Reacción #56554

Ecuación de reacción

Lithium Borohydride

retinal

hydrochloric acid

→

beta-carotene

Rendimiento 60.0%

Disolventes

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroA solution was prepared
2. 2
   Temperaturathe reaction was refluxed for four hours
3. 3
   Extracciónwas extracted several times with ether
4. 4
   Lavadowashed with saturated aqueous sodium chloride solution
5. 5
   Secadodried over magnesium sulfate
6. 6
   Concentraciónconcentrated by solvent removal at the rotary evaporator
7. 7
   OtroThe residue was further purified by chromatography on silica gel
8. 8
   LavadoElution with hexane

Procedimiento

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°.

Fuente