Cyano Compounds Research Articles

Continuous Hydrogenation of Nitriles to Primary Amines with High Selectivity in Flow by Using Raney Cobalt

AbstractPrimary amines produced by selective catalytic hydrogenation of cyano compounds are widely used as basic chemicals, but due to the complexity of the hydrogenation mechanism and the inefficient mass transfer of the intermittent reaction, the process tends to produce secondary and tertiary amines as undesirable by‐products. In this research, a continuous hydrogenation system employing a micropacked‐bed reactor (μPBR) was established for the catalytic hydrogenation of 3‐ethylaminopropionitrile (3‐EAPN) to synthesize N‐ethyl‐1,3‐propanediamine (3‐EAPA). Under optimal experimental conditions using Raney cobalt as a catalyst, complete conversion of 3‐EAPN was achieved, and a high selectivity of 99.6 % for the primary amine (3‐EAPA) was obtained. On this basis, the system was extended with other cyano compounds of different structures as hydrogenation substrates, demonstrating the general applicability of this continuous hydrogenation system by using Raney cobalt as a catalyst in a μPBR for the hydrogenation of various nitriles.

Matrix of orthogonalized atomic orbital coefficients representation for radicals and ions.

Chemical (molecular, quantum) machine learning relies on representing molecules in unique and informative ways. Here, we present the matrix of orthogonalized atomic orbital coefficients (MAOC) as a quantum-inspired molecular and atomic representation containing both structural (composition and geometry) and electronic (charge and spin multiplicity) information. MAOC is based on a cost-effective localization scheme that represents localized orbitals via a predefined set of atomic orbitals. The latter can be constructed from such small atom-centered basis sets as pcseg-0 and STO-3G in conjunction with guess (non-optimized) electronic configuration of the molecule. Importantly, MAOC is suitable for representing monatomic, molecular, and periodic systems and can distinguish compounds with identical compositions and geometries but distinct charges and spin multiplicities. Using principal component analysis, we constructed a more compact but equally powerful version of MAOC-PCX-MAOC. To test the performance of full and reduced MAOC and several other representations (CM, SOAP, SLATM, and SPAHM), we used a kernel ridge regression machine learning model to predict frontier molecular orbital energy levels and ground state single-point energies for chemically diverse neutral and charged, closed- and open-shell molecules from an extended QM7b dataset, as well as two new datasets, N-HPC-1 (N-heteropolycycles) and REDOX (nitroxyl and phenoxyl radicals, carbonyl, and cyano compounds). MAOC affords accuracy that is either similar or superior to other representations for a range of chemical properties and systems.

Preparation and Identification of some heterocyclic compounds from cyano compounds

This article included prepared cyano acetic acid hydrazid from interaction cyano ethylacetate with hydrate hydrazen, and interaction with 2- acytel thiophene and 2- acytelpyridine it will formation of hydrazide- hydrazone derivative (I, II), and through the undergo the compounds (I,II) for chain of interactions with different chemical materials then enclosed cyclo formed derivative of (arylidene ,coumarin , aryl hydrazon , thiophene ) .
 Prepared compounds have been studied and Identification by physical and spectral means.

Metal-Free Photochemical Radical Cyclization for the Synthesis of Pyrrolo[3,2-c]-quinolines with One-Carbon Unit.

An efficient and environmentally-friendly method for carbon-centered radical cyclization of olefins via visible light photoredox catalysis to afford pyrrolo[3,2-c]-quinolines, oxindoles and quinoline-2,4-diones is described. This novel reaction successfully activated the α C-H bonds in one-carbon units such as esters, chlorinated hydrocarbons and cyano compounds via HAT (hydrogen atom transfer) process by means of aryldiazonium salts. The transformation features good functional group tolerance, broad substrate scope, high atom economy, no need for transition metal or high temperature.

