5-substituted 1H-tetrazoles Research Articles

Synthesis of 5-Substituted 1H-Tetrazoles Catalyzed by M-SAPO-34 (M = Co, Cu, Mn, Fe, and V) Nanostructures

The synthesis of 5-substituted 1H-tetrazoles by use of a series of M-SAPO-34 (M = Co, Cu, Mn, Fe, and V) nanocatalysts are presented. Following the optimized conditions, Co-SAPO-34 nanocatalyst has been found to effectively catalyze the 5-substituted 1H-tetrazoles in DMF under heating conditions. The M-SAPO-34 as an easily accessible heterogeneous catalyst is highly efficient and recyclable. Some of the tetrazole derivatives were synthesized from nitriles derivatives and sodium azide. All the compounds were characterized and formed in good to excellent yields.

Synthesis and Characterization of Magnetic Functionalized Ni and Cu Nano Catalysts and Their Application in Oxidation, Oxidative Coupling and Various Multi-Component Reactions

Two magnetic nano catalysts of nickel and copper, Fe3O4@SiO2@DOP-BenPyr-M(II), (M=Ni and Cu) have been synthesized. These catalysts were applied as recoverable, efficient and new heterogeneous catalysts for the high yielding and room temperature one-pot procedure of selective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides. In addition, the catalytic activity of Fe3O4@SiO2@DOP-BenPyr-Ni(II) was investigated as heterogeneous nanocatalyst for synthesis of 2,3-dihydroquinazolin-4(1H)-ones, 5-substituted 1H-tetrazoles and polyhydroquinolines. The synthesized catalysts were characterized by FT-IR, TGA, XRD, VSM, EDX, ICP and SEM techniques. These catalysts were recovered by an external magnet and reused several times without significant loss of catalytic efficiency.

Retraction: A rapid and novel method for the synthesis of 5-substituted 1H-tetrazole catalyzed by exceptional reusable monodisperse Pt NPs@AC under the microwave irradiation.

Retraction for ‘A rapid and novel method for the synthesis of 5-substituted 1H-tetrazole catalyzed by exceptional reusable monodisperse Pt NPs@AC under the microwave irradiation’ by Esma Erken et al., RSC Adv., 2015, 5, 68558–68564, DOI: 10.1039/C5RA11426H.

Retraction: Monodisperse Pt NPs@rGO as highly efficient and reusable heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazole derivatives

Retraction of ‘Monodisperse Pt NPs@rGO as highly efficient and reusable heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazole derivatives’ by İbrahim Esirden et al., Catal. Sci. Technol., 2015, 5, 4452–4457, DOI: 10.1039/C5CY00864F.

Highly Active and Reusable Cu/C Catalyst for Synthesis of 5-Substituted 1H-Tetrazoles Starting from Aromatic Aldehydes

A new, efficient and convenient method for the synthesis of 5-substituted 1H-tetrazole derivatives with a wide range of substituents in good to excellent yields has been developed. The synthesis was performed by the one-pot three-component [3+2]cycloaddition reaction between aldehyde, hydroxylamine and sodium azide in the presence of Cu/C. The reaction probably proceeds by the in situ formation of nitriles followed by successive [3+2]cycloaddition with sodium azide. A variety of aldehydes were used to obtain the corresponding tetrazoles. The catalyst was recovered by simple filtration and reused at least five times without significant loss of catalytic activity. The use of this method offers additional advantages for the synthesis of 5-substituted 1H-tetrazole derivatives, including the easy availability of starting materials, mild conditions, experimental simplicity and good yields.

Catalytic conversion of 2,4,5-trisubstituted imidazole and 5-substituted 1H-tetrazole derivatives using a new series of half-sandwich (η6-p-cymene)Ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazone ligands

A new series of half-sandwich (η6-p-cymene) ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazide derivatives [Ru(η6-p-cymene)(Cl)(L)] [L = N'-(naphthalen-1-ylmethylene)thiophene-2-carbohydrazide (L1), N'-(anthracen-9-ylmethylene)thiophene-2-carbohydrazide (L2) and N'-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (L3)] were synthesized. The ligand precursors and their Ru(II) complexes (1–3) were structurally characterized by spectral (IR, UV–Vis, NMR and mass spectrometry) and elemental analysis. The molecular structures of the ruthenium(II) complexes 1–3 were determined by single-crystal X-ray diffraction. All complexes were used as catalysts for the one-pot three-component syntheses of 2,4,5-trisubstitued imidazole and 5-substituted 1H-tetrazole derivatives. The catalytic studies optimized parameters as solvent, temperature and catalyst. The catalysts revealed very active for a broad range of aromatic aldehydes presenting either electron attractor or electron donor substituents and, although less active, moderate to high activities were observed for alkyl aldehydes.

