Hydrochloric Acid → HCID 21428786, compound

Participants

Reaction Steps

A stirring mixture of 154.8 g of 2-bromobenzoic acid, 107.1 g of thionyl chloride and 0.2 ml of dimethylformamide is heated on a steam bath for 45 minutes and then any excess thionyl chloride is distilled off under reduced pressure leaving the crude acid chloride. A mixture of the acid chloride and 60 g of thiophene in 255 g of carbon disulfide is added dropwise to a suspension at 15° C of 100 g of aluminum chloride and 300 g of carbon disulfide. After total addition the mixture is stirred at ambient temperature for 3 hours and then allowed to stand for 16 hours. The stirring mixture is now successively refluxed on a steam bath for 3.5 hours, cooled to ambient temperature and poured over 1 l. of ice followed by dilution with 0.5 l. of water. The biphasic mixture is strained through glass wool to remove any precipitate and then permitted to separate. The aqueous phase is extracted with three 600 ml portions of ether. The ether extracts are combined with the carbon disulfide phase and this mixture is washed with two 500 ml portions of an aqueous 5% sodium carbonate solution followed by washing with two 500 ml portions of water. The organic solution is dried, filtered and then concentrated under reduced pressure leaving a dark oil. The oil is distilled leaving as the main fraction, b.p. 139°-145° C, a green colored oil of 2-(2-bromobenzoyl)thiophene. A solution of 15.0 g of 2-(2-bromobenzoyl)thiophene in 15 ml of absolute ethanol is carefully added with stirring and cooling to a mixture of 2.3 g of sodium borohydride in 40 ml of absolute ethanol. After total addition 15 ml of absolute ethanol is added. The reaction mixture is stirred for 16 hours at ambient temperature and then 50 ml of acetone is added with stirring and the mixture is permitted to stand for 24 hours at ambient temperature. The mixture is poured into 500 ml of water and the resulting mixture acidified with a 5% hydrochloric acid solution causing the mixture to become cloudy. The cloudy mixture is extracted with three 125 ml portions of chloroform which are combined and washed with ten 200 ml portions of water. The chloroform solution is dried and filtered and the chloroform evaporated off leaving α-(2-bromophenyl)-2-thiophenemethanol as an oil.

Provenance & Evidence