Chloride Derivatives Research Articles

Crystallization and preliminary X-ray crystallographic analysis of the variable domain of Scl2.3, a streptococcal collagen-like protein from invasive M3-type Streptococcus pyogenes.

Streptococcal collagen-like proteins (Scls) are widely expressed by the well recognized human pathogen Streptococcus pyogenes. These surface proteins contain a signature central collagen-like region and an amino-terminal globular domain, termed the variable domain, which is protruded away from the cell surface by the collagen-like domain. Despite their recognized importance in bacterial pathogenicity, no structural information is presently available on proteins of the Scl class. The variable domain of Scl2 from invasive M3-type S.pyogenes has successfully been crystallized using vapour-diffusion methods. The crystals diffracted to 1.5 Å resolution and belonged to space group H32, with unit-cell parameters a = 44.23, b = 44.23, c = 227.83 Å. The crystal structure was solved by single-wavelength anomalous dispersion using anomalous signal from a europium chloride derivative.|

A Noncatalytic Approach to Hetaryl‐Annulated 1,2,4‐Thiadiazine‐1,1‐dioxides

A set of synthetic procedures was developed to yield functionalized pyrido‐, pyrimido‐, and thiazo‐annulated thiadiazine‐1,1‐dioxides on a preparative scale. In all cases the thiadiazine‐1,1‐dioxide ring closure was carried out through a reaction of hetaryl‐sulfonyl chlorides with amidines under mild noncatalytic conditions. In the case of 2‐chloropyridine‐3‐sulfonyl chloride derivatives and 2,4‐dichlorothiazole‐5‐sulfonyl chloride open‐chain sulfonylated amidine intermediates were isolated and then subjected to the cyclization step. The reaction with 2,4‐dichloropyrimidine‐5‐sulfonyl chloride gave rise to the corresponding thiadiazine‐1,1‐dioxides in one‐pot. Similarly, a reaction of 2‐chloropyridine‐3‐sulfonamide with lactime ethers proceeded in one‐pot readily giving the corresponding thiadiazine‐1,1‐dioxides. Remaining chlorine atoms on the prepared hetaryl‐annulated benzothiadiazine‐1,1‐dioxides readily undergo aromatic nucleophilic displacement reactions serving thus as additional variation points for the design of biologically potent compounds.

Molecular modelling and spectral investigation of some triphenyltetrazolium chloride derivatives

AbstractThe molecular parameters of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) and some compounds based on triphenylformazans (TPFs) — resulting from the enzymatic transformation of TTC, were subjected to comparative investigation on the basis of semi-empirical quantum-chemical simulations, revealing some changes in dipole moment and polarisability in the TPFs in comparison with TTC. Chemical shift due to substituents was discussed using electronic absorption bands in the UV-VIS range recorded for diluted solutions in various solvents as well as the absorption spectra recorded in the infrared range for KBr dispersions. The correlation of the spectral shift of the electronic absorption bands with a specific function on the solvent refractive index, as recommended by theoretical studies focused on solute-solvent interactions, revealed the major role played by dispersive and induction forces. For several solvents, a different behaviour could be assigned to specific interactions overlapping with universal solute-solvent interactions.

Polyampholyte/Surfactant Complexes at the Water–Air Interface: A Surface Tension Study

The present paper is related to interactions between strongly alternating polyampholytes, i.e., copolymers of N,N'-diallyl-N,N'-dimethylammonium chloride and maleamic acid derivatives, varying in hydrophobicity and excess charges and the oppositely charged anionic surfactant sodium dodecyl sulfate (SDS). Surface tension measurements have revealed a complex behavior with the formation of polyampholyte-SDS complexes at water-air interfaces which depends on both the hydrophobic character of the polyampholyte and electrostatic attractive forces between the polyampholyte and the anionic surfactant in dependence on pH. Hereby, maleamic acid copolymers with additional carboxylic groups in the phenylic side chain show a significant lower surface tension at the critical association concentration (CAC) due to the formation of surface-active SDS complexes and multicomplexes. In the presence of only one carboxylic group in the p-position the CAC can be strongly shifted by varying the pH due to repulsive electrostatic interactions.

