63597-03-5Relevant academic research and scientific papers
Synthesis, crystal structure, and different local conformations of pyridine-imide oligomers
Zhu, Hengheng,He, Weiwei,Zhan, Chuanlang,Li, Xiao,Guan, Zisheng,Guo, Fengqi,Yao, Jiannian
, p. 8458 - 8464 (2011/11/13)
In this article, we report a new approach toward synthesis of pyridine-imide oligomers (PIOs). Using this approach, both dimer and trimer were one-pot synthesized from acylation of monomeric monoamide with monomeric dichloride. The yield of trimer was dependent on the alkoxyl terminals: it was 30% for methoyl group, whereas it was 95% for 3-chloro-1-propoxyl terminal. Acylation of dimeric monoamide with monomeric dichloride produced trimer, tetramer, and pentamer in a yield of 34%, 33%, and 28%, respectively. The synthesis was proposed to be mediated through an exchange between pyridine-2-carboxamide and pyridine-2-carbonyl chloride, both forming intramolecular or intermolecular hydrogen-bonds between pyridine-nitrogen and pyridine-2-amide hydrogen atoms. Crystal structure from three trimers with different terminal groups was reported. Analysis on the crystal structures revealed that these three trimers had different local conformations. The different local conformations were originated from the structural tunability of the imide unit in either the coplanarity or bond parameters.
Electrochemical reduction of some 2,6-disubstituted pyridine-based esters and thioic S-esters in acetonitrile
Webster, Richard D.,Bond, Alan M.,Schmidt, Thomas
, p. 1365 - 1374 (2007/10/03)
Voltammetric studies at glassy carbon, gold, mercury, platinum and silver electrodes on 2,6-disubstituted pyridine esters and thioic S-esters in acetonitrile have shown that they may be reduced at negartive potentials +> (Fc=ferrocene).The reduction process corresponds to a chemically reversible one-electron reduction step leading to the formation of a radical anion for many of the compounds at moderately high scan rates (>1-10 V s-1), but a lower scan rates the process appears chemically irreversible owing to the instability of the radical anion.Reduction is believed to occur in the carbonyl region of the molecules with the thioic S-esters being easier to reduce than the esters by ca. 300 mV and the reduction potential correlating with the strength of the C=O bond as measured by IR spectroscopy.Controlled potential electrolysis experiments performed on an ester and the analogous thioic S-ester showed that reduction of an ester on the long time domain experiments resulted in cleavage of the O-R bond while the thioic S-ester cleaved at the C(O)-S bond and underwent further reaction to form interesting and unusual products.The isolated products and mechanism of the reduction, as determined from voltammeric, kinetic, EPR spectroscopy and other spectroscopic data, are discussed in detail.The design and operation of a simple and efficient bulk electrolysis cell used in these experiments is also discussed.
