Reaction Of Nitriles Research Articles

Hydroxyl‐terminated Polybutadiene Curing by 1,3‐dipolar Cycloaddition of Energetic Nitrile N‐Oxides: Room Temperature Curing Property, Kinetics, Thermodynamics, and Propellant Combustion Characteristics

Abstract5‐nitro‐1,3‐benzenedichloroaldehyde oxime was designed and synthesized to achieve room temperature curing of HTPB binders, and its structures were characterized. A new kind of 1,3‐dipolar cycloaddition reaction system was formed by HTPB as main resin, 5‐nitro‐1,3‐benzenedichloroaldehyde oxime and triethylamine as curing agent. The results revealed that the formation of isoxazoline ring in cured HTPB elastomers mainly derived form the reaction of Nitrile N‐Oxide with cis alkene of HTPB, and the cured HTPB elastomers underwent three stages decomposition. The kinetic parameters and thermodynamic parameters for the 14 % curing agent's sample were obtained from the DSC data. The activation energy was computed to be 204.75 kJ mol−1 and pre‐exponential factor was 1.38×1023 s−1.The burning rate of the propellant showed that the propellant with HTPB cured by containing −NO2 Nitrile N‐Oxides (100 % HTPB, 14 % Nitrile N‐Oxides, 2 % Aluminum and 77 % Ammonium perchlorate, Curing at 25 °C for 5 days ) had a higher burning rate and pressure exponent compared to conventional HTPB propellant (100 % HTPB, 14 % toluene diisocyanate, Nitrile N‐Oxides, 2 % Aluminum and 77 % Ammonium perchlorate, Curing at 60 °C for 5 days). Therefore, the containing −NO2 Nitrile N‐Oxides curing system could be used as a novel promising curing system for HTPB‐based solid composite propellants.

A New One‐Pot Synthesis of Tetrasubstituted Pyrazines by the Ti‐Catalyzed Reaction of Aromatic and Benzyl‐Substituted Nitriles with EtAlCl2

AbstractA new one‐pot catalytic synthesis of tetrasubstituted pyrazines based on reaction of nitriles with EtAlCl2 in the presence of metallic Mg and the Cp2TiCl2 catalyst with good yields (60‐90%) has been developed. The probable mechanistic scheme for the formation of substituted pyrazines is proposed.

Fe(ClO4)3·H2O-Catalyzed Ritter Reaction: A Convenient Synthesis of Amides from Esters and Nitriles

An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with esters catalyzed by Fe(ClO4)3·H2O is described. Fe(ClO4)3·H2O is an economically efficient catalyst for the Ritter reaction under solvent-free conditions. Reactions of a range of esters (benzyl, sec-alkyl, and tert-butyl esters) with nitriles (primary, secondary, tertiary, and aryl nitriles) were performed to provide the corresponding amides in high to excellent yields.

An efficient synthesis of N-tert-butyl amides by the reaction of tert-butyl benzoate with nitriles catalyzed by Zn(ClO4)2·6H2O

An efficient, mild and inexpensive synthesis of N-tert-butyl amides from the reaction of nitriles (aryl, benzyl and sec-alkyl nitriles) with tert-butyl benzoate catalyzed by the employment of 2 mol% Zn(ClO4)2·6H2O at 50 °C under the solvent-free conditions is described. The reaction with aryl nitriles was carried out well and afforded the N-tert-butyl amides in 87–97% yields after 1 h. The benzyl and sec-alkyl nitriles also proceeded well and produced the N-tert-butyl amides in 83–91% yields after 5 h.

FeCl2·4H2O catalyzed ritter reaction with nitriles and halohydrocarbons

An efficient and inexpensive synthesis of N-substituted amides from the Ritter reaction of nitriles with various halohydrocarbons catalyzed by FeCl2·4H2O is described. FeCl2·4H2O economically efficiently catalyzed the Ritter reaction under solvent-free conditions. A range of halohydrocarbons (benzyl, tert-butyl and sec-alkyl halohydrocarbons) were coupled with nitriles to provide the corresponding amides in high to excellent yields.

