| Popis: |
3,3-Dibromo-1,3-dihydroindol-2-ones, useful precursors of Indole-2,3-diones, are readily formed by the reaction of either 3-bromoindoles or indoles with 2 or 3 mol equiv. of N-bromosuccinimide, respectively, in aqueous t-butyl alcohol. Some bromination of the 6-membered ring may occur and 3,5,6-tribromoindole-4,7-dione is a product from 3-bromo-4,7-dimethoxy-Indole. Similar reactions with Indole-3-carbaldehyde and 1H-pyrrolo[2,3-b]pyridine give 3,3-dibromo-1,3-dihydroindole-2-one and 3,3-dibromo-1H-pyrrolo[2,3-b]pyridin-2-one analogue, respectively, the latter yielding the corresponding 2,3-dione only with difficulty. |
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