Bis(4-picoline-κN)gold(I) dibromidoaurate(I) and bis(4-picoline-κN)gold(I) dichloridoaurate(I): space-group ambiguity?

Bis(4-picoline-κN)gold(I) dibromidoaurate(I), [Au(C6H7N)2][AuBr2], (I), crystallizes in the monoclinic space group P21/n, with two half cations and one general anion in the asymmetric unit. The cations, located on centres of inversion, assemble to form chains parallel to the a axis, but there are no significant contacts between the cations. Cohesion is provided by flanking anions, which are connected to the cations by short Au···Au contacts and C-H···Br hydrogen bonds, and to each other by Br···Br contacts. The corresponding chloride derivative, [Au(C6H7N)2][AuCl2], (II), is isotypic. A previous structure determination of (II), reported in the space group P1 with very similar axis lengths to those of (I) [Lin et al. (2008). Inorg. Chem. 47, 2543-2551], might be identical to the structure presented here, except that its γ angle of 88.79 (7)° seems to rule out a monoclinic cell. No phase transformation of (II) could be detected on the basis of data sets recorded at 100, 200 and 295 K.

Coordination Complexes of Bismuth Triflates with Tetrahydrofuran and Diphosphine Ligands

The reaction of CH3OSO2CF3 (MeOTf) with BiBr3 in tetrahydrofuran (THF) yields (THF)2BiBr2(OTf) (1), which is converted to (dmpe)BiBr2(OTf) (2Br) upon displacement of the THF ligands with bis(dimethylphosphino)ethane (dmpe). The chloride derivatives (dmpe)BiCl2(OTf) (2Cl) and (dmpe)BiCl(OTf)2 (3) are obtained from the reaction of BiCl3 and dmpe with 1 and 2 equiv of Me3SiOSO2CF3 (TMSOTf), respectively. The complexes readily decompose in solution to give elemental bismuth and a mixture of products. The solid-state structures reveal dimeric units bridged by both triflate O-S-O interactions and weak Bi-X-Bi interactions (X = Cl, Br). Comparison of the solid-state structures illustrates that both cis and trans configurations of halides are possible in complexes of the form L2BiX2(OTf), depending upon the denticity of the ligand. The experimentally observed configurations are consistent with minima calculated at the MP2 level for the triflate-free cations in the gas phase. Examination of the MP2-calculated electronic structure of 3 reveals the presence of low-lying π-type orbitals that may result in Z-type ligand activity. However, the attempted coordination of 3 with the electron-rich metal center in K2PdCl4, via metal-to-ligand back-donation, leads instead to halide abstraction, giving [(dmpe)2Pd][(CH3CN)2Bi2Cl6(OTf)2] (8). The anion in 8 consists of two octahedral bismuth environments bridged along one edge by two triflate anions. The results illustrate new coordination chemistry for bismuth.

Synthesis and characterization of ester and amide derivatives of titanium(IV) carboxymethylphosphonate

Abstract A set of layered ester and amide derivatives of titanium(IV) carboxymethylphosphonate was prepared by solvothermal treatment of amorphous titanium(IV) carboxymethylphosphonate with corresponding 1-alkanols, 1,ω-alkanediols, 1-aminoalkanes, 1,ω-diaminoalkanes and 1,ω-amino alcohols and characterized by powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Whereas alkyl chains with one functional group form bilayers tilted to the layers, 1,ω-diaminoalkanes and most of 1,ω-alkanediols form bridges connecting the adjacent layers. In the case of amino alcohols, the alkyl chains form bilayer and either hydroxyl or amino group is used for bonding. This simple method for the synthesis of ester and amide derivatives does not require preparation of acid chloride derivative as a precursor or pre-intercalation with alkylamines and can be used also for the preparation of ester and amide derivatives of titanium carboxyethylphosphonate and zirconium carboxymethylphosphonate.

