Trifluoroacetic acid → 5-(4-Isopropylsulfonylphenyl)-3-[3-[4-[(tetrahydropyran-4-ylamino)methyl]phenyl]isoxazol-5-yl]pyrazin-2-amine

Participants

Reaction Steps

A suspension of tert-butyl tert-butoxycarbonyl(3-(3-(4-(((tert-butoxycarbonyl)(tetrahydro-2H-pyran-4-yl)amino)methyl)phenyl)isoxazol-5-yl)-5-(4-(isopropylsulfonyl)phenyl)pyrazin-2-yl)carbamate (A-6) (410 g; 492 mmol) in CH2Cl2 (410 mL) is stirred at ambient temperature in a flask. TFA (841 g, 568 mL; 7.4 mol) is added while maintaining the reaction temperature between 20-25° C. The solution is stirred at ambient temperature for about 3 h when analysis shows reaction completion. The solution is cooled to about 5-10° C. and diluted with EtOH (3.3 L) while maintaining the temperature below 20° C. A 5.0 M aqueous solution of NaOH (1.77 L; 8.85 mol) is added while allowing the reaction temperature to rise from about 14° C. to about 42° C. The suspension is heated at 70-75° C. for 6 h while removing distillate. The suspension is allowed to cool to ambient temperature. The solid is collected by filtration and the filter-cake is washed with water (4×1.64 L). The filter-cake is washed with EtOH (2×820 mL) and dried to afford 5-(4-(isopropylsulfonyl)phenyl)-3-(3-(4-(((tetrahydro-2H-pyran-4-yl)amino)methyl)phenyl) isoxazol-5-yl)pyrazin-2-amine (Compound I-1) (257 g; 98% yield, 99.5 area % purity by HPLC) as a yellow powder.

Provenance & Evidence