Isocyanide Research Articles

Experimental and kinetic modeling study of iso-propylamine oxidation with SVUV-time of flight mass spectrometry

Atmospheric oxidation experiments of iso-propylamine (IPA) were conducted in a jet-stirred reactor over the temperature range from 550 to 870 K at fuel-equivalence ratios of 0.5 and 2.0. A combination of synchrotron vacuum ultraviolet (SVUV) photoionization and time-of-flight mass spectrometry (TOFMS) was utilized to identify and quantify oxidation products and intermediates. Compared to the previous n-propylamine (NPA) low-temperature oxidation [Proc. Combust. Inst., 39 (2023) 295–303.], some intermediates and products were newly observed among the 34 detected species, including nitrosyl hydride, methylamine, acetonitrile, nitrous oxide, ethyl isocyanide, propanenitrile, 2-propanimine, n-methylformamide and 2-methylallylamine. A kinetic model consisting of 815 species and 4402 reactions was developed based on the iso-propanol model [Prog. Energy Combust. Sci. 67 (2018) 31–68.] and an ethylamine model [Prog. Energy Combust. Sci. 44 (2014) 40–102.]. The onset temperature of IPA and O2 consumption is 750 K under both lean and rich conditions. Rate-of-production (ROP) and sensitivity analyses were performed at 800 K to illustrate the reacting paths from parent fuel to major intermediates and products, and identify the most sensitive reactions. H2O2(+M) = 2OH(+M) is the most sensitive reaction with a promoting effect on IPA consumption while 2HO2 = H2O2+O2 is the most inhibiting one. Important N-containing pollutants like NH3, NOx, HCN, CH3NH2 and so on were analyzed with respect to their reaction routes. (CH3)2CNH is abundant due to the H-abstraction reactions between tC3H6NH2 radical with O2. This work was made for gaining a more comprehensive insight into the oxidation of IPA and make a foundation for further exploring amine chemistry.

Experimental study of nitropropane pyrolysis with molecular-beam mass spectrometry and tunable synchrotron VUV photoionization. Part I. The flow reactor pyrolysis of 1-nitropropane

An experimental study of 1-nitropropane (1-NP) pyrolysis was performed in a flow reactor at low pressure (4.0 kPa) in the temperature range of 623–973 K. The pyrolysis species was detected with the tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry (MBMS). Species from m/z = 15–87 were identified from near-threshold photoionization efficiency (PIE) spectra, such as radicals of CH3, C2H5, C3H5 and C3H7; isomers of C2H4O (ethenol and acetaldehyde), C3H6O (acetone and propanal), C4H10 (butane and isobutane), HNC (hydrogen isocyanide), HCN (hydrogen cyanide)), C3H5N (ethyl isocyanide and species with unidentified structure) and C3H5NO (methoxyacetonitrile and species with unidentified structure). Their mole fraction profiles were evaluated at different temperature. Based on the mole fractions of species measured at the minimum temperature of 1-NP pyrolysis, some new channels of 1-NP primary pyrolysis were speculated, such as the channels involving O-transfer from N to C-atoms in different positions, deoxygenation, dehydrogenation and OH-abstraction. Based on the mechanisms proposed in the literature, the species produced from secondary or subsequent reactions were also discussed. These results are valuable to a further quantum mechanical calculation for a better understanding of 1-NP chemistry.

Access to thiazoles via [3 + 2] cycloaddition of 1,2,3-thiadiazoles with isonitriles

The formal [3 + 2] cycloaddition of 1,2,3-thiadiazoles with isonitriles is developed to access structurally diverse 4,5-disubstituted thiazoles, in which the thioketene as a sulfo-2C-synthon is first disclosed.

Quasi-homogeneous catalytic conversion of CO2 into quinazolinones inside a metal–organic framework microreactor

Management of CO2 has been attracting great attention in this century.

Synthesis, Molecular Docking and Cytotoxic Activity Evaluation of Organometallic Thiolated Gold(I) Complexes.

The complex [(PhCH2NC)AuCl], 1, was prepared by the reaction of [(Me2S)AuCl], A, with an equimolar amount of benzyl isocyanide (PhCH2NC) ligand. Through a salt metathesis reaction, the chloride ligand in 1 was replaced by potassium benzothiazole-2-thiolate (Kbt) and potassium benzoimidazole-2-thiolate (Kbi) to afford complexes (PhCH2NC)Au(κ1-S-bt)], 2a and (PhCH2NC)Au(κ1-S-bi)], 2b, respectively, which were characterized by NMR spectroscopy. The cytotoxic activities of 2a and 2b were evaluated against three human cancer cell lines, including A549 (lung), SKOV3 (ovary), and MCF-7 (breast). Our results indicated that 2a exhibited comparable cytotoxicity on investigated cell lines with cisplatin. It showed a good anti-proliferative activity with IC50 of 19.46, 11.76 and 13.27 μM against A549, SKOV3 and MCF-7 cell lines, respectively. The effects of these complexes on the proliferation of the non-tumorigenic epithelial breast cell line (MCF-10A) showed their good selectivity between the tumorigenic and non-tumorigenic cell lines. Molecular docking simulation studies were also conducted to determine the specific binding site and binding mode of the synthesized gold complexes to DNA and thioredoxinreductase (TrxR) as their proposed targets.

