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Pyrazine Radical Cations as a Catalyst for the Aerobic Oxidation of Amines
Author(s) -
Brisar Rok,
Hollmann Dirk,
Mejia Esteban
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201700949
Subject(s) - chemistry , electron paramagnetic resonance , catalysis , reagent , pyrazine , radical ion , solvent , green chemistry , photochemistry , tetramethylpyrazine , organic chemistry , combinatorial chemistry , inorganic chemistry , reaction mechanism , ion , medicine , physics , alternative medicine , nuclear magnetic resonance , pathology
An efficient and green synthetic method for the preparation of N , N ‐disubstituted tetramethylpyrazinium radical cations was developed, which does not require any solvent or strong alkylating agents. The investigation by UV/Vis and electron paramagnetic resonance (EPR) spectroscopy proved the stability of the prepared radical cation. Moreover, it was shown for the first time that the prepared N , N ‐disubstituted tetramethylpyrazine can act as a powerful metal‐free catalyst for the selective oxidative homocoupling of amines to the corresponding imines under solvent‐free conditions. Furthermore, oxygen or even air can be employed as an efficient oxidative reagent.