cas 4185-69-7, 1-(2,4-dinitrophenyl)pyridinium chloride

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[12]Annulene gemini surfactants: Structure and self-assembly
(Chemical Equation Presented) The long and short of it: Gemini surfactants with a non-Hueckel diaza[12]annulene core have been synthesized (see picture). DFT computations give a minimum-energy conformation with alternate shorter and longer bonds, and with the two N substituents pointing away from each other. Studies on the aggregation of the molecules in water show they encounter packing difficulties, with no evidence for ring/ring interactions at the micelle surfaces.
Shi, Lei,Lundberg, Dan,Musaev, Djamaladdin G.,Menger, Fredric M.
p. 5889 - 5891
(2007)
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Deaminative chlorination of aminoheterocycles
Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
Cornella, Josep,Faber, Teresa,Gómez-Palomino, Alejandro,Ghiazza, Clément
(2021/12/23)

Aggregation?induced emissions in columnar wedge?shaped pyridinium?based ionic liquid crystals
Two series of ILCs derived from wedge?shaped N-phenylpyridiniums 1–2 were prepared and their mesomorphic properties were investigated. The X?ray crystal structure analyses of two single crystals 2-PF6 (n = 12) and 2-NTf2 (n = 12) revealed that bilayer structures induced by H?bonds in the solid state were observed. A complementary dimeric structure induced by H?bonds in such type of wedge?shaped cation (or anion) moiety was attributed to the formation of columnar phases. The type of counter anions has a significant influence on the formation of the mesophase; five counter anions (i.e. X = PF6￣, BF4￣, OTf￣, SCN￣, RSO3￣) induced columnar mesophase. In contrast, anion X = Tf2N￣ as a bulky moiety and less H?bond active sites formed crystal phase. The powder XRD data appeared that the diameter of the hard columnar part increased with the effective ionic radius for different counter ion. A linear correlation plot (R2 = 0.9203) was obtained. All ethanol solutions of compounds 1–2 were detected without any observable signals on photoluminescence. But compounds 2-X will aggregate in the aqueous mixture with high water fractions (?w) needed to turn on their light emission process. Weak PL signals are recorded at ?w w > 50% till it reached to the maximum intensity at ?w ~70%.
Wang, Ren-Tzong,Jane Tsai, Suh-Jen,Lee, Gene-Hsiang,Lai, Chung K.
(2019/10/14)

N-alkylated linear heptamethine polyenes as potent non-azole leads against Candida albicans fungal infections
In this study, eighteen heptamethine dyes were synthesised and their antifungal activities were evaluated against three clinically relevant yeast species. The eighteen dyes were placed within classes based on their core subunit i.e. 2,3,3-trimethylindolenine (5a-f), 1,1,2-trimethyl-1H-benzo[e]indole (6a-f), or 2-methylbenzothiazole (7a-f). The results presented herein imply that the three families of cyanine dyes, in particular compounds 5a-f, show high potential as selective scaffolds to treat C. albicans infections. This opens up the opportunity for further optimisation and investigation of this class compounds for potential antifungal treatment.
Critchley, Megan E.,Lawrence, Clare L.,McKenna, Sean T.,Okoh, Adeyi Okoh,Smith, Robert B.,Vishwapathi, Vinod
supporting information

(2020/07/21)

PROCESS FOR THE PREPARATION OF SODIUM 4-(2-((1E,3E,5E,7Z)-7-(1,1-DIMETHYL-3-(4-SULFONATOBUTYL)-1H-BENZO[e]INDOL-2(3H)-YLIDENE) HEPTA-1,3,5-TRIENYL)-1,1-DIMETHYL-1H-BENZO[e]INDOLIUM-3-YL) BUTANE-1-SULFONATE (INDOCYANINE GREEN)
A process for the preparation of substantially pure Indocyanine green of formula with purity greater than 99.0% is provided. More particularly, the embodiments relate to the process for the preparation of Indocyanine green of formula and its intermediates thereof. It further provides crystalline form I of Indocyanine green of formula and process thereof.
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(2019/11/19)

ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES
The present invention includes novel heteroleptic/homoleptic iridium complexes containing two tridentate ligands, where at least one of the tridentate ligands comprises of pyridinium-derived N-heterocyclic carbene. The compounds of the present invention may be useful for organic electroluminescent devices.
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Paragraph 0136; 0137

