Reacción #56549

Ecuación de reacción

retinal

hydrochloric acid

→

beta-carotene

Rendimiento 20.0%

Disolventes

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter refluxing for two hours
2. 2
   Extracciónextracted several times with ether
3. 3
   Lavadowashed with saturated aqueous sodium chloride solution, dried sulfate
4. 4
   Concentraciónconcentrated by solvent removal at the rotary evaporator
5. 5
   OtroThe residue was purified by chromatography over silica gel
6. 6
   LavadoElution with hexane

Procedimiento

A slurry of titanium trichloride (770 mg, 5.0 mmol) in 20 ml dry tetrahydrofuran was prepared under an inert atmosphere (nitrogen or argon), and magnesium turnings (120 mg, 5.0 mmol) were added. The resulting mixture was refluxed overnight to form the Ti(II) reagent, and a solution of retinal (710 mg, 2.5 mmol) in 5 ml dry tetrahydrofuran was added. After refluxing for two hours, the solution was poured into 50 ml 2 N aqueous hydrochloric acid and extracted several times with ether. The ether extracts were combined, washed with saturated aqueous sodium chloride solution, dried sulfate, and concentrated by solvent removal at the rotary evaporator. The residue was purified by chromatography over silica gel. Elution with hexane gave 130 mg (20% yield) beta-carotene identified by thin-layer chromatographic comparison with an authentic sample, and by its characteristic ultraviolet spectrum.

Fuente