By condensation of N-methyl-1-naphthylmethylamine (I) with 4-(tert-butyl)benzyl bromide (II) by means of Na2CO3 in DMF, followed by acidification with HCl in ethanol.
By condensation of 1-(chloromethyl)naphthalene (I) with N-(4-tert-butylbenzyl)-N-methylamine (II) by means of sodium carbonate in hot DMF.