steel bomb at 125 u00b0 140 u00b0 c for 20 hours the contents are worked up as described in example 3 the crude solid is dissolved in 15 ml of hot methanol filtered treated with 20 ml of chloroform and cooled giving 100 mg of the desired product as a cream colored solid m p 340 u00b0 342 u00b0 c dec an 89 4 g portion of magnesium turnings is covered with 613 ml of diethyl ether a small portion of bromoethane is added to start the reaction then a mixture of 100 g of 3 bromothiophene and 334 g of bromoethane in 1850 ml of diethyl ether is added dropwise at a rate to maintain gentle reflux the mixture is refluxed 40 hours cooled and poured into a mixture of dry ice and ether the mixture is stirred then allowed to stand for 2 hours and hydrolysed with 800 1000 ml of 4 n sulfuric acid the ether phase is separated and saved the aqueous phase is extracted with three 500 ml portions of ether the ether solutions are combined and extracted with two 500 ml portions of 2 n sodium hydroxide then two 400 ml portions of 1 n sodium hydroxide the alkaline extracts are combined cooled and acidified to ph 2 4 with 300 ml of cool 6 n hydrochloric acid this mixture is stirred in an ice bath for 1 5 hours and the solid is collected washed with ice water and dried giving 40 g of 3 thiophene carboxylic acid a 100 g portion of thionyl chloride is added to 34 8 g of 3 thiophene carboxylic acid.