pyrazofurin pyrazofurin pyrazofurin (pyrazomycin) is a natural product found in streptomyces candidus, which is a nucleoside analogue related to ribavirin. it has antibiotic, antiviral and anti-cancer properties but was not successful in human clinical trials due to severe side effects. nevertheless, it continues to be the subject of ongoing research as a potential drug of last resort, or a template for improved synthetic derivatives. pyrazofurinclinical datatrade namespyrazofurinlegal statuslegal status us: investigational new drug identifiers iupac name 3--4-hydroxy-1h-pyrazole-5-carboxamide cas number30868-30-5pubchem cid135413551chemspider10570780unii4b15044gqzkeggd05658chebichebi:90284chemblchembl2105330chemical and physical dataformulac9h13n3o6molar mass259.22 g·mol−13d model (jsmol)interactive image smiles c(1(((o1)c2=nnc(=c2o)c(=o)n)o)o)o inchi inchi=1s/c9h13n3o6/c10-9(17)4-6(15)3(11-12-4)8-7(16)5(14)2(1-13)18-8/h2,5,7-8,13-16h,1h2,(h2,10,17)(h,11,12)/t2-,5-,7-,8+/m1/s1key:xesargfcsksfid-fllfqebcsa-n