Theacrine2309-49-133 % similar 1-Methyl-1H-imidazole-4,5-dicarboxylic acid19485-38-232 % similar 3-Methyl-5-beta-D-ribofuranosyl-2,4(1H,3H)-pyrimidinedione81691-06-732 % similar Doxofylline69975-86-631 % similar 2-Methoxy-1,7,9-trimethylpurine-6,8-dione51168-26-431 % similar