Photochemical degradation of barbituric acid derivatives. Part 8: Photolysis of sodium salts of barbiturates in solid state.

After the UV irradiation of suspensions of barbiturate sodium salts in paraffin oil the IR spectra revealed two IR absorption bands at ca. 2170 and 2250 cm-1. The effects of different conditions of the photochemical process and the addition of nucleophilic reagents after irradiation on the intensity of these bands were studied. The origin of 2170 cm-1 band was interpreted in terms of the isocyanate intermediate which is formed after the pyrimidine ring opening.