Spectra of C2ν deuterium substituted pyrimidines

Abstract

Pyrimidine, pyrimidine-2- d, pyrimidine-2,5- d 2, pyrimidine-4,6- d 2, pyrimidine-2,4,6- d 3 and pyrimidine- d 4 have been prepared. Isotopic purity and label specificity were established by proton magnetic resonance and mass spectroscopy. The principal fragmentation pathway in the mass spectrometer ion beam is shown to involve a splitting of HCN from the pyrimidine ring produced by loss of the 4 position carbon. Liquid phase Raman and liquid and vapor phase i.r. spectra are reported. Vibrational assignments consistent with frequency sum rule and product rule criteria are given for most of the 144 fundamentals involved. The two A 2 fundamentals of pyrimidine-4,6- d 2, pyrimidine-2,4,6- d 3 and pyrimidine- d 4, and one of the A 2 fundamentals of pyrimidine, pyrimidine-2- d and pyrimidine-2,5- d 2 are identified. Some assignments of earlier authors are altered in order to achieve reasonable frequency sum and product rule agreement.