99389-26-1

913091-87-9

99389-26-1

Ethyl [(3,5-difluorophenyl)thioalkyl]thioformate (10 g, 42.68 mmol, 1.00 eq.) was dissolved in ethanol (100 mL) under nitrogen protection. Potassium hydroxide solution (9.6 g, 171.11 mmol, dissolved in 10 mL of water) was added dropwise over 5 min with stirring at room temperature. The reaction mixture was heated to reflux for 2.5 hours. After completion of the reaction, it was cooled to room temperature and the mixture was concentrated under vacuum. The residue was diluted with 200 mL of water and the resulting solution was washed with ethyl acetate (3 x 50 mL). The aqueous layer was separated and zinc powder (0.8 g) was added and the pH was adjusted to 5 with concentrated hydrochloric acid at 0-10 °C. Subsequently, the reaction solution was extracted with ethyl acetate (3 x 100 mL). The organic layers were combined, washed with brine (3 x 100 mL), dried over anhydrous sodium sulfate, and concentrated in vacuum to give the brown oily product 3,5-difluorothiophenol (5.0 g, 80% yield). detected by TLC (petroleum ether/ethyl acetate = 10:1): rf = 0.45.