申请人:Bayer Aktiengesellschaft
公开号:US04990622A1
公开(公告)日:1991-02-05
A process for the preparation of 2-chloro-5-chloromethylpyridine of the formula (I) ##STR1## which is used as an intermediate for the preparation of insecticides, the process comprising (a) reacting in a first step nicotinic acid of the formula (II) ##STR2## with phosphorus pentachloride, if appropriate in the presence of thionyl chloride and if appropriate in the presence of a diluent, (b) reacting in a second step the resulting 3-trichloromethylpyridine from the first step, of the formula III, ##STR3## with an alkali metal alkoxide of the formual (IV) R--O--M (IV) in which R represents alkyl and M represents an alkali metal cation, if appropriate in the presence of a diluent, (c) reacting in a third step the resulting pyridine ether acetal from the second step, of the formula (V), ##STR4## in which R has the abovementioned meaning with water, if appropriate in the presence of a catalyst acid, (d) hydrogenating in a fourth step the resulting pyridine aldehyde from the third step, of the formula (VI), ##STR5## in which R has the abovementioned meaning with molecular hydrogen in the presence of a hydrogenation catalyst and, if appropriate, in the presence of a diluent, and, finally, (e) reacting in a fifth step the resulting pyridylmethanol from the fourth step of the formula (VII), ##STR6## in which R has the abovementioned meaning.
一种制备用于杀虫剂制备的2-氯-5-氯甲基吡啶(式I)的过程,包括:(a)在第一步中,将烟酸(式II)与五氯化磷反应,必要时在亚砜氯的存在下,必要时在稀释剂的存在下;(b)在第二步中,将第一步中得到的3-三氯甲基吡啶(式III)与碱金属烷氧化物(式IV)反应,其中R代表烷基,M代表碱金属阳离子,必要时在稀释剂的存在下;(c)在第三步中,将第二步中得到的吡啶醚缩醛(式V)与水反应,必要时在催化酸的存在下;(d)在第四步中,将第三步中得到的吡啶醛(式VI)与分子氢在氢化催化剂的存在下反应,必要时在稀释剂的存在下;最后,(e)在第五步中,将第四步中得到的吡啶甲醇(式VII)反应。