Synthesis and Characterization of Some New Esters Containing Heterocyclic and Derived From Azo Dyes

This study including prepared new colored esters containing heterocyclic with high molecular weights. In the first part of work we synthesized azo dyes [1,2] from the reaction p-toluidine with β-naphthol and o-nitro phenol, thin we synthesized Schiff bases [3,4] by the reaction anthranilic acid with benzaldehyde and dimethyl benzaldehyde. The reaction azo dyes (contain OH group) with Schiff base (contain COOH group) these led to produce the new colored esters [A1-A4]. The second part of work was modification the (C=N-) group in esters to heterocyclic compounds by reacting with phenyl iso cyanide to produce new β-lactam [B1-B4] and with anthranilic acid to get new hydroquinazoline [C1-C4]. All these compounds were characterized by physical properties and spectral methods FTIR, 1H-NMR and 13C-NMR.

Phytochemical screening of Lycopersicum esculentum Mill. treated with seaweed liquid fertilizer

Premise of the study: The objective of the work is to manitor the phytochemicals present in methanolic extract of Lycopersicum esculentum after treatment with different concentrations of seaweed liquid fertilizer (SLF). Methods: In this study SLF treated L.esculentum were characterized through gas chromatography and mass spectroscopy to identify the phytochemicals constituents and functional groups of the compounds. Results: Preliminary phytochemical analysis revealed the presence of alkaloids, phenols, carbohydrates, saponins, glycosides, flavonoids, terpinoids. Among the thirty nine phytochemical constituents octa decanoic acid, stigmasterol, hexa decanoic acid and Vitamin E are relatively present in higher yield. The active phytochemical compounds and their constituents were identified with gas chromatography and mass spectrometry. The retention time, percentage of area, molecular weight and chemical formula of phytochemical compounds were determined with help of NIST08 and WILEY8 libraries. The functional groups identified from the spectrum techniques are alcohol, aldehyde, iso cyanides, alkyl compound and chloro compounds. Accordingly hexadecanic acid, beta.-amyrin, gamma sisterol, octodecanic acid, phytol, stigmasterol, vitamin E, lupeol were derived from SLF treated i.e. compared to control plants. Conclusion: The results of this study offer a platform of using SLF treated L.esculentum has an alternative source for various biological studies and it can be used as functional and pharmaceutical purposes.
 Keywords: SLF, Lycopersicum esculentum, Phytochemical, GC-MS and FTIR

Submillimeter wave spectroscopy of ethyl isocyanide and its searches in Orion

Context. About 40 cyanide compounds have been detected in the interstellar medium, but only 3 examples of organic isocyanide compounds were observed in this medium. Ethyl isocyanide is one of the best candidates for possible detection. Aim. To date, measurements of rotational spectra are limited to 40 GHz. The extrapolation of the prediction in the millimeter wave domain is inaccurate and does not permit an unambiguous detection. Methods. The rotational spectra were reinvestigated from 0.15 to 1 THz. Using the new prediction, we searched for the compound ethyl isocyanide in Orion KL and Sgr B2. Results. We newly assigned 2906 transitions and fitted these new data with those from previous studies, reaching quantum numbers up to J = 103 and Ka = 30. The asymmetric top Hamiltonian proposed by Watson in the Ir representation was used for the analysis, and both reductions A and S were tested. The search for CH3CH2NC in Sgr B2 (IRAM 30m) and Orion KL (IRAM 30m, ALMA Science Verification) result in a non-detection; upper limits to the column density were derived.

