反応 #56549

反応方程式

retinal

hydrochloric acid

→

beta-carotene

収率 20.0%

溶媒

tetrahydrofuran

反応条件

後処理

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

実験手順

A slurry of titanium trichloride (770 mg, 5.0 mmol) in 20 ml dry tetrahydrofuran was prepared under an inert atmosphere (nitrogen or argon), and magnesium turnings (120 mg, 5.0 mmol) were added. The resulting mixture was refluxed overnight to form the Ti(II) reagent, and a solution of retinal (710 mg, 2.5 mmol) in 5 ml dry tetrahydrofuran was added. After refluxing for two hours, the solution was poured into 50 ml 2 N aqueous hydrochloric acid and extracted several times with ether. The ether extracts were combined, washed with saturated aqueous sodium chloride solution, dried sulfate, and concentrated by solvent removal at the rotary evaporator. The residue was purified by chromatography over silica gel. Elution with hexane gave 130 mg (20% yield) beta-carotene identified by thin-layer chromatographic comparison with an authentic sample, and by its characteristic ultraviolet spectrum.

出典