6973-40-6Relevant academic research and scientific papers
Copper(I)–creatine complex on magnetic nanoparticles as a green catalyst for N- and O-arylation in deep eutectic solvent
Bagheri, Sepideh,Heydari, Akbar,Pazoki, Farzane,Radfar, Iman
, (2020/01/22)
Immobilization of copper(I) ions on magnetic nanoparticles was performed using surface modification of Fe3O4 with creatine. Fe3O4?creatine-Cu(I) magnetic catalyst was synthesized and applied in C&bond;X cross-coupling reactions with aryl halides in a deep eutectic as a green solvent. The results indicate the Fe3O4?creatine-Cu(I) magnetic nanoparticles showed excellent activity and high stability. In addition, it was revealed that this catalyst can be recycled five times without significant loss in catalytic activity.
Fe3O4@SiO2-copper sucrose xanthate as a green nanocatalyst for N-, O- and S-arylation
Radfar, Iman,Kazemi Miraki, Maryam,Esfandiary, Naghmeh,Ghandi, Leila,Heydari, Akbar
, (2019/01/04)
Formation of C(sp2)–X bonds was carried out using a Fe3O4@SiO2-copper(I) sucrose xanthate nanoparticle catalyst with the aid of the copper(I) xanthate moiety in the catalyst which was prepared from the reaction between sucrose and carbon disulfide through an alkaline medium via the traditional Zeise approach. Various techniques were employed for the characterization of these novel nanoparticles. Three sorts of heteroatoms, N, O and S, successfully underwent heteroatom arylation to produce secondary or tertiary amines, ethers and thioethers, respectively.
Kinetics of the reaction of phenyl picrates with phenoxide ions in water. Concerted or stepwise?
Crampton, Michael R.,Robotham, Ian A.
, p. 1084 - 1089 (2014/01/06)
A kinetic study is reported of the exchange reactions of substituted phenoxide ions with some ring-substituted 2,4,6-trinitrophenyl ethers in water. The βronsted diagrams formed by plotting log k, where k is the second-order rate constant for reaction, ve
Catalytic effects of hydrogen-bond acceptor solvent on nucleophilic aromatic substitution reactions in non-polar aprotic solvent: Reactions of phenyl 2,4,6-trinitrophenyl ether with amines in benzene-acetonitrile mixtures
Banjoko, Olayinka,Babatunde, Ibitola A.
, p. 8035 - 8040 (2007/10/03)
The effect of addition of small amounts of hydrogen-bond acceptor solvent, acetonitrile, to the benzene medium of the reactions of phenyl 2,4,6-trinitrophenyl ether with aniline and cyclohexylamine, respectively have been investigated. The addition produc
The influence of some steric and electron effects on the mechanism of aromatic nucleophilic substitution (SNAr) reactions in nonpolar solvent
Emokpae, Thomas A.,Atasie, Nkechi V.
, p. 744 - 750 (2008/04/18)
Kinetic studies are reported for the reactions with aniline in benzene of a series of X-phenyl 2,4,6-trinitrophenyl ethers [X = H; 2-, 3-, 4-CH 3; 2,4-, or 2,6-(CH3)2] 1a-f, and the results compared with those of the corre
Leaving group effects on the mechanism of aromatic nucleophilic substitution (SnAr) reactions of some phenyl 2,4,6-trinitrophenyl ethers with aniline in acetonitrile
Crampton, Michael R.,Emokpae, Thomas A.,Howard, Judith A.K.,Isanbor, Chukwuemeka,Mondal, Raju
, p. 65 - 70 (2007/10/03)
Kinetic studies are reported for the reactions with aniline in acetonitrile of a series of X-phenyl 2,4,6trinitrophenyl ethers [X = H, 2-, 3-, 4-CH3,2,4-, 2,6-(CH3)2,2-, 3-, 4-NO 2,2,4-, 2,6-(NO2)2]. X-ray crystal structures for X = H, 2,6-(CH3)2 and 2,6-(NO2) 2 are reported and provide evidence for steric crowding around the 1-position of these molecules. Nevertheless, the kinetic data show that increasing substitution does not sterically inhibit nucleophilic attack by aniline and an 'early' transition state is likely. In general, the reactions are base catalysed; interpreted as rate-limiting deprotonation of the zwitterionic intermediates. Only with the dinitro derivatives is an uncatalysed reaction involving intramolecular proton transfer observed and when X = 2,6-(NO2)2 this pathway takes all the reaction flux. Copyright
Kinetic studies of σ-adduct formation and nucleophilic substitution in the reactions of ethyl 2,4,6-trinitrophenyl ether, some phenyl 2,4,6- trinitrophenyl ethers, and phenyl 2,4-dinitronaphthyl ether with aniline in dimethyl sulfoxide
Crampton, Michael R.,Robotham, Ian A.
