To a solution of 3-(2,4-dimethyl-6-(propionyloxy)phenyl)-3-methylbutanoic acid (160 mg, 0.57 mmol) and (S)—N-(5-chloro-2-(1H-tetrazol-1-yl)benzyl)-1-((R)-2-(4-fluorophenyl)-2-hydroxyacetyl)-4,5-dihydro-1H-pyrazole-5-carboxamide (263 mg, 0.57 mmol) in DCM (3 mL) and DMF (3 mL) was added EDC (165 mg, 0.86 mmol) and DMAP (7 mg, 0.06 mmol). The clear colorless solution was stirred at rt for 48 h. The mixture was diluted with DCM and washed with water, 1M HCl and sat NaHCO3. The organic phase was dried, filtered, evaporated and purified by flash chromatography (DCM/EtOAc gradient from 4:1 to 2:1) to give (R)-2-((S)-5-(5-chloro-2-(1H-tetrazol-1-yl)benzylcarbamoyl)-4,5-dihydro-1H-pyrazol-1-yl)-1-(4-fluorophenyl)-2-oxoethyl 3-(2,4-dimethyl-6-(propionyloxy)phenyl)-3-methylbutanoate (380 mg, 92%) as a semisolid.
