N-Methyl-N-[(1R)-1-phenylpropyl]-2-(4-piperidinyl)-4-thiazolecarboxamide (i.e. the product of Example 1, Step E) (206 mg, 0.6 mmol) was dissolved in 4 mL of dry dichloromethane. To this reaction mixture was added triethylamine (90 μL, 0.65 mmol), 2,5-dimethylbenzeneacetic acid (98 mg, 0.6 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (125 mg, 0.65 mmol) and a catalytic amount of 4-(dimethylamino)pyridine (˜1 mg). The mixture was shaken overnight at ambient temperature, passed through a 5 mL capacity ChemEluten™, diatomaceous filter tube, pretreated with 3 mL of 1 N aqueous hydrochloric acid solution and eluted with 2 column volumes of dichloromethane. The dichloromethane solution was concentrated under reduced pressure, and the residue was purified by silica gel chromatography using acetone to give 276 mg of the title product, a compound of the present invention as a light yellow oil.
