7-取代-4-喹诺酮-2-羧酸甲酯的合成

4-喹诺酮-2-羧酸甲酯衍生物的制备,一般是用苯胺衍生物与丁炔二酸二甲酯反应,生成α-(取代苯胺基)丁烯二酸二甲酯(1),继之在二苯醚中约260℃加热环合而获得。我们用间氨基苯酚与丁炔二酸二甲酯在甲醇中反应,所得黄色固体经鉴定为7-羟基-4-喹诺酮-2-羧酸甲酯(2);除去固体后的滤液在甲醇-盐酸中回流还能生成2。若用间苯二胺与丁炔二酸二甲酯反应,则生成7-氨基-4-喹诺酮-2-羧酸甲酯(3)(产率20%)和N,N′-二(1,2-双-甲氧羰基乙烯基)间苯二胺(4)(产率4.8%)。这样就不需要再在二苯醚中进行环合。2与3的易于制备,显示氨基和羟基的活化作用。2和3在室温分别与醋酐-吡啶反应,可得乙酰化物5和6.2和3在二甲基甲酰胺中与乙氧草酰氯(ethyloxalyl chloride)反应,可分别生成化合物7和8。

The synthesis of methyl 7-substituted-4-quinolone-2- carboxylate

When m-aminophenol and m-phenylenediamine were allowed to react with dimethyl acetylenedicarboxylate at room temperature, both addition and cyclization occurred, although in low yields, giving methyl 7-hydroxy-4-quinolone-2-carboxylate (2) and methyl 7-amino- 4-quinolone-2-carboxylate (3) respectively. The use of rather drastic conditions (heating in diphenyl ether) for similar cyclizations was not needed here, due to the activating influence of the amino and hydroxy functionalities in para relationship with the site of ring closure. We also prepared some acylated derivatives 5-8.