Synthesis Of Pyran Derivatives Research Articles

SO3H-Functionalized Epoxy-Immobilized Fe3O4 Core-Shell Magnetic Nanoparticles as an Efficient, Reusable, and Eco-Friendly Catalyst for the Sustainable and Green Synthesis of Pyran and Pyrrolidinone Derivatives.

A SO3H-functionalized epoxy-immobilized Fe3O4 core-shell magnetic nanocatalyst was prepared through a simple three-step procedure, and it was identified by various analyses such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential thermal gravity (DTG), Brunauer-Emmett-Teller (BET) analysis, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibration sample magnetometry (VSM), and powder X-ray diffraction (PXRD). BET analysis showed that the as-prepared nanocatalyst was synthesized with a mesoporous structure and high specific area (35.45 m2 g-1). The TEM image clearly showed that the particle size distribution was in the range of 47-65 nm. The designed magnetic nanocatalyst was used successfully in the synthesis of pyran derivatives via the reaction of dimedone, malononitrile, and various aromatic aldehydes and synthesis of pyrrolidinone derivatives via the reaction of various aromatic aldehydes, aniline, and diethyl acetylenedicarboxylate. The nanocatalyst was simply isolated from the reaction mixture utilizing an external magnet and reused several times according to the model reactions without significant loss in its efficiency.

Zn2SnO4-SnO2 Nano-Composite Promoted Ultrasonic-Assisted Synthesis of Pyran Derivatives

Zn2SnO4-SnO2 nano-composite is prepared via a sol-gel method in a watery media of sour orange and was characterized by XRD, FESEM, and TEM techniques. Next, Zn2SnO4-SnO2 nanocomposite was used as a catalyst for the synthesis of pyran derivatives via three-component reactions including malononitrile, active enols, and aldehydes leading to the formation of the pyran heterocycles under ultrasonic irradiation conditions in good to excellent yields.

Comparison of the efficiency of two imidazole-based dicationic ionic liquids as the catalysts in the synthesis of pyran derivatives and Knoevenagel condensations

In the present work, 3,3′-(butane-1,4-diyl)bis(1-methyl-1H-imidazol-3-ium) dichloride ([C4(MIm)2]·2Cl) and 3,3′-(butane-1,4-diyl)bis(1-methyl-1H-imidazol-3-ium) hydrogen sulfate ([C4(MIm)2]·2HSO4) were prepared via adequate, solvent-free methods and characterized using FT-IR, 1H NMR, 13C NMR, and potentiometric titration techniques. These reagents were investigated in the synthesis of 5-arylidene (thio)barbituric acids, 2-arylidene malononitriles, 4H-pyrans, and pyrano[2,3-d] pyrimidineones, and their catalytic activities were compared in the promotion of these reactions. Based on the obtained results, we found that [C4(MIm)2]·2Cl showed more catalytic efficiency where a basic or weak acidic media is needed. In contrast, [C4(MIm)2]·2HSO4 is a powerful catalyst in reactions needing acidic catalysts to enhance the reaction rate. Using these reagents, the products were formed under mild and eco-friendly conditions in excellent yields during short reaction times without needing column chromatography for work-up.

Polypyrrole/Fe3O4/CNT as a recyclable and highly efficient catalyst for one‐pot three‐component synthesis of pyran derivatives

Polypyrrole (PPY)/Fe3O4/CNT has been synthesized and characterized by FT‐IR, TEM and SEM techniques and its catalytic activity has been evaluated in the synthesis of several series of pyran derivatives. Tetrahydrobenzo[b]pyranes, 4H‐pyran‐3‐carboxylates, 4H,5H‐pyrano[3,2‐c]chromenes and dihydropyrano[2,3‐c]pyrazoles have been successfully prepared from one‐pot three‐component condensation of aldehyde, malononitrile and active methylene‐containing compounds (dimedone /ethyl acetoacetate/4‐hydroxycoumarin/3‐methyl‐2‐pyrazoline‐5‐one) using PPY/Fe3O4/CNT as a new and reusable heterogeneous catalyst. The present method offer several advantages such as; high yields of products, short reaction times, easy work‐up procedure and easy separation of the catalyst from the reaction mixture due to its magnetic character. Furthermore, chemoselective synthesis of bis‐benzo[b]pyran from terephthalaldehyde can be achieved by this method.

One-pot synthesis of pyran derivatives using silica-coated magnetic nanoparticles functionalized with piperidinium benzene-1,3-disulfonate as a new efficient reusable catalyst

Fe3O4 nanoparticles were coated with silica followed by surface modification using a silylating agent and piperidine to obtain piperidinium benzene-1,3-disulfonate salt (PBDS) silica-coated magnetic nanoparticles (SCMNPs). The obtained catalyst was then analyzed using various characterization techniques, including thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging, and X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and energy-dispersive X-ray (EDX) analyses. The heterogeneous catalytic activity was investigated in one-pot pseudo-three-component synthesis of pyran derivatives, revealing efficient action and giving the products in high yield under green and sustainable conditions. A novel efficient green reusable catalyst was obtained from silica-coated magnetic nanoparticles functionalized with piperidinium benzene-1,3-disulfonate for synthesis of 9-aryl-9H-2,4,5,7-tetramethyl-diuracilopyrans as well as 9-aryl-3,4,6,7-tetrahydro-2H-pyran-1,8(5H,9H)-diones.

