Surprisingly, and in contrast to the behavior of 2-methylthiazolo [5, 4-dlpyrimidine-5, 7-diol, neither thiazolo [4, 5-d] pyrimidine-5, 7-dioI nor its% methyl analog react with phosphorus oxychloride or phosphorus pentachloride under usual conditions.(A conceivable parallel has been observed in the inert behavior of 2, 4-dihydroxy-G-aminopyrimidine toward phosphorus oxychloride in contrast to the ready reaction of 4, 6-dihydroxy-2- ...