3-(Acetylsulfanyl)propanoyl chloride → (+/-)-1-[3-(Acetylthio)-1-oxopropyl]-3-(2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid

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Reaction Steps

(±)-3-(2-Pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid (3.82 g) is dissolved in 100 ml of water containing 2.12 g of sodium bicarbonate at 10° C. 3-(Acetylthio)propionyl chloride (3.9 g) in 15 ml of ether and 20% sodium carbonate solution are added simultaneously; the pH is maintained between 7.5 and 8.5. The reaction mixture is then stirred at room temperature for 2 hours and extracted with ether (discarded). The aqueous layer is acidified with acetic acid and extracted with ethyl acetate three times. The solvent is dried over anhydrous magnesium sulfate and concentrated in vacuo, yielding the title compound.

Provenance & Evidence