(2019/04/05)

Understanding Solvation: Comparison of Reichardt's Solvatochromic Probe and Related Molecular "core" Structures
The compound 2,6-diphenyl-4-(2,4,6-triphenylpyridinium-1-yl)phenolate, p-RB, shows distinct colors in different solvents (solvatochromism). The compound 4-(pyridinium-1-yl)phenolate, p-CB, represents the part of p-RB which is responsible for this phenomenon. We compared the solvatochromism of both compounds and also the structurally related 2-(pyridinium-1-yl)phenolate, o-CB, and (2,4-dimethyl-6-(2,4,6-triphenyl-N-pyridinium-1-yl)phenolate, o-RB. In pure solvents, plots of the empirical solvent polarity parameter [ET(probe), kcal/mol] of the different probes correlate linearly with slopes close to unity. That is, these probes are similarly sensitive to specific and nonspecific interactions with the solvents. The solvatochromism of p-CB and o-CB was studied, for the first time, in binary mixtures of water with dimethyl sulfoxide (DMSO) and 1-propanol (1-PrOH). The dependence of ET(probe) on mixture composition was nonideal due to preferential solvation of the probe by one component of the binary solvent mixture. We treated our solvatochromic data using a solvent-exchange model that considers formation of the complex solvents [HOH···O=S(CH3)2] and [HOH···O(H)-C3H7]. The model applies satisfactorily to our data and shows the importance to solvation of hydrogen-bonding and hydrophobic interactions. The preferential solvation of (more hydrophobic) p-RB is more pronounced than that of p-CB or o-CB. The solvent complex [OH2···O(H)-C3H7] is more efficient than [OH2···O=S(CH3)2] because of more possibilities of hydrogen bonding.
Pires, Paulo A. R.,El Seoud, Omar A.,Machado, Vanderlei G.,De Jesus, Jéssica C.,De Melo, Carlos E. A.,Buske, Jonatan L. O.,Cardozo, Amanda P.
p. 2213 - 2220
(2019/04/01)

Connecting a carbonyl and a π-conjugated group through a: P-phenylene linker by (5+1) benzene ring formation
A benzene ring was formed to connect a carbonyl group of various methyl ketones with a π-conjugated group through a p-phenylene linker. Methyl ketones and streptocyanines were used as the C1 and C5 sources, respectively, in the (5+1) annulation, which could form donor-π-acceptor molecules.
Morofuji, Tatsuya,Kinoshita, Hanae,Kano, Naokazu
supporting information
p. 8575 - 8578
(2019/07/25)

Short Wavelength Inner Filter Technique (SWIFT) in Designing Reactive Fluorescent Molecular Probes
Here, we present a conceptually novel and experimentally straightforward technique for selective analyte detection that uses a combination of commercial fluorophores and simple chemicals. The technique utilizes the well-known inner filter effect (IFE); however, the fluorophore's excitation is performed at wavelengths significantly shorter than its absorption maximum. In the presence of the analyte, the "filter" appears or disappears at the excitation wavelength resulting in the fluorescence turning OFF or ON, respectively. Unlike common probes, our technique allows real-time monitoring of a fluorophore's stability as well as its recycling. We further demonstrate the applicability of this technique in continuing analyte detection as well as vapor analysis.
Baheti, Abhishek,Vigalok, Arkadi
supporting information
p. 12224 - 12228
(2019/08/21)

