Amidine Dications as Superelectrophiles.
J AM CHEM SOC
17980 - 17985.
2-Dimethylalkylammonium pyridinium and 2-dimethylalkylammonium pyrimidinium ditriflate salts are very powerful methylating agents toward phosphorus (triphenylphosphine) and nitrogen (triethylamine) nucleophiles. In competition experiments with triethylamine as nucleophile, these N-methyl disalts are more reactive methylating agents than dimethyl sulfate. Reaction of the pyridinium dications with water as an oxygen nucleophile leads to attack at the 2-position of the heteroaromatic ring and displacement of an ammonium group; 2-hydroxypyridinium compounds are formed in the first instance, which are easily converted to 2-pyridones. Extending the scope of the reactions, a tricationic 2,6-bis(dimethylalkylammonium)pyridinium salt has also been prepared and characterized and its reactivity as a methylating agent assessed in comparison with that of the dications.
|Title:||Amidine Dications as Superelectrophiles|
|Keywords:||SUPER-ELECTRON-DONOR, FREE-RADICAL SUBSTITUTION, CLUSTER-FREE HYDROGENASE, ACTIVE-SITE MODELS, DIQUATERNARY SALTS, CRYSTAL-STRUCTURE, TRIPLE RESONANCE, TERTIARY AMIDES, METHANOGENIC ARCHAEA, PYRIDINE-DERIVATIVES|
|UCL classification:||UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Maths and Physical Sciences
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