Preparation of Piperidinylpyridines via Selective Reduction of Bipyridines with Nickel-Aluminum Alloy

Article abstract of DOI:10.1021/jo00049a046

Bipyridines were reduced to piperidinylpyridines in modest yield using nickel-aluminum alloy in potassium hydroxide solution.The reduction was selective, and 3-substituted rings were reduced in preference to 4-substitution.Thus 2,3-bipyridine gave only 2-(3'-piperidinyl)pyridine, 2,4-bipyridine gave only 2-(4'-piperidinyl)pyridine, and 3,4-bipyridine gave only 4-(3'-piperidinyl)pyridine.The symmetrical 2,2'- and 4,4'-bipyridines also gave the corresponding piperidinylpyridines, but the reduction of 3,3'-bipyridine was too sluggish to be practical.The products were identified using 13C NMR spectroscopy, and the 13C NMR spectra of the starting bipyridines were also recorded.