A versatile synthetic route to the preparation of 15N heterocycles
A robust medium-scale (approximately 3 g) synthetic method for 15N labeling of pyridine (15N-Py) is reported based on the Zincke reaction. 15N enrichment in excess of 81% was achieved with approximately 33% yield. 15N-Py serves as a standard substrate in a wide range of studies employing a hyperpolarization technique for efficient polarization transfer from parahydrogen to heteronuclei; this technique, called SABRE (signal amplification by reversible exchange), employs a simultaneous chemical exchange of parahydrogen and a to-be-hyperpolarized substrate (e.g., pyridine) on metal centers. In studies aimed at the development of hyperpolarized contrast agents for in vivo molecular imaging, pyridine is often employed either as a model substrate (for hyperpolarization technique development, quality assurance, and phantom imaging studies) or as a co-substrate to facilitate more efficient hyperpolarization of a wide range of emerging contrast agents (e.g., nicotinamide). Here, the produced 15N-Py was used for the feasibility study of spontaneous 15N hyperpolarization at high magnetic (HF) fields (7 T and 9.4 T) of an NMR spectrometer and an MRI scanner. SABRE hyperpolarization enabled acquisition of 2D MRI imaging of catalyst-bound 15N-pyridine with 75 × 75 mm2 field of view (FOV), 32 × 32 matrix size, demonstrating the feasibility of 15N HF-SABRE molecular imaging with 2.4 × 2.4 mm2 spatial resolution.
Chukanov, Nikita V.,Kidd, Bryce E.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Shchepin, Roman V.,Chekmenev, Eduard Y.,Goodson, Boyd M.,Kovtunov, Kirill V.,Koptyug, Igor V.
p. 892 - 902
(2019/01/11)

Crystal melting and glass formation in copper thiocyanate based coordination polymers
Crystal melting and glass formation of coordination polymers (CPs) and metal-organic frameworks (MOFs) are rare thermal events. To expand the library of melting CP/MOFs, we utilized anti-crystal engineering in ionic liquids to construct CPs. A combination of Cu+ and 4,4′-bipyridin-1-ium derivatives afforded four melting CPs showing stable liquid and glassy states.
Nagarkar, Sanjog S.,Kurasho, Haruna,Duong, Nghia Tuan,Nishiyama, Yusuke,Kitagawa, Susumu,Horike, Satoshi
supporting information
p. 5455 - 5458
(2019/05/17)

A Convenient Synthesis of Azulene
An improved and scalable synthesis of azulene has been developed by the application of pyrrolidine as a reagent and continuous steam distillation and extraction for workup. Applications for the coloration of perfluorinated media and silicones were demonstrated.
Langhals, Heinz,Ebersp?cher, Moritz
p. 1862 - 1866
(2018/02/09)

Effect of counter ions on the mesogenic ionic: N -phenylpyridiniums
Two series of ionic liquid crystals (ILCs) derived from N-phenylpyridinium 1-2 were prepared and their mesomorphic properties were investigated. A versatile and effective method was developed to prepare these ionic compounds 2-X from their precursor chloride 2-Cl. X-ray crystal structure analyses of three single crystals revealed that a sandwiched head-to-head or bilayer lamellar structure induced by H-bonds in the solid state was observed. The anion was proximally intercalated near the head group. Weak H-bonds were induced and attributed to the formation of mesophases. The type of counter anions has a significant influence on the stability of the mesophase, ΔTSmA = 221.3 (2-Cl) > 213.1 (2-SCN) > 173.9 (2-BF4) > 85.4 (2-RSO3) > 63.8 (2-PF6) > 41.4 °C (2-OTf) for all derivatives with n = 12. The compound 2-BF4 (n = 16) has the widest temperature range of the smectic-A (SmA) phase (i.e., ΔTSmA = 234.3 °C), significantly broader than those of other reported ILCs. Also compound 2-NTf2 (n = 14) was the first phenylpyridinium-based ILC and compound 2-SCN (n = 16) was the room temperature ILC. The X-ray diffraction experiments confirmed the structure of the SmA phase and it showed a strong dependence of bilayer structure with various anions. A linear correlation plot (R2 = 0.9643) of the clearing temperatures of compounds 2-X with the calculated effective radius (Reff) of the anions was obtained.
Wang, Ren-Tzong,Lee, Gene-Hsiang,Lai, Chung K.
p. 2593 - 2607
(2018/05/23)

