Synthesis and antitumor activity of ribavirin imidates. A new facile synthesis of ribavirin amidine (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride).

Methyl 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboximidate (4) and ethyl 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamidate (6) were synthesized and tested for antitumor and antiviral activity. A new facile synthesis of 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride (5), starting with imidate 4, was also developed. The imidates 4 and 6 differed greatly in solubility and dosing requirements. Even so, both compounds exhibited significant activity in vivo against murine leukemia L1210. Nontoxic dosing with 4 also significantly diminished Friend leukemia induced splenomegaly. In contrast, neither imidate was active in vitro.