4,6-Dichloro-5-methylnicotinic acid 、
7-(4-Bromo-2-chlorophenylamino)-8-methylimidazo[1,2-a]pyridine-6-carboxylic acid 、
叠氮化钠 、 4-(4-Bromo-2-chloro-phenylamino)-6-chloro-5-methylnicotinic acid methyl ester 以which results in a separable mixture of the desired methyl ester, 6-azido-4-(4-bromo-2-chlorophenylamino)-5-methylnicotinic acid methyl ester的产率得到