Cesium carbonate → (S)-1-(4-(cyclopropanecarbonyl)-2-methyl-6-(1-(pyrazin-2-ylmethyl)-1H-pyrazol-4-yl)-3,4-dihydroquinoxalin-1(2H)-yl)ethanone

Participants

Reaction Conditions

Reaction Steps

A 40-mL sealed tube was charged with (S)-1-(4-(cyclopropanecarbonyl)-2-methyl-6-(1H-pyrazol-4-yl)-3,4-dihydroquinoxaline-1(2H)-yl)ethan-1-one (100 mg, 0.31 mmol), 3-(chloromethyl)-3-methyloxetane (100 mg, 0.83 mmol), cesium carbonate (300 mg, 0.92 mmol), and acetonitrile (10 mL). The resulting mixture was stirred overnight at 70° C. After cooling to room temperature, the reaction mixture was filtered through a short pad of celite and concentrated under vacuum. The residue was purified by Prep-HPLC with the following conditions: Column, SunFire Prep C18, 19×150 mm; mobile phase, Phase A: water (0.05% NH4HCO3), Phase B: CH3CN (12% CH3CN up to 64% in 14 min); Detector, UV220&254 nm. This afforded (S)-1-(4-(cyclopropanecarbonyl)-2-methyl-6-(1-((3-methyloxetan-3-yl)methyl)-1H-pyrazol-4-yl)-3,4-dihydroquinoxaline-1(2H)-yl)ethanone (33.4 mg, 27%) as an off-white solid. 1H NMR (300 MHz, CD3OD) δ ppm 0.75-0.88 (m, 1H), 0.95-1.10 (m, 3H), 1.17 (d, J=6.30 Hz, 3H), 1.27 (s, 3H), 2.01-2.10 (m, 1H), 2.22 (s, 3H), 2.85-2.98 (m, 1H), 4.35-4.42 (m, 4H), 4.73-4.78 (m, 3H), 4.89-5.01 (m, 1H), 7.39-7.56 (m, 2H), 7.73 (s, 1H), 7.90 (s, 1H), 8.11 (s, 1H). MS (ESI, pos. ion) m/z 409 [M+H]+.

Provenance & Evidence