反应详情

3-Dipropylamino-5-aminochroman (Example 14; 0.60 g, 2.42 mmol) was dissolved in acetic acid (10 ml) and 2,5-dimethoxytetrahydrofuran (0.40 g, 3.0 mmol) was added. The solution was refluxed for 1 hour. The solution was neutralized with NaOH (aq.) and extracted with toluene. The organic phase was dried with sodium sulfate and evaporated to dryness. The residue was purified by flash chromatography on silica gel by elution with ethyl acetate/hexane 1:9 to give the title compound. 13C-NMR: 111.75 21.89 24.81 52.69 53.15 67.94 108.93 115.67 118.22 118.44 121.87 127.22 141.47 155.27

1. temperatureThe solution was refluxed for 1 hour
2. extractionextracted with toluene
3. dry with materialThe organic phase was dried with sodium sulfate
4. customevaporated to dryness
5. customThe residue was purified by flash chromatography on silica gel by elution with ethyl acetate/hexane 1:9