Dimethylformamide → 2-Chloro-5-nitrobenzenesulfonamide

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).

1. customthe solvents were removed under high vacuum
2. customThe crude solid was azeotroped with toluene (3×100 mL) to dryness under vacuum
3. additionThe final residue was taken up in a mixture of toluene (20 mL) and tetrahydrofuran (50 mL)
4. temperaturethen cooled to 0° C
5. additionAmmonia (50 mL) was added to the stirred reaction mixture
6. temperatureto warm to room temperature overnight
7. extractionextracted with ethyl acetate (3×100 mL)
8. dry with materialThe combined organics were dried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated to dryness under vacuum

ORD record

ord-42a61eed151f4ead8d688382c0085fb3

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09388127B2