Potassium ethylxanthate → 6-Cyano-5-fluorobenzo[d]thiazole-2-thiolate potassium salt

A mixture of 4-amino-2,5-difluorobenzonitrile (1.0 g, 6.5 mmol) and O-ethylxanthic acid potassium salt (1.2 g, 7.8 mmol) in DMF (15 mL) was heated at reflux for 6 h. The mixture was cooled to rt and partitioned between EtOAc (200 mL) and 1 M aq Na2CO3 (100 mL). The organic layer was separated and the aqueous layer was extracted with additional EtOAc (2×200 mL). The combined organic layers were washed with brine (100 mL), dried over Mg2SO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography eluting with 2% MeOH in DCM to afford 6-cyano-5-fluorobenzo[d]thiazole-2-thiolate potassium salt (1.94 g) as an orange solid. LCMS (ESI) m/z 211 (M+H)+.

1. temperaturewas heated
2. temperatureat reflux for 6 h
3. custompartitioned between EtOAc (200 mL) and 1 M aq Na2CO3 (100 mL)
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with additional EtOAc (2×200 mL)
6. washThe combined organic layers were washed with brine (100 mL)
7. dry with materialdried over Mg2SO4
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customThe residue was purified by silica gel flash chromatography
11. washeluting with 2% MeOH in DCM

ORD record

ord-5e03d6dbc7344310a223eeb5fa529fe2

Source dataset

uspto-grants-2015_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08952058B2