Dual-Cavity Basket Promotes Encapsulation in Water in an Allosteric Fashion
We prepared dual-cavity basket 1 to carry six (S)-alanine residues at the entrance of its two juxtaposed cavities (289 ?3). With the assistance of 1H NMR spectroscopy and calorimetry, we found that 1 could trap a single molecule of 4 (K1 = 1.45 ± 0.40 × 104 M-1, ITC), akin in size (241 ?3) and polar characteristics to nerve agent VX (289 ?3). The results of density functional theory calculations (DFT, M06-2X/6-31G?) and experiments (1H NMR spectroscopy) suggest that the negative homotropic allosterism arises from the guest forming C-H···π contacts with all three of the aromatic walls of the occupied basket's cavity. In response, the other cavity increases its size and turns rigid to prevent the formation of the ternary complex. A smaller guest 6 (180 ?3), akin in size and polar characteristics to soman (186 ?3), was also found to bind to dual-cavity 1, although giving both binary [16] and ternary [1-62] complexes (K1 = 7910 M-1 and K2 = 2374 M-1, 1H NMR spectroscopy). In this case, the computational and experimental (1H NMR spectroscopy) results suggest that only two aromatic walls of the occupied basket's cavity form C-H···π contacts with the guest to render the singly occupied host flexible enough to undergo additional structural changes necessary for receiving another guest molecule. The structural adaptivity of dual-cavity baskets of type 1 is unique and important for designing multivalent hosts capable of effectively sequestering targeted guests in an allosteric manner to give stable supramolecular polymers.
Chen, Shigui,Yamasaki, Makoto,Polen, Shane,Gallucci, Judith,Hadad, Christopher M.,Badji?, Jovica D.
supporting information
p. 12276 - 12281
(2015/10/12)

Reagent and method for detection of carboxylic acids by mass spectrometry
Method and reagent for converting a carboxylic acid to a positively charge amide are described. The method and reagent facilitate positive ion mass spectral analysis of carboxylic acids. The method includes reacting a carboxylic acid with a compound having formula I: wherein A and B are aromatic rings, ring A includes a quaternized nitrogen and has n additional ring atoms, each additional ring atom optionally substituted with an RA group, and n is an integer from 4 to 10, and ring B includes a carbon atom and has m additional ring atoms, each additional ring atom optionally substituted with an RB group, and m is an integer from 4 to 10. The compound includes at least one RA or RB group, and the at least one RA and RB group is -L-N(Z)H; and X? is a counterion.
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(2015/06/09)

A Synthesis of Alsmaphorazine B Demonstrates the Chemical Feasibility of a New Biogenetic Hypothesis
An N-oxide fragmentation/hydroxylamine oxidation/intramolecular 1,3-dipolar cycloaddition cascade efficiently converted an oxidized congener of akuammicine into the complex, hexacyclic architecture of the alsmaphorazine alkaloids. This dramatic structural change shows the chemical feasibility of our novel proposal for alsmaphorazine biogenesis. Critical to these endeavors was a marked improvement in our previously reported Zincke aldehyde cycloaddition approach to indole alkaloids, which permitted the gram-scale synthesis of akuammicine. The chemoselective oxidations of akuammicine leading up to the key rearrangement also generated several biogenetically related alkaloids of the alstolucine and alpneumine families.
Hong, Allen Y.,Vanderwal, Christopher D.
supporting information
p. 7306 - 7309
(2015/06/30)

Charge-Assisted Halogen Bonding in Bromo- and Iodophenylpyridinium Chlorides
Ten N-halophenylpyridinium salts (halogen = Br or I) with chloride (and in one case iodide) counterions have been prepared and structurally characterized in order to examine the degree of solid state halogen bonding exhibited in these systems. N-Halophenylpyridinium salts are easily synthesized from existing pyridines, and the cationic pyridinium group is expected to increase the halogen bond donor ability of attached halophenyl moieties. Halide anions functioning as halogen bond acceptors facilitate formation of charge-assisted halogen bonds. All five substrates featuring iodophenyl or diiodophenyl substituents displayed the expected halogen bonding interactions. In several cases halide ion acceptors were also engaged in complementary hydrogen bonding interactions with C-H groups of pyridinium rings and O-H groups of water solvates. Halogen bond donors containing a diiodophenyl group formed either an extended network or discrete supramolecular macrocyclic constructs through ArI...Cl-...IAr bridging interactions. Significantly fewer and weaker halogen bonding interactions were observed in crystals of N-bromophenylpyridinium salts. The attenuation of halogen bonding in these substrates is attributed to the inability of the activated bromoarene halogen bond donors to compete with hydrogen bond donors (C-H/O-H residues) for the halide anion. (Chemical Equation Presented).
Kassl, Christopher J.,Swenson, Dale C.,Pigge, F. Christopher
p. 4571 - 4580
(2015/09/15)

