Condensation of glycidate (I) with 3,4,5-trimethoxybenzyl amine (II) in hot EtOH affords the hydroxy amino ester (III). Subsequent ester hydrolysis in (III) employing LiOH yields carboxylic acid (IV). This is coupled to N-2-hydroxy-4-methoxybenzyl-L-valinamide (V) by means of TPTU to furnish (VI). Then, removal of the N-Boc protecting group of (VI) with HCl in dioxane provides amine (VII).

Coupling of N-Boc-L-tert-leucine (VIII) to amine (VII) in the presence of TPTU gives rise to amide (IX). After acidic Boc group cleavage in (IX), the resultant amine (X) is finally acylated by 1-naphthylacetic acid (XI) to furnish the title compound.