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Partitioning of neutron-poisoning lanthanides from minor actinides in used nuclear fuel using liquid-liquid separation techniques with moderately soft Lewis basic heterocyclic scaffolds is an area of intense research focus. Nitrogen heterocycles have demonstrated potential for the selective separation of Am3+ from Eu3+ in separations processes. Improved synthetic strategies are required to access more diversified complexant scaffolds for further study. The present work describes an efficient synthetic strategy for the preparation of functionalized [2,2′]-bipyridinyl scaffolds using Pd catalysis to prepare the requisite starting material and telescoped condensation to afford direct access to hemi-1,2,4-triazinyl-[2,2′]-bipyridines with aliphatic character and potentially greater solubility in less polar diluents. Synthetic method development, optimization, and substrate scope are reported herein. [ABSTRACT FROM AUTHOR]

The development of materials for efficient chemoselective extraction of minor actinides remains at the forefront of research efforts in the area of separation science. Lewis basic complexants derived from nitrogen-donor scaffolds are often employed in this area due to favorable with the transuranic element americium. In the present work an efficient procedure for the preparation of eight useful 3-pyridin-2-yl-1,2,4-triazines (2 novel) is demonstrated via telescoped condensation with the requisite 1,2-dicarbonyl in two-pots without additives, differentially extractive work-up procedures, or recrystallization. Additional efforts in this area have demonstrated the utility of polar aprotic solvents for the preparation of nine functionalized pyridinyl-2,6- bis-1,2,4-triazines (4 novel) directly from the requisite 2,6-pyridine dicarbonitrile in 49-99% yield over four total steps. The streamlined preparation of these important materials and detailed synthetic procedures is reported herein. [ABSTRACT FROM AUTHOR]

A Pd-catalyzed reaction of bis(bromophenyl) substituted 1,2,4-triazines (I) with primary amines (II) is developed to yield novel 4,4′-bisaminophenyl substituted monotriazinylpyridine derivatives (III) as potential ligands for chemoselective minor actinide extraction processes. [ABSTRACT FROM AUTHOR]