Potassium Hydroxide → 2-(2,4-Dichlorophenylsulfanyl)-propionic acid

Participants

Reaction Steps

A mixture of 11.78 g of 2,4-dichlorothiophenol and 12.0 g of potassium hydroxide in 50 ml of acetone was stirred and heated to reflux. 11.77 g of ethyl 2-bromopropionate were added gradually and the mixture was heated under reflux for 22 hours. After cooling to room temperature, the mixture was filtered and the filtrate was evaporated to dryness. The residue was taken up in 400 ml of diethyl ether and the solution was washed with 400 ml of water and 400 ml of 10% sodium carbonate solution dried over anhydrous sodium sulfate and evaporated to dryness. A solution of the residue in a mixture of 30 ml of ethanol and 17 ml of 10% potassium hydroxide solution was heated under reflux for 21 hours. The solution was evaporated to dryness and the residue was dissolved in 50 ml of water. The resulting solution was washed twice with 50 ml of diethyl ether each time and then acidified with concentrated hydrochloric acid and extracted twice with 150 ml of ethyl acetate each time. The combined organic extracts were washed twice with 200 ml of water each time, dried over anhydrous sodium sulfate and evaporated to dryness. The residue was recrystallized from diethyl ether to give 4.08 g of 2(RS)-(2,4-dichlorophenyl-thio)propionic acid in the form of a yellow solid of melting point 95°-98° C.

Provenance & Evidence