THE SYNTHESIS OF SOME 5-SUBSTITUTED AND 5,6-DISUBSTITUTED 2'-DEOXYURIDINES

5-Alkyl(cycloalkyl)-2'-deoxyuridines VIa-VIf were synthesised in high yields by condensation of the corresponding silylated bases with 2-deoxy-3,5-di-O-p-toluoyl-D-erythro-pentosyl chloride in chloroform and subsequent deblocking with sodium methoxide in methanol. The beta-configuration, anti-glycosidic conformation and C2'-endo (S) sugar pucker of all of these compounds has been established from their H-1 NMR, C-13 NMR, UV and mass spectra. Under the same conditions, the condensation of silylated 5,6-trimethyleneuracil, resulted in 1:2/alpha:beta anomeric mixture (overall yield 71%) and syn-conformation of the 5,6-trimethylene-2'-deoxyuridine [Xg]. The results of the condensation of the silylated 5,6-dimethyluracil are discussed as well. No significant antiviral activity has been found in testing the synthesised compounds against a range of herpes, influenza and HIV-1 viruses.