Cesium carbonate → HCID 59863937, compound

Participants

Reaction Steps

To a stirred solution of tert-butyl [(2R,3S)-4-oxo-2-phenyl-2,3,4,5-tetrahydro-1,5-benzoxazepin-3-yl]carbamate (67a) (150 mg, 0.423 mmol) in dry DMF (4 mL) under nitrogen was added methyl bromoacetate (97 mg, 0.634 mmol) and powdered cesium carbonate (207 mg, 0.635 mmol). The mixture was stirred overnight at ambient temperature then diluted with water and extracted with ethyl acetate three times. The residue from the organic extract was purified by flash chromatography on silica gel eluting with 4:1 (v/v) hexane:ethyl acetate to afford the title compound (175 mg, 97%) as a white solid. TLC Rf=0.20 (4:1 hexane:ethyl acetate). 1H NMR (300 MHz, CDCl3) δ1.38 (s, 9H), 3.80 (s, 3H), 4.54 and 4.69 (AB quartet, 2H, J=17.1 Hz), 4.93 (m, 1H), 5.02 (m, 1H), 5.70 (d, 1H, J=7.0 Hz), 7.19-7.29 (m, 4H), 7.35-7.48 (m, 5H). MS APCI, m/z=327 (M-BOC). LC/MS: 2.76 min.

Provenance & Evidence