[CH3:1][C:2]1[CH:3]=[C:4]([CH3:12])[C:5]2[O:9][C:8](=[O:10])[NH:7][C:6]=2[CH:11]=1.[H-].[Na+].Br[CH2:16][C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18]>CN(C=O)C>[CH3:1][C:2]1[CH:3]=[C:4]([CH3:12])[C:5]2[O:9][C:8](=[O:10])[N:7]([CH2:16][C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18])[C:6]=2[CH:11]=1To a stirred solution of 5,7-dimethyl-2-benzoxazolinone (200 mg, 1.23 mmol) in DMF (2 mL) was added sodium hydride (59 mg of a 60% dispersion in mineral oil, 1.47 mmol). The mixture was stirred at ambient temperature for 10 min, then tert-butyl bromoacetate (287 mg, 1.47 mmol) was added and stirring was continued for 2 h. The reaction mixture was quenched with H2O and purified directly by HPLC using a reversed phase C18 column and eluting with a gradient of H2O:CH3 CN:CF3 CO2H—90:10:0.1 to 5:95:0.1. Lyophilization provided the title compound. MS: m/z=222 (M−C4H7).
Wird geladen…
