Pyridine → Methyl 5-amino-1H-indole-3-carboxylate

Participants

Reaction Steps

To a solution of 3-chloro-2-methylbenzenesulphonyl chloride (124 mg, 0.552 mmol) in dichloromethane (4 mL) was added pyridine (100 μL, 1.3 mmol) and the mixture was stirred under N2 for 5 min, after which time 5-amino-1H-indole-carboxylic acid methyl ester (100 mg, 0.526 mmol) was added. The resulting mixture was stirred for 1.5 h at room temperature, then saturated NaHCO3 solution (15 mL) was added and the mixture was extracted into ethyl acetate (20 mL). The organic phase was washed with brine, dried (Na2SO4), filtered and evaporated to give a residue that was purified using flash chromatography to afford a white solid (129 mg, 65%), single spot at Rf 0.84 (ethyl acetate). mp 216.8-219.3° C., [22], HPLC purity 99+% (tR 2.07 min in 10% water-acetonitrile). 1H NMR (d6-DMSO): δ 11.91 (1H, s), 10.32 (1H, s), 8.03 (1H, d, J=3.0 Hz), 7.82 (1H, d, J=7.9 Hz), 7.70-7.67 (2H, m), 7.37-7.31 (2H, m), 6.95 (1H, dd, J=8.6, 2.0 Hz), 3.77 (3H, s), 2.65 (3H, s). LCMS: 377.09. FAB-MS (MH+, C17H15ClN2O4S): calcd 378.0441, found 378.0439.

Provenance & Evidence