申请人:Laboratoire Roger Bellon
公开号:US04125720A1
公开(公告)日:1978-11-14
Process for the preparation of a 4-chloro-5-alkoxycarbonyl-2-methoxy-pyrimidine of the formula: ##STR1## IN WHICH R.sub.1 is a lower alkyl radical with 1 to 4 carbon atoms, which comprises the following stages: A) condensation of a salt of O-methylisourea and an inorganic or organic acid, with an alkyl alkoxymethylenemalonate ##STR2## in an aqueous medium and in the presence of an excess of an alkali metal hydroxide, to form the corresponding salt of the 5-alkoxycarbonyl-4-hydroxy-2-methoxy-pyrimidine, and neutralization of the said salt by the addition of an inorganic or organic acid, in order to liberate this 5-alkoxycarbonyl-4-hydroxy-2-methoxy-pyrimidine, and ##STR3## B) bringing the latter compound, suspended in dimethylformamide, into contact with thionyl chloride, at room temperature, in order to form the corresponding 4-chloro-5-alkoxycarbonyl-2-methoxy-pyrimidine: ##STR4##
制备4-氯-5-烷氧羰基-2-甲氧基嘧啶的过程如下,该嘧啶的化学式为:##STR1##
其中R1是1至4个碳原子的低碳基,包括以下步骤:A)在水介质中和过量的碱金属氢氧化物的存在下,将O-甲基异脲盐和无机或有机酸的盐与烷基烷氧甲基丙二酸酯##STR2##缩合,形成相应的5-烷氧羰基-4-羟基-2-甲氧基嘧啶的盐,并通过加入无机或有机酸来中和该盐,以释放此5-烷氧羰基-4-羟基-2-甲氧基嘧啶,并##STR3##B)将后一化合物悬浮在二甲基甲酰胺中,在室温下与氯化硫酰反应,以形成相应的4-氯-5-烷氧羰基-2-甲氧基嘧啶:##STR4##