Hydrochloric Acid → (2-Hydroxy-5-ethylphenyl)(2-thienyl)methanone

Participants

Reaction Steps

2-Hydroxy-5-ethylbenzoic acid (16.6g, 0.1 mol) and thionyl chloride (12.44g, 0.105 mol) were mixed together with light petroleum (bp 40°-60° C.) (75 ml) and pyridine (0.1 ml) and refluxed for 6 hours. The resulting 2-hydroxy-5-ethylbenzoyl chloride was stirred in carbon disulphide (120 ml), cooled in ice and treated with aluminium chloride for 1 to 2 minutes. The temperature of the mixture rose from 2° C. to 15° C. The temperature was allowed to return to about 2° C. and thiophene (8.4g, 7.91 ml. 0.1 mol) in carbon disulphide (25 ml) was added at a rate such that the temperature of the mixture did not rise above about 3° C. The mixture was then stirred at room temperature overnight, stirred and refluxed for 31/2 hours, cooled, poured into ice and concentrated hydrochloric acid, and extracted with ether. The ether fraction was washed firstly with a saturated solution of sodium bicarbonate and secondly with a saturated solution of sodium chloride, was dried (over Na2SO4), filtered and evaporated to yield an oil which was distilled to give the pure title product (0.67g), bp 118°-122° C./0.07 mm, nD19 1.6280.

Provenance & Evidence