Dimethylformamide → 2-Chloro-5-nitrobenzenesulfonamide

To a solution of thionyl chloride (11 mL) and 2-chloro-5-nitro-benzenesulfonic acid (4.78 g, 20.1 mmol) was added N,N-dimethylformamide (0.92 μL) and the reaction mixture was heated to reflux for 4 h. Upon cooling, the reaction mixture was azeotroped with toluene (2-3×). The sulfonyl chloride was dissolved in a minimal amount of toluene and then added to a mixture of concentrated aqueous ammonium hydroxide solution (25 mL) and tetrahydrofuran (25 mL) at −10° C. After stirring for 2 h the reaction was quenched by adding a 6.0 M aqueous hydrochloric acid solution until pH 4 was reached. The layers were separated and the organic layer was concentrated in vacuo to a slurry. Pentane was added and the product was isolated by vacuum filtration to afford the desired product, 2-chloro-5-nitrobenzenesulfonamide (2.0 g, 8.48 mmol, 42.4%) as a solid.

1. temperaturethe reaction mixture was heated
2. temperatureto reflux for 4 h
3. temperatureUpon cooling
4. customthe reaction mixture was azeotroped with toluene (2-3×)
5. dissolutionThe sulfonyl chloride was dissolved in a minimal amount of toluene
6. additionadded to a mixture of concentrated aqueous ammonium hydroxide solution (25 mL) and tetrahydrofuran (25 mL) at −10° C
7. customwas quenched
8. additionby adding a 6.0 M aqueous hydrochloric acid solution until pH 4
9. customThe layers were separated
10. concentrationthe organic layer was concentrated in vacuo to a slurry
11. additionPentane was added
12. customthe product was isolated by vacuum filtration

ORD record

ord-b456b17659694e4cba07da77616b1ead

Source dataset

uspto-grants-2009_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07582626B2