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An efficient strategy has been developed for the N-arylation of azoles and aliphatic amines with aryl halide using a Cu2O/nano-CuFe2O4 magnetic composite as the catalyst and KOH as the base. The me...

A cost-effective, highly useful and eco-friendly procedure for the one-pot synthesis of highly substituted pyrazole derivatives has been developed via the reaction of various aldehydes, malononitrile and phenylhydrazine or 4-phenylthiosemicarbazide in PEG-400 and water at room temperature under ultrasound irradiation. Utilization of green solvents without a catalyst makes this methodology very interesting from economic and environmental perspectives. This method provides several advantages such as operational simplicity, use of accessible and economical starting materials and reduced environmental consequences.

The title synthesis is advantageous with regards to high yields, mild reaction conditions and good functional group tolerance.

The title catalyst can be recovered using an external magnet and reused several times without significant loss of activity.

A new approach utilizing graphite oxide as an oxidizing agent is applied for the oxidative aromatization of 1,4-dihydropyridines. Graphite oxide efficiently aromatized Hantzsch 1,4-dihydropyridines into their corresponding pyridine derivatives in excellent yields. The reaction was carried out in toluene at 100 °C.

Silica sulfuric acid as a reusable and efficient catalyst has been used for the preparation of 12-aryl-8,9,10,12-tetrhydro benzo[a]xanthene-11-one derivatives from the one-pot multicomponent reaction of aromatic aldehydes, β-naphthol, and a cyclic diketone under solvent-free conditions. Good yields, simple procedure, easy workup, short reaction times, and mild conditions are the advantages of this methodology.

The efficient use of cellulose sulfuric acid as a heterogeneous catalyst promotes three-component, one-pot Mannich reaction of various ketones, aromatic aldehydes, and aromatic amines in ethanol to make the corresponding β-amino ketones with high stereoselectivity in favor of the anti-isomer. This protocol has several advantages such as good yield, mild reaction conditions, no environmental hazards, and simple workup procedure.

A convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3-indanedione at room temperature in PEG-400 is described. The use of PEG-400 as the reaction medium and avoiding the use of any catalyst makes the process environmentally benign. Seven new compounds are reported.

Cellulose-supported Ni(NO3)2 is used as novel reagent for the regioselective formation of o-nitro phenols.

Certain phenols and naphthols were nitrated regioselectively with Zn(NO 3 ) 2 ·6H 2 O/TCT in acetonitrile as solvent at room temperature and short reaction time in good yields. The reaction condition was mild. TCT is a cheap and commercially available reagent. It performed as an acid catalyst in this transformation.

Ammonium acetate and basic alumina catalyzed efficiently the Knoevenagel condensation of aldehydes and ketones with active methylene compounds under solvent-free condition where olefinic products were obtained in high yields.

A series of aromatic aldehydes are turned in to 3,3,6,6-tetramethyl-9-aryl-1,8-dioxooctahydroxanthene derivatives using trichloroisocyanuric acid (TCCA) as the catalyst.

Silica supported perchloric acid (HClO 4 /SiO 2 ) is found to be a heterogeneous recyclable catalyst for rapid and efficient synthesis of 1,8-dioxo-octahydroxanthenes with good to excellent yields in solvent free conditions. The catalyst is easily prepared, stable, reusable and efficiently used under reaction condition.

The HClO 4 –SiO 2 catalyzed three-component, one-pot Mannich reaction of ketones, aromatic aldehydes and aromatic amines is carried out in ethanol to afford the corresponding β-amino ketones in good yields and high stereoselectivities in favor of the anti -isomer. Three new compounds are reported.

Certain phenols and naphthols were nitrated regioselectively with zeofen in dichloromethane as solvent at room temperature and in a short reaction time to give good yields.