Triethylamine → (R)-[3-oxo-1-(2,4,5-trifluoro-benzyl)-3-(3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl)-propyl]-carbamic acid tert-butyl ester

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Reaction Steps

(R)-3-tert-Butoxycarbonylamino-4-(2,4,5-trifluoro-phenyl)-butyric acid 1f (8.6 g, 45 mmol) and 9.4 mL of triethylamine were dissolved in 300 mL of dichloromethane. After stirring for 5 minutes, 3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine 1k (15.0 g, 45 mmol) and bis(2-oxo-3-oxazolidinyl)phosphinic chloride (17.1 g, 67.3 mmol) were added to the solution successively. The reaction mixture was reacted for 2 hours and then concentrated under reduced pressure. The resulting residues were purified by silica gel column chromatography with system B as eluant to obtain the title compound tert-Butyl (R)-[3-oxo-1-(2,4,5-trifluoro-benzyl)-3-(3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl)-propyl]-carbamate 1m (20.0 g, yield 88%) as a white solid. 1H NMR (400 MHz, CD3OD, ppm): δ 7.25 (m, 1H), 7.11 (m, 1H), 7.032 (s, 1H), 4.93 (m, 2H), 4.35 (m, 3H), 4.05 (m, 2H), 2.99 (m, 2H), 2.73 (m, 2H), 1.34 (s, 9H).

Provenance & Evidence