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.

中文翻译：

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方便地从吲哚制备3,3-二溴-1,3-二氢吲哚-2-酮和吲哚-2,3-二酮（靛红）

3，3-二溴-1，3-二氢吲哚-2-酮，吲哚-2，3-二酮的有用前体，很容易通过3-溴吲哚或吲哚与2或3摩尔当量的反应而形成。的Ñ溴代琥珀酰亚胺，分别在含水叔丁醇。6元环可能会发生某些溴化反应，而3,5,6-三溴吲哚-4,7-二酮是3-溴-4,7-二甲氧基-吲哚的产物。与吲哚-3-甲醛和1 H-吡咯并[2,3- b ]吡啶的类似反应得到3,3-二溴-1,3-二氢吲哚-2-一和3,3-二溴-1 H-吡咯并[2 ，3 - b ]吡啶-2-酮类似物，后者仅难于产生相应的2，3-二酮。