Hydrochloric Acid → Beta-Carotene

HRID 28276

Reaction equation

HRID 28276 reaction equation
[BH4-].[Li+].[CH3:3][C:4]1[CH2:9][CH2:8][CH2:7][C:6]([CH3:11])([CH3:10])[C:5]=1/[CH:12]=[CH:13]/[C:14](/[CH3:23])=[CH:15]/[CH:16]=[CH:17]/[C:18](/[CH3:22])=[CH:19]/[CH:20]=O.Cl>O1CCCC1.[Ti](Cl)(Cl)(Cl)Cl>[CH3:3][C:4]1[CH2:9][CH2:8][CH2:7][C:6]([CH3:11])([CH3:10])[C:5]=1/[CH:12]=[CH:13]/[C:14](/[CH3:23])=[CH:15]/[CH:16]=[CH:17]/[C:18](/[CH3:22])=[CH:19]/[CH:20]=[CH:20]/[CH:19]=[C:18](\[CH3:22])/[CH:17]=[CH:16]/[CH:15]=[C:14](\[CH3:23])/[CH:13]=[CH:12]/[C:5]1[C:6]([CH3:11])([CH3:10])[CH2:7][CH2:8][CH2:9][C:4]=1[CH3:3]

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 638015RetinalHCID 4148881Lithium borohydride

Product 1

HCID 5280489Beta-CaroteneYield 60%

Reagents, catalysts & solvents 2

HCID 24193Titanium TetrachlorideCatalystHCID 8028TetrahydrofuranSolvent

Procedure

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°.

Workup

  1. customA solution was prepared
  2. temperaturethe reaction was refluxed for four hours
  3. extractionwas extracted several times with ether
  4. washwashed with saturated aqueous sodium chloride solution
  5. dry with materialdried over magnesium sulfate
  6. concentrationconcentrated by solvent removal at the rotary evaporator
  7. customThe residue was further purified by chromatography on silica gel
  8. washElution with hexane

Sources & evidence

ORD record
ord-a2a98f01d03845299abd3c969e826119
Source dataset
uspto-grants-1980_09
Patent number
US04225734

Linked notes

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