反応 #56554

反応方程式

Lithium Borohydride

retinal

hydrochloric acid

→

beta-carotene

収率 60.0%

溶媒

tetrahydrofuran

反応条件

後処理

1. 1
   その他A solution was prepared
2. 2
   温度the reaction was refluxed for four hours
3. 3
   抽出was extracted several times with ether
4. 4
   洗浄washed with saturated aqueous sodium chloride solution
5. 5
   乾燥dried over magnesium sulfate
6. 6
   濃縮concentrated by solvent removal at the rotary evaporator
7. 7
   その他The residue was further purified by chromatography on silica gel
8. 8
   洗浄Elution with hexane

実験手順

A solution was prepared by dissolving titanium tetrachloride (1.10 ml, 10.0 mmol) in 25 ml dry tetrahydrofuran under an inert atmosphere. Lithium Borohydride (110 mg, 5.0 mmol) was added, and the resulting solution was stirred at 50° for two hours. A solution of retinal (1.42 gm, 5.0 mmol) 5 ml dry tetrahydrofuran was added, and the reaction was refluxed for four hours. After this, the solution was poured into 50 ml 2 N aqueous hydrochloric acid, and was extracted several times with ether. 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 further purified by chromatography on silica gel. Elution with hexane gave 0.8 gm (60%) beta-carotene, identified by comparison with an authentic sample; mp 180°-182°.

出典