Sodium hydride → N-[1-(4-Bromo-phenyl)-cyclopropanecarbonyl]-methanesulfonamide

Participants

Reaction Steps

In a 100 ml, round-bottomed flask, 1-(4-bromo-phenyl)-cyclopropanecarboxylic acid (4 g, 16.6 mmol) was combined with DCM (15 mL) and 3 drops of DMF to give a white suspension. To this was added drop wise a clear solution of oxalyl chloride (6.96 g, 4.8 mL, 54.8 mmol) dissolved in DCM (6 mL). After 10 min, the mixture became clear and the reaction was stirred at room temperature for 2 hr. The reaction was concentrated, dried from toluene and hexanes, and stored in a freezer overnight. In a 200 mL round-bottomed flask, NaH (60% mineral dispersion, 876 mg, 36.5 mmol) was washed with hexanes and the resulting solid was diluted with DMF (6 mL) to give a white suspension. The suspension was cooled in an ice bath and methanesulfonamide (3.16 g, 33.2 mmol) dissolved in DMF (6 mL) was added drop wise under nitrogen. After addition (5 min) the ice bath was removed and the reaction was warmed to room temperature overnight. The reaction was cooled in an ice bath, the acid chloride previously prepared and dissolved in DMF (6 mL) was added drop wise, and the reaction was warmed to room temperature overnight. The reaction was diluted with 0.2 N HCl (200 mL) and extracted with EtOAc (2×100 mL). The organic layers were washed with brine, combined, dried over MgSO4, and concentrated. The crude material was dissolved in minimal DCM and purified by flash chromatography (silica gel, 0% to 60% EtOAc in hexanes, 0.5% AcOH). The appropriate fractions were combined, concentrated, and dried from DCM/hexanes yielding N-[1-(4-bromo-phenyl)-cyclopropanecarbonyl]-methanesulfonamide (2.74 g, 51.9% yield) as a white solid. LC/MS calcd. for C11H12BrNO3S (m/e) 317/319, obsd. 318/320 (M+H, ES+).

Provenance & Evidence