The invention relates to a process for the preparation of dimethyl-1,4-dihydro-2,6-dimethyl-4-(2'-nitro-phenyl)-pyridine-3,5-dicarbo xylate of the Formula I ##STR1## which comprises a) reacting a compound of the general Formula II ##STR2## (wherein n is 1 or 3; if n is 1, then R stands for a group of the Formula (a) ##STR3## and if n is 3, then R represents hydrogen) with methyl acetoacetate of the Formula III CH.sub.3 --CO--CH.sub.2 --COOCH.sub.3 (III) and optionally with an amino compound of the general Formula IV ##STR4## (wherein Z is a group of the Formula (c), ##STR5## k is 1 and both symbols p are 0; or Z stands for a C.sub.1-5 straight or branched chain alkanoyloxy group or a carbonate, hydrocarbonate or hydroxy anion, k is 1 and both symbols p are 1; or k is 0, one of both symbols p is 0 and the other is 1) in an inert solvent; or b) reacting 2-nitro-benzaldehyde and methyl acetoacetate of the Formula III and aqueous ammonium hydroxide in the presence of an inert solvent in one step, at a temperature of 101.degree.-120.degree. C., under a pressure of 2.0-6.0 bar.
                            本发明涉及一种制备式I的二甲基-1,4-二氢-2,6-二甲基-4-(2'-
硝基苯基)-
吡啶-
3,5-二羧酸二甲酯的方法,其中式I为:##STR1## 该方法包括:a) 在惰性溶剂中反应式II的化合物##STR2## (其中n为1或3; 如果n为1,则R代表式(a)的基团##STR3## 如果n为3,则R代表氢)与式III的
乙酰乙酸甲酯反应,可选地与式IV的
氨基化合物##STR4## (其中Z为式(c)的基团##STR5## k为1,两个符号p均为0; 或Z代表C.sub.1-5直链或支链烷酰氧基或
碳酸酯、氢
碳酸酯或羟基阴离子,k为1,两个符号p均为1; 或k为0,其中一个符号p为0,另一个符号为1);或b) 在惰性溶剂存在下,在101℃-120℃的温度下,2-硝基
苯甲醛和式III的
乙酰乙酸甲酯以及
水合
氨在一步反应中反应,在2.0-6.0巴的压力下。