Reaction Of Triphenylphosphine Research Articles

The synthesis of aryl amines enabled by rearrangement and demethylaromatization of cyclohexadienimines.

The rearrangement and demethylaromatization of cyclohexadienimines (namely cyclohexadienone imines) were investigated in detail under metal-free conditions. Treating 4-aryl-4-methylcyclohexadienimines with acyl chloride at 100 °C in dichloromethane led to the smooth formation of m-arylaniline derivatives in good to excellent yields, in which [1,2]-migration of the aryl group at C-4 occurred exclusively. The demethylaromatization of 4-aryl-4-methylcyclohexadienimines mediated by iodotriphenylphosphonium iodide (in situ prepared via the reaction of triphenylphosphine with iodine) in toluene at 100 °C proceeded well, generating p-arylanilines in moderate to good yields. An efficient and alternative method for the synthesis of polysubstituted aryl amines, especially m-arylaniline derivatives which are otherwise difficult to synthesize through traditional methods, was developed.

Ester-stabilized phosphorus ylides as protonophores on bilayer lipid membranes, mitochondria and chloroplasts

Triphenylphosphonium ylides are commonly used as key intermediates in the Wittig reaction. Based on the known acidities of stabilized ylide precursors, we proposed that a methylene group adjacent to phosphorus in these compounds can ensure proton shuttling across lipid membranes. Here, we synthesized (decyloxycarbonylmethyl)triphenylphosphonium bromide (CMTPP-C10) by reaction of triphenylphosphine with decyl bromoacetate. This phosphonium salt precursor of the ester-stabilized phosphorus ylide along with its octyl (CMTPP-C8) and dodecyl (CMTPP-C12) analogues was found to be a carrier of protons in mitochondrial, chloroplast and artificial lipid membranes, suggesting that it can reversibly release hydrogen ions and diffuse through the membranes in both zwitterionic (ylide) and cationic forms. The CMTPP-C10-mediated electrical current across planar bilayer lipid membranes exhibited pronounced proton selectivity. Similar to conventional protonophores, known to uncouple electron transport and ATP synthesis, CMTPP-Cn (n = 8, 10, 12) stimulated mitochondrial respiration, while decreasing membrane potential, at micromolar concentrations, thereby showing the classical uncoupling activity in mitochondria. CMTPP-C12 also caused dissipation of transmembrane pH gradient on chloroplast membranes. Importantly, CMTPP-C10 exhibited substantially lower toxicity in cell culture, than C12TPP. Thus, we report the finding of a new class of ylide-type protonophores, which is of substantial interest due to promising therapeutic properties of uncouplers.

Iminophosphoranes: Synthesis, evolution of synthesis by 31P-NMR, DFT calculations and antioxidant activity

New mono-iminophosphoranes and new bis-iminophosphoranes 3 were prepared by reaction of triphenylphosphine or tri-alkyl phosphite and azides 1. In order to reduce the reaction time and detect the phosphazides intermediates 2, the reactions of synthesis of iminophosphoranes 3 were evaluated by 31P-NMR spectroscopy. Two phosphazides intermediates 2 in the Z/E form were detected. Density Functional Theory (DFT) calculations were performed at B3LYP/6-311++G** and M062X/def2TZVP to determine the relative stability of Z/E intermediates. Antioxidant activities of iminophosphoranes 3 were evaluated by a 1,1-diphenyl-2-picryl hydrazyl (DPPH) test. The compounds were characterized on the basis of IR, NMR spectroscopy (1H, 13C and 31P) and by HRMS.

