Understanding the Charge Issues in Mono and di-Quaternary Ammonium Compounds for Their Determination by LC/ESI-MS/MS

Chromatographers often develop problems while optimizing a method for the quantification of quaternary ammonium compounds in ESI-MS/MS. Intransigency observed in quaternary ammonium compounds to undergo the classical molecular adduct formation [M+H]⁺ in ESI-MS/MS reduces confidence among chromatographers while working with unit mass resolution. In this study, we provide the evidence for an exceptional rule followed by mono- and di-quaternary ammonium compounds in ESI-MS/MS in the precursor ion formation. Under ESI conditions mono- and di-quaternary ammonium compounds form molecular ions with the formula of m ^q / z ^q rather than ( m + z )/ z . Formation of m ^q / 2 is observed for di-quaternary ammonium compounds in precursor ion scan and m ^q / 1 in product ion scan, if loss of one of the quaternary charge occurs during CID. In di-quaternary ammonium compounds, this process can also result in the formation of fragment ions with higher mass as compared to precursor ion. Hydrophilic interaction liquid chromatographic separation has been used to demonstrate the elution of quaternary ammonium compounds in a single run in the ESI-MS/MS. This work concludes that the analyst must realize and consider these charge issues while dealing with positively charged compounds in LC/ESI-MS/MS.     

Convenient,Cost‐Effective,and Mild Method for the N‐Acetylation of Anilines and Secondary Amines

Abstract

An efficient, cost‐effective, and mild method for the N‐acetylation of anilines and secondary amines with ammonium acetate in acetic acid media at reflux temperature in good yield is described.     

Synthesis,spectral characterization,and evaluation of antimicrobial activity of O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and zinc bis(O,O′-alkanediyl) dithiophosphates

The synthesis of novel dithiophosphate derivatives has been achieved. Two O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and two Zinc bis(O,O′-alkanediyl) dithiophosphates are synthesized by an easy and facile chemical synthetic route. Zinc bis[O,O′-(2-methylpentane-2,4-diyl) dithiophosphate] L¹, Zinc bis[O,O′-(2-ethylhexane-1,3-diyl) dithiophosphate] L², O,O′-(2-methylpentane-2,4-diyl) S-(N-phthalimidomethyl) dithiophosphate L³ and O,O′-(2-ethylhexane-1,3-diyl) S-(N-phthalimidomethyl) dithiophosphate L⁴ are synthesized from the respective ammonium salts. Compounds L¹, L², L³, and L⁴ are characterized by (CHN) elemental analysis, ESI mass, FT-IR, ¹H, ¹³C, and ³¹P NMR techniques. The crystal structure of ammonium O,O′-(2-methylpentane-2,4-diyl) dithiophosphate is discussed. L¹, L², L³, and L⁴ were evaluated for antimicrobial activity. It was found that the phthalimide derivatives L³ and L⁴ showed much better antifungal potential against some species of fungus. The Zinc dithiophosphates L¹ and L² showed good antibacterial activity against Bacillus cereus and Escherichia coli.     

THE CRYSTAL STRUCTURES OF AMMONIUM AND SODIUM 2-AMINO-3,5-DICHLOROBENZOATES

Abstract

The crystal structures of ammonium and sodium 2-amino-3,5-dichlorobenzoates were determined by the X-ray diffraction method. The ammonium salt crystallizes in the monoclinic system (space group P2₁/c) with a = 13.941(3), b = 9.128(3), c = 7.349(2) Å, β = 90.80(3)° and Z = 4. The structure consists of an ammonium cation hydrogen bonded to a carboxylate oxygen of the 2-amino-3,5-dichlorobenzoate anion. The sodium salt of 2-amino-3,5-dichlorobenzoic acid crystallizes in the triclinic system (space group P 1) with a = 8.033(2), 6 = 8.944(2), c = 17.350(3) Å, α = 76.72(3)°, β = 79.69(3)°, γ = 72.54(3)° and Z = 4. The compound is a polymer in which the sodium ions are coordinated by carboxylate oxygen atoms of the organic ligand and water molecules in an octahedral arrangement. IR spectra of the salts are discussed.     

A convenient access to 2,4-disubstituted quinazolines via one-pot three-component reaction under mild conditions†

Abstract

A new and practical method has been developed for the synthesis of 2,4-disubstituted quinolines via one-pot three-component reaction of o-amino arylketones, aldehydes and ammonium acetate in high yields by using DDQ in CH₃CN under mild conditions. Neutral conditions, atom economy, easy work-up procedures and compatible with different functional groups are the salient features of this protocol.     

