Palladium-catalyzed cross-coupling of 8-bromo-2'-deoxyadenosine with terminal alkynes in the presence of copper(I) iodide in dimethylformamide resulted in a series of 8-(1-alkyn-1-yl)-2'-deoxyadenosines. Hydrogenation of alkynyl derivatives over 10% Pd/C under atmospheric pressure gave 8-n-alkyl analogues in nearly quantitative yields. On partial saturation of heptynyl, pentynyl, and propynyl derivatives over Lindlar catalyst, the corresponding cis-olefins were obtained along with minor amounts of trans isomers. Of the analogues tested, the following showed some activity, i.e. they were found to be active at concentrations that were at least 3-fold lower than the cytotoxic concentrations: the 8-heptynyl derivative against vaccinia virus (VV), vesicular stomatitis virus (VSV), cytomegalovirus (CMV), and respiratory syncytial virus (RSV); the 8-propyl derivative against varicella-zoster virus (VZV) and CMV; the 8-pentyl derivative against CMV; the 8-heptyl derivative against VV, CMV, RSV, and influenza A; and the 8-heptenyl derivative against VV, RSV, and influenza A. The unsubstituted 2'-deoxyadenosine did not show any antiviral effect, except against RSV. Except for 8-propyl-dA, the antivirally active dA analogues were rather inhibitory to the growth of human embryonic lung cells. The most cytotoxic was the 8-ethynyl derivative.
Enantiomerically pure (+)- and (-)-carbocyclic thymidine, (-)-carbocyclic 3'-epi-thymidine, (+)-carbocyclic 3'-deoxy-3'-azidothymidine, (+)-carbocyclic 2,3'-O-anhydrothymidine, (+)-carbocyclic 3'-O,6'-methylenethymidine, and (+)-(6'S)-carbocyclic 6'-methylthymidine were synthesized in a stereospecific manner from common chiral pools of (+)-(1R,5S)- and (-)-(1S,5R)-2-oxabicyclo[3.3.0]oct-6-en-3-one and evaluated for antiviral activity. (+)-Carbathymidine and, to a lesser extent, (+)-carbocyclic 2'-deoxyadenosine proved to be effective against HSV-1 [minimum inhibitory concentration (MIC): 0.2 and 2 micrograms/mL, respectively] and HSV-2 (MIC: 2 and 20 micrograms/mL, respectively), but virtually inactive against TK- HSV-1 (MIC: 40 and 100 micrograms/mL, respectively). (+)-Carbathymidine was also active against vaccinia virus (2 micrograms/mL). None of the compounds had a specific effect on the replication of HIV or other RNA viruses.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.