Methionine-Coated Fe3O4 Nanoparticles: An Efficient and Reusable Nanomagnetic Catalyst for the Synthesis of 5-Substituted 1H-Tetrazoles

Methionine-coated Fe3O4 nanoparticles, a magnetically reusable and environmentally friendly heterogeneous catalyst, was synthesized. The new catalyst was characterized by FT-IR spectra, XRD, SEM, and EDX analysis and was used to catalyze the cycloaddition of nitriles and sodium azide in DMSO at 120°C to give the corresponding 5-substituted 1H-tetrazoles. Methionine-coated Fe3O4 nanoparticles proved to be highly efficient for this organic reaction. The catalyst can be easily separated and reused several times without loss of activity. The proposed procedure also offers several benefits such as quick reaction, high yields, clean process, low-cost heterogeneous catalyst, low loading of catalyst, and simple operation.

L-cysteine complex of palladium onto mesoporous channels of MCM-41 as reusable, homoselective and organic–inorganic hybrid nanocatalyst for the synthesis of tetrazoles

In this study, ordered structure with a hexagonal arrangement MCM-41 was synthesized and functionalized with L-cysteine group and further palladium particles has been supported on its surface (L-cysteine-Pd@MCM-41). The prepared catalyst is well characterized by various techniques such as low-angle X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption–desorption measurement isotherms, energy-dispersive X-ray spectroscopy (EDS), X-ray Mapping (WDX), scanning electron microscopy (SEM) and inductively coupled plasma (ICP) techniques. The collected data from all techniques provided evidence that palladium complex was immobilized onto MCM-41 pores. The obtained nanocatalyst demonstrated excellent activity as a new heterogeneous catalyst for the homoselective synthesis of 5-substituted 1H-tetrazole derivatives. This method has the advantages of simple methodology, eco-friendly and simplicity in the separation of catalyst, shorter reaction times, and high yields of the product. Finally, easy catalyst recovery was achieved and the catalyst could be recycled for six times without a significant decrease in activity and selectivity.

Green alternatives for the synthesis of tetrazolic acids

Tetrazolic acids (5-substituted 1H-tetrazoles) are of great interest due to their bioisosterism with carboxylic acids, which accounts for plethora of their pharmacological activities and medicinal applications. Many reports deal with the synthesis of tetrazolic acids using different reactions and synthetic methods. This review intends to summarize most of the green approaches available for obtaining these heterocycles. The starting point in the discussion is the application of multicomponent reactions for the construction of structurally diverse products. However, the most commonly used reaction to afford tetrazolic acids is 1,3-dipolar cycloaddition of azide ion to nitriles. Hence, transition from homogeneous catalysis employed in the early examples of this method to heterogeneous catalysis applying recoverable reagents is highlighted. Similarly, the quest for eco-friendly reaction medium is thoroughly described stressing the use of novel systems like ionic liquids and deep eutectic solvents, reactions in aqueous medium, and solvent-free conditions. Further discussion emphasizes the advantages offered by solid-phase synthesis and nonconventional microwave-assisted reactions. Finally, several examples of successful combinations of different green tactics in a same experimental procedure are presented. Thereby, this article aims to provide the main trends for achieving synthesis of tetrazolic acids using environmentally benign procedures reported in the literature while giving perspectives of possible future advances in this topic.

Synthesis of 5-Substituted 1H-Tetrazoles from Nitriles by Continuous Flow: Application to the Synthesis of Valsartan

An efficient continuous flow process for the synthesis of 5-substituted 1H-tetrazoles is described. The process involves the reaction between a polymer-supported triorganotin azide and organic nitr...

Humic acid as an efficient and reusable catalyst for one pot three-component green synthesis of 5-substituted 1H-tetrazoles in water.

Humic acid is a non toxic, inexpensive, easily available high-molecular weight polymer. A simple and facile one pot three-component synthesis of 5-substituted 1H-tetrazoles from aldehydes, hydroxyamine hydrochloride and sodium azide using humic acid as an efficient catalyst in water is described. The method reported has several advantages such as high to excellent yields, easy work-up, mild reaction conditions, use of water as a green solvent, and a commercially available, nontoxic and reusable catalyst.

