Lithium Hydroxide → (S)-2-(7-(tert-butoxycarbonyl)-3-phenyl-5,6,7,8-tetrahydroimidazo[1,5-a]pyrazine-1-carboxamido)-3,3-dimethylbutanoic acid

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Reaction Conditions

Reaction Steps

Intermediate 22A (2.73 g, 5.80 mmol) was dissolved in THF (20 mL) and cooled to 0° C. Lithium hydroxide (0.70 g, 29 mmol) solution in water (4 mL) was added and the mixture was stirred on ice bath for 6 hours. The mixture was concentrated under reduced pressure, cooled in an ice bath and acidified to pH 4 with 1N HCl. The resulting white precipitate was filtered, washed with water and dried in a vacuum oven at 40° C. to provide Intermediate 22B (2.29 g, 86%) as a white solid. 1H-NMR (400 MHz, DMSO-d6) δ: 0.97 (s, 9H), 1.44 (s, 9H), 3.67 (m, 2H), 4.14 (t, 2H), 4.48 (d, 1H), 4.84 (s, 2H), 7.49 (m, 3H), 7.72 (m, 2H); LCMS (+ESI) m/z 457.2 [M+H]+.

Provenance & Evidence