| 摘要 |
PURPOSE:To obtain a 5-fluorocytosine hydrofluoride as a crystal, by dissolving cytosine hydrofluoride in acidic ammonium fluoride used as a reaction medium, fluorinating the salt with fluorine gas at normal temperature, heat-treating the reaction product and adding an alcohol to the system. CONSTITUTION:Cytosine hydrofluoride is dissolved in an acidic ammonium fluoride of formula NH4F.nHF (n is preferably 4-20) and fluorinated with fluorine gas at 0-40 deg.C, preferably 15-30 deg.C. The obtained intermediate is heated in the reaction medium at 40-80 deg.C, preferably 60-65 deg.C to form a double bond between 5- and 6-positions and obtain a 5-fluorocytosine salt. Crystal of 5- fluorocytosine hydrofluoride can be almost quantitatively separated by mixing the reaction medium with an alcohol. The separated crystal is deacidified with e.g. ammonia water to obtain the objective 5-fluorocytosine. The reaction easily proceeds under mild condition. The product is useful as an antibacterial agent.
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