Reduction of N-Boc-3-nitrobenzylamine (I) by catalytic hydrogenation over Pd/C yields aniline (II). This is then condensed with S-methyl-2-thiophenethiocarboximide (III) to furnish amidine (IV). Subsequent acidic Boc group cleavage yields amine (V).

3,5-Diisopropyl-4-hydroxybenzaldehyde (VI) is esterified with acetyl chloride, producing acetate (VII). Subsequent Wittig condensation of aldehyde (VII) with carboethoxymethylene triphenylphosphorane leads to the cinnamyl derivative (VIII), which is further hydrogenated to the arylpropionic ester (IX). After saponification of ester (IX) with LiOH, the resultant carboxylic acid (X) is coupled to amine (V), producing amide (XI). Finally, amide reduction with borane in THF gives rise to the target amine.