反应详情

To a 250 mL round bottom flask charged with 4-cyanobenzoic acid (19.36 g, 0.13 mol) in abs. ethanol (100 mL) was added concentrated sulfuric acid (3 mL). This mixture was heated to reflux for a period of 28 h, then allowed to cool to room temperature overnight. The solvent was removed via rotary evaporation and the resulting off-white residue was taken up in diethyl ether (500 mL). This was then washed with saturated sodium bicarbonate/water solution (5×100 mL), then brine (1×100 mL), and dried over magnesium sulfate. Filtration and concentration yielded an off-white solid. Recrystallization from 95% ethanol (50 mL) yielded product as white crystals (16.85 g, 73%). 1H NMR (400 MHz, CDCl3, δ in ppm) 8.14 (AA′XX′, J=8.6 Hz, 2H), 7.74 (AA′XX′, J=8.6 Hz, 2H), 4.42 (q, J=7.1 Hz, 2H), 1.41 (t, J=7.1 Hz, 3H).

1. temperatureThis mixture was heated
2. temperatureto reflux for a period of 28 h
3. customThe solvent was removed via rotary evaporation
4. washThis was then washed with saturated sodium bicarbonate/water solution (5×100 mL)
5. dry with materialbrine (1×100 mL), and dried over magnesium sulfate
6. filtrationFiltration and concentration
7. customyielded an off-white solid
8. customRecrystallization from 95% ethanol (50 mL)