Benzaldehyde → 3,4-dihydro-4,4-dimethyl-6-[(E)-alpha-methylstyryl]-2H-1-benzopyran

HRID 37433Notes

Reaction equation

HRID 37433 reaction equation
[Br-].[CH3:2][C:3]1([CH3:34])[C:12]2[C:7](=[CH:8][CH:9]=[C:10]([CH:13]([P+](C3C=CC=CC=3)(C3C=CC=CC=3)C3C=CC=CC=3)[CH3:14])[CH:11]=2)[O:6][CH2:5][CH2:4]1.[CH:35](=O)[C:36]1[CH:41]=[CH:40][CH:39]=[CH:38][CH:37]=1.CO.O>C1OCCC1>[CH3:34][C:3]1([CH3:2])[C:12]2[CH:11]=[C:10](/[C:13](/[CH3:14])=[CH:35]/[C:36]3[CH:41]=[CH:40][CH:39]=[CH:38][CH:37]=3)[CH:9]=[CH:8][C:7]=2[O:6][CH2:5][CH2:4]1

Participants

5

Reactant 3

HCID 240BenzaldehydeHCID 199355281-(4,4-Dimethyl-6-chromanyl)ethyltriphenylphosphonium bromideHCID 22242641Methanol--water (1/1)

Product 1

HCID 675909203,4-dihydro-4,4-dimethyl-6-[(E)-alpha-methylstyryl]-2H-1-benzopyranYield 19.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

16.5 g of [1-(4,4-dimethyl-6-chromanyl)ethyl]triphenylphosphonium bromide and 3 g of benzaldehyde were heated under reflux in 100 ml of butylene oxide for 20 hours. The reaction mixture obtained was poured into a methanol/water mixture (6:4) and extracted with hexane. After drying and evaporating the organic phase the crude product was chromatographed (silica gel, eluting agent hexane) and recrystallized from hexane. There were obtained 1.5 g of 3,4-dihydro-4,4-dimethyl-6-[(E)-α-methylstyryl]-2H-1-benzopyran in the form of colorless crystals, melting point 64°-65° C.

Workup

  1. customThe reaction mixture obtained
  2. extractionextracted with hexane
  3. customAfter drying
  4. customevaporating the organic phase the crude product
  5. customwas chromatographed
  6. wash(silica gel, eluting agent hexane)
  7. customrecrystallized from hexane

Sources & evidence

ORD record
ord-762b6129cf304a38a841057a34be1004
Source dataset
uspto-grants-1995_05
Patent number
US05420273

Reaction notes

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