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

Participants

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 such that the internal temperature was kept at 3-8° C. (about 1 h). Subsequently, the mixture was stirred without external cooling for 1 h and allowed to warm to room temperature. 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 concentrated under reduced pressure. About 700 g of a red-brown crystalline mass were obtained and were dissolved in n-heptane (600 ml) at 60° C. and then crystallized in a refrigerator at 4° C. Filtration with suction gave 590 g (85%) of 4-amino-3-bromophenylsulfur pentafluoride as brownish crystals, m.p. 59-59.5° C.

Provenance & Evidence