ABSTRACT
We report for the first time cyclic phosphine-free "head to tail" N,N,N pincer-like (pincer complexes mimicking) N-(pyrimidin-2-yl)-1,2-azole-3-carboxamide Pd(II) complexes with deprotonated amide groups as high-turnover catalysts (TON up to 106, TOF up to 1.2 × 107 h-1) for cross-coupling reactions on the background of up to quantitative yields under Green Chemistry conditions. The potency of the described catalyst family representatives was demonstrated in Suzuki-Miyaura, Mizoroki-Heck, and Sonogashira reactions on industrially practical examples. Corresponding ligands could be synthesized based on readily available reagents through simple chemical transformations. Within the complex structures, a highly unusual 1,3,5,7-tetraza-2,6-dipalladocane frame could be observed.
ABSTRACT
BACKGROUND: The nuclear-chemical method brought unique opportunity for synthesis of unknown and hardly available organic compounds. Presence of tritium labeling allows one-step preparation of radioactive markers for the investigation of chemical and biological processes. METHODS: The ion-molecular reactions of nucleogenic phenyl cations with 4-picoline have been carried out. The phenyl cations were generated by spontaneous tritium ß-decay within the tritium-labeled benzene. Both additions to the nitrogen and substitutions about the aromatic ring were able to be studied simultaneously. RESULTS: Unusual substitutions on both the α- and ß-positions of the ring system have been revealed. CONCLUSION: By unknown direct phenylation of nitrogen atom tritium-labeled N-phenylpicolinium derivatives, perspective biological markers have been synthesized.
