ruvic acid. The formation of the xanthopterin derivative is favored both in 2 N sulfuric acid and in dilute acetic acid; the isoxanthopterin derivative is formed in poor yield only during the condensation in: acetic acid. The two isomers are separable by their different solubilities in hot 2 N hydrochloric acid and are distinguishable by their ultraviolet absorption spectra. A new pyrimidine, 2-mercapto-4, 5-diaminopyrimidine, was synthesized and used as an ...