Synthesis, reactivity, antimicrobial, and anti-biofilm evaluation of fluorinated 4-amino-3-mercapto-1,2,4-triazin-5(4H)-one and their derivatives

New fluorinated 1,2,4-triazin-4-ones 2–24 have been prepared using straightforward approaches. The reaction of 4-amino-3-mercapto-6-(trifluoromethyl)-1,2,4-triazin-5(4H)-one (2) with aromatic aldehydes produced 4-((4-substitutedbenzylidene)amino)-3-mercapto-6-(trifluoromethyl)-1,2,4-triazin-5(4H)-ones (5–9), which were cyclized by thioglycolic acid to give 2-(4-subsitiutedphenyl)-3-(3-mercapto-5-oxo-6-(trifluoromethyl)-1,2,4-triazin-4(5H)-yl)thiazolidin-4-ones (10–14). 7-Methyl-3-(trifluoromethyl)-4H-[1, 3, 4]thiadiazolo[2,3-c][1, 2, 4]triazin-4-one (4) was synthesized by the condensation of 2 with acetaldehyde or by reaction with cyano compounds, followed by self-cyclization in dry benzene. Cyclization of compound 2 by reaction with aromatic acids yielded 7-substitutedphenyl-3-(trifluoromethyl)-4H-[1, 3, 4]thiadiazolo[2,3-c][1, 2, 4]triazin-4-ones (15–19). Reaction of compound 2 with cyanamide produced 1-(4-oxo-3-(trifluoromethyl)-4H-[1, 3, 4]thiadiazolo[2,3-c][1, 2, 4]triazin-7-yl)guanidine (20). Alkylation of compound 2 with phenacyl bromide produced 4-amino-3-((2-oxo-2-phenylethyl)thio)-6-(trifluoromethyl)-1,2,4-triazin-5(4H)-one (21) which upon heating in the same media furnished 7-phenyl-3-(trifluoromethyl)-4H,8H-[1, 2, 4]triazino[3,4-b][1, 3, 4]thiadiazin-4-one (22). The reaction of Schiff′s bases 5 or 6 with phenacyl bromide gave 8-benzoyl-7-(4-halophenyl)-3-(trifluoromethyl)-4H,8H-[1, 2, 4]triazino[3,4-b][1, 3, 4]thiadiazin-4-ones (23–24). All of the newly synthesized compounds were characterized by spectral measurements and elemental analysis. The biological evaluation was also described. All compounds were screened for antibacterial, antifungal, and anti-biofilm activities. The findings confirm that the fluorinated 1,2,4-triazin-4-ones appear to be promising compounds as antibacterial, antifungal, and anti-biofilm agents.

Main group cyanides: from hydrogen cyanide to cyanido-complexes

Abstract Homoleptic cyanide compounds exist of almost all main group elements. While the alkali metals and alkaline earth metals form cyanide salts, the cyanides of the lighter main group elements occur mainly as covalent compounds. This review gives an overview of the status quo of main group element cyanides and cyanido complexes. Information about syntheses are included as well as applications, special substance properties, bond lengths, spectroscopic characteristics and computations. Cyanide chemistry is presented mainly from the field of inorganic chemistry, but aspects of chemical biology and astrophysics are also discussed in relation to cyano compounds.

Cyanide-Free Cyanation of sp2 and sp-Carbon Atoms by an Oxazole-Based Masked CN Source Using Flow Microreactors.

This work reports a cyanide-free continuous-flow process for cyanation of sp2 and sp carbons to synthesize aryl, vinyl and acetylenic nitriles from (5-methyl-2-phenyloxazol-4-yl) boronic acid [OxBA] reagent as a sole source of carbon-bound masked -CN source. Non-toxic and stable OxBA reagent is generated by lithiation-borylation of bromo-oxazole, and the consecutive Suzuki-Miyaura cross-coupling with aryl, vinyl, or acetylenic halides and demasking [4+2]/retro-[4+2] sequence were successfully accomplished to give the desired cyano compounds with reasonably good yields in a four-step flow manner. A unique feature of this cyanation protocol in flow enables to cyanate a variety of sp2 and sp carbons to produce a broad spectrum of aryl acetonitrile. It is envisaged that the OxBA based cyanation would replace existing unstable and toxic approaches as well as non-toxic cyanation using two different sources of "C" and "N" to incorporate the -CN group.

