Pyridine → [4-(3-cyano-1-cyclobutyl-6-ethoxy-1H-indol-2-yl)-phenyl]-carbamic acid 2-(2-methoxy-ethoxy)-ethyl ester

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Reaction Steps

2-(4-Aminophenyl)-1-cyclobutyl-6-ethoxy-1H-indole-3-carbonitrile (40 mg, 0.12 mmol), prepared as in example 1CM, step B, is combined with 4-nitrophenyl chloroformate (60 mg, 0.30 mmol), DCE (0.4 mL), and pyridine (25 μL, 0.31 mmol). This suspension is stirred at room temperature for 1 h. 2-(2-methoxyethoxy)ethanol (150 μL, 1.25 mmol) is added. This mixture is heated at 80° C. overnight. The reaction mixture is then diluted in CH2Cl2 and is washed with dilute aqueous NaOH to remove the yellow nitrophenol by-product. The organic layer is dried and concentrated. Purification by silica gel chromatography (CH2Cl2) yields [4-(3-cyano-1-cyclobutyl-6-ethoxy-1H-indol-2-yl)-phenyl]-carbamic acid 2-(2-methoxy-ethoxy)-ethyl ester (51 mg, 89%) as a white solid.

Provenance & Evidence