A palladium‐catalyzed enantioselective CH alkylation of pyrroles with diazoesters using axially chiral bipyridine‐N,N′‐dioxide ligands is reported. The transformation provides direct access to enantioenriched pyrrole derivatives under mild conditions and expands the limited repertoire of asymmetric Pd‐catalyzed pyrrole functionalization. Crucially, comparative studies reveal that bipyridine‐N,N′‐dioxide and bipyridine ligands operate through fundamentally different catalytic manifolds. Kinetic analysis, reactivity experiments, and product distribution studies indicate that N‐oxide ligands divert the reaction from a conventional metal‐carbene‐initiated pathway to a mechanism involving electrophilic CH metalation followed by carbene transfer and protonation. These findings demonstrate that subtle ligand modification can alter the mechanistic pathway in Pd‐catalyzed reactions of diazo compounds, paving the way to mechanistically informed strategies for asymmetric CH functionalization of electron‐rich heterocycles.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

AbstractMetal‐catalyzed asymmetric alkylation of indoles with α‐diazoesters is well‐known, however, the underlying mechanisms of this reaction, particularly the origin of stereoselectivity, remain uncertain. For the Pd catalysis, we address this cutting‐edge challenge from two complementary viewpoints – i) the molecular level regarding a single catalytically active Pd center; and ii) nano‐level Pd species investigating the factors favoring the appearance of the preferred catalytic centers. The formation of the active catalytic species was monitored by structural methods (NMR and ESI‐MS), and metal particles were characterized with electron microscopy (SEM, EDX). On the molecular level, chiral bipyridine‐N,N’‐dioxides proved to be competent chiral controllers. The kinetic and DFT computational data revealed a crucial role of water in the rate and selectivity determining steps and showed that the enantioselectivity of the process is controlled by the protodepalladation step. On the nano‐scale, the important effect of catalyst precursor on the overall reaction performance was shown.

E)-5-{[4-(Dimethylamino)benzylidene]amino}-1,3,4-thiadiazole-2(3H)-thione (DATT) was synthesized and its corrosion inhibitive efficiency on mild steel has been investigated in 1 and 5 mol L -1 HCl medium by gravimetric and electrochemical measurements.The structure of DATT was determined by Nuclear Magnetic Resonance (NMR) spectroscopy and Grimme's GFN2-xTB method.The same calculations determined that there are three most stable DATT protomers among mono, double and triple protonated structures.Fukui functions mapped on the van der Waals (vdW) surfaces of DBT and its protonated forms at the PBE0-D3BJ[C-PCM(Water)]/ma-def2-TZVP level of theory was determined.The polarization measurements and analysis of anodic and cathodic slopes of polarization curves have shown that DATT is a mixed-type inhibitor in HCl media in a broad temperature range.Scanning electron microscopy and surface profilometry confirmed the formation of protective films on mild steel surface.The inhibition efficiency of DATT is associated with the protonation of its molecules and increases with concentration of hydrochloric acid solutions when oxygen, sulfur and nitrogen atoms with their single electron pairs bind more easily to the free 3d orbitals of iron.The degree of steel coverage in 5 M HCl is higher than in 1 M acid, according to electrochemical impedance spectroscopy results.Contact angle measurement detected the hydrophobic nature of the steel surface modified by the inhibitor molecules applied in corrosive solutions.The influence of molecular configuration on the corrosion inhibition behavior of (E)-5-{[4-(dimethylamino)benzylidene]dmino}-1,3,4-thiadiazole-2(3H)-thione was explored by quantum chemical calculation and MD simulation.

The design and synthesis of new promising compounds based on thienopyrimidine scaffold containing 2-aminothiophene fragments with good safety and favorable drug-like properties are highly relevant for chemotherapy. In this study, a series of 14 variants of thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives (11aa-oa) and their precursors (31 compounds) containing 2-aminothiophenes fragments (9aa-mb, 10aa-oa) were synthesized and screened for their cytotoxicity against B16-F10 melanoma cells. The selectivity of the developed compounds was assessed by determining the cytotoxicity using normal mouse embryonic fibroblasts (MEF NF2 cells). The lead compounds 9cb, 10ic and 11jc with the most significant antitumor activity and minimum cytotoxicity on normal non-cancerous cells were chosen for further in vivo experiments. Additional in vitro experiments with compounds 9cb, 10ic and 11jc showed that apoptosis was the predominant mechanism of death in B16-F10 melanoma cells. With support from in vivo studies, compounds 9cb, 10ic and 11jc demonstrated the biosafety to healthy mice and significant inhibition of the metastatic nodules in pulmonary metastatic melanoma mouse model. Histological analysis detected no abnormal changes in the main organs (the liver, spleen, kidneys, and heart) after the therapy. Thus, the developed compounds 9cb, 10ic and 11jc demonstrate high efficiency in the treatment of pulmonary metastatic melanoma and can be recommended for further preclinical investigation of the melanoma treatment.