Promising near-infrared non-targeted probes: Benzothiazole heptamethine cyanine dyes
A series of benzothiazole heptamethine cyanine dyes have been synthesized and their photophysical properties evaluated in relation to their structural features. These have been compared against two classical probes of this type: Indocyanine Green (IGC) and New Indocyanine Green (IR-820). Growth inhibitory studies were also performed using a eukaryotic, unicellular organism, fission yeast Schizosaccharomyces pombe. Herein we highlight some potentially interesting candidates with improved fluorescence quantum yields when compared with ICG and IR-820.
Okoh, Okoh Adeyi,Bisby, Roger H.,Lawrence, Clare L.,Rolph, Carole E.,Smith, Robert B.
p. 42 - 56
(2014/01/06)

PROCESS FOR DYE PRODUCTION
The present invention relates to a process for the production of certain compounds, especially dye compounds defined in general by Formula I: The invention provides a one-step method in which a compound of Formula II or a reactive intermediate derived in situ therefrom is reacted in situ with a compound of Formula III (optionally in the presence of a compound of Formula IV) to produce compounds of Formula I in excellent yield, and in a manner which avoids undesirable by- product formation.
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(2013/08/15)

Efficient synthesis of various 4-tosyloxy-2-substituted phenols using pyridinium salt-supported [hydroxy(tosyloxy)iodo]benzene reagent
A novel pyridinium salt-supported [hydroxy(tosyloxy)-iodo]benzene (HTIB) reagent (N-{4-[hydroxy(tosyloxy)iodo]-phenyl}pyridinium hexafluorophosphate) was prepared via Zincke's reaction. The conjugated HTIB was an effective reagent for tosyloxylation of phenolic aromatic rings with an electron-withdrawing substitute at the ortho-position. The reagent can be easily regenerated in high yield and reused three times without any decrease in activity.
Yang, Bing,Zhang, Jizhen,Zhao, Dejian,Wang, Yazhen,Jia, Hongbin
supporting information
p. 930 - 932
(2013/09/02)

An efficient ultrasonic-assisted synthesis of imidazolium and pyridinium salts based on the Zincke reaction
A mild and efficient method has been developed using ultrasound irradiation for the synthesis of imidazolium and pyridinium salts based on the Zincke reaction. Tertiary nitrogen nucleophiles such as pyridines and imidazoles can be alkylated with primary amine by simply using their ammonium form Zincke salts. In almost all cases, a clear yield increase results and a dramatic reduction of the reaction time accompanied by an improved quality of the products occurs.
Zhao, Sanhu,Xu, Xiaoming,Zheng, Lu,Liu, Hai
experimental part
p. 685 - 689
(2011/02/23)

Photochromic behavior of several new synthesized dyes via Zincke salts
Synthesis of several 'dyes', analogs of retinal imine visual pigment via nucleophilic attack of some secondary amines to pyridinium salts following precyclic ring-opening reaction, is discussed. The photochromic properties of these dyes have been studied by UV-Vis spectroscopy under irradiation of UV light. Copyright
Mahmoodi,Mamaghani,Ghanadzadeh,Arvand,Fesanghari
experimental part
p. 266 - 270
(2010/09/07)

Improved sensitivity mass spectrometric detection of eicosanoids by charge reversal derivatization
Combined liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) is a powerful method for the analysis of oxygenated metabolites of polyunsaturated fatty acids including eicosanoids. Here we describe the synthesis of a new derivatization reagent N-(4-aminomethylphenyl) pyridinium (AMPP) that can be coupled to eicosanoids via an amide linkage in quantitative yield. Conversion of the carboxylic acid of eicosanoids to a cationic AMPP amide improves sensitivity of detection by 10- to 20-fold compared to negative mode electrospray ionization detection of underivatized analytes. This charge reversal derivatization allows detection of cations rather than anions in the electrospray ionization mass spectrometer, which enhances sensitivity. Another factor is that AMPP amides undergo considerable collision-induced dissociation in the analyte portion rather than exclusively in the cationic tag portion, which allows isobaric derivatives to be distinguished by tandem mass spectrometry, and this further enhances sensitivity and specificity. This simple derivatization method allows prostaglandins, thromboxane B2, leukotriene B4, hydroxyeicosatetraenoic acid isomers, and arachidonic acid to be quantified in complex biological samples with limits of quantification in the 200-900 fg range. One can anticipate that the AMPP derivatization method can be extended to other carboxylic acid analytes for enhanced sensitivity detection.
Bollinger, James G.,Thompson, Wallace,Lai, Ying,Oslund, Rob C.,Hallstrand, Teal S.,Sadilek, Martin,Turecek, Frantisek,Gelb, Michael H.
experimental part
p. 6790 - 6796
(2011/04/25)