Reindarstellung von Lanthan- und Praseodym-Ammoniumdoppelnitraten durch fraktionierte Kristallisation in großem Maßstab

Summary Lanthanum ammonium nitrate of purity 97%, containing 34.1 kgRE ₂O₃, was crystallized fractionally and yielded 32.5 kg oxide of purity better than 99.9% (the larger part was 99.99% pure). Out of mixtures with 66% Pr there resulted praseodymium ammonium nitrate containing 13.45 kg oxide of purity better than 99.5%. The effective separation factors are discussed, showing a better efficiency of the ammonium than of the magnesium double nitrates for the separation of praseodymium and lanthanum.

     

Alkyl Ammonium Ion Selectivity of Hexahomotrioxacalix[3]arene Triamide Derivative having the Intramolecular Hydrogen-Bonding Group

The lower rim functionalized hexahomotrioxacalix[3]arene triamide 4 with cone-conformation was synthesized from triol 1 by a stepwise reaction. The different extractability for alkali metal ions, transition metal ions, and alkyl ammonium ions from water into dichloromethane is discussed. Due to the strong intramolecular hydrogen bonding between the neighboring NH and CO groups in triamide 4, its affinity to metal cations was weakened. Triamide 4 shows a single selectivity to n-BuNH₃⁺. The anion complexation of triamide 4 was also studied by ¹H NMR titration experiments. Triamide 4 binds halides through the intermolecular hydrogen bonding among the NH hydrogens of amide in a 1:1 fashion in CDCl₃. The association constants calculated from these changes in chemical shifts of the amide protons are K_a = 223 M⁻¹ for Cl⁻ and K_a = 71.7 M⁻¹ for Br⁻. Triamide 4 shows a preference for Cl⁻ complexation than Br⁻ complexation.     

Crystal Structures of (18-Crown-6)-(2-Hydroxyethylammonium) Tetracyanonickelate(Ii) and 10-Amino-Decylammonium Tetracyanonickeltate(II)

Abstract

The crystal structures of the two title tetracyanonickelate(II) salts of organic ammonium ions, (18-crown-6)-(2-hydroxyethylammonium) tetracyanonickelate(II), I, and 10-aminodecylammonium tetracyano nick-elate(II), II, have been analyzed. I crystallizes in the monoclinic space group P2₁/n with a = 10.458(2), b = 8.267(3), c = 24.045(2) Å, β = 94.09(1)°, V = 2074(1) ų, Z = 2, R = 0.061 for 2274 reflections; II is triclinic P ₁ with a = 9.437(3), b = 10.094(3), c = 9.205(3)Å,a = 110.16(2), β = 112.72(3), γ = 69.16(2)°, V = 733.7(5) ų 2=1, R = 0.040 including all the hydrogen atoms refined for 2724 reflections. The square planar tetracyanonickelate(II) anion is in a favourable position to form hydrogen bonds via N with the hydroxyl group in I and the ammonio group in II, respectively.     

Efficient α-Thiocyanation of Ketones Using Pyridinium Hydrobromide Perbromide

Abstract

The direct α-thiocyanation of ketones with ammonium thiocyanate has been achieved using pyridinium hydrobromide perbromide under mild and neutral conditions to produce α-ketothiocyanates in excellent yields and with high selectivity.     

2-氨基-4,6-二芳基吡啶的微波辐射促进合成

氯化N-氰甲基吡啶在微波辐射下于醋酸铵/醋酸体系中和4种查尔酮反应, 或直接与芳香醛和取代苯乙酮一锅煮反应, 高产率地生成了2-氨基-4,6-二芳基吡啶衍生物. 化合物的结构经过IR, ¹H NMR和HPLC-MS的表征.     

A Solid Ammonium Ion Selective Electrode

Abstract

A new ammonium ion selective electrode has been developed and found to be capable of measuring ammonium ion in the presence of other cations. The electrode's selectivity over other cations is reported as well as its response time to step changes in ammonium ion activity. In addition, blood serum samples have been analyzed for urea content by treatment with urease with no special sample pre-treatment required.     

Synthesis of quaternary ammonium tribromides: a novel green approach

Abstract

Potassium permanganate (KMnO₄) oxidizes quaternary ammonium bromides to the corresponding tribromides conveniently and effectively. The procedure adopted is environmentally friendly as it is solvent-free. High purity, excellent yield, shorter reaction time and mild reaction conditions are some of the advantages of this synthetic protocol. The efficacy of quaternary ammonium tribromides, especially benzyltrimethylammonium tribromide, is also studied for bromination of some organic substrates.     

