2-Methyl-5,6-cyclopentapyrimidine 2-Methyl-5,6-trimethylenepyrimidine 2-Methyl-6,7-dihydro-5H-cyclopentapyrimidine 36274-29-0 5H-Cyclopentapyrimidine, 6,7-dihydro-2-methyl- 6,7-Dihydro-2-methyl-5H-cyclopentapyrimidine CCRIS 6513 MeCpp