Diisopropylethylamine → trans-3-(3-Bromophenyl)-1-(4-cyclobutylpiperazin-1-yl)prop-2-en-1-one

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Reaction Steps

In a 500 mL round bottom flask were added trans-3-(3-bromophenyl)acrylic acid (10.0 g, 44.0 mmol), HATU (20.1 g, 52.9 mmol), anhydrous DMF (130 mL) and DIPEA (18.4 mL, 0.11 mol). This mixture was left stirring for 30 min. 1-cyclobutylpiperazine hydrochloride (10.3 g, 48.5 mmol), DMF (20 mL) and DIPEA (20 mL, 0.11 mol) were added to another flask and the resulting mixture stirred until the solution was homogeneous. The solution containing the amine was added to the first solution dropwise and stirred overnight at RT. The DMF was concentrated in vacuo at 60° C. and the resulting semi-solid was dissolved with EtOAc (800 mL) and NaHCO3 sat. (300 mL). The aq. phase was separated and extracted with EtOAc (3×150 mL). The organic phase was dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The resulting brown oil was purified by flash-chromatography (DCVC) eluting with Hexane/EtOAc/NH4OH 100:0:0 to 0:99:1 to afford 19 g 33A (>100% yield) as a beige solid. 1H NMR (300 MHz, CHLOROFORM-d) δ ppm 1.62-2.14 (m, 6H) 2.32-2.47 (m, 4H) 2.73-2.86 (m, 1H) 3.58-3.83 (m, 4H) 6.86 (d, J=15.5 Hz, 1H), 7.20-7.28 (m, 1H), 7.44 (dd, J=15.0, 7.9 Hz, 2H), 7.56 (d, J=15.4 Hz, 1H), 7.65 (t, J=1.7 Hz, 1H).

Provenance & Evidence