تفاعل #56554

معادلة التفاعل

Lithium Borohydride

retinal

hydrochloric acid

→

beta-carotene

المردود 60.0%

المذيبات

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   أخرىA solution was prepared
2. 2
   درجة الحرارةthe reaction was refluxed for four hours
3. 3
   استخلاصwas extracted several times with ether
4. 4
   غسيلwashed with saturated aqueous sodium chloride solution
5. 5
   تجفيفdried over magnesium sulfate
6. 6
   تركيزconcentrated by solvent removal at the rotary evaporator
7. 7
   أخرىThe residue was further purified by chromatography on silica gel
8. 8
   غسيلElution with hexane

الإجراء التجريبي

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°.

المصدر