Catalysis in the alkylation reaction of 1-naphthol with epichlorohydrin

Two new and improved procedures were developed for the synthesis of 1-(1-naphthyloxy)-2,3-epoxypropane as an important intermediate in the production of the beta-blocker and antioxidant 1-[(1-methylethyl)amino]-3-(1-naphthyloxy)- 2-propanol (propranolol). Both base homogeneous and heterogeneous PTC catalysis were employed. High yields and remarkable selectivity were achieved. The improved purity is particularly important, in view of the quality requirements for propranolol hydrochloride as an active pharmaceutical ingredient.