Diisopropylethylamine → (S)-4-acetyl-3-methyl-7-(1-(oxetan-3-yl)-1H-pyrazol-4-yl)-3,4-dihydroquinoxaline-1(2H)-carbonyl chloride

Participants

Reaction Steps

Triphosgene (0.048 g, 0.16 mmol) was added slowly to a solution of (S)-1-(2-methyl-6-(1-(oxetan-3-yl)-1H-pyrazol-4-yl)-3,4-dihydroquinoxaline-1(2H)-yl)ethanone (0.050 g, 0.16 mmol) and N,N-diisopropylethylamine (0.413 g, 3.20 mmol) in 1,2-dichloroethane (20 mL) at room temperature. The resulting solution was stirred for 1 hour at room temperature and then concentrated under vacuum. The crude product was purified via preparative thin layer chromatography (eluting with 1:1 petroleum ether:ethyl acetate) to afford (S)-4-acetyl-3-methyl-7-(1-(oxetan-3-yl)-1H-pyrazol-4-yl)-3,4-dihydroquinoxaline-1(2H)-carbonyl chloride (0.040 g, 67%) as a yellow solid. 1H-NMR (300 MHz, CDCl3, ppm): δ 7.92-7.80 (m, 3H), 7.41-7.38 (m, 1H), 7.26-7.23 (m, 1H), 5.55-5.45 (m, 1H), 5.13-5.08 (m, 5H), 4.58-4.53 (m, 1H), 3.33-3.20 (m, 1H), 2.23 (s, 3H), 1.10 (d, J=6.3 Hz, 3H). MS (ESI, pos. ion) m/z 375, 377 [M+H]+.

Provenance & Evidence