Dimethylformamide → 2-Chloro-5-nitrobenzenesulfonamide

Participants

Reaction Steps

2-chloro-5-nitrobenzenesulfonic acid (44 mmol) was heated at reflux for 3.5 hours in a mixture of thionyl chloride (22 mL) and dimethylformamide (2 mL). After cooling the reaction mixture to room temperature, the solvents were removed under high vacuum. The crude solid was azeotroped with toluene (3×100 mL) to dryness under vacuum. The final residue was taken up in a mixture of toluene (20 mL) and tetrahydrofuran (50 mL) then cooled to 0° C. Ammonia (50 mL) was added to the stirred reaction mixture, then allowed to warm to room temperature overnight. The solution was acidified using 6 M HCl (pH ˜4) and extracted with ethyl acetate (3×100 mL). The combined organics were dried over MgSO4, filtered and then concentrated to dryness under vacuum to yield 2-Chloro-5-nitrobenzenesulfonamide as a light brown solid (3.91 g, 38% over 2 steps).

Provenance & Evidence