The synthesis and characterization of novel 1,3-benzyl-3,4,5,6-tetrahydropyrimidin-2-ylidene-based N-heterocyclic carbene palladium(II) complexes (1a−d) were described. The crystal structure of trans-dichlorobis[1,3-bis(4-methylbenzyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene]-palladium(II) was presented. Pd(II) complexes 1a−d were tested as catalysts in the direct C5 or C2 arylation of furans, thiophenes, and thiazoles, with various aryl bromides at 150°C for 1 h. These complexes exhibited moderate to high catalytic activities under the given conditions.
This review is focused on new developments reported during the last 3 years concerning the catalytic performances of in situ formed or preformed NHC-Pd(II) complexes (NHC: N -heterocyclic carbene) for cross-coupling reactions such as Heck-Mizoraki (often shortened to the Heck reaction), Kumada, Negishi, Suzuki-Miyaura (often shortened to the Suzuki reaction), Sonogashira and Hiyama couplings, and the Buchwald-Hartwig aminations, which are extremely powerful in the formation of C-C and C-heteroatom bonds. Due to the great number of publications and limited space here, we made a special attempt to compile the relevant data in tables, which we hope will serve as a guide for chemists interested in these reactions. The syntheses of the precatalysts and the generally accepted reaction mechanisms are also briefly described.
A series of vinyl functionalized 5,6-dimethylbenzimidazolium salts are synthesized.All compounds were fully characterized by elemental analyses, MS, 1 H-NMR, 13 C-NMR, and IR spectroscopy techniques. Enzyme inhibition is a very active area of research in drug design and development. In this study, the synthesized novel benzimidazolium salts were evaluated toward the human erythrocyte carbonic anhydrase I (hCA I), and II (hCA II) isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. They demonstrated highly potent inhibition ability against hCA I with K i
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