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The synthesis and characterization of two distinct novel series of compounds, [II]n and [V]n, containing 1,3,4-thiadiazole units, were studied in this work. The central core of the first series is phenyl, whereas the central core of the second series is OCH2CH2O. FTIR,1HNMR,13CNMR, and mass spectroscopy are used to characterize the materials used in this investigation. Liquid crystalline properties were confirmed by the use of differential scanning calorimeter (DSC) and hot-stage polarizing optical microscopy (POM). While other compounds showed no liquid crystalline behavior, the compounds [II]3–[II]6, [V]1and [V]n showed enantiotropic nematic and smectic phases. [ABSTRACT FROM AUTHOR]

Imine-linked covalent organic frameworks (COFs) are highly ordered polymer networks that are more chemically stable compared to their boron-linked counterparts making them more attractive for a variety of applications, including as energy storage devices, proton-conductive membranes, and catalytic supports. Furthermore, these imines linked COFs may be synthesized using a diverse spectrum of monomers, providing tremendous design freedom and versatility. We report a general method for synthesizing Imine linked COFs based on the Schiff-base condensation reaction of anilines. The synthesis of 4,4′,4′′-(benzene-1,3,5-triyltris(ethyne-2,1-diyl) trianiline, 4,4′-dicarbaldehyde, 4,4′-(ethyne-1,2-diyl) dibenzaldehyde (BPDA), and terephthalaldehyde (PDA) monomers produced by multistep coupling processes. [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]

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 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]

Secondary phosphine oxides R2P(O)H are a relatively stable tautomeric form of secondary phosphinous acids R2P–OH that with imine/iminium species, or their donors, form compounds with a P(O)–Csp3–N linkage (the phospha-Mannich reaction). These can be referred to as (α-aminoalkyl)phosphine oxides, (α-phosphinoylalkyl)amines, or P(O),N-acetals. Compared to P–Csp3–N linkages of P,N-acetals, products of phospha-Mannich reactions involving secondary phosphines R2PH, the P(O)–Csp3–N linkage is significantly more stable that allows for many examples of α-functionalized P(O),N-acetals and α-phosphinoylated N-heterocycles, whereas such examples for P,N-acetals are rare. Trivalent derivatives of phosphinous acids such as halides R2P–Hal, esters R2P–OR' (phosphinites), amides R2P–NR'2 (aminophosphines), and phosphides R2P–PR'2 (biphosphines) also participate in Mannich-type reactions with mechanisms depending on the reactants. The phosphinous halides and esters react with (α-alkoxyalkyl)amines (N,O-acetals) and (α-haloalkyl)amines (N,Hal-acetals), respectively, via Arbuzov-type intermediates that are rearranged into P(O),N-acetals and alkyl halides (Arbuzov rearrangement). Furthermore, unlike phospha-Mannich reactions involving phosphines, secondary phosphine oxides and P(O),N-acetals are less sensitive to oxidation, and imines/iminium species can be generated not only under conventional Mannich conditions, i.e., from N,E-acetals (E = OH, O, N, halogen, etc.), but also, for example, by oxidation of α-C-atom of amines, or by oxidation of alcohols to aldehydes that than form imines/iminium species with amines. [ABSTRACT FROM AUTHOR]

A series of structurally diverse spiro 1,3-oxazines were conveniently prepared from three-component reaction of conjugated imines, dialkyl acetylenedicarboxylates (DAAD), and N,N'-disubstituted parabanic acids in dry dichloromethane without catalyst. Initially, various conjugated imines were synthesized from reaction of aniline derivatives with cinnamaldehyde. Subsequently, reaction of conjugated imines with DAAD and N,N'-substituted parabanic acids led to mixture of the corresponding spirocyclic 1,3-oxazines in high yields. The obtained diastereoisomers of the spirocyclic 1,3-oxazines were isolated and characterized by FT-IR, 1H, 13C NMR spectral data, elemental analyses and mass spectrometry. [ABSTRACT FROM AUTHOR]

The coupling reactions of amines into imines oxidized by persulfate with the assistance of ultrasound were carried out. The reaction conditions were optimized and the effect of ultrasonic was also investigated. The results indicated that Na2S2O8 in combination with ultrasound possessed excellent oxidative performance, which made this transformation smoothly proceed under the conditions of solvent-/catalyst- free, and low reaction temperature, giving excellent yields of imines in short reaction time. Our procedure had high reaction tolerance to various primary benzylic amines, demonstrating good universality. Furthermore, a tentative reaction mechanism and pathway were proposed. [ABSTRACT FROM AUTHOR]

Three new Schiff bases (1a–3a) were synthesized as the starting compounds with the reaction of 5-(2-nitrophenyl)-2-furfural and 2-hydroxy-5-X aniline (X: H, Cl, Me, respectively). Afterwards, the asymmetric diimine ligands (1b–3b) were obtained by a two-step method as follows: nitro group of the starting Schiff bases was reduced into their amino derivative in solution and were reacted with 2-hydroxy-1-naphthaldehyde. Ni(II) complexes of the diimines (1c–3c) were then synthesized. The starting Schiff bases, asymmetric diimines and their complexes were characterized by elemental analyses, IR, LC-MS, TGA, UV-vis, 1H and 13C-NMR, conductivity and magnetic measurements. Square planar geometry was proposed for the complexes. The protonation constants of all the Schiff bases and the stability constants of the complexes were determined potentiometrically in 50% ethanol-water solution (1:1, v/v) at 25 °C and 0.5 M KCl ionic strength. [ABSTRACT FROM AUTHOR]

