1,3-Dibromo-5,5-dimethylhydantoin → 2-Bromo-4-(pentafluoro-lambda~6~-sulfanyl)aniline

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Reaction Conditions

Reaction Steps

4-Aminophenylsulfur pentafluoride (510 g. 2.327 mol) was dissolved in dichloromethane (7 l), the solution was cooled to 5° C. and, while stirring, 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione (326 g. 1.14 mol) was introduced in several portions with ice cooling so that the internal temperature was kept at 3-8° C. (approx. 1 h). The mixture was then left to stir and warm to room temperature without external cooling for 1 h. The mixture was filtered through a bed of silica gel (volume about 1 l) and washed with dichloromethane (5.5 l), and the filtrate was evaporated in vacuo. About 700 g of a red-brown crystalline mass was obtained and was dissolved in n-heptane (600 ml) at 60° C. and then crystallized in a refrigerator at 4° C. Filtration with suction resulted in 590 g (85%) of 4-amino-3-bromphenylsulfur pentafluoride as brownish crystals, m.p. 59-59.5° C.

Provenance & Evidence