Synthesis of C- and O-prenylated tetrahydroxystilbenes and O-prenylated cinnamates and their action towards cancer cells

Synthesis of the naturally occurred C- and O-prenylated tetrahydroxystilbenes and O-prenylated cinnamates was carried out by decarbonylative Heck reaction and selenium dioxide catalysed oxidation, respectively. In the decarbonylative Heck synthetic route, fusion of benzoyl chloride and styrene derivatives was catalysed by an N-heterocyclic carbene system generated in situ by palladium acetate and 1,3-bis(2,6-diisopropylphenyl)imidazolinium chloride to form a E-tetrahydroxystilbene derivative. Formation of allyl ether was subsequently carried out by reaction of the deprotected OH in the A phenyl ring of the stilbene with 3,3-dimethylallyl bromide and a base (sodium hydride) to form O-prenylated tetrahydroxystilbene derivatives. [1,5]-Rearrangement of the isoprenyl unit from O- to C-position in the A ring was carried out at elevated temperature in the presence of magnesium silicate (Florisil) to form the corresponding C-prenylated tetrahydroxystilbene. Formation of O-prenylated cinnamate was first carried out by base catalysed allyl ether formation between 3,3-dimethylallyl bromide and hydroxycinnamic acid methyl ester. The methyl group of the isoprenyl unit was subsequently oxidized using selenium dioxide to form a terminal hydroxyl group. The prenylated tetrahydroxystilbenes and cinnamate synthesized in this study were novel derivatives of piceatannol and methyl 4-(3′-methylbut-2′-enyloxy)cinnamate isolated from propolis in Kangaroo Island, South Australia. The synthetic compounds were tested against K562 cancer cells and potent growth inhibitory activity was observed for E-1-[5-hydroxy-3-methoxy-2-(3-methyl-2-butenyl)phenyl]-2-[4-hydroxy-3-methoxyphenyl]ethene, IC50 = 0.10 μM.

Modification of chitosan derivatives of environmental and biological interest: A green chemistry approach

Chitosan is a non-toxic polyaminosaccharide that is available in a variety of useful forms, and its chemical and biological properties make it a very attractive biomaterial that could be used in a wide variety of medicinal applications. This work focuses on the preparation of different chitosan derivatives by treatment with ethyl cellulose, cellulose triacetate and different carbohydrates in both neutral and slightly acidic media. It also addresses modification with glycidyltrimethyl ammonium chloride, phthalic anhydride and succinic acid derivatives. The obtained derivatives were crosslinked with glutaraldehyde. Thermo-gravimetric (TGA) and FT-IR spectroscopic analyses and electron scanning microscopy (SEM) were used to characterize the obtained products and demonstrate the success of the chitosan-modification process. The obtained products were tested for their ability to uptake transition metal ions from aqueous solutions, and their ion-uptake efficiency was determined with the aid of the ICP-AES technique. The bioactivity of some selected products was tested to study the effect of their concentrations on selected microorganisms. Burkholderia cepaci, Aspergillus niger, and Candida albicans were selected as representative examples of bacteria, yeasts and fungi, respectively.

One pot conversion of carbohydrates alcohol into chloride via benzotriazole sulfonate

A one pot method for chloro-dehydroxylation of carbohydrates alcohol including sterically and electrically hindered ones in excellent yield was developed. The benzotriazole-1-sulfonate proposed to play a crucial role in the reaction medium, which undergoes substitution by chloride ion in the reaction medium to give only desired chloride derivative without the formation of side product. The optimized methodology can be used in the synthesis of number of biologically active compounds or chiral synthones.

