2'-C-branched ribonucleosides. 2. Synthesis of 2'-C-beta-trifluoromethyl pyrimidine ribonucleosides.
[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 a powerful reaction intermediate for the synthesis of ribonucleosides. The reaction of silylated pyrimidines with (5) in the presence of HgO/HgBr2 affords exclusively the beta-anomers (6-8). Deprotection of (6-8) with ammonia in methanol yields the 2'-C-beta-trifluoromethyl nucleosides (9-11).
Li
N S
NS
Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biology, The University of Chicago, 5841 S. Maryland Avenue, MC 1028, Chicago, Illinois 60637, USA.
Tang
X Q
XQ
Piccirilli
J A
JA
D006031:Glycosylation; D008968:Molecular Conformation; D015394:Molecular Structure; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry; D012263:Ribonucleosides / Q000138:chemical synthesis* / Q000737:chemistry
D011743:Pyrimidines; D012263:Ribonucleosides