Trifluoroacetic acid → 3-amino-4-chloro-5-(1,1-dioxidotetrahydro-2H-isothiazolo[2,3-a]pyrazin-5(3H)-yl)benzonitrile

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Reaction Steps

tert-butyl-(2-chloro-5-cyano-3-(1,1-dioxidotetrahydro-2H-isothiazolo[2,3-a]pyrazin-5(3H)-yl)phenyl)carbamate (70 mg, 0.164 mmol) in DCM (1 mL) was treated with TFA (0.240 mL, 3.12 mmol) at room temperature for 2 h. Solvent was evaporated and the residue was diluted with dichloromethane and washed with saturated sodium bicarbonate. The aqueous layer was extracted with dichloromethane two more times. The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo, the crude product was purified by flash chromatography on silica gel using an automated ISCO system (24 g column, eluting with 0-5% methanol/dichloromethane). 3-amino-4-chloro-5-(1,1-dioxidotetrahydro-2H-isothiazolo[2,3-a]pyrazin-5(3H)-yl)benzonitrile (37 mg) was obtained as a yellow solid.

Provenance & Evidence