A series of 3'-deoxy-3'-fluoro- and 2'-azido-2',3'-dideoxy-3'-fluoro-D-ribofuranosides of natural heterocyclic bases have been synthesized with the use of universal carbohydrate precursors, viz., 1-O-acetyl-2,5-di-O-benzoyl-3-deoxy-3-fluoro-D-ribofuranose and methyl 2-azido-5-O-benzoyl-2,3-dideoxy-3-fluoro-beta-D-ribofuranoside, respectively. The cytostatic and antiviral activity of the compounds was evaluated against a variety of tumor cell lines and DNA/RNA viruses, respectively. As the most active compound, from both a cytostatic and antiviral activity viewpoint, emerged 3'-deoxy-3'-fluoroadenosine. It inhibited the proliferation of some tumor cell lines (i.e. murine leukemia L1210 and human T-lymphocyte MT-4) at a concentration of 0.2-2 micrograms/mL, and proved inhibitory to the replication of positive-stranded RNA viruses (i.e. polio, Coxsackie, Sindbis, Semliki forest), double-stranded RNA viruses (i.e. reo), and some DNA viruses (i.e. vaccinia) at a concentration of 1-4 micrograms/mL, which is well below the cytotoxicity threshold (40 micrograms/mL).

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Synthesis of 9-(beta-D-arabinofuranosyl)guanine (ara-G) from 1-(beta-D-arabinofuranosyl)cytosine (ara-C) and guanine, guanosine or 2'-deoxyguanosine (dG) by glutaraldehyde-treated Escherichia coli BM-11 cells is described. It is shown that the concentration of phosphate ions, molar ratio of substrates and pH of the reaction medium are factors affecting product yield. Under optimum conditions ara-G was produced in the reaction mixture in a yield of 63%-65% based on dG as the best source of guanine base. The yield of isolated ara-G was 48%-53%.

It is shown that dNTP(3'F) are terminators of DNA synthesis and may serve as very effective tools for DNA sequencing with E.coli DNA polymerase I and AMV reverse transcriptase. The dNTP(3'F) are found to be chain terminator substrates for calf thymus terminal deoxyribonucleotidyl transferase but not for calf thymus DNA polymerase α. The optimal dNTP(3'F) concentration for DNA sequencing by DNA polymerase I is found to be an order of magnitude lower than that of ddNTPs. dNTP(3'F) produce a more clear sequence pattern than do ddNTPs.

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