The Reactions of N,N'-Diphenyldithiomalondiamide with Arylmethylidene Meldrum's Acids

The Michael addition reaction between dithiomalondianilide (N,N'-diphenyldithiomalondiamide) and arylmethylidene Meldrum's acids, accompanied by subsequent heterocyclization, was investigated along with factors affecting the mixture composition of the obtained products. The plausible mechanism includes the formation of stable Michael adducts which, under the studied conditions, undergo further transformations to yield corresponding N-methylmorpholinium 4-aryl-6-oxo-3-(N-phenylthio-carbamoyl)-1,4,5,6-tetrahydropyridin-2-thiolates and their oxidation derivatives, 4,5-dihydro-3H-[1,2]dithiolo[3,4-b]pyridin-6(7H)-ones. The structure of one such product, N-methylmorpholinium 2,2-dimethyl-5-(1-(2-nitrophenyl)-3-(phenylamino)-2-(N-phenylthiocarbamoyl)-3-thioxopropyl)-4-oxo-4H-1,3-dioxin-6-olate, was confirmed via X-ray crystallography.

Oxidation of 2-Cyanothioacrylamides with Sodium Nitrite in Acidic Medium

Abstract

(E)-3-Aryl-2-cyanoprop-2-entioamides, prepared by Knoevenagel condensation between aromatic aldehydes and cyanothioacetamide, react with sodium nitrite in acetic acid to form (2E,2′E)-2,2′-(1,2,4-thiadiazole-3,5-diyl)bis[3-arylacrylonitriles]. A possible mechanism and limitations of the reaction are discussed. Molecular docking was carried out in order to search for possible protein targets for the obtained 1,2,4-thiadiazoles. One of the compounds showed a pronounced antidote effect against the herbicide 2,4-D in a laboratory experiment on sunflower seedlings and under field conditions.

N,N'-Diphenyldithiomalonodiamide: Structural Features, Acidic Properties, and In Silico Estimation of Biological Activity

The spectral characteristics of dithiomalondianilide (N,N'-diphenyldithiomalonodiamide) were studied, and the dissociation constant was determined by potentiometric titration. Quantum-chemical methods at the B3LYP-D3BJ/6-311+G (2d,p) level were used to calculate the molecular geometry and vibrational spectra of the most stable tautomeric forms of dithiomalondianilide. The bioavailability parameters were calculated, and possible protein targets were predicted by the protein ligand docking method.

F. A review on the development of urease inhibitors as antimicrobial agents against pathogenic bacteria

Ureases are enzymes that hydrolyze urea into ammonium and carbon dioxide. They have received considerable attention due to their impacts on living organism health, since the urease activity in microorganisms, particularly in bacteria, are potential causes and/or factors contributing to the persistence of some pathogen infections. This review compiles examples of the most potent antiurease organic substances. Emphasis was given to systematic screening studies on the inhibitory activity of rationally designed series of compounds with the corresponding SAR considerations. Ureases of Canavalia ensiformis, the usual model in antiureolytic studies, are emphasized. Although the active site of this class of hydrolases is conserved among bacteria and vegetal ureases, the same is not observerd for allosteric site. Therefore, inhibitors acting by participating in interactions with the allosteric site are more susceptible to a potential lack of association among their inhibitory profile for different ureases. The information about the inhibitory activity of different classes of compounds can be usefull to guide the development of new urease inhibitors that may be used in future in small molecular therapy against pathogenic bacteria.

A direct green route towards the synthesis of 2-aroyl-3,5-diarylthiophenes from 1,5-diketones

The synthesis of 2-aroyl-3,5-diarylthiophenes has been achieved from various 1,5-diketones with elemental sulphur and morpholine under microwave irradiation following a greener protocol.

Solvent and structural effects on the UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides

UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides have been recorded in the range 200-400 nm in the set of selected solvents. The solute-solvent interactions were analyzed on the basis of linear solvation energy relationships (LSER) concept proposed by Kamlet and Taft. The effects of substituents on the absorption spectra were interpreted by correlation of absorption frequencies with Hammett substituent constant, σ. It was found that substituents significantly change the extent of conjugation. Furthermore, the experimental findings were interpreted with the aid of ab initio B3LYP/6-311G(d,p) method. Electronic energies was calculated by the use of 6-311++G(3df,3pd) methods with standard polarized continuum model (PCM) for inclusion of the solvent effect.

Synthesis and luminescent properties and theoretical investigation on electronic structure of nitrile-based 2-pyridone molecules

3-Cyano-4,6-dimethyl-2-pyridone and 3-cyano-4-methyl-6-phenyl-2-pyridone were synthesized effectively by the reaction of readily available 1,3-diketone and malononitrile directly and in good yield. Upon photoexcitation, 3-cyano-4-methyl-6-phenyl-2-pyridone in ethanol shows strong blue emission. The ground- and excited-state geometries, charge distributions, and excitation energies of 2-pyridone derivatives were evaluated by ab initio calculations. Organic light-emitting diodes (OLED) made using 3-cyano-4-methyl-6-phenyl-2-pyridone as dopant showed blue light emission with a maximum electroluminescence (EL) emission at around 456 nm.

Acyclic selenoiminium salts: isolation, first structural characterization, and reactions

[reaction: see text] A variety of selenoiminium salts were obtained by reacting the corresponding selenoamides with methyl triflate at room temperature for 30 s. All of the salts were stable under air. The structures of the selenoiminium salts were determined by X-ray molecular analysis. An aromatic selenoiminium salt reacted with BuLi (3 equiv) to give two types of ketones. In a reaction with LiAlH(4)/Te, the selenoiminium salts were converted to telluroamides.