1,2-Dichloroethane → Ethyl 5-chloro-1-(pyridin-2-YL)-1H-pyrazole-4-carboxylate

関与物質

反応手順

To a solution of ethyl 5-amino-1-(pyridin-2-yl)-1H-pyrazole-4-carboxylate (200 mg, 0.861 mmol) and copper (II) chloride (116 mg, 0.861 mmol) in 1,2-dichloroethane (8 mL) was added tert-butyl nitrite (0.154 mL, 1.292 mmol). The reaction mixture was stirred at rt for 16 hrs. The reaction mixture was diluted with 30 mL of dichloromethane and was washed with 10 mL of 2M NH4OH solution, 10 mL of brine and dried over Na2SO4. Filtration and concentration yielded a crude product which was purified on silica gel column eluting with hexanes/EtOAc to afford ethyl 5-chloro-1-(pyridin-2-yl)-1H-pyrazole-4-carboxylate.

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