AlCl3as an Effective Lewis Acid for the Synthesis of Arylaminotetrazoles

Catalytic Tetrazole Synthesis via [3+2] Cycloaddition of NaN3 to Organonitriles Promoted by Co(II)-complex: Isolation and Characterization of a Co(II)-diazido Intermediate

The [3+2] cycloaddition of sodium azide to nitriles to give 5-substituted 1H-tetrazoles is efficiently catalyzed by a Cobalt(II) complex (1) with a tetradentate ligand N,N-bis(pyridin-2-ylmethyl)quinolin-8-amine. Detailed mechanistic investigation shows the intermediacy of the cobalt(II) diazido complex (2), which has been isolated and structurally characterized. Complex 2 also shows good catalytic activity for the synthesis of 5-substituted 1H-tetrazoles. These are the first examples of cobalt complexes used for the [3+2] cycloaddition reaction for the synthesis of 1H-tetrazoles under homogeneous conditions.

Tetrazoles as anticancer agents: A review on synthetic strategies, mechanism of action and SAR studies

Cancer is a leading cause of death worldwide. Even after the availability of numerous drugs and treatments in the market, scientists and researchers are focusing on new therapies because of their resistance and toxicity issues. The newly synthesized drug candidates are able to demonstrate in vitro activity but are unable to reach clinical trials due to their rapid metabolism and low bioavailability. Therefore there is an imperative requisite to expand novel anticancer negotiators with tremendous activity as well as in vivo efficacy. Tetrazole is a promising pharmacophore which is metabolically more stable and acts as a bioisosteric analogue for many functional groups. Tetrazole fragment is often castoff with other pharmacophores in the expansion of novel anticancer drugs. This is the first systematic review that emphasizes on contemporary strategies used for the inclusion of tetrazole moiety, mechanistic targets along with comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency tetrazole-based anticancer drug candidates.

An intramolecular relay catalysis strategy for Knoevenagel condensation and 1,3-dipolar cycloaddition domino reactions

A relay catalysis strategy was established by using a bifunctional catalyst which was prepared by immobilization of organic chains containing secondary amine and Cu(ii) complex onto silica-coated nano-Fe₃O₄. The simply prepared nanoparticles acted as efficient, intramolecular relays and magnetically recyclable base-metal bifunctional catalysts for Knoevenagel condensation and 1,3-dipolar cycloaddition domino reactions to prepare 5-substituted 1H-tetrazoles with excellent yields.

A magnetically recoverable bifunctional catalyst was synthesized and effectively used in Knoevenagel condensation and 1,3-dipolar cycloaddition domino reactions.

Green synthesis of Ag/Fe(3)O(4) nanocomposite using Euphorbia peplus Linn leaf extract and evaluation of its catalytic activity

In this work, the Ag/Fe₃O₄ nanocomposite was prepared by Euphorbia peplus Linn (L.) leaf extract as a suitable reducing source and stabilizing agent. The green synthesized nanocomposite was characterized using X-ray diffraction analysis (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) images, energy-dispersive X-ray spectroscopy (EDS) and FT-IR spectroscopy. TEM analysis of Ag/Fe₃O₄ nanocomposite showed the spherical shape nanoparticles (NPs) with an average size of 5-10nm. The Ag/Fe₃O₄ nanocomposite then was used as a magnetically recoverable catalyst for the [2+3] cycloaddition of arylcyanamides and sodium azide in high yields and short reaction times without formation of hydrazoic acid (HN₃). Also it can be easily recovered via applying of external magnetic field and reused several times without significant loss of activity.

High Catalytic Activity of Peptide Nanofibres Decorated with Ni and Cu Nanoparticles for the Synthesis of 5-Substituted 1H-Tetrazoles and N-Arylation of Amines

A rapid development of a new methodology for decarboxylative N-arylation of carboxylic acids and the preparation of 5-substituted 1H-tetrazoles catalysed by peptide nanofibres decorated with Cu and Ni nanoparticles is presented. Compared with conventional aryl halides, benzoic acids are extremely interesting and environmentally friendly options for the synthesis of secondary aryl amines.

