Réaction #56555

Équation de réaction

Calcium hydride

retinal

hydrochloric acid

→

beta-carotene

Rendement 75.0%

Solvants

tetrahydrofuran

tetrahydrofuran

Conditions de réaction

Traitement

1. 1
   AutreA solution was prepared
2. 2
   Températurethe reaction was refluxed for three hours
3. 3
   Extractionwas extracted several times with ether
4. 4
   Lavagewashed with saturated aqueous sodium chloride solution
5. 5
   Séchagedried over magnesium sulfate
6. 6
   Concentrationconcentrated by solvent removal at the rotary evaporator
7. 7
   AutreThe residue was further purified by chromatography on silica gel
8. 8
   LavageElution with hexane

Mode opératoire

A solution was prepared by dissolving titanium tetrachloride (1.10 ml, 10.0 mmol) in 25 ml tetrahydrofuran under an inert atmosphere. Calcium hydride (420 mg, 10.0 mmol) was added, and the resulting solution was stirred for two hours at room temperature. A solution of retinal, (1.42 gm, 5.0 mmol) in 5 ml dry tetrahydrofuran was then added, and the reaction was refluxed for three 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 1.0 gm (75%) beta-carotene, identified by thin-layer chromatographic comparison with an authentic sample, and by its melting point, mp 180°-182°.

Source