- Stereoselective Preparation of C-Aryl Glycosides via Visible-Light-Induced Nickel-Catalyzed Reductive Cross-Coupling of Glycosyl Chlorides and Aryl Bromides
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A nickel-catalyzed cross-coupling reaction of glycosyl chlorides with aryl bromides has been developed. The reaction proceeds smoothly under visible-light irradiation and features the use of bench-stable glycosyl chlorides, allowing the highly stereoselective synthesis of C-aryl glycosides. (Figure presented.).
- Mou, Ze-Dong,Wang, Jia-Xi,Zhang, Xia,Niu, Dawen
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supporting information
p. 3025 - 3029
(2021/05/27)
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- Reaction of 1,2-trans-glycosyl acetates with phosphorus pentachloride: New efficient approach to 1,2-trans-glycosyl chlorides
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Reaction of phosphorus pentachloride with 1,2-trans-glycosyl esters is described. The reaction mechanism presumably involves formation of a tetrachlorophosphonium ion as one of the key reactive intermediates, which can be induced either by Lewis acids or by using acetonitrile as the reaction solvent. Two novel, efficient methods for the synthesis of the thermodynamically unstable glycosyl chlorides were developed based on this reaction.
- Ibatullin, Farid M.,Selivanov, Stanislav I.
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p. 9577 - 9580
(2007/10/03)
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- Preparation of glycosyltriazenes
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O-Unprotected glycosyltriazenes are prepared for the first time by coupling of 1-anthraquinone-1-diazonium hydrogensulfate with β-glycopyranosylamines to afford 1-(anthraquinone-1-yl)-3-(β-glycopyranosyl)triazenes 3a-h. Acetylation of compounds 3 furnished the O-acetates 4a-g. The stability of triazenes 3 results from fixation of the NH proton in an intramolecular hydrogen bond to one of the anthraquinone carbonyl oxgen atoms. Treatment of triazenes 4 with tert-butyl hypochlorite afforded acetoglycosyl chlorides 6 and 1-azidoanthraquinone 7. With acetic acid the triazene 4a formed tetra-O-acetyl-D-xylopyranose 9 together with 1-aminoanthraquinone 10. WIiley-VCH Verlag GmbH, 2000.
- Weng, Min,Jochims, Johannes C.
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p. 530 - 536
(2007/10/03)
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- REACTION OF GLYCOSYL HALIDES WITH BENZYL GRIGNARD REAGENTS: UNEXPECTED o-TOLYL ALKYLATION OF TETRA-O-ACETYLGLUCOPYRANOSYL BROMIDE AND DIRECT SYNTHESIS OF (β-GLYCOSYL)PHENYLMETHANES
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The synthesis of (β-glycosyl)phenylmethanes by Grignard alkylation of glycosyl halides is investigated.Reaction of tetra-O-acetylglucopyranosyl bromide with benzylmagnesium chloride gave a good yield of a 3:1 mixture of 2-(β-D-glucopyranosyl)toluene and (β-glucosyl)phenylmethane.The requirement for an equatorial 2-acetoxy group and 6-acetoxymethyl group for the formation of the unexpected o-tolyl rearrangement product is explored by using xylosyl, mannosyl, and 2-deoxyglucosyl halides as substrates for the alkylation.Synthesis of (β-glucosyl)phenylmethane by alkylation of 2,3,4,6-tetra-O-benzylglucosyl bromide with benzylmagnesium chloride is also presented.
- Panigot, Michael J.,Curley, Robert W.
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p. 293 - 302
(2007/10/02)
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- PREPARATION OF 4-RETINAMIDOPHENYL- AND 4-RETINAMIDOBENZYL-C-GLYCOSYL AND C-GLUCURONOSYL ANALOGUES OF THE GLUCURONIDE OF 4-HYDROXYPHENYLRETINAMIDE AS POTENTIAL STABLE CANCER CHEMOPREVENTIVE AGENTS
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Glucuronide metabolites of retinoic acid and its analogues have been suggested to be active cancer chemopreventive analogues of the parent molecules.However, these metabolites are susceptible to β-glucuronidase and acid-catalyzed cleavage and it is not clear whether these carbohydrate conjugates must be hydrolyzed back to the parent molecule to show activity.Thus, the multistep syntheses of stable C-glycosyl and C-glucuronosyl analogues of the known glucuronide metabolite of the breast cancer chemopreventive agent 4-hydroxyphenylretinamide (4-HPR) are outlined.The chemical and enzymatic stability of these compounds has been evaluated relative to the glucuronide of 4-HPR.
- Panigot, M. J.,Humphries, K. A.,Curley, R. W.
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p. 303 - 322
(2007/10/02)
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