Chiral Fluorescent Metal-Organic Framework with a Pentanuclear Copper Cluster as an Efficient Luminescent Probe for Dy3+ Ion and Cyano Compounds.

Luminescent probes have been used for the detection of various heavy metals and toxic compounds. A novel sensor with excellent sensitivity and selectivity is in high demand. Herein, we designed and synthesized a three-dimensional copper-organic framework of "pcu" α-Po primitive cubic topology with a Schläfli symbol of {4.4.4.4.4.4.4.4.4.4.4.4.*.*.*}. By taking advantage of metal clusters and a triazole ligand as the metal-organic framework (MOF) components, the newly obtained MOF is stable in various environments and can be potentially used as the sensor. Remarkably, this MOF-based sensor shows high sensitivity and selectivity toward a dysprosium ion (Dy3+) in a multiple-lanthanide mixed solution. Besides, it exhibits luminescent quenching toward various cyano compounds. This chiral cluster-based network provides a potential luminescent probe for various inorganic and organic compounds with high sensitivity and selectivity.

Characterization of Nitrite-Related Reaction Products in Beer.

The effect of nitrites in foods and beverages still raises discussion due to the possible formation of harmful nitroso compounds. However, as most of these compounds in beer were not structurally characterized yet, the research about their toxicological relevance for consumers is limited. This study is focused on identification of the products formed by nitrite (or isotopically labeled nitrite 15N) reactions in beer using gas chromatography with tandem mass spectrometry. In total, 19 products were identified, and some of them were structurally characterized and confirmed by comparing retention indices and mass spectra of standard/synthesized compounds. Identified compounds were representatives of nitroso, nitro, oxime, and even cyano compounds. For the peaks which were not structurally identified, primary structural characteristics were also listed. Found products were further screened in 16 authentic beer samples which showed the apparent occurrence of found compounds in non-treated beers.

One-Pot Synthesis of Some New s-Triazole Derivatives and Their Potential Application for Water Decontamination.

A rapid, efficient, and one-pot protocol has been developed for the synthesis of cyclized 2,6-dimethyl-5-substituted-thiazolo[3,2-b]-s-triazoles (3a–c) through the interaction of 5-methyl-1H-s-triazole-3-thiol (1) with aliphatic ketones (2a–d) in refluxing acetic acid in the presence of a catalytic amount of sulfuric acid (AcOH/H+) while with aromatic ketones (5a–d), a mixture of uncyclized 3-methyl-s-triazolylthioacetophenone derivatives (6a–d) and cyclized 6-aryl-2-methyl-thiazolo[3,2-b]-s-triazoles (7a–d) has been produced. With this catalytic system, inexpensive sulfuric acid was utilized as a catalyst, which prevented the production of poisonous and irritating halo carbonyl compounds. On the other hand, the interaction of s-triazole 1 with cyano compounds (9a,b) afforded the corresponding 6-amino-2-methyl-5-substituted-thiazolo[3,2-b]-s-triazoles (10a,b). Similarly, treatment of 4-amino-3-methyl-s-triazole-5-thiol (12) with aliphatic and aromatic ketones (2c and 5a–e) afforded directly 3-methyl-7H-s-triazolo[3,4-b]-1,3,4-thiadiazines (13a and 14a–e). Further, reaction of 12 with cyano compounds (9a,b) under the same reaction conditions yielded the corresponding 3-methyl-s-triazolo[3,4-b]-1,3,4-thiadiazole derivatives (15a,b). The reaction mechanism was studied, and the structures of all novel compounds were verified using spectroscopy and elemental analysis. Moreover, the potential application of the synthesized compounds toward heavy metal ions and inorganic anion removal from aqueous solution has been investigated. The removal effectiveness for metal ions reached up to 76.29%, while for inorganic anions it reached up to 100%, indicating that such synthesized compounds are promising adsorbents for water remediation.