, p. 627 - 634 (2007/10/03)
The reaction of ethyl 2,4,6-trinitrophenyl ether with aniline in dimethyl sulfoxide containing Dabco occurs in two stages. The first gives 5, the σ-adduct intermediate on the substitution pathway, which has been identified spectroscopically. The second yields 2,4,6-trinitrodiphenylamine, the substitution product. Kinetic studies show that proton transfer is rate limiting both in the formation of the intermediate and in its subsequent acid-catalysed decomposition. Phenoxide is a considerably better leaving group than ethoxide and the substitution reactions of phenyl 2,4,6- trinitrophenyl ethers and phenyl 2,4-dinitronaphthyl ether with aniline in DMSO occur without the accumulation of intermediates. The kinetics indicate both uncatalysed and base-catalysed pathways. The kinetic and equilibrium data for reaction of the ethyl and phenyl ethers are compared with data for σ-adduct formation from 1,3,5-trinitrobenzene and aniline.
Kinetic and equilibrium studies of σ-adduct formation and nucleophilic substitution in the reactions of trinitro-activated benzenes with aliphatic amines in acetonitrile
Crampton, Michael R.,Lord, Simon D.
, p. 369 - 376 (2007/10/03)
Rate and equilibrium constants are reported for reactions in acetonitrile of butylamine, pyrrolidine and piperidine with 1,3,5-trinitrobenzene, 1, and with ethyl 2,4,6-trinitrophenyl ether, 4a, and phenyl 2,4,6-trinitrophenyl ether, 4b. Rapid nucleophilic attack at unsubstituted ring-positions may yield anionic σ-adducts via zwitterionic intermediates, while slower attack at the 1-position of 4a and 4b may lead to substitution to give 2,4,6-trinitroaniline derivatives. Base catalysis in the substitution reaction reflects rate-limiting proton transfer which may be from the zwitterionic intermediates to amine in the case of 4b, or from a substituted ammonium ion to the ethoxy leaving group in the case of 4a. Comparisons with values in DMSO indicate that values of overall equilibrium constants for adduct formation are ca. 104 lower in acetonitrile, while rate constants for proton transfer are ca. 104 higher. These differences may reflect strong hydrogen-bonding between DMSO and -NH+ protons in ammonium ions and in zwitterions. In acetonitrile homoconjugation of substituted ammonium ions with free amine is an important factor.
Reaction pathways for ambident aryloxide O- and C-nucleophiles in SNAr displacement versus Meisenheimer complex formation with picryl halides. Stereoelectronic effects on regioselectivity
Manderville, Richard A.,Dust, Julian M.,Buncel, Erwin
, p. 515 - 528 (2007/10/03)
To probe regioselectivity in Meisenheimer complexation, the reaction of two picryl halides (PiX where X = F, Cl) with a series of aryloxide nucleophiles (phenoxide, 2,4,6-trimethylphenoxide and 2,6-di-t-butylphenoxide) were monitored by 1H NMR spectroscopy in dimethyl sulphoxide at ambient temperature and in acetonitrile-dimethoxyethane(MeCN-DME) at low temperature (-40°C). The reactions of both picryl halides with the ambident (oxygen versus carbon) nucleophile, phenoxide ion (PhO-), and 2,4,6-trimethylphenoxide (mesitoxide, MesO-) leads to clean SNAr displacement of X via the oxygen site of the nucleophile to form the respective aryl picryl ethers, i.e. phenyl picryl ether (3a) and mesityl picryl ether (3b). Meisenheimer complex formation at C-1 or C-3 was not detected in these systems. With 2,6-di-t-butylphenoxide (2,6-DTBPhO-), where oxygen attachment of the aryloxide is precluded by the bulky ortho t-butyl groups, para-carbon attachment was found to occur at C-1 to give picryl 2,6-di-t-butylphenol (3d) in competition with C-attack at C-3 to give the respective carbon-bonded Meisenheimer complexes [X = Cl (4) and X = F (5)]. For both picryl halides, the ratio of 3d, the product of C-1 attack, to the product of C-3 attack, 4 or 5, was roughly 7:1. These findings are considered with regard to the nucleofugality of the halide, X, steric hindrance (F-strain) to attack by the aryloxides at the various positions and stereoelectronic stabilization of C-1 adducts afforded by n → σ* donation.
Mechanism of base catalysis in the reactions of phenyl aryl ethers with aliphatic amines in dimethyl sulfoxide
Chamberlin, Rachel A.,Crampton, Michael R.
, p. 1831 - 1838 (2007/10/02)
The reactions of n-butylamine, pyrrolidine and piperidine with phenyl 2,4,6-trinitrophenyl ether, 3, in DMSO result in the rapid reversible formation of adducts by reaction at the 3-position followed by attack at the 1-position leading to substitution of
