Solvent-dependent transformations of polysubstituted 2-acetyl-2,5-dihydrothiophenes to the corresponding 2-hydroxy- or deacetylated derivatives are described. The treatment of a methanolic solution of the dihydrothiophene substrates with sodium methoxide afforded the deacylated products. Conversely, the treatment with sodium ethoxide in an oxygen saturated ethanolic solution produced 2-hydroxy substituted 2,5-dihydrothiophenes.

A systematic investigation of the decomposition of substituted 2-(2-azidostyryl)furans has been reported. The products of catalytic decomposition align with predictable patterns, consistent with established literature data. In contrast, photolysis and thermolysis lead to the formation of unexpected products. In this case, generated nitrenes surprisingly exhibited an affinity for the furan core, deviating from the anticipated attack on the olefin moiety.

We investigated the reactivity of various furans towards 2-azidobenzaldehydes, heterocyclic azidoaldehydes, and substituted 2-azidobenzyl alcohols to synthesize 2-(2-azidobenzyl)furan derivatives, revealing the azide group's remarkable compatibility with typical Friedel-Crafts reaction conditions. Additionally, we demonstrated that these derivatives could be efficiently synthesized via a diazotization/azidation sequence from 2-(2-aminobenzyl)furans containing electron-donating substituents, successfully avoiding undesirable side reactions. Furthermore, we developed a synthetic methodology for preparing 2-(2-acylvinyl)indoles, involving the thermal generation of nitrenes to initiate furan ring opening. Notably, our approach utilizes the azidoaryl group and the furan ring separated by a saturated carbon atom that distinguishes it from known indole syntheses in which these moieties are conjugated. The broad applicability and high efficiency of our method, using readily available starting materials, highlight its potential as a versatile synthetic tool.

ABSTRACT It is demonstrated by means of ultra high vacuum (UHV) surface‐sensitive techniques and periodic density functional theory (DFT) calculations that the electronic and NO− adsorption properties of nanosized Ni clusters deposited onto the α‐Al 2 O 3 (0001) surface significantly depend upon the size of the cluster. The properties of the Ni cluster of the size of 2 nm and lower are predominantly determined by the formation of the Ni/Al 2 O 3 interface bond notably polarized towards the oxide. As a result, the metal cluster acquires a net positive charge manifested by the bond strengthening of adsorbed NO compared to the bulk Ni substrate. With the increasing size of the cluster, the Ni/Al 2 O 3 interfacial bond depolarizes due to the growing of lateral Ni–Ni interaction. With a mean coverage of Ni on the alumina surface exceeding 0.25 equivalent monolayers, their properties in terms of adsorption behavior of NO resemble those that are characteristic for the bulk Ni substrate. Such a size dependence offers an opportunity to tune the properties of metal clusters and the metal/oxide system as a whole, for example, to achieve the required electronic and adsorption‐reaction properties.

The sensitivity of field cultures of fungal microbe Aspergillus niger to new synthetic analogs of natural antifungal antibiotics of the isocoumarin class was determined in comparison with antimycotic activity of known drugs. The minimal mycocidal concentration (MMCC) and minimal mycostatic concentration (MMSC) of the drugs were documented. The inhibitory effect (IE) was expressed as the ratio of the average colony diameter of experimental samples to the average colony diameter of control samples. From the results presented in the present work, it follows that the investigated field cultures of Aspergillus niger are most sensitive to antimycotic drugs belonging to N-methylnaphthylmethylamine derivatives and polyene antimycotics — terbinafine (MMSC = 0–2 µg/cm3) and nystatin (MMSC = 4–8 µg/cm3, IE-1 = 1.69, IE-K2 = 1.51), which have a pronounced mycocidal effect. Other studied preparations, including synthesized analogues of natural isocoumarins, showed only mycostatic effect on cultures of fungal microbe Aspergillus niger: fluconazole — MMSC = more than 64 µg/cm3, IE-K1 = 3.38, IE-K2 = 2.52; griseofulvin — MMSC = more than 64 µg/cm3, IE-K1 = 1.79, IE-K2 = 1.53; 3-(3-oxobutyl)-isocoumarin — MMSC = more than 64 µg/cm3, IE-K1 = 1.27, IE-K2 = 1.07; 7-fluoro-3-(oxobutyl)-1-N-isochromene-1-one — MMSC = greater than 64 µg/cm3, IE-K1 = 1.28, IE-K2 = 1.03; (E)-3-(3-oxobutyl-1-en-1-yl)-1-N-isochromene-1-one — MMSC = greater than 64 µg/cm3, IE-K1 = 1.12, IE-K2 = 1.06; 3-(3,3-difluorobutyl)-1-N-iso-chromene-1-one — MMSC = greater than 64 µg/cm3, IE-K1 = 1.34, IE-K2 = 1.25.

