Synthesis of trifluoromethylated azines via nucleophilic oxidative substitution of hydrogen by trifluoromethyl carbanions.
A novel, three-step method of trifluoromethylation of azines via oxidative nucleophilic substitution of hydrogen in the heteroaromatic ring by a CF3- carbanion is presented. The key reaction of this process is the addition of the CF3- carbanion, generated by treatment of Me3SiCF3 with KF(s) and Ph3SnF catalyst, to N-alkylazinium salts. The resulting dihydroazines containing a trifluoromethyl group are relatively stable compounds and can be isolated in a pure form. Deprotection of the N-p-methoxybenzyl substituent and aromatization of the heterocyclic ring upon treatment with CAN provides azines with a CF3 group in the ring position originally occupied by hydrogen. The whole process can be thus considered as a nucleophilic oxidative displacement of hydrogen by a CF3- carbanion.
Loska
Rafał
R
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw 42, Poland.
Majcher
Monika
M
Makosza
Mieczysław
M
D000838:Anions; D006834:Hydrazines / Q000138:chemical synthesis* / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization
D000838:Anions; D006834:Hydrazines; D006859:Hydrogen