Iodide Derivatives Research Articles

A new synthetic access to bicyclic iminosugars—derivatives of polyhydroxy decahydropyrido[1,2-a]azepine

An efficient and highly stereoselective synthesis of bicyclic iminosugars, derivatives of polyhydroxylated decahydropyrido[1,2-a]azepine, was developed. Starting from a two-component coupling reaction, through nitrone formation and a 1,3 dipolar cycloaddition, an azabicyclic intermediate was obtained. In subsequent reaction sequences, the azabicyclic intermediate was converted into the corresponding epoxide derivative. The N–O bond reductive cleavage, followed by an intramolecular 7-endo-tet cyclization, was the crucial step leading to seven-membered ring closure. Additionally, an alternative synthetic pathway using the bicyclic iodide derivative was explored. The inhibitory activity of the synthesized decahydropyrido[1,2-a]azepines against selected glycosidases was examined.

Self-Assembled Cyclophane-Type Copper(I) Complexes of 2,4,6-Tris(diphenylphosphino)-1,3,5-triazine and Their Catalytic Application.

The triazine-based trisphosphine, 2,4,6-tris(diphenylphosphino)-1,3,5-triazine (1) was prepared in improved yield by reacting cyanuric chloride with 3 equiv of trimethylsilyldiphenylphosphine. The solid-state structure of 1 showed short intermolecular P···P contacts of 3.362 Å, which is significantly shorter than the sum of the van der Waals radii of phosphorus atoms (3.6 Å). The reaction of 2,4,6-tris(diphenylphosphino)-1,3,5-triazine (1) with copper(I) salts in a 2:3 molar ratio yielded various cyclophane-type complexes in quantitative yield. The solid-state structures of these clusters have been found to depend on the size of the halide ions, the solvent employed, and the reaction conditions. Copper(I) chloride formed a monomeric metallocyclophane, whereas copper(I) bromide and copper(I) iodide derivatives preferred dimeric and 1D-polymeric structures, respectively. The tricationic complexes derived from Cu(I) ion and 2,4,6-tris(diphenylphosphino)-1,3,5-triazine also adopted monomeric metallocyclophane structures. These complexes have been employed in the A(3) coupling reaction under microwave irradiation. The copper(I) iodide derivative showed excellent catalytic efficiency.

Identification of dyes in toned and tinted XX century cinematographic films by surface enhanced Raman spectroscopy

In this paper some colored frames coming from the very popular cinematographic film Sardinian Drummer Boy, dating back to the beginning of the XX century, were analyzed. The presence in the emulsion of silver nanoparticles (AgNPs), which are formed thanks to the impression–development mechanism, confers to the cinematographic film the characteristic of being an efficient Surface Enhancement Raman Spectroscopy (SERS) substrate. This peculiarity makes it possible to investigate, in a non-invasive way, the nature of the film components, such as the dyes used for the coloring process. In particular, Raman analyses allowed the unambiguous identification of the dyes used in tinted frames, i.e. tartrazine and safranin, in which the colorant is absorbed by the gelatin, and in toned frames, i.e. Rhodamine B, where the dye is fixed thanks to the formation of an insoluble species with AgI obtained by conversion of metallic silver. This second case is of particular interest to evaluate the possibility to identify the dye even when it is present as a silver iodide derivative. For this purpose an AgI-colorant derivative has been prepared and its SERS spectrum compared with that obtained on the film sheet. Copyright © 2015 John Wiley & Sons, Ltd.

Light-Induced Increase of Electron Diffusion Length in a p-n Junction Type CH3NH3PbBr3 Perovskite Solar Cell.

