The antifungal agent (E)-N-methyl-N-(1-naphthylmethyl)-6,6-dimethyl-hept-2-ene-4-ynyl-1-amine of formula (I) and acid addition salts thereof are prepared by reacting a chloro-compound of formula (IIIb) with a secondary amine of formula (II) in an aliphatic ketone-type solvent in the presence of a base and optionally iodide salt catalyst, and subsequently treating the resulting reaction mixture directly with aqueous hydrochloric acid to precipitate the hydrochloride of the compound of formula (I). The precipitate is separated, and the base of formula (I) can be liberated from the hydrochloride and can be converted into other pharmaceutically acceptable acid addition salts.