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Bismuth halide perovskites have emerged as promising alternatives for sustainable and efficient photocatalysts for light‐induced organic transformations. Caesium bismuth halide perovskites (Cs3Bi2(ClxBr1‐x)9) with different ratios of chloride and bromide were synthesised using a one‐step solution process. These perovskites were then employed as photocatalysts for the photocatalytic oxidative coupling of benzylamine (BZA) to produce N‐benzylidenebenzylamine (BZI) under ultraviolet‐visible light radiation at ambient conditions. The incorporation of bromide ions into the chloride‐based perovskite resulted in a noticeable reduction in the bandgap, leading to an enhancement in the photocatalytic activity. Conversely, the addition of chloride ions within the bromide‐based perovskite was found to be beneficial for the material's photostability while simultaneously maintaining its high photocatalytic activity. The optimal compromise between the stability and photocatalytic activity for the BZI production was achieved using Cs3Bi2(Cl0.8Br0.2)9, being attained a total BZA conversion and the maximum BZI production with 100 % of selectivity after 6 hours of irradiation. The efficiency of this photocatalyst was ascribed to the highest current density observed during the photocurrent experiments, which improves the charge carrier mobility of the resulting material. [ABSTRACT FROM AUTHOR]

Bengamide E is a bioactive natural product that was isolated from Jaspidae sponges by Crews and co-workers in 1989. It displays a wide range of biological activities, including antitumor, antibiotic, and anthelmintic properties. With the aim of investigating the structural feature essential for their activity, several total syntheses of Bengamide E and its analogues have been reported in the literature. Nevertheless, no synthesis of the stereoisomer with modification of its configuration at C-4 carbon has been reported so far. Here, we report the first total synthesis of the 4-epi-Bengamide E. Key reactions in the synthesis include a chemoenzimatic desymmetrization of biobased starting materials and a diastereoselective Passerini reaction using a chiral, enantiomerically pure aldehyde, and a lysine-derived novel isocyanide. [ABSTRACT FROM AUTHOR]

Due to amine derivatives widely existing in numerous clinical medicines and bioactive compounds, their synthesis has received considerable attention over the past few decades. Traditional methods for the synthesis of amine derivatives largely relied on the reduction of nitroarenes, amides, hydrazines, nitriles, and azides. Recently, the discovery of 2‐azaallyl anions as super‐electron‐donors (SEDs) has opened up new possibilities for the construction of diverse carbon‐carbon and carbon‐heteroatom bonds through radical coupling strategies. This breakthrough highlights the potential of generating 2‐azaallyl radicals as versatile intermediates in organic synthesis. Then, hydrolysis of the coupling product can easily separate the corresponding amine derivatives. Thus, tremendous attention has been paid to the C−H functionalization of ketimines as an alternative strategy for the synthesis of amine derivatives. Herein, we comprehensively summarize the recent progress in radical coupling strategies enabled by 2‐azaallyl anions as SEDs. Their proposed mechanistic pathways, advantages, and limitations are also discussed in detail. 1. Introduction 2. C−C Bond Formation 2.1. Vinylation of Ketimines 2.2. Arylation of Ketimines 2.3. Alkylation of Ketimines 2.3.1. Methylation of Ketimines 2.3.2. Other Alkylation of Ketimines 3. C−X Bond Formation 3.1. C−P and C−S Bonds Formation 3.2. C−N and C−O Bonds Formation 4. Conclusions [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published in 2024. It includes various articles on topics such as enantioselective merged gold/organocatalysis, the influence of ion and hydration atmospheres on RNA structure and dynamics, NMR analysis of labeled naphthyridine carbamate dimer, and the synthesis of sydnonimines from sydnones. The journal aims to connect the world with the chemical sciences and is published by The Royal Society of Chemistry. [Extracted from the article]

A palladium-catalyzed enantioselective umpolung allylation reaction of amido-tethered allyl carbonates with N-2,2,2-trifluoroethylisatin ketimines has been realized herein. The reaction worked well under mild reaction conditions to give various chiral oxindole derivatives in moderate to excellent yields with high enantioselectivities. Notably, this work represents the first Pd-catalyzed asymmetric umpolung allylation reaction of N-2,2,2-trifluoroethylisatin ketimines. [ABSTRACT FROM AUTHOR]

Dibenzoazepine, dibenzoxazepine and dibenzothiazepine scaffolds are an important class of N‐heterocycles that possess multiple biological activities. Due to the widespread application of these motifs in drug discovery, the synthesis of tri‐cyclic seven‐membered imines/amines has gained huge attention of chemists. In the present review, we have highlighted recent advances in functionalization and cyclization reactions of these valuable organic compounds over the last six years. [ABSTRACT FROM AUTHOR]

In this contribution, new derivatives of bicyclic fused rings with a bridgehead nitrogen atom were synthesized from the imidazo[1,2-a]pyridine derivatives C1 by reacting two moles of 2-aminopyridine and 4-aminoacetophenone with iodine in a one-pot reaction. This compound (C1) was then condensed with 2- nitrobenzaldehyde and 2,4-dichlorobenzaldehyde to form new derivatives of Schiff bases (C2 and C3). These Schiff bases were then cyclized to synthesize thiazolidin4-one derivatives (C4 and C5), tetrazole derivatives (C6 and C7), and aza-β-lactam derivatives (C8 and C9) through the reactions with thioglycolic acid, sodium azide, and 1-naphthylisocyanate, respectively. FT-IR, 1H NMR, and 13C NMR spectroscopy were used to characterize these new compounds. In the second part of this work, the antioxidants of these compounds were measured, and results ranged from good to medium. [ABSTRACT FROM AUTHOR]

