催化加氢合成6-氨基-7-氟-2H-1,4-苯并口恶嗪-3(4H)-酮

Preparation of 6-Amino-7-fluoro-2H-1,4-benzoxazin-3(4H)-one by Catalytic Hydrogenization

6-氨基-7-氟-2H-1,4-苯并口恶嗪-3(4H)-酮(Ⅱ)是合成除草剂丙炔氟草胺的关键中间体,该文采用雷尼镍催化加氢还原7-氟-6-硝基-2H-1,4-苯并口恶嗪-3(4H)-酮(Ⅰ)高收率的制得了目标化合物Ⅱ,确定了最佳合成工艺条件:反应温度80℃,反应时间5 h,催化剂用量为原料质量的5%,氢气压力6 MPa,产品的收率95.2%,质量分数98.5%,溶剂和催化剂循环使用5次,对收率和产品质量分数无影响。产品结构经元素分析、红外光谱、核磁共振确证。

6-Amino-7-fluoro-2H-1,4-benzoxazin-3 synthesis of herbicide flumioxazin, was prepared （4H）-one （Ⅱ）, an essential intermediate for through hydrogenation of 7-fluoro-6-nitro -2H-1,4- benzoxazin-3（4H）-one （ Ⅰ ） catalyzed by Raney Ni with high yield. The optimum process conditions were reaction temperature 80℃ , reaction time 5 h, amount of catalyst 5% based on Ⅰ , and H2 pressure 6 MPa. The yield was 95.2% and weight percent of Ⅱ was 98. 5%. The solvent and the catalyst were reused for five times and showed no bad effect to the yield and weight percent of the Droduct. The structure of Ⅱ was comfirmed by elementary analysis,IR and ^1HNMR.