Recent achievements in asymmetric synthesis of α-polyfluoroalkylated aminophosphonic acid derivatives from C-phosphorylated imines are summarized. The synthetic potential of fluoroalkylated iminophosphonates was revealed by their easy diastereoselective functionalization (hydrogenation, proline-catalyzed Mannich reaction with acetone, cycloaddition with diazomethane) to afford optically active compounds bearing biorelevant α-polyfluoroalkylated α-aminophosphonic fragment. [ABSTRACT FROM AUTHOR]

Phosphorus-based Mannich-type reactions (phospha-Mannich reactions) of primary or secondary phosphines with carbonyl compounds and amines (R2NH, RNH2, and NH3) provide a powerful synthetic tool in the worldwide search for future ligands. The variety of amines and phosphines available allows for designing and fine-tuning water-soluble, chiral, macrocyclic, pincer, tripodal, photoactive, and etc., phosphine ligands with P–C–N linkage(s) (P,N-acetals). Aminized supports and amine-terminated dendrimers can easily be phosphine-functionalized by phospha-Mannich reactions, and used in reusable heterogeneous catalysts. If CH2O is used as a C-component, its stable adducts with phosphines, that is, RP(CH2OH)2 and R2PCH2OH, are often used in syntheses of P,N-acetals as they are less toxic and non-pyrophoric analogs of the phosphines, whereas other carbonyl compounds are usually converted into imines or iminium salts. In phospha-Mannich reactions, tertiary phosphines form a P+–C–N linkage (P+,N-acetals) that can easily be broken by bases, realizing imine, or iminium cations, and are used as imine/iminium donors in organic syntheses. [ABSTRACT FROM AUTHOR]

The easiest route to form compounds with P–Csp3–N linkage(s) is phosphorus-based Mannich-type reactions (phospha-Mannich reactions) between phosphines (R3P, R2PH, RPH2, PH3), carbonyl compounds (mainly CH2O) and amines (R2NH, RNH2, NH3). Because of toxicity and inflammability, applications of PH3 and its liquid analog (Me3Si)3P in such reactions are rare. Stable, less toxic, and non-pyrophoric adducts of PH3 with CH2O, i.e., tris(hydroxymethyl)phosphine (HOCH2)3P and tetrakis(hydroxymethyl)phosphonium (HOCH2)4P+ salts, are often used as both P- and C-sources in phospha-Mannich reactions, providing many acyclic and cyclic P,N-ligands, among which 1,3,5-triaza-7-phosphaadamantane (PTA) is most known. Phospha-Mannich reactions of (HOCH2)4P+ salts with urea form condensation products that are used to impart fire retardance to cotton materials, the most important and oldest area of application of the salts. The use of (HOCH2)3P and (HOCH2)4P+ salts as cross-linking agents in protein-based hydrogel manufacturing, enzyme immobilization on NH2-containing supports, and leather tanning, is also based on phospha-Mannich reactions and ability to form P–CH2–N linkages with amino acids residues. Mechanistic aspects of phospha-Mannich reactions are discussed. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the occurrence of the most representative cyclic imines (CIs) gymnodimine (GYM), pinnatoxin G (PnTX-G), and 13-desmethyl SPX C (SPX1) in Mediterranean mussels (Mytilus galloprovincialis Lamarck, 1819) (n = 416), European oysters (Ostrea edulis Linnaeus, 1758) (n = 104), Queen scallops (Aequipecten opercularis Linnaeus, 1758) (n = 52) and edible ascidians of the Microcosmus spp. (n = 104) originating from nine harvesting and breeding areas in the northern part of the Adriatic Sea using ultra-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). All CI concentrations were far below the guidance level of 400 μg SPXs/kg proposed by the EU Reference Laboratory for Marine Toxins. In contrast to Queen scallops and ascidians, in Mediterranean mussels and European oysters CIs were found throughout the year. Our data reveal the differences between species predisposed for CIs accumulation, as well as seasonal and locational variations in CIs occurrence. [ABSTRACT FROM AUTHOR]

An innovative and simple approach for the reduction of aldimines to the corresponding secondary amines was described using biosynthesized nickel oxide nanoparticles as heterogeneous catalyst and ammonium formate as the hydrogen donor. This catalytic transfer hydrogenation method was highly efficient and helps to synthesize amines with remarkable yields and without any coarse environment. [ABSTRACT FROM AUTHOR]

