Nitrogen-14 nuclear quadrupole resonance study of several hydroxypyrimidines

Abstract

Nitrogen-14 nuclear quadrupole resonance (NQR) spectra of several hydroxypyrimidines of biological and pharmacological importance are reported and analyzed in the framework of the semiempirical Townes and Dailey theory. Included among the compounds are thymine, uracil, uridine, barbituric acid, orotic acid, and cyanuric acid. The results obtained suggest that in all cases the molecules in their ground state exist predominantly in the dilactam tautomeric form. Significant differences have been observed in the NQR spectra of the two nitrogens in barbituric acid which cannot be accounted for by the differences in the hydrogen bond lengths alone.