| 摘要 |
An improved process for preparing (E)-2-(2-chloromethylphenyl)-2-alkoximinoacetic esters of Formula (I), in which R is a radical inert to the reaction, n is 0 to 4 and R1 and R5 may each independently be C1-C8-alkyl radicals, which comprises reacting a compound of Formula (II), in which n, R and R1 are each as defined above with o-methylhydroxylammonium hydrochloride (CH3ONH2-HCI) in a solvent mixture at a pH of from 0 to 7, which is established by adding an inorganic base, to give an isomer mixture of Formula (III), in which n, R, R1 and R5 are each as defined above, then extracting with cyclohexane, then isomerizing the isomer mixture by introducing gaseous hydrochloric acid, neutralizing the reaction mixture and crystallizing the compound of the formula (I) after adding a cosolvent. |
