申请人:Ciba-Geigy Corporation
公开号:US04748244A1
公开(公告)日:1988-05-31
The invention relates to a process for the preparation of pyridine-2,3-dicarboxylic acid derivatives of formula ##STR1## which process comprises reacting a hydrazone of formula II ##STR2## with a maleic acid derivative of formula III ##STR3## to give a 1-amino-1,4-dihydropyridine-2,3-dicarboxylic acid derivative of formula IV ##STR4## and subsequently removing R.sub.9 R.sub.10 NH. In the above formulae, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.9, R.sub.10 and X are as defined in claim 1. The pyridine-2,3-dicarboxylic acid derivatives of formula I are intermediates for the preparation of herbicidal compounds.
本发明涉及一种制备式为##STR1##的吡啶-2,3-二羧酸衍生物的过程,该过程包括将式II的肼酮##STR2##与式III的马来酸衍生物##STR3##反应,从而得到式IV的1-氨基-1,4-二氢吡啶-2,3-二羧酸衍生物##STR4##,随后去除R.sub.9 R.sub.10 NH。在上述式中,R.sub.1、R.sub.2、R.sub.3、R.sub.4、R.sub.9、R.sub.10和X如权利要求1所定义。式I的吡啶-2,3-二羧酸衍生物是除草剂化合物的中间体。