Beschreibung:
Two new products were isolated from uracil irradiated with ultraviolet light in frozen aqueous solution. As judged by mass, nuclear magnetic resonance, and ultraviolet and infrared spectra, one is a photopolymer, U$_{3}$, and the structure of the other is probably 6-4′-[pyrimidin-2′-one]-uracil. Formations of these products between pyrimidine bases are apparently common photoreactions, and may be important to the study of the photochemistry and photobiology of nucleic acids.