Chlorosuccinimide → HCID 68706883, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of (R)-2-benzyloxycarbonylamino-3-(2-oxo-2,3-dihydro-benzooxazol-6-yl)-propionic acid methyl ester (373 mg, 1.01 mmol), N-chlorosuccinimide (168 mg, 1.26 mmol), silica gel (EM Scientific, 230-400 mesh, 3.73 g) in dichloroethane (20 mL) was heated at 90° C. for 16 h. After cooling down to room temperature, the solvents were removed in vacuo. The residue was subjected to silica gel chromatography using ethyl acetate/hexanes (1:2) as eluent to afford the title compound (40 mg, 9.8%), also 2-benzyloxycarbonylamino-3-(5-chloro-2-oxo-2,3-dihydro-benzooxazol-6-yl)-propionic acid methyl ester (78 mg, 19%). The structure was confirmed by 2D NMR and by comparison with that of 2-benzyloxycarbonylamino-3-(5-chloro-2-oxo-2,3-dihydro-benzooxazol-6-yl)-propionic acid methyl ester prepared by the reaction shown below. 1H-NMR (CD3COCD3, 500 MHz) δ 7.37-7.27 (m, 5H), 7.18 (d, J=1.0 Hz, 1H), 7.16 (s, 1H), 6.76 (d, J=8.5 hz, 1H), 5.06 (d, J=12.5 Hz, 1H), 5.02 (d, J=12.5 Hz, 1H), 4.55-4.51 (m, 1H), 3.72 (s, 3H), 3.26 (dd, J=14.0, 5.0 Hz, 1H), 3.04 (dd, J=14.0, 9.5 Hz, 1H); 13C-NMR (CD3COCD3, 125 MHz) δ 172.2, 156.4, 154.0, 144.8, 137.6, 133.3, 128.7, 128.2, 128.0, 127.9, 125.0, 66.3, 55.9, 52.0, 37.3; Mass spec. 405 (MH+).

Provenance & Evidence