Hydrochloric Acid → (R)-7-[3-tert-butoxycarbonyl-4-(2,4,5-trifluorophenyl)butanoyl]-3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-carboxylic acid

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Reaction Steps

Methyl(R)-7-[3-tert-butoxycarbonylamino 5-trifluoro-phenyl)-butyryl]-3-trifluoro methyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-formate 1p (1.8 g, 3.2 mmol) was dissolved in 50 mL of methanol, followed by addition of 10 mL of aqueous sodium hydroxide (4 M). The reaction mixture was stirred for 1 hours. The reaction mixture was adjusted to pH=3-5 with 2 M hydrochloric acid in an ice bath. The mixture was extracted with ethyl acetate (100 mL×3). The combined organic phase was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to obtain the title compound (R)-7-[3-tert-butoxycarbonyl-4-(2,4,5-trifluorophenyl)butanoyl]-3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-carboxylic acid 1q (1.76 g, yield 100%) as a light yellow solid. MS m/z (ESI): 550.9 [M+1]. 1H NMR (400 MHz, CD3OD, ppm): δ 7.29-7.23 (m, 1H), 7.121-7.08 (m, 1H), 5.15-5.03 (m, 2H), 4.41-4.06 (m, 5H), 2.98-2.77 (m, 4H), 1.42-1.26 (m, 9H).

Provenance & Evidence