PARTITION PROPERTY OF 5-NITROTHIOPYRIMIDINE NUCLEOSIDE

5-Nitrouracil and 5-nitrouridine derivatives which C-2 and C-4 ore-gro ups of the pyrimidine base were replaced by thio groups were synthesiz ed. The lipophilicities of thiopyrimidine bases were enhanced signific antly as indicated by P-values. Oxygen-sulfur exchange leading to 2-th iouracil (2) and 2,4-dithiouracil (3) were associated with 1.4- and 2. 6-fold increase in P-value relative to that of uracil (1). The P-value s of 5-nitro-2-thiouracil (5) and 5-nitro-2,4-dithiouracil (6) were in creased 13.2- and 79.8-fold relative to that of 5-nitrouracil (4). Mos t of the 5-nitrothiopyrimidine bases and their nucleosides were found to be moderately active against Staphylococcus aureus and Escherichia coli except 5-nitrouracil (4).