Process for the preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridine
AssigneeDow AgroSciences LLC
InventorsQiang Yang, Beth Lorsbach, David E. Podhorez
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Abstract
3-(3-chloro-1H-pyrazol-1-yl)pyridine is prepared by cyclizing 3-hydrazinopyridine-•dihydrochloride with a dialkyl maleate to provide an alkyl 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylate, by chlorinating to provide an alkyl 3-chloro-1-(pyridin-3-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate, by oxidizing to provide an alkyl 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylate, by converting the ester to the carboxylic acid by hydrolysis to provide 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-5-carboxylic acid hydrochloride, and by removing the carboxylic acid by a decarboxylation reaction.
Claims13
A process for preparing an alkyl 3-chloro-1-(pyridin-3-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate (10b)
- comprising
- treating a alkyl 5-oxo-2-(pyridin-3-yl)pyrazolidine-3-carboxylate (10a)
- with a chlorinating reagent in an inert organic solvent at a temperature of about 25° C. to about 100° C., wherein R is (C1-C4) alkyl.
Dependencies are inferred from the claim text.