Co3O4 / NiO @ GQDs @ SO3H nanocatalyst has been used as an effective catalyst for the preparation of 2,4-diamino-6-arylpyrimidine-5-carbonitrile derivatives through a three-component reaction of malononitrile, aromatic aldehydes and guanidine hydrochloride under reflux conditions in ethanol. The catalyst has been characterized by FT-IR, XRD, SEM, EDS, BET, TGA, XPS and VSM. Atom economy, reusable catalyst, low catalyst loading, applicability to a wide range of substrates and high yields of products are some of the notable features of this protocol.The best results were gained in EtOH and we found that the reaction gave convincing results in the presence of Co3O4/NiO@GQDs@SO3H nanocomposite (4 mg) under reflux conditions. This green nanocatalyst could be used for other significant organic reactions and transformations. Further explorations of similar protocols are underway in our laboratory. This recoverable catalyst will provide a regular platform for heterogeneous catalysis, green chemistry, and environmentally benign protocols in the near future. Manuscript profile

Crosslinked sulfonated polyacrylamide (Cross- PAA- SO3H) attached to nano - Fe3O4 as an efficient heterogeneous solid acid catalyst has been used for the preparation of spiro[ pyrazoloquinoline - oxindoles] and spiro[ chromenopyrazolo - oxindoles] through a four-component reactions of phenylhydrazine or hydrazine hydrate, isatins, ketoesters and naphthylamine or 2 - naphthol under reflux condition in ethanol.Spirooxindoles have appeared as a series of significant heterocycles due to their presence in a wide spectrum of natural and synthetic organic compounds. These activities make spirooxindoles attractive goals in organic synthesis. The modifying crosslinked polyacrylamides make them attractive objects in chemistry and polymer science. Sulfonated polyacrylamides have unique characteristics such as high strength, hydrophilicity, and proton conductivity. The statistic of results from SEM images clearly demonstrate that the average size of Cross-PAA-SO3H@nano-Fe3O4 is about 7-25 nanometers. The remarkable advantages of this methodology are easy work-up, short reaction times, high to excellent product yields, operational simplicity, low catalyst loading and reusability of the catalyst. Manuscript profile

Functionalized SBA - 15 (Immobilization of Pd on the modified SBA - 15) has been utilized as an efficient catalyst for the preparation of chromenes by multi-component reactions of aromatic aldehydes, malononitrile and 4-hydroxycoumarin under reflux in ethanol. The catalyst has been characterized by X - ray diffraction spectroscopy ( XRD ), Field emission scanning electron microscopy ( FE - SEM ), Transmission electron microscopy (TEM), Energy-dispersive X - ray spectroscopy ( EDX ), X - Ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT - IR), N2 adsorption analysis, Temperature Programmed Desorption (TPD), and Differential thermal analysis (TGA - DTA). The structures of the products were deduced from their 1 H NMR, 13 C NMR, FT - IR, and elemental analyses. The advantages of this method include the reusability of the catalyst, low catalyst loading, excellent yields in short reaction times and easy separation of products, with no recrystallization required. Manuscript profile

Co3O4/NiO@GQDs@SO3H nanocatalyst has been used as an effective catalystfor the preparation of 2,4-diamino-6-arylpyrimidine-5-carbonitrile derivativesthrough a three-component reaction of malononitrile, aromatic aldehydes andguanidine hydrochloride under reflux conditions in ethanol. The catalyst has beencharacterized by FT-IR, XRD, SEM, EDS, BET, TGA, XPS and VSM. Atom economy,reusable catalyst, low catalyst loading, applicability to a wide range of substratesand high yields of products are some of the notable features of this protocol. Manuscript profile

Cross-linked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4 as an efficientheterogeneous solid acid catalyst has been used for the preparation of spiro[pyrazoloquinoline-oxindoles]and spiro[chromenopyrazolo-oxindoles] through a four-component reactions of phenylhydrazineor hydrazine hydrate, isatins, ketoesters and naphthylamine or 2-naphthol under reflux conditions inethanol. The remarkable advantages of this methodology are easy work-up, short reaction times, highto excellent product yields, operational simplicity, low catalyst loading and reusability of the catalyst. Manuscript profile

