Chlorosulfonic acid → N-methanesulfonyl-5-chlorosulfonyl-2-aminobenzimidazole

Beteiligte Stoffe

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Reaktionsschritte

To 9.5 mL (20 eq., 142 mmol) of well stirred chlorosulfonic acid at ˜25° C. was added N-methanesulfonyl-2-aminobenzimidazole (1.5 g, 7.1 mmol) in small portions over 10 minutes with slight exotherming. The solution was stirred at ˜25° C. for 3.5 hours, then was added dropwise to a well stirred mixture of ice and water. The aqueous solution was slowly basified to pH ˜7.5 with solid sodium bicarbonate and extracted with EtOAc. A precipitate formed in the organic phase which was filtered off and was washed with H2O and dried on the filter to yield 1.23 g of N-methanesulfonyl-5-chlorosulfonyl-2-aminobenzimidazole. HPLC, single peak, ret. time=7.61 min. MS: Obs. M+H @ 310.0 amu.

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