New square-planar nickel(II)-triphenylphosphine complexes containing ONS donor ligands: Synthesis, characterization, electrochemical and antioxidant properties

Five new mixed ligand nickel(II) complexes with the general formula [Ni(L)(PPh3)], [C1–C5], were prepared from the reaction of triphenylphosphine (PPh3) with ONS donor ligands (L) [where R = Η (L1); 4-OCH3 (L2); 4-OCH2(CH2)6CH3 (L3); 4-OCH3, 4′-CH3 (L4) and 4-OCH2CHCH2 (L5)] derived from 2-hydroxybenzophenones and thiocarbohydrazide. The structures of the complexes were characterized by elemental analysis, IR, 1H and 31P NMR spectroscopy, conductivity measurements. The crystal structures of ligand (L2) and complex (C2) were determined by single crystal X-ray diffraction method. The ligand is coordinated to the nickel core through the phenolate oxygen, azomethine nitrogen and sulfur atoms, while the fourth coordination site is occupied by the P atom of a triphenylphosphine ligand. X-ray analysis indicated distorted square-planar structure for the complex C2. Electrochemical behaviors of thiocarbohydrazone ligands (L1-L5) and their nickel(II) complexes (C1–C5) were studied and effects of the type of substituents were compared. All ligands illustrated two irreversible reductions and one irreversible oxidation. Complexing of the ligands with Ni(III) ion considerably influenced their redox behaviors. Electron transfer process of the complexes get easier and became more reversible when compared with those of the corresponding ligands. Moreover, Ni(II) complexes illustrated NiII/NiI and NiII/NiIII processes in addition to the ligand-based electron transfer reactions. In-situ spectroelectrochemical responses of the ligands considerably changed after formation of Ni(II) complexes. Total antioxidant capacity and free radical scavenging activity of the compounds have been tested using CUPRAC and DPPH methods, respectively. The results of Ni(II) complexes were compared with a standard antioxidant compound.

Electrochemical synthesis of a new phosphonium betaine. Kinetic evaluation and antibacterial susceptibility

Cyclic voltammetry, controlled-potential coulometry, chronoamperometry, chronocoulometry and chronopotentiometry methods were used for the electrochemical study of 1-acetyl-4-(4-hydroxyphenyl)piperazine (APIP) in the presence of triphenylphosphine (TPP) as a nucleophile. The data show that electrochemically generated APIPox can serve as a Michael acceptor for nucleophilic attack by TPP to yield a new phosphonium betaine (APTP). In this work, we prepared a new product in good yield and purity by reaction of TPP with APIPox in an undivided cell equipped with carbon anode. Based on an EC mechanism, the observed homogeneous rate constant (kobs) of the Michael addition reaction of APIPox with TPP were estimated by comparing the experimental cyclic voltammograms with the digital simulated results. Furthermore, electrochemical oxidation of APIP has been studied both experimentally and theoretically to provide insight into the influence of natural charge and thermodynamic stability parameters on the type of chemical reaction which follows APIPox. In addition, the synthesized compound was evaluated for in vitro antibacterial.

Metal-Free Synthesis of Aryltriphenylphosphonium Bromides by the Reaction of Triphenylphosphine with Aryl Bromides in Refluxing Phenol.

A metal-free synthesis of aryltriphenylphosphonium bromides by the reaction of triphenylphosphine with aryl bromides in refluxing phenol is developed. This reaction tolerates hydroxymethyl, hydroxyphenyl, and carboxyl groups in aryl bromides, allowing to synthesize multifunctional aryltriphenylphosphonium bromides, from which facile access to multifunctional aryldiphenylphosphines and their oxides by hydrolysis and subsequent reduction is exemplified. A two-step addition–elimination mechanism, with the elimination step being a fast step, is also proposed.

Coordination of arenes and phosphines by charge separated alkaline earth cations.

Generation of β-diketiminato group 2 cations, [(MeBDI)Ae]+ and [(t-BuBDI)Ae]+ (MeBDI = HC{(Me)CN-2,6-i-Pr2C6H3}2; t-BuBDI = HC{(t-Bu)CN-2,6-i-Pr2C6H3}2; Ae = Mg or Ca), in conjunction with the weakly coordinating anion, [Al{OC(CF3)3}4]-, allows the characterisation of charge separated alkaline earth η6-π adducts to toluene or benzene when crystallised from the arene solvents. Addition of 1,4-difluorobenzene to [(MeBDI)Mg]+ results in the isolation of [(MeBDI)Mg(1,4-F2C6H4)3]+ in which the fluorobenzene molecules coordinate via κ1-F-M interactions. Although DFT analysis indicates that the polyhapto arene binding to Mg is effectively electrostatic in origin, the interactions with Ca (Sr and Ba) are observed to invoke small but significant π overlap of the arene HOMOs with the alkaline earth valence nd orbitals. Reaction of triphenylphosphine with [(MeBDI)Mg]+ and [(t-BuBDI)Mg]+ in toluene solvent allows the isolation of the respective terminally coordinated magnesium-phosphine adducts. The resultant Mg-P bond lengths [2.5972(13), 2.6805(12) Å] are comparable to those previously observed in magnesium derivatives of terminal but formally anionic phosphide ligands, while the effectively electrostatic nature of the bonding is supported by DFT calculations.

