Synthetic approaches to fluorinated derivatives of 4-(vinylthio)pyridine

Abstract

An effective strategy for the synthesis of new polyfluoropyridine derivatives, which are valuable building blocks in the synthesis of potentially biologically active fluorine-containing compounds, has been developed. A series of fluorinated derivatives of 4-(vinylthio)pyridine have been synthesized, starting from pentafluoropyridine and 2-mercaptoethanol via aromatic nucleophilic substitution of fluorine atoms and elimination process. The obtained derivatives with NHAlk-substituents at position 2-, are of interest as new heteroaryl vinyl sulfide components that can be used in the synthesis of more complex fluorine-containing structures. The possibility of oxidation of tetrafluoro-4-(vinylthio)pyridine to the corresponding heteroaryl vinyl sulfone has been demonstrated. It was found that the resulting tetrafluoro-4-(vinylsulfonyl)pyridine reacted with cycloheptanamine under basic conditions to form a heterocyclic framework containing fragments of pyridine and 3,4-dihydro-2H-1,4-thiazine 1,1-dioxide.