Carboxylic acids of formula (1): ##STR1## wherein R.sup.2 and R.sup.3 are independently hydrogen or C.sub.1 -C.sub.3 alkyl, and Q is optionally substituted phenyl, can be easily converted by ring closing into pyridazin-3-one derivatives of formula (7): ##STR2## The carboxylic acids of formula (1) can be produced by reacting hydrazone compounds of formula (5): ##STR3## wherein R.sup.3 and Q are as defined above, with malonic acid derivatives of formula (6): R.sup.2 CH(COOH).sub.2 wherein R.sup.2 is as defined above in the presence of a base.
公式(1)的
羧酸:##STR1## 其中R.sup.2和R.sup.3分别是氢或C.sub.1-C.sub.3烷基,而Q是可选的取代苯基,可以通过环闭合轻松转化为公式(7)的
吡啶并[3,4-d]
嘧啶衍
生物:##STR2## 公式(1)的
羧酸可以通过将公式(5)的腙化合物反应生成:##STR3## 其中R.sup.3和Q如上所定义,与公式(6)的
丙二酸衍
生物反应生成:R.sup.2 CH(COOH).sub.2 其中R.sup.2如上所定义,在碱存在下。