering work by Hockett and Hudson [312], The monotrityl fraction obtained [313] from methyl a-L-fucopyranoside was now found [314] to consist of 2-0- and 3-0-trityl derivatives in the ratio of 3 2 (D-enantiomer has been actually studied). 

Table 4 Relative Reactivities of Hydroxyl Groups in Methyl a- and P-o-Glucopyranosides (MG), Methyl-a-o-Mannopyranoside (MM), and Benzyl-4-O-Methyl p-D-Xylopyranoside (BX) Toward Methylation or Reaction with N.yV-diethylaziridinium Chloride (DAC)... 

Selective Bu2SnO-catalysed monosulfonylation of methyl a-D-xylopyranoside gave 70% of the substitution at 0-2, while similar sulfonylation of methyl p-D-xylopyranoside gave 90% of the esters at 0-4. TSAO-T 38 and TSAOm -T 39, which have internal sulfonate ester moieties, are potent, selective HIV-I reverse transcriptase inhibitors. New analogues were made by the conversion of the alcohol (40, = OH) to esters, carbamates and thiocarbamates (R =... 

Di-0 methyl-p-D-xylopyranoside] [129393-26-6]. Laeviuscoloside H C34H58O10 M 626.826 Constit. of Henricia laeviuscola. 

Methyl-p-D-.xylopyranoside], 15-sulfate [ 129369-37-5]. Laeviuscoloside D C34H560,3S M 704.875 Constit. of Henrida laeviuscola. 

Benzyl 3-bromo-3-deoxy-2-0-methyl-p-D-xylopyranoside, B-103 Benzyl 3-bromo-3-deoxy-4-0-methyl-p-D-xylopyranoside, B-103 Benzyl 3-deoxy-3-fluoro-p-D-glucopyranoside, D-89 Benzyl 3-deoxy-3-iodo-p-L-xylopyranoside, D-280 Benzyl 2,4-di-D-benzoyl-3-bromo-3-deoxy-a-D-xylopyranoside, B-103 Benzyl 2,4,6-tri-D-acetyl-3-deoxy-3-fluoro-p-D-glucopyranoside, D-89 1 - O -Benzyl-3-deoxy-3-fluoro-D-fructose, D-74 3-Bromo-3-deoxy-l,2 5,6-di-0-isopropylidene-a-D-allofuranose, B-56 3-Bromo-3-deoxyglucose D-form, B-75 3-Bromo-3-deoxymannose D-form, B-88 3 -Bromo-3 -deoxythymidine 5 -Trityl, B-99 3 -Bromo-3 -deoxythymidine, B-99... 

Alkyl a- and p-hexopyranosides with protected primary hydroxyl groups were, as a rule, selectively acetylated at 0-2 and 0-3, respectively, by vinyl acetate and Pseudomonas cepacia lipase the effects of variations in the size and hydrophobi-city of the anomeric and primary substituents on the regioselectivity of these reactions have been discussed in terms of enzyme-substrate binding. Methyl P-D-ribopyranoside, methyl P-D-arabinopyranoside, methyl P-D-xylopyranoside, and methyl-a-L-rhamnopyranoside were all acetylated at 0-4 by lipases from... 

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