Diethyl Phosphonate Research Articles

Ferromagnetic exchange coupling in phosphonato-bridged dinuclear copper(II) compound with monoethyl (pyridyn-2-ylmethyl)phosphonate ligand (2-mpmpe): Cu 2(2-mpmpe) 2(H 2O) 2(NO 3) 2

The interaction of diethyl (pyridyn-2-ylmethyl)phosphonate (2-pmpe) with Cu(NO 3) 2 · 6H 2O leads to a partial hydrolysis of the starting ligand and formation of the compound of the formula Cu 2(2-mpmpe) 2(H 2O) 2(NO 3) 2, where 2-mpmpe = monoethyl (pyridyn-2-ylmethyl)phosphonate. The crystal and molecular structure of a copper(II) compound was determined by single X-ray diffraction method. Its structure consists of five-coordinated in distorted square planar geometry (CuNO 4 chromophore) copper(II) ions doubly bridged by OPO from phosphonate. The Cu⋯Cu distance is 4.69 Å. The crystal packing is determined by the interdinuclear hydrogen bond system, which leads to a three-dimensional (3D) H-bonds network. The compound was characterized by infrared, ligand field, EPR spectroscopy, and magnetic studies. The magnetic properties of the title compound investigated over the 1.8–300 K, revealed the occurrence of a weak ferromagnetic coupling through phosphonate bridge ( J = 1.86 cm −1) and interdimer superexchange coupling through H-bond network ( zJ′ = −0.17 cm −1). Spectroscopic and magnetic properties are presented in the light of crystal structure.

Co(II)-promoted transformation of diethyl(quinolin-2-ylmethyl)phosphonate to quinoline-2-carboxylate (2-qca): Synthetic, structural and magnetic studies of [Co(2-qca) 2(EtOH) 2

The interaction of the diethyl(quinolin-2-ylmethyl)phosphonate (2-qmpe) ligand with CoCl 2 · 2H 2O unexpectedly leads to the formation of a compound with the formula [Co(2-qca) 2(EtOH) 2] (2-qca = quinoline-2-carboxylate). This compound is a product of the oxidative cleavage of the C–P bond in 2-qmpe and the formation of the 2-qca ligand. The title compound was characterized by infrared, ligand field, EPR spectroscopy and low temperature magnetic (1.8–300 K) studies. Particularly, the crystal and molecular structures were determined by the X-ray diffraction. The CoN 2O 4 chromophore shows an elongated octahedron geometry, resulting from the two didentate N,O-bonded chelate ligands and two ethanol molecules – quinolil nitrogen atoms are located in axial positions and oxygen atoms are positioned in the basal plane. The crystal packing is due to hydrogen bonds and π–π stacking interactions, which give rise to a three-dimensional (3D) polymeric network. The magnetic properties reflect the molecular character of the compound, with a very weak magnetic exchange interaction. The moments are enhanced due to an important orbital contribution via spin–orbit coupling.

Synthesis of diethyl 2-thioxo-1,2,3,4-tetrahydroand hexahydropyrimidine-5-phosphonates

The reaction of sodium enolate of diethyl (2-oxoprop-1-yl)phosphonate with N-(1-tosylprop-1-yl)thiourea results in the stereoselective formation of diethyl (4R*,5R*,6R*)-6-ethyl-4-hydroxy-4-methyl-2-thioxohexahydropyrimidine-5-phosphonate, which is transformed into diethyl 4-ethyl-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-phosphonate and diethyl (4R*,5S*,6R*)-4-ethyl-6-methyl-2-thioxohexahydropyrimidine-5-phosphonate by acid-catalysed dehydration and stereoselective reduction with NaBH4–CF3COOH, respectively.

Synthesis and characterization of phosphonic acid-substituted porphyrazines

Porphyrazines with phosphonic acid groups on the peripheral positions have been prepared by the cyclotetramerization of 1,2-bis{2-(diethyl phosphonate)ethylthio} maleonitrile and followed by the cleavage of the phosphonate esters with TMSBr.

Synthesis of lipophilic 2‐oxoamides based on γ‐aminobutyric and δ‐aminovaleric analogues and their activity against phospholipase A2

A variety of lipophilic 2-oxoamides based on gamma-aminobutyric and delta-aminovaleric analogues were synthesized. 2-oxoamides containing a tetrazole, a thioethyl or a thioacetyl group are weak inhibitors of GIVA cPLA(2), while derivatives containing a methyl tetrazole, a diethyl phosphonate or a thioethyl group are weak inhibitors of GV sPLA(2).

