SYNTHESIS AND BIOLOGICAL-ACTIVITY OF 4'-THIONUCLEOSIDES OF 2-CHLOROADENINE

,3,5-Tetra-O-acetyl-4-thio-D-ribofuranose,prepared from 2,3,5-tri-O-be nzyl-D-ribofuranose in four steps, was converted to the corresponding 2-chloroadenine nucleoside (8), which was deoxygenated to obtain 2-chl oro-2'-deoxy-4'-thioadenosine (12). This is the first report of a 2'-d eoxy-4'-thioribonucleoside of a purine rather than a pyrimidine. These novel nucleosides (8 and 12) were cytotoxic to several human tumor ce ll lines in culture.