High band gap, high open-circuit voltage solar cells with methylammonium lead tribromide (MAPbBr3) perovskite absorbers are of interest for spectral splitting and photoelectrochemical applications, because of their good performance and ease of processing. The physical origin of high performance in these and similar perovskite-based devices remains only partially understood. Using cross-sectional electron-beam-induced current (EBIC) measurements, we find an increase in carrier diffusion length in MAPbBr3(Cl)-based solar cells upon low intensity (a few percent of 1 sun intensity) blue laser illumination. Comparing dark and illuminated conditions, the minority carrier (electron) diffusion length increases about 3.5 times from Ln = 100 ± 50 nm to 360 ± 22 nm. The EBIC cross section profile indicates a p-n structure between the n-FTO/TiO2 and p-perovskite, rather than the p-i-n structure, reported for the iodide derivative. On the basis of the variation in space-charge region width with varying bias, measured by EBIC and capacitance-voltage measurements, we estimate the net-doping concentration in MAPbBr3(Cl) to be 3-6 × 10(17) cm(-3).

ChemInform Abstract: Cyclization of η3‐Benzylpalladium Intermediates Derived from Carbene Insertion.

Abstract1‐Arylindanes and 1‐aryltetralines (XI) are prepared by palladium catalyzed carbenylative cyclization reaction of aryl iodide derivatives and N‐tosylhydrazines.

Enantiospecific Synthesis of (-)-Cuspareine and (-)-Galipinine

An enantiospecific route to the synthesis of tetrahydroquinoline alkaloids (–)-cuspareine and (–)-galipinine is reported. Coupling of an iodide derivative of D-serine with aromatic dithianes and Pd-catalyzed intramolecular C–N coupling are the key steps in the synthesis.

Synthesis and structural characterization of tris(2-mercapto-1-methylbenzimidazolyl)hydroborato cadmium halide complexes, {[Tm(MeBenz)]Cd(μ-Cl)}2 and [Tm(MeBenz)]CdI: a rare example of cadmium in a trigonal bipyramidal sulfur-rich coordination environment.

The tris(2-mercapto-1-methylbenzimidazolyl)hydroborato cadmium complexes, {[Tm(MeBenz)]Cd(μ-Cl)}2 and [Tm(MeBenz)]CdI, have been synthesized via the reactions of [Tm(MeBenz)]K with CdCl2 and CdI2, respectively. While X-ray diffraction studies demonstrate that the iodide derivative, [Tm(MeBenz)]CdI, is a monomer, the chloride derivative, {[Tm(MeBenz)]Cd(μ-Cl)}2, exists as a dimer, which is unprecedented for Group 12 [Tm(R)]MX (X = Cl, Br, I) compounds. Furthermore, the cadmium centers of {[Tm(MeBenz)]Cd(μ-Cl)}2 are trigonal bipyramidal, which is an uncommon motif for cadmium complexes with a [S3Cl2] coordination sphere.

High Voltage AC/AC Capacitors Using the Carbon/Iodine Interface in Ionic Liquid Electrolyte

Lately we have demonstrated that huge pseudo-capacitive contributions can be originated from the electrolyte when using high surface area activated carbon electrodes, for example by using iodide based solutions in water [1]. Although the use of such concept allows very high capacitance values to be reached, the energy of the AC/AC capacitors based on these electrolytes is limited by the relatively low value of voltage inherent to use of water. Therefore, in this work, we have investigated the performance of the carbon/iodine interface in ionic liquid electrolytes, both protic (PIL) and aprotic (AIL).The PILs selected were triethylammonium bis(tetrafluoromethylsulfonyl)imide [Et3NH]-[TFSI] and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide [Emim]-[FSI]. Organic iodides - triethylammonium iodide [Et3NH]-[I] and tetraethylammonium iodide [Et4N]-[I] at a concentration of 0.25 mol·L-1 and inorganic iodides (LiI and KI) at a concentration of 0.2 mol·L-1 were introduced in the ionic liquid. The electrochemical experiments as cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy were conducted using a two-electrode cell construction. In some experiments, a silver wire was added as pseudo-reference to monitor the potential of individual electrodes. Activated carbon (AC) activated by KOH (4:1) with high microporosity ( SBET = 2180 m2·g-1, Vmicro = 0.96 cm3·g-1, L0 = 1.55 nm) was used as working and counter electrode. Glass microfiber paper (Whatman) was utilized as separator.Galvanostatic (0.2 A·g-1) cycling up to 1.8 V in two-electrode cell with reference electrode (Figure 1B) demonstrates a remarkable increase of capacitance when KI is added to [Et3NH]-[TFSI], from 122 to 184 F·g-1. The voltammograms of figure 1A show clearly that the increase of capacitance is caused by the positive electrode where faradaic processes occur. The capacitance values of the positive electrode for 0.25 mol·L-1 [Et3NH]-[I] and 0.2 mol·L-1 LiI dissolved in [Et3NH]-[TFSI] reached 199 and 238 F·g-1 , respectively; for the negative electrode the capacitance reached 163 and 121 F·g-1 , respectively. The addition of 0.2 mol·L-1 inorganic iodide to aprotic IL also enhanced the capacitance from 116 F·g-1 for the pure AIL to 129 and 153 F·g-1for the KI and LiI solutions, respectively. Regardless of the different type of iodide derivatives dissolved in IL medium, faradaic processes occur at the positive electrode greatly increasing the capacitance of the whole capacitor system. However, iodide solutions in PILs seem to be more effective than the AILs ones. Acknowledgements:The Foundation for Polish Science is acknowledged for supporting the ECOLCAP Project realized within the WELCOME Program, co-financed from European Union Regional Development Fund.

