Rapid and selective reduction of amide group by borane-amine complexes in acyl protected nucleosides
Borane-amine complexes provide an unusually fast and selective reduction of a deoxynucleoside N-acyl group to a corresponding N-alkyl group. Three different nucleosides (dG, dA, and dC) each having one of three N-protecting groups (benzoyl, isobutyryl, or acetyl) were used to prepare N-alkylated nucleosides in good yields under mild conditions. Deoxyribose O-acyl protecting groups remain intact at the conditions of N-acyl group reduction.
Sergueeva, Zinaida A.,Sergueev, Dmitri S.,Shaw, Barbara Ramsay
p. 275 - 282
(2007/10/03)
Transformations of thiopyrimidine and thiopurine nucleosides following oxidation with dimethyldioxirane
A general and convenient method for the synthesis of several pyrimidine and purine nucleosides by selective oxidation of thionucleosides with dimethyldioxirane is reported. Thioketo moieties in the C-4 position of the pyrimidine ring, and in the C-6, and C-8 positions of the purine ring are the domain of oxidative nucleophilic substitution. Thioketo moieties in the C-2 position of both purine and pyrimidine rings are the domain of desulfurization or formation of disulfides.