53531-57-0Relevant articles and documents
Pyridine Skeleton Synthesis Using Acetonitrile as C4N1 Units and Solvent
Bai, Chaolumen,Guo, Huifang,Liu, Xin,Liu, Dan,Sun, Zhaorigetu,Bao, Agula,Baiyin, Menghe,Muschin, Tegshi,Bao, Yong-Sheng
, p. 12664 - 12675 (2021/09/18)
The first [3 + 2 + 1] methodology for pyridine skeleton synthesis via cascade carbopalladation/cyclization of acetonitrile, arylboronic acids, and aldehydes was developed. This reaction proceeds via six step tandem reaction sequences involving the carbopalladation reaction of acetonitrile, a nucleophilic addition, a condensation, an intramolecular Michael addition, cyclization, and aromatization. Delightfully, both palladium acetate and supported palladium nanoparticles catalyzed this reaction with similar catalytic performance. The characterization results of the fresh and used supported palladium nanoparticle catalysts indicated that the reaction might be performed via a Pd(0)/Pd(II) catalytic cycle that began with Pd(0). Furthermore, the products showed good fluorescence characteristics. The green homogeneous/heterogenous catalytic methodologies pave a new way for constructing the pyridine skeleton.
Molecular Iodine-Mediated Chemoselective Synthesis of Multisubstituted Pyridines through Catabolism and Reconstruction Behavior of Natural Amino Acids
Xiang, Jia-Chen,Wang, Miao,Cheng, Yan,Wu, An-Xin
supporting information, p. 24 - 27 (2016/01/15)
A new process has been developed for the selective construction of 2,6-disubstituted, 2,4,6-trisubstituted, and 3,5-disubstituted pyridines based on the catabolism and reconstruction behaviors of amino acids. Molecular iodine was used as a tandem catalyst to trigger the decarboxylation-deamination of amino acids and to promote the subsequent formation of the pyridine products.
A modular synthesis of functionalized pyridines through lewis-acid-mediated and microwave-assisted cycloadditions between azapyrylium intermediates and alkynes
Linder, Igor,Gerhard, Markus,Schefzig, Luise,Andrae, Michal,Bentz, Christoph,Reissig, Hans-Ulrich,Zimmer, Reinhold
supporting information; experimental part, p. 6070 - 6077 (2011/12/02)
In this report we describe the synthesis of differentially functionalized pyridine derivatives 3 and the related 3-bromo-substituted pyridines 11. Dissociation of 6H-1,2-oxazine precursors (1a, 1b, 5, 6, or 12) in situ, mediated by boron trifluoride-diethyl ether, generates the azapyrylium intermediates A, which undergo hetero-Diels-Alder reactions with various mono- and disubstituted alkynes 2. In general, these pyridine syntheses proceeded with high efficiencies and were very flexible with respect to all positions in the pyridine cores. For the 3-phenyl-substituted pyridine derivatives 3a-3j and 11a-11f the best results were obtained by a new microwave-assisted protocol, which is clearly superior to the previously used conventional procedure at low temperature in dichloromethane. Furthermore, 3-(trifluoromethyl)- and 3-acryloyl-substituted 6H-1,2-oxazines reacted cleanly under microwave irradiation conditions to furnish the expected pyridine derivatives 3k and 3l in respectable yields. The 3-bromo-substituted pyridines 11 were further functionalized through palladium-catalyzed couplings such as Suzuki or Sonogashira reactions, which led smoothly to tri- or tetrasubstituted pyridine derivatives such as 19-21 and 23. Reductive debromination of 11e afforded the pyridine 17 in excellent yield, whereas oxidation of the pyridinyl thioether 3g with oxone led to the corresponding sulfoxide 24. Our method thus establishes a new and versatile approach to highly substituted pyridine derivatives. A simple method for the modular synthesis of substituted pyridines is disclosed. Microwave-assisted reactions between azapyrylium intermediates (generated in situ) and alkynes afforded the corresponding pyridine derivatives in good to excellent yields. The functional group tolerance in this process is very good and allows a variety of subsequent reactions.