With the aim to find out the value of an electronic charge that the Fe atoms acquire when they are doped in Ge bulk, a set of experimental and density functional theory (DFT) studies have been carried out of the model systems consisting of intermixed Fe-Ge films. Such films were prepared by electron and thermal evaporation in ultra-high vacuum (UHV) on the surface of Mo(110) substrate by initial formation of the Ge film of a mean thickness of 75 nm, onto which the Fe films were subsequently deposited, maintaining certain Fe to Ge concentration ratio, namely, 0.2, 04, 0.7 and 1.0. Annealing of such double Fe-Ge films results in notable interdiffusion of the components with quite uniform distribution of the elements throughout the intermixed layer. The details of formation of such layers were in-situ controlled by Auger electron spectroscopy (AES), low-energy ion scattering spectroscopy (LEIS), low-energy electron diffraction (LEED) and work function measurements, in combination with Ar ion depth profiling. By analyzing the Fe Auger LMM-triplet, the absolute values of the charge that Fe atoms acquire when doped in Ge, were estimated for four different Fe-Ge intermixed layers with above-mentioned different Fe to Ge concentration ratio. The corresponding plot of the charge versus Fe to Ge concentration allows to estimate the charge of a single doped Fe atom, which equals to +0.34e (electron charge units) and gradually decreases to 0.07e for high Fe concentration. To verify the experimental values of the Fe charge the calculations were done by periodic DFT as implemented in full-potential FHI-aims code. Among the used algorithms of Mulliken, Hirshfeld, and Bader’s atoms-in-molecules, the latter gives good correlation between charges of Fe dopant and its concentration.

Much synthetic effort is being devoted to the synthesis of fused nitrogen-containing heterocycles. Among them, pyrrolo[1,2- a ]quinoline derivatives continue to gain attention from the synthetic community for decades owing to their diverse biological activities and useful functional properties. Recent advances in the preparation of these prominent heterocycles are summarized in this review.

The Friedel–Crafts reaction of novel 3,5-diarylsubstituted 5-hydroxy-1,5-dihydro-2H-pyrrol-2-ones was used for low cost, one-pot preparation of polycyclic indole derivatives structurally similar to Ergot alkaloids.

Two approaches for the synthesis of substituted phosphonium salts from easily available benzyl alcohols and their heterocyclic analogs have been developed. The developed protocols are complementary: the direct mixing of alcohol, trimethylsilyl bromide, and triphenylphosphine in 1,4-dioxane followed by heating at 80 °C was found to be more efficient for acid-sensitive substrates, such as salicyl or furfuryl alcohols as well as secondary benzyl alcohols, while a one-pot procedure including sequential addition of trimethylsilyl bromide and triphenylphosphine gave higher yields for benzyl alcohols bearing electroneutral or electron-withdrawing substituents.

The catalytic olefination reaction of 2-nitrobenzaldehydes with CF3CCl3 afforded stereoselectively trifluoromethylated ortho-nitrostyrenes in up to 88% yield. The reaction of these alkenes with pyrrolidine permits preparation of α-CF3-β-(2-nitroaryl) enamines. Subsequent one pot reduction of nitro-group by Fe-AcOH-H2O system initiated intramolecular cyclization to afford 2-CF3-indoles. Target products can be prepared in up to 85% yields. Broad synthetic scope of the reaction was shown as well as some followed up transformations of 2- CF3-indole.

2-(2-Acylvinyl)indoles obtained by oxidative rearrangement of substituted 2-(2-aminobenzyl)furans could be used to construct structural analogues of antifungal alkaloids caulindoles A−D as well as other indole-derived molecules and substituted carbazoles by introducing new reaction centers into the structure of starting materials or by synthetic manipulation with functional groups of the obtained compounds.

Исследовано влияние 3-[(е)-3-(3,5-дитрет-бутил-4-гидроксифенил)-3-оксопроп-1-енил]-6-метокси-хромен-4-она в дозах 25, 50, 100, 200 и 400 мг/кг на активность антиоксидантных ферментов (супероксиддисмутазы, каталазы и глутатионпероксидазы), концентрацию продуктов перекисного окисления липидов (ТБК-активные продукты и диеновые конъюгаты) и содержание митохондриального пероксида водорода в головном мозге крыс линии Вистар с фокальной ишемией. Соединение в дозе 50 мг/кг (внутрь, 1 раз в сутки на протяжении 3 дней после моделирования ишемии) повышало активность ферментов эндогенной антиоксидантной защиты в среднем в 2,3 раза (p ≤ 0,05), снижало концентрацию продуктов перекисного окисления липидов в сопоставимой с препаратом сравнения (этилметилгидроксипиридина сукцинат) степени (в среднем в 2 раза, p ≤ 0,05), превосходя при этом последний по степени влияния на уровень митохондриальной перекиси водорода на 28,9 % (p ≤ 0,05). В дозах 25 и 100 мг/кг исследуемое соединение также способствовало восстановлению антиокислительного статуса клеток, тогда как в дозах 200 и 400 мг/кг значимых изменений про/антиоксидантного состояния в головном мозге крыс отмечено не было.

