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

Participants

Reaction Steps

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%.

Provenance & Evidence