TMSN3-Bu2Sn(OAc)2: A modified and mild reagent system for Wittenberger tetrazole-synthesis

Treatments of various nitriles with TMSN3 and Bu2Sn(OAc)2 at 30 °C in benzene for 60 h yielded the corresponding 5-substituted 1H-tetrazoles in good to excellent yields. This method is a mild and efficient alternative reagent system for Wittenberger tetrazole-synthesis that uses TMSN3 and Bu2SnO in toluene at high temperature (93–110 °C) for 24–72 h.

A Facile Approach to Catalyst-Free Cyanation and Azidation of ­Organic Compounds and a One-Pot Preparation of 5-Substituted 1H-Tetrazoles by Using a Dimethyl Sulfoxide–Nitric Acid Combination

In this study, cyanations or azidations of imines were performed by using hydroxy(dimethyl)-λ4-sulfanecarbonitrile or azido(dimethyl)-λ4-sulfanol, respectively, prepared in situ by treatment of potassium cyanide or sodium azide with a dimethyl sulfoxide–nitric acid combination. Furthermore, a one-pot preparation of 5-substituted 1H-tetrazole derivatives was carried out by using this reagent combination in the presence of an aldehyde, hydroxylamine hydrochloride, and sodium azide under mild conditions.

One-Pot Synthesis of 5-Substituted 1H-Tetrazoles on a Silica-Coated Fe3O4-Supported Copper(II) Complex

One-Pot Synthesis of 5-Substituted 1H-Tetrazoles on a Silica-Coated Fe3O4-Supported Copper(II) Complex

A competent green methodology for the synthesis of aryl thioethers and 1H-tetrazole over magnetically retrievable novel CoFe2O4@l-asparagine anchored Cu, Ni nanocatalyst.

The current work describes the successful synthesis of a magnetic CoFe2O4 centered asparagine functionalized noble metal (M = Cu, Ni) anchored nanocomposite. The novel materials, synthesized by post-functionalization approach, have been characterized by XRD, SEM, EDX, X-ray elemental mapping, FT-IR and VSM studies. The materials are proved to be efficient heterogeneous catalyst in the synthesis of diarylthioethers by C-S cross coupling reaction and 5-substituted 1H-tetrazoles by azide-alkyne cycloaddition reaction under green conditions. The current methodology is advantageous in terms of simplicity of procedure, facile synthesis, high yield in short reaction time, easy magnetic isolation and reusability of catalysts in consecutive runs with insignificant change in catalytic activity.

Core–shell nanostructure (Fe3O4@MCM-41@Cu-P2C) as a highly efficient and recoverable nanocatalyst for the synthesis of polyhydroquinoline, 5-substituted 1H-tetrazoles and sulfides

Fe3O4 magnetic nanoparticles were used as a core for Cu(II) Schiff base complex functionalized mesoporous MCM-41 shell to provide a core–shell nanostructure (Fe3O4@MCM-41@Cu-P2C). A simple, environmentally friendly, inexpensive, green reaction conditions and efficient procedure for the synthesis of polyhydroquinoline, 5-substituted 1H-tetrazoles and sulfides derivatives using this core–shell nanostructure as an efficient, novel and recoverable nanocatalyst has been described. Fe3O4@MCM-41@Cu-P2C is stable, cost-effective, heterogeneous, easy to handle and recoverable nanocatalyst and can be reused for several consecutive runs without a significant loss of catalytic activity. The catalyst was characterized by fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), atomic absorption spectroscopy (AAS), Brunauer–Emmett–Teller (BET) and vibrating sample magnetometer (VSM) techniques.

Plant Mediated Green Synthesis, Catalytic Activity and Antibacterial Assay of Silver Nanoparticles

Plant mediated green synthesis of silver nanoparticles (AgNPs) was carried out with the plant extract of Vitex negundo Linn., a simple method without using harmful chemicals. Herein, a root bark extract is used as reducing and capping agent for synthesizing AgNPs from silver nitrate solution. The characterization of AgNPs were obtained by UV-visible spectrophotometer, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The results were confirmed the presence of silver nanoparticles with UV-visible absorption peak at around 433-443 nm and its crystalline nature by XRD analysis. The FTIR spectrum confirmed that the synthesized AgNPs are stabilized and protected by various functional groups of biomolecules in extract. The SEM morphology showed the triangular or spherical shape of AgNPs with the size in the range of 80-100 nm and EDS confirmed the presence of elemental silver in the sample. The catalytic activity of AgNPs was investigated in the synthesis of 5-substituted 1H-tetrazole. Furthermore, antibacterial profile showed that biopotent AgNPs exhibited moderate to good antibacterial activity.

