Xylosides synthesis

Honeyman147 reported the synthesis of methyl 2,3-anhydro-/3-L-lyxopyranoside, and claimed that, on alkaline hydrolysis, this gives a 2 1 ratio of L-xyloside L-arabinoside, but these results could not be substantiated by Buchanan and R. Fletcher,68 who recorded different constants for the epoxide and for the disulfonic ester claimed147 to be the starting material for its synthesis. The same epoxide has been synthesized by Reist and coworkers,160 and its properties are in agreement with Buchanan and Fletcher s results. Ethyl or methyl 3,4-anhydro-/3-L-ribopyranoside undergoes substitution at C-4 in all the reactions thus far studied. Neither half-chair conformation would seem to be clearly favored, but the specificity observed can be rationalized by considering the steric and polar interactions that may arise in the transition state substitution at C-3 in conformation 58 would involve marked interactions between the nucleophile and... 

The anionic groups observed in basement membrane with cationic stains were identified as heparan sulfate chains on the basis of their sensitivities to heparitinase and to nitrous acid (Kanwar and Farquhar, 1979b) and by chemical analysis (Kanwar and Farquhar, 1979c Parthasarathy and Spiro, 1982). Current concepts suggest that the heparan sulfate chains are linked through a common oligosaccharide terminating in xylose linked to serine residues on the protein core and that certain xylosides can act as initiators for the synthesis of heparan sulfate. In the absence of added xyloside, the synthesis of heparan sulfate is entirely dependent on the synthesis of a core protein. 

The synthesis of 3,4-dimethyl-D-xylose had previously been recorded10 but no direct comparison of similar derivatives of the natural and synthetic product had been made. For the synthesis, methyl 3,5-isopropyli-dene-D-xyloside (a/3 mixture) was converted into the 2-benzoate (XV) which with hot methanolic hydrogen chloride was transformed (presumably) into methyl 2-benzoyl-D-xylopyranosides (a/3 mixture) (XVI)... 

Nakamura, T. Toshima, K. Matsumura, S. One-step synthesis of n-octyl (3-D-xylotrioside, xylobioside and xyloside from xylan and n-octanol using acetone powder of Aureobasi-dium pullulans in supercritical fluids. Biotechnol. Lett. 2000, 22 (14), 1183-1189. 

Figure 6 Three lipophilic /3-D-xylosidesthat inhibit GAG synthesis (a) 3-estradiol-/3-D-xyloside, (b) 2-naphthol-/3-D-xyloside, and (c) 3-D-equilenin-/3-D-xyloside.

Takanashi, S.I., and K. Mori, Synthesis of the Analogues of Lurlenic Acid with a Modified Sugar Part Chlamydomonas Responds Only to the D-Xyloside, Liebigs Ann./Recueil, 1081-1084 (1997). 

The leaf-closing substance 79 has been isolated from a nyctinastic plant," and compound 80 is a new lignan glycoside isolated in tiny proportions from the roots of Saussurea lappa Xyloside 81 is a new glycoside isolated from the mycelia of Hericium erinaceum which contains compounds that stimulate nerve growth factor synthesis. Two derivatives were made by chemical transformations. 

While much of the work reported so far on alkyglycosides has dealt with hexose sugars, there are a few reports on the synthesis of pentose-based alkyglycosides that are effective next-generation surfactants. Starting from xylan, alkyl-/3-xyloside and -yS-D-xylobioside were produced by partial hydrolysis and simultaneous transglycosylation to various alcohols in a reaction catalysed by acetone powder of Aureobasidium pullulans cells with xylanase activity [77], The yield of the xyloside product increased while that of the xylobioside decreased with time and with an increase in concentration of the cells. The product yields were significantly improved and even alkyl-yS-xylotrioside was formed when the reaction was performed in supercritical fluids [78]. 

Jiang, Z., Zhu, Y., Li, L., Yu, X., Kusakabe, L, Kitaoka, M. Hayashi, K. (2004). Transglycosylation reaction of xylanase B from the hyperthermophilic Thermotoga maritima with the ability of synthesis of tertiary alkyl P-D-xylobiosides and xylosides. Journal of Biotechnology, 114, 125-134. 

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