反应详情

In step c of Scheme 2, methyl 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylate (6d) is saponified in the presence of an inorganic base, preferably metal hydroxides or their hydrates such as lithium hydroxide hydrate (LiOH.H2O) in water and a polar solvent such as dioxane at temperatures from about 0° C. to about 30° C. to yield 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylic acid (6e). Alternatively, this process can also be accomplished by hydrolysis by exposing methyl 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylate (6d) to a concentrated acid such as hydrochloric acid in water at temperatures from about 30° C. to about 100° C.