PROCESS FOR THE PREPARATION OF 3-(3-CHLORO-1H-PYRAZOL-1-YL)PYRIDINE

摘要

This disclosure relates to the field of preparation of 3-(3-chloro-IH-pyrazol-1-yl)pyridine and intermediates therefrom. These intermediates are useful in the preparation of certain (3-halo-l-(pyridin-3-yl)-1 H-pyrazol-4-yl)amides and carbamates and their use as pesticides. Provided herein is an alternative process for preparing 3-(3-chloro-1Hpyrazol-l-yl)pyridine (5b) by cyclizing 3-hydrazino pyridine dihydrochloride with an alkyl methacrylate to provide 4-methyl-1-(pyridin-3-yl)pyrazolidin-3-one (1), by chlorinating (1) to provide 3-(3-chloro-4-methyl-4,5-dihydro-IH-pyrazol-1-yl)pyridine (2), by oxidizing (2) to provide 3-(3-chloro-4-methyl-1H-pyrazol-1-yl) pyridine (3), by further oxidizing (3) to provide 3-chloro-1 -(pyridin-3-yl)-1 H-pyrazole-4-carboxylic acid (4), and by decarboxylating (4) to provide 3-(3-chloro-1H-pyrazol-l-yl)pyridine (5b).