The facile and general synthesis of 2-substituted 6-alkylidenehydrazino-or 6- arylmethylidenehydrazino-7H-purines and 3-and/or 5-substituted 9H-1, 2, 4-triazolo [3, 4-i] purines, which were obtained by oxidative cyclisation of the corresponding 6-aldehyde hydrazones of 7H-purine, as a new class of potential xanthine oxidase inhibitors are reported. Their inhibitory activities against bovine milk xanthine oxidase in vitro were also ...