Spectrophotometric studies op nucleic acid derivatives and related compounds as a function of pH: I. Pyrimidines

Abstract

1. 1. The ultraviolet absorption spectra of a number of nucleic acid derivaties (pyrimidines) and related compounds have been measured at various pH values. 2. 2. The variation of the spectra with pH is shown in all cases to be explicable on the basis of ionic dissociation. 3. 3. The apparent dissociation constants have been calculated from the spectra. 4. 4. The structure of uracil (and thymine) is shown to be in the diketo form in neutral solution. Two ionic equilibria are demonstrated in alkaline solution and the order of dissociation is shown to proceed through the 2- and 4-hydroxyl groups respectively. 5. 5. The spectra and structures of other pyrimidine derivatives are discussed.