反应详情

2.4 g. of 5-Amino-6-methylamino-4-chloro-2-methylpyridine-3-carboxylic acid ethyl ester (0.01 mol.) and 10 ml. of orthoformic acid triethyl ester are refluxed for 12 hours. After the excess ortho ester has been removed, the residue is recrystallized from ethyl acetate to obtain 7-chloro-3,5-dimethyl-3H-imidazo[4,5-b]pyridine-6-carboxylic acid ethyl ester, m.p. 56°-58° . Yield 2.2 g. (88%).

1. customAfter the excess ortho ester has been removed
2. customthe residue is recrystallized from ethyl acetate