5-fluorocytosine is prepared by reacting 2,5-difluoro-4-chloro-pyrimidine with a proton acid in the presence of water to yield 2-hydroxy-4-chloro-5-fluoropyrimidine and reacting the 2-hydroxy-4-chloro-5-fluoropyrimidine with ammonia to yield 5-fluoro-cytosine.
[EN] BENZO BICYCLIC COMPOUND, AND PREPARATION METHOD AND APPLICATION THEREOF<br/>[FR] COMPOSÉ BENZO BICYCLIQUE, SON PROCÉDÉ DE PRÉPARATION ET SON APPLICATION<br/>[ZH] 苯并双环类化合物及其制备方法和应用