Peptic ulcer is a common disorder of the gastrointestinal system affecting people of all ages worldwide. Ethanol is one of the most common causative agents for peptic ulcer. The aim of this study was to evaluate the protective effect of two newly synthesized indole imines (389 and 393) against ethanol-induced gastric ulcer in rats. Animals were orally administered different treatments: group I–II (vehicle & ulcer controls, respectively); 0.5% aqueous CMC solution, group III (standard control; omeprazole; 20 mg/kg bw); groups IV–VI, test compound 389 (20, 40 and 60 mg/kg bw) and groups VII–IX, test compound 393 (20, 40 and 60 mg/kg bw). Various parameters including pH, gastric contents, ulcer index and percentage protection were determined and histopathological study of gastric mucosa was performed to evaluate the protective effect of the test compounds. Oral administration of the test compounds, i.e. 389 and 393 (20, 40 and 60 mg/kg bw), significantly (p < 0.05) reduced the ulcer index in a dose-dependant manner as compared to the ethanol-induced ulcer control group. The gastroprotective potential of the studied test compounds was supported by the histological examination of the gastric mucosa showing a decreased inflammatory response with less oedema and leucocyte infiltration. The study concluded that the synthesized test compounds possess antiulcerogenic potential possibly due to their anti-inflammatory effects. [ABSTRACT FROM AUTHOR]

This paper provides the fifth manifestation of a new tradition by which the editors of Comments on Inorganic Chemistry wish to lead by example, whereby we start publishing original research content that, nonetheless, preserves the Journal's identity as a niche for critical discussion of contemporary literature in inorganic chemistry (For the previous manifestations, see: Comments Inorg. Chem. 2018, 38, 1–35; 2019, 39, 1–26; 2019, 39, 188–215; 2020, 40, 1–24.) Herein, synthetic details, solid-state structures, and photophysical properties of a group of silver(I) and copper(I) complexes are described. Two silver-based coordination polymers have been obtained: {[3,5-(CF3)2Pz]2(bpp)Ag2}∞ (1) and {[3,5-(CF3)2Pz][5-(C6F5)Ttz](bpp)Ag}∞ (2) – constructed from bent 1,3-bis(4-pyridyl)propane (bpp), 3,5-bis(trifluoromethyl)pyrazole ([3,5-(CF3)2Pz]H) and 5-pentafluorophenyl-tetrazole ([5-(C6F5)Ttz]H) in order to inspect the influence of mixed ligands on the resulting silver-based coordination complexes. The structure of 1 shows a distorted trigonal planar geometry with both the bpp and [3,5-(CF3)2Pz] ligands binding to the silver atom. The silver in 2 shows an uncommon interaction with the three different ligands. Also, two different geometries including distorted tetrahedral and distorted trigonal were presented for two different silver atoms. An interesting result was obtained for the Cu(I) coordination polymer {[Cu(bpp)2][BF4]}∞ (3) which was successfully synthesized in a solventless reaction but not a solvent-mediated reaction, hence manifesting a "green" chemistry route. The structure of 3 shows an ideal tetrahedral geometry similar to that for the silver analogue, {[Ag(bpp)2][BF4]}∞ (3a), published previously, whereas herein we obtained the same product with the same crystal structure via a more facile conventional synthetic route. All four complexes show bpp ligand-centered green emissions at ambient and cryogenic temperatures. Finally, a commentary is added to contrast the solventless vs solvent-mediated reactions in both this investigation and a precedent thereof by the same corresponding author's group (Inorg. Chem. 2018, 57, 9962–9976), whereby reactions proceeded successfully only via the solventless route through mechanical grinding herein and spontaneous sublimation by vapor diffusion from the solid-state of one reactant to another yet nonvolatile reactant in the literature precedent, respectively. [ABSTRACT FROM AUTHOR]

In this study, an imine compound 2-((phenylimino)methyl)phenol was synthesized by the reaction of salicylaldehyde and aniline for in situ monitoring of reduction with sodium borohydride. The reduction of C = N double bond to C–N in solution was continuously monitored by infrared spectroscopy using the background defining method in liquid cell at ambient temperature. The structures of the purified 2-((phenylimino)methyl)phenol compound and the resulting 2-((phenylamino)methyl)phenol compound were elucidated by Infrared Spectroscopy, H1 and C13 Nuclear Magnetic Resonance Spectroscopy. [ABSTRACT FROM AUTHOR]

Friedelan-3-one (1) and friedelane-3,16-dione (2) isolated from leaves and branches of Maytenus robusta Reissek were subjected to structural modifications via nucleophilic addition to the carbonyl group and Baeyer-Villiger oxidation in order to synthesize potential cytotoxic compounds. The oximes friedelane-3-hydroxyimino (3) and 3-hydroxyiminofriedelan-16-one (4) together with the lactones friedelane-3,4-lactone (5) and 3,4-lactonefriedelan-16-one (6) were characterized by IR and NMR spectroscopic analyses. Compounds 4 and 6 are reported for the first time. Cytotoxic screening via MTT assay in human leukemia cell lines (THP-1 and K562) demonstrated no significant improvement of compounds 3-6 when compared to the starting materials. Only compounds 3 and 5 demonstrated an improvement against K562 cells. However, the same assay on ovarian and breast cancer cell lines (TOV-21G and MDA-MB-231) showed a reduction in the IC50 for compounds 4-6, indicating that ring A modifications may enhance the biological potential. [ABSTRACT FROM AUTHOR]

