Alkylation Of Aniline Research Articles

Alkylation of aniline with methanol in the presence of FeCl3 · 6H2O in carbon tetrachloride

The reaction of aniline with methanol in the presence of FeCl3 · 6 H2O in carbon tetrachloride leads to the formation of N-methyl- and N,N-dimethylanilines and 4,4′-methylenebis(N,N-dimethylaniline).

ChemInform Abstract: Room Temperature and Solvent‐Free Iridium‐Catalyzed Selective Alkylation of Anilines with Alcohols.

AbstractA novel bidentate iridium NHC‐phosphine complex is developed, which appears to be an efficient catalyst for the N‐alkylation of anilines with alcohols.

N-alkylation of ammonia and amines with alcohols catalyzed by Ni-loaded CaSiO3

Nickel nanoparticles loaded onto calcium silicate (Ni/CaSiO3) have been prepared by ion-exchange method followed by in situ H2-reduction of the calcined precursor. Ni/CaSiO3 was found to be effective for the catalytic direct synthesis of primary amines from alcohols and NH3 under relatively mild conditions. Various aliphatic alcohols are tolerated, and the turnover number (TON) was higher than those of Ru-based homogeneous catalysts. The catalyst was recoverable and was reused. Effects of the surface oxidation states and particle size of Ni on the catalytic activity were studied by infrared (IR) investigation of the states of adsorbed CO and transmission electron microscopy (TEM). It is clarified that the surface Ni0 sites on small (3nm) sized Ni nanoparticles are the catalytically active species. Ni/CaSiO3 was also effective for the alkylation of anilines and aliphatic amines with various alcohols (benzyl and aliphatic alcohols) under additive free conditions; primary amines were converted into secondary amines and secondary amines into tertiary amines.

Use of Primary Amines for the Selective N-Alkylation of Anilines by a Reusable Heterogeneous Catalyst

Traditionally, anilines can be alkylated with reactive alkyl halides but now more safe reagents such as alcohols or even amines can be used. To overcome the limits of homogeneous catalysis for aniline N-alkylation, we have developed a protocol that employs simple Pd/C as a heterogeneous catalyst under microwave dielectric heating. The process, based on the easy Pd-mediated oxidation of primary amines to imines followed by aniline addition, is characterized by a high atom economy as ammonia is the only other product of the reaction. This kind of aniline alkylation with amines has been carried out both in ionic liquid medium using [bmim]PF₆ or in a more traditional solvent such as THF where the catalyst could be successfully recycled more times. The reusability of the catalyst was further confirmed by using material recycled from the amination in a standard alkene hydrogenation without loss of efficiency.

Effect of alumina support on catalytic performance of Pt-Sn/Al2O3 catalysts in one-step synthesis of N-phenylbenzylamine from aniline and benzyl alcohol

The effect of alumina on the catalytic performance of Pt-Sn/Al 2 O 3 catalysts in the green synthesis of secondary amines by N -alkylation of amines with alcohols based on the borrowing hydrogen strategy was investigated. N -alkylation of aniline with benzyl alcohol to produce N -phenylbenzylamine was used as a model reaction. Three different alumina supports were selected, and the corresponding catalysts were prepared by complex impregnation under vacuum. The supports and catalysts were characterized using N 2 adsorption-desorption, mercury intrusion porosimetry, X-ray diffraction, transmission electron and scanning electron microscopies, CO chemisorption, H 2 temperature-programmed reduction, and NH 3 temperature-programmed desorption. The results show that the catalysts with small Pt particles that were highly dispersed on the alumina supports and interacted weakly with the supports had high catalytic activities. The large pore volumes and pore size distributions of the alumina supports helped diffusion and adsorption of the reactants on the catalyst surface and increased the catalytic activity; they also promoted removal of the products from the catalyst surface and enhanced the catalytic stability. However, strong acidity and acid distribution of the alumina supports decreased the selectivity for secondary amines and reduced the catalyst stability. Pt-Sn/Al 2 O 3 catalysts with highly dispersed Pt particles, weak acid sites, acid distributions, and large pore volumes and pore size distributions have excellent catalytic performance in the synthesis of secondary amines.

Crossover temperature (TCO) and temperature gradient of refractive indices and length to breadth ratio of 4O.m mesomorphic compounds – an optical study

Refractive indices as a function of temperature are measured in a number of liquid crystals which belong to the N-(p-n-butoxy benzylidene)-p-n alkyl anilines, 4O.m compounds of the famous Schiff’s base nO.m liquid crystal compounds with m = 4 to 10 and 12. The temperature gradient of refractive indices, dne/dT and dno/dT, of these compounds are estimated. It is well known that in the case of dno/dT, there exists a crossover temperature, TCO, which exhibits an odd–even effect with the alkyl chain length as expected. Further, using the birefringence data, the length to breadth ratio, k, for these compounds is estimated, which shows not exactly even–odd effect but irregular change with the chain number. The results are discussed with the body of the data.

