1-ethyl-1,4-dihydro-4-oxo-7-<1-(2-pyridinyl)-1H-pyrazol-4-yl>-1,8-naphthyridine-3-carboxylic acid, methyl ester 、 alkaline earth salt of/the/ methylsulfuric acid 反应 2.0h,
以80%的产率得到1-ethyl-1,4-dihydro-4-oxo-7-<1-(2-pyridinyl)-1H-pyrazol-4-yl>-1,8-naphthyridine-3-carboxylic acid