反应详情

A solution of 11.6 g of bromine in 28 ml of carbon tetrachloride is added dropwise over the course of 35 minutes to a suspension of 10.0 g of 2-[2'-(1H-tetrazol-5-yl)-phenyl]-5-methylbenzofuran in 418 ml of dioxane. After stirring for 3 hours at room temperature, 12.6 ml of cyclohexene are added dropwise and then the reaction mixture is concentrated by evaporation in vacuo. The residue is taken up in 50 ml of 2N sodium hydroxide solution and extracted with 100 ml of ether. Three clear phases form. The two lower phases are separated off, acidified with 40 ml of 4N hydrochloric acid and extracted three times with 100 ml of ethyl acetate each time. The combined ethyl acetate phases are washed with 100 ml of brine and, after removal of the solvent in vacuo, they result in a yellow oil which yields crystalline 3-bromo-2-[2'-(1H-tetrazol-5-yl)-phenyl]-5-methylbenzofuran, m.p. 167-168°, from toluene.

1. concentrationthe reaction mixture is concentrated by evaporation in vacuo
2. extractionextracted with 100 ml of ether
3. customThe two lower phases are separated off
4. extractionextracted three times with 100 ml of ethyl acetate each time
5. washThe combined ethyl acetate phases are washed with 100 ml of brine
6. customafter removal of the solvent in vacuo, they
7. customresult in a yellow oil which