A series of novel [3]ferrocenophane-derived N/B frustrated Lewis pairs (FLPs) were synthesized and successfully applied to the catalytic hydrogenation of imines in 71-93% yields. This approach could be easily conducted on gram scale and provided versatile synthetic route for the key intermediate of sertraline hydrochloride without heavy metal residues. [ABSTRACT FROM AUTHOR]

Heterocyclic imines provide biaryl products by a two-step transformation. The first transformation involves a Diels-Alder reaction with a multiply protonated imine to give a tetrahydroquinoline product, whereas the second step involves oxidation with elemental sulfur at 260 °C. [ABSTRACT FROM AUTHOR]

The kinetic study on the hydrolysis of Schiff bases (SBs) 1a-c and 2a-c induced by UV-vis was undertaken as a complementary study of the stability in solution and in bulk of the SBs. Solutions in chloroform were exposed to UV-vis and acquisition data occurred for 1a-c and for 2a-c in 21°C, 30 °C, 35°C and 40°C. Kinetic profile for 1a-c and 2a-c displayed the similar photochemical behaviour in that four temperature values. At 21°C, two kinetic regimes were observed where the decomposition of SBs is faster at the initial stage, with no linear plot of absorbance vs time, and after the kinetic profile obeyed a linear behaviour. A mathematical treatment of the experimental data was applied, which allowed associating the initial stage data with a second-order reaction, and the final stage of the hydrolysis with a first-order reaction. The mechanism of photochemical hydrolysis of SBs 1a and 2a was addressed. It was composed of three parts, the excitation, then the isomerisation and activation processes of tetrahedral intermediate and, the last process, a collapse of the intermediate to the yielded products of the hydrolysis aldehydes and amines which were detected by their UV-vis spectrum. [ABSTRACT FROM AUTHOR]

A series of new calamitic liquid crystals, 4-{[(pyridin-4-yl)methylidene]amino}phenyl 4-alkoxybenzoates comprising a heterocyclic (pyridine) and two phenyl rings core system, terminal alkoxy chain, imine and ester linkers were synthesised and characterised. This series consists of nine members wherein the members differ by the length of alkoxy chain (CnH2n+1O-, where n = 2, 4, 6, 8, 10, 12, 14, 16, 18). Spectral analysis results were in accordance with the expected structure. Their thermotropic behaviours were studied by using differential scanning calorimetry, optical polarising microscopy and powder X-ray diffraction techniques. A single mesophase (nematic) was observed for the first three members of the series (n = 2, 4 and 6). As the alkoxy chain increased to n = 8 and n = 10, the nematic phase appeared together with an additional smectic A (SmA) phase. When moving from n = 12 until the highest members (n = 18), the nematic phase disappeared and these compounds only exhibited a single mesophase (SmA). [ABSTRACT FROM AUTHOR]

Optically pure hetero-organic organocatalysts, bearing a hydroxy moiety, a stereogenic sulfinyl group and a chiral amine moiety, have revealed high catalytic activity in the asymmetric reduction of various N-aryl ketimines leading to the corresponding chiral amines. Desired products were formed in high chemical yields (up to 95%) and with ee’s up to 97%. The influence of particular stereogenic centres on the stereochemical outcome of the reduction reaction is discussed. [ABSTRACT FROM AUTHOR]

A simple, facile, and high yielding stereoselective approach for the integration of α-methylene-pyrazole-carboxylates at the β-lactam nucleus is described. These monocyclic β-lactams have been synthesized by treatment of 2-phenoxy/benzylthio/phenylthio ethanoic acids or acetoxyacetyl chloride/phthalimidoacetyl chloride 5a-e with novel α-methylene-pyrazole-carboxylate imines 4a-c using Et3N and POCl3 in refluxing toluene. All of the newly synthesized α-methylene-pyrazole carboxylate imines 4a-c and their β-lactam derivatives 6a-h have been fully characterized by spectroscopic techniques such as FTIR, NMR (1H, 13C, and 13C DEPT-135), 2D-NMR (COSY and HSQC), and elemental analyses (CHN). The cycloaddition reaction was found to be highly stereoselective leading to the exclusive formation of trans-β-lactams 6a-h and trans configuration was assigned with respect to coupling constant values of C3-H and C4-H. The novel β-lactams 6a-h bearing α-methylene-pyrazole-carboxylate ring system will serve as useful synthons for highly functionalized acids, acetohydrazides/pyrazolones, alcohols, pyrazole carboxamides, peptides, and promising biologically active agents. [ABSTRACT FROM AUTHOR]

A series of structurally diverse 4-trifluoromethyl β-sultams was conveniently synthesized via the sulfa-Staudinger cycloadditions of 2,2,2-trifluoroethanesulfonyl chloride with different imines under very mild conditions. The products were obtained in yields up to 75%, and in cis/trans ratios ranging from 59:41 to 12:78. [ABSTRACT FROM AUTHOR]