Electron transfer reactions of 1-phenyl-4-vinylpyrazole mediated by cerium(IV) ammonium nitrate

Summary The title compound is converted into the cyclic ethers5 and the alcohol6 upon treatment with ceric ammonium nitrate in acetone. Using methanol as a solvent the dimethoxy derivative9 and the nitrate ester10 are formed. No cross cycloaddition is observed in the presence of olefins such as ethyl vinyl ether,DMAD, or indene; however, with cyclopentadiene as co-reagent a mixture of the exo-endo Diels-Alder adducts14 involving the vinylic system of 1 as 2 component is obtained. The results are rationalized through the interrnediacy of the radical cation1 ^·+, generated by single electron transfer (SET) from the neutral precursor1 to Ce(IV).

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Elektrontransfer-Reaktionen von 1-Phenyl-4-vinylpyrazol mittels Cer(IV)-Ammonnitrat

Zusammenfassung Die Titelverbindung wurde mittels Cer(IV)-Ammonnitrat in Aceton in die cyclischen Ether5 und den Alkohol6 umgewandelt. Mit Methanol als Lösungsmittel wurde das Dimethoxyderivat9 und der Nitratester10 gebildet. Bei Anwesenheit von Olefinen wie etwa Ethylvinylether,DMAD oder Inden wurden keine Cross-Cycloadditionen beobachtet. Hingegen wurde mit Cyclopentadien als Mitreagens eine Mischung vonexo-endo-Diels-Alder-Produkten14 erhalten, wobei das vinylische System von1 als 2-Komponente fungiert. Die Ergebnisse werden mittels eines intermediär auftretenden Radikalkation1 ^·+ als Produkt eines Einelektronentransfers (SET) des neutralen Vorläufers1 zu Ce(IV) rationalisiert.

     

On the Importance of H-Bonding Interactions in Organic Ammonium Tetrathiotungstates

Summary. Four new organic ammonium tetrathiotungstates (N–Me–enH₂)[WS₄] (1), (N,N′-dm-1,3-pnH₂)[WS₄] (2), (1,4-bnH₂)[WS₄] (3), and (mipaH)₂[WS₄] (4), (N–Me–enH₂ = N-methylethylenediammonium, N,N′-dm-1,3-pnH₂ = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH₂ = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis, infrared, Raman, UV-Vis and ¹H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS₄]²⁻ tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting of the W–S vibrations, which can be attributed to the distortion of the [WS₄]²⁻ tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than 0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric stretching vibration of the W–S bond.     

Activated Nitriles with Ammonium Benzyldithiocarbamate,Synthesis of Thietane Derivatives

4-Aryl-2-iminothietane-3-carbonitriles 3 were obtained in a moderate yield via the reaction of substituted arylidene malononitriles with ammonium benzyldithio-carbamate. The reaction of 3a with hydrazine hydrate, ethyl carbazate, phenylisothiocyanate, and carbon disulphide have been investigated.     

Synthesis,Characterization, Crystal Structure,and Properties of a Mercury(Ii) Complex Containing Dmit Ligand and N,N’-Ethylidenedipyridium Cation

A new mercury(II) complex containing dmit ligand and biquaternary ammonium cation, DPyE[Hg(dmit)₂] (1) (DPyE²⁺ = N,N’-ethylidenedipyridinium, dmit = 1,3-dithiol-2-thione-4,5-dithiolate), was synthesized and fully characterized by elemental analysis, IR, ¹H-NMR, UV–Vis, TG, single crystal X-ray diffraction, and powder X-ray diffraction. Moreover, the electrochemical properties and conductivities of complex 1 were studied by cyclic voltammetry and four-probe AC technique, respectively. Complex 1 crystallizes in the monoclinic space group P 2₁/n with a = 8.1815(2) Å, b = 12.8701(5) Å, c = 23.2681(7) Å, β = 90.922(3)°, Z = 4, V = 2449.75(14) ų, D_c = 2.114 g·cm^–3. The crystal structure shows that the dihedral angle of two dmit ligands of [Hg(dmit)₂]^2– anion is closed to vertical, which results in the formation of a distorted HgS₄ tetrahedral geometry. The S···S short contacts assemble [Hg(dmit)₂]^2– anions into 1D, 2D, and 3D supramolecular network. The DPyE²⁺ cations are located in the caves, providing additional stabilization to crystal packing via C–H···S hydrogen bonds to [Hg(dmit)₂]^2– anions. The crystal packing of 1 is characterized by face-to-face π-π contacts between DPyE²⁺ cations and [Hg(dmit)₂]^2– anions, which result in two orthogonally oriented and mixed stacking columns. These stacking columns interweave into a 2D network, which is further connected to a 3D network via interplanar S···S contacts. In addition, the temperature-dependent conductivity in the range of 50–300 K reveals semi-conducting properties of complex 1, and a room temperature conductivity of 1.53 × 10^–3 S·cm^–1 is observed.     

