| 摘要 |
PURPOSE:To produce high-purity 6-amino-7-fluoro-2H-1,4--benzoxazin-3(4H)-one useful as an intermediate of agricultural and medical drugs, especially herbicides in high yield by using ready operations. CONSTITUTION:While supplying hydrogen gas under the atmospheric or applied pressure, generally the atmospheric pressure-about 30 atm into a solution containing (a) a catalyst for catalytic reduction such as palladium dioxide, palladium carbon or Raney nickel and (b) an acid catalyst such as hydrochloric acid, sulfuric acid, acetic acid or p-toluenesulfonic acid, a fluorodinitrobenzene derivative of formula I (R is lower alkyl), as necessary, in a state dissolved in a solvent, is added thereto and reacted therewith at room temperature-200 deg.C, generally 30-130 deg.C. Thereby, 6-amino-7-fluoro-2H-1,4-benzoxazin-3 (4H)-one can be obtained with industrial advantage. In addition, the reaction temperature is readily controlled by controlling the rate of supply of the compound represented by formula I. |
