Trifluoroacetic acid → (S)-3-(3-(4-(1H-imidazol-2-yl)phenyl)pyrazolo[1,5-a]pyrimidin-5-yl)-4-isopropyloxazolidin-2-one

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Reaction Steps

(S)-4-isopropyl-3-(3-(4-(1-((2-(trimethylsilyl)ethoxy)methyl)-1H-imidazol-2-yl)phenyl)pyrazolo[1,5-a]pyrimidin-5-yl)oxazolidin-2-one (2.09 g, 4.03 mmol) was dissolved in dichloromethane (20 mL) and trifluoroacetic acid (25 mL) was added and the mixture allowed to stir at ambient temperature for 12 hours. The reaction mixture was concentrated and the residue partitioned between saturated aqueous NaHCO3 (50 mL) and EtOAc (100 mL). The aqueous layer was washed with EtOAc. The combined organic extracts were washed with brine, dried (Na2SO4), filtered and concentrated to give a light yellow solid. Purification of the crude material by column chromatography, eluting with a gradient of 0-4% (9:1 MeOH/NH4OH)/EtOAc, provided (S)-3-(3-(4-(1H-imidazol-2-yl)phenyl)pyrazolo[1,5-a]pyrimidin-5-yl)-4-isopropyloxazolidin-2-one as a yellow solid (961.3 mg, 61%). LCMS (APCI+) m/z 389 [M+H]+; 1H NMR (400 MHz, CDCl3) δ 8.57 (d, J=7.8 Hz, 1H), 8.39 (s, 1H), 8.04 (d, J=8.6 Hz, 2H), 8.03 (d, J=7.8 Hz, 1H), 7.89 (d, J=8.6 Hz, 2H), 7.19 (s, 2H), 4.95-4.91 (m, 1H), 4.36-4.45 (m, 2H), 2.83-2.91 (m, 1H), 1.04 (d, J=7.0 Hz, 3H), 0.92 (d, J=7.0 Hz, 3H).

Provenance & Evidence