Reaction Steps
To a solution of (R)-(2-(5-acetyl-4-(trifluoromethyl)pyrimidin-2-yl)-1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methyl acetate (100 mg, 0.181 mmol) in THF (2 mL) and H2O (2 mL) was added LiOH (38 mg, 0.905 mmol). The mixture was stirred at rt for 10 min. The mixture was extracted with EtOAc (3×10 mL). The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under vacuum. The residue was purified by basic preparative HPLC to afford the crude product (53.1 mg, 55.9% yield). The crude product was separated by SFC to afford (R)-1-(2-(8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazin-2(1H)-yl)-4-(trifluoromethyl)pyrimidin-5-yl)ethanone (32.90 mg, isomer 1) as a white solid and (S)-1-(2-(8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazin-2(1H)-yl)-4-(trifluoromethyl)pyrimidin-5-yl)ethanone (16.90 mg, isomer 2) as a white solid. Isomer 1: (R)-1-(2-(8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazin-2(1H)-yl)-4-(trifluoromethyl)pyrimidin-5-yl)ethanone. Analytical chiral HPLC: tR=7.280 min in 15 min chromatography (Method: AS-H_5_5_40_2.35 ML). LC-MS m/z 512.1 [M+H]+. 1H NMR (CD3OD 400 MHz): δ 9.00 (s, 1H), 8.23 (s, 1H), 7.95 (s, 1H), 6.11-6.07 (m, 1H), 5.49-5.32 (m, 1H), 5.10 (s, 2H), 4.54 (dd, J=3.6 Hz and 12.4 Hz, 1H), 4.24 (dt, J=4.8 and 12.0 Hz, 1H), 3.98-3.90 (m, 1H), 3.25 (s, 3H), 2.61-2.57 (m, 1H), 2.56 (s, 3H), 1.29 (d, J=6.8 Hz, 3H), 1.07 (d, J=6.8 Hz, 3H). Isomer 2: (S)-1-(2-(8-(hydroxymethyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazin-2(1H)-yl)-4-(trifluoromethyl)pyrimidin-5-yl)ethanone Analytical chiral HPLC: tR=8.485 min in 15 min chromatography (Method: AS-H_5_5_40_2.35 ML). LC-MS m/z 512.1 [M+H]+. 1H NMR (CD3OD 400 MHz): δ 9.00 (s, 1H), 8.24 (s, 1H), 7.96 (s, 1H), 6.12-6.08 (m, 1H), 5.48-5.31 (m, 1H), 5.11 (s, 2H), 4.56 (dd, J=3.6 Hz and 12.4 Hz, 1H), 4.24 (dt, J=4.8 and 12.0 Hz, 1H), 3.98-3.91 (m, 1H), 3.26 (s, 3H), 2.61-2.58 (m, 1H), 2.56 (s, 3H), 1.29 (d, J=6.0 Hz, 3H), 1.07 (d, J=6.8 Hz, 3H).
