A method for preparing 2,5-dihalo- and 2,5,6-trihalopyridines corresponding to the formula ##SPC1## Wherein each X independently represents chloro, fluoro or bromo and R represents hydrogen, chloro, fluoro or bromo which comprises reacting a halohydrazinopyridine of one of the formulas ##SPC2## With an excess of an aqueous alkali metal hydroxide in the presence of a reaction medium from the group consisting of loweralkanols of 1 to 4 carbon atoms and loweralkylglycols of 2 to 4 carbon atoms.
一种制备2,5-二卤和2,5,6-三卤
吡啶的方法,其对应于以下公式:##
SPC1##
其中每个X独立地表示
氯、
氟或
溴,R表示氢、
氯、
氟或
溴,包括将以下任一公式的卤酰
肼吡啶:##
SPC2##
与过量的
水溶性碱
金属氢氧化物在以下反应介质的存在下反应:1至4个碳原子的低级
脂肪醇和2至4个碳原子的低级烷基
乙二醇。