Diisopropylethylamine → 7-((4-(4-chlorophenyl)piperazin-1-yl)methyl)-4-isopropyl-3,4-dihydropyrido[2,3-b]pyrazin-2(1H)-one

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Reaction Conditions

Reaction Steps

The 7-(hydroxymethyl)-4-isopropyl-3,4-dihydropyrido[2,3-b]pyrazin-2(1H)-one (100 mg, 0.452 mmol) was weighed into a vial and taken up as a suspension in propiononitrile (1 mL). Next was added (cyanomethyl)trimethylphosphonium iodide (132 mg, 0.542 mmol) followed by DIEA (0.237 mL, 1.356 mmol). To the stirred white suspension was then added the 1-(4-chlorophenyl)piperazine hydrochloride (116 mg, 0.50 mmol). The reaction was stirred overnight at 90° C. The crude reaction was cooled to room temperature and concentrated to a residue, then taken up in DMSO (3 mL) and purified via HPLC (55-90% acetonitrile in water, ammonium bicarbonate buffer). The fractions were combined and concentrated until a white solid precipitated. The precipitate was filtered off and dried in vacuum to afford the title compound (46.6 mg, 26%) as a white solid. 1H NMR (DMSO-d6) δ (ppm): 10.49 (s, 1H), 7.63 (d, J=2.0 Hz, 1H), 7.21 (d, J=9.1 Hz, 2H), 6.97 (d, J=1.8 Hz, 1H), 6.92 (d, J=9.1 Hz, 2H), 4.74-4.87 (m, 1H), 3.81 (s, 2H), 3.33 (d, J=2.0 Hz, 2H), 3.01-3.15 (m, 4H), 2.41-2.48 (m, 4H), 1.12 (d, J=6.8 Hz, 6H). [M+H] calc'd for C21H26ClN5O, 400; found, 400.

Provenance & Evidence