The present invention relates to a process for the preparation of compounds of formula (1), in which R1, R2 and R3 independently of one another are hydrogen, halogen , trifluoromethyl of or C1-C4alkoxy, wherein a compound of formula (2), in which R1, R2 and R3 are as defined in formula (1), is reacted with methlyamine in the presence of a non-alcoholic solvent and, if desired, in the presence of a sulfonic acid catalyst to give the compound of formula (2) and, if desired, is subject to purification by recrystallization.
本发明涉及一种制备式(1)化合物的方法,其中R1、R2和R3彼此独立地是氢、卤素、三
氟甲基或C1-C4烷氧基,其中在非醇溶剂存在下,将式(2)化合物(其中R1、R2和R3如式(1)中定义)与
甲胺反应,并在必要时在
磺酸催化剂存在下,得到式(2)化合物,并在必要时通过再结晶进行纯化。