反应详情

6-(3-Methoxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (3.5 g) (see Preparation 6) was dissolved in dry 2,4,6-collidine (15 ml), anhydrous lithium iodide (3 g) was added and the mixture was heated under reflux under a nitrogen atmosphere for 24 hours. After cooling, the mixture was taken up in dichloromethane and washed with 2N aqueous hydrochloric acid solution (×3). The organic layer was dried (anhydrous sodium sulphate), the solvent removed under reduced pressure and the residue chromatographed on silica eluting with a solvent gradient of 1:1 hexane: dichloromethane changing to dichloromethane to yield 6-(3-hydroxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (2.25 g) as an oil.

1. temperaturethe mixture was heated
2. temperatureunder reflux under a nitrogen atmosphere for 24 hours
3. temperatureAfter cooling
4. washwashed with 2N aqueous hydrochloric acid solution (×3)
5. dry with materialThe organic layer was dried (anhydrous sodium sulphate)
6. customthe solvent removed under reduced pressure
7. customthe residue chromatographed on silica eluting with a solvent gradient of 1:1 hexane