Ethanol → HCID 86692432, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of (5-bromo-3-chloropyridin-2-yl)hydrazine (14.78 g) in water (15 ml) and concentrated hydrochloric acid (15 ml), was added an ethanol solution (30 ml) of ethyl 2-(ethoxymethylene)acetoacetate (30 ml), prepared according to a method described in J. Chem. Soc. Perkin trans. I, 1875 (1988), and the mixture was stirred at 100° C. for 1.5 hours. The reaction solution was cooled to room temperature, water (100 ml) was added and extracted with ethyl acetate three times. The organic layer was dried over anhydrous sodium sulfate and concentrated in vacuo. n-Hexane (150 ml) was added, and ethyl acetate was further added little by little at 80° C. to completely dissolve the residue. The solution was cooled to room temperature and the precipitated solid was filtered. The filtrate was concentrated and a similar handling was repeated four times to give 1-(5-bromo-3-chloropyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (15.93 g) as a pale yellow solid.

Provenance & Evidence