Amino-grafted Cu and Sc Metal-Organic Frameworks involved in the green synthesis of 2-amino-4H-chromenes. Mechanistic understanding

In this work, we report for the first time a new methodology for the eco-synthesis of 2-amino-4 H -chromenes 1 , from salycilaldehydes and cyano compounds, under solvent-free and mild conditions, using amino-grafted MOFs as catalysts. The selected MOFs − commercial CuBTC and MIL-100(Sc) previously synthetized in our laboratories − can be easily functionalyzed with amines of different nature showing notable differences in their composition and textural properties. The total or partial functionalization of the metal centers in starting MOFs is strongly depending on the functionalization method used. Our results indicate that the catalytic performance is mainly conditioned by the type and concentration of basic sites, porosity of the samples barely showing any influence. The methodology herein reported could be considered as an environmental friendly alternative to the selective chromene synthesis, which allows to achieve high yields in relatively short reaction times (up to 90% over 1 h), using notably small amounts of easily prepared catalysts. Furthermore, our experiments in combination with theoretical calculations strongly suggest that free-amine groups in ethylenediamine (EN) functionalized catalysts can act either as individual catalytic sites, as for EN-M/CuBTC sample, in which all metal centers are functionalized with EN ligands and shows the highest concentration of basic catalytic sites, or acting in cooperation with the closest metal centers in samples partially functionalized, as in the case of EN/CuBTC sample. • Amino-grafted MOFs are able to efficiently catalyze the chromene synthesis • Functionalization of selected MOF is strongly depending on the method used • Amine functions in MOF can be act as individual catalytic sites • A cooperation of amine groups with the nearest metal CUS probably takes place in the reaction

Alkaline-extracted cyanide from cassava wastewater and its sole induction of chromosomal aberrations in Allium cepa L. root tips

ABSTRACT Cassava, a staple crop in Nigeria, processed by numerous factories in rural and suburban locations is known to contain some level of cyano compounds. Lack of stringent environmental regulations on the management of cassava wastewater (CWW) from cassava-processing factories had led to its indiscriminate discharge on the environment. CWW samples were obtained from cassava-processing factories from selected states (Lagos (A), Oyo (B), Ogun 1 (C1), Ogun 2 (C2) and Cross River (D)) in Nigeria to determine the cytotoxic and genotoxic effects of extracted cyanide from the wastewaters. The cyanide was hydrolysed via chemical degradation utilizing 1.25 M NaOH and subsequently titrated using silver nitrate with p-dimethylaminobenzalrhodamine as indicator. Further, in order to explore the potential toxicity of this pollutant present in the effluent, a battery of short-term biological assay (Allium cepa chromosomal aberration test) was used. Bulbs with roots of Allium cepa L. were treated with different concentrations (0.05%, 0.1%, 0.2%, 0.4% and 0.8%) of CWW, and after 48 h, the root tips were processed for cytological studies by the aceto-orcein squash procedure. The results revealed that cyanide concentrations on re-fluxing were in the range of 1.0 and 1.3 mg/L. All concentrations induced a number of chromosomal aberrations in the root tip cells. The mitotic index decreased significantly (p < 0.05) with increasing concentration. The cytotoxic effects showed strong concentration-dependent root growth inhibition with EC50 values of 30%, 20%, 37%, 43% and 22% for A, B, C1, C2 and D, after 72 h. The findings thus indicate that alkali treatment is very efficient in degrading the cyanide content of CWW and has shown that the combination of physico-chemical analysis along with the sole toxicity assessment could provide valuable information about the sole toxicity of cyanide as a chemical pollutant present in the cassava effluent.

Styrylbenzene organogels and how the cyano groups tune the aggregation-induced emission