Photobehaviour of methyl-pyridinium and quinolinium iodide derivatives, free and complexed with DNA. A case of bisintercalation.

Excited state dynamics of four azinium salts were studied in buffered water and in the presence of salmon testes DNA. Complexation with DNA changes the photobehaviour of the free ligands lowering the photoreactivity and emission in favor of internal conversion. The interaction of these four dyes with DNA was studied with different techniques with the aim to establish the affinity and the type of binding between the ligands and DNA. The results from spectrophotometric and fluorimetric titrations provided evidence of a strong interaction between the azinium salts and the polynucleotide, with a binding constant of about 10(6) M(-1), making them interesting for therapeutical applications. Dichroic measurements allowed us to determine the possible modes of binding for each complex. Short living excited states of the free dyes were detected and characterized by ultrafast absorption spectroscopy. A further decrease of transient lifetimes was observed upon interaction with DNA. The bicationic pyridinium iodide was found to act as a bisintercalative agent, potentially increasing the cytotoxicity with low dose and less collateral effects.

ChemInform Abstract: Enantioselective Total Synthesis of (‐)‐Minovincine in Nine Chemical Steps: An Approach to Ketone Activation in Cascade Catalysis.

ChemInform Abstract: Enantioselective Total Synthesis of (‐)‐Minovincine in Nine Chemical Steps: An Approach to Ketone Activation in Cascade Catalysis.

OneF-Octyl versus TwoF-Butyl Chains in Surfactant Aggregation Behavior

An easy synthetic procedure in two or three steps from perfluoroalkylethyl iodide derivatives led to six novel fluorinated carboxylates monomeric and gemini surfactants with one or two hydrophobic tails, respectively: RF(C2H4)CH(CO2(-))2,2Na(+) and [RF(C2H4)]2C(CO2(-)),Na(+), where RF = C4F9, C6F13, and C8F17. These anionic surfactants exhibited very low surface tension from 15 to 33 mN/m as well as low critical micelle concentration until 1.3 × 10(-4) mol/L. Furthermore, the surface properties of the gemini compound with two short fluoroalkyl chains (RF = C4F9) were found to be almost equal to those of the monomeric surfactant with one long fluoroalkyl chain (RF = C8F17), which could provide an interesting alternative to the bioaccumulative long-chain perfluorinated surfactant.

Diastereoselectiveortho-Metalation of a Chiral Ferrocenylphosphonic Diamide and Its Organotin Derivatives

