Selective Removal of the 2‘- and 3‘-O-Acyl Groups from 2‘,3‘,5‘-Tri-O-acylribonucleoside Derivatives with Lithium Trifluoroethoxide1
摘要:
Selective cleavage of O2' and O3' ester groups from ribonucleoside derivatives has been accomplished with Dowex 1 x 2 (CF3CH2O-) in 2,2,2-trifluoroethanol (TFE) or lithium trifluoroethoxide/TFE. Deacylations with Li+ -OCH2CF3/TFE proceed at ambient temperature (or with mild heating) to give the 5'-O-acyl derivatives in superior yields and higher purity than prior approaches for selective O2' and O3' ester deprotection.
Hydrothermal Deamidation of 4-N-Acylcytosine Nucleoside Derivatives: Efficient Synthesis of Uracil Nucleoside Esters
摘要:
[GRAPHICS]N,O-Peracylated cytidine and 2'-deoxycytidine derivatives in superheated water/DME solutions (oil bath at 125 degrees C) undergo hydrolytic deamidation (and/or N-deacylation). Acylated starting materials derived from arylcarboxylic acids give the corresponding uridine esters cleanly, and such derivatives crystallize selectively from the cooled reaction mixtures in high yields.