This study looked into the high yield production of new spiropyrrolooxindole derivatives. In order to create these new compounds, a multicomponent reaction involving isatin, malononitrile, alkyl 2,4-dioxo-4-(arylamino) butanoate derivatives, primary amines, and ethyl bromopyruvate was carried out in water at room temperature with catalytic amounts of Ag@KF/CP NPs acting as a high performance catalyst. The antioxidant property of new synthesized spiropyrrolooxindoles are owing to having NH group which was evaluated by two procedures. Also, the antimicrobial activity of new generated spiro isatins was evaluated by disk distribution process utilizing two kinds of Gram-negative bacteria and Gram-positive bacteria; proving bacterial growth was stopped by using of these compounds. Also, the catalytic activity of the green synthesized Ag@KF/CP NPs was evaluated in the reduction of organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for organic pollutants within few seconds. Applied to the preparation of spiropyrrolooxindole derivatives, this method has short reaction times, high product yields, and the ability to separate catalyst and product using simple procedures. The spiropyrrolooxindoles can be found in many molecules of biological or pharmaceutical interest. Multicomponent reactions (MCRs) are a more interesting type of reaction due to mixing three or more reactants in one-pot and generating one product and economically useful and environmentally secure than to multi-step methods. Carrying out synthesis of organic compounds in water media is very interesting because of water is cheap solvent, more available with high amounts. [ABSTRACT FROM AUTHOR]

Imine-linked covalent organic frameworks (COFs) provide distinctive prospects for promoting photocatalytic H2O2 production, yet the intricate involvement of imine-derived linkages chemistry under light irradiation remains incompletely elucidated. Here, imine-linked COF-LZU1 demonstrates a visible light-driven H2O2 evolution rate of 387 μmol g-1 h-1, particularly, negligible dependence on the sacrificial agents. By virtue of electron paramagnetic spectroscopy and solid-state nuclear magnetic resonance, we experimentally tracked the structure evolution and identified its autooxidation to Wurster's salt mimics under the photocatalytic conditioning. This finding coincides with the radical anion ·O2- governed reaction pathway and is further rationalized with additional theoretical calculations. This study provides insights into both photophysical/photochemical aspects over the imine-linkage structure. [ABSTRACT FROM AUTHOR]

We investigate Ti(NEt2)4 supported on silica dehydroxylated at 700 °C as an easily accessible pre-catalyst for oxo/imido heterometathesis reactions. Being activated with TolNH2, the supported Ti amide (≡SiO)Ti(NEt2)3 (1) demonstrates catalytic activity in the imidation of ketones with N-sulfinylamines comparable with the most active previously described well-defined imido catalyst (≡SiO)Ti(＝NtBu)(Me2Pyr)(py)2 (2) (Me2Pyr = 2,5-dimethylpyrrolyl), which implies the in situ formation of surface imido species in this system. The materials obtained via treatment of 1 with anilines (TolNH2 (1a) and p-MeOC6H415NH2 (1b)) were studied with IR, EA and 1H, 13C, 15N and 2D solid-state NMR, although the proposed imido intermediate has not been detected, pointing towards tris-amides (≡SiO)Ti(NHC6H4X)3 (X = Me, OMe) being the major surface species in the isolated materials 1a and 1b. The system 1/TolNH2 was tested in a range of imidation reactions and demonstrated excellent performance for express high-yielding preparation of ketimines, formamidines, lactone imidates and sulfurdiimines, making it a convenient alternative to the well-defined supported Ti imido catalysts. [ABSTRACT FROM AUTHOR]

The Ti(OPr‐i)4‐mediated three–component condensation of enantiomeric Ellman's amides, dimethylphosphine oxide, and aliphatic, aromatic or heteroaromatic aldehydes proceeds in high yields and diastereoselectivities enabling the rapid, scalable and general asymmetric synthesis of (α‐amino)dimethylphosphine oxide derived compounds bearing alkyl, cycloalkyl or hetaryl group at the chiral carbon atom. Asymmetric synthesis of α‐amino‐α‐polyfluoroalkyl dimethylphosphine oxides was accomplished through diastereoselective addition of dimethylphosphine oxide to enantiomeric Ellman's aldimines, RFCH=NS(O)tert‐Bu (RF=CF3, CHF2, PhCF2). [ABSTRACT FROM AUTHOR]

