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2022 ◽  
Vol 130 (3) ◽  
pp. 428
Author(s):  
Н.В. Петроченкова ◽  
Т.Б. Емелина ◽  
А.Г. Мирочник

There were studied the luminescent chemosensory properties of Eu(III) carboxylatodibenzoylmethanates with acetic and acrylic acids while the interaction with ammonia vapors. Quantitative measurements of the optical response showed that with an increase in the analyte concentration in the range of 3-330 ppm, a linear increase in the luminescence intensity of europium(III) is observed. The reversibility of the luminescent response was established, the limit of detection of ammonia was 3 ppm. The mechanism of the optical effect is revealed by the method of quantum chemical modeling: the interaction of ammonia with the sensor leads to the formation of a rigid structural fragment of H2O–NH3, which blocks the quenching effect of high-frequency OH vibrations on luminescence. The studied chemosensors have high sensitivity and selectivity and, thus, can be promising for creating ammonia detection sensors for food safety control and environmental monitoring.


Surface ◽  
2021 ◽  
Vol 13(28) ◽  
pp. 75-83
Author(s):  
D. B. Nasiedkin ◽  
◽  
M. O. Nazarchuk ◽  
A. G. Grebenyuk ◽  
L. F. Sharanda ◽  
...  

Метою даної роботи є оцінка енергетичної сприятливості утворення різних молібдатних груп (≡Si‑O‑)2Mo(=O)2 та =Si(‑O‑)2Mo(=O)2 під час термічно ініційованого диспергування MoO3 на гідроксильованій поверхні SiO2. Для цього було здійснено квантовохімічне моделювання реакції O12Si10(OH)16 + MoO3 = O12Si10(OH)14O2MoO2 + H2O в температурному інтервалі 300–1100 K із використанням обмеженого методу Хартрі-Фока (наближення ЛКАО) з валентним базисом SBKJC (Stevens-Basch-Krauss-Jasien-Cundari). Кластер O12Si10(OH)16, який являє собою структурний фрагмент кристала β‑кристобаліту, був використаний як модель високогідроксильованої поверхні кремнезему. Ми розглянули дві структури молібдатних груп (≡Si‑O‑)2Mo(=O)2, прикріплених до кремнеземного кластера O12Si10(OH)16 через силанольні групи. Молібдатні групи (Etot ‑584.60147 Hartree), прикріплені до кремнеземного кластера через віддалені силанольні групи, виявляються більш енергетично вигідними, ніж молібдатні групи (Etot ‑584.56565 Hartree), прикріплені до кремнеземного кластера через сусідні силанольні групи. Енергія молібдатних груп =Si(‑O‑)2Mo(=O)2 (Etot ‑584.48399 Hartree), прикріплених до кремнеземного кластера O12Si10(OH)16 через силандіольні групи, менш енергетично вигідні в порівнянні з подібними групами, прикріпленими через силанольні групи, через більше напруження кута між зв’язками. Знайдено, що реакція O12Si10(OH)16 + MoO3 = O12Si10(OH)14O2MoO2 + H2O в температурному інтервалі 300–1100 K, змодельована шляхом квантовохімічних розрахунків, свідчить, що процес диспергування MoO3 на гідроксильованій поверхні SiO2 є енергетично вигідним. Експ The aim of the present work is to evaluate the energetic favourability of the formation of different molybdate species (≡Si‑O‑)2Mo(=O)2 and =Si(‑O‑)2Mo(=O)2 during the thermally induced MoO3 dispergation on hydroxylated SiO2 surface. In order to do this a quantum chemical modelling of the reaction O12Si10(OH)16 + MoO3 = O12Si10(OH)14O2MoO2 + H2O within the temperature interval of 300–1100 K was undertaken using the Restricted Hartree-Fock method (the LCAO approximation) with the SBKJC (Stevens-Basch-Krauss-Jasien-Cundari) valence basis set. The cluster O12Si10(OH)16 which represents a structural fragment of a β‑cristobalite crystal was used in this work as a model of highly hydroxylated silica surface. We considered two structures of molybdate (≡Si‑O‑)2Mo(=O)2 species attached to O12Si10(OH)16 silica cluster via silanol groups. Molybdate species (Etot ‑584.60147 Hartree) attached to silica cluster via distant silanols appeared more energetically favourable than molybdate species (Etot ‑584.56565 Hartree) attached to silica cluster via nearby silanols. The energy of molybdate =Si(‑O‑)2Mo(=O)2 species (Etot ‑584.48399 Hartree) attached to O12Si10(OH)16 silica cluster via silanediol group is less favourable energetically in comparison with those attached via silanol groups because of higher bond angle straining. The reaction O12Si10(OH)16 + MoO3 = O12Si10(OH)14O2MoO2 + H2O in the temperature interval of 300–1100 K which simulates by quantum chemical calculations the dispergation of MoO3 on hydroxylated SiO2 surface was found to be energetically favourable. The experimentally optimised temperature of ca. 800 K required for dispergation of MoO3 on hydroxylated SiO2 surface is determined by MoO3 evaporation and transportation via the gas phase. ериментальна оптимальна температура (близько 800 K), потрібна для диспергування MoO3 на гідроксильованій поверхні SiO2, визначається випаровуванням та перенесенням MoO3 в газовій фазі.


