Methanol → 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylic acid

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Reaction Steps

A mixture of 0.30 g of ethyl 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylate, 5 ml of methanol and 5 ml of a 2N aqueous sodium hydroxide solution was heated to reflux for 3 hours. After the reaction mixture was allowed to cool, water was poured and the aqueous layer was washed with methyl t-butyl ether two times. The aqueous layer was adjusted to around pH 3 by an addition of 2N hydrochloric acid, and then extracted with methyl t-butyl ether three times. The combined organic layer was washed with an aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 0.24 g of 1-(3-chloro-2-pyridinyl)-3-methyl-1H-pyrazole-5-carboxylic acid of the formula:

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