Fluorescence switching of π-gelators has emerged as a field of great interest because of their promising applications. In this work we present two families of luminogens based on bis(styrylbenzene) and bis(α-cyanostyryl)benzene that incorporate acetamido groups and hydrocarbon chains to induce gelation. The presence of cyano groups in the molecular skeleton produces Aggregation Induced Emission (AIE) from solution to the gel while their absence gives the Aggregation Caused Quenching (ACQ) effect. Density Functional Theory calculations were performed in order to shed light on the origin of these opposite phenomena. The bis(styrylbenzene) compound showed a high quantum yield in solution and nearly planar structure was theoretically predicted. A significant drop in the quantum yield was observed after gelation, probably due to the π-π intermolecular interactions favoured by the planar scaffold. In contrast, the more twisted structure predicted for the cyano compounds could prevent such π-π intermolecular interactions and this would favour fluorescence emission. In addition, the twisted molecular structure predicted for the cyano derivative could induce Z/E photosiomerisation that suppresses the emission in solution. However, the framework of intermolecular contacts that arises during the gelation process could restrict torsional motions to the detriment of photoisomerization, thus resulting in AIE-active compounds. Furthermore, the reorganisation energy and Huang–Rhys factors associated with the non-radiative relaxation were calculated. The highest values were found for some vibrational modes in the low energy region in the case of the cyano compound and these could contribute to the non-radiative relaxation in solution. These intramolecular motions could be blocked in the gel, thus increasing the fluorescence emission. The introduction of cyano groups in the carbon scaffold could therefore provide a strategy for the rational design of new active AIE organogels.

Synthesis of Aromatic Diketoximes and their Complexes with Nickel Salts

The diketoximes of 4,4'-diacetyldiphenyl oxide and 4,4'-diacetyldiphenyl sulfide were synthesized, the possibility of their use for the synthesis of simple and complex polyesters and polypyrroles, as well as the ability to complex with nickel salts. Organic chemistry used oximes in the 19th century, afterward, as an analytical reagent in the 20th century. Currently, oximes are superior to carbonyl compounds and alcohols in the variety of reactions and the widespread use in synthetic chemistry. Oximes easily turn into other classes of organic compounds – amines, cyano and nitro compounds, carbonyl compounds, heterocyclic compounds, including pyrroles, imidazoles, pyridines, they can be used as suitable compounds with salts of Cu (II), Ni (II), Zn (II), Cd (II), and Co (II). Oximes with complex heterocyclic and aromatic substituents are used as intermediates in fine organic synthesis. It should be noted that oximes have a wide spectrum of biocidal action and are used as anti-inflammatory, antiviral, antimicrobial agents, insecticides. Their versatile biological activity is considered in the preparation of antidepressant, sedative, vasodilator and other drugs [1].

Towards highly efficient hydrotalcite/hydroxyapatite composites as novel catalysts involved in eco-synthesis of chromene derivatives

A series of hydrotalcite/hydroxyapatite composites were investigated as novel catalysts in the green synthesis of chromenes in high conversions (up to 78% after 2 h), under solvent-free and mild conditions, from salycilaldehydes and cyano compounds. Materials were prepared by three different methods: impregnation of hydroxyapatite over hydrotalcite already crystallized; impregnation of hydrotalcite over hydroxyapatite and crystallization of both the components simultaneously. The composites resulted in the materials with high activity and selectivity for the 2-amino-4H-chromene synthesis. The catalytic performance was depending on the catalyst synthesis method and governed by the basicity of the samples and textural properties also varying as a function of the used cyano compound. Observed reactivity was attributed to the high dispersion of the hydrotalcite particles on the hydroxyapatite component, resulting in a considerable increase of the surface areas from 3 to 154 m2/g, and thus, given rising to a high concentration of superficial hydroxyls reaching 7.1 × 1014 sites/g catalyst. Broad pore size distributions in composites enabled a rapid diffusion of the reactants to reach the basic hydroxyl sites.

Recent Trends in the Iron‐Catalyzed Cyanation Reactions

AbstractThe review focuses on the iron‐catalyzed cyanation reaction. This is the first review on this topic and covers literature till 2020 and comprehends all the works published in this field detailing the scope and limitations. The cyano compounds are important organic moiety and are widely used in synthetic organic chemistry; this review aims to help understand the various aspects of Fe‐catalyzed cyanation reactions and its scope.magnified image

Enhanced catalytic performance of highly mesoporous hydrotalcite/SBA-15 composites involved in chromene multicomponent synthesis

