Synthesis and crystal structure of a bench-stable pyridinium ketene hemiaminal: 1-(1-eth­oxy­ethen­yl)-2-[meth­yl(phen­yl)amino]­pyridin-1-ium tri­fluoro­methane­sulfonate

The novel bench-stable N-quaternized ketene N,O-acetal, C(16)H(19)N(2)O(+)·CF(3)O(3)S(−), was synthesized and its structure determined. The title compound is a rare example of a pyridinium ketene hemiaminal for which a crystal structure has been determined, joining the 2-chloro-1-(1-ethyoxyethen­yl)pyridin-1-ium tri­fluoro­methane­sulfonate salt from which it was synthesized. The cationic species of the title compound can be defined by three individually planar fragments assembling into a non-coplanar cation. The phenyl substituent extending from the amino nitro­gen atom and the ethyoxyvinyl substituent extending from the pyridine N atom are oriented on the same side of the mol­ecule and maintain the closest coplanar relationship of the three fragments. Supra­molecular inter­actions are dominated by C—H⋯O inter­actions from the cation to the SO(3) side of the tri­fluoro­methane­sulfonate anion, forming a two-dimensional substructure.