4- O-p-D-xylopyranosyl

The variety of control mechanisms of xylanase synthesis is demonstrated by examples of the synthesis of xylanase induced by xylose (38,74,75). To a list of low-molecular weight xylanase inducers one can add 4-thioxylobiose (80,81) and 4-O-p-D-xylopyranosyl-L-arabinopyranose (73,77). 

Benzyl glycoside, 3-Me Benzyl 5-0-methyl-4-O-(P-D-xylopyranosyl) -P-D-xylopyranoside C18H26O9 386.398 Mg -115 (c, 2.0 in H2O). 

See also under 4-O-p-D-Xylopyranosyl-D-xylose, X-80. Isol. from various acid and enzymic hydrolysates see under 4-0 -P-D-Xylopyranosyl-D-xylose X-80. Cryst. (MeOH). 

O -p-D-Xylopyranosyl-D-allose, X-20 6-0-p-D-Xylopyranosyl-2-amino-2-deoxy-D-glucose, X-21 a-D-Xylopyranosyl-(l 3)-a-L-arabinofuranosyl-(l ->3)-L-arabinose, X-22 p-D-Xylopyranosyl-(l ->3)-a-L-arabinofuranosyl-(l ->3)-L-arabinose, X-23 p-D-Xylopyranosyl-(l ->5)-a-L-arabinofuranosyl-(l ->3)-L-arabinose, X-24 p-D-Xylopyranosyl-(l ->5)-a-L-arabinofuranosyl-(l ->5)-L-arabinose, X-25 p-D-Xylopyranosyl-(l ->3)-a-L-arabinopyranosyl-(l ->4)-[p-D-apiofuraiiosyl-... 

Methyl 2-0-p-D-xylopyranosyl-a-L-arabinopyranoside, 9CI, X-29 Methyl 2-0-p-D-xylopyranosyl-p-L-arabinopyranoside, 9CI, X-29 Methyl 2-0-a-D-xylopyranosyl-p-D-xylopyranoside, 9CI, X-75 Methyl 3-0-a-D-xylopyranosyl-p-D-xylopyranoside, 9CI, X-76 Methyl 4-0-a-D-xylopyranosyl-p-D-xylopyranoside, X-77 Methyl 2-0-p-D-xylopyranosyl-p-D-xylopyranoside, X-78 Methyl 3-O-p-D-xylopyranosyl-p-D-xylopyranoside, X-79 Methyl 4-O-p-D-xylopyranosyl-p-D-xylopyranoside, X-80 4-0-(3-0-Methyl-p-D-galactopyranosyl)-L-rhamnose, G-172... 

The protected 0-glycosyl amino acid ester or O-glycosyl peptide ester (1 mmol) is stirred in morpholine (10 mL) or morpholine-dichloromethane (1 1) for 30 min. After addition of dichloromethane (100 mL), the solution is washed with diluted aqueous acid (citric acid or HCl pH 4, 50 mL) and with water (4 x 50 mL), dried with NajSO, and concentrated in vacuo. The crude product is dissolved in 2-5 mL of ethyl acetate. During chromatography on silica gel (50 g) with petrolum ether ethyl-acetate (2 1), lV-(9-fluorenyImethyl)morpho-line is eluted. Subsequently, the deblocked amino acid or peptide ester is eluted with methanol. 0-(2,3,4-Tri-0-benzoyl-P-D- xylopyranosyl)-L-serine benzyl ester 14 yield, 0.63 g (98%) mp 55°C [a] -41.4 (c 0.5, CHjOH). iV-(L-Asparaginyl-L-leucyl-)-(7-(2,3,4,- -benzoyl-p-D-xylopyranosyl)-L-serine benzyl ester 17 yield, 0.85 g (98%) amorphous (a] -42.3° (c 0.5 CH3OH). 

Benzyl glycoside, 3,4-dibenzyl Benzyl 3,4-di-O-benzyl-2-O-p-D-xylopyranosyl-P-D-xylopyranoside [76490-99-8]... 

P-D-Xylopyranosyl)-L-serine 16. To a solution of O-benzoyl protected xylosyl serine (0.23 g, 0.4 mmol) in methanol (20 mL) is added at room temperature hydrazine hydrate (100%, 20 mL). Monitoring by TLC (ethyl acetate-methanol-water 13 5 2.4) proves the reaction to be complete within 30 min. After 40 min, acetone (50 mL) is added to transform the hydrazine to the acetone azine (which is volatile). After stirring for 1 h, the solution is concentrated in vacuo, the residue is stirred with ethyl acetate to extract impurities and give a pure product yield, 80 mg (86%), mp 215°-218°C (decomposition) reported [39] 230°-235°C, [a] -49.8° (c 0.3, HjO), reported [39] [a], -12° (c 1,0, HjO). 

Abstract—Two new triterpenoid saponins were isolated from the alcoholic extract of roots of Aster auriculatus. Their structures have been determined on the basis of spectral and chemical evidence as 3-0-P-D-glucuronyl-16a-hydroxyolean-12-en-28-oic acid-28-O-a-L-arabino-pyranosyl(l -4)-a-L-rhamnopyranosyl( 1 -2)-3-D-xylopyranosyl-( 1 -3)-P-D-xylopyranosyl( 1 -3)-a-L-arabinopyranoside and methyl ester of 3-0-P-D-glucuronyl-16a-hydroxyolean-12-en 28-oic acid-28-0-P-D-xylopyranosyl( 1 -3)-a-L-arabinopyranosyl( 1 -4)-p-D-apiofiiranosyl( 1 -3)-a-L-rhamnopyranosvK 1 -2)-P-D-xvlopyranoside. ... 

The four saponins are new oleanane saponins. Thdr structures were established as Hemiaria saponin A 28-o- [ a-L-rhamnopyranosyl (l->2) [a-L-rhanmopyranosyl (l->3)]-P-D-xylopyranosyl (l->2)-P-D-fucopyranosyl esto of 3-0-P-D-glucopyranosyluronic (l->4) a-L- rhamnopyranosyl] 2 p, 3 P-dihydroxy oleanl2-en 23,28-dioic... 

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