A new electrochemical procedure for the electrocatalytic carboxylation of 2-amino-5-bromopyridine with CO
2 in ionic liquid, 1-butyl-3-methyllimidazolium tetrafluoborate (BMIMBF
4), to ...6-aminonicotinic acid was investigated for the first time. The experiments were carried out in three electrodes undivided cell under mild conditions, and the use of volatile and toxic solvents and catalysts, as well as any other additional supporting electrolytes, was avoided. The electrochemical reduction behavior of 2-amino-5-bromopyridine in BMIMBF
4 had been studied by cyclic voltammetry with a reduction peak at −1.6
V (vs. Ag). 6-Aminonicotinic acid was obtained in 75% yield and 100% selectivity, under the optimized condition. Moreover, the ionic liquid was successfully recycled.
Silver(I) complexes Ag(NO3)(3-Xpy)2, X=Cl (1), Br (2), I (3), were prepared and characterized by IR and NMR spectroscopy, by mass spectrometry and by powder and single-crystal X-ray analysis. Single ...point DFT calculations, followed by NPA and QTAIM analyses, were performed. In vitro tests of all complexes shown antibacterial activity. Display omitted
Three 1:2 complexes of Ag(I) nitrate with 3-halopyridine of the general formula Ag(NO3)(3-Xpy)2, X=Cl (1), Br (2), I (3), were prepared and characterized by elemental analysis, IR spectroscopy, mass spectrometry, multinuclear NMR spectroscopy in solution (1H, 13C, 15N, 109Ag) and in the solid state (13C, 15N), by powder and by single-crystal (1 and 3) X-ray analysis. Data showed that in complexes 1 and 3 the Ag atoms are coordinated by two halopyridine ligands through the N atoms and by various number of nitrate groups resulting in three-, four- and five-coordinated Ag atoms. Single point DFT calculations, followed by NPA and QTAIM analyses, were performed to understand the nature of bonding in the crystal structures. Three types of interactions were detected: coordinate Ag–N bonding, weaker Ag–O ionic bonding and in 3 weak Ag–Ag closed-shell bonding with a small covalent contribution. In vitro tests of all complexes gave better antibacterial activity when tested against Gram-negative than Gram-positive strains.
Two families of copper complexes, (3-X′-2-MepyH)2CuX4 and (3-X′-2-Mepy)2CuX2 have been synthesized and studied by single crystal X-ray diffraction and variable temperature magnetic susceptibility ...3-X′-2-Mepy=3-halo-2-methylpyridine, X′=Cl, Br; X=Cl, Br. Display omitted
► Two families of Cu(II) halide compounds of (3-halo-2-methylpyridine and 3-X′-2-Mepy) are described. ► They have been characterized by IR, X-ray diffraction and magnetic susceptibility. ► Most of the compounds show weak antiferromagnetic interactions. ► (3-Cl-2-Mepy)2CuCl2 crystallizes as a dimer and exhibits moderate antiferromagnetic exchange. ► (3-Cl-2-MepyH)2CuBr2 behaves as a well isolated 2D-square Heisenberg.
Two families of compounds have been prepared from the reaction of 3-X′-2-methylpyridine with CuX2 (X, X′=Cl, Br) in the presence or absence of HX. Four salts, (3-X′-2-methylpyridinium)2CuX4 were prepared, three of which crystallize in the orthorhombic space group Pbcn while the fourth (X=Br and X′=Cl) crystallizes in the monoclinic space group C2/c. All four neutral compounds of formula (3-X′-2-methylpyridine)2CuX2 crystallize in the space group P1¯. Of these, three form weakly bridged chains via long Cu⋯X contacts, while the fourth (X=X′=Cl) forms centrosymmetric dimers. Most of the complexes exhibit only very weak antiferromagnetic interactions and can be modeled as weak uniform chains. Compound 4, (3-Cl-2-methylpyridinium)2CuBr4, shows behavior that models an isolated 2D-Heisenberg antiferromagnetic layer with J=−5.09(2)K, while compound 7, (3-Cl-2-methylpyridine)2CuCl2, crystallizes as a bichloride bridged centrosymmetric dimer with J=−29.31(6)K.
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A solvent free direct amination of halo-(pyridine or pyrimidine) has been developed in good to high yields under computer-controlled microwave irradiation without transition metal catalyst. ...This reaction is a solvent and metal free, useful method for coupling of halo-(pyridine or pyrimidine) with pyrrolidine and piperidine derivatives by nucleophilic aromatic substitution (S
NAr).
Large quantities of an enantiomerically pure novel dual PPARα/γ agonist were required. Three routes were successfully developed to achieve this goal, with the chosen route utilized to deliver 40
g of ...material.
A series of pyridine ether PPAR agonists were synthesized through intermolecular palladium-catalyzed coupling of 2-halopyridines and alcohols. This method proved to be versatile, efficient, and ...amenable to parallel synthesis.
Palladium acetate-catalysed Suzuki reaction of halopyridines and arylboronic acids has been investigated in room-temperature ionic liquids in the absence of the phosphine ligand. A significant effect ...of water on the efficiency of the Suzuki reaction in ionic liquids was observed. The mixture of ionic liquid and water significantly enhanced the rate of the coupling reaction. The separation of the product was easily performed by extraction with diethyl ether and the Pd(OAc)2-bmimPF6 (1-butyl-3-methylimidazolium hexafluorophosphate) can be reused six times with only a small loss of reactivity.
A convenient and clean synthesis of halopyridine-2-amines has been provided by amination of halopyridines on KF-alumina under microwave irradiation with good yields.
Direct photolyses of 2-halopyridine in various solvents afforded the corresponding ionic products, as well as the radical product pyridine, while 3- and 4-halopyridines produced pyridine exclusively. ...The formation of the ionic products may occur via the 2-pyridyl cation generated through the initial photo-included homolytic cleavage of the C-X bond followed by electron transfer within the resulting radical pair. The participation of the unshared pair of electrons adjacent to the radical carbon is suggested to be important for releasing the unpaired electron.
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