反应详情

To a stirred mixture of chlorzoxazone (10 g, 58.9 mmol) and CH2Cl2 (˜500 cm3) was added chlorosulphonic acid (4.3 cm3, 64.8 mmol) at room temperature. The reaction was left at room temperature for a week whereupon all the solvent had evaporated leaving a white solid. NMR showed a 1:2 mixture of product and starting material respectively. This crude was extracted with H2O (3×15 cm3), then the aqueous was concentrated in vacuo to a sticky solid which was washed with CH2Cl2 (4×40 cm3) to yield 5-Chloro-2-oxo-2,3-dihydro-benzooxazole-6-sulfonic acid as a fine white solid; δH (300 MHz; D6 DMSO) 7.10 (1H, s, Ar—H), 7.68 (1H, s, Ar—H) and 11.80 (1H, s, N—H); LCMS retention time ˜0.47 min, m/z (FIANEG) 247.9 [Cl35 (M−H)−, 100%] and 249.9 [Cl37 (M−H)−, 33%].

1. waitThe reaction was left at room temperature for a week whereupon all the solvent
2. customhad evaporated
3. customleaving a white solid
4. additiona 1:2 mixture of product
5. extractionThis crude was extracted with H2O (3×15 cm3)
6. concentrationthe aqueous was concentrated in vacuo to a sticky solid which
7. washwas washed with CH2Cl2 (4×40 cm3)