反应详情

To a solution of diethyl 1H-indole-2,6-dicarboxylate (Intermediate A, 1.9 g, 7.4 mmol), tert-butyl (3-hydroxy-2-methylpropyl)carbamate (2.8 g, 14.8 mmol) and triphenylphosphine (4.9 g, 18.5 mmol) in THF (35 mL) at 0° C. is added diisopropyl azodicarboxylate (3.8 mL, 18.5 mmol). The mixture is stirred for 16 h at room temperature and then the solvent is removed. The residue is filtered through a pad of silica (300 g, 240-400 mesh) using 30% EtOAc in heptane to afford of mixture of the title compound and diethyl 1H-indole-2,6-dicarboxylate (3.2 g) which is used in the next step without further purification.

1. customthe solvent is removed
2. filtrationThe residue is filtered through a pad of silica (300 g, 240-400 mesh)