Synthesis of N-arylpyridinium salts bearing a nitrone spin trap as potential mitochondria-targeted antioxidants
The generation of excess reactive oxygen species (ROS) in mitochondria is responsible for much of the oxidative stress associated with ageing (aging), and mitochondrial dysfunction is part of the pathology of neurodegeneration and type 2 diabetes. Lipophilic pyridinium ions are known to accumulate in mitochondria and this paper describes a general route for the preparation of nitrone-containing N-arylpyridinium salts having a range of lipophilicities, as potential therapeutic antioxidants. The compatibility of nitrones with the Zincke reaction is the key to their synthesis. Their trapping of carbon-centred radicals and the EPR spectra of the resulting nitroxides are reported.
Robertson, Linsey,Hartley, Richard C.
experimental part
p. 5284 - 5292
(2009/11/30)

Complex polycyclic lactams from pericyclic cascade reactions of Zincke aldehydes
(Chemical Equation Presented) In the course of a simple mechanistic study on the rearrangement of Zincke aldehydes to Z-α,β,γ,δ- unsaturated amides, a thermally induced pericyclic cascade rearrangement that converts Zincke aldehydes derived from allylic and homoallylic amines into polycyclic lactams was discovered. The key reaction involves an E-Z alkene isomerization, a 6? electrocyclic ring closure, a[1,5]-sigmatropic shift of hydrogen, a 6? electrocyclic ring-opening , and a Diels-Alder cycloaddition, and proceeds with excellent stereoselectivity. The unusual observation that furans and an indole serve as dienophiles in this cascade reaction permitted the synthesis of complex, functional group-rich tri- and tetracyclic lactams. In all cases, the rigid polycyclic products are available in only two steps from pyridinium salts and the allylic or homoallylic secondary amines.
Steinhardt, Sarah E.,Vanderwal, Christopher D.
supporting information; scheme or table
p. 7546 - 7547
(2009/10/17)

Synthesis of δ-tributylstannyl-α,βγ, δ-unsaturated aldehydes from pyridines
(Equation Presented) Zincke aldehydes, which are readily available from the ring-opening reaction of pyridinium salts, are easily converted into δ-tributylstannyl-α,β,γ,δ-unsaturated aldehydes (stannyldienals) by the action of tributylstannyllithium. This reaction appears to proceed via 1,6-stannyllithium addition/elimination of lithium dialkylamide. Several stannyldienals of significant utility for the synthesis of polyene natural products have been made by this route, which proceeds in modest yields, but is successful on multigram scale using inexpensive reagents. Simple stannylenals and stannylenones are similarly available from the corresponding vinylogous amides.
Michels, Theo D.,Rhee, Jong Uk,Vanderwal, Christopher D.
supporting information; experimental part
p. 4787 - 4790
(2009/05/07)

Palladate salts from chiral pyridinium ionic liquids: Synthesis and crystal structures
This paper reports the preparation, characterization and the crystal X-ray structures of metal-containing ionic liquid complexes based on chiral pyridinium cations and tetrachloropalladate (II) [PdCl4]2-.
Tourneux, Emmanuel,Gornitzka, Heinz,Marty, Jean-Daniel,Lauth-De Viguerie, Nancy
p. 1940 - 1949
(2008/02/11)

Microwave-promoted synthesis of chiral pyridinium salts
The synthesis of several chiral pyridinium salts via Zincke's reaction can be easily accomplished by domestic microwave oven irradiation. Yield enhancements, reduction of reaction time, and less racemization were observed under microwave heating when compared to conventional heating in similar conditions.
Viana, Gustavo H. R.,Santos, Itamar C.,Alves, Rosemeire B.,Gil, Laurent,Marazano, Christian,Gil, Rossimiriam P. F.
p. 7773 - 7776
(2007/10/03)

