Diisopropylethylamine → HCID 86702805, compound

Participants

Reaction Steps

To a solution of (R)-2-(tert-butoxycarbonylamino)-3-(4-(trifluoromethyl)phenyl)propanoic acid (LXVI) (1.17 g, 3.5 mmol) and 6-amino-3,3-dimethylbenzo[c][1,2]oxaborol-1(3H)-ol (XCVIII) (0.62 g, 3.5 mmol) in DCM (35 mL) were added DIPEA (1 mL, 5.3 mmol) and HATU (1.4 g, 3.7 mmol). The mixture was stirred overnight at room temperature. The reaction mixture was diluted with DCM and washed sequentially with 1 M aqueous HCl, 1 M aqueous NaOH, and brine, and was dried over MgSO4. The solvent was evaporated and the crude product was purified by flash chromatography using on a first column (DCM/MeOH 500/1→300/1→200/1→100/1), and on a second column (hexane/EtOAc 5/1→4/1→3/1), to give 1.00 g of pure (R)-tert-butyl 1-(1-hydroxy-3,3-dimethyl-1,3-dihydrobenzo[c][1,2]oxaborol-6-ylamino)-1-oxo-3-(4-(trifluoromethyl)phenyl)propan-2-ylcarbamate (CLXII) as an off-white solid (1.0 g, 2.03 mmol, 60% yield). 1H NMR (CDCl3) δ ppm 1.40 (s, 9H), 1.50 (s, 6H), 3.13 (dd, J=13 Hz, J=14 Hz, 1H), 3.27 (dd, J=13 Hz, J=13 Hz, 1H), 4.48-4.60 (brs, 1H), 5.13-5.26 (brs, 1H), 7.17 (d, J=8 Hz, 1H), 7.26 (d, J=2 Hz, 1H), 7.36 (d, J=5 Hz, 2H), 7.55 (d, J=5 Hz, 2H), 7.58 (d, J=8 Hz, 1H), 8.11-8.16 (brs, 1H); 19F NMR (CDCl3) δ ppm −61.88 (s, 3F); ESIMS found for C24H28BF3N2O5 m/z 493.6 (M+H).

Provenance & Evidence