Hydrochloric Acid → 2-Chloro-4,6-difluorobenzothiazole

To a solution containing copper chloride (II) (0.87 g, 6.45 mmol) and tri(ethylene glycol) dimethyl ether (3 mL) in acetonitrile (50 mL) was added isoamyl nitrite (0.94 g, 8.06 mmol), and the reaction mixture was stirred at rt for 30 minutes. To this suspension was added dropwise a solution of 4,6-difluoro-1,3-benzothiazol-2-amine (1.0 g, 5.37 mmol) in tri(ethylene glycol) dimethyl ether (5 mL). The reaction mixture was stirred at rt for 10 minutes, and then heated at 50° C. for 2.5 h. The reaction mixture was cooled to rt, and then poured cautiously into cold aqueous 6 M HCl (200 mL). The solution was extracted with EtOAc. The organic layer was washed with HCl (1.0 M), water and brine, filtered and concentrated down to afford 2-chloro-4,6-difluoro-1,3-benzothiazole (1.1 g, 99%). 1H NMR (400 MHz, DMSO-d6) 7.05 (m, 1H), 7.36 (m, 1H).

1. stirringThe reaction mixture was stirred at rt for 10 minutes
2. temperatureheated at 50° C. for 2.5 h
3. temperatureThe reaction mixture was cooled to rt
4. extractionThe solution was extracted with EtOAc
5. washThe organic layer was washed with HCl (1.0 M), water and brine
6. filtrationfiltered
7. concentrationconcentrated down

ORD record

ord-29bbf8865b504dceacd13da25e81dc7a

Source dataset

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08013166B2