反応 #56547

反応方程式

retinal

hydrochloric acid

→

beta-carotene

収率 85.0%

溶媒

tetrahydrofuran

反応条件

後処理

1. 1
   抽出The solution was extracted several times with ether
2. 2
   洗浄washed with saturated aqueous sodium chloride solution
3. 3
   乾燥dried over magnesium sulfate
4. 4
   濃縮concentrated by solvent removal at the rotary evaporator
5. 5
   その他The residue was purified by chromatography on silica gel
6. 6
   洗浄Elution with hexane

実験手順

A slurry of titanium trichloride (1.54 gm, 10.0 mmol) in 30 ml dry tetrahydrofuran was prepared under an inert atmosphere (nitrogen or argon), and powdered lithium aluminum hydride (190 mg. 5.0 mmol) was cautiously added. The resulting solution was stirred for two hours at room temperature to form the Ti(II) reagent, and a solution of retinal (1.42 gm, 5.0 mmol) in 5 ml dry tetrahydrofuran was added. The solution was stirred a further fifteen hours at room temperature, and then poured into 50 ml 2 N aqueous hydrochloric acid. The solution was extracted several times with ether, and the ether extracts were combined, washed with saturated aqueous sodium chloride solution, dried over magnesium sulfate, and concentrated by solvent removal at the rotary evaporator. The residue was purified by chromatography on silica gel. Elution with hexane gave 1.14 gm (85% yield) beta-carotene which was identified by thin-layer chromatographic comparison with an authentic sample, by its characteristic ultraviolet spectrum, and by its melting point: mp 180°-182°.

出典