A solution of 2-(4-benzyloxy-phenyl)-3-cyclopentyl-propionic acid (0.15 g, 0.46 mmol) in methylene chloride (4.6 mL) was cooled to 0° C. and then treated with a 2.0M solution of oxalyl chloride in methylene chloride (0.25 mL, 0.50 mmol) and a few drops of N,N-dimethylformamide. The reaction mixture was stirred at 0° C. for 10 min and at 25° C. for 30 min. The reaction mixture was then treated with a solution of 2-aminothiazole (0.10 g, 1.01 mmol) and N,N-diisopropylethylamine (0.19 mL, 1.10 mmol) in tetrahydrofuran (2.3 mL). The reaction mixture was stirred at 25° C. for 18 h. At this time, the reaction was concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh 80/20 hexanes/ethyl acetate) afforded 2-(4-benzyloxy-phenyl)-3-cyclopentyl-N-thiazol-2-yl-propionamide (119.4 mg, 63.5%) as a white solid: mp 48-50° C.; EI-HRMS m/e calcd for C24H26N2O2S (M+) 406.1715, found 406.1716.