Two bent-shaped imines (9E)-N-(3-((E)-(4-hexadecylphenylimino)methyl)benzylidene)-4-hexadecylbenzenamine (SL1) and (10E)-N-(3-((E)-(4-(perfluorooctyl)phenylimino)methyl)benzylidene)-4-(perfluorooctyl)benzenamine (SL2) were prepared by condensation reaction in N,N-dimethylacetamide to study their thermal, structural and electrochemical properties, as well as their mixtures with titanium dioxide. Chemical structure, temperature and TiO2 influences on the phase transition temperatures, enthalpy, texture and molecular dynamics of both imines were investigated by differential scanning calorimetry, polarising optical microscopy and Fourier transform middle-infrared absorption spectroscopy during heating and cooling. Changes in the surface morphology of the imines and their mixtures with TiO2 were registered by atomic force microscopy. X-ray study showed the tendency to form lamellas in the case of SL2 as an effect of the presence of two terminal perfluorinated alkyl chains connected to a polar mobile aromatic core, which resulted in microsegregation. Additionally, TiO2 influences the energy gap and HOMO-LUMO levels of imines as was detected by cyclic voltammetry. Finally, devices with two types of architectures, such as ITO/TiO2/SL1(or P3HT)/Au and ITO/TiO2/SL1:P3HT/Au were constructed and investigated under irradiation intensity of 97.7 mW/cm2. [ABSTRACT FROM AUTHOR]

One-pot synthesis of α-aminophosphonates directly from aryl nitro compounds, aldehydes/ketones, and diethyl phosphite using sodium dithionite through reduction and followed by Kabachnik-Fields reaction under metal-free conditions is reported. The major advantages are excellent yield, high chemoselectivity, neutral reaction medium, and simple experimental procedure. This methodology consists of the following steps: 1) amine formation from nitro compound, 2) imine formation from amine and aldehyde/ketone, 3) phosphate addition to imine. [ABSTRACT FROM AUTHOR]

The inhibition capability of an imine compound named (2-methoxyphenyl)-N-(2-(phenylthio)phenyl)methanimine (MPM) on low carbon steel corrosion in HCl solution was investigated at various concentrations and temperatures by using electrochemical and microscopic techniques. The electrochemical results revealed that the inhibition efficiency increases with an increase in the MPM concentration, and MPM has provided 98.8% protection for 120 h. Electrochemical studies at different potentials showed that electrostatic effects have an important role on the adsorption of MPM on the metal surface. scanning electron microscopy and energy-dispersive X-ray spectroscopy results also confirmed that MPM has reduced the corrosive effect of HCl. [ABSTRACT FROM PUBLISHER]

A new piperazine imine, (7E)-N-((4-((E)-(4-hexadecylphenylimino)methyl) piperazin-1-yl)methylene)-4-dodecylbenzenamine, has been synthesized by the condensation of 1,4-piperazinedicarboxaldehyde with 4- hexadecylaniline. The imine was characterized by cyclic voltammetry, Fourier transform middle-infrared absorption spectroscopy and X-ray diffraction. Thermal properties of imine was analyzed by differential scanning calorimetry method during first and second heating scan at 10 and 20 °C/min. Texture of imine was investigated by polarized optical microscopy and atomic force microscopy. Furthermore, imine was blended with titanium dioxide in anatase form and fully characterized by the same methods. Piperazine imine and its mixture with titanium dioxide exhibited only a transition from crystal to isotropic state. Imine exhibits two-step reduction wave attributed to one-electron transfer in each step as was found by cyclic voltammetry. Both titanium dioxide and poly(3-hexylthiophene) change the electrochemical properties of piperazine imine, however, in different ways. Studied imine blended with titanium dioxide exhibited higher value of energy band gap than pure piperazine imine and lower Eg than pure poly(3-hexylthiophene). [ABSTRACT FROM AUTHOR]

NaHSO4 supported on silica gel catalyzes the aza-Diels–Alder reaction of o-hydroxybenzaldimines with 2,3-dihydrofuran to provide furanobenzopyrans in reasonable yields and diastereoselectivity. The catalyst is recyclable and reusable up to two times without a significant loss of activity. [ABSTRACT FROM AUTHOR]

Stereoselective synthesis of novel monocyclic trans-3-halogenated-4-pyrazolyl- β -lactams 5 is described. The reaction of ketene derived from α -bromo/chloroethanoic acids 4 using POCl3 and Et3N with pyrazolyl substituted imines 3a–d in refluxing toluene resulted exclusive formation of trans- β -lactams through [2 + 2] through cycloaddition reaction. The chemical structures of all the newly synthesized β -lactams were verified on the basis of spectroscopic techniques such as FTIR, 1H NMR, 13C NMR, and elemental analysis (CHN). The trans configuration of β -lactams 5 was assigned with respect to position of C3-H and C4-H. The novel β -lactams 5 are potential synthons for azetidines, aziridines, 3-unsubstituted azetidinones, 3-alkyl-halo-azetidinones, and promising biologically active agents. [ABSTRACT FROM AUTHOR]

The reaction of ethyl 3-chloro-3-(alkylimino)-2-oxopropanoate (obtained from alkyl isocyanides and ethyl 2-chloro-2-oxoacetate) with 1-alkyl-3-arylthioureas (prepared from primary alkylamines andaryl isothiocyanates) in dry MeCN at room temperature affords ethyl 5-(alkylimino)-4-hydroxy-2-(arylimino)-3-alkylthiazolidine-4-carboxylates in moderate to good yields. [ABSTRACT FROM PUBLISHER]

