2-Hydroxypyrimidine hydrochloride

Chloropyrimidine has been prepared by a similar procedure by Howard.2 The compound has also been prepared from 2-hydroxypyrimidine hydrochloride by treatment with a mixture of phosphorus pentachloride and phosphorus oxychloride 3 or by treatment with phosphorus oxychloride alone.4... 

Pyrimidinyl halides are not only precursors for Pd-catalyzed reactions, but also important pharmaceuticals in their own right. One of the most frequently employed approaches for halopyrimidine synthesis is direct halogenation. When pyrimidinium hydrochloride and 2-aminopyrimidine were treated with bromine, 5-bromopyrimidine and 2-amino-5-bromopyrimidine were obtained, respectively, via an addition-elimination process instead of an aromatic electrophilic substitution [4, 5], Analogously, 2-chloro-5-bromopyrimidine (1) was generated from direct halogenation of 2-hydroxypyrimidine [6], Treating 1 with HI then gave to 2-iodo-5-bromopyrimidine (2). In the preparation of 5-bromo-4,6-dimethoxypyrimidine (4), N-bromosuccinimide was found to be superior to bromine for the bromination of 4,6-dimethoxypyrimidine (3) [7]. 

Ethanolic sodium ethoxide is employed also to effect condensation of guanidine (taken as the hydrochloride) with ethyl cyanoacetate to produce 2,4-diamino-6-hydroxypyrimidine. With urea as reactant in place of guanidine, the product is... 

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