A method for preparing an alkyl 5,7-dihalo-1,4-dihydro-4-oxoquinoline-2-carboxylate ester is described herein. The method comprises cyclizing a compound of Formula III with Eaton's reagent in heated continuous flow reactor to form a compound of Formula IV wherein in Formula III and Formula IV, each X independently is a halogen atom; and each R independently is C1 to C4 alkyl. Optionally, a cosolvent such as dichloromethane can be included with the Eaton's reagent. A method of preparing a diphenylureido-dihalokynurenic acid alkyl ester of Formula VI from the compound of Formula IV also is described.
本文介绍了一种制备烷基5,7-二卤代-1,4-二氢-4-氧基
喹啉-2-
羧酸酯的方法。该方法包括将式III化合物与
伊顿试剂在加热的连续流反应器中环化,形成式IV化合物,其中在式III和式IV中,每个X独立地是卤素原子;每个R独立地是C1到C4烷基。可选地,可以在
伊顿试剂中包含
二氯甲烷等共溶剂。还描述了从式IV化合物制备式VI的二苯基
脲基-二卤代基
肟酸烷基酯的方法。