ABSTRACT
New fluorinated 3,6-dihydropyridines were obtained by the electrophilic fluorination of 1,2-dihydropyridines with Selectfluor®. These 3-fluoro-3,6-dihydropyridines were easily converted to corresponding pyridines by the elimination of hydrogen fluoride under mild conditions. A new approach to the synthesis of methyl 2-(fluoromethyl)-5-nitro-6-arylnicotinates by the fluorination of 3-fluoro-2-methyl-5-nitro-3,6-dihydropyridines or 1,2-dihydropyridines with Selectfluor® has been developed.
Subject(s)
Dihydropyridines/chemistry , Fluorine/chemistry , Halogenation , Hydrocarbons, Fluorinated , Hydrocarbons, Fluorinated/chemical synthesis , Hydrocarbons, Fluorinated/chemistryABSTRACT
The synthesis of trifluoromethylthiolated ketenimines is herein described. They are easily synthesized from the corresponding α-trifluoromethylthiolated oximes upon activation with triflic anhydride and a base. The presumed nitrilium ion resulting from the Beckmann rearrangement is deprotonated to lead to the key intermediate, whose stability brought by the fluorinated substituent was unforeseeable. The reaction of these new building blocks with a variety of nucleophiles affords a vast array of cyclic and acyclic products bearing the valuable SCF3 moiety.