The Schiff base condensation of 5-methyl-4-imidazole carboxaldehyde, 5Me4ImCHO, and the anion of an amino acid, H2N-CH(R)CO2− (R = -CH3, -CH(CH3)2 and -CH2CH(CH3)2), gives the aldimine tautomer, Im-CH=N-CH(R)CO2−, while that of 5-methylimidazole-4-methanamine, 5MeIm-4-CH2NH2, with a 2-oxocarboxylate anion, R-C(O)-CO2−, gives the isomeric ketimine tautomer, Im-CH2-N=C(R)CO2−. All are isolated as the neutral nickel(II) complexes, NiL2, and are characterized by single crystal structure determination, IR, and positive ion ESI MS. In the cases of the 4 substituted imidazoles, either 5MeIm-4-CHO or 5MeIm-4-CH2NH2, both the aldimine and ketimine complexes are isolated cleanly with no evidence of an equilibrium between the two tautomers under the experimental conditions. The aldimines are blue while the tautomeric ketimines are green. In contrast, for the 2-substituted imidazoles, with either Im-2-CHO or Im-2-CH2NH2, the isolated product from the Schiff base condensation is the ketimine, which in the solid is green, as observed for the 4-isomer. These results suggest that for the 2-substituted imidazoles, there is a facile equilibrium between the aldimine and ketimine tautomers, and that the ketimine form is the thermodynamically favored tautomer. The aldimine tautomers of the 4-substituted imidazoles have three stereogenic centers, the nickel (Δ or Ʌ) and the two alpha carbon atoms (R or S). The observed pair of enantiomers is the ɅRR/ΔSS enantiomeric pair, suggesting that this pair is lower in energy than the others and that this is in general the preferred chiral correlation in these complexes. [ABSTRACT FROM AUTHOR]

Fluorinated imines (Schiff bases) and fluorinated hydrazones are of particular interest in medicinal chemistry due to their potential usefulness in treating opportunistic strains of bacteria that are resistant to commonly used antibacterial agents. The present review paper is focused on these fluorinated molecules revealing strong, moderate or weak in vitro antibacterial activities, which have been reported in the scientific papers during the last fifteen years. Fluorinated building blocks and reaction conditions used for the synthesis of imines and hydrazones are mentioned. The structural modifications, which have an influence on the antibacterial activity in all the reported classes of fluorinated small molecules, are highlighted, focusing mainly on the importance of specific substitutions. Advanced research techniques and innovations for the synthesis, design and development of fluorinated imines and hydrazones are also summarized. [ABSTRACT FROM AUTHOR]

This article introduces a reductive coupling driven by visible-light, facilitating the synthesis of pyridine-substituted alcohols and amines through the reaction of aldehydes, ketones and imines with cyanopyridines. Hantzsch esters serve as reductants in this process, eliminating the need for transition-metals or photosensitizers. The method demonstrates extensive compatibility and finds utility in the late-stage functionalization of both natural and pharmaceutical products, offering a sustainable pathway for the diversification of chemical compounds. [ABSTRACT FROM AUTHOR]

This study explores a rational synthesis of a molybdenum‐promoted Ce−Si mixed oxide catalyst (MoO3/CeO2−SiO2) to regulate synergies between MoO3 and SiO2 dopant on CeO2, achieving high selectivity in solvent‐free catalytic oxidative coupling of amines to imines using molecular O2 as the oxidant. Comparative efficiency tests were conducted with bare CeO2, CeO2−SiO2, and MoO3/CeO2 catalysts. Characterization techniques, including XRD, Raman spectroscopy, N2‐adsorption‐desorption analysis, FTIR, NH3−TPD, TEM, and XPS, were employed to assess textural properties, acidic features, promoter and dopant dispersion in CeO2 lattice, and oxygen defects. Mo/Ce−Si catalyst exhibited superior acidic sites and a higher concentration of Ce3+ ions (Iu/ITotal), indicating increased oxygen vacancies. This catalyst demonstrated exceptional performance in the oxidative coupling of benzylamine, providing higher conversion and selectivity to the corresponding imine. Remarkably, the Mo/Ce−Si catalyst maintained consistent performance over five recycling runs. The catalyst also proved effective for the selective oxidative coupling of various amine substrates with diverse steric and electronic properties. Experimental results confirmed a plausible reaction mechanism within the concise catalyst design. [ABSTRACT FROM AUTHOR]

Modifying redox potential of substrates and intermediates to balance pairs of redox steps are important stages for multistep photosynthesis but faced marked challenges. Through co‐clathration of iridium photosensitizer and imine substrate within one packet of a metal‐organic capsule to shift the redox potentials of substrate, herein, we reported a multiphoton enzymatic strategy for the generation of heterocycles by intramolecular C−X hydrogen evolution cross‐couplings. The cage facilitated a pre‐equilibrium substrate‐involving clathrate that cathodic shifts the oxidation potential of the substrate‐dye‐host ternary complex and configuration inversion of substrate via spatial constraints in the confined space. The new two photon excitation strategy enabled the precise control of the multistep electron transfer between each pair (photosensitizer, substrate and the capsule), endowing the catalytic system proceeding smoothly with an enzymatic fashion. Three kinds of 2‐subsituted (−OH, −NH2, and −SH) imines and N‐aryl enamines all give the corresponding cyclization products efficiently under visible light irradiation, demonstrating the promising of the microenvironment driven thermodynamic activation in the host‐dye‐substrate ternary for synergistic combination of multistep photocatalytic transformations. [ABSTRACT FROM AUTHOR]

Development of new chiral ligands is essentially important in the field of asymmetric metal catalysis. Bispidines, steming from natural alkaloids, represent an intriguing yet underexplored class of chiral ligands. In this article, we developed a series of bispidine‐based chiral ligands with chirality locked in the side chain, and explore their properties by applying in the palladium‐catalyzed asymmetric addition of arylboric acids to cyclic N‐sulfonyl ketimines. A S,N‐bispidine ligand was found especially efficient, affording a series of chiral benzosultams with a quaternary chiral center in excellent yields with excellent ee values. Density functional theory (DFT) calculations and crystal structure of catalyst helped to propose a reasonable mechanism including a possible transition state model to explain the origin of stereoselectivity. [ABSTRACT FROM AUTHOR]

