1-Pyrrolidinecarboxylic acid, 2,2'-([1,1'-biphenyl]-4,4'-diyldi-1H-iMidazole-5,2-diyl)bis-, 1,1'-bis(1,1-diMethylethyl) ester, (2S,2'S)-

1009119-82-7

1007882-23-6

General procedure for the synthesis of (2S,2'S)-di-tert-butyl 2,2'-(4,4'-([1,1'-biphenyl]-4,4'-diyl)bis(1H-imidazole-4,2-diyl))bis(pyrrolidine-1-carboxylate) from DACLATASVIR INTERMEDIATE - daclatasvir intermediate: a mixture of 3 (2 g, 3.01 mmol) and NH4OAc (4.65 g, 60.3 mmol) in toluene (30 mL) was heated to reflux at 130 °C for 15 hours. Upon completion of the reaction, the volatile components were removed by distillation under reduced pressure. The residue was partitioned between CH2Cl2 and H2O until saturation was reached. Saturated aqueous NaHCO3 was added to neutralize the aqueous phase. The aqueous phase was extracted with CH2Cl2, the organic phases were combined, dried over anhydrous MgSO4, filtered and concentrated under reduced pressure. The residue was purified by fast column chromatography (silica gel; 50% EtOAc/hexane as eluent) to give product 4 as a white solid (1.6 g, 85% yield).