(R)-2-Amino-1-((S)-4-(4-chlorophenyl)-4-hydroxy-3,3-dimethylpiperidin-1-yl)-3-methylbutan-1-one (25 mg, 0.067 mmol), (±)-cis-3-(1-methyl-1H-tetrazol-5-yl)cyclohexanecarboxylic acid (17 mg, 0.080 mmol), HOBT (12 mg, 0.080 mmol), EDC (15 mg, 0.080 mmol) and triethylamine (0.019 mL, 0.133 mmol) were mixed in methylene chloride (3 mL) at 25° C. with stirring. The reaction was stirred for 20 hours then washed with sat'd sodium bicarbonate. The methylene chloride layer was dried over sodium sulfate and concentrated in vacuo to give a white glass which was purified over silica gel (1:1 Hexanes/EtOAc to 100% EtOAc to 4:1 methylene chloride) to obtain (±)-cis-N—((R)-1-((S)-4-(4-chlorophenyl)-4-hydroxy-3,3-dimethylpiperidin-1-yl)-3-methyl-1-oxobutan-2-yl)-3-(1-methyl-1H-tetrazol-5-yl)cyclohexanecarboxamide (35 mg, 0.066 mmol, 99% yield) as a white glass. MS found: (M+H)+=531.46.