Lewis base dependent (3+3) and (4+2) annulations of β′‐acetoxy allenoates with N‐sulfonyl ketimines offer m‐teraryl and fused dihydropyridines with varying substituents depending on the tertiary amine as well as subtle changes in the reaction conditions. The triazabicyclodecene (TBD)‐catalyzed (3+3) annulation involves 1,2‐elimination followed by 6‐endo‐dig cyclization as key steps in delivering fused 1,4‐hydropyridines. The same reactants under DMAP catalysis offer m‐teraryl via Mannich coupling, rather than 1,2‐elimination followed by C−N bond cleavage/aromatization. Key intermediates have been identified by HRMS studies. [ABSTRACT FROM AUTHOR]

We report here a practical protocol for the asymmetric synthesis of amino acids (AAs) with a CF3‐containing 3,2'‐pyrrolidinyl spirooxindole skeleton with three defined carbon stereocenters via a sequential Michael/Mannich [3+2]‐cycloaddition reaction. The coupling of a robust and stereochemically stable chiral dehydroalanine Ni(II) complex with various N‐2,2,2‐trifluoroethylisatin ketimines in the presence of triethylamine afforded a library of single diastereomeric complexes with a 3,2'‐pyrrolidinyl spirooxindole moiety in 36–71% yields. In particular, the change of base to LiOH allowed to obtain predominantly the Michael addition product in 76% yield. Finally, the decomposition of the obtained Ni(II) complexes with 3 N HCl provided the target complex AA with a 3,2'‐pyrrolidinyl spirooxindole core and (2S,4R)‐2,4‐diamino‐5,5,5‐trifluoropentanoic acid – an (S)‐norvaline derivative, together with easy recovery of the chiral auxiliary ligand for the synthesis of the starting dehydroalanine complex. [ABSTRACT FROM AUTHOR]

In the context of a project aiming at the replacement of the 3‐substituted β‐lactam ring in classical β‐lactam antibiotics by an N(3)‐acyl‐1,3‐diazetidinone moiety, we have investigated the reaction of isocyanates with imines derived from allyl glycinate and differently substituted propionaldehydes. Imines of aromatic aldehydes with anilines have been reported to react with acyl isocyanates to give 1,3‐diazetidinones or 2,3‐dihydro‐4H‐1,3,5‐oxadiazin‐4‐ones, via [2+2] or [4+2] cycloaddition, respectively. However, neither of these products was formed with imines derived from allyl glycinate and 2‐(mono)methyl propionaldehydes. α,α‐Dimethylation of the imine enabled the [4+2] cycloaddition pathway, but the desired 1,3‐diazetidinone products were not observed. Surprisingly, the imines obtained from thioesters of 2,2‐dimethyl 3‐oxo propionic acid reacted with aryl isocyanates or with benzyl isocyanate to give 5,5‐dimethyl‐2,4‐dioxo‐6‐(aryl‐/alkylthio)tetrahydropyrimidines, via thiol displacement and re‐addition to a putative six‐membered iminium intermediate. These experimental results obtained for the reactions could be rationalized by DFT calculations. In addition, we have shown that N(3)‐acyl‐1,3‐diazetidinone and 2,3‐dihydro‐4H‐1,3,5‐oxadiazin‐4‐one products can be distinguished based on experimental IR data in combination with theoretical reference spectra employing the IR spectra alignment (IRSA) algorithm. This discrimination was not possible by means of 1H, 13C, or 15N NMR spectroscopy [ABSTRACT FROM AUTHOR]

The highly efficient reductive amination of aldehydes with ammonia (NH3) and hydrogen (H2) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN3-manganese(II) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH3 as a nitrogen source under H2 in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes. [ABSTRACT FROM AUTHOR]

The first catalytic enantioselective [5+1] cycloaddition reactions of C,N-cyclic azomethine imines with isocyanides are reported herein. The method displays a broad substrate scope and atom-economy. A series of chiral tetrahydroisoquinoline containing indole skeletons were obtained in up to 90% yield with 95% ee under mild reaction conditions. A possible catalytic model was also proposed. [ABSTRACT FROM AUTHOR]

Five new alkylaluminum complexes with different pyridinyl-substituted imines or cyclohexyl-substituted imines were synthesized and characterized successfully. The aluminum complex [FlCHNCH(CH3)Py]AlMe2(Py = 2-pyridyl) (1) was obtained by reacting 9-[2-pyridyl-CH(CH3)-N＝CH]Fl (Fl = fluorenyl) (L1) and equimolar AlMe3. The reactions of 9-(2-pyridyl-N＝CH)Fl (L2) and 9-[2-N(CH3)2-cyclohexyl-N＝CH]Fl (L3) with equimolar AlMe3 or AlEt3 afforded other alkylaluminum complexes [FlCHNPy]AlMe2(Py = 2-pyridyl) (2), [FlCHNPy]AlEt2 (Py = 2-pyridyl) (3), [FlCHNCyN(CH3)2]AlMe2 (Cy = 2-cyclohexyl) (4) and [FlCHNCyN(CH3)2]AlEt2 (Cy = 2-cyclohexyl) (5). All these complexes (1–5) were characterized using NMR spectroscopy, elemental analysis, and X-ray crystal structure analysis. The catalytic properties of these new alkylaluminum complexes for the hydrophosphonylation of aldimines were examined. Complex 5 showed the best catalytic performance under mild reaction conditions with a low catalyst loading (1 mol%), and 20 different substituents of aldimines were isolated with more than 90% yields. [ABSTRACT FROM AUTHOR]