Crystal structure of triphenylphosphonium-meth-yl-enetrifluoroborate.

The title compound, C19H17BF3P {alternative name: triphen-yl[(tri-fluoro-boran-yl)meth-yl]phosphanium}, was formed by the reaction of tri-phenyl-phosphine with potassium iodo-methyl-tri-fluoro-borate. The mol-ecule features a nearly staggered conformation along the P-C bond and a less than staggered conformation along the C-B bond. In the crystal, weak C-H⋯F hydrogen bonds between the meta-phenyl C-H groups and the tri-fluoro-borate B-F groups form chains of R22(16) rings along [100]. These chains are are further stabilized by weak C-H⋯π inter-actions. A weak intra-molecular C-H⋯F hydrogen bond is also observed.

“β-Cyclodextrin Nanoreactor” Catalyzed Synthesis of Coumarin Derivatives from In-Situ Generated Stabilized Phosphorus Ylides in Water

GRAPHICAL ABSTRACT

ChemInform Abstract: Synthesis of (Triphenylphosphoranylidene)spiro[cyclopentene‐1,3′‐indole]s by a Three‐Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylates, and 3‐(Aroylmethylene)‐1,3‐dihydro‐2H‐indol‐2‐ones.

ChemInform Abstract: Synthesis of (Triphenylphosphoranylidene)spiro[cyclopentene‐1,3′‐indole]s by a Three‐Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylates, and 3‐(Aroylmethylene)‐1,3‐dihydro‐2H‐indol‐2‐ones.

Phosphonium modified clay/polyimide nanocomposites

In this study, octyltriphenylphosphonium bromide [OTPP-Br] was prepared from the reaction of triphenylphosphine and 1 -bromooctane. The modification of clay was done by ion exchange reaction using OTPP-Br in water medium. Poly(amic acid) was prepared from the reaction of 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-Oxydianiline (ODA). Polyimide(PI)/clay hybrids were prepared by blending of poly(amic acid) and organically modified clay as a type of layered clays. The morphology of the Polyimide/ phosphonium modified clay hybrids was characterized by scanning electron microscopy (SEM). Chemical structures of polyimide and Polyimide/ phosphonium modified clay hybrids were characterized by FTIR. SEM and FTIR results showed that the Polyimide/ phosphonium modified clay hybrids were successfully prepared. Thermal properties of the Polyimide/ phosphonium modified clay hybrids were characterized by thermogravimetric analysis (TGA).

Effect of Anchimeric Assistance in the Reaction of Triphenylphosphine with α,β‐Unsaturated Carboxylic Acids

ABSTRACTQuaternization of triphenylphosphine with maleic and cis‐aconitic acids is strongly accelerated by participation of the cis‐carboxyl group in stabilization of the phosphonium zwitterion intermediate by intramolecular hydrogen bonding, in spite of steric hindrance by the acid's reaction center. A similar effect for trans‐isomeric acids is not observed, which can be rationalized on the basis of spatial structures of the generated zwitterions, implying an electrostatic interaction between the phosphonium center and carbonyl oxygen atom. The effect of anchimeric assistance decreases when the intramolecular hydrogen bonding disfavors attack of the phosphine on the sterically less hindered carbon atom of the C=C bond, as observed for cis‐aconitic acid.

Three-Component Reaction of Triphenylphosphine, Acetylenic Esters, and 6-Aminouracil or 6-Amino-N,N′-dimethyluracil

Protonation of the reactive 1:1 intermediate produced in the reaction of acetylenic esters and triphenylphosphine by 6-aminouracil or 6-amino-N,N′-dimethyluracil leads to vinylphosphonium salts, which undergo Michael addition with the conjugate base of the NH acid to produce highly fanctionalized, salt-free phosphorus ylides in excellent yields.