Behaviour of solid phase ethyl cyanide in simulated conditions of Titan

In order to simulate different altitudes in the atmosphere of Titan, we investigated using infrared spectrometry and mass spectrometry the photochemistry of ethyl cyanide (CH3CH2CN) ices at different temperatures. Heating experiments of the solid phase until complete desorption showed up three phase transitions with a first one appearing to be approximately at the temperature of Titan's surface (94 K), measured by the Huygens probe. Ethyl cyanide, whose presence has been suggested in solid phase in Titan, can be considered as another nitrile for photochemical models of the Titan atmosphere after our first study (Toumi et al., 2016) concerning vinyl cyanide (CH2CHCN). The desorption energy of ethyl cyanide has been calculated to be 36.75 ( ± 0.55) kJ mol−1 using IRTF and mass spectroscopical techniques. High energetic photolysis (λ > 120 nm) have been performed and we identified ethyl isocyanide, vinyl cyanide, cyanoacetylene, ethylene, acetylene, cyanhydric acid and a methylketenimine form as photoproducts from ethyl cyanide. The branching ratios of the primary products were determined at characteristic temperatures of Titan thanks to the value of the νCN stretching band strength of ethyl cyanide that has been calculated to be 4.12 × 10−18 cm molecule−1. We also report here for the first time the values of the photodissociation cross sections of C2H5CN for different temperatures.

ChemInform Abstract: An Efficient Passerini Tetrazole Reaction (PT‐3CR).

AbstractThe ultrasound‐mediated catalyst‐free Passerini‐type reaction of carbonyl compounds (I) and (IV) with isocyanides (II) and trimethylsilyl azide gives rise to tetrazoles (III) and (V).

ChemInform Abstract: Temperature‐Dependent Double Isocyanide Insertion Reaction to Construct a Polycyclic Skeleton.

AbstractThe Au‐catalyzed reaction of oxindolylideneacetates (I) with aryl isocyanides (II) in refluxing toluene leads to tricyclic derivatives (III), whilst the reaction at 95°C is accompanied by an oxygen migration to afford products (IV).

Imidazopyridines by SNAr Addition of Metalated Isonitriles to 2-Chloro Heterocycles

Key words imidazopyridines - nucleophilic aromatic substitution - isonitriles - alkylation

ChemInform Abstract: Palladium‐Catalyzed Cross‐Coupling Reaction of Azides with Isocyanides.

AbstractThe cross‐coupling reaction of isocyanides (II) with aryl, heteroaryl, benzyl, and alkyl azides leads to a variety of unsymmetrical carbodiimides in moderate to high yields.

ChemInform Abstract: Cobalt(II)/Silver Relay Catalytic Isocyanide Insertion/Cycloaddition Cascades: A New Access to Pyrrolo[2,3‐b]indoles.

AbstractA novel Co/Ag bimetallic catalyzed bicycloaddition of arylethynylanilines (I) and (IV) with isonitriles is presented.

ChemInform Abstract: An Efficient One Pot Three‐Component Nanocatalyzed Synthesis of Spiroheterocycles Using TiO2 Nanoparticles as a Heterogeneous Catalyst.

AbstractStructurally diverse spiroheterocycles, spiroannulated with imidazothiazole and imidazothiadiazole, are obtained by an environmentally benign isocyanide based domino protocol involving the three‐component reaction of benzothiazole (I)/thiadiazole (IX), isocyanides (II), and isatins (IV)/cyclic carbonyl compounds (V)/(VII).

ChemInform Abstract: Copper‐Catalyzed Tandem Synthesis of 2‐(Sulfonylimino)alkanamides from N‐Sulfonylketenimines and Alkyl Isocyanides.

AbstractN‐Sulfonylketenimines generated in situ from alkynes and azides are trapped by isocyanides to give 2‐(sulfonylimino)alkanamides in a one‐pot manner.

ChemInform Abstract: A New Multicomponent Reaction: Unexpected Formation of Derivatizable Cyclic α‐Alkoxy Isothioureas.

AbstractThe reaction of thiazoline S‐monoxides with isonitriles gives cyclic α‐alkoxy isothioureas.

ChemInform Abstract: Reversal of Diastereoselectivity in the Synthesis of Peptidomimetic 3‐Carboxamide‐1,4‐benzodiazepin‐5‐ones.

AbstractStarting from azido‐ or nitrobenzoic acids (I), isocyanides (II), glyoxals (III), and chiral methylbenzyl amine (IV), both diastereomers of benzodiazepinones [(VI) and (VII)] can be synthesized with a reversal of diastereoselectivity using different cyclization.

ChemInform Abstract: Organocatalytic α‐Addition of Isocyanides to Aldehydes.

ChemInform Abstract: Organocatalytic α‐Addition of Isocyanides to Aldehydes.

ChemInform Abstract: A Cation‐Directed Two‐Component Cascade Approach to Enantioenriched Pyrroloindolines.

AbstractUsing TBAB as the cationic catalyst and aryl isocyanides (II) gives pyrroloindolines (III) with good diastereoselectivity while alkyl isocyanides (V) give 1:1 mixtures of diastereomers (VI).