Application of a functionalized mesoporous silica catalyst to the synthesis of tetrazoles

Highly ordered MCM-41 was synthesized and functionalized with benzylic groups. The solid catalyst was used in the synthesis of aryl tetrazoles.

Copper Iodide Nanoparticles-Catalysed Cyanation of Aryl Halides Using Non-Toxic K4[Fe(CN)6] in the Presence of 1,2-Bis(5-Tetrazolyl)Benzene as an Efficient Ligand

Cyanation of aryl bromides were carried out with K4[Fe(CN)6] in the presence of catalytic amounts of a copper salt and 1,2-bis(5-tetrazolyl)benzene as a ligand under thermal conditions. This method has the advantages of high yields, simple methodology and easy work up.

CoFe2O4 Nanoparticles as a Magnetically Recoverable and Reusable Catalyst for the Synthesis of Arylaminotetrazoles and 5-aryloxytetrazoles

An efficient and direct method is described for the synthesis of 5-arylamino-1 H-tetrazoles (Isomer A) or 1-aryl-5-amino-1 H-tetrazoles (Isomer B) and 5-aryloxytetrazoles from arylcyanamides or cynates with nano CoFe2O4 as a reusable and efficient heterogeneous catalyst. Isomer A was obtained from arylcyanamides carrying electron-withdrawing substituents on the aryl ring, while isomer B was produced with electron-releasing groups. The significant advantages of this methodology are high yields, elimination of dangerous and harmful hydrazoic acid, simple work-up procedure and the recovery and reusability of the catalyst.

Electrochemical and DFT study on the inhibition of 316L stainless steel corrosion in acidic medium by 1-(4-nitrophenyl)-5-amino-1H-tetrazole

This article describes the best corrosion inhibition behavior and adsorption of newly synthesized amino tetrazole using electrochemical and computational methods.

Solvent-Free Synthesis of 1-Aryl-1H-1,2,3,4-Tetrazoles using FeCl3–SiO2 Catalysis under Conventional and Ultrasound Irradiation Conditions

1-Aryl-1 H-1,2,3,4-tetrazoles were synthesised by the solvent-free reactions of aryl amines, sodium azide and triethyl orthoformate using FeCl3–SiO2 as an effective heterogeneous catalyst under conventional and ultrasound irradiation conditions. This method has the advantages of high yields, simple methodology and easy work-up. The catalyst can be recovered by simple filtration and reused delivering good yields.

Acetylation of Phenols, Anilines, and Thiols Using Silica Sulfuric Acid under Solvent-Free Conditions

Silica sulfuric acid was employed as a heterogeneous catalyst for the acetylation of a variety of phenols, amines, and thiols under solvent-free conditions at room temperature. Deactivated substrates also acetylated rapidly, and the method showed the preferential selectivity for acetylation of amino group in the presence of hydroxyl groupinwhich no C-acylation was observed.

Silica Sulfuric Acid as an Efficient Heterogeneous Catalyst for the Solvent-Free Synthesis of 1-Substituted 1H-1,2,3,4-Tetrazoles

Silica sulfuric acid (SSA) was found to be an efficient heterogeneous catalyst for the synthesis of 1-substituted 1H-1,2,3,4-tetrazoles from the reaction of primary amines with triethyl orthoformate and sodium azide under thermal and solvent-free conditions.

N-Formylation of Anilines with Silica Sulfuric Acid under Solvent-Free Conditions

N-formylation of primary and secondary amines was carried out with formic acid in the presence of silica sulfuric acid under solvent-free conditions to give the corresponding formamides in excellent yield and short reaction times.

Diphenylphosphinoethane-functionalized polystyrene resin-supported Pd(0) complex — A highly active and recyclable catalyst for the Stille reaction under aerobic conditions

The polymer-supported palladium(II) diphenylphosphinoethane complex is a highly active catalyst that could be used for the Stille coupling reaction between aryl iodides and (or) chlorides and organostannanes at room temperature under aerobic conditions. This heterogeneous palladium catalyst is efficient, air-stable, and recyclable.