反应详情

温度

65 °C

Sodium methoxide (40 mL of a 4 M methanolic solution) was added to a solution of 2-carboxybenzaldehyde 1d (1.000 g, 7.455 mmol) and phthalide 2d (1.119 g, 7.455 mmol) in ethyl acetate (20 mL). The solution was heated at 65° C. for 18 h, concentrated, and acidified with coned HCl. The resulting mixture was diluted with benzene (125 mL), TsOH (100 mg) was added, and the solution was heated for 7 h at reflux in a flask affixed with a Dean-Stark trap. The solution was cooled to room temperature, concentrated, diluted with CHCl3 (150 mL), and washed with sat NaHCO3 (3×50 mL) and sat NaCl (50 mL). The organic layer was dried over sodium sulfate and concentrated to provide indenobenzopyran 4d as an orange solid (1.583 g, 86%): mp 258-259° C. (published mp 257° C.). 1H NMR (CDCl3) δ 8.40 (d, J=8.56 Hz, 1H), 8.32 (d, J=7.93 Hz, 1H), 7.84-7.79 (m, 1H), 7.61-7.39 (m, 5H). Additional details regarding the synthesis of compound 8 are found in Pailer et al., Monatsh Chem., 92:1037-47 (1961), the synthetic disclosure of which is incorporated herein by reference.

1. concentrationconcentrated
2. additionThe resulting mixture was diluted with benzene (125 mL), TsOH (100 mg)
3. additionwas added
4. temperaturethe solution was heated for 7 h
5. temperatureat reflux in a flask
6. temperatureThe solution was cooled to room temperature
7. concentrationconcentrated
8. additiondiluted with CHCl3 (150 mL)
9. washwashed
10. dry with materialThe organic layer was dried over sodium sulfate
11. concentrationconcentrated