Facile synthesis of 5′-deoxy- and 2′,5′-dideoxy-6-thiopurine nucleosides by nucleoside phosphorylases

5'-Deoxy-6-thioguanosine, 2',5'-dideoxy-6-thioguanosine, 5'-deoxy-6-mercaptopurine riboside and 2',5'-dideoxy-6-mercaptopurine riboside were synthesized enzymatically from thiopurine bases and corresponding ribosyl donors using nucleoside phosphorylase. This is the first report of trans-5'-deoxyribosylation to thiopurine bases by nucleoside phosphorylase. 5'-Deoxy-6-thioguanosine selectively blocked the growth of v-ras-transformed human bronchial epithelial cells. In addition, the in vitro antitumor cytotoxicity data for 5'-deoxy- and 2',5'-dideoxy-6-thiopurine nucleosides were comparable to those for the corresponding thiopurine bases. (C) 1998 Elsevier Science Ltd. All rights reserved.