1,3-Trimethylene thymine cyclic tetramer 1,3-Ttct 1,5,9,13,17,21,25,29-Octaazapentacyclo(27.3.1.15,9.113,17.121,25)hexatriaconta-7,14,23,30-tetraene-6,16,22,32,33,34,35,36-octone, 7,15,23,31-tetramethyl- 68675-73-0