Antioxidants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Ángel Cores ◽  
Noelia Carmona-Zafra ◽  
Olmo Martín-Cámara ◽  
Juan Domingo Sánchez ◽  
Pablo Duarte ◽  
...  

Curcumin shows a broad spectrum of activities of relevance in the treatment of Alzheimer’s disease (AD); however, it is poorly absorbed and is also chemically and metabolically unstable, leading to a very low oral bioavailability. A small library of hybrid compounds designed as curcumin analogues and incorporating the key structural fragment of piperlongumine, a natural neuroinflammation inhibitor, were synthesized by a two-step route that combines a three-component reaction between primary amines, β-ketoesters and α-haloesters and a base-promoted acylation with cinnamoyl chlorides. These compounds were predicted to have good oral absorption and CNS permeation, had good scavenging properties in the in vitro DPPH experiment and in a cellular assay based on the oxidation of dichlorofluorescin to a fluorescent species. The compounds showed low toxicity in two cellular models, were potent inductors of the Nrf2-ARE phase II antioxidant response, inhibited PHF6 peptide aggregation, closely related to Tau protein aggregation and were active against the LPS-induced inflammatory response. They also afforded neuroprotection against an oxidative insult induced by inhibition of the mitochondrial respiratory chain with the rotenone-oligomycin A combination and against Tau hyperphosphorylation induced by the phosphatase inhibitor okadaic acid. This multitarget pharmacological profile is highly promising in the development of treatments for AD and provides a good hit structure for future optimization efforts.


2021 ◽  
Vol 25 ◽  
Author(s):  
Ashish Patel ◽  
Drashti Shah ◽  
Naiya Patel ◽  
Khushbu Patel ◽  
Nidhi Soni ◽  
...  

: Quinoxaline is a versatile heterocyclic moiety that possesses a wide range of biological activities. Therefore, many researchers have been performing the synthesis of quinoxaline derivatives on a daily basis. In addition, high demands for their synthesis often result in an increased generation of different waste chemicals. However, to minimize the utilization and generation of toxic organic substances, the present review focuses on the various green synthetic approaches for the synthesis of quinoxaline and its derivatives. Moreover, due to the quick manufacturing of novel medications using a quinoxaline scaffold, multiple study reports are published in a short period of time. Therefore, to fully comprehend the current state of the quinoxaline scaffold in medicinal chemistry, it is necessary to combine recent findings with previous understanding. Besides, compared to conventional methods, these green methods minimize the use and generation of harmful chemicals and improve reaction efficiency in terms of product yields, purity, energy consumption, and post-synthetic procedures. Therefore, in this review, we have attempted to shed light on various green synthetic strategies leading to the synthesis of quinoxaline scaffold and its derivatives, such as ultrasound irradiation, microwave irradiation, grindstone technique, environmentally benign solvents/catalysts based, and reactant immobilized on a solid support, etc.


