Lyxoside

Arjunglucosides I (163) and II (164) from Terminalia arjuna are the glucose esters of arjungenin and arjunolic acid respectively. "" The full details of the structure elucidation of arjungenin are included in this paper. Three lyxosides (165)—(167) have been obtained, together with 16a,21/8,22a,28-tetrahydroxyolean-12-en-3-... 

Chart V summarizes the reactions of 2,3- and 3,4-anhydropento-pyranosides. Buchanan and coworkers have shown144 that the methyl 2,3-anhydro-a(and /3)-lyxosides, and 3,4-anhydro-/3-L-arabinoside adopt that half-chair conformation (5H0) in which the anomeric meth-oxyl group is axially attached this indicates the importance of the ano-... 

So-called C-linked calixsugars were prepared by Wittig reaction of the calix[4]arene tetraaldehyde 33 with galactose-6- or ribose-5-phosphorus ylids (obtained in situ from the known phosphonium iodides, Figure 5)70 followed by reduction of the double bonds and deprotection of the hydroxyl groups. Thus, the tetra- and trigalactosides 34c,d (all as P-anomers) and tetra- and tri-L-lyxosides 34 (as a mixture of a- and P-anomers) were obtained. 

A number of modified sugars have been obtained by using the aforementioned approach. For example, methyl 4-0-methyl-5,5-di-C-methyl-p-DL-lyxoside, the glycoside of the sugar component of the antibiotic novobiocin, was synthesized with high selectivity from 2-(2-furyl)propan-2-ol. Methyl 6-acetamido-6-deoxy and 6-deoxy-6-nitro-a-DL-mannopyranosides were prepared from suitably substituted 2-furylethanols. 1,4-Addition of an active methylene compounds to... 

Ishell HS, Frush HL (1940) a- and p-methyl lyxosides, mannosides, gulosides and heptosides of like configuration. J Res Natl Bur Stand 24 125-151... 

Methyl lyxoside Lyxitol Lyxonic acid Lactone Lyxuronic acid Methyl ester Deoxy... 

Reduction of the pentosid-2-ulose (8) by sodium borohydride in ethanol gave the dimer (9) as the major product, the expected lyxoside (10) being only a minor product (Scheme 4), whereas the j8-anomer of (8) gave only the j8-... 

As would be expected from the identity of the configurations of the pyranose or furanose rings, the members of each homomorphous series show marked chemical and physical similarities ), and it is often possible to predict the properties of unknown members from those of the basic type. The greatest differences, as might be anticipated, are found between the pentoses and the corresponding hexoses. It appears that enzymes which hydrolyze the hexoside members of each series also hydrolyze the glycosides of the other members of each series (4 ). Thus, the enzyme a-mannosidase of almond emulsin hydrolyzes the a-lyxosides as well as the a-mannosides. 

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