Convenient synthesis of amides by Zn(ClO4)2·6H2O catalysed Ritter reaction with nitriles and halohydrocarbons

A convenient and high yielding procedure for the synthesis of amides by the Ritter reaction of nitriles and halohydrocarbons in the presence of Zn(ClO4)2·6H2O as a highly stable, effective and available catalyst is described.

A highly selective and ratiometric molecular probe for cyanide sensing based on a phenothiazine-hemicyanine dye

A new ratiometric fluorescent probe was designed based on hemicyanine moiety as a cyanide reaction site for nucleophilic addition. The titration experiment for CN- showed this probe exhibits high selectivity, a low limit of detection to 20 nM and quick response for CN- sensing. At the addition of CN-, the colour of the solution changed from purple to colourless, accompanied by an increase in the fluorescence intensity. The sensing behavior was investigated by changes of UV–vis spectra, HRMS and 1H NMR. Furthermore a HepG2 cell imaging experiment demonstrated the application prospect for tracing cyanide anions in biological systems.

Myeloperoxidase-catalyzed oxidation of cyanide to cyanate: A potential carbamylation route involved in the formation of atherosclerotic plaques?

Protein carbamylation by cyanate is a post-translational modification associated with several (patho)physiological conditions, including cardiovascular disorders. However, the biochemical pathways leading to protein carbamylation are incompletely characterized. This work demonstrates that the heme protein myeloperoxidase (MPO), which is secreted at high concentrations at inflammatory sites from stimulated neutrophils and monocytes, is able to catalyze the two-electron oxidation of cyanide to cyanate and promote the carbamylation of taurine, lysine, and low-density lipoproteins. We probed the role of cyanide as both electron donor and low-spin ligand by pre-steady-state and steady-state kinetic analyses and analyzed reaction products by MS. Moreover, we present two further pathways of carbamylation that involve reaction products of MPO, namely oxidation of cyanide by hypochlorous acid and reaction of thiocyanate with chloramines. Finally, using an in vivo approach with mice on a high-fat diet and carrying the human MPO gene, we found that during chronic exposure to cyanide, mimicking exposure to pollution and smoking, MPO promotes protein-bound accumulation of carbamyllysine (homocitrulline) in atheroma plaque, demonstrating a link between cyanide exposure and atheroma. In summary, our findings indicate that cyanide is a substrate for MPO and suggest an additional pathway for in vivo cyanate formation and protein carbamylation that involves MPO either directly or via its reaction products hypochlorous acid or chloramines. They also suggest that chronic cyanide exposure could promote the accumulation of carbamylated proteins in atherosclerotic plaques.

Tetracyanomethane under Pressure: Extended CN Polymers from Precursors with Built-in sp3 Centers.

Tetracyanomethane, C(CN)4, is a tetrahedral molecule containing a central sp3 carbon that is coordinated by reactive nitrile groups that could potentially transform to an extended CN network with a significant fraction of sp3 carbon. High-purity C(CN)4 was synthesized, and its physiochemical behavior was studied using in situ synchrotron angle-dispersive powder X-ray diffraction (PXRD) and Raman and infrared (IR) spectroscopies in a diamond anvil cell (DAC) up to 21 GPa. The pressure dependence of the fundamental vibrational modes associated with the molecular solid was determined, and some low-frequency Raman modes are reported for the first time. Crystalline molecular C(CN)4 starts to polymerize above ∼7 GPa and transforms into an interconnected disordered network, which is recoverable to ambient conditions. The results demonstrate feasibility for the pressure-induced polymerization of molecules with premeditated functionality.

Copper-Mediated Reactions of Nitriles with Nitromethanes: Aza-Henry Reactions and Nitrile Hydrations.

In this study, the first aza-Henry reaction of nitriles with nitromethane in a CuI/Cs2CO3/DBU system is described. The process was conveniently and directly used for the synthesis of β-aminonitroalkenes 2a-x and tolerated aryl-, alkyl-, hetaryl-, alkenyl-, and alkynylnitriles. The resulting aminonitroalkenes 2 could be successfully transformed to the corresponding 2-nitroacetophenones, 2-amino-1-halonitroalkenes, 2-alkylaminonitroalkenes, or 3-nitropyridines. In the presence of H2O, the aza-Henry reaction turned the reaction path to the nitrile hydration to exclusively yield the amides 3a-s.