Abstract A series of highly porous hydrotalcite/SBA-15 composites were synthesized and used as catalysts, for the first time, in the multicomponent synthesis of chromenes, from 2-hydroxybenzaldehydes and cyano compounds, with enolizable hydrogens, under solvent-free and mild conditions. The composites were prepared by ultrasound irradiation in the crystallization step, as non-conventional energy source, using different hydrotalcite/SBA-15 proportions. HT30-SBA composite, with lower hydrotalcite loading and high developed porosity, presented superior catalytic performance affording the corresponding chromenes in excellent conversions with total selectivity, after considerably decreased reaction times. The observed reactivity was mainly attributed to the high dispersion of small particles of hydrotalcite on the SBA-15 component, contributing to a great enhancement of the mesoporosity. The high dispersion promoted the increase of the surface area given rise to a high concentration of superficial hydroxyls as more accessible catalytic sites, responsible to the catalytic activity. Therefore, our results demonstrate that percentage of hydrotalcite component, dispersion of hydrotalcite nanoparticles and texture of the composites strongly influence the catalytic performance.

An Air-Stable N-Heterocyclic [PSiP] Pincer Iron Hydride and an Analogous Nitrogen Iron Hydride: Synthesis and Catalytic Dehydration of Primary Amides to Nitriles

An air-stable N-heterocyclic PSiP pincer iron hydride FeH(PMe3)2(SiPh(NCH2PPh2)2C6H4) (4) was synthesized by Si–H activation of a Ph-substituted [PSiP] pincer ligand. The analogous strong electron-donating iPr-substituted [PSiP] pincer ligand was prepared and introduced into iron complex to give an iron nitrogen complex FeH(N2)(PMe3)(SiPh(NCH2PiPr2)2C6H4) (6). Both 4 and 6 showed similar high efficiency for catalytic dehydration of primary amides to nitriles. Air-stable iron hydride 4 was the best catalyst for its stabilization and convenient preparation. A diverse range of cyano compounds including aromatic and aliphatic species was obtained in moderate to excellent yields. A plausible catalytic reaction mechanism was proposed.

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes.

In this review, direct cyanation, hydrocyanation, dicyanation, cyanofunctionalization and other cyanation reactions of alkynes were highlighted. Firstly, the use of nitriles and development of cyanation was simply introduced. After presenting the natural properties of alkynes, cyanation reactions of alkynes were classified and introduced in detail. Transition metal catalysed direct cyanation and hydrocyanation of alkynes gave alkynyl cyanides and alkenyl nitriles in good yields. Dicyanation of alkynes produced 1,2-dicyano adducts. Cyanofunctionalization of alkynes afforded functional cyanated compounds. Thiocyanation and selenocyanation yielded the expected functional vinylthiocyanates and vinylselenocyanates. A plausible reaction mechanism is presented if available.

Nitrogen-containing Anions and Tholin Growth in Titan’s Ionosphere: Implications for Cassini CAPS-ELS Observations

Abstract The Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument on board Cassini revealed an unexpected abundance of negative ions above 950 km in Titan’s ionosphere. In situ measurements indicated the presence of negatively charged particles with mass-over-charge ratios up to 13,800 u/q. At present, only a handful of anions have been characterized by photochemical models, consisting mainly of C n H− carbon chain and C n−1N− cyano compounds (n = 2–6); their formation occurring essentially through proton abstraction from their parent neutral molecules. However, numerous other species have yet to be detected and identified. Considering the efficient anion growth leading to compounds of thousands of u/q, it is necessary to better characterize the first light species. Here, we present new negative ion measurements with masses up to 200 u/q obtained in an N2:CH4 dusty plasma discharge reproducing analogous conditions to Titan’s ionosphere. We perform a comparison with high-altitude CAPS-ELS measurements near the top of Titan’s ionosphere from the T18 encounter. The main observed peaks are in agreement with the observations. However, a number of other species (e.g., CNN−, CHNN−) previously not considered suggests an abundance of N-bearing compounds, containing two or three nitrogen atoms, consistent with certain adjacent doubly bonded nitrogen atoms found in tholins. These results suggest that an N-rich incorporation into tholins may follow mechanisms including anion chemistry, further highlighting the important role of negative ions in Titan’s aerosol growth.