The reduction of 4-(p-methoxyphenyl)-3-buten-2-one (II) with hydrogen over Raney-Ni in ethyl acetate gives the corresponding butanone (III), which is then condensed with homoveratrylamine (IV) in the same solvent to give the imine (V). This product, without isolation, is reduced again with hydrogen over Pd/C to yield 3,4-dimethoxy-N-[3-(4-hydroxyphenyl)-1-methylpropyl]-beta-phenylethylamine (I), which by demethylation with HBr in refluxing acetic acid.
The Friedel-Crafts reaction of anisole (VI) with crotonyl chloride (VII) by means of AlCl3 in carbon disulfide gives p-methoxyphenyl propenyl ketone (VIII), which is then condensed with homoveratrylamine (IV) in toluene yielding 3-(3,4-dimethoxyphenylethylamino)-1-(4-methoxyphenyl)butan-1-one (IX). Finally, this ketone is reduced with hydrogen over Pd/C in ethanol to yield 3,4-dimethoxy-N-[3-(4-hydroxyphenyl)-1-methylpropyl]-beta-phenylethylamine (I), which by demethylation with HBr in refluxing acetic acid.
The reaction of 4-(4-methoxyphenyl)-2-butylamine (X) with 3,4-dimethoxyphenylacetic acid (XI) at 200 C gives 2-(3,4-dimethoxyphenyl)-N-(4-methoxyphenyl-1-methyl-n-propyl)acetamide (XII), which is then reduced with borane in THF to yield 3,4-dimethoxy-N-[3-(4-hydroxyphenyl)-1-methylpropyl]-beta-phenylethylamine (I), which by demethylation with HBr in refluxing acetic acid.