3-Methyl-1H-purine-2,6(3H,7H)-dione2,6-Dihydroxy-3-Methylpurine3-甲基黄嘌呤2,6-Dihydroxy-3-methylpurine3-METHYLXANTHINE2,6-二羟基-3-甲基嘌呤3-Methylxanthine3 MX3-methyl-3,7(9)-dihydro-purine-2,6-dioneN(1)-demethyltheophylline3-methyl-3,9-dihydro-2H,6H-purine-2,6-dione3-Methylxanthine3-methylxanthine2-oxo-3-methylhypoxanthine3,9-dihydro-3-methyl-1H-purine-2,6-dione3,7-dihydro-3-methyl-1H-purine-2,6-dione3-methyl-7H-xanthine3-methyl-9H-xanthine