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(1S,2S,5R)-2-isopropyl-5-methylcyclohexyl 4-nitrobenzoate

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发表于 2010-11-27 23:57 | 显示全部楼层 |阅读模式
实例分享
【合成反应标题】: Mitsunobu 法醇的构型翻转合成方法
【反应scheme】:
【来源】: 文献
【反应类型】: 烃化
【文献出处】: Organic Syntheses, Coll. Vol. 9, p.607; Vol. 73, p.110.
【详细描述】: Mitsunobu 法醇的构型翻转合成方法
【是否验证】:
A 250-mL, three-necked, round-bottomed flask is equipped with a stirring bar, nitrogen inlet, rubber septum, and thermometer. The flask is charged with 3.00 g of (1R, 2S,5R)-(−)-menthol (19.2 mmol), 12.9 g of 4-nitrobenzoic acid (77.2 mmol), 20.1 g of triphenylphosphine (PPh3) (76.6 mmol), and 150 mL of tetrahydrofuran. The flask is immersed in an ice bath, and 12.1 mL of diethyl azodicarboxylate (77 mmol) is added dropwise at a rate such that the temperature of the reaction mixture is maintained below 10°C. Upon completion of the addition, the flask is removed from the ice bath and the solution is allowed to stir at room temperature overnight (14 hr) and subsequently at 40°C for 3 hr. The reaction mixture is cooled to room temperature, diluted with 150 mL of ether, and washed twice with 100 mL portions of saturated aqueous sodium bicarbonate solution. The aqueous layers are combined and back-extracted with 100 mL of ether. The combined organic layers are dried over sodium sulfate. Excess solvent and other volatile reaction components are completely removed under reduced pressure initially on a rotary evaporator and then under high vacuum (approximately 0.2 mm for 3 hr at 30°C). The resulting semi-solid is suspended in 40 mL of ether and the suspension is allowed to stand at room temperature overnight. The mixture is stirred while 20 mL of hexanes is slowly added. The resulting white solid is filtered under vacuum and the filter cake is washed with 200 mL of 50% (v/v) ether-hexanes. The solvent is removed from the filtrate on a rotary evaporator under reduced pressure to give a yellow oil that is dissolved in 10 mL of methylene chloride and diluted with 40 mL of 8% ether-hexanes. The solution is applied to a flash chromatography column and eluted with 8% ether-hexanes to give 5.03 g (85.6%) of pure nitrobenzoate ester as a white crystalline solid.

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发表于 2012-1-1 17:25 | 显示全部楼层
谢谢分享,这么经典的反应怎么没人顶啊
发表于 2012-2-7 16:39 | 显示全部楼层
经典,顶
发表于 2012-2-10 14:40 | 显示全部楼层
顶!
发表于 2012-3-23 23:31 | 显示全部楼层
我来学些下,顶。
发表于 2012-3-28 16:17 | 显示全部楼层
顶下
发表于 2012-3-28 16:18 | 显示全部楼层
英文版的看的不太懂
发表于 2012-3-28 16:18 | 显示全部楼层
这个反应出自哪里,文献?
发表于 2014-7-8 19:18 | 显示全部楼层
顶,正好有用
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