反应详情

温度

75 °C

A mixture of 2,6-dichloro-2',3',4'-trimethoxy-6'-methyl-benzophenone (1.78 g; 5 mmol) hydrobromic acid (7.5 ml; 30% in acetic acid) and acetic acid (7.5 ml) is stirred at 75° C. for 2 hours. Water is added and the mixture extracted with methylenechloride. The extract is washed with waterand shaken with 2N sodium hydroxide. The alcaline solution is acidified with hydrochloric acid, the separated compound dissolved in methylenechloride and the solution washed with water. After evaporation ofthe solvent purification is carried out by chromatography (flash column, filled with 36 g of silicagel; elution with 500 ml of petrolether/ethylacetate (4:1; v/v) and 250 ml of petrolether/ethylacetate(1:1; v/v)). the fraction containing the compound is concentrated, the compound crystallized. The yellow crystals are washed with petrolether andsucked off; 0.64 g (39% y), mp. 182° C.

1. extractionthe mixture extracted with methylenechloride
2. washThe extract is washed with waterand
3. stirringshaken with 2N sodium hydroxide
4. dissolutionthe separated compound dissolved in methylenechloride
5. washthe solution washed with water
6. customAfter evaporation ofthe solvent purification
7. additionis carried out by chromatography (flash column, filled with 36 g of silicagel; elution with 500 ml of petrolether/ethylacetate (4:1; v/v) and 250 ml of petrolether/ethylacetate(1:1; v/v))
8. additionthe fraction containing the compound
9. concentrationis concentrated
10. customthe compound crystallized
11. washThe yellow crystals are washed with petrolether