New pyridinium chiral ionic liquids
New pyridinium chiral ionic liquids have been synthesised from the corresponding pyridine and chiral primary amines. The physical properties of these salts were determined; one of the salts is a room-temperature ionic liquid thermally stable up to 215 °C and suitable for organic synthesis.
Patrascu, Cosmin,Sugisaki, Claudia,Mingotaud, Christophe,Marty, Jean-Daniel,Génisson, Yves,De Viguerie, Nancy Lauth
p. 2033 - 2041
(2007/10/03)

The Solid-Phase Zincke Reaction: Preparation of ω-Hydroxy Pyridinium Salts in the Search for CFTR Activation
A study of structural modifications of MPB-07 was undertaken as part of a synthetic program aimed at discovering small molecules with CFTR activation potential. Solid-phase synthesis techniques were used to prepare derivatives of MPB-07 employing the Zincke reaction for the construction of aromatic, quaternary ammonium salts such as those found in 2 or 3. In this transformation, primary amines react with highly electrophilic N-2,4-dinitrophenylpyridinium (DNP) salt 4 to afford pyridinium salt 8 with release of 2,4-dinitroaniline 6. Thus, the reaction of 1-(2,4-dinitrophenyl)pyridinium salts with various polymer-bound amino ethers, followed by cleavage from the resin, delivers the desired salts in good yield and high purity.
Eda, Masahiro,Kurth, Mark J.,Nantz, Michael H.
p. 5131 - 5135
(2007/10/03)

The Zincke's reaction: A new alternative for the preparation of 1-[2- (3-indol)ethyl]-alkylpyridinium chloride derivatives
The Zincke's salts 3 (a-f) were prepared and used for the synthesis of 1-[(2-(3-indol)-ethyl]alkylpyridinium chloride derivatives 5 (a-f) in high yields.
Gnecco, Dino,Juarez, Jorge,Galindo, Alberto,Marazano, Christian,Enriquez, Raul G.
p. 281 - 287
(2007/10/03)

Nucleophilic additions to N-nitro- and N-(2,4-dinitrophenyl)-pyridinium salts
The reactive N-nitropyridinium nitrate (2) and the stable N-(2,4-dinitrophenyl)-pyridinium chloride (5) have been reacted with nucleophiles. N-Nitropyridinium nitrate and pyridine gave 4-pyridino-1-nitro-1,4-dihydropyridine (3) in an equilibrium reaction. With hydroxide ions, a ring-opening reaction took place to give 5-nitroaminopenta-2,4-dienal (4) which gave back 2 upon acidification. N-(2,4-Dinitrophenyl)pyridinium chloride reacted with sodium sulfite to give a mixture of two products, one from attack of two sulfite ions on the dinitrophenyl ring (7) and one from attack in the 4-position of the pyridinium ring (6). The ratio 7/6 increased with increasing polarity of the reaction medium. N-(2,4-Dinitrophenyl)pyridinium chloride also reacted with nitromethanide ion to give N-(2,4-dinitrophenyl)-4-nitromethyl-1,4-dihydropyridine (9). This compound reacted with NO2BF4 to give the N-(2,4-dinitrophenyl)-4-nitromethylpyridinium ion (10). Acta Chemica Scandinavica 1998.
Andersen, Espen,Bakke, Jan M.,Ranes, Eli,Riha, Jaroslav
p. 350 - 356
(2007/10/03)

Synthesis of Some N-(Phenylsulfonylamino)-1,2,3,6-tetrahydropyridines as Potential Anti-inflammatory Agents
Several N-(phenylsulfonylamino)-1,2,3,6-tetrahydropyridines were synthesized by substituting a sulfonyl group for the carbonyl group of N-(phenylcarbonylamino)-1,2,3,6-tetrahydropyridines 1 in order to investigate the effect of the substitution on the analgesic and anti-inflammatory activities. Nucleophilic attack of pyridine derivatives 2 on 1-chloro-2,4-dinitrobenzene 3 furnished the pyridinium chlorides 4. Compound 4 and benzenesulfonyl hydrazide 5 were reacted to give the 2,4-dinitroanilino derivatives 6. Hydrolysis of 6 furnished the ylides 7. Sodium borohydride reduction of ylides afforded the tetrahydropyridines 8. Compound 8c was found to be the most active anti-inflammatory agent and was as potent as indomethacin, the reference compound. Compound 8f had the most significant hyperglycemic activity.
Choi, JongOh,Wilson, Tiffany L.,Ly, Ana M.,Okoro, Cosmas O.,Onubogu, Udobi C.,Redda, Kinfe K.
p. 281 - 295
(2007/10/03)

