Knowledge Bank

Pyrimidine, pyrimidine-2-d, pyrimidine-2,5-$d2$, pyrimidine-4,6-$d2$, pyrimidine-2,4,6-$d3$, and pyrimidine-$d4$ were prepared from the corresponding chloropyrimidines by catalytic dehalogenation with deuterium gas. Isotopic contaminants were estimated by mass spectrometry and labelling specificity confirmed by nuclear magnetic resonance spectra. The Raman spectrum in the liquid phase and the infrared spectrum in both the liquid and vapor phases are reported for the above $C2v$ pyrimidine species. Based on the state of polarization of the Raman lines, the absence of $A2$ vibrations in the infrared spectrum and the band envelopes in the vapor phase infrared spectrum an assignment is given which satisfies the Tellex-Redlich product rule and several instances of the frequency sum rule.