Fe3O4/MIL‐101(Fe) nanocomposite as an efficient and recyclable catalyst for Strecker reaction

A highly porous metal‐organic framework, MIL‐101(Fe), was prepared by a solvothermal method in the presence of amino‐modified Fe3O4@SiO2 nanoparticles, in order to achieve Fe3O4/MIL‐101(Fe) nanocomposite, which was characterized by XRD, FT‐IR, SEM, TEM, BET, and VSM. This hybrid magnetic nanocomposite was employed as heterogeneous catalyst for α‐amino nitriles synthesis through three‐component condensation reaction of aldehydes (ketones), amines, and trimethylsilyl cyanide in EtOH, at room temperature. The recoverability and reusability was admitted for the heterogeneous magnetic catalyst; no significant reduction of catalytic activity was observed even after five consecutive reaction cycles.

MAC反応剤を用いた触媒的不斉炭素-炭素結合形成反応

MAC反応剤を用いた触媒的不斉炭素-炭素結合形成反応

Cobalt-catalyzed regioselective syntheses of indeno[2,1-c]pyridines from nitriles and diynes bearing propargyl fragments.

A highly efficient CoI2/o-phenanthroline catalyzed cycloaddition reaction of diynes bearing TBS protected propargylic alcohol fragments with nitriles has been developed. This methodology offers regioselective access, with good functional group tolerance, to various indeno[2,1-c]pyridine derivatives in moderate to excellent yields. It was found that o-phenanthroline as a bidentate nitrogen ligand showed high efficacy in this cycloaddition reaction.

Aza Diels-Alder Reactions of Nitriles, N,N-Dimethylhydrazones, and Oximino Ethers. Application in Formal [2 + 2 + 2] Cycloadditions for the Synthesis of Pyridines.

Metal-free, formal [2 + 2 + 2] cycloaddition strategies for the synthesis of polycyclic pyridine derivatives are described. The overall transformation proceeds via a two-stage pericyclic cascade mechanism. In the first step, an intramolecular propargylic ene reaction generates a vinylallene that is necessarily locked in the s-cis conformation. This vinylallene exhibits exceptional reactivity as a Diels-Alder reaction partner and engages in [4 + 2] cycloadditions with normally unreactive azadienophiles including unactivated cyano groups and heterosubstituted imine derivatives such as dimethylhydrazones and oximino ethers. Few examples of oximino ether Diels-Alder reactions have been reported previously, and normal electron-demand [4 + 2] cycloadditions of unactivated dialkylhydrazones are unprecedented. Overall, this metal-free formal [2 + 2 + 2] cycloaddition provides access to polycyclic pyridine derivatives and complements transition-metal-catalyzed [2 + 2 + 2] strategies.

Kinetic Modeling of the Alkaline Decomposition and Cyanidation of Argentian Plumbojarosite

The used sample was a solid plumbojarosite-argentian jarosite-hydronium jarosite solution. The stoichiometry of the alkaline decomposition and cyanide reaction in alkaline medium were studied. Alkaline decomposition shows an induction period, as well as a conversion period. Results on the reaction order and activation energy are consistent with the spherical particle model with decreasing core and chemical control. Six partial models and three global models were developed in order to describe its basic behavior. In every case the models were validated and tested for a plumbojarosite conversion of X = 0.75.

Interaction of HydSL hydrogenase from Thiocapsa roseopersicina with cyanide leads to destruction of iron-sulfur clusters

