3-Methyl-2-butenal → 7-Ethoxy-2,2,8-trimethyl-2H-1-benzopyran

HRID 986844Notes

Reaction equation

HRID 986844 reaction equation
[CH3:1][C:2]1[C:7]([O:8][CH2:9][CH3:10])=[CH:6][CH:5]=[CH:4][C:3]=1[OH:11].[CH3:12][C:13]([CH3:17])=[CH:14][CH:15]=O>C1(C)C=CC=CC=1.[Cl-].[NH4+].[O-]CC.[O-]CC.[O-]CC.[O-]CC.[Ti+4]>[CH2:9]([O:8][C:7]1[C:2]([CH3:1])=[C:3]2[C:4]([CH:15]=[CH:14][C:13]([CH3:17])([CH3:12])[O:11]2)=[CH:5][CH:6]=1)[CH3:10]

Participants

6

Reactant 2

HCID 610203-Methyl-2-butenalHCID 20156628HCID 20156628, compound

Product 1

HCID 1797797-Ethoxy-2,2,8-trimethyl-2H-1-benzopyranYield 50%

Reagents, catalysts & solvents 3

HCID 76524Titanium tetraethoxideCatalystHCID 1140TolueneSolvent3×HCID 25517Ammonium ChlorideSolvent

Procedure

To a solution of 5.7 g (25 millimoles) of titanium tetraethoxide in 50 ml of toluene a solution of 13.8 g (100 millimoles) of 2-methyl-3-ethoxy-phenol and 50 ml of toluene is added at 20° C. under nitrogen. The orangered solution is heated to boiling for an hour, and subjected to slow distillation until the ethanol is removed. The mixture is cooled to room temperature and a mixture of 10.6 g (150 millimoles) of dimethyl acroleine and 200 ml of toluene is added dropwise. The reaction mixture is heated to boiling for 8 hours, diluted with a saturated ammonium chloride solution and extracted with ether. The solvent is removed and the residue purified as described in Example 3. This 10.2 g of the desired compound are obtained in the form of a colorless oil, yield 50%.

Workup

  1. temperatureThe orangered solution is heated
  2. waitto boiling for an hour
  3. distillationdistillation until the ethanol
  4. customis removed
  5. additionis added dropwise
  6. temperatureThe reaction mixture is heated
  7. extractionextracted with ether
  8. customThe solvent is removed
  9. customthe residue purified

Sources & evidence

ORD record
ord-6c3b8ed6d31d4eaa9826e9422bae0355
Source dataset
uspto-grants-1987_12
Patent number
US04716238

Reaction notes

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