The condensation of acetone (VIII) with 2-methoxybenzaldehyde (IX) by means of NaOH gives 2-methoxybenzalacetone (X), which is reduced with H2 over Raney-Ni in ethanol to yield 4-(2-methoxyphenyl)-2-butanone (XI). The Grignard reaction of (XI) with methylmagnesium iodide in ether affords 1,1-dimethyl-3-(2-methoxyphenyl) propanol (XII), which by reaction with NaCN by means of H2SO4 in acetic acid affords N-[1,1-dimethyl-3-(2-methoxyphenyl)propyl]formamide (XIII). Finally, this compound is hydrolyzed with refluxing 5N NaOH to give (II).
The bromination of 4-benzyloxyacetophenone (VI) with Br2 in dioxane gives 4-benzyloxyphenacyl bromide (VII), which by reduction with NaBH4 in dioxane and epoxidation with NaOH water is converted into (I). The condensation of 4-benzyloxystyrene oxide (I) with 1,1-dimethyl-3-(2-methoxyphenyl)propylamine (II) in refluxing isopropanol gives 1-(4-benzyloxyphenyl)-2-[1,1-dimethyl-3-(2-methoxyphenyl)propylamino]ethanol (III), which is debenzylated by reduction with H2 over Pd/C in ethanol, and treated with HCl.
The oxidation of (VI) with SeO2 in hot dioxane-water gives 4-benzyloxyphenylglyoxal (IV). The condensation with (II) in refluxing ethanol, gives 4-benzyloxy-alpha-[1,1-dimethyl-3-(2-methoxyphenyl)propylimino]acetophenone (V), which is then reduced with NaBH4 in ethanol to afford (III), which is debenzylated by reduction with H2 over Pd/C in ethanol, and treated with HCl.