Synthesis and Biological Properties of<i>2</i>-Amino-3-fluoro-2,3-Dideoxy-D-Pentofuranosides of Natural Heterocyclic Bases

Abstract The oxidation of methyl 5–0-benzyl-3-deoxy-3-fluoro-α-D-arabi-nofuranoside (1) with DMSO/Ac2o afforded a ∼ 2:1 mixture of 2-keto derivatives with erythro and threo configuration resulting from isomerization at C3. Successive treatment of the above mixture with MeONH2, LiA1H4, and S-ethyl trifluoroacetate followed by silica gel chromatography afforded methyl 5–0-benzyl-2, 3-dideoxy-3-fluoro-2-(trifluoroacetamido)-α-D-ribofuranoside (6b) and its lyxo isomer 7b in a total yield of 25% and 5%, respectively. The arabino analogue 25 was prepared from 6b. Compounds 6b, 7b and 25 were converted to the corresponding 5–0-benzoyl derivatives 8a, 9 and 26. A series of 2′-amino-2′, 3′-dideoxy-3′-fluoro-β-D-ribo- and-α-D-lyxofuranosides of natural heterocyclic bases have been synthesized starting from 8a and 9. None of the test compounds had any antiviral activity. 3′-Fluoro-2′-amino-2′, 3′-dideoxycytidine (16) was the only compound showing inhibition of murine L1210 and human Molt/4F cell proliferation (50% effective concentration: 39–42μg/m1).