Fluoronucleosides, Isothiocyanato C-Nucleosides, and Thioureylene Di-C-nucleosides via Cyclic Sulfates
摘要:
Cyclic sulfates of N- and C-nucleosides (D-ribo and D-erythro configurations, respectively) are used to prepare T-fluoro and 3'-azido D-xylo N-nucleosides and L-threo C-nucleosides. The reduction of the 3'-azido C-nucleosides (furan, imidazoline-2-thione, and pyrrole derivatives) gives T-amino C-nucleosides, which, by reaction with thiocarbonyldiimidazole, are transformed into T-isothiocyanato C-nucleosides. Reaction of the 3'-amino with the T-isothiocyanato C-nucleosides gives thioureylene di-C-nucleosides, a type of nucleotide analogue with a nonionic bridge isosteric of the phosphate group.
1,3-Diketones and β-oxo esters undergo smooth coupling with d-glucosamine in the presence of 25 mol% CeCl3˙7H2O in water at 80 ˚C to furnish C-pyrrolyl glycosides in good to high yields. The reaction of cyclic diketones such as dimedone with d-glucosamine affords the corresponding 2-(3,4-dihydroxytetrahydrofuran-2-yl)-6,7-dihydro-1H-indol-4(5H)-one derivatives. These dihydroxy derivatives are directly
InCl3-catalyzed synthesis of C-pyrrolyl glycosides via tandem condensation of aminosugars and 1,3-dicarbonyl compounds in water
作者:Boyu Li、Gang Wang、Zhongjun Li、Xiangbao Meng
DOI:10.1016/j.tetlet.2011.05.083
日期:2011.7
Various C-pyrrolyl glycosides were obtained through tandem condensation of aminosugars (d-glucosamine and d-galactosamine) and 1,3-dicarbonylcompounds under green conditions in moderate to good yields. The reactions were carried out in the presence of 10 mol % InCl3 in water at 50 °C. A reaction mechanism through carbocation intermediates was proposed.