雷尼镍催化加氢合成7-氟-2H-1,4苯并噁嗪-3(4H)-酮

Preparation of 7-Fluoro-2H-1,4-benzoxazin-3(4H)-one by Catalytic Hydrogenization

研究了雷尼镍为催化剂加氢还原2-(5-氟-2-硝基苯氧基)乙酸甲酯(1)合成7-氟-2H-[1,4]苯并噁嗪-3(4H)-酮(2)的方法,使还原、合环一次完成。考察了反应温度、催化剂、氢气压力、时间、溶剂及回收的催化剂和溶剂对反应收率的影响,确定了合成工艺条件:反应温度70℃,反应时间4h,催化剂用量为原料质量的5%,氢气压力5MPa,溶剂甲醇用量为1000mL/mol1。产品的收率92.4%,含量98%,溶剂和催化剂循环使用4次,对收率无影响。产品结构经元素分析、红外光谱、核磁共振确证。

7-Fluoro-2H-1,4-benzoxazin-3 （4H）-one （2） was prepared through the reaction of hydrogenization catalyzed by Rany Nickel from methyl 2-（5-fluoro-2-nitrophenoxy） acetate （1）. The effect of temperature, catalyst, pressure of H2, reaction time, solvents and reclaim of all the solution and the catalyst were investigated. The optimum process conditions were determined as following： Reaction temperature was 70℃, time 4 h, the catalyst amount 5% comparing to 1 （w/w）, the hydrogen pressure 5 MPa and methanol 1000 mL/mol （1）. The yield was 92.4% and the purity was 98%, all the solution and the catalyst could be reclaimed for four times and had no bad effect on the yield and purity. The structure of 2 was comformed by elementary analysis, IR, and ^1H NMR.