Strategies for synthesis of 1,2,4-triazole-containing scaffolds using 3-amino-1,2,4-triazole

Molecular Diversity - 1,2,4-Triazole-containing scaffolds are unique heterocyclic compounds present in an array of pharmaceuticals and biologically important compounds used in the drug-discovery...     

Molecular docking studies,biological evaluation and synthesis of novel 3-mercapto-1,2,4-triazole derivatives

Molecular Diversity - Synthesis of bioactive heterocyclic compounds having effective biological activity is an essential research area for wide-ranging applications. In this study, a conventional...     

Quadrupole hyperfine structure of the microwave spectrum of 1,2,4-triazole and N-deuterotriazole

We report the analysis of the hyperfine structure in the microwave spectrum of 1,2,4-Triazole. Principal quadrupole coupling constants at each of the three inequivalent ¹⁴N nuclei have been obtained.     

Synthesis and insecticidal activity of novel 1,2,4-triazole derivatives containing trifluoroacetyl moieties

Molecular Diversity - A series of compounds containing trifluoroacetyl groups were synthesized, and their insecticidal activity against Nilaparvata lugens and Aphis craccivora was evaluated. The...     

Design and synthesis of benzodiazepine-1,2,3-triazole hybrid derivatives as selective butyrylcholinesterase inhibitors

Molecular Diversity - A new series of compounds based on benzodiazepine-1,2,3-triazole were synthesized and evaluated as cholinesterase inhibitors by Ellman’s method. The compounds proved to...     

Design and exploration of 5-nitro-3-trinitromethyl-1H-1,2,4-triazole and its derivatives as energetic materials

Molecular Diversity - According to the fact that 5-nitro-3-trinitromethyl-1H-1,2,4 triazole (NTNMT) is a successful, good explosive, energetic groups such as –CH3, –NH2, –NHNO2,...     

Manipulation of ultracold atomic mixtures using microwave techniques

We used microwave radiation to evaporatively cool a mixture of of ¹³³Cs and ⁸⁷Rb atoms in a magnetic trap. A mixture composed of an equal number (around 10⁴) of Rb and Cs atoms in their doubly polarized states at ultracold temperatures was prepared. We also used microwaves to selectively evaporate atoms in different Zeeman states.     

Novel 1,2,4-triazole analogues as mushroom tyrosinase inhibitors: synthesis,kinetic mechanism,cytotoxicity and computational studies

Molecular Diversity - We have created a novel series of mushroom tyrosinase inhibitors with 1,2,4-triazole as fundamental skeleton. The target compound 1,2,4-triazol-3-ylthio)-N-phenyl acetamide...     

Understanding the adsorption of 4H-1,2,4-triazole derivatives on mild steel surface in molar hydrochloric acid

This study examines the use of some 4H-triazole derivatives, namely 3,5-diphenyl-4H-1,2,4-triazole (DHT), 3,5-bis(4-pyridyl)-4H-1,2,4-triazole (4-PHT) and 3,5-bis(4-methyltiophenyl)-4H-1,2,4-triazole (4-MTHT) for corrosion and dissolution protection of mild steel in normal hydrochloric acid solution. The inhibiting efficiency of the different additives is evaluated by means of weight loss and electrochemical techniques such as ac impedance measurements and polarisation curves. The experimental results obtained reveal that 4-MTHT is the best effective inhibitor and the inhibition efficiency is found to be in the following order: 4-MTHT > 4-PHT > DHT. The variation in inhibitive efficiency mainly depends on the type and nature of the substituents present in the inhibitor molecule. Polarisation curves show that theses triazoles are mixed-type inhibitors in 1 M HCl. The inhibition efficiency increases with 4H-triazole derivatives concentration and attains the maximum value of 99.6% in the case of 4-MTHT at 5 × 10⁻⁴ M. The results obtained from weight loss electrochemical studies were in reasonable agreement. The adsorption of 4H-triazole derivatives on the steel surface obeys to the Langmuir isotherm model. The thermodynamic data of adsorption and activation are determined and discussed. The fundamental thermodynamic functions were used to glean important information about the 4H-triazoles inhibitory behaviour. Molecular modeling was used to get better insight, about structural and electronic effects in relation to the inhibition efficiencies.     

Nuclear quadrupole coupling in the microwave spectrum of 1,2,3-triazole

The hyperfine structure in the microwave spectra of 1,2,3-triazole and N-deutero 1,2,3-triazole has been analyzed. The coupling constants derived from the analysis of each isotopic species have been combined to give the principal nuclear quadrupole coupling constants at the sites of the three inequivalent ¹⁴N nuclei.     

Ultrasound and microwave assisted synthesis of dihydroxyacetophenone derivatives with or without 1,2-diazine skeleton

A thorough study concerning O-alkylation and α-bromination of dihydroxyacetophenone (DA) and N-alkylation of 1,2-diazine, under ultrasound (US) and microwave (MW) irradiation as well as under conventional thermal heating (TH) is presented. Under US and MW irradiation the yields are higher, the amount of used solvent decreases substantially, the reaction time decreases considerable (from hours or days to minutes) and the consumed energy decreases, consequently the O-alkylation, α-bromination and N-alkylation methods could be considered environmentally friendly. A selective and efficient way to either bis-O-alkylation or mono-O-alkylation of DA has been found, the relative position of the two hydroxyl groups on the phenyl moiety being compulsory. A selective and efficient way for α-bromination in heterogeneous catalysis of DA derivatives under US irradiation is presented. The N-alkylation reaction of DA under US and MW irradiation proved to be the most convenient setup procedure for these types of reactions. Overall, the use of US proved to be more efficient than MW or TH.     

