Trifluoroacetic acid → 3-[2-[3-Amino-6-[4-(4-piperidylsulfonyl)phenyl]pyrazin-2-yl]ethynyl]phenol

Participants

Reaction Steps

Crude tert-butyl 4-[4-[5-amino-6-[2-(3-hydroxyphenyl)ethynyl]pyrazin-2-yl]phenyl]sulfonylpiperidine-1-carboxylate (184.3 mg, 0.3447 mmol—assumed quantitative yield from Step 3) was dissolved in DCM (5 mL) and TFA (1 mL, 12.98 mmol) was added. The reaction mixture was stirred at ambient temperature for 4 hours. The solvent was removed in vacuo and the residue azeotroped with DCM (×2) and ether (×2). The material was purified by reverse phase preparative HPLC [Waters Sunfire C18, 10 μM, 100 Å column, gradient 10%-95% B (solvent A: 0.05% TFA in water; solvent B: CH3CN) over 16 minutes at 25 mL/min]. The fractions were collected and freeze-dried to give the mono-TFA salt of the title compound as a yellow solid (10.3 mg, 5% Yield). 1H NMR (400.0 MHz, DMSO) δ 1.65-1.74 (m, 2H), 2.06 (d, 2H), 2.85-2.90 (m, 2H), 3.36 (d, 2H), 3.59-3.65 (m, 1H), 6.89 (dd, 1H), 7.14-7.21 (m, 2H), 7.27 (t, 1H), 7.90 (d, 2H), 8.23 (br s, 1H), 8.28 (d, 2H), 8.54 (br s, 1H), 8.77 (s, 1H) and 9.78 (s, 1H) ppm; MS (ES+) 435.1.

Provenance & Evidence