O[C:2]1[C:3](=[O:14])[NH:4][C:5](=[O:13])[C:6]=1[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.CN(C=O)C.C(Cl)(=O)C([Cl:23])=O>ClCCl>[Cl:23][C:2]1[C:3](=[O:14])[NH:4][C:5](=[O:13])[C:6]=1[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1To a suspension of 3-hydroxy-4-phenyl-1H-pyrrole-2,5-dione (25.0 g, 0.13 mol) in dichloromethane (600 mL) under nitrogen was added DMF (36 mL). The suspension was cooled to ice temperature and treated with oxalyl chloride (40.0 g, 0.32 mol). The reaction mixture was subsequently refluxed overnight. After cooling to room temperature silica gel was added and the reaction mixture evaporated to dryness and subjected to flash chromatography (hexane:EtOAc 80:20). Trituration with dichloromethane, filtration and drying gave 17.6 g (64%) of the title compound. 1H NMR (400 MHz, CDCl3) δ 7.96-7.89 (m, 2H), 7.88-7.77 (bs, 1H), 7.55-7.45 (m, 3H).
Wird geladen…