Recent Advances in the Synthesis of 5-Substituted 1H-Tetrazoles: A Complete Survey (2013–2018)

Tetrazoles are synthetic organic heterocyclic compounds comprising of high nitrogen content among stable heterocycles. Tetrazoles, chiefly 5-substituted 1H-tetrazoles have been used as a bioisosteric replacement for carboxylic acids in medicinal chemistry. Various clinical drugs, including losartan, cefazolin, and alfentanil, contain the tetrazole moiety. There have been significant developments in the synthesis of 5-substituted 1H-tetrazoles. Researchers are still working to develop more efficient and ecofriendly methods for their synthesis. In this review, we provide a comprehensive discussion of the recent advancements in the field of synthesis of 5-substituted 1H-tetrazoles.1 Introduction2 The Role of 5-Substituted 1H-Tetrazoles in Medicinal Chemistry3 Synthesis of 5-Substituted 1H-Tetrazoles3.1 Microwave-Assisted Synthesis3.2 Heterogeneous Catalysts3.3 Nanoparticles as Heterogeneous Catalysts3.4 Miscellaneous Methods4 Sartans: A Class of Tetrazole-Based Commercial Drugs5 Conclusions

Copper(II)-faciliated synthesis of substituted thioethers and 5-substituted 1H-tetrazoles: Experimental and theoretical studies

Benzoylhydrazine based Schiff base-ligated two new copper(II) complexes, [Cu(L1)2] (1) and [Cu(L2)2] (2) were synthesized by the reaction of Cu(CH3COO)2·H2O with respective Schiff base ligand 1-[(4-nitrophenyl)ethylidene] benzohydrazide (HL1) or 1-[(4-methoxyphenyl)ethylidene] benzohydrazide (HL2). Both complexes were isolated as greenish solid and fully characterized by elemental analysis, FT-IR, EPR, thermo-gravimetric (TG) analysis and Cyclic Voltammetry. The molecular structures of both complexes have also been determined by single crystal X-ray crystallography, which confirmed the coordination of Schiff base ligands through N, O donor atoms and distorted square planar geometry around the Cu(II) ion. Both complexes were found to be good homogeneous catalysts for the synthesis of a wide range of substituted thioethers and 5-substituted 1H-tetrazoles in 92% and 93% yield, respectively, at a low catalyst loading (0.5 mol%). The bond angles and distances, as discerned from the DFT calculations, commusurated with the experimental findings. The energy difference between the HOMO and the LUMO, calculated from DFT studies, was found to be 5.645 eV and 6.459 eV for complex 1 and complex 2, respectively. These results are in harmony with the observed higher catalytic activity of complex 1.

Anchoring of triethanolamine–Cu(II) complex on magnetic carbon nanotube as a promising recyclable catalyst for the synthesis of 5-substituted 1H-tetrazoles from aldehydes

The development of heterogenization of copper nanoparticles on conductive supports is very challenging and has received much attention. Here, we synthesize a practical, efficient, and inexpensive heterogeneous catalyst to grow stable metallic copper(II) nanoparticles on the surface of magnetic carbon nanotube (Fe3O4-CNT) catalyst support physically functionalized with triethanolamine (TEA) that acts as a low-cost and non-toxic ligand to capture the copper nanoparticles [Fe3O4-CNT-TEA-Cu(II)]. The as-prepared heterogeneous catalyst was characterized by different techniques, such as Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, X-ray diffraction patterns, field-emission scanning electron microscopy, and atomic absorption spectroscopy analysis. The catalytic behavior of Fe3O4-CNT-TEA-Cu(II) was investigated in the preparation of 5-substituted 1H-tetrazole derivatives via one-pot, three-component reaction between aromatic aldehydes, hydroxylamine, and sodium azide. The low catalyst loading, wide substrate scope, use of inexpensive materials, simple separation of the catalyst from the reaction mixture by an external magnet, short reaction times, easy workup, affordability, and superb yield are some advantages of this protocol.