Potassium Hydroxide → N-[2,4-Difluoro-3-(7-pyridin-4-yl-2,3-dihydro-pyrazolo[5,1-b]thiazol-6-yl)-phenyl]-2,5-difluoro-benzenesulfonamide

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Reaction Steps

To 2,4-difluoro-3-(7-pyridin-4-yl-2,3-dihydro-pyrazolo[5,1-b]thiazol-6-yl)phenylamine (115 mg, 0.54 mmol) in pyridine (3 mL) was added 2,5-difluoro-benzenesulfonyl chloride (88 μL, 0.81 mmol) and the mixture was stirred under nitrogen atmosphere for one hour. The mixture was diluted with ethyl acetate and washed with NaHCO3 saturated solution and with brine. The organic layer was dried over anhydrous sodium sulfate, filtered and dried. The solvent was removed under reduce pressure to give a mixture of mono and bis-sulfonamide. The crude was dissolved in THF (4 mL). A 1 M KOH solution (4 mL) was added and the mixture was stirred at 70° C. overnight. The solvent was removed under reduced pressure and the crude was dissolved in ethyl acetate and washed with NaHCO3 saturated solution twice. The organic layer was dried over sodium sulphate, filtered and the solvent was removed under reduced pressure. N-[2,4-Difluoro-3-(7-pyridin-4-yl-2,3-dihydro-pyrazolo[5,1-b]thiazol-6-yl)-phenyl]-2,5-difluoro-benzenesulfonamide (64 mg, 37%) was isolated by silica gel chromatography column eluting with ethyl acetate 5% in hexane.

Provenance & Evidence