Temperature Effects on Stereocontrol in the Horner−Wadsworth−Emmons Condensation of α-Phosphono Lactones

The Horner-Wadsworth-Emmons condensation of some alpha-phosphono lactones has been examined for conditions that impact product stereochemistry. The temperature employed to quench the reaction was found to be a major factor. For example, after the diethyl phosphonate derivative of gamma-butyrolactone was treated with potassium hexamethyldisilazane, 18-crown-6, and propionaldehyde at -78 degrees C in THF, an aliquot transferred to a flask at approximately 30 degrees C gave almost exclusively the Z-olefin product, while one allowed to warm to room temperature over several hours greatly favored the E-olefin.

Flame retardance and shrinkage reduction of polystyrene modified with acrylate-containing phosphorus and crosslinkable spiro-orthoester moieties

Styrene was radically copolymerized with a spiro-orthoester with an acrylate group (SOE-AC), and terpolymerized with SOE-AC and diethyl(methacryloyloxymethyl)phosphonate (DEMMP). This was done for several different feed ratios, to obtain polymers with spiro-orthoester moieties in the side chain. These polymers were then crosslinked with ytterbium triflate, as cationic initiator, via the double ring-opening polymerization. The thermal stability and fire retardant properties of these materials were evaluated by TGA and LOI. The DEMMP-containing polymers give materials which were significantly more flame retardant than the nonphosphorus-containing materials, as indicated by the LOI measurements. The volume changes measured upon crosslinking of the polymers were evaluated by density measurements with a gas pycnometer. In all the cases, expansion was observed. This indicates that SOE-AC is an effective monomer for crosslinkable polymers without volume changes.

Spectroscopic studies of lanthanides complexes with diethyl benzylphosphonate and diethylphosphonoacetic acid

Abstract Spectroscopic properties of Ln(III) complexes with diethyl benzylphosphonate (PhCH 2 P(O)(EtO) 2 ) and diethyl (carboxymethyl)phosphonate ((EtO) 2 P(O)CH 2 COOH) were investigated using absorption and luminescence spectroscopy. Absorption spectra of organophosphorus ligand with Nd(III) were measured in acetonitril solution and oscillator strength values and Judd–Ofelt parameters were calculated. Excitation and luminescence spectra of Eu(III) and Tb(III) ions with diethyl benzylphosphonate were measured. Energy transfer was observed from PhCH 2 P(O)(EtO) 2 ligand to Tb(III) ion and quantum yield ( Φ f = 0.04) was determined. The Eu(III) selective excitation spectra of 5 D 0 ← 7 F 0 band in Eu 3+ /PhCH 2 P(O)(EtO) 2 and Eu 3+ /(EtO) 2 P(O)CH 2 COOH system were recorded in order to evaluate the number of species forms observed in studied systems and luminescence lifetimes of Eu(III) ion have been determined from those spectra.The La(III) and Pr(III) complexes with the studied ligands were synthesized and their structures were confirmed by elemental analysis, IR spectra and also 13 C and 31 P-NMR.

Synthetic and Mechanistic Investigations on the Rearrangement of 2,3‐Unsaturated 1,4‐Bis(alkylidene)carbenes to Enediynes

AbstractThe synthesis of 3,4‐ene‐1,5‐diynes, the key structural moiety present in several naturally occurring antitumor antibiotics, from 1,2‐enedialdehydes under two different experimental conditions is reported. One method involves the dibromomethylenation of dialdehydes under Corey–Fuchs conditions (CBr4, Ph3P, and Zn) and treatment of the resulting tetrabromides with nBuLi or LDA to afford enediynes. The second method involves a base‐mediated reaction of enedialdehydes with diethyl (1‐diazo‐2‐oxopropyl)phosphonate (Bestmann–Ohira reagent) and subsequent transformation of the bis(diazo) compounds generated in situ to enediynes. While the transformation of bis(diazo) compounds to enediynes could take place exclusively through alkylidenecarbenes, generated in situ by geminal elimination of N2, an alternative pathway, involving the vicinal elimination of HBr to afford an intermediate bromoalkyne and its subsequent metal‐halogen exchange and protonation during workup, exists for the bis(dibromoalkylidenes). However, our deuterium‐labeling experiments with a model substrate, deuterated p‐methoxybenzylidene dibromide, established the predominance of the alkylidenecarbenes, generated in situ by metal‐halogen exchange and elimination, for this substrate and, by analogy, for the tetrabromides as well. The scope of this novel methodology was extended to the synthesis of various heteroatom‐based (S, Se, and P) enediynes by quenching the acetylides with suitable electrophiles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Lanthanide complexes with diethyl(2-oxopropyl) phosphonate and diethyl(2-oxo-2-phenylethyl) phosphonate ligands