Antibacterial membranes based on chitosan and quaternary ammonium salts modified nanocrystalline cellulose

Etherification of nanocrystalline cellulose (NCC) with three kinds of quaternary ammonium salts epoxypropyltrimethylammonium chloride, N,N‐dimethyl‐N‐dodecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMDEPAC), and N,N‐dimethyl‐N‐octadecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMOEPAC) was successfully performed via a nucleophilic addition reaction. The synthesized DMDEPAC and DMOEPAC were characterized by nuclear magnetic resonance. The modified NCC particles, NCC epoxypropyltrimethylammonium chloride, NCC‐DMDEPAC, and NCC‐DMOEPAC, were characterized by energy dispersive spectrometer. Nanocomposite films based on chitosan (CS) containing quaternary ammonium salts modified NCC were prepared with nanoparticle loadings of 5.0, 7.5, and 10.0%, respectively. The effect of nanoparticle content on the tensile strength of composite films was studied. The results indicated that the films with 5.0% nanoparticle loading exhibited the biggest increase in tensile strength. Surface morphology, smoothness, and antibacterial properties of composite films containing 5% modified NCC were also studied. CS/NCC‐DMDEPAC‐5.0 and CS/NCC‐DMOEPAC‐5.0 displayed excellent biocidal abilities against both Gram‐positive Staphylococcus aureus (ATCC 6538) and Gram‐negative Escherichia coli O157:H7 (ATCC 43895). The bio‐based nanocomposite films with increased mechanical strength and excellent antibacterial properties show great potential as food packaging materials. Copyright © 2017 John Wiley & Sons, Ltd.     

Synthesis and antimicrobial evaluation of some new N-pyridinium,quinolinium, and isoquinolinium sulfonate derivatives

1,3-propane- and/or 1,4-butane sultone (sultones are internal esters of hydroxyl sulfonic acid) are used as a chemical intermediate to introduce sulfopropyl and/or sulfobutyl groups into heterocyclic molecules and to confer water solubility and anionic character to the molecules. Therefore, the synthesis of three novel functionalized N-sulfonates is described. These sulfonates contain pyridyl (2a–f), quinolyl (4a–m), and isoquinolyl (6a,b) functional groups with potential biological activity. The synthesized quaternary ammonium salts, 3-(2 or 4-arylpyridinium-1-yl)propane or butane-1-sulfonate (2a–f), 3-(alkylquinolinium-1-yl)propane or butane-1-sulfonate (4a–m), and 3-(alkylisoquinolinium-1-yl)propane or butane-1-sulfonate (6a,b), were screened for their antimicrobial and antifungal activities. Among all tested compounds, it was found that compound 4-(4-carboxypyridinium-1-yl)butane-1-sulfonate (2f) showed high activity against Gram-positive bacteria, Gram-negative bacteria, and tested fungi. Most of the compounds showed a moderate degree of antimicrobial activity. The structures of these compounds were confirmed on the basis of their analytical and spectral data (infrared, ¹H-NMR and ¹³C-NMR spectroscopy, and mass spectral data).     

The antibacterial finish of cotton via sols containing quaternary ammonium salts

The sols containing quaternary ammonium salts were prepared via sol-gel process. The effects of the molar rate of HCl, H₂O and EtOH to TEOS on the sol viscosity were investigated in detail. Cetyltrimethylammonium bromide (CTAB), Octadecyl dimethyl benzyl ammonium chloride (DC) and Ethylene-Bis (Octadecyl trimethyl ammonium chloride) [E-Bis(OTAC)]were added in the sols and applied to cotton samples by treated. The antibacterial activities of the samples were assessed against both Escherichia coli and Staphylococcus aureus bacteria. The samples treated by E-Bis(OTAC) sol exhibited the satisfactory antibacterial activity that resulted from the more microorganism adsorption and hydrophobicity. The antibacterial activities were still excellent after 10 times washings comparison with the control samples.     

微波辐射下5-取代-2-硫代海因衍生物的合成

微波辐射下, 由硫氰酸铵与α-氨基酸通过两步反应合成了11种5-取代-2-硫代海因衍生物, 并用¹H NMR, IR和元素分析确证了中间产物和终产物的结构. 对比常规加热方法, 微波辐射具有反应时间短(4 min), 每步反应产率高(85%～93%)的优点. 同时对合成化合物2h的反应历程进行了讨论.