تفاعل #56547

معادلة التفاعل

retinal

hydrochloric acid

→

beta-carotene

المردود 85.0%

المذيبات

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   استخلاصThe solution was extracted several times with ether
2. 2
   غسيلwashed with saturated aqueous sodium chloride solution
3. 3
   تجفيفdried over magnesium sulfate
4. 4
   تركيزconcentrated by solvent removal at the rotary evaporator
5. 5
   أخرىThe residue was purified by chromatography on silica gel
6. 6
   غسيلElution with hexane

الإجراء التجريبي

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°.

المصدر