Triethylamine → HCID 66951785, compound

Participants

Reaction Conditions

Reaction Steps

To a mixture of (1R)-2-acetyloxy-1-methylethyl (2S)-3-(3,4-dihydroxyphenyl)-2-[(tert-butoxy)carbonylamino]propanoate (19) (8.9 g, 22.4 mmol) and ethyl chloroformate (5.30 mL, 55.3 mmol) in anhydrous dichloromethane, triethylamine (7.7 mL, 55.3 mmol) was added at 0° C. The reaction mixture was stirred at 0° C. for 1 hour. The solution was partitioned between dichloromethane and 10% citric acid and washed with water. The organic layer was dried over MgSO4, and concentrated to dryness. Chromatography (30% ethyl acetate in hexane) provided the title compound (20) (11.5 g, 95% yield) as a white, foamy solid. 1H NMR (400 MHz, CDCl3): δ 1.17 (d, J=6.8 Hz, 3H), 1.37 (t, J=7.2 Hz, 3H), 1.37 (t, J=7.2 Hz, 3H), 1.43 (s, 9H), 2.05 (s, 3H), 3.04 (m, 2H), 4.00 (dd, J=12.0, 6.8 Hz, 1H), 4.14 (dd, J=12.0, 3.2 Hz, 1H), 4.32 (q, J=7.2 Hz, 4H), 4.54 (dd, J=12.8, 6.4 Hz, 1H), 5.02 (d, J=8.0 Hz, 1H, NH), 5.12 (m, 1H), 7.05 (dd, J=8.0, 2.0 Hz, 1H), 7.08 (d, J=2.0 Hz, 1H), 7.19 (d, J=8.0 Hz, 1H). MS (ESI) m/z 564.1 (M+Na)+ and 540.1 (M−H)−.

Provenance & Evidence