paraxanthine1,7-Dimethylxanthine1,7-Dimethyl-1H-purine-2,6-dione1 ,7-Dimethylxanthine2,6-Dihydroxy-1,7-dimethylpurineParaxanthine1,7-Dimethylxanthine3,7-Dihydro-1,7-dimethyl-1H-purine-2,6-dionep-Xanthine3,7-Dihydro-1,7-dimethyl-1H-purine-2,6-dioneParaxanthine1,7-dimethylxanthine1,7-Dimethylxanthine1,7-dimethylxanthine