(2-[3-Cyclopentyl-2-(4-nitro-phenyl)-propionylamino]-thiazol-4-yl}-acetic acid methyl ester → {2-[2-(4-Amino-phenyl)-3-cyclopentyl-propionylamino]-thiazol-4-yl}-acetic acid methyl ester

A solution of (2-[3-cyclopentyl-2-(4-nitro-phenyl)-propionylamino]-thiazol-4-yl}-acetic acid methyl ester (prepared in Example 24, 75.3 mg, 0.18 mmol) in ethyl acetate (25 mL) was treated with 10% palladium on activated carbon. The reaction mixture was stirred under hydrogen gas at 60 psi at 25° C. for 4 h. The catalyst was then filtered off through a pad of celite (ethyl acetate). The filtrate was concentrated in vacuo to give {2-[2-(4-amino-phenyl)-3-cyclopentyl-propionylamino]-thiazol-4-yl}-acetic acid methyl ester (64.5 mg, 93.3%) as a tan oil: EI-HRMS m/e calcd for C20H25N3O3S (M+) 387.1616, found 387.1612.