Synthesis of Tubercidin, 6-Chlorotubercidin and Related Nucleosides

Tubercidin (7-deazaadenosine, 1a) and several 6-chlorotuber-cidin derivatives were synthesized including 4-amino-6-chloro-7-β-D-ribofuranosylpyrrolo[2,3-d]pyrimidine-3′,5′-cycyclic phosphate 9. Isolation of a side product found in the glycosylation step of the reaction sequence proved to be the N-1 ribosyl-attached isomer as shown by X-ray diffraction analysis. All derivatives were tested for in vitro antiviral and antitumor activity.