摘要:
Results of PM3 semiempirical calculation revealed that energy and hydrogen bonds geometry of 1-methyl-5-fluoro-uracil and -cytosine base-pairs with 9-methyladenine and -guanine respectively are virtually the same as for the natural bases. Analysis of proton coupling constants proved that the sugar puckering of 5-fluorouridine and 5-fluorocytidine is analogous to non-modified ribonucleosides. 5-Fluorocytidine was regioselectively introduced to oligoribonucleotides, prepared using 2'-O-tert-dimethylsilyl protection, via post-synthetic quantitative ammonolysis of 4-O-methyl-5-fluorouridine derived precursor.