Benzofuran derivs. - with powerful beta-adrenergic blocking activity

摘要

Benzofurans of general formula:- (I) R and S = lower alkyl n = 1, 2 or 3 dotted line represents an optional bond and salts of (I). (I) possess powerful beta-adrenergic activity, without sympathomimetic action. They are therefore useful in the treatment of heart conditions, e.g. arrhythmia and angina pectoris. A soln. of 2-epoxyethyl-5,6-dimethylbenzofuran (6.4 g., 0.034 ml.) and isopropylamine (4.02 g., 0.068 mole) in benzene (25 ml) was treated with BF3 etherate (10 drops), and the mixture allowed to stand for 136 hrs. at 20 deg.C. The 2-(2-isopropylamino-1-hydroxyethyl)-5,6-dimethylbenzofuran, which separates as a white solid, was filtered, and converted into the hydrochloride by reaction with HCl. Crystallisation from EtOH/ether yielded the salt (2.5 g) as colourless prisms, m.p. 175-177 deg.C.