2-Thiophenesulfonyl chloride → Ethyl 4-methyl-7-[(2-thienylsulfonyl)amino]-1H-indole-2-carboxylate

Participants

Reaction Steps

To a mixed solution of ethyl 7-amino-4-methyl-1H-indole-2-carboxylate (0.71 g) and pyridine (20 mL) was added 2-thiophenesulfonyl chloride (0.78 g) under ice-cooling, and the mixture was stirred at room temperature for 2 days. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with ethyl acetate, washed with aqueous citric acid solution, aqueous sodium hydrogencarbonate solution and brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The obtained residue was subjected to silica gel column chromatography (ethyl acetate:hexane=5:95-20:80), and the obtained crystals were recrystallized from ethyl acetate-hexane to give the title compound (957 mg, yield 81%) as colorless needle crystals. melting point 180-181° C.

Provenance & Evidence