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Intramolecular glycosidation

Hydroxyethyl-D-glucose (Intramolecular glycosidation) a-Furanoside and the anomeric pyrano-sides were obtained No kinetic information available p-fura-noside likely to be highly unstable because of trans-in%ion of a five- and a six-membered ring 23)... [Pg.38]

An interesting problem in stereoisomerism is found in the aldol reactions of the achiral aldehydes which are obtained by ozonolysis of the homoallylic alcohols 174. After stereospecific conversion by the FruA [230], the products can be readily induced to form an intramolecular glycoside 175 by acidic (R=OH) or alkaline treatment (R=C1), under which conditions the two equatorial ring hydroxyl groups completely direct the stereogenic acetal formation [234]. The corresponding RhuA catalyzed reactions deliver the enantiomeric... [Pg.176]

M. Bols and H. C. Hansen, Long range intramolecular glycosidation, Chem. Lett., (1994) 1049-1052. [Pg.177]

Bols, M, Stereocontrolled synthesis of a-glucosides by intramolecular glycosidation, J. Chem. Soc. Chem. Commun., 913-914, 1992. [Pg.237]

Bols, M, Intramolecular glycosidation stereocontrolled synthesis of a-glucosides from a 2-0-alkoxysilyl thioglucoside, Acta Chem. Scand., 47, 829-834, 1993. [Pg.237]

Bols, M, Efficient stereocontrolled glycosidation of secondary sugar hydroxyls by silicon tethered intramolecular glycosidation, Tetrahedron, 49, 10049-10060, 1993. [Pg.237]

Gomez, A M, Valverde, S, Fraser-Reid, B, A route to unsaturated spiroketals from phenylthiohex-2-enopyranosides via sequential alkylation, allylic rearrangement, and intramolecular glycosidation,... [Pg.361]

Fig. (4). Caryophyllose (24), its isomeric methyl and intramolecular glycosides (25 and 26) and some of its derivatives and degradation products (27-30). Fig. (4). Caryophyllose (24), its isomeric methyl and intramolecular glycosides (25 and 26) and some of its derivatives and degradation products (27-30).
Scheme 10-93 Leaving group-based intramolecular glycoside bond formation is an attractive route to stereoselective glycosylation. Scheme 10-93 Leaving group-based intramolecular glycoside bond formation is an attractive route to stereoselective glycosylation.
Deprotection of the l°-hydroxyl initiates formation of the intramolecular glycoside (1,6-anhydrosugar), resulting in simultaneous protection of the anomeric centre and the 6-OH. [Pg.59]

Scheme 3 outlines a synthesis of 2 -0-methyl-6,3 -ethanouridine 24, in which intramolecular glycosidation is a key step. The product 24 was incorporated into antisense oligonucleotides. ... [Pg.266]

Condensation of a hemiacetal hydroxyl with another hydroxyl group in the same molecule produces an anhydro sugar (glycosan) which can be considered as an intramolecular glycoside. The most common glycosans may be classified, by their skeletal structures, as 1,2-anhydro- and 1,6-anhydro-pyranoses, and 1,6-anhydrofuranoses. The ether anhydro derivatives are considered in Chapter VII. [Pg.220]

The 1-deoxypsicofuranosyl nucleoside 14 has been converted to the 1,3,4-trideoxy-derivative by stepwise deoxygenations, and 2, 5 -dideoxy-5-fluorouridine (45) has been made by trans-glycosylation of 5 -deoxythymidine using thymidine phosphorylase. The anhydro-thionucleoside 46 was prepared by intramolecular glycosidation (see Vol. 8, p. 149 for a similar case), and on treatment with Raney nickel gave the 2, 5 -dideoxynucleoside 47. 2... [Pg.231]

Deoxy-6,2 -methano-pyrimidine nucleosides are accessible by a sequence including Peterson olefination and intramolecular glycosidation, as outlined in Scheme 3 (for an earlier route, see Vol. 19, p. 198-9). Intermediate (19) can be transformed into the uridine, cytidine and 4-thiouridine systems. 8... [Pg.227]

A computational study on the mechanism and kinetics of the pyrolysis of 2-nitrophenyl azide is in agreement with a one-step concerted mechanism (63)-(65) and turns down various intermediates which have been discussed in the literature. The OT-xylylene moiety has been applied as a rigid spacer in intramolecular glycoside bond formation This application is highly face-selective and efficient in generating 14- and 15-membered macrocycles. [Pg.354]

An intramolecular glycosidation was used as a key step in the route to some 2 -deoxy-6,3 -methano-cyclopyrimidine nucleosides... [Pg.205]

Two problems are usually encountered in the synthesis of a glycosidic bond— unreactive hydroxyl groups and lack of diastereoselectivity (i.e. formation of a and P epimers). To overcome these problems in the last decade chemists have explored a new approach—intramolecular glycosidation reactions. [Pg.449]


See other pages where Intramolecular glycosidation is mentioned: [Pg.41]    [Pg.353]    [Pg.294]    [Pg.122]    [Pg.176]    [Pg.50]    [Pg.35]    [Pg.535]    [Pg.535]    [Pg.154]    [Pg.274]    [Pg.737]    [Pg.738]    [Pg.1303]    [Pg.24]    [Pg.600]    [Pg.154]    [Pg.271]    [Pg.290]    [Pg.81]    [Pg.263]    [Pg.33]    [Pg.189]    [Pg.35]    [Pg.118]    [Pg.449]   
See also in sourсe #XX -- [ Pg.303 ]




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Glycosides intramolecular

Intramolecular General Acid Catalysis of Glycoside Hydrolysis

Intramolecular Glycosidations

Intramolecular glycosidation reactions

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