Preparation and N-Oxidation of some analogues of poly (2-vinylpyridine)

Analogues of vinylpyridine monomers: 2-(2-pyridyl)-2-butene (I), 2-(2-pyridyl)-1-propene (II), and 1-(2-Pyridyl)-1-propene (III) were prepared and their polymerization was attempted. Anionic catalysts such as sodium metal in N,N-dimethylformamide, sodium hydride in toluene, and phenylmagnesium bromide in toluene successfully initiate the polymerization. Monomers (I) and (II), did not polymerize by free radical catalysts, but monomer (II) could be polymerized by an ionic catalysts (Na in N,N-dimethylformamide). Monomer (III) was polymerized using phenylmagnesium bromide in toluene. This was apparently facilitated by the coordination of the magnesium atom to the heterocyclic nitrogen, which holds the catalyst complex in constant orientation. The N-oxides of the polymers of 2-(2-pyridyl)-1-propene (II) and 1-(2-pyridyl)-1-propene (III) were then prepared by oxidation by H₂O₂ in glacial acetic acid.