Three Imines (H2L1-H2L3) were designed, synthesized, and examined the molecular docking with SARS-CoV-2 Mpro (PDB ID: 6LU7 & 7LKD). The molecular docking results reveals that the imines (H2L1-H2L3) with 6LU7 protein of SARS-CoV-2 virus exhibited the binding affinity (ΔG) of −6.0, −6.4, and −6.8 kcal/mol with good inhibition constant (Ki) of 4.113, 4.237, and 4.239 µM, respectively. The docking results of the imines (H2L1-H2L3) with 7LKD also resulted binding affinity (ΔG) of −7.3, −7.8, and −7.5 kcal/mol with good inhibition constant (Ki) of 4.459, 4.897, and 5.638 µM, respectively. The molecular docking analysis predicted that the imines (H2L1-H2L3) may be used as anti-SARS-CoV-2 virus. [ABSTRACT FROM AUTHOR]

This article discusses the development of new methods for synthesizing N-unsubstituted ketimines, which are valuable compounds used in the production of nitrogen-containing compounds. The researchers focused on using ketones as starting materials and scandium triflate as a catalyst. They optimized the reaction conditions and explored the effects of solvents and Lewis acid catalysts. The research provides more moderate and environmentally friendly methods for synthesizing N-unsubstituted ketimines, and also explores their application in one-pot reactions. The article also discusses the proposed reaction mechanism and hopes to inspire further development in related processes. [Extracted from the article]

Due to the oncoming climate changes, various environmental stresses (drought, salinity, heavy-metals, low or high temperatures, etc.) might dramatically affect crop yields and the quality of produced foods. Therefore, to meet the growing food demand of the human population, improvement of stress tolerance of the currently cultured crops is required. The knowledge of the molecular underlying mechanisms provides a versatile instrument to correct plant metabolism via chemical tools and to thereby increase their adaptive potential. This will preserve crop productivity and quality under abiotic stress conditions. Endogenously produced nitric oxide (NO) is one of the key signaling factors activating stress tolerance mechanisms in plants. Thus, the application of synthetic NO donors as stress-protective phytoeffectors might support maintaining plant growth and productivity under stressful conditions. Sydnone imines (sydnonimines) are a class of clinically established mesoionic heterocyclic NO donors which represent a promising candidate group for such phytoeffectors. Therefore, here, we provide an overview of the current progress in the application of sydnone imines as exogenous NO donors in plants, with a special emphasis on their potential as herbicides as well as herbicide antidotes, growth stimulants and stress protectors triggering plant tolerance mechanisms. We specifically address the structure–activity relationships in the context of the growth modulating activity of sydnone imines. Growth stimulating or antidote effects are typical for 4-α-hydroxybenzyl derivatives of sydnone imines containing an alkyl substituent in position N-3. The nature of the substituent of the N-6 atom has a significant influence on the activity profile and the intensity of the effect. Nevertheless, further investigations are necessary to establish reliable structure–activity relationships (SAR). Consequently, sydnone imines might be considered promising phytoeffector candidates, which are expected to exert either protective effects on plants growing under unfavorable conditions, or herbicidal ones, depending on the exact structure. [ABSTRACT FROM AUTHOR]

This article provides information on the synthesis and characterization of Schiff bases of sulfonamides and dihydropyridines using fluorophosphoric acid as a catalyst. The compounds synthesized have various applications, including the treatment of bacterial infections and conditions like hypertension and cardiac arrhythmias. The authors optimized the reaction conditions and found that the procedure could be applied to different substrates with good yields. The document includes detailed descriptions of the physical properties and spectroscopic data of each compound, as well as elemental analysis results. [Extracted from the article]

The wide applications of alpha‐boryl carbanions in selective coupling with organohalides, imines/carbonyls and conjugated unsaturated substrates has become an interesting tool for organic synthesis. Strategically, the inclusion of heteroatoms, such as Si, S, N, F, Cl, Br and I in the alpha position opens a new venue towards multifunctionalities in molecular design. Here, a conceptual and practical view on powerful carbanions, containing α‐silicoboron, α‐thioboron, α‐haloboron and α‐aminoboron is given, as well as a prespective on their efficient application for selective electrophilic trapping. [ABSTRACT FROM AUTHOR]

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Schiff base network1 (SNW1) is a recently synthesized covalent organic framework (COF) that has garnered significant interest in the field of materials science and chemistry. It is synthesized through the condensation reaction of melamine with terephthaldehyde and has abundance of imine functional groups present within its chemical structure. Due to its distinctive characteristics such as elevated specific surface area, exceptional thermal and chemical durability, simple synthesis process, and notable electrochemical conductivity, numerous investigations have been conducted on this COF across diverse analytical chemistry domains. Our research group also explored the applications of this COF and its composites in different fields like microextraction methods, adsorptive removal of environmental contaminants, and electrochemical sensing of heavy metals. In this respect, we decided to introduce SNW1 COF in this short review and have a detailed discussion on its chemistry, and its scrutinized applications in analytical chemistry. Additionally, the literature that has been analyzed yielded pivotal insights, and a set of suggestions have been formulated for subsequent scholarly pursuits. [ABSTRACT FROM AUTHOR]

