反应详情

温度

10 °C

Into a 3 l. 3-necked r.b. flask equipped with a mechanical stirrer, thermometer, dropping funnel, and nitrogen gas inlet was placed 24 g. (0.5 mole) of 50% NaH prewashed with hexane, and 1000 ml. of dry tetrahydrofuran. 65 g. (0.5 mole) of ethyl acetoacetate was then added dropwise at -10° to 0° C. using a dry ice-acetone bath. After addition of ethyl acetoacetate was finished, the mixture was gradually warmed up to 10° C. in the course of 15 minutes and then 240 ml. (0.528 mole) of 2.2M n-butyllithium was added dropwise maintaining temperature below -40° to -20° C. After the mixture was stirred at -10° for 15 minutes, 100.5 g. (0.5 mole) of 4-methoxybenzyl bromide was added dropwise over a period of 45 minutes at -10° C. The reaction mixture was gradually warmed up to room temperature and stirred for an additional hour, and then cooled to -20° C. 5N HCl was then carefully added until the solution was slightly acidic.

1. customflask equipped with a mechanical stirrer
2. temperaturemaintaining temperature below -40° to -20° C
3. temperatureThe reaction mixture was gradually warmed up to room temperature
4. stirringstirred for an additional hour
5. temperaturecooled to -20° C