| 摘要 |
PURPOSE:To obtain the title substance in high purity and in high yield by reacting a pheoxyacetaldehyde dialkylacetal with bromine and then treating the reaction product with an alkali metal hydroxide or alcoholate dissolved in an alcohol. CONSTITUTION:1mol compound shown by formula I (R1 and R2 are H or lower alkyl; R3 is 1-6C alkyl) is reacted with 1.0-1.3mol bromine at 0-10 deg.C for 1-5 hours by dripping bromine. As the reaction mixture from which the reaction solvent is removed is maintained at <=30 deg.C, an alkali metal hydroxide or alcoholate dissolved in an alcohol shown by the formula R3OH is dripped into the reaction mixture and the solvent is removed to give a compound shown by formula II. The amount of the alkali metal hydroxide (e.g., NaOH or KOH) is 0.5-2.0mol based on 1mol bromine. In the above-mentioned method, o-isomer and dibromo compound are hardly prepared as by-products. The compound shown by formula II is useful as a synthetic intermediate for acaricides. |
