反应详情

温度

55 °C

To a stirred solution of 34.14 g (0.200 moles) of 4-bromoaniline in 130 ml toluene under N2, 18.00 g (0.220 moles) of diketene was added dropwise over a 10 minute period followed by 15 ml of toluene. The temperature rose to 80° C. during the addition; the solution was then refluxed 20 minutes, cooled to 55° C. and 60 ml of petroleum ether added. An immediate precipitation occurred. The tan-white crystals were filtered and washed with three 100 ml portions of 1:1 toluene/petroleum ether. The product was taken up in hot absolute ethanol and crystallisation induced by addition of toluene to the ethanolic solution. Three crops of crystals from the ethanol/toluene solvent system gave 22.90 g (43%) and had Rf 0.69 on silica TLC with ethyl acetate; mp 135.8°-137.2° C. Anal. Calcd. for C10H10BrNO2 : C, 46.90; H, 3.94; N, 5.47; Br, 31.20. Found: C, 47.13; H, 4.00; N, 5.46; Br, 31.31.

1. additionThe temperature rose to 80° C. during the addition
2. temperaturethe solution was then refluxed 20 minutes
3. customAn immediate precipitation
4. filtrationThe tan-white crystals were filtered
5. washwashed with three 100 ml portions of 1:1 toluene/petroleum ether
6. customcrystallisation
7. additioninduced by addition of toluene to the ethanolic solution
8. customThree crops of crystals from the ethanol/toluene solvent system gave 22.90 g (43%)