Dielectric studies of some binary liquid mixtures using microwave cavity techniques

The excess parameter studies in the microwave frequency region (X-band) on complex dielectric permittivity for the binary mixtures are reported. The methods employed are fixed cavity perturbation technique and adjustable plunger cavity technique. Also Gopalakrishna method is used to calculate the relaxation time of the polar solute in a non-polar solvent. The samples under study are acetonitrile, chlorobenzene, dimethyl formamide, carbon tetrachloride and benzene.     

Analysis of microwave propagation effects using two-dimensional electrooptic field mapping techniques

In high-speed electronic devices and monolithic microwave and millimetrewave integrated circuits the propagation of electromagnetic waves plays an important role. In so-called travelling wave devices and circuits these propagation effects are applied to design and realize functions not available in lumped elements. In order to exploit fully the potential of wave propagation effects, experimental investigations have to be carried out which, however, require a measurement technique to allow spatially resolved detection of microwave potential or field distributions inside elements and circuits and along the electrical interconnects. In this paper, it is shown by several examples, that the two-dimensional electrooptic field mapping technique is an excellent tool to study wave propagation effects up to millimetrewave frequencies, with submicrometre spatial resolution and without electromagnetic interference.     

A study of the synthesis of triazoles using microwave irradiation

Herein we describe the conversion of a known [3+2] cycloaddition reaction between an azide and an acetylene from a thermally promoted reaction to a microwave assisted process. Modification of conditions including concentration, temperature, solvent type and time were investigated. This methodology study led us to use high concentration and high temperatures to achieve the desired fast reaction times and high yields.     

Efficient library synthesis of imidazoles using a multicomponent reaction and microwave irradiation

Optimization of Radziszewski's four-component reaction employing a microwave-assisted protocol, led to a small library of 48 imidazoles with a success rate of 65% (conversion > 45%). All three diversity points of the four-component reaction were varied. Aromatic and aliphatic inputs were successfully implemented and mono-, di-, tri- and tetrasubstituted imidazoles with various substitution patterns were synthesized. Furthermore, unsymmetrical diketones could successfully be used which improved the intrinsic diversity of the method significantly. If the unsymmetrical diketone 1,2-phenylpropanedione (R¹ and R²) was used two regioisomers were formed. Depending on the type of amine (R⁴) and aldehyde (R³) applied, regioselectivity was modest to good. Based on these results, a reaction mechanism is proposed.     

Rapid synthesis and characterization of silicon substituted nano hydroxyapatite using microwave irradiation

Nano sized hydroxyapatites with silicon substitution of three different silicon concentrations were successfully prepared first time by a rapid microwave assisted synthesis method, with a time saving and energy efficient technique. The effects of the Si substitution on crystallite size, particle size and morphology of the powders were investigated. The crystalline phase, microstructure, chemical composition, and morphology and particle size of hydroxyapatite and silicon substituted hydroxyapatites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and dynamic light scattering. The crystallite size and particle size decreases with increase in silicon content and particle morphology spheroidal for pure hydroxyapatite changes to elongated ellipsoidal crystals while silicon substitution increases. Fourier Transform Infrared Spectroscopy analysis reveals, the silicon incorporation to hydroxyapatite lattice occurs via substitution of silicate groups for phosphate groups. Substitution of phosphate group by silicate in the apatite structure results in a small increase in the lattice parameters in both a-axis and c-axis of the unit cell.     

Two-dimensional field mapping of monolithic microwave integrated circuits using electrooptic sampling techniques

Since the invention of the electrooptic sampling technique about ten years ago, this contactless test technique based on ultra-short optical pulses has become more and more attractive to microwave engineers developing monolithic microwave integrated circuits (MMICs). The electrooptic sampling technique was originally used for circuit internal measurements of very high-speed waveforms only at discrete test points. During the last five years, a new test technique, the two-dimensional electrooptic field mapping technique, has been developed and widely used. This test technique which measures the magnitude and phase of the microwave signal gives information not only of one discrete test point but also of a greater area within the circuit and therefore insight into the microwave field distribution. This two-dimensional electrooptic field mapping technique could be a powerful tool for studying fundamental properties of wave propagation in monolithic integrated microwave devices and circuits. The aim of this paper is to present the state-of-art of this new test technique and to show an example of its application.     

Coordination preference and magnetic properties of FeII assemblies with a bis-azole bearing 1,2,4-triazole and tetrazole

With a new bis-azole molecular fragment (Htt) bearing 1,2,4-triazole and tetrazole, a mononuclear complex [Fe(tt)₂(H₂O)₄]·2H₂O (1), a trinuclear complex [Fe₃(tt)₆(H₂O)₆]·2H₂O (2) and a 1D coordination polymer [Fe(tt)(Htt)₂]BF₄·2CH₃OH (3) were obtained by varying reaction conditions. Htt acts either as an anionic or neutral ligand depending upon the reaction medium and pH. Thermal variation of spin states of 1–3 were investigated in the range 77–300?K by ⁵⁷Fe M?ssbauer spectroscopy. 1 totally remains in high-spin state over the entire temperature range whereas no spin crossover was evidenced in 2. Nearly 1:1 high-spin and low-spin population ratio is found in 3, which remains constant over the entire temperature range investigated.