反应详情

There is added to a solution of 2-trimethylsilyl-1,3-dithiane (16.2 g ) in dry tetrahydrofuran (170 ml) at -65° a 1.9M solution of n-butyllithium in hexane (45 ml). The reaction mixture is progressively warmed to 0° in the course of 31/2 hours and cooled to -65°. A solution of 4-dimethylamino-benzophenone (19.2 g) in dry tetrahydrofuran (100 ml) is than slowly added. The reaction mixture is progressively warmed to room temperature overnight and poured into a mixture of water (1000 ml ) and dichloromethane (200 ml). After separation of the layers, the aqueous solution is extracted with dichloromethane (3×200 ml). The combined organic solutions are washed with water (100 ml) and dried over magnesium sulphate. The solvents are evaporated in vacuo and the residue is recrystallised from ethyl acetate. The product is dried in vacuo to constant weight to yield (4-dimethylaminophenyl)(1,3-dithian-2-ylidene)-phenylmethane, m.p. 172°-174°.

1. temperaturecooled to -65°
2. additionthan slowly added
3. customAfter separation of the layers
4. extractionthe aqueous solution is extracted with dichloromethane (3×200 ml)
5. washThe combined organic solutions are washed with water (100 ml)
6. dry with materialdried over magnesium sulphate
7. customThe solvents are evaporated in vacuo
8. customthe residue is recrystallised from ethyl acetate
9. customThe product is dried in vacuo to constant weight