The syntheses of the enantiopure ferrocenylphosphonic diamide (3aR,7aR)-2-ferrocenyl-3a,4,5,6,7,7a-octahydro-1,3-dimethyl-1,3,2-benzodiazaphosphole 2-oxide ((R,R)-FcP(O)(DMCDA), (R,R)-1) and its enantiomer (S,S)-FcP(O)(DMCDA) ((S,S)-1) are reported. Their ortho lithiation and subsequent treatment with Ph3SnCl selectively provided the corresponding tetraorganotin derivatives FcP(O)(DMCDA)SnPh3 ((R,R,RP)-2 and (S,S,SP)-2) in a diastereoselective ratio of 88:12. The absolute configuration of the major diastereomer was confirmed by single-crystal X-ray diffraction analysis. DFT calculations revealed that kinetic effects of the lithiation step cause the high diastereoselectivity of the formation of (R,R,RP)-2. Further functionalization of (R,R,RP)-2 with elemental iodine gave the enantiopure organotin iodide derivatives FcP(O)(DMCDA)SnInPh3–n ((R,R,RP)-3:, n = 1; (R,R,RP)-4, n = 2, (R,R,RP)-5, n = 3). The triorganotin fluoride FcP(O)(DMCDA)SnFPh2 ((R,R,RP)-6) was obtained by the reaction of (R,R,RP)-3 in dichloromethane with aqueous KF solution. The reaction of the compound (R,R,RP)-3 with silver triflate gave the R,R,RP-configurated triorganotin triflate FcP(O)(DMCDA)SnPh2(OTf) (7), which exists as a contact ion pair in the solid state and shows dynamic behavior in solution. The reaction of 7 with Ph3PO afforded the corresponding organotin salt [FcP(O)(DMCDA)SnPh2(OPPh3)][OTf] ((R,R,RP)-8).

ChemInform Abstract: Synthesis of γ‐Oxo γ‐Aryl and γ‐Aryl α‐Amino Acids from Aromatic Aldehydes and Serine.

γ-Oxo α-amino acids and γ-aryl α-amino acids are compounds with very interesting biological properties and are active components of many drug molecules. Oxo amino acids are also used as synthetic precursors for a number of unnatural amino acids and amino alcohols. We report a very efficient synthesis of such compounds through the coupling of aromatic dithianes, prepared from aromatic aldehydes and an iodide derivative of serine. The dithiane groups in compounds thus obtained can be either hydrolyzed or reduced to generate 4-oxo-4-aryl or 4-aryl 2-amino butanol derivatives, respectively, which, on further transformations, can be converted into the title compounds. Starting with L-serine provides the corresponding D-amino acids with complete enantiopurity. The reported method is economically viable and complements the existing methods, which rely largely on cross-coupling reactions.

Environmentally friendly and regioselective C3-alkylation of indoles with alcohols through a hydrogen autotransfer strategy

The direct alkylation of indoles using KOH and alcohols, as initial source of the electrophile, under solvent-free conditions is a safe and environmentally benign strategy for selective modification of these structures at the C3-position, without using hazardous and difficult to handle bromide or iodide derivatives or toxic and expensive transition metal catalysts. The protocol shows a broad scope, including halogenated indoles and secondary alcohols.

Relationship between stabilization energy and thermophysical properties of different imidazolium ionic liquids: DFT studies

Theoretical studies of thermophysical and thermodynamic properties of ionic liquid (ILs) have attracted considerable attention in recent times due to the possibility of prediction, which will immensely help in designing this ‘designer’s solvent’. Here, a new model is proposed to correlate an important thermophysical properties like melting point and density of the most popular class of ionic liquids, alkyl imidazolium halide with the calculated second order perturbation stabilization energy, E(2). This E(2) has been obtained from Natural Bond Orbital (NBO) analysis at B3LYP level of Density Functional Theory (DFT) calculation. This stabilization energy found to increase with decreasing alkyl chain length for chloride and iodide, though no straightforward trend was established for bromide containing imidazolium ILs. Interesting trends have been observed depending on the types of anion. While melting temperatures of chloride ILs were found to vary linearly with the E(2) values, corresponding iodide anion found to be fitted on an exponential curve. Further, alkyl chain length dependent E(2) values found to corresponds well with experimental density for chloride and iodide ILs. Density of chloride as well as iodide derivatives ILs found to be fitted well in an exponential curve with the E(2) values. The lack of correspondence between stabilization energy with experimental melting temperature or density for bromide derivatives might be due to the structural polymorphism.