Eight new compounds, M(pyca(CH2)xCOOR)Cl2, M = Pd, Pt; R = Me, Et; x = 2, 3, 5, 11, were prepared. The resulting new complexes were characterized by 1H and 13C NMR spectroscopy and each was also structurally elucidated by X-ray crystallography. The compounds share general structural features, but there are differences in the alignment of the alkyl chain; as the chain lengthens, the chain straightens relative to the plane of the metal complex. For the dodecanoic ester derivatives, a nearly linear alkyl chain was observed. These longer alkyl derivatives show mesogenic behavior. [ABSTRACT FROM AUTHOR]

Efficient zinc-mediated allylation, propargylation, and benzylation of isatin-derived imines were undertaken for the synthesis of 3-substituted 3-aminooxindoles with ≈80% yield. Such alternative approach has efficiently avoided the use of catalysts, severe reaction conditions, multistep procedures, and reaction additives. For exploring and materializing the synthetic utility, different allyl, propargyl, and benzyl bromides were used for generalizing the synthetic route. The structure of the synthesized compounds was established and confirmed by 1H NMR, 13C NMR, FTIR, and mass spectroscopic techniques. [ABSTRACT FROM AUTHOR]

The asymmetric Mannich reaction of 3-substituted-2H-1,4-benzoxazines and acetone catalysed by a crude extract from earthworms is reported. The influence of solvents, water contents, catalyst loading, amounts of substrates and temperature on the reaction was investigated. Yields of up to 51% with enantioselectivities of up to 87% ee were achieved under the optimized conditions. This research promotes the development of earthworm extract as a catalyst in Mannich reaction. [ABSTRACT FROM AUTHOR]

We report the unexpected observation of columnar mesophase formation in a simple 2,7-dibromotetramethoxytriphenylene – by far the most lightly substituted discotic mesogen in this class. This derivative was prepared alongside the 3,6-dibromotriphenylene isomer to demonstrate an alternative, modified synthetic strategy that permits late-stage interchange of alkyl chain substituents. The new method is employed alongside the original route to deliver several new materials, including a conjugated ferrocene–triphenylene–ferrocene triad, a BODIPY–triphenylene–BODIPY triad and a new nematic twin linked through imine bridges. [ABSTRACT FROM AUTHOR]

A highly efficient and milder protocol for the synthesis of dispiro imidazolidines in good yields through 1,3-dipolar cycloaddition of in situ-generated azomethine ylide from different di/tri ketones and secondary amino acids with bisimine has been developed. The structure of all newly synthesized compounds was established by analytical and spectral data. Furthermore, the synthesized compounds were screened for antimicrobial activity by agar well-diffusion method. Some of the synthesized compounds showed appreciable antibacterial activity. [ABSTRACT FROM PUBLISHER]

Two dyes which are 4,5-diazafluoren-9-one-derived diimine ligands and their corresponding Ru(II) bipyridine complexes were synthesized. The structures of all compounds were determined by FTIR, UV–Vis, 1H-NMR, 1C-NMR, and MS spectroscopic data. The photovoltaic and electrochemical properties of these compounds were investigated and the applicability in DSSCs as photosensitizers was studied. The photovoltaic cell efficiencies (PCE) of the devices were 0.36–1.26% under simulated AM 1.5 solar irradiation of 100 mW/cm2, and the highest open-circuit voltage (Voc) reached 0.34 V. When comparing the photovoltaic performance of DSSC devices, efficiency increases L2 < L2-Ru < L1 < L1-Ru. The PCE value of 1.26% was obtained with a DSSC based on L1-Ru under AM irradiation (100 mW/cm2). DSSC based on L1-Ru produced efficiency of 1.26%, whereas DSSC-based L1 exhibited the device performance with efficiency of 0.84% under illumination. These results show that the availability of a π-conjugated bridge and a richer electron donor for photovoltaic performance of the DSSC provides increased efficiency. [ABSTRACT FROM AUTHOR]

Poly(ethylene imine)s (PEIs) have gained enormous attention in designing novel drug delivery systems for cancer treatment. High molecular weight of PEIs such as PEI 25 kD are promising for their drug carrying capacity. However, increased molecular weight is associated with toxicity. Currently, the toxicity evaluation of PEIs is mainly focused on the culture cell models, with very few studies investigating the risk assessmentin vivo. Herein, the systemic evaluation of branched PEI 25 kD and PEI-CyD (PC) composed of low molecular PEI (Mw 600) and β-cyclodextrin (β-CyD) is performed in zebrafish model and endothelial cells. Our finding indicate that exposure of PC and PEI 25 kD can induce high mortality rate, shorten hatching time, promote malformations and cell apoptosis of zebrafish embryos in a dose-dependent manner. Most significantly, the cationic polymer PC and PEI 25 kD can decrease heart rate of zebrafish embryos and down-regulate the expression of heart development-related genes, which demonstrate their cardiovasculature toxicity. In this case, we further investigate the effect of PC on endothelial cells. Indeed, PC can induce endothelial cells dysfunction, including oxidative stress and apoptosis which are involved in cardiovascular diseases. These fundamental studies provide valuable insights into the biocompatible evaluation of PEI based drug carriers. [ABSTRACT FROM AUTHOR]