Abstract Ln 3+ complexes with the phosphonate ligands: diethyl(2-oxopropyl) phosphonate [CH 3 C(O)CH 2 P(O)(OC 2 H 5 ) 2 ] (OPP) and diethyl (2-oxo-2-phenylethyl) phosphonate [C 6 H 5 C(O)CH 2 P(O)(OC 2 H 5 ) 2 ] (DEPP) were synthesized and characterized. Complexation studies and spectral characterizations are performed. Based on the Nd 3+ absorption spectra, using computer-assisted target factor analysis, the stability constants of Nd-OPP complexes in solution were determined to be log β 11 = 2.8 ± 0.4 and log β 12 = 5.0 ± 0.7. Luminescence intensities, lifetimes, τ , and quantum yields, Φ , of the Eu 3+ and Tb 3+ ions in the complexes were measured. The most intense luminescence was observed in the case of the Tb/DEPP system. Emission enhancements were observed for Tb 3+ and Eu 3+ complexes in acetonitrile solutions, which occurred as a result of sensitized luminescence. These observed luminescence intensities were over two orders of magnitude larger than those for the uncomplexed Ln(III) ions. The complexes of Ln/L/NO 3 , obtained in oil forms from ethanol at room temperature, were characterized by elemental analysis, IR spectroscopy, and luminescence lifetime measurements. The composition of the complexes studied is suggested to be LnL 2 (NO 3 ) 3 , with monodentate coordination by the phosphoryl group.

A new bisphosphonate-containing 99mTc(I) tricarbonyl complex potentially useful as bone-seeking agent: synthesis and biological evaluation

Aiming to develop new bone-seeking radiotracers based on the organometallic core fac-[(99m)Tc(CO)(3)](+) with improved radiochemical and biological properties, we have prepared new conjugates with phosphonate pendant groups. The conjugates comprise a chelating unit for metal coordination, which corresponds to a pyrazolyl-containing backbone (pz) with a N,N,N donor-atom set, and a pendant diethyl phosphonate (pz-MPOEt), phosphonic acid (pz-MPOH) or a bisphosphonic acid (pz-BPOH) group for bone targeting. Reactions of the conjugates with the precursor [(99m)Tc(H(2)O)(3)(CO)(3)](+) yielded (mote than 95%) the single and well-defined radioactive species [(99m)Tc(CO)(3)(kappa(3)-pz-MPOEt)](+) (1a), [(99m)Tc(CO)(3)(kappa(3)-pz-MPOH](+) (2a) and [(99m)Tc(CO)(3)(kappa(3)-pz-BPOH)](+) (3a), which were characterized by reversed-phase high-performance liquid chromatography . The corresponding Re surrogates (1-3), characterized by the usual analytical techniques, including X-ray diffraction analysis in the case of 1, allowed for macroscopic identification of the radioactive conjugates. These radioactive complexes revealed high stability both in vitro (phosphate-buffered saline solution and human plasma) and in vivo, without any measurable decomposition. Biodistribution studies of the complexes in mice indicated a fast rate of blood clearance and high rate of total radioactivity excretion, occurring primarily through the renal-urinary pathway in the case of complex 3a. Despite presenting moderate bone uptake (3.04 +/- 0.47% injected dose per gram of organ, 4 h after injection), the high stability presented by 3a and its adequate in vivo pharmacokinetics encourages the search for new ligands with the same chelating unit and different bisphosphonic acid pendant arms.

The Mild Synthesis of Oxime Phosphates by Atherton–Todd Reaction

The oximes (1a–i) on reaction with diethyl phosphonates (2) in the presence of triethylamine using chlorocarbons as solvents mildly provide oxime phosphates (3a–i) in good yields and have no the Beckmann rearrangement.

Convenient synthesis of β-allenic α-difluoromethylenephosphonic acid monoesters: Potential synthons for cyclic phosphate mimics

β-Allenic α-difluoromethylenephosphonic acid monoesters were prepared under mild conditions for the first time by hydrolyzing the corresponding diethyl phosphonates in aqueous sodium hydroxide solution.

