Employing of Fe3O4/CuO/ZnO@MWCNT MNCs in the solvent-free synthesis of new cyanopyrroloazepine derivatives and investigation of biological activity.

In this research, we synthesized the Fe3O4/CuO/ZnO@MWCNT magnetic nanocomposites using water extract of Petasites hybridus rhizome, and the high performance of synthesized catalyst was confirmed by using in the solvent-free multicomponent reactions of isatoic anhydride, N-methylimidazole, alkyl bromides, activated acetylenic compounds and 2-aminoacetonitrile at ambient temperature for the production of new cyanopyrroloazepine derivatives in high yields. This catalyst could be used several times in these reactions and have main role in the yield of product. The synthesized cyanopyrroloazepines have NH groups in their structure and for this reason have good antioxidant activity. Also, employing Gram-positive and Gram-negative bacteria in the disk diffusion procedure confirmed some cyanopyrroloazepines antimicrobial effect. The results showed that synthesized cyanopyrroloazepine prevented the bacterial growth. This used process for preparation of new cyanopyrroloazepine has some improvements such as low reaction time, product with high yields, simple separation of catalyst and products.

An Efficient Synthesis of Pyrano[c]chromenediones and [1,3]Dioxolo[g] chromeneones Catalyzed by Nickel(II) Chromite Nanoparticles Through a Three-Component Domino Reaction.

BACKGROUND: Due to the importance of fused chromene motifs in bioactive compounds, the current research aimed to explore novel methods for the construction of heterocyclic scaffolds. Regarding the attractive features of developing novel methodological approaches in the presence of heterogeneous nanocatalysts, we will try to synthesize 4-aryl-3,4-dihydro-2H,5H-pyrano[3,2- c]chromene-2,5-diones and 8-aryl-7,8-dihydro-6H-[1,3]dioxolo[4,5-g]chromene-6-ones. OBJECTIVE: The aim of the present research was to prove the catalytic efficiency of the synthesized nickel(II) chromite nanoparticles (NiCr2O4 NPs) as bifunctional Lewis acid-Lewis base catalyst in the synthesis of pyrano[c]chromenediones and [1,3]dioxolo[g]chromeneones. METHODS: Pyrano[c]chromenediones and [1,3]dioxolo[g]chromeneones were conveniently prepared from a three-component condensation reaction between aromatic aldehydes, Meldrum's acid, and active methylene compounds including 4-hydroxycoumarin or 3,4-methylenedioxyphenol using NiCr2O4 NPs as an efficient, readily available, and recyclable catalyst, under ethanol-drop grinding at room temperature. The synthesized compounds were characterized by IR, 1H, and 13C NMR spectroscopy and also by elemental analyses. RESULTS: A number of 4-aryl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-diones and 8-aryl- 7,8-dihydro-6H-[1,3]dioxolo[4,5-g]chromene-6-ones were effectively synthesized as target compounds in high yields. CONCLUSION: This study provides a simple, inexpensive, and NiCr2O4 NPs catalyzed route to synthesis pyrano[c]chromenediones and [1,3]dioxolo[g]chromeneones in high yields. The reaction offers several benefits, including simple experimental procedures, higher yields, shorter reaction times, and the use of easily obtained and recyclable catalyst compared with previously reported methods and has a great scope for development.

Nickel(II) Chromite Nanoparticles: An Eco-Friendly and Reusable Catalyst for Synthesis of 2,4-Diamino-6-aryl-pyrimidine-5-yl Cyanides under Ultrasonic Radiation.

BACKGROUND: One of the principal factors in the field of research in green chemistry is to drive chemical reactions using ultrasonication as a versatile synthetic tool. Moreover, nanostructured metal salts occupy an important position as low cost, efficient, heterogeneous, and green catalysts in chemical reactions. Pyrimidine has also acquired significance because it is a core structure in a variety of natural and non-natural agents, many of which display versatile biological activities and medical applications. OBJECTIVE: The aim of this study was to explore the role of nickel(II) chromite nanoparticles (NiCr2O4 NPs) as a green and recyclable catalyst for the synthesis of 2,4-diamino-6-arylpyrimidine- 5-yl cyanides under ultrasonic radiation. METHODS: A direct cyclocondensation reaction of guanidine nitrate, aromatic aldehydes, and malononitrile was performed using NiCr2O4 NPs as an effective heterogeneous catalyst under ultrasonic radiation at room temperature conditions to prepare 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides in high yields. The described catalyst was prepared successfully according to a simple hydrothermal route and fully characterized by the X-Ray diffraction (XRD) technique, dispersive energy X-Ray (EDS) analysis, scanning electron microscopy (SEM), and dynamic light scattering (DLS). RESULTS: A number of 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides were effectively synthesized in high yields (94-98%) within short reaction times (15 min). All synthesized compounds were well characterized by IR, 1H and 13C NMR spectroscopy, and also by elemental analyses. CONCLUSION: In conclusion, a simple, efficient, and green synthesis of 2,4-diamino-6-arylpyrimidine- 5-yl cyanides was developed using NiCr2O4 NPs as a green nanocatalyst, and under ultrasound radiation as a green tool. The mild reaction conditions, avoiding the use of toxic solvents or reagents, high atom economy, high yields, and simple workup are the attractive features of this new protocol.

A PANI-Fe3O4@ZnO nanocomposite: a magnetically separable and applicable catalyst for the synthesis of chromeno-pyrido[d]pyrimidine derivatives.

We report herein green, practical, PANI-Fe3O4@ZnO-nanocomposite-catalyzed cyclocondensation reactions involving 4-aminocoumarin, 1,3-dimethylbarbituric acid, and aromatic aldehydes in an aqueous medium at room temperature to synthesize 9,11-dimethyl-7-aryl-6H-chromeno[3',4':5,6]pyrido[2,3-d]pyrimidine-6,8,10(9H,11H)triones. This research aims to provide an applicable and high-yield protocol that follows the principles of green chemistry, with the use of water as an environmentally benign medium and the PANI-Fe3O4@ZnO nanocomposite as a magnetically recoverable catalyst.