反应详情

To a solution of 4-hydroxycoumarin (1.62 g, 10 mmol) in acetone (60 ml) were added 2-bromoacetophenone (1.99 g, 10 mmol) and potassium carbonate (5.53 g, 40 mmol). The mixture was refluxed for 3 h. (monitored by TLC). Evaporation of the solvent gave a residue which was poured into ice water (50 ml). The resulting solid was collected and crystallized from ethyl acetate to afford 4-(2-Oxo-2-phenylethoxy)-2H-1-benzopyran-2-one (2a) (1.76 g, 62.9%) as a needle crystal. mp: 183°-184° C.; IR(KBr) νmax : 1721, 1703, 1626; UV(CHCl3) λmax (log ε): 306 (3.79), 253 (4.28); 1H-NMR (CDCl3): δ5.50 (s, 2H, OCH2), 5.61 (s, 1H, 3-H), 7.26-7.35 (m, 2H, 6- and 8-H), 7.50-7.71 (m, 4H, 5-, 7-H and aromatic H), 7.94-8.02 (m, 3H, aromatic H). Anal. Calcd for C17H12O4 : C, 72.85; H, 4.32. Found: C, 72.85; H, 4.72.

1. temperatureThe mixture was refluxed for 3 h. (monitored by TLC)
2. customEvaporation of the solvent
3. customgave a residue which
4. customThe resulting solid was collected
5. customcrystallized from ethyl acetate