2021 ◽  
Vol 899 ◽  
pp. 628-637
Author(s):  
Daria V. Zakharova ◽  
Zalina A. Lok’yaeva ◽  
Alexander A. Pavlov ◽  
Alexander V. Polezhaev

We present here a small series of compounds designed to modify the polymer chain of various polyurethanes in order to introduce a structural fragment with the ability of thermally-triggered reversible covalent interactions. Bismaleimides (2a-2e) were synthesized from commercially available aromatic and aliphatic symmetric diamines (1a-1e) and were further introduced into the Diels-Alder reaction with furfuryl alcohol as dienophiles. The Diels-Alder adducts (3a-3e) were obtained as a mixture of endo- and exo-isomer. The presence of symmetrical hydroxyl groups in the structure of the obtained compounds makes them suitable as chain extenders of low molecular weight diisocyanate prepolymers. The presence of a thermally reversible Diels-Alder reaction adduct in the structure of potential chain-extenders opens a possibility to create unique materials with self-healing properties. All compounds obtained were characterized by 1H, 13C NMR, ESI-HRMS, and IR spectroscopy. The thermochemical parameters of the reverse Diels-Alder reaction were established using DSC analysis.


Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 427
Author(s):  
Timofey V. Malyarenko ◽  
Alla A. Kicha ◽  
Anatoly I. Kalinovsky ◽  
Pavel S. Dmitrenok ◽  
Olesya S. Malyarenko ◽  
...  

Three new triterpene glycosides, pacificusosides A–C (1–3), and three previously known triterpene glycosides, cucumariosides C1 (4), C2 (5), and A10 (6), were isolated from the alcoholic extract of the Far Eastern starfish Solaster pacificus. The structures of 1–3 were elucidated by extensive NMR and ESIMS techniques and chemical transformations. Compound 1 has a novel, unique structure, containing an aldehyde group of side chains in its triterpene aglycon. This structural fragment has not previously been found in the sea cucumber triterpene glycosides or starfish steroidal glycosides. Probably, pacificusoside A (1) is a product of the metabolism of the glycoside obtained through dietary means from a sea cucumber in the starfish. Another two new triterpene glycosides (2, 3) have closely related characteristics to sea cucumber glycosides. The cytotoxicity of compounds 1–6 was tested against human embryonic kidney HEK 293 cells, colorectal carcinoma HT-29 cells, melanoma RPMI-7951 cells, and breast cancer MDA-MB-231 cells using MTS assay. Compounds 4–6 revealed the highest cytotoxic activity against the tested cell lines, while the other investigated compounds had moderate or slight cytotoxicity. The cytotoxic effects of 2–6 were reduced by cholesterol like the similar effects of the previously investigated individual triterpene glycosides. Compounds 3, 4, and 5 almost completely suppressed the colony formation of the HT-29, RPMI-7951, and MDA-MB-231 cells at a nontoxic concentration of 0.5 µM.


Author(s):  
Ashish Patel ◽  
Drashti Shah ◽  
Naiya Patel ◽  
Khushbu Patel ◽  
Nidhi Soni ◽  
...  

Abstract: The benzimidazole and its derivatives are privileged heterocyclic motif and important building block for the development of the biologically active compound. However, several research reports are produced in a short period of time due to the rapid production of new drugs having a benzimidazole nucleus. In order to understand the current status of the benzimidazole nucleus in medicinal chemistry science, it is therefore important to combine the latest knowledge with earlier information. Hence, synthetic organic chemists concentrated on inventing an effective green methodology for synthesizing benzimidazole derivatives. In addition to this, non-degradable chemical compounds cause the ecosystem to become fragile, damage or irritation as contaminants and pose a danger to the environment. However, conventional methods of synthesis need longer heating time, complicated and tedious apparatus set up which result in high cost and pollution in contrast to greener methods which are inexpensive. In the present review, therefore, we have attempted to shed light on various synthetic strategies leading to the synthesis of different benzimidazole derivatives through the direct condensation reaction between o-phenylenediamine and aromatic aldehydes using green chemistry approaches such as mechanochemistry, ultrasound irradiation, microwave irradiation, environmentally benign solvents/catalysts, reactant immobilized on a solid support and blue light irradiation.