<b>Reactivity of the Active Chlorine of Cyanuric Chloride Immobilized on Cotton Fibers</b>

Cyanuric chloride-immobilized cotton fibers were prepared by treatment with cyanuric chloride in benzene followed by immersion with alkali. Surface characterization of the surface-modified cotton fiber was carried out by means of ATR-FTIR spectroscopy. Reactivity of active chlorine in cyanuric chloride moiety immobilized on the cotton fibers was evaluated by reaction with the amino group-containing compounds in both aqueous and non-aqueous systems. An acidic dye to the water-soluble amino group-containing compound and the alkylamines to water-insoluble amino-containing compound were used. In the aqueous system, it was found that substitution reaction of active chlorines with an amine group and the active chlorine proceeded remarkably under acidic conditions rather than under alkaline conditions. It was also suggested that two of chlorine atoms of cyanuric chloride immobilized on fibers did not exhibit stepwise sequential reaction which is common for low-molecular cyanuric chloride derivatives. Furthermore, after the reaction under acidic conditions, activity of the unreacted active chlorine is remained.This indicated that the chlorines were not consumed by a reaction with water. On the other hand, it was found that if the surface-modified fabrics were treated with different water-insoluble alkylamines, their fabrics demonstrated a good water repellency. This indicates that the active chlorine reacts with the amino group easily even in benzene. The degree of water repellency can be controlled by the alkylamine concentration in the non-aqueous media. Taking into consideration these results, it was concluded that the cotton fibers which have been treated with cyanuric chloride may be reacted sequentially with wide variety of water-soluble and/or water-insoluble amino group-containing compounds.

Application of SBA-Pr-SO3H in the synthesis of benzoxazole derivatives

Propylsulfonic acid functionalized SBA-15 (SBA-Pr-SO 3 H) catalyzed the synthesis of 2-aryl benzoxazoles from 2-aminophenol and benzoyl chloride derivatives in good yields under reflux condition in acetic acid. In solvent free condition, hydroxybenzanilide derivatives were obtained.

Cyanide selective electrodes based on a porphyrinatoiron(III) chloride derivative

Tetrakis-4-chlorophenylporpherinatoiron(III) chloride (FeT(4-ClP)PCl) was used as an ionophore for the construction of two kinds of cyanide ion selective electrodes, i.e., Polyvinilchloride (PVC) membrane and membrane coated graphite electrodes. Different membrane constituents were optimized for the electrodes. Membranes with 65.5% o-nitrophenyl octyl ether (o-NPOE), 32.7% PVC, 0.8% ionophore, and 1.0 cetyltetramethylammonium bromide (CTAB) gave the best Nernstian responses to cyanide ion activity in the concentration range of 6.3×10−7–1.2×10−2M. A polyaniline thin film was coated over the graphite electrodes prior to membrane coating; this modification was found suitable for both smooth functioning and fast response time of the graphite electrodes. Response time of the electrodes was found to be about 5s. Finally, a broader concentration range was found for coated graphite electrodes with respect to the PVC membrane electrodes.

Synthesis of a novel flame retardant containing phosphorus-nitrogen and its comparison for cotton fabric

A new charring agent, a derivative of cyanuric chloride, mono-substituted, dimethyl (4,6-dichloro-1,3,5-triazin-2- yloxy)methylphosphonate (CN), was synthesized in good yield and characterized. Its flame retardant and thermogravimetric properties were compared to those of the di-substituted compound, tetramethyl (6-chloro-1,3,5-triazine-2,4-diyl)bis(oxy)bis (methylene)diphosphonate (CN-1), which was prepared in previous work. All untreated fabric showed limiting oxygen index (LOI) values of about 18 vol% oxygen in nitrogen. Fabrics treated with CN at 5-21 wt% add-ons had high LOI values of 30- 40 vol%, while fabrics treated with CN-1 at 5-19 wt% add-ons had low to high LOI value of 20-36 vol%. In 45 o angle flammability tests, all treated fabrics with CN and CN-1 were passed and some fabrics were not igniting at all. Thermal degradation revealed that onset of degradation and the char yield of CN compound is higher than that of CN-1. Treated fabric with CN, 21 wt% add-on, had an onset of degradation of 240 oC, while fabric treated with CN-1, 19 wt% add-on displayed an onset of degradation of 230 o C. Despite the differences in onset temperature, the two samples provided almost the same char yield at 600 o C, 35 and 36 %. With Fourier transform infrared (FTIR), samples of treated/unburned and treated/burned of CN and CN-1 showed the same functional groups and revealed the disappearance of triazine group and P-O-methyl after burning. Additionally, scanning electron microscopy (SEM) showed that both CN and CN-1 acted as flame retardants by the same mechanism and characterized the surface morphology of the flame retardant treated twill fabrics.