Heterogeneous Ni Catalysts for N-Alkylation of Amines with Alcohols

Nickel nanoparticles loaded onto various supports (Ni/MOx) have been prepared and studied for the N-alkylation of amines with alcohols. Among the catalysts, Ni/θ-Al2O3 prepared by in situ H2-reduction of NiO/θ-Al2O3 shows the highest activity, and it acts as reusable heterogeneous catalyst for the alkylation of anilines and aliphatic amines with various alcohols (benzyl and aliphatic alcohols) under additive free conditions. Primary amines are converted into secondary amines and secondary amines into tertiary amines. For the reaction of aniline with an aliphatic alcohol the catalyst shows higher turnover number (TON) than precious metal-based state-of-the-art catalysts. Mechanistic studies suggest that the reaction proceeds through a hydrogen-borrowing mechanism. The activity of Ni catalysts depends on the nature of support materials; acid–base bifunctional supports give higher activity than basic or acidic supports, indicating that acid–base sites on supports are necessary. The presence of basic (pyridin...

Synchronizing Steric and Electronic Effects in {RuII(NNNN,P)} Complexes: The Catalytic Dehydrative Alkylation of Anilines by Using Alcohols as a Case Study

A series of new hexacoordinated {Ru(II)(NNNN,P)} complexes was prepared from [RuCl(2)(R(3)P)(3)]. Their structure was determined by X-ray crystallography. The catalytic potential of this new class of complexes was tested in the alkylation of aniline with benzyl alcohol. In this test reaction, the influence of the counteranion plus electronic influences at the tetradentate ligand and the phosphine ligand were examined. The electrochemistry of all complexes was studied by cyclic voltammetry. Depending on the substituent at the ligand backbone, the complexes showed a different behavior. For all N-benzyl substituted complexes, reversible Ru(II/III) redox potentials were observed, whereas the N-methyl substituted complex possessed an irreversible oxidation event at small scan rates. Furthermore, the electronic influence of different substituents at the ligand scaffold and at the phosphine on the Ru(II/III) redox potential was investigated. The measured E(0) values were correlated to the theoretically determined HOMO energies of the complexes. In addition, these HOMO energies correlated well with the reactivity of the single complexes in the alkylation of aniline with benzyl alcohol. The exact balance of redox potential and reactivity appears to be crucial for synchronizing the multiple hydrogen-transfer events. The optimized catalyst structure was applied in a screening on scope and limitation in the catalytic dehydrative alkylation of anilines by using alcohols.

Room temperature and solvent-free iridium-catalyzed selective alkylation of anilines with alcohols

A bidentate iridium NHC-phosphine complex has been developed and applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols and to the N-heterocyclization of amino alcohols. This reaction resulted in high isolated product yields, even at room temperature and under solvent-free conditions.

Palladium-Catalyzed Regioselective Carbonylation of C–H Bonds of N-Alkyl Anilines for Synthesis of Isatoic Anhydrides

A Pd-catalyzed regioselective C-H bond carbonylation of N-alkyl anilines for the synthesis of isatoic anhydrides has been developed. The key Pd-catalyst intermediate has been isolated and characterized. This novel Pd-catalyzed carbonylation reaction tolerates a wide range of functional groups and is a reliable method for the rapid elaboration of readily available N-alkyl anilines into a variety of substituted isatoic anhydrides under mild conditions.

A Highly Active Bifunctional Iridium Complex with an Alcohol/Alkoxide‐Tethered N‐Heterocyclic Carbene for Alkylation of Amines with Alcohols

A series of new iridium(III) complexes containing bidentate N-heterocyclic carbenes (NHC) functionalized with an alcohol or ether group (NHC-OR, R = H, Me) were prepared. The complexes catalyzed the alkylation of anilines with alcohols as latent electrophiles. In particular, biscationic Ir(III) complexes of the type [Cp*(NHC-OH)Ir(MeCN)](2+)2[BF(4)(-)] afforded higher-order amine products with very high efficiency; up to >99% yield using a 1:1 ratio of reactants and 1-2.5 mol % of Ir, in short reaction times (2-16 h) and under base-free conditions. Quantitative yields were also obtained at 50 °C, although longer reaction times (48-60 h) were needed. A large variety of aromatic amines have been alkylated with primary and secondary alcohols. The reactivity of structurally related iridium(III) complexes was also compared to obtain insights into the mechanism and into the structure of possible catalytic intermediates. The Ir(III) complexes were stable towards oxygen and moisture, and were characterized by NMR, HRMS, single-crystal X-ray diffraction, and elemental analyses.

