Potassium Hydroxide → HCID 23312203, compound

Participants

Reaction Steps

11.5 g of 4-(5-chloro-2-benzofuranyl)-1-piperidinecarboxlic acid ethyl ester is dissolved in 75 ml of ethylene glycol. After the addition of 50 ml of a 50% aqueous potassium hydroxide solution, the formed cloudy solution is heated, with vigorous stirring, for 15 hours at 160°; the reaction solution is thereupon cooled to 20°, and extracted twice with 500 ml of ethyl acetate each time. The organic phases are washed five times with 1 liter of water each time, dried over sodium sulphate, filtered, and concentrated by evaporation. The residue is dissolved in 300 ml of a 10% solution of methanesulphonic acid in water, and the acid solution extracted with ether. The aqueous solution is then adjusted by addition of 10% sodium hydroxide solution to have a pH value of 12, and extracted with 1 liter of chloroform. The chloroform solution is dried with sodium sulphate, filtered, and concentrated by evaporation to obtain crude 4-(5-chloro-2-benzofuranyl)-piperidine. The free base melts at 77°-78° after recrystallisation from hexane. The hydrochloride is prepared with hydrogen chloride in ethyl acetate, and recrystallised from ethyl acetate, whereupon it melts at 252°-254°.

Provenance & Evidence