6-Hydroxy-8-mercaptopurine 6305-94-8 6H-Purin-6-one, 1,7,8,9-tetrahydro-8-thioxo- 8-Mercaptohypoxanthine 8-Thiohypoxanthine Hypoxanthine, 8-mercapto- NSC22713 SQ 21,978 SQ 21978