Heterocycles in organic synthesis. Part 17. Conversion of primary amines into bromides and chlorides

Abstract

Primary alkyl, benzyl, and heteroarylamines are converted both by pentaphenyl- and 2,4,6-triphenyl-pyrylium bromides into the corresponding pyridinium bromides. Pyrolysis of the triphenyl derivatives affords a convenient synthesis of alkyl and benzyl bromides. Alkyl and benzyl chlorides are prepared from the corresponding amines via the 2,4,6-triphenylpyridinium tetrafluoroborates by pyrolysis with a KCl–NaCl–ZnCl₂ eutectic.