2020 ◽  
Vol 20 (17) ◽  
pp. 1719-1731
Author(s):  
Pavlina Marvanova ◽  
Tereza Padrtova ◽  
Petr Mokry

Aryloxyphenylpiperazinylpropanols are a group of compounds exhibiting a wide range of biological activities, affecting the central nervous system and many cardiovascular mechanisms among them. As cardiovascular agents, aryloxyphenylpiperazinylpropanols work as antihypertensives, antiarrhythmics, cardiotonics or antiaggregants. The mechanism of action is almost always an α1-adrenolytic or combined α1- and β-adrenolytic effect, but sometimes other mechanisms (e.g., Ca2+ antagonism or phosphodiesterase inhibition) antagonism or phosphodiesterase inhibition) can positively participate. In some cases, compounds with a small modification of the connecting chain also exhibit the desired cardiovascular effects. Several studies dealt with chirality of aryloxyphenylpiperazinylpropanols and determined the differences between the particular activities of racemic and enantiomeric compounds.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5228
Author(s):  
Samo Guzelj ◽  
Žiga Jakopin

The dipeptide d-Glu-meso-DAP (iE-DAP) is the minimal structural fragment capable of activating the innate immune receptor nucleotide-binding oligomerization domain protein (NOD1). The meso-diaminopimelic acid (meso-DAP) moiety is known to be very stringent in terms of the allowed structural modifications which still retain the NOD1 activity. The aim of our study was to further explore the chemical space around the meso-DAP portion and provide a deeper understanding of the structural features required for NOD1 agonism. In order to achieve the rigidization of the terminal amine functionality of meso-DAP, isoxazoline and pyridine heterocycles were introduced into its side-chain. Further, we incorporated the obtained meso-DAP mimetics into the structure of iE-DAP. Collectively, nine innovative iE-DAP derivatives additionally equipped with lauroyl or didodecyl moieties at the α-amino group of d-Glu have been prepared and examined for their NOD1 activating capacity. Overall, the results obtained indicate that constraining the terminal amino group of meso-DAP abrogates the compounds’ ability to activate NOD1, since only compound 6b retained noteworthy NOD1 agonistic activity, and underpin the stringent nature of this amino acid with regard to the allowed structural modifications.


2020 ◽  
Vol 64 (10) ◽  
pp. 22-27
Author(s):  
Ljudmila A. Komshina ◽  
◽  
Valentina V. Маrtazova ◽  
Mikhail K. Korsakov ◽  
Irina K. Proskurina ◽  
...  

Sulfonamide derivatives of heterocyclic compounds are promising targets for the search for new substances with specific biological activity. They are widely used as inhibitors of human carbonic anhydrases involved in the implementation of various biochemical processes. The presence of several heterocyclic systems in the structure of sulfonamides significantly increases the ability to bind to active sites of carbonic anhydrases and inhibit their activity. Therefore, the development of approaches to the preparation of sulfonamides of polynuclear heterocyclic compounds is of great scientific interest. This article proposes a multistage scheme for the synthesis and characterization of new sulfonamide derivatives of 1-aryl-6-pyrazol-1-yl-pyridazines. The synthesis of substituted pyrazol-1-yl-pyridazines was carried out by sequential conversion of arylpyridazinones by refluxing in phosphorus oxychloride to 3-chloro-6-arylpyridazines, at the next stage as a result of the nucleophilic substitution of activated chlorine in the pyridazine ring with hydrazine, arylpyridazines were obtained with the reaction Refluxing in butanol, the target compounds with a 3,5-dimethylpyrazole structural fragment were synthesized. The study of the regularities of the course of sulfonylchlorination of 1-aryl-6-pyrazole-1yl-pyridazines made it possible to establish the effect of the substrate structure on the direction of the process and the selectivity of the reaction, as well as on the possibility of the formation of disubstitution products. The corresponding disulfonyl chloride was obtained only in the case of sulfonylchlorination of 1-(4-methoxyphenylpyridazin-3-yl)-3,5-dimethyl-1H-pyrazole at 100 °С for 10 h. In this case, the hydrogen atoms in position 3 of the benzene ring and position 4 of the pyrazole ring. In all other cases, monosubstitution products were obtained at the 4-position of the pyrazole ring. This is evidenced by the data of 1H NMR spectroscopy. On the basis of the obtained sulfonyl chlorides, the corresponding mono- and disulfonamides were synthesized. Convincing proof of the structure of all the obtained compounds has been carried out by a combination of mass spectrometry and NMR spectroscopy data.


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