Prenylated polyphenols occur naturally and exhibit biological activity superior to the ubiquitous parent polyphenols.

The present paper is focused on processing of signals from multiple sensors in non-coherent mode that provide improvement of angular resolution of close targets compared to single radar. The low-complexity technique of Direction-of-Arrival (DoA) estimation in Automotive Distributed Non-Coherent Multi-Radar Systems in the case of short length of snapshots is proposed. This technique consists of three main stages: beam-scanning procedure, transformation of the received signals of two radars to the unified coordinate system, and joint DoA estimation algorithm. The DoA method is represented by two approaches: (i) the Capon method modified for joint signal processing; (ii) low-complexity algorithm based on theory of auto-compensator. Performance of the system is investigated on the base of Monte-Carlo simulation. Current algorithm shows improvement of system performance of distributed non-coherent multi-radar systems compared to single radar.

(E)-5-{[4-(Dimethylamino)benzylidene]amino}-1,3,4-thiadiazole-2(3H)-thione (DATT) was synthesized and its corrosion inhibitive efficiency on mild steel has been investigated in 1 and 5 mol L-1 HCl medium by gravimetric and electrochemical measurements. The structure of DATT was determined by Nuclear Magnetic Resonance (NMR) spectroscopy and Grimme's GFN2-xTB method. The same calculations determined that there are three most stable DATT protomers among mono, double and triple protonated structures. Fukui functions mapped on the van der Waals (vdW) surfaces of DBT and its protonated forms at the PBE0-D3BJ[C-PCM(Water)]/ma-def2-TZVP level of theory was determined. The polarization measurements and analysis of anodic and cathodic slopes of polarization curves have shown that DATT is a mixed-type inhibitor in HCl media in a broad temperature range. Scanning electron microscopy and surface profilometry confirmed the formation of protective films on mild steel surface. The inhibition efficiency of DATT is associated with the protonation of its molecules and increases with concentration of hydrochloric acid solutions when oxygen, sulfur and nitrogen atoms with their single electron pairs bind more easily to the free 3d orbitals of iron. The degree of steel coverage in 5 M HCl is higher than in 1 M acid, according to electrochemical impedance spectroscopy results. Contact angle measurement detected the hydrophobic nature of the steel surface modified by the inhibitor molecules applied in corrosive solutions. The influence of molecular configuration on the corrosion inhibition behavior of (E)-5-{[4-(dimethylamino)- benzylidene]dmino}-1,3,4-thiadiazole-2(3H)-thione was explored by quantum chemical calculation and MD simulation.

A short synthesis of N-acetylcolchinol using a greener pathway is reported where all the redox steps, except for the asymmetric reduction, were carried out electrochemically, replacing protocols that employ stoichiometric hazardous reagents.

2-((3-(Ethoxycarbonyl)-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)amino)-4-(4-methoxyphenyl)-4-oxobut-2-enoate has been synthesized by the reaction of ethyl (E)-2-((5-(4-methoxyphenyl)-2-oxofuran-3(2H)-ylidene)amino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate or 2-((3-(ethoxycarbonyl)-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)amino)-4-(4-methoxyphenyl)-4-oxobut-2-enoate with potassium tert-butoxide.

The present paper is focused on the interference mitigation problem for automotive radars in complex signal-interference-noise environments. Current situations are characterized by the fact that cars can be both sources of reflected signals and at the same time interference. Significant number of cars is equipped with radars of the same type (for example, radars with linear frequency modulated signals and with similar parameters). The concept of a two-stage procedure for interference mitigation is proposed. Adaptive beamforming algorithm that constructs a "nulls" in the antenna pattern in the direction of interference sources is developed for the first stage. The second stage is based on the proposed projection method of interference "subtraction" in the frequency domain to eliminate the beat frequencies of interference signals from the spectrum on the "velocity-range" plane. As an example, it is considered the scenario of five targets and one interference source (one of the targets) with the same parameters (linear frequency modulated radars with the same time duration and bandwidth). Numerical simulation results show the high efficiency of the proposed concept.

The hydrolysis of substituted 3-(thien-2-yl)imino-3H-furan-2-ones in the presence of trifluoroacetic acid afforded a series of substituted 4-oxo-2-thienylaminobut-2-enoic acids. Anti-inflammatory activity and acute toxicity of the obtained substituted 4-oxo-2-thienylaminobut-2-enoic acids were studied. It was found that the obtained compounds have a pronounced anti-inflammatory activity and low toxicity.

A method for the synthesis of substituted 4-(het)aryl-4-oxo-2-thienylaminobut-2-enoic acids containing a nitrile substituent in the thiophene ring was proposed. Intramolecular cyclization of the obtained compounds in the presence of propionic anhydride leads to the formation of new substituted 3-thienylimino-3 H -furan-2-ones.