Special features of the interaction of pyridine and quinoline derivatives, and related compounds with triphenylphosphine

Using pyridine, quinoline, and related compounds as examples, it has been shown that their interaction with triphenylphosphine occurs via different pathways. Reaction of triphenylphosphine with N-vinylisonicotinic acid chloride leads to the mixture of 1,2-bis(triphenylphosphoniumchlorido)ethane and 4-carboxy-2-(triphenylphosphoniumchloridoethyl)pyridine. In the case of α-(N-2-carboxyquinolinylbromido)-β-bromopropionic acid, the reaction with triphenylphosphine proceeds via phosphine attack on the oxygen atom with elimination of quinaldinic acid, and subsequent nucleophilic substitution with the formation of 3-(triphenylphosphoniumbromido) propionic acid bromide.

ChemInform Abstract: Three‐Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylate, and 2‐Aminothiazole or 2‐Aminobenzothiazole in the Presence of Arylglyoxals: An Efficient One‐Pot Synthesis of Highly Functionalized Pyrroles.

Abstract A new and efficient one-pot synthesis of polysubstituted pyrrole derivatives by three-component reaction of dialkyl acetylenedicarboxylates, triphenylphosphine, 2-aminothiazole or 2-aminobenzothiazole in the presence of arylglyoxals is described. The reactions were performed in dichloromethane at room temperature and neutral conditions and afforded good yields of products.

Synthesis of a New Class of Highly Functionalized Phosphorus Ylides Containing Heterocyclic Compounds

AbstractThe zwitterionic intermediate generated from the reaction of triphenylphosphine with electron deficient acetylenic compounds was trapped by various NH acids. The synthesis resulted in a new class of highly functionalized heterocyclic compounds. Some of the reactions produced E and Z isomers. And the stability and transformation of them were studied by dynamic 1H NMR and density functional theory (DFT) calculations.

One–Pot Synthesis of β,γ-Unsaturated γ-Lactone Phosphorus Yildes using 2-Nitro Trans-Cinnamaldehyde and Acetylenic Esters in the Presence of Triphenylphosphine

Three-component reaction of triphenylphosphine and 2-nitro trans-cinnamaldehyde with dialkyl acetylenedicarboxylate leads to β,γ-unsaturated γ-lactone phosphorus ylides in moderate yields. The reactions of 2-nitro trans-cinnamaldehyde with alkyl propiolates in the presence of triphenylphosphine produce 2H-pyran derivatives in moderate yields without the formation of any γ-lactone derivatives.

Synthesis and Dynamic NMR Study of New Stable Ylides Derived from the Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylates, and 5-ACYL Meldrum’s Acid

Triphenylphosphine and dialkyl acetylenedicarboxylate react smoothly in the presence of 5-acyl Meldrum's acid in dichloromethane at room temperature and lead to synthesis of new stable ylide derivatives of dimethyl (5-acetyl-2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-yl)-3-(triphenyl-λ5-phosphanylidene) succinate. Dynamic NMR study results of rotamers are reported and compared with the previous-related reports.

ChemInform Abstract: Three‐Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylates, and Heterocyclic Rings and the Related Iminophosphoranes.

AbstractThe title reaction including diester (III) or its diethyl analogue affords phosphorus ylides of type (IV) which exist as mixtures of rotamers.

Three-Component Reaction of Triphenylphosphine, Dialkyl Acetylenedicarboxylate, and 2-Aminothiazole or 2-Aminobenzothiazole in the Presence of Arylglyoxals: An Efficient One-Pot Synthesis of Highly Functionalized Pyrroles

A new and efficient one-pot synthesis of polysubstituted pyrrole derivatives by three-component reaction of dialkyl acetylenedicarboxylates, triphenylphosphine, 2-aminothiazole or 2-aminobenzothiazole in the presence of arylglyoxals is described. The reactions were performed in dichloromethane at room temperature and neutral conditions and afforded good yields of products.