A simple and efficient synthesis of novel pyrimidine-substituted alkanoate, acetohydrazide, and imines is described. The synthesis of novel ethyl 2-(2,6-dimethylpyrimidin-4-yloxy)acetate (EDMPyA)2was performed through SN2O-alkylation of 2,6-dimethyl-4-hydroxypyrimidine1with ethyl haloacetate. The compound EDMPyA2was subjected to nucleophilic substitution reaction with hydrazine hydrate to afford novel 2-(2,6-dimethylpyrimidin-4-yloxy)acetohydrazide (DMPyAH)3. This DMPyAH3upon condensation with differently substituted carbonyl compounds (aldehydes/ketones) furnished DMPyAH imines (DMPyAH-I)4a–d. These imines can be used for the preparation of uniqueβ-lactams. The structure elucidation of all the newly synthesized compounds was performed using spectroscopy (FT-IR,1H and13C NMR) and elemental analysis (C, H, N). [ABSTRACT FROM AUTHOR]

Three bidentate salicylaldimine nickel complexes containing different long-chain alkyl groups in their ligand backbone were synthesized in good yield. All the bidentate salicylaldimine ligands and their nickel complexes were fully characterized by FT-IR,1H NMR, UV spectroscopies, and mass spectrometry. Three bidentate nickel complexes were evaluated as catalyst precursors in ethylene oligomerization. Upon activation with methylaluminoxane (MAO), the catalytic activity was 5.75 × 105 g/(mol Ni·h) and the oligomers were mainly butenes (52.10%) and octenes (32.63%) for bidentate nickel complex with 1-tetradecyl as core in the ligand backbone (R14-complex) using toluene as solvent. However, bidentate nickel complex with 1-octadecyl as core in the ligand backbone (R18-complex) produced mainly octenes (59.38%) and C10 + olefins (29.01%) and the catalytic activity was 2.23 × 105 g/(mol Ni·h). After activation with ethylaluminum sesquichloride (EASC) in toluene, three nickel complexes yielded mainly C10 + products which contained Friedel-Craft alkylated-toluene, and their catalytic activities were above 1.5 × 106 g/(mol Ni·h). For the bidentate salicylaldimine nickel catalysts with hyperbranched molecules as ligand backbones, the solvent and the reaction conditions had a large effect on catalytic activity as well as oligomerization distribution except the structure of the catalyst and the co-catalyst. [ABSTRACT FROM PUBLISHER]

A novel composite material was prepared by the grafting of tannic acid on polyethylenimine (PEI), which allows an efficient sorption of boron (sorption capacity close to 0.89 mmol B g−1). The encapsulation of this chelating sorbent (finely crushed) facilitates its use (readily solid/liquid separation, use in fixed-bed columns) at the expense of a loss in sorption capacity (proportionally decreased by the introduction of alginate having poor efficiency for boron uptake). Sorption isotherms are modeled using the Langmuir equation, while the kinetic profiles are presented a good fit by pseudo-second order rate equation. In addition, the encapsulating matrix introduces supplementary resistance to intraparticle diffusion, especially when the resin is dried without control: freeze-drying partially limits this effect. The stability (at long-term storage) of the sorbent is improved when the sorbent is stored under nitrogen atmosphere. The presence of an excess of NaCl was investigated. The degradation of the hydrogel (by ion-exchange of Ca(II) with Na(I)) leads to a decrease in the sorption performance of composite material but the action of Ca(II) ions in the solutions re-stabilizes the hydrogel. [ABSTRACT FROM PUBLISHER]

Schiff bases are versatile compounds synthesized from the condensation of primary amino compounds with aldehydes or ketones. The high thermal of many Schiff base and their complexes were useful attributes for their application as catalysts in reactions involving at high temperatures. This thermal behavior of Schiff bases and their complexes was evaluated by TGA/DTG and DTA curves with mass losses related to dehydration and decomposition. This review summarizes the developments in the last decade for thermal analysis of Schiff bases. Therefore, synthesis of Schiff bases and their complexes are reviewed. [ABSTRACT FROM AUTHOR]

In this article, we report synthesis and characterization of a novel homologous series of butyl 4-(4′-(alkoxy)-2-hydroxybenzylideneamino)benzoates, CnLH (n = 6, 8, 10, 12, 14, 16) and their copper(II) complexes. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and powder X-ray diffraction (XRD) studies. The ligands and their copper(II) complexes exhibit wide range of enantiotropic smectic A mesophase as confirmed by their typical optical texture under polarizing microscope. Thermal stability of the compounds is determined by thermo gravimetric analyses. DFT calculations have been performed using GAUSSIAN-09 program at B3LYP level to obtain the stable electronic structure of the ligand and its copper(II) complex. [ABSTRACT FROM PUBLISHER]

N-Butyl-1-deoxynojirimycin (NB-DNJ) derived from imino sugar deoxynojirimycin (DNJ) has been approved for the treatment of Gaucher's disease. Herein, a facile and efficient synthetic procedure for NB-DNJ has been described. Comparing to the methods reported previously, methanesulfonyl group was used as a leaving group for easy displacement upon attack by the imine in the sugar ring, leading to a high yield during the introduction of the n-butyl group. This method can serve as an excellent protocol for the synthesis of DNJ derivatives with a variety of N-alkyl substituents and for large-scale production. [ABSTRACT FROM AUTHOR]

