Ammonium Chloride → Methyl 3-amino-4-((4-((tert-butoxycarbonyl)amino)phenyl)thio)benzoate

Participants

Reaction Steps

A suspension of 4-(4-tert-butoxycarbonylamino-phenylsulfanyl)-3-nitro-benzoic acid methyl ester (22.8 g, 56 mmol), Fe powder (16.4 g, 282 mmol) and NH4Cl (15.1 g, 282 mmol) in aqueous EtOH [prepared from EtOH (228 mL) and H2O (228 mL)] was gradually heated to reflux and gently refluxed for 2 hours. The reaction mixture was cooled to room temperature and filtered through celite pad. The filtrate was evaporated. The aqueous residue was portioned between AcOEt and H2O, made basic to pH 9 with K2CO3, and then filtered through celite pad. The organic layer was separated, washed with 1-120 and brine, dried over MgSO4 and evaporated. The oily residue was crystallized in the treatment with i-Pr2O (200 mL) and stirred at room temperature for 30 minutes. The resulting crystal was collected by filtration, washed with i-Pr2O and dried at 60° C. overnight under reduced pressure to give the title compound as colorless crystal (13.9 g, 66%).

Provenance & Evidence