The effects of cyanide on enzymatic activity and absorption spectra in the visible and mid-IR (2150–1850cm−1) regions were characterized for purified HydSL hydrogenase from the purple sulfur bacterium Thiocapsa (T.) roseopersicina BBS. Prolonged incubation (over hours) of T. roseopersicina hydrogenase with exogenous cyanide was shown to result in an irreversible loss of activity of the enzyme in both the oxidized (as isolated) and H2-reduced states. The frequency position of the active site CO and CN− ligand stretching bands in the Fourier transform infrared (FTIR) spectrum of the oxidized form of hydrogenase was not influenced by cyanide treatment. The 410-nm absorption band characteristic of hydrogenase iron‑sulfur clusters showed a bleaching concomitantly with cyanide inactivation. A new band at 2038cm−1 was present in the FTIR spectrum of the cyanide-inactivated preparation, which band is assignable to ferrocyanide as a possible product of a destructive interaction of hydrogenase with cyanide. The results are interpreted in terms of a slow destruction of iron‑sulfur clusters of hydrogenase in the presence of cyanide accompanied by a release of iron ions in the form of ferrocyanide into the surrounding solution. Such a slow and irreversible cyanide-dependent inactivation seems to be complementary to a recently described rapid, reversible inhibitory reaction of cyanide with the active site of hydrogenases [S.V. Hexter, M.-W. Chung, K.A. Vincent, F.A. Armstrong, J. Am. Chem. Soc. 136 (2014) 10470–10477].

Synthesis of Sulfur Perfluorophenyl Compounds Using a Pentafluorobenzenesulfonyl Hypervalent Iodonium Ylide.

A novel pentafluorobenzenesulfonyl hypervalent iodonium ylide 3 was designed and synthesized as a useful tool for the preparation of sulfur pentafluorophenyl compounds containing a C6F5S or C6F5SO2 unit. Electrophilic pentafluorophenylthiolation of enamines, formal [3+2] cycloaddition reaction of nitriles and alkynes, and intramolecular SNAr cyclization were achieved using iodonium ylide 3. The fluoro-click reaction was also demonstrated using one of the products via an intermolecular SNAr reaction with heterocentered nucleophiles.

Continuous Flow Synthesis under High-Temperature/High-Pressure Conditions Using a Resistively Heated Flow Reactor

A cheap, easy-to-build, and effective resistively heated reactor for continuous flow synthesis at high temperature and pressure is herein presented. The reactor is rapidly heated directly using an electric current and is capable of rapidly delivering temperatures and pressures up to 400 °C and 200 bar, respectively. High-temperature and high-pressure applications of this reactor were safely performed and demonstrated by selected transformations such as esterifications, transesterifications, and direct carboxylic acid to nitrile reactions using supercritical ethanol, methanol, and acetonitrile. Reaction temperatures were between 300 and 400 °C with excellent conversions and good to excellent isolated product yields. Examples of Diels–Alder reactions were also carried out at temperatures up to 300 °C in high yield. No additives or catalysts were used in the reactions.

Hydrogen Sulfide Chemistry in Continuous Flow: Efficient Synthesis of 2-Oxopropanethioamide

A safe and scalable procedure for the synthesis of 2-oxopropanethioamide, an intermediate in the synthesis of a potent β-secretase (BACE-1) inhibitor, from the reaction of acetyl cyanide with hydrogen sulfide gas under continuous-flow conditions has been developed. The toxic gas could be accurately dosed using a mass-flow controller or a peristaltic pump. The reaction proceeded smoothly at room temperature in the presence of a small amount of triethylamine as basic catalyst. After a residence time of 15 min, excellent yield (96%) and purity (>99%) were obtained for the target compound. The high reaction selectivity permitted a simple workup procedure consisting of evaporation of all volatiles.

Preparation and application of a magnetic organic-inorganic hybrid nanocatalyst for the synthesis of α-aminonitriles

This article is the first report of the catalytic application of copper ferrite-coated chitosan in organic reactions as a bio-nanocomposite. CuFe2O4/chitosan was used as a hybrid nanocatalyst for the multicomponent Strecker synthesis of α-aminonitriles by using aryl aldehydes, trimethylsilyl cyanide (TMSCN) and aromatic amines at room temperature in ethanol as a green solvent. The catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The nanocatalyst was recovered and reused several times without significant loss of catalytic activity. The organic products were obtained easily without need for column chromatography in good-to-excellent yields. A facile and highly efficient synthesis of α-aminonitriles is reported via a one-pot threecomponent condensation reaction of aryl aldehydes, trimethylsilyl cyanide and aniline at room temperature in the presence of CuFe2O4/chitosan as a hybrid nanocatalyst in ethanol as a green solvent.