反应详情

WO 02/36587 describes a process for preparing a 5-alkoxy-4-halogenoalkoxy-2-nitrobenzoic acid compound from a 3-alkoxy-4-hydroxybenzoic acid compound. For example, ethyl vanillate (i.e., ethyl 4-hydroxy-3-methoxybenzoate) is reacted with 3-bromo-1-chloropropane in an aqueous potassium carbonate solution in the presence of N-butyl-ammonium bromide to produce ethyl 4-(3-chloropropoxy)-3-methoxybenzoate, and the ethyl 4-(3-chloropropoxy)-3-methoxybenzoate is reacted with 70% nitric acid in a mixture of dichloromethane and acetic acid, to give ethyl 4-chloropropoxy-3-methoxy-2-nitrobenzoate in 82% yield (based on the amount of ethyl vanillate).