Silica supported sodium hydrogen sulfate (NaHSO4–SiO2): A novel, green catalyst for synthesis of pyrazole and pyranyl pyridine derivatives under solvent-free condition via heterocyclic β-enaminones
摘要:
NaHSO4-SiO2 is used as an efficient, mild and reusable catalyst for the synthesis of novel heterocyclic pyrazole (5a-h) and pyranyl pyridine (7a-h) derivatives via heterocyclic beta-enaminones (3a-d) under thermal solvent-free conditions. The remarkable features of this green, new methodology are high conversions, cleaner reaction profile, simple experimental and work-up procedures. Structures of the newly synthesized compounds have been elucidated on the basis of elemental analysis and spectral data (IR, H-1 NMR, C-13 NMR and mass spectrometry). The catalyst is characterized for the first time by using scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and powder XRD. The catalyst can be reused several times without significant loss of its catalytic activity. (c) 2012 Elsevier B.V. All rights reserved.
Highly efficient solvent-free synthesis of novel pyranyl pyridine derivatives via β-enaminones using ZnO nanoparticles
作者:Zeba N. Siddiqui、Nayeem Ahmed、Farheen Farooq、Kulsum Khan
DOI:10.1016/j.tetlet.2013.04.072
日期:2013.7
Highly efficient ZnO nanoparticle catalyzed one-pot solvent-freesynthesis of novel pyridine derivatives by three-component reaction of β-enaminones, different active methylene compounds, and ammoniumacetate via Michael addition, cyclodehydration, and elimination sequence is reported. The catalyst was recyclable up to six catalytic cycles without a significant loss in the catalytic activity. This