Sulfuric Acid → 3-Amino-6-chloro-2-hydroxy-N-methoxy-N-methyl-benzenesulfonamide

2-tert-Butyl-6-chloro-benzooxazole-7-sulfonic acid methoxy-methyl-amide (4.8 g, 14.42 mmol) in dioxane (55 ml) and water (20 ml) was treated with concentrated sulphuric acid (20 ml) added dropwise over 30 minutes maintaining the temperature <30° C. The reaction mixture was heated at reflux for 2.5 h and then allowed to cool to RT. Dioxane was removed in vacuo and the resulting aqueous residue was basified with sat. NaHCO3 solution (250 ml) to pH12. The reaction mixture was extracted with EtOAc (3×200 ml) and the combined organic extracts were washed with water (3×100 ml) sat. brine (100 ml), dried (MgSO4) and concentrated in vacuo to afford the title compound as a brown solid; [M+H]+ 266.

1. additionadded dropwise over 30 minutes
2. temperaturemaintaining the temperature <30° C
3. temperatureThe reaction mixture was heated
4. temperatureat reflux for 2.5 h
5. customDioxane was removed in vacuo
6. extractionThe reaction mixture was extracted with EtOAc (3×200 ml)
7. washthe combined organic extracts were washed with water (3×100 ml) sat. brine (100 ml)
8. dry with materialdried (MgSO4)
9. concentrationconcentrated in vacuo

ORD record

ord-68413df9fb4e4afa89ff027715cb2f63

Source dataset

uspto-grants-2011_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07989497B2