Cold exposure lowers energy expenditure at the cellular level

Mitochondrial function is intimately involved in various metabolic processes and is therefore essential to maintain cell viability. Of particular importance is the fact that mitochondrial membrane potential (ΔΨm ) is coupled with oxidative phosphorylation to drive adenosine triphosphate (ATP) synthesis. We have examined the effects of cold temperature stress on ΔΨm and the role of cold temperature receptor expression on ΔΨm . Human bronchial endothelial cell line, BEAS-2B, and human embryonic kidney, HEK293, cell line were transfected with the gene for cold temperature responsive receptor protein TRPM8 or TRPA1, and exposed to cold temperature. ΔΨm was monitored using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazoyl carbocyanine iodide derivative (JC-10), a ΔΨm probe. While cold temperatures significantly increased ΔΨm and mitochondrial ATP levels in cells transfected with temperature responsive receptor TRPM8 or TRPA1, no change was noted in wild-type cells. Moreover, the change in ΔΨm and ATP level was a dynamic process. ΔΨm was raised to peak levels within 10 min of cold exposure, followed by a return to baseline levels at 30 min. Our findings suggest that cold temperature exposure increased mitochondrial ΔΨm via a mechanism involving cold temperature receptors.

ChemInform Abstract: Palladium‐Catalyzed Atom Transfer Radical Cyclization of Unactivated Alkyl Iodide.

AbstractA palladium‐catalyzed iodide atom transfer cyclization is achieved with a wide range of 5‐hexenyl iodides, delivering alkyl iodide derivatives in moderate to good yields.

Novel 1-(1-benzyl-1H-indol-3-yl)-N,N,N-trimethylmethanaminium iodides are competitive antagonists for the human α4β2 and α7 nicotinic acetylcholine receptors

This work presents the synthesis and the pharmacological characterization of a series of novel 1-(1-benzyl-1H-indol-3-yl)-N,N,N-trimethylmethanaminium iodide derivatives at the human (h) α7 and α4β2 nicotinic acetylcholine receptors (nAChRs). The inhibitory activity of the compounds was determined by Ca2+ influx assays on cells expressing either the hα7 or hα4β2 nAChR subtype. To determine whether the observed inhibitory activity is mediated by a competitive or non-competitive mechanism, additional radioligand binding assays were performed using [3H]methyllycaconitine, [3H]cytisine, and [3H]imipramine. The results established that the compounds inhibit the nAChRs by a competitive mechanism and that the potencies are higher for the hα7 nAChR compared to that for the hα4β2 nAChR. Substitutions with oxygenated functional groups on the benzene ring increase the receptor selectivity. In particular, the hydroxyl derivatives 4b and 4c present the highest selectivity for the hα7 nAChR subtype. Molecular docking results indicate that the hydroxyl group forms a hydrogen bond with the carbonyl group at α7-Gln116, but not at β2-Phe115, supporting the observed receptor selectivity at the molecular level.

Synthesis of γ‐Oxo γ‐Aryl and γ‐Aryl α‐Amino Acids from Aromatic Aldehydes and Serine

Abstractγ‐Oxo α‐amino acids and γ‐aryl α‐amino acids are compounds with very interesting biological properties and are active components of many drug molecules. Oxo amino acids are also used as synthetic precursors for a number of unnatural amino acids and amino alcohols. We report a very efficient synthesis of such compounds through the coupling of aromatic dithianes, prepared from aromatic aldehydes and an iodide derivative of serine. The dithiane groups in compounds thus obtained can be either hydrolyzed or reduced to generate 4‐oxo‐4‐aryl or 4‐aryl 2‐amino butanol derivatives, respectively, which, on further transformations, can be converted into the title compounds. Starting with L‐serine provides the corresponding D‐amino acids with complete enantiopurity. The reported method is economically viable and complements the existing methods, which rely largely on cross‐coupling reactions.

A Silver‐Catalyzed Spirocyclization of Alkynyl Silyl Enol Ethers

Ring out the old: The cycloisomerization of alkynyl silyl enol ethers proceeds at ambient temperature under the mild conditions of silver catalysis. Mono- or bicyclic spiro compounds can be obtained by 5-exo-dig reactions. Trapping the vinyl silver species with an iodide source, such as N-iodosuccinimide (NIS), afforded the alkenyl iodide derivatives.