Process for the preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridine
US9809570B2 · kind B2 · utility
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13Claims
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Key dates
| Filing date | Oct 27, 2016 |
| Grant date | Nov 7, 2017 |
| Priority date | — |
| Expiry date | Oct 27, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D401/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.