Nitrophenoxyacetate (III) (prepared from 2-nitrophenol (I) and tert-butyl bromoacetate), was reduced with H2 in the presence of Pd/C to give aniline (IV). This was condensed with Z-D-Phe (V) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide.HCl (EDC) and 1-hydroxybenzotriazole (HOBt) to yield amide (VI), which was deprotected to amine (VII) by hydrogenolysis in the presence of Pd/C. Subsequent coupling with Z-Pro (VIII), followed by hydrogenolytic deprotection produced (IX). This was coupled with methyl oxalyl chloride (X) to afford (XI). Then, treatment with trifluoroacetic acid in CH2Cl2 gave acid (XII). Finally, dipeptide (XV) (obtained by coupling of protected 3-amino-2-hydroxy-4-phenylbutyric acid (XIII) with tert-butyl prolinamide (XIV)), was condensed with acid (XII) to produce the title compound.