Hydrochloric Acid → 5-bromo-2-methyl-3-(piperidin-4-ylthio)-1H-indole

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Reaction Steps

4-Bromophenylhydrazine hydrochloride (11.5 g) is solubilized in a solution of 1,1-dimethylethyl 4-[(2-oxopropyl)thio]piperidine-1-carboxylate (14 g, prepared in Example 11) in isopropanol (100 ml) under nitrogen. The solution is cooled to 0° C. and saturated with gaseous hydrogen chloride. After 4 hours at room temperature, the precipitate is filtered off, taken up in sodium hydroxide and extracted with ether and then with methylene chloride. The organic phases are combined, dried over sodium sulfate and concentrated. The solid obtained is taken up in the minimum amount of ether and recrystallized from xylene to give 5-bromo-2-methyl-3-(piperidin-4-ylthio)-1H-indole (9.5 g).

Provenance & Evidence