- Glycosylation of smoke-derived volatile phenols in grapes as a consequence of grapevine exposure to bushfire smoke
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The presence of glycosides of smoke-derived volatile phenols in smoke-affected grapes and the resulting wines of Chardonnay and Cabernet Sauvignon was investigated with the aid of highperformance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). All volatile phenols studied (phenol, p-, m-, and o-cresols, methylguaiacol, syringol, and methylsyringol) could be detected as glycosylated metabolites in smoke-affected grapes in a similar fashion to that previously reported for guaiacol. These phenolic glycosides were found in smoke-affected grapes and wines at significantly elevated levels compared to those in non-smoked control grapes and wines. The extraction of these glycosides from grapes into wine was estimated to be 78% for Chardonnay and 67% for Cabernet Sauvignon. After acid hydrolysis, a large proportion of these phenolic glycosides in grapes (50%) and wine (92%) disappeared but the concentrations of volatile phenols determined by gas chromatography-mass spectrometry (GC-MS) were lower than expected. In the case of wine, the majority of the glycosides of phenol, cresols, guaiacol, and methylguaiacol were decomposed upon acid hydrolysis without releasing their respective aglycones, while syringol and methylsyringol were more effectively released. 2010 American Chemical Society.
- Hayasaka, Yoji,Baldock, Gayle A.,Parker, Mango,Pardon, Kevin H.,Black, Cory A.,Herderich, Markus J.,Jeffery, David W.
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experimental part
p. 10989 - 10998
(2011/06/23)
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- Synthesis of Vancomycin from the Aglycon
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Vancomycin-resistant bacterial strains pose a serious threat to human health. Efforts to overcome vancomycin resistance by modifying the natural product have shown that the carbohydrates help modulate biological activity. To explore the mechanisms by which the carbohydrates function, it would be useful to have access to vancomycin derivatives containing different disaccharides. We now describe the synthesis of vancomycin from a readily available protected aglycon. This chemistry lays the groundwork for wide-ranging investigations of the roles of the carbohydrates in the biological activity of vancomycin. Moreover, in developing methods to glycosylate vancomcyin, we have extended the utility of the sulfoxide glycosylation reaction considerably by making it possible to use unhindered esters as neighboring groups. The chemistry we describe may also have implications for how to improve some other glycosylation methods.
- Thompson, Christopher,Ge, Min,Kahne, Daniel
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p. 1237 - 1244
(2007/10/03)
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- Highly efficient β-glucosylation of the acidic hydroxyl groups, phenol and carboxylic acid, with an peracetylated glucosyl fluoride using a combination of BF3·Et2O and DTBMP as a promoter
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A combination of BF3·Et2O and DTBMP was established to be an efficient promoter of β-glucosylation of both phenols and carboxylic acids with a peracetylated glucosyl fluoride (2). This new method achieved remarkably high yields and β
- Oyama, Kin-Ichi,Kondo, Tadao
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p. 1627 - 1629
(2007/10/03)
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- Novel Synthesis of Aryl 2,3,4,6-Tetra-O-acetyl-D-glucopyranosides
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The glucosidation of phenols with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl fluoride in the presence of BF3*OEt2 to give, predominantly, α-anomers has been studied.In the presence of an amine base, 1,1,3,3-tetramethylguanidine, however, enhanced β-selectivity was achieved.The former reaction provides a novel and useful synthesis of aryl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside whilst the latter is effective for the glycosidation of relatively hindered phenols.
- Yamaguchi, Masahiko,Horiguchi, Akira,Fukuda, Akira,Minami, Toru
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p. 1079 - 1082
(2007/10/02)
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