Phase-transfer catalysis in the alkylation reaction of α-naphthol with epichlorohydrin

A new method for the selective alkylation of α-naphthol with epichlorohydrin using quaternary ammonium salts as phase-transfer catalysts has been developed. The reaction was investigated under the conditions of both two- and three-phase catalysis, and the reaction products were identified and characterized by chromatographic and spectrometric methods. It was possible to optimise both processes in such a manner that the main product was a compound of special interest: 1-(1-naphthoxy)-2,3-epoxypropane, an important intermediate in the production of the beta-blocker and anti-oxidant propranolol, 1-(isopropylamino)-3-α-(1-naphthoxy)-2-propanol. From the technological point of view, the use of a solid-phase catalyst is advantageous, and the catalysis by an anion exchange resin with quaternary ammonium groups was investigated in detail.