Based on the density functional theory, the stereoselectivity of the asymmetric synthesis of tetrahydroisoquinolinopyrazole derivatives by the cycloaddition reaction of C, N‐cyclic azomethine imines with allyl alkyl ketones which was catalyzed using a chiral primary amine is studied theoretically. The results demonstrate that the four chiral transition states (TS‐1R2R, TS‐1R2S, TS‐1S2R and TS‐1S2S) are formed by the reaction of dienamine intermediate with C, N‐cyclic azomethine imine, and the reaction barrier of TS‐1R2S is in the lowest level (ΔG=6.98 kcal/mol). The consequence reveal that the 1R2S configuration product is formed by TS‐1R2S transition state. Non‐covalent interaction and electron density topology analysis show that the stereoselectivity of the chiral product is determined through van der Waals forces and hydrogen bond interaction of the transition state molecules. [ABSTRACT FROM AUTHOR]

The art of tuning functional polymeric materials through the covalent incorporation of organocatalysts lies at the core of creating asymmetric immobilized chiral catalysts that mimic the enzymatic action. Herein, we explore diverse synthetic techniques to immobilize l‐proline‐derived N‐carbonyl amides on functional polymeric matrices, transforming them into chiral Lewis bases for facilitating the asymmetric reduction of ketimines with HSiCl3. A comprehensive examination of the design factors, encompassing linker selection, anions, and polymeric support characteristics, enables precise adjustment of steric and electronic features in these immobilized catalysts. This approach establishes structure‐performance relationships, ultimately enabling the development of an engineered immobilized organocatalytic system that meets the desired criteria for activity, stability, and selectivity. [ABSTRACT FROM AUTHOR]

Dicyanoalkenes are versatile reagents in organic synthesis and they have been extensively used in a wide variety of organic transformations. However, their reactivity towards fluorinated imines remained almost unnoticed. The divergent reactivity of fluorinated conjugated sulfinyl imines with dicyanoalkenes is described herein. On the one hand, when tert‐butyl sulfinyl imines were employed, a cycloaromatization cascade process took place preferentially, rendering valuable trifluoromethyl arenes. On the other hand, the reaction with p‐tolyl sulfinyl imines mainly led to a complex tetracyclic skeleton, involving an azetidinimine rearrangement of a reaction intermediate. Finally, when 1‐indanone‐derived dicyanoalkenes were employed, the aromatization process was interrupted, rendering a new family of diene derivatives. Theoretical calculations were performed in order to shed light on the mechanistic outcome of this transformation. [ABSTRACT FROM AUTHOR]

The stereoselective reaction of α‐amido‐substituted malonic acid half oxyesters (α‐amido‐MAHOs) with isatins was developed. A cinchona alkaloid thiourea catalyst gave products bearing a tetrasubstituted stereogenic centre in high yields with high diastereo‐ and enantioselectivities (75–99% yield, 83:17–97:3 dr, 92:8–99:1 er). The obtained products can be converted into some chiral compounds without loss of enantiopurity. Density functional theory (DFT) calculations were conducted to clarify the origin of stereoselectivities, and suggested that the first stereogenic centre is set in the decarboxylation, the second in the protonation. [ABSTRACT FROM AUTHOR]

A regio‐ and diastereoselective conjugate addition reaction of Grignard reagents to fluoroalkyl α,β‐unsaturated N‐tert‐butanesulfinyl ketimines was disclosed. A range of different fluoroalkyls and Grignard reagents were well tolerated, giving up to 99% diastereomeric and regioisomeric ratios. This reaction provided a straightforward method for the synthesis of a variety of enantiomerically enriched α‐fluorinated enamines and derivatives which are difficult to achieve with other methods. [ABSTRACT FROM AUTHOR]

Organometallic drug development is still in its early stage, but recent studies show that organometallics having iron as the central atom have the possibility of becoming good drug candidates because iron is an important micro-nutrient, and it is compatible with many biological systems, including the human body. Being an eco-friendly Lewis acid, iron can accept the lone pair of electrons from imino(sp2)-nitrogen, and the resultant iron–imine complexes with iron as a central atom have the possibility of interacting with several proteins and enzymes in humans. Iron–imine complexes have demonstrated significant potential with anticancer, bactericidal, fungicidal, and other medicinal activities in recent years. This article systematically discusses major synthetic methods and pharmacological potentials of iron–imine complexes having in vitro activity to significant clinical performance from 2016 to date. In a nutshell, this manuscript offers a simplistic view of iron complexes in medicinal inorganic chemistry: for instance, iron is presented as an "eco-friendly non-toxic" metal (as opposed to platinum) that will lead to non-toxic pharmaceuticals. The abundant literature on iron chelators shows that many iron complexes, particularly if redox-active in cells, can be quite cytotoxic, which can be beneficial for future targeted therapies. While we made every effort to include all the related papers, any omission is purely unintentional. [ABSTRACT FROM AUTHOR]

