| 摘要 |
6-Bromo-or 4 : 6-dibromo-2-hydroxynaphthalene is prepared by heating 1 : 6-dibromo- or 1 : 4 : 6-tribromo-2-hydroxynaphthalene or an alkali metal salt of either of these compounds with an alkali metal sulphite, for example in an aqueous or aqueous-alcoholic solution. In examples: (1) 1 : 6-dibromo-2-hydroxynaphthalene is boiled with methyl or ethyl alcohol, potassium sulphite and water and after the alcohol has been distilled off the 6-bromo-2-hydroxynaphthalene is separated; sodium sulphite may replace potassium sulphite and the sodium salt of 1 : 6-dibromo-2-hydroxynaphthalene may be used; (2) 1 : 4 : 6 : tribromo-2-hydroxynaphthalene is boiled with alcohol, water and potassium sulphite to yield 4 : 6-dibromo-2-hydroxynaphthalene.
|
