1,3-Di(4-pyridyl)propane 17252-51-6 4,4'-(Propane-1,3-diyl)dipyridine 4,4'-Trimethylenedipyridine EINECS 241-284-8 NSC 42785 Pyridine, 4,4'-(1,3-propanediyl)bis- Pyridine, 4,4'-trimethylenedi- (8CI)