A general method for N-glycosylation of nucleobases promoted by (p-Tol)<sub>2</sub>SO/Tf<sub>2</sub>O with thioglycoside as donor
作者:Guang-jian Liu、Xiao-tai Zhang、Guo-wen Xing
DOI:10.1039/c5cc03617h
日期:——
35 nucleosides were synthesized by coupling thioglycosides with pyrimidines and purines under the preactivation of (p-Tol)2SO/Tf2O in high yields and with β-stereoselectivities.
Reaction of primary or secondary 1,3-diols with dibenzoxazol-2-yl disulfide and tributylphosphine or triphenylphosphine selectively gave 2-(3-hydroxyalkylthio)benzoxazoles which, on treatment with KH, were converted into the corresponding thietanes. 2,2-Dibenzylthietane-1-oxide reacted with silylated purines and pyrimidines in the presence of TMSOTf and ZnI2 to give the corresponding thietane nucleosides in 17-69% yields.
2‘-<i>C</i>-Branched Ribonucleosides. 2. Synthesis of 2‘-<i>C</i>-<i>β</i>-Trifluoromethyl Pyrimidine Ribonucleosides<sup>1</sup>
作者:Nan-Sheng Li、Xiao-Qing Tang、Joseph A. Piccirilli
DOI:10.1021/ol0155687
日期:2001.4.1
[structure: see text]. The first synthesis of 2'-C-beta-trifluoromethyl pyrimidine ribonucleosides is described. 1,2,3,5-Tetra-O-benzoyl-2-C-beta-trifluoromethyl-alpha-D-ribofuranose (3) is prepared from 1,3,5-tri-O-benzoyl-alpha-D-ribofuranose (1) in three steps and converted to 3,5-di-O-benzoyl-2-C-beta-trifluoromethyl-alpha-D-1-ribofuranosyl bromide (5). The 1-bromo derivative (5) is found to be
The design of processes which combine tandem and sequentialreactions allows the transformation of readily available precursors into high-profit products. This strategy is illustrated by the one-pot synthesis of acyclic nucleosides, which are potential antiviral compounds, from readily available carbohydrates. The reaction conditions are mild, compatible with most functional groups. Depending on the