Trifluoroacetic acid → HCID 87404217, compound

Participants

Reaction Steps

Purified N-tert-butoxycarbonyl O-propynyl-L-seryl α,α-dimethylglycine methyl ester 14 (2.27 g, 6.63 mmol) was dissolved in 50% (v/v) TFA in CH2Cl2 and the reaction mixture stirred for 1 h 10 min at room temperature. The solvent and bulk of excess TFA were evaporated and CH2Cl2 (3×20 mL) added and evaporated. Diethyl ether (25 mL) was added causing a white solid to precipitate on standing. The Et2O was decanted off and the residue washed with more Et2O (2×25 mL). After decantation of the Et2O the residue was dried under high vacuum affording the title compound as a white solid (2.10 g, 89%); 1H NMR (200 MHz, DMSO-d6) δ 8.95 (s, 1H, NH), 8.31 (br s, 3H, NH3+), 4.20 (d, J=2.4 Hz, 2H, CH2CCH), 4.02 (dd, J=5.8, 3.8 Hz, 1H, CαH or CHH), 3.88-3.67 (m, 2H, CH2 or CαH/CHH), 3.57 (s, 3H, OCH3), 3.52 (t, J=2.3 Hz, 1H, CCH), 1.39 (s, 3H, CH3), 1.36 (s, 3H, CH3); 13C NMR (75 MHz, DMSO-d6) δ 173.9, 165.7, 158.3 (q, JCF=31 Hz), 117.2 (q, JCF=298 Hz), 79.5, 78.0, 68.0, 58.1, 55.5, 52.1, 52.0, 24.7; HRMS (m/z): M+ calcd. for C11H19N2O4, 243.1344. found, 243.1335; Anal. Calcd. for C13H19F3N2O6: C, 43.82; H, 5.38; N, 7.86. Found: C, 43.8; H, 5.4; N, 7.8.

Provenance & Evidence