1,1'-Carbonyldiimidazole → tert-butyl (R)-{2-[7-(2-methanesulfonylamino-2-oxo-ethoxy)-1H-indol-3-yl]-1-methylethyl}carbamate

Participants

Reaction Conditions

Reaction Steps

A solution of (R)-[3-(2-(tert-butoxycarbonylamino)propyl)-1H-indol-7-yloxy]acetic acid (0.30 g, 0.86 mmol) and carbonyldiimidazole (0.21 g, 1.3 mmol) in dimethylformamide (10 mL) is stirred at room temperature for 3 days. To the mixture are added methanesulfonamide (0.16 g, 1.7 mmol) and 1,8-diazabicyclo[5.4.0]undeca-7-ene (0.26 mL, 1.7 mmol), and the mixture is stirred at 50° C. for 4 hours. After cooling, to the mixture is added water (0.1 mL), and the mixture is concentrated. The residue is purified by silica gel column chromatography (methanol/chloroform=1/10→1/3), and the resultant is dissolved in ethyl acetate, washed with a 0.05N hydrochloric acid (×2) and saturated brine, and further dried over magnesium sulfate and concentrated to give the desired tert-butyl (R)-{2-[7-(2-methanesulfonylamino-2-oxo-ethoxy)-1H-indol-3-yl]-1-methylethyl}carbamate (0.14 g, yield: 38%).

Provenance & Evidence