We present a green and efficient protocol for the synthesis of various imines including challenging α,β-unsaturated imines directly from alcohols and amines via a tandem oxidative cross-coupling strategy. The reaction is catalyzed by ruthenium nanoclusters supported on a cubic ordered mesoporous carbon (CMK-8) under ambient air pressure (622 Torr) and mild aqueous conditions without requiring a base or other additives. The catalyst shows excellent activity and selectivity for a broad range of alcohols and amines, giving the desired imines in excellent yield and high purity. The catalyst was characterized by various analytical techniques such as N2 sorption analysis, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), high-resolution transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM, and the corresponding elemental mapping. The results revealed that the catalyst has a large surface area, uniform pore size distribution with ordered cubic arrangement, and active Ru species with very small sizes (mostly less than 1 nm), which most likely accounts for its exceptional catalytic performance. Hot filtration and recycling tests demonstrated that the catalyst operated heterogeneously and remained active for at least three cycles. [ABSTRACT FROM AUTHOR]

The first enantioselective reduction of 2‐substituted cyclic imines to the corresponding amines (pyrrolidines, piperidines, and azepines) by imine reductases (IREDs) in non‐conventional solvents is reported. The best results were obtained in a glycerol/phosphate buffer 1 : 1 mixture, in which heterocyclic amines were produced with full conversions (>99 %), moderate to good yields (22–84 %) and excellent S‐enantioselectivities (up to >99 % ee). Remarkably, the process can be performed at a 100 mM substrate loading, which, for the model compound, means a concentration of 14.5 g L−1. A fed‐batch protocol was also developed for a convenient scale‐up transformation, and one millimole of substrate 1 a was readily converted into 120 mg of enantiopure amine (S)‐2 a with a remarkable 80 % overall yield. This aspect strongly contributes to making the process potentially attractive for large‐scale applications in terms of economic and environmental sustainability for a good number of substrates used to produce enantiopure cyclic amines of high pharmaceutical interest. [ABSTRACT FROM AUTHOR]

Reaction of gossypol with thiohydrazides of oxamic acids produces the corresponding hydrazones existing in the imine-imine form. [ABSTRACT FROM AUTHOR]

The synthesis and functionalization of privileged nitrogen heterocycles has emerged as a central topic in drug discovery and material science. In this context, the tandem C–H functionalization and intramolecular annulation has received prodigious attention, as it is able to expedite the construction of heteroaromatic frameworks beyond conventional C–H functionalization. In general, significant effort has been made to develop the [3 + 2] dipolar cycloaddition of azomethine imines with π‐unsaturated compounds. Moreover, the [3 + 3], [4 + 3], [3 + 2 + 2], and [5 + 3] cycloaddition reactions of azomethine imines with various dipolarophiles have been demonstrated. To date, however, the combination of catalytic C–H functionalization and intramolecular cyclization using azomethine imines as both directing groups and dipolar units has been less explored. This review focuses on recent progress toward the catalytic tandem C–H functionalization and dipolar cycloaddition of azomethines imines with a range of coupling partners. [ABSTRACT FROM AUTHOR]

2 + 2 Photocycloadditions are idealized, convergent construction approaches of 4-membered heterocyclic rings, including azetidines. However, methods of direct excitation are limited by the unfavorable photophysical properties of imines and electronically unbiased alkenes. Here, we report copper-catalyzed photocycloadditions of non-conjugated imines and alkenes to produce a variety of substituted azetidines. Design principles allow this base metal-catalyzed method to achieve 2 + 2 imine-olefin photocycloaddition via selective alkene activation through a coordination-MLCT pathway supported by combined experimental and computational mechanistic studies.

Growing interest in sustainable sources of chemicals and energy from renewable and reliable sources has stimulated the design and synthesis of renewable Schiff-base (iminium) ionic liquids (ILs) to replace fossil-derived ILs. In this study, we report on the synthesis of three unique iminium-acetate ILs from lignin-derived aldehyde for a sustainable “future” lignocellulosic biorefinery. The synthesized ILs contained only imines or imines along with amines in their structure; the ILs with only imines group exhibited better pretreatment efficacy, achieving >89% sugar release. Various analytical and computational tools were employed to understand the pretreatment efficacy of these ILs. This is the first study to demonstrate the ease of synthesis of these renewable ILs, and therefore, opens the door for a new class of “Schiff-base ILs” for further investigation that could also be designed to be task specific.

Bismuth(III) triflate-catalyzed [4+2]-annulation of cyclic N-sulfonyl ketimines (derived from saccharin) and alkynyl alcohols (4-pentyn-1-ols and 5-hexyn-1-ols) has been reported. This cascade annulation provides a diverse array of polycyclic spiro-and-fused N,O-ketals with excellent substrate scope, good isolated yields, and diastereoselectivities under mild reaction conditions. [ABSTRACT FROM AUTHOR]