Non-catalytic alkylation of phenol and aniline with 1-hydroxymethylpyrazole

The IR spectrum of compound IV contains characteristic absorption bands of the hydroxy group and aromatic ring at 3100–3300 and 1600 cm, respectively. In the H NMR spectrum of compound IV there is a signal of OH proton in a weak field (9.46 ppm), which indicates that the C-alkylation of the aromatic ring occurs. The integral intensities of the benzene ring protons show the formation of the ortho-substituted isomer. In the H NMR spectrum of compound IV there are also the signals of the pyrazole ring protons (6.15, 7.33, and 7.55 ppm). DOI: 10.1134/S1070363212070274

Phase Transition Studies and Thermodynamic Parameters of Four Members of nO.m Series—A Dilatometric Study

Density measurements are carried out on four alkoxy benzylidene alkyl anilines, viz., N-(p-n-methoxy/ethoxybenzylidene)-p-n-dodecyl and tetradecylanilines, 1O.12, 1O.14, 2O.12, and 2O.14. The first three compounds exhibit monovariant nematic phase while the last compound exhibits nematic and smectic-A phase with variable thermal ranges. The density measurements infer the first order nature for Isotropic to nematic (Iso-N) phase transformation while the nematic to smetic-A (N-SmA) transition as weak first order. Thermal expansion coefficient α estimated from density ρ is utilized for the computation of thermodynamic parameters of above liquid crystalline compounds. The temperature variation of different thermodynamic parameters like Moelwyn-Hughes parameter, reduced volume, reduced compressibility, isothermal, isochoric, and isobaric Gruneisan parameters, etc., are estimated. The results are compared with the available data in literature of other compounds.

ChemInform Abstract: Lithium Perchlorate—Nitromethane‐Promoted Alkylation of Anilines with Arylmethanols.

AbstractThe selective formation of N‐alkylated anilines (III), double Friedel—Crafts alkylation products such as (IV) and (VI) or N—C‐alkylated compound (V) is achieved by changing the temperature, the stoichiometry of reactants, and the time.

Heterogeneously Catalyzed One-Pot Synthesis of <em>N</em>-alkyl anilines from Nitroaromatics by Assembled Pt<sub>3</sub>Sn/Al<sub>2</sub>O<sub>3</sub> Catalyst

Heterogeneously Catalyzed One-Pot Synthesis of <em>N</em>-alkyl anilines from Nitroaromatics by Assembled Pt<sub>3</sub>Sn/Al<sub>2</sub>O<sub>3</sub> Catalyst

Non-catalytic alkylation of aniline with 1,3,5-trimethyl-4-hydroxymethylpyrazole

The electron density in the benzene ring, preferably in the orthoand para-positions, is known to be increased in benzenes containing activating groups as substituents. For this reason, the reaction of electrophilic substitution in anilines, phenols, alkylbenzenes, and related derivatives occurs in the orthoand para-positions of the ring [1]. As it was shown earlier [2], the noncatalytic alkylation of phenol with 1,3,5-trimethyl-4-hydroxymethylpyrazole I proceeded similarly to give C-alkylation products as a mixture of ortho-and para-isomers with a yield of 67%.

Lithium perchlorate-nitromethane-promoted alkylation of anilines with arylmethanols

A new application of lithium perchlorate-nitromethane (LPNM) for the formation of aromatic C-N and C-C bonds is introduced. LPNM-promoted reactions of anilines with diarylmethanols selectively generate N-alkylated anilines or mono and double Friedel-Crafts alkylation products under different conditions by changing the reaction time, reaction temperature, and the ratio of the reactants. This method does not require the use of transition metal catalysts to prepare alkylated aniline derivatives.

Ambient Smectic Ordering in Hydrogen-Bonded Liquid Crystal Homologous Series

A homologous series of compounds with an inter-hydrogen bond formed between p-n-alkyloxy benzoic acids (nABA) and alkyl aniline were synthesized and characterized. The mesogenic p-n-alkyloxy benzoic acids (where n represents the alkyloxy carbon number from 3 to 12 except 4 and 6) formed a hydrogen bond with liquid-crystal intermediate 4-dodecyl aniline. The isolated homologous series compounds were analyzed by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (P-NMR), and dielectric studies. The occurrence of an ambient smectic ordering in some of the isolated mesogens was one of the interesting features of these homologous series. The phase diagrams of the p-n-alkyloxy benzoic acids and the present homologous series were computed and compared and it can be mentioned that there exists a correlation between the alkyl chain length and mesogenic phases induced. Further, some of the mesogens exhibit monotropic smectic F and smectic G transitions. The hydrogen bond formation was evinced through FTIR and P-NMR spectral studies. Results of free p-n-alkyloxy benzoic acids and the hydrogen-bonded homologous series are discussed in the light of increment alkyloxy carbon number, mesogenic phases exhibited, and mesogenic thermal range.

ChemInform Abstract: Direct, One‐Pot Reductive Alkylation of Anilines with Functionalized Acetals Mediated by Triethylsilane and TFA. Straightforward Route for Unsymmetrically Substituted Ethylenediamine.

AbstractA new, efficient, and chemoselective method to prepare unsymmetrical ethylenediamines and propylenediamines is reported.

ChemInform Abstract: New Iridium Catalysts for the Efficient Alkylation of Anilines by Alcohols under Mild Conditions.

AbstractNew iridium complexes containing annionic P,N ligands are prepared and shown to promote the selective monoalkylation of amines under mild conditions and with yields superior to those obtained with the original neutral P,N ligand.