α-CF3-enamines can be prepared by the reaction of pyrrolidine with the corresponding haloalkenes. The prepared enamines react with 2-nitrobenzaldehydes to give ortho-nitro-substituted α,β-diaryl-CF3-enones highly stereoselectively in up to 88% yield. Subsequent reduction of the nitro-group by an Fe-AcOH system promotes intramolecular cyclization to afford 2-CF3-3-arylquinolines in up to 99% isolated yield. High synthetic utility of all synthetic steps of the sequence was shown. A one-pot procedure was developed to give the target trifluoromethylated quinolines directly from enamines or haloalkenes.

The Greater Caucasus is a part of seismically active Alpine–Himalayan orogenic belt and has been a center of significant volcanic activity during the Quaternary period. That led to the formation of the number of hydrothermal habitats, including subterranean thermal aquifers and surface hot springs. However, there are only a limited number of scientific works reporting on the microbial communities of these habitats. Moreover, all these reports concern only studies of specific microbial taxa, carried out using classical cultivation approaches. In this work, we present first culture-independent study of hydrotherms in the Republic of North Ossetia-Alania, located in the southern part of the North Caucasus. Using 16S metabarcoding, we analyzed the composition of the microbial communities of two subterranean thermal aquifers and terrestrial hot springs of the Karmadon valley. Analysis of correlations between the chemical composition of water and the representation of key taxa allowed us to identify the key factors determining the formation of microbial communities. In addition, we were able to identify a significant number of highly abundant deep phylogenetic lineages. Our study represents a first glance on the thermophilic microbial communities of the North Caucasus and may serve as a basis for further microbiological studies of the extreme habitats of this region.

Straightforward method for the synthesis of pyrrolo[1,2-b]cinnolines starting from 2-nitrobenzaldehydes and 2-methylfurans has been elaborated. The key steps of the process are oxidative furan ring opening with diazonium cation and intramolecular alkylation of azo group of the resulted cinnoline with secondary allyl alcohol.

Condensation of 2-naphthol, furfural, and acetamide in the presence of boric acid as acidic catalyst has led to Betti product N-[furan-2-yl(2-hydroxynaphthalen-1-yl)methyl]acetamide along with a new 10,10-dihydrocyclopenta[b]naphtho[1,2-d]furan derivative, which resulted from rare carbo-Piancatelli rearrangement. The structure is confirmed by 1H, 13C NMR, HRMS, and X-ray analyses. Mechanism of the transformation is discussed.

Indolylvinyl ketones are valuable building blocks that can be utilized for the synthesis of numerous natural products and bioactive molecules containing an indole core motif. Herein, we describe their application for the total synthesis of some alkaloids, their analogues, and a variety of other important compounds, with an emphasis on biologically active examples.1 Introduction2 Functionalization of the Enone C=C Bond2.1 Reduction2.2 Michael Addition2.3 Cycloaddition3 Transformation of the Carbonyl Group3.1 Reduction3.2 Knoevenagel Reaction3.3 Addition of Organometallic Compounds3.4 Olefination4 Reactions Involving the Enone Conjugate System С=С–С=О4.1 Reactions with 1,2-Dinucleophiles4.2 Reactions with Compounds Bearing an Active Methylene Group4.3 Reactions with 1,3-Dinucleophiles4.4 Reactions with 1,4-Dinucleophiles5 Functionalization of the Enone Methylene Group C(O)–CH2R5.1 Acylation/Crotonic Condensation and Related Transformations5.2 Enolization6 Functionalization of the Indole Core6.1 [4+2] Cycloaddition6.2 [3+3] Annulation6.3 Electrocyclic Reactions7 Miscellaneous8 Conclusions

The Brönsted acid-catalyzed cascade synthesis of densely substituted benzofurans from easily available salicyl alcohols and biomass-derived furans has been developed. The disclosed sequence includes the intermediate formation of 2-(2-hydroxybenzyl)furans that quickly rearrange into functionalized benzofurans. The established protocol was applied for the total synthesis of sugikurojinol B.

A new facile method for the synthesis of -keto sulfones employing xanthates, DMSO, and Fenton's reagent is described. The reaction proceeds under very mild conditions providing a cost-effective straightforward approach to various -keto sulfones in high yields.