This article presents the synthesis of (2R/2S,4R)-2-aryl-thiazolidine- 4-carboxylic acids via nucleophilic addition of L-Cysteine on aromatic aldehydes involving a yield and time-effective room temperature reaction in an aqueous DMSO medium in the presence of NaHCO3 as a base. The synthesized diastereomers were spectroscopically characterized and quantified for diastereomeric excess by liquid chromatography-mass spectrometry analysis. The impact of the type and position of substituent in aromatic aldehydes on reaction time, % yield, ¹H NMR shift at newly formed chiral center [C(2)-H], and diastereomeric excess (de%) have been investigated. A plausible mechanism for stereoselectivity via an in situ imine intermediate is proposed using real-time IR monitoring of the synthetic reaction based on the significant signals at 1597, 1593 cm−1 for imine (C=N) stretching. The imine mechanism for stereoselectivity was further supported by NMR studies of azomethine 13C NMR signals at 159, 160 δ ppm and by the single crystal structure of hitherto unknown (2S,4R)-3-(tert-butoxycarbonyl)- 2-(2-hydroxyphenyl)thiazolidine-4-carboxylic acid (3a) obtained as a major diastereomer in the synthesis of the butyloxy carbonyl (BOC) derivative of (2R/2S,4R)-2-(2-hydroxyphenyl)thiazolidine-4- carboxylic acid. The significant ortho-OH effect of phenolic hydroxyl group leading to strong hydrogen bondings plays a vital role in the formation of 2S,4R BOC derivative stereoselectively. The frontier molecular orbitals, possible electronic excitations, IR band characterizations, and reactivity parameters of newly reported compound (3a) have been predicted using quantum chemical descriptors from density functional theory. The theoretical exploration of experimental spectra using time-dependent DFT indicated a (π-π*) transition between HOMO and LUMO in the ultraviolet region. [ABSTRACT FROM AUTHOR]

Herein, we explore the coordination of di- and triimine chelators at ruthenium(II) and ruthenium(III) centers. The reactions of 2,6-bis-((4-tetrahydropyranimino)methyl)pyridine (thppy),N1,N2-bis((3-chromone)methylene)benzene-1,2-diamine (chb), andtris-((1H-pyrrol-2-ylmethylene)ethane)amine (H3pym) withtrans-[RuIICl2(PPh3)3] afforded the diamagnetic ruthenium(II) complexcis-[RuCl2(thppy)(PPh3)] (1) and the paramagnetic complexes [mer-Ru2(μ-chb)Cl6(PPh3)2] (2), and [Ru(pym)] (3), respectively. The complexes were characterized by IR, NMR, and UV–vis spectroscopy and molar conductivity measurements. The structures were confirmed by single crystal X-ray diffraction studies. The redox properties of the metal complexes were probed via cyclic- and squarewave voltammetry. Finally, the radical scavenging capabilities of the metal complexes towards the NO and 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radicals were investigated [ABSTRACT FROM AUTHOR]

One-pot mild synthesis of 2-azetidinones was carried out by the reaction of imines and carboxylic acids in dry dichloromethane at room temperature using diphosphorus tetraiodide. It was also applied for synthesis of 3-spiro-2-azetidinones. The synthesized compounds were characterized by analytical and spectral (infrared,1H NMR,13C NMR, and elemental analysis) data. [ABSTRACT FROM AUTHOR]

Convenient synthetic approaches for phosphorus analogs of trifluoro- and trichloroalanine derivatives were developed based on readily accessible N-(α-hydroxytrihaloethyl)carbamates. [ABSTRACT FROM PUBLISHER]

Five Cd(II) complexes with the anion of 5-NO2-salicylaldehydeH (5-NO2-saloH) in the absence or presence of theα-diimine 1,10-phenanthroline (phen), 2,2′-dipyridylamine (dpamH), 2,2′-dipyridine (bipy), or 2,9-dimethyl-1,10-phenanthroline (neoc) were synthesized and characterized as [Cd(5-NO2-salo)2(CH3OH)2] (1), [Cd(5-NO2-salo)2(phen)]·2CH3OH·H2O (2), [Cd(5-NO2-salo)2(dpamΗ)] (3), [Cd3(5-NO2-salo)6(bipy)2] (4), and [Cd(5-NO2-salo)(neoc)(NO3)]2(5). Based on spectroscopic results (IR, UV, NMR), elemental analysis and conductivity measurements an octahedral geometry around cadmium metal ion is suggested, with the 5-NO2-salicylaldehyde ligand having different coordination modes. The structures determined by X-ray crystallography verified neutral mononuclear1–3and trinuclear4. Simultaneous TG/DTG–DTA technique was used to analyze the thermal behavior of1,2,and3. The complexes bind tightly to calf-thymus DNA mainly by intercalation, as concluded by DNA viscosity measurements and exhibit significant displacement of EB from the EB-DNA complex. [ABSTRACT FROM AUTHOR]