Zinc—Proline Complex: An Efficient, Reusable Catalyst for Direct Nitroaldol Reaction in Aqueous Media.

AbstractThe design, preparation and characterization of a novel composite based on functionalization of halloysite nanoclay with Schiff base followed by immobilization of copper iodide as nanoparticles is revealed. This novel nano composite was fully characterized by utilization of FTIR, SEM/EDX, TGA, XRD and BET techniques. This Cu(I) NPs immobilized onto halloysite was successfully examined as a heterogeneous, thus easily recoverable and reusable catalyst in one of classist organic name reaction so-called “Click Reaction”. That comprised a three component reaction of phenylacetylene, α-haloketone or alkyl halide and sodium azide in aqueous media to furnish 1,2,3‐triazoles in short reaction time and high yields. Remarkably, the examination of the reusability of the catalyst confirmed that the catalyst could be reused at least six reaction runs without appreciable loss of its catalytic activity.

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Aqueous Media Preparation of Pyrido[d]pyrimidines Over Calcined TiO2- SiO2 Nanocomposite as an Efficient Catalyst at Ambient Temperature

Letters in Organic Chemistry ◽

10.2174/1570178616666181210102146 ◽

2019 ◽

Vol 16 (11) ◽

pp. 915-921

Author(s):

Nafiseh Yaltaghian-Khiabani ◽

Shahrzad Abdolmohammadi ◽

Sepehr Sadegh-Samiei

Keyword(s):

Ambient Temperature ◽

Titanium Dioxide Nanoparticles ◽

Wide Spectrum ◽

High Surface ◽

Aqueous Media ◽

Reusable Catalyst ◽

Efficient Catalyst ◽

X Ray ◽

Three Component Reaction ◽

High Yields

Pyridopyrimidines represent a highly important class of compounds which exhibit a wide spectrum of biological properties. Nanoscale metal oxide catalysts have been extensively studied for their application in organic reactions owing to their special features such as high surface area and pore sizes as supports. Titanium dioxide nanoparticles (TiO2 NPs) are an attractive candidate for readily available cheap nanocatalysts, due to their unique properties such as being non-toxic, moisture stable and reusable catalyst. 7-amino-2,4-dioxo-5-aryl-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-6-carbonitriles were synthesized through the reaction of 4(6)-aminouracil, aromatic aldehydes, and malononitrile using calcined TiO2-SiO2 nanocomposite as a reusable catalyst in water at ambient temperature. All the synthesized compounds were well characterized by their elemental analyses, IR, 1H and 13C NMR spectroscopy. The synthesized catalyst was fully characterized by the powder X-ray diffraction (XRD), the scanning electron microcopy (SEM), the transmission electron microscopy (TEM), and the x-ray fluorescence (XRF) techniques. The reaction proceeded through calcined TiO2-SiO2 nanocomposite catalyzed three-component reaction affording twelve target compounds in high yields. This method introduced a novel protocol to provide 7-amino-2,4-dioxo-5-aryl-1,2,3,4-tetrahydropyrido[2,3- d]pyrimidine-6-carbonitrile derivatives and offer several advantages like very simple operation, using inexpensive, recyclable and non-toxic catalyst, mild reaction conditions, high yields of products (92- 98%), short reaction times (2.5-4 h), and green aspects by avoiding toxic catalysts and hazardous solvents.

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Grinding Synthesis of Pyrazolyl-Bis Coumarinyl Methanes Using Potassium 2-Oxoimidazolidine-1,3-diide

Current Organic Synthesis ◽

10.2174/1570179416666190101142542 ◽

2019 ◽

Vol 16 (2) ◽

pp. 303-308 ◽

Cited By ~ 2

Author(s):

Kazem Hematinezhad ◽

Mohammad Nikpassand ◽

Leila Zare Fekri

Keyword(s):

Reaction Time ◽

Room Temperature ◽

Aqueous Media ◽

13C Nmr Spectroscopy ◽

Reusable Catalyst ◽

Reduced Pressure ◽

Elemental Analyses ◽

Nucleophilic Addition Reaction ◽

High Yields ◽

Work Up

Aim and Objective: Potassium 2-oxoimidazolidine-1,3-diide (POImD) as a novel and reusable catalyst was used for the synthesis of pyrazolyl-bis coumarinyl methanes by a nucleophilic addition reaction of synthetized pyrazolecarbaldehyde and two equivalents of 4-hydroxycoumarin under grinding. The catalyst can be reused and recovered several times without loss of activity. This method provides several advantages such as eco-friendliness, simple work-up and shorter reaction time as well as excellent yields. All of the synthesized compounds were characterized by IR, 1H and 13C NMR spectroscopy and elemental analyses. Material and Method: Synthetized pyrazole carbaldehyde 1a (1 mmol), 4-hydroxycoumarin 2 (2 mmol), 1 mmol of POImD and 10mL of H2O were ground in a mortar by a pestle for 30-90 minutes. After the completion of the reaction, as monitored by TLC on silica gel using ethyl acetate/n-hexane (1:2), the mixture was allowed to cool to room temperature. After completion of the reaction, we extracted the product with CH2Cl2/H2O. This was followed by separation of phases, evaporation of the organic phase and recrystallization of the residue with 50 mL of ethanol/H2O (1:1). The pure product was then obtained in 87 to 96% yield. The aqueous phase was concentrated under reduced pressure to recover the catalyst for subsequent use. Results: To continue our ongoing studies to synthesize heterocyclic and pharmaceutical compounds by mild, facile and efficient protocols, herein we wish to report our experimental results on the synthesis of pyrazolylbis coumarinyl methanes, using various synthetized pyrazole carbaldehydes and 4-hydroxycoumarin in the presence of POImD in aqueous media at room temperature. Conclusion: Finally, we developed an efficient, fast and convenient procedure for the three-component synthesis of pyrazolyl-bis coumarinyl methanes through the reaction of pyrazole carbaldehydes and 4- hydroxycoumarin, using POImD as a novel and reusable catalyst. The remarkable advantage offered by this method is that the catalyst is non-toxic, inexpensive, easy to handle and reusable. A short reaction time, simple work-up procedure, high yields of product with better purity and the green aspect by avoiding a hazardous solvent and a toxic catalyst are the other advantages. To the best of our knowledge, this is the first report on the synthesis of pyrazolyl-bis coumarinylmethane derivatives using potassium 2-oxoimidazolidine-1,3-diide (POImD).

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