1 3 7-trimethyl-2 3 6 7-tetrahydro-1h-purine-2 6-dione July 8, 2019 16 32 64 128 1 3 7-trimethyl-3 4 5 7-tetrahydro-1h-purine-2 6-dione 1 3 7-trimethyl-3 7-dihydro-1h-purine-2 6-dione