Benzpyrylium dyes, and processes for their preparation and use
4-[3-(benz[b]pyran-4-ylidene)prop-1-enyl]benz[b]pyrylium, 4-[5-(4H-benz[b]pyran-4-ylidene)penta-1,3-dienyl]benz[b]pyrylium and 4-[7-(4H-benz[b]pyran-4-ylidene)hepta-1,3,5-trienyl]benz[b]pyrylium dyes, wherein at least one of the benzpyrylium nuclei carries at its 2-position a substituent in which a non-aromatic carbon atom is bonded directly to the benzpyrylium nucleus, subject to the proviso that if the or each 2-substituent contains an aromatic nucleus, this aromatic nucleus is not conjugated with the benzpyrylium nucleus, are useful as visible and near infra-red absorbers, having high extinction coefficients and a reduced tendency to develop absorptions at shorter wavelengths when dispersed in polymeric media.
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(2008/06/13)

Reactivity of some Aromatic Heterocyclic Tertiary Amines in Quaternization with 1-Chloro-2,4-dinitrobenzene
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Gerez, Maria do Carmo A.,Miller, Joseph,Moran, Paulo J. S.
p. 3072 - 3083
(2007/10/02)

Rections of Porphyrins with Nitronium Tetrafluoroborate in Pyridine
Octaethylporphyrin reacts with nitronium tetrafluoroborate in pyridine at 80 deg C to afford the meso-nitroporphyrin in 31percent yield after 6 h, whereas the zinc complex reacts very rapidly at 20 deg C to afford 63percent of the meso-nitroporphyrin after work-up. meso-Tetraphenylporphyrin, however, only reacted slowly with nitronium tetrafluoroborate in pyridine at rather higher temperatures in a sealed tube to afford the β-pyridinium salt of the porphyrin as the major product; again when the zinc complex of tetraphenylporphyrin was used the β-pyridinium salt was formed in 85percent yield in a few minutes at 20 deg C.Brief treatment of the tetraphenylporphyrin pyridinium salt with alkali afforded a ring-opened glutaconaldehyde derivative of the β-aminoporphyrin, analogous to the well-known Zincke's compounds which can be obtained from N-arylpyridines with alkali.The structures of both the ring-opened products from the pyridinium porphyrin and from N-(2,4-dinitrophenyl)pyridinium chloride, were assigned by highfield n.m.r. spectroscopy, including decoupling and n.O.e. difference measurements.
Cavaleiro, Jose A. S.,Neves, Maria G. P. M. S.,Hewlins, Michael J. E.,Jackson, Anthony H.
p. 575 - 580
(2007/10/02)

Azulene
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Hafner, Klaus,Meinhardt, Klaus-Peter
p. 134 - 134
(2017/05/20)

DERIVATIVES AND REACTIONS OF GLUTACONALDEHYDE-XIII. REGIOSPECIFIC RING OPENING OF 3-SUBSTITUTED PYRIDINES
A number of nucleophilic ring openings of 3-substituted pyridinium salts have been reinvestigated and summarized.The structure of the resulting stable glutaconaldehyde derivatives was investigated in detail by 1H NMR.It has been concluded that in general nucleophilic pyridinium ring openings are highly regiospecific.In each case investigated to date a single product was isolated, as a result of attack by the nucleophile at only one of the pyridine α-positions.With the OH ion as the only nucleophile, attack occurs at the pyridine C-2, while larger nucleophiles such as amines and carbanions attack at the pyridine C-6.This was found to be the case for a variety of 3-substituted pyridines such as 3-methyl-, 3-methoxy-, 3-cyano-, 3-chloro-pyridine.
Becher, Jan,Finsen, Lars,Winckelmann, Ib
p. 2375 - 2378
(2007/10/02)