2-Halo derivatives of 3'-acetamido-3'-deoxyadenosine

9-(3-Acetamido-2,5-di-O-acetyl-3-deoxy-beta-D-ribofuranosyl)-2,6-dichloropurine (VI) prepared by the mercuric cyanide catalyzed reaction of 3-acetamido-2,5-di-O-acetyl-3-deoxy-D-ribofuranosyl chloride (III) with 2,6-dichloropurine, was converted by standard reactions to 3'-acetamido-2-chloro-3'-deoxyadenosine (VII) and 3'-acetamido-3'-deoxy-2-fluoroadenosine (X). The 2-chloroadenine nucleoside VII was not cytotoxic, but the 2-fluoroadenine nucleoside X was moderately so, and its cytotoxicity to a subline of H.Ep.-2 cells resistant to 2-fluoroadenine indicates that its activity is due to the intact nucleoside.