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

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Reaction Steps

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)+.

Provenance & Evidence