Synthesis of some novel benzimidazole derivatives and it's biological evaluation

A series of new benzimidazole derivatives have been synthesized by simple condensation reaction between benzimidazole derivatives and phenyl sulphonyl chloride derivatives. All these compounds were characterized by FT-IR, 1 H NMR, MS and elemental analysis. These compounds were screened for antibacterial and antioxidant activities, respectively. The antibacterial activities were compared with the standard drug such as chlorophenicol and antioxidant activities were compared with the ascorbic acid.

ChemInform Abstract: Intramolecular [2 + 2] Cycloaddition of Homoallylketenes to Bicyclo[2.1.1]hexan‐5‐ones.

Intramolecular [2+2] cycloaddition of γ,δ-unsaturated ketenes derived from hex-5-enoyl chloride derivatives gave bicyclo[2.1.1]hexan-5-ones with complete regioselectivity.

Nitrate removal from water by quaternized pine bark using choline based ionic liquid analogue

AbstractBACKGROUND: The objective of this study was to quaternize pine bark (PB) wood residues using green chemistry and to use the quaternized PB to remove nitrate (NO3−) from water. The quaternization process was achieved by reacting the wood residues with an ionic liquid analogue comprised of a choline chloride derivative and urea. Batch adsorption tests were used to delineate the NO3− uptake by the modified pine bark (MPB). Fourier Transform Infrared Spectroscopy (FTIR) analysis and Zeta potential measurements were used to characterize the changes at the surface of the PB due to quaternization and NO3− uptake.RESULTS: The MPB has a maximum NO3− uptake capacity of 2.91 mmol g−1. The NO3− uptake kinetics indicated that diffusion through the boundary layer of the MPB was the rate limiting step. The Langmuir adsorption model provided a better fit for the uptake data than the Freundlich model, indicating monolayer adsorption. The uptake process was found dependent on concentration, pH and ionic strength, and was also spontaneous and exothermic. The desorption–regeneration experimental results indicated a 95% efficiency after five consecutive regeneration cycles.CONCLUSIONS: The quaternization technique was found very effective for developing effective and green anion exchange resins to remove NO3− from water. © 2012 Society of Chemical Industry

Facile Synthesis of Dendritic Hydroxyl‐terminated Cyanuric Chloride Derivatives and Their Properties

AbstractNovel dendritic compounds G1.5(OH)4 and G1.5(OH)8 with peripheral hydroxyl were synthesized under mild conditions from cyanuric chloride, ethylene diamine, ethanolamine and diethanolamine. The products could be separated and purified through dispersion and precipitation in organic solvents with good yields (over 93.0%) and high purity (above 98.0%, HPLC). The structures of the products were characterized by IR, MS, 1 H NMR and elementary analysis. G1.5(OH)4 and G1.5(OH)8 could be dissolved in polar solvents such as methanol, water and dimethylsulfoxide. TGA analysis showed that G1.5(OH)4 and G1.5(OH)8 had good thermo stability. The aqueous solutions of G1.5(OH)4 and G1.5(OH)8 exhibited low surface tension.

Palladium-Catalyzed Benzylic Cross-Couplings of Pyridine N-Oxides

Palladium-catalyzed C-H couplings (C SP ³ -C SP ² ) of pyridine N-oxides with benzyl chloride derivatives is reported. It provides a novel and easy process for the synthesis of 2-benzylpyridine derivatives through benzylic cross-couplings of pyridine N-oxides.

ChemInform Abstract: Various Entries to Vinyl Chloride Derivatives and Their Applications in Total Synthesis of Natural Products

AbstractReview: ca. 50 refs.