p-Toluenesulfonic acid → Ammonium Hydroxide

Participants

Reaction Steps

A mixture of (±)-ethyl (4-amino-2-oxo-2,3-dihydro-1H-indol-3-yl)acetate from Step B (2.40 g, 10.2 mmol), p-toluenesulfonic acid (195 mg, 1.03 mmol) and AcOH (1 mL) was heated in xylenes (10 mL) at reflux for 24 h, then concentrated to dryness under reduced pressure. The crude product was partially purified by silica gel chromatography, eluting with a gradient of CH2Cl2:MeOH:NH4OH—100:0:0 to 90:9:1, to give a crude sample of the title compound. Further purification was achieved by trituration with CH2Cl2 to give the title compound. MS: m/z=189 (M+1).

Provenance & Evidence