Efficient atom-economical solvent-free one-pot multicomponent synthesis of 2-amino-4H-benzo[b]pyrans catalyzed by solid base SiO2-OK as a reusable catalyst
One-pot synthesis of highly substituted pyridines has been demonstrated via multicomponent reaction of aldehydes, malononitrile and thiophenol using Mg-Al hydrotalcite as a solid base and reusable catalyst. The catalytic activity is intimately connected to the basicity of the catalyst. The best activities were observed with the Mg/Al: 5 catalyst. The catalyst could be reused for further run without a significant loss in activity. The protocol was also applicable for various aromatic aldehydes which affords desired product in good to excellent yield.
β-Cyclodextrin-butane sulfonic acid efficiently catalyzed the synthesis of 1-amidoalkyl-2-naphthols by a one-pot three component condensation of aromatic aldehydes, β-naphthol and amides under solvent-free conditions.
Herein, a facile one-pot multicomponent protocol for the synthesis of biologically important pyrano[2,3-c]pyrazole and benzylpyrazolyl coumarin derivatives has been demonstrated using ZrO2 nanoparticles as reusable catalyst at room temperature.
An environmentally benign, one-pot, A3-coupling reaction of various aldehydes, amines and terminal alkynes for the synthesis of propargylamine was catalysed by Amberlyst A-21 supported CuI, under heterogeneous and solvent-free conditions.
A combinatorial library of benzylpyrazolyl coumarin derivatives have been synthesized by a green one-pot four-component reaction between aryl hydrazine/hydrazine hydrate (1), ethyl acetoacetate (2), aromatic aldehydes (3) and 4-hydroxycoumarin (4) catalyzed by niobium pentachloride with silver salt under solvent-free conditions has been developed. Experimental simplicity, simple work-up procedure and solvent-free reaction condition at room temperature are important features of the present protocol.
One-pot multicomponent synthesis of highly substituted pyridines using hydrotalcite as a solid base and reusable catalyst