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DOI: 10.1055/s-0029-1218453
Three-Component Synthesis of Substituted Pyridines with Silica Nanoparticles
Contributor(s):Yasuhiro Uozumi, Yoshikazu YamamotoUniversity of South Dakota, Vermillion, USA
One-Step, Three-Component Synthesis of Highly Substituted Pyridines Using Silica Nanoparticle as Reusable Catalyst
Tetrahedron Lett. 2009, 50: 6959-6962
Publication History
Publication Date:
21 December 2009 (online)
Key words
pyridines - silica nanoparticles - multicomponent reaction
Significance
Silica nanoparticles (NPs) were prepared from tetraethyl orthosilicate (TEOS) via the water-in-oil microemulsion method with ammonium hydroxide in water and cyclohexane in the presence of Triton X-100 (eq. 1). Silica NPs (Æ = 50 nm) promoted the three-component reactions of aldehydes 1, malononitrile 2, and thiols 3 to give the corresponding 2-amino-3,5-dicarbonitrile-4-alkyl-6-sulfanylpyridines 4 in 60-85% yield (12 examples, eq. 2).
Comment
Silica NPs were characterized by TEM analysis. The catalytic activity of 50 nm of NPs was superior to that of 150-200 nm of NPs. The present silica NP catalyzed three-component synthesis afforded higher yields of 4 compared with hitherto reported methods (e.g., with Et3N: 20-40%, with piperidine: 60-81%, with ZnCl2: 45-67%).