Ferromagnetic α-Fe2O3 NPs: a potential catalyst in Sonogashira–Hagihara cross coupling and hetero-Diels–Alder reactions

Applications of in situ generated ferromagnetic α-Fe2O3 NPs as an efficient and recyclable catalyst for carbon–carbon bond formation via Sonogashira–Hagihara coupling reactions and the synthesis of pyran derivatives by hetero-Diels–Alder reactions have been demonstrated.

Synthesis of pyran derivatives under ultrasound irradiation using Ni nanoparticles as reusable catalysts in aqueous medium

Abstract Ni nanoparticles (NPs)-catalysed synthesis of pyran derivatives was achieved by one-pot three-component reactions of aryl aldehydes/ketone, malononitrile and C–H activated compounds in aqueous medium under ultrasound irradiation. The present approach offer several advantages, such as shorter reaction time, higher yields, and environmental friendliness.

ChemInform Abstract: Reactions of 3-Oxo-2,3-dihydrobenzofuran with Alkyl 2-Cyano-3- alkoxypropenoate and Alkyl 2-Alkoxycarbonyl-3-alkoxypropenoate. Synthesis of Pyran Derivatives.

3-Oxo-2,3-dihydrobenzofuran reacted with ethyl 2-cyano-3-ethoxypropenoate, methyl 2-cyano-3-methoxy-propenoate affording compounds 3 (2-(2-cyano-2-alkoxycarbonylvinyl)-3-hydroxybenzofuran) obtained as a mixture of Z + E isomers. Methyl 2-methoxycarbonyl-3-methoxypropenoate gave compound 4. Malonic compounds added on 2-dimethylaminomethylene-3-oxo-2,3-dihydrobenzofuran 6 for giving compound 3 or 2-oxo-3-methoxycarbonyl-2H-pyrano[3,2-b]benzofuran 8. Compound 8 was also obtained by heating compound 4 in xylene.

A Convenient and Clean Procedure for the Synthesis of Pyran Derivatives in Aqueous Media Catalysed by Tebac

A clean and simple synthesis of 6-amino-5-cyano-4-aryl-2-methyl-4 H-pyran-3-carboxylate derivatives was accomplished in high yields via the reaction of arylmethylidenemalononitriles with acetoacetate in aqueous media catalysed by triethylbenzylammonium chloride (TEBAC). The structures were established by spectroscopic data and further confirmed by X-ray analysis.

ChemInform Abstract: Synthesis of Pyran Derivatives with Mesomorphic Properties.

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Reactions of 3‐oxo‐2,3‐dihydrobenzofuran with alkyl 2‐cyano‐3‐alkoxypropenoate and alkyl 2‐alkoxycarbonyl‐3‐alkoxypropenoate. Synthesis of pyran derivatives

Abstract3‐Oxo‐2,3‐dihydrobenzofuran reacted with ethyl 2‐cyano‐3‐ethoxypropenoate, methyl 2‐cyano‐3‐methoxy‐propenoate affording compounds 3 (2‐(2‐cyano‐2‐alkoxycarbonylvinyl)‐3‐hydroxybenzofuran) obtained as a mixture of Z + E isomers. Methyl 2‐methoxycarbonyl‐3‐methoxypropenoate gave compound 4. Malonic compounds added on 2‐dimethylaminomethylene‐3‐oxo‐2,3‐dihydrobenzofuran 6 for giving compound 3 or 2‐oxo‐3‐methoxycarbonyl‐2H‐pyrano[3,2‐b]benzofuran 8. Compound 8 was also obtained by heating compound 4 in xylene.

Synthesis of pyran derivatives with mesomorphic properties

N-(4-Arylidene)-4′-(3,6-dihydro-4-methyl-2H-pyran-3-yloxy)anilines and N-(4-arylidene)-4′-[(5,6-dihydro-2H-pyran-4-yl)methoxy]anilines that have the properties of smectic and nematic liquid crystals were synthesized. The effect of the pyran ring and the length of the aliphatic radical on the type and thermal stability of the meso phase was elucidated.

ChemInform Abstract: Reactions with Phosphacumulenes: Synthesis of Pyran Derivatives from the Reaction of N‐Phenyliminoketenylidene Triphenylphosphorane with α,β‐Unsaturated Carbonyl Compounds.

AbstractThe iminoketenylidene phosphorane (I) is coupled with the benzylidene derivatives (IIa) ‐ (IIc) to produce the pyran‐substituted phosphoranes (III).

Activated Nitriles in Heterocyclic Synthesis: A New Approach for the Synthesis of Pyran Derivatives

Activated Nitriles in Heterocyclic Synthesis: A New Approach for the Synthesis of Pyran Derivatives