The annulation of arynes with dibenzo[b,f][1,4]oxazepines (N‐aryl cyclic imines) in the presence of CO2 has been studied in comparison with 3,4‐dihydroisoquinolines (N‐alkyl cyclic imines). For the reaction with dibenzo[b,f][1,4]oxazepines, [2+2] annulation takes place specifically with arynes, with CO2 acting only as the protecting gas. 3,4‐dihydroisoquinolines, however, exclusively underwent [2+2+2] annulation with arynes and CO2, with CO2 as a reactant. Our findings offer insights into imine‐aryne annulation under CO2 and suggest that steric and nucleophilic factors control the annuloselectivity. Reactivity analysis revealed that electron‐rich and less steric N‐alkyl cyclic imines and electron‐deficient benzynes favor the [2+2+2] annulation, while electron‐deficient and bulky N‐aryl cyclic imines prefer the [2+2] annulation. In the [2+2] annulation, the Hammett analyses reveal that both the nucleophilic attack of imines to benzynes (the first step, negative ρ) and the attack of phenyl anions on the iminium species (the second step, positive ρ) affect the reaction rate. [ABSTRACT FROM AUTHOR]

Azomethine imines, as a prominent class of 1,3‐dipolar species, hold great significance and potential in organic and medicinal chemistry. However, the reported synthesis of centrally chiral azomethine imines relies on kinetic resolution, and the construction of axially chiral azomethine imines remains unexplored. Herein, we present the synthesis of axially chiral azomethine imines through copper‐ or chiral phosphoric acid catalyzed ring‐closure reactions of N′‐(2‐alkynylbenzylidene)hydrazides, showcasing high efficiency, mild conditions, broad substrate scope, and excellent enantioselectivity. Furthermore, the biological evaluation revealed that the synthesized axially chiral azomethine imines effectively protect dorsal root ganglia (DRG) neurons by inhibiting apoptosis induced by oxaliplatin, offering a promising therapeutic approach for chemotherapy‐induced peripheral neuropathy (CIPN). Remarkably, the (S)‐ and (R)‐atropisomers displayed distinct neuroprotective activities, underscoring the significance of axial stereochemistry. [ABSTRACT FROM AUTHOR]

Ternary NiTiFe-LDH with an ultrathin nanosheet morphology was successfully fabricated via a facile co-precipitation method, followed by refluxing, and was used as a catalyst for oxidative coupling of amines to produce imines under visible light. The obvious superior activity observed in NiTiFe-LDH ultrathin nanosheets compared with binary NiTi-LDH and bulk NiTiFe-LDH can be ascribed to an enhanced light absorption capability caused by the introduction of Fe3+ ions as well as the ultrathin nanosheets which can minimize the recombination of the photogenerated charge carriers and provide more catalytically active sites for the reaction. As a result, more catalytically active O2˙− radicals are generated over NiTiFe-LDH ultrathin nanosheets, which leads to their superior activity. This study not only shows the possibility of using LDHs in photocatalytic organic transformations but also demonstrates an effective strategy to promote the activity of LDH-based photocatalysts via simultaneous composition and morphology modulation of LDHs. [ABSTRACT FROM AUTHOR]

An in situ generated photoactive copper(I)‐complex‐catalyzed aziridination reaction of cyclic N‐sulfonyl imines with α‐aryl‐substituted vinyl azides irradiated by blue‐LEDs light is reported for the first time. This novel SET process represents a mild, sustainable, and pragmatic method for accessing synthetically resourceful sulfamidate‐fused aziridines in acceptable chemical yields with excellent diastereoselectivities. Delightedly, pharmacologically attractive benzo[f][1,2,3]oxathiazepine dioxides and fused isoxazoline frameworks were achieved through our newly developed metal‐free based ring‐expansion techniques, highlighting the synthetic value of accessed aziridines. Finally, the possible mechanism for [2+1] aza‐cyclization was presented based on the conduction of a series of control experiments. [ABSTRACT FROM AUTHOR]

A new concept for analyzing primary amines using a novel 19F NMR reporter bearing two different fluorine‐containing moieties is described herein. The 19F NMR reporter, 4‐fluoro‐2‐(trifluoroacetyl)‐aminobenzaldehyde, was readily synthesized from a commercially available fluorine‐containing anthranilic acid derivative in two steps. After the imine formation of the NMR reporter with amines, 2D plots of two 19F shift‐related values were obtained. Amines with various types and sizes could be discriminated on the plot. [ABSTRACT FROM AUTHOR]

This account is a collection of vignettes describing new reactions discovered in the author's group revolving around the chemistry of oximes. They range from ionic transformations, including reduction to unsubstituted imines and the formation of α-electrophiles, to the generation and capture of iminyl radicals, to a general synthesis of alkynes. The mechanistic reasonings and occasional serendipitous observations underlying these discoveries are discussed briefly. [ABSTRACT FROM AUTHOR]

A new strategy to access α‐functionalized alicyclic amines via their corresponding imine‐BF3 complexes is reported. Isolable imine‐BF3 complexes, readily prepared via dehydrohalogenation of N‐bromoamines in a base‐promoted/18‐crown‐6 catalyzed process followed by addition of boron trifluoride etherate, undergo reactions with a wide range of organometallic nucleophiles to afford α‐functionalized azacycles. Organozinc and organomagnesium nucleophiles add at ambient temperatures, obviating the need for cryogenic conditions. In situ preparation of imine‐BF3 complexes provides access to α‐functionalized morpholines and piperazines directly from their parent amines in a single operation. α‐Functionalized morpholines can be elaborated further, for instance by installing a second substituent in the α′‐position. [ABSTRACT FROM AUTHOR]