AbstractThe sustained interest in the synthesis of new analogues of 2,2′-bipyridines is supported by the importance of compounds featuring bipyridine core in diverse areas of chemical, biomedical and materials research, which is relayed into the development of new approaches and the expansion of existing synthetic methods. This short review covers advances in the synthesis of 2,2′-bipyridines, including both the synthesis of compounds with a given substitution pattern and the development of new methods for assembling the bipyridine core. Special attention is directed toward the use of pyridine N-oxides and metal-free protocols to facilitate the formation of bipyridines. This short review focuses primarily on reports published in the last 5–6 years.1 Introduction2 Ullmann-Type Homocoupling Reactions3 Cross-Coupling Reactions in the Synthesis of Bipyridines4 Coupling Reactions Employing Pyridine N-Oxides5 Other Methods for the Synthesis of 2,2′-Bipyridines6 Conclusions and Outlook

The synthesis of (E)-2-((3-(ethoxycarbonyl)-5-methyl-4-phenylthiophen-2-yl)amino)-4-oxo-4-(p-tolyl)but-2-enoic acid was performed. This organic compound was used as a building block for the organic molecular crystals with highly stable photoluminescence at ambient conditions, which has been established during 10 years of exploitation.

AbstractAsymmetric crotylation has firmly earned a place among the set of valuable synthetic tools for stereoselective construction of carbon skeletons. For a long time the field was heavily dominated by reagents bearing stoichiometric chiral auxiliaries, but now catalytic methods are gradually taking center stage, and the area continues to develop rapidly. This account focuses primarily on preformed organometallic reagents based on silicon and, to some extent, boron. It narrates our endeavors to design new and efficient chiral Lewis base catalysts for the asymmetric addition of crotyl(trichloro)silanes to aldehydes. It also covers the development of a novel protocol for kinetic resolution of racemic secondary allylboronates to give enantio- and diastereomerically enriched linear homoallylic alcohols. As a separate topic, cross-crotylation of aldehydes by using enantiopure branched homoallylic alcohols as a source of crotyl groups is discussed. Finally, the synthetic credentials of the developed methodology are illustrated by total syntheses of marine natural products, in which crotylation plays a key role in setting up stereogenic centers.1 Introduction2 Pyridine N-Oxides as Lewis Base Catalysts3 Bipyridine N,N′-Dioxides as Lewis Base Catalysts4 Chiral Allylating Reagents5 Synthetic Applications6 Concluding Remarks

Bacterial persistence coupled with biofilm formation is directly associated with failure of antibiotic treatment of tuberculosis. We have now identified 4-(4,7-DiMethyl-1,2,3,4-tetrahydroNaphthalene-1-yl)Pentanoic acid (DMNP), a synthetic diterpene analogue, as a lead compound that was capable of suppressing persistence and eradicating biofilms in Mycobacterium smegmatis. By using two reciprocal experimental approaches - ΔrelMsm and ΔrelZ gene knockout mutations versus relMsm and relZ overexpression technique - we showed that both RelMsm and RelZ (p)ppGpp synthetases are plausible candidates for serving as targets for DMNP. In vitro, DMNP inhibited (p)ppGpp-synthesizing activity of purified RelMsm in a concentration-dependent manner. These findings, supplemented by molecular docking simulation, suggest that DMNP targets the structural sites shared by RelMsm, RelZ, and presumably by a few others as yet unidentified (p)ppGpp producers, thereby inhibiting persister cell formation and eradicating biofilms. Therefore, DMNP may serve as a promising lead for development of antimycobacterial drugs.

Studied the antimicrobial activity against the test cultures of microorganisms St. aureus ATCC 906 and E. coli ATCC 1257 defined by two-fold serial dilutions in a liquid growth medium in a series of substituted 4-aryl-4-oxo-2-tienilaminobut-2-enoic acid. Found that several of the test substances have pronounced antimicrobial activity, and some are at the level of the reference drug dioxidine. Also analyzed acute toxicity (LD50, mg/ml) in white mice (females) weighing 16-18 g. after a single intraperitoneal injection for all the compounds obtained and found that they are practically non-toxic 5 class of drugs.

The design of catalysts for asymmetric propargylations remains a challenging task, with only a handful of methods providing access to enantioenriched homopropargylic alcohols. In this work, guided by previously reported computational predictions, a set of atropisomeric bipyridine N,N'-dioxides was tested as Lewis base catalysts for the asymmetric propargylation of aldehydes with trichloroallenylsilane. The catalysts are easily prepared in four simple steps starting from readily available methyl ketones. Aryl-substituted derivatives proved to be highly active and showed a high level of enantiocontrol even at 1 mol% loading. The reaction scope includes a wide range of aromatic, heteroaromatic, and unsaturated aldehydes. New computations confirm that the key stereodetermining transition state structures for the synthesized catalysts are similar to those previously reported for the model structure.