A rapid and efficient method for the synthesis of bis-thiazolidinones has been achieved by pseudo five-component reaction of aldehydes, ethylenediamine and thioglycolic acid in the presence of nano-NiZr4(PO4)6 as catalyst under microwave irradiation. Nano-NiZr4(PO4)6 has been characterized by powder X-ray diffraction, scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), thermogravimetric analysis (TGA) and FT-IR spectroscopy. In this research, microwave irradiation is used as a green and complementary technique for preparation of bis-thiazolidinones. Use of simple and readily available starting materials, excellent yields, short reaction times, reusability of the catalyst, low amount of catalyst and using of microwave as clean method are some advantages of this protocol. Manuscript profile

The preparation of trans-dihydrofurans has been achieved by a one-pot condensation reaction of 4-bromophenacyl bromide, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione using biosynthesized CuO nanoparticles under reflux conditions in ethanol. CuO nanoparticles (CuO NPs) were prepared using extractof leaves of Ajuga chamaecistus Subsp. Scoparia. The key advantages of this process are the diastereoselective synthesis, reusability of the catalyst, low catalyst loading, excellent yields, short reaction times, simple workup and environmentally benign. Fully optimized structures of trans and cis dihydrofurans were obtained by B3LYP/6-31G(d,p) method. The structures of the prepared trans-2,3-dihydrofurans were fully characterized by 1H and 13C NMR spectra, IR spectra, and elemental analysis. Manuscript profile

ZrP2O7 nanoparticles have been used as an efficient catalyst for the preparation of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones by a simple one-pot four-component reaction of phenyl hydrazines, ethyl acetoacetate ,β-naphthol and benzaldehydes under microwave irradiation in good to excellent yields. When the reaction was carried out using ZrOCl2.8H2O, ZrO2 and ZrP2O7 NPs as the catalyst, the product were obtained in moderate to good yield. The highest yield 92% was reached when the reaction was performed with 0.6 mol% of catalyst loading. Atom economy, green reaction, short reaction times, easy isolation of the targeted molecules, recovery and reusability of the catalyst are some of the important features of this protocol. Manuscript profile

ZrP2O7 nanoparticles (NPs) as an efficient catalyst have been used for the preparation of 1,6-diamino-2- oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives via one-pot coupling of hyrazine hydrate, ethyl cyanoacetate, malononitrile and aromatic aldehydes under reflux conditions in ethanol. Using this method we obtained low reaction times, easy isolation of the targeted molecules, excellent yields. Manuscript profile

Nanocrystalline ZnZr4(PO4)6 ceramics as an efficient catalyst have been used for the preparation of methyl 6-amino-5-cyano-4-aryl-2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylates by the four component reaction of dimethylacetylenedicarboxylate, hydrazinehydrate, malononitrile and aromatic aldehydes in water at room temperature. In this research Nano-ZnZr4(PO4)6 coordinate with the active groups(particular C=O, C≡N and active H) thus increasing the activity of the groups. Also this nanoscale heterogeneous catalysts present higher surface areas which are mainly responsible for their catalytic activity. These surface atoms behave as the centers where the chemical reactions could be catalytically activated. The key advantages of this process are high yields, shorter reaction times, reusability of catalyst, easy work-up, milder reaction conditions and environmentally benign. Manuscript profile

A proper, atom-economical, straightforward one-pot multicomponent synthetic route for the synthesis of benzopyranophenazines has been presented by the reaction of hydroxynaphthoquinone, o-phenylenediamine, benzaldehydes, and malononitrile with crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4as an efficient heterogeneous solid acid catalyst under ultrasonic irradiations in ethanol. Experimental simplicity, wide range of products, excellent yields in short reaction times and applying the sonochemical methodology as an efficient method and innocuous means of activation in synthetic chemistry for the preparation of medicinally privileged heterocyclic molecules are some of the important features of this method. The present catalytic procedure is extensible to a wide diversity of substrates for the synthesis of a variety-oriented library of benzopyranophenazines. Manuscript profile