SYNTHESIS AND ANTIVIRAL ACTIVITY OF 1-BETA-D-ARABINOFURANOSYLURACILS AND URIDINES CONTAINING 5-[2-BROMO-2-CHLORO (OR BROMO)-1-HYDROXY (OR METHOXY) ETHYL] SUBSTITUENTS

D-Arabinofuranosyl-5-(-2,2-dibromo-1-hydroxyethyl) uracil (4) and abin ofuranosyl-5-(2-bromo-2-chloro-1-hydroxyethyl) uracil (5) were synthes ized by the regiospecific addition of HOX (X = Br or Cl) to the vinyl substituent of (E)-5-(2-bromovinyl)arabinouridine (2). A related react ion of 2 and its uridine analog (3) with bromine in methanol afforded the 5-(2,2-dibromo-1-methoxyethyl) derivatives (6 and 7). Of the newly synthesized compounds, 4 and 5 showed activity in vitro against HSV-1 . The most active compound (4, ED50 = 7.5 mug/mL) was 25 times less ac tive than acyclovir (ED50 = 0.3 mug/mL).