Phosphorylated copolymers containing pendant, crosslinkable spiro orthoester moieties

AbstractThe synthesis of a novel spiro orthoester containing monomer, 1,4,6‐trioxaspiro[4.4]‐2‐nonylmethyl acrylate, is presented. This monomer was polymerized via a free‐radical system to yield the homopolymer and a series of copolymers with phosphorus‐containing comonomers. Diethyl vinyl phosphonate, allyldiphenylphosphine oxide, and diethyl(methacryoyoxymethyl)phosphonate were used in various feed ratios to produce copolymers with different phosphorous concentrations containing crosslinkable spiro orthoester side‐chain units. The crosslinking of the polymers was performed cationically with ytterbium triflate, and in all cases, the expansion of the polymer was observed. Moreover, the incorporation of phosphorus into the copolymers increased the limiting oxygen indices, regardless of the percentage of phosphorus used. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6728–6737, 2006

Two polymorphs of potassium trichloro[diethyl (methylsulfinylmethyl)phosphonate-κS]platinum(II) withZ′ = 1 and 3 in the space groupP212121

Two new polymorphs of the title compound, K[PtCl(3)(C(6)H(15)O(4)PS)], already known in the monoclinic form, were obtained by crystallization from acetone-n-pentane solutions of different composition. Both polymorphs are orthorhombic in the space group P2(1)2(1)2(1), with Z' = 1 (solvent ratio 1:4) and 3 (solvent ratio 1:9). In both polymorphs, electrostatic interactions link K(+) cations and [PtCl(3)(SMP)](-) anions [SMP is diethyl (methylsulfinylmethyl)phosphonate] in infinite chains, while adjacent chains are held together by weak C-H...Cl and C-H...O hydrogen-bond interactions.

Flame retardancy of cotton textiles by plasma-induced graft-polymerization (PIGP)

The permanent fire proofing of textiles of natural origin such as cotton is still challenging because only a surface treatment can be applied. Moreover, to be resistant to washing or harsh weather conditions the flame retardant must be fixed strongly to the surface, most efficiently achieved via covalent bonds. For that purpose, the simultaneous grafting and polymerization of fire retardant monomers on cotton fabric induced by argon plasma have been investigated with four acrylate monomers containing phosphorus, diethyl(acryloyloxyethyl)phosphate (DEAEP), diethyl-2-(methacryloyloxyethyl)phosphate (DEMEP), diethyl(acryloyloxymethyl)phosphonate (DEAMP) and dimethyl(acryloyloxymethyl)phosphonate (DMAMP), which are known to be effective for this application. We also report the synthesis and the plasma-induced graft-polymerization (PIGP) of two new phosphoramidate monomers, diethyl(acryloyloxyethyl)phosphoramidate (DEAEPN) and acryloyloxy-1,3-bis(diethylphosphoramidate)propan (BisDEAEPN) on cotton fabrics. Their flame retardant effect was compared with the previously used acrylate phosphate and phosphonate monomers. DEAEPN and BisDEAEPN exhibit the highest LOI values (28.5 and 29.5 respectively). The good flame retardant properties of these phosphoramidate monomers are attributed to the presence of nitrogen which causes a synergistic enhancement in the efficiency of phosphorus-based flame retardants. The grafting and the polymerization processes taking place on the surface of the cotton textile were followed by weighing measurements, IR (ATR) spectroscopy and SEM. The fire retardant character of the treated fabrics was investigated by thermogravimetric analyses and LOI measurements. The durability of the treatment was investigated by using the accelerated method of laundering proposed by McSherry et al.

The acetylcholinesterase inhibitor, Donepezil, regulates a Th2 bias in Alzheimer's disease patients

The increased pro-inflammatory cytokine production was previously observed in Alzheimer's disease (AD). We sought to explore whether acetylcholinesterase inhibitor (AChEI) therapy ameliorates clinical symptoms in AD through down-regulation of inflammation. Expression and release of monocyte chemotactic protein-1 (MCP-1), a positive regulator of Th2 differentiation, and interleukin (IL)-4, an anti-inflammatory cytokine from peripheral blood mononuclear cells (PBMC) in AD patients, were investigated. PBMC were purified from AD patients at time of enrolment (T0) and after 1 month of treatment with AChEI (T1) and from healthy controls (HC). Supernatants were analyzed for cytokine levels by ELISA methods. mRNA expression were determined by RT–PCR. Expression and production of MCP-1 and IL-4 were significantly increased in AD subjects under therapy with the AChEI Donepezil, compared to the same AD patients at time of enrolment ( P < 0.001). Our data suggest another possible explanation for the ability of Donepezil [diethyl(3,5-di-ter-butyl-4-hydroxybenzyl)phosphonate] to delay the progression of AD; in fact, Donepezil may modulate MCP-1 and IL-4 production, which may reflect a general shift towards type Th0/Th2 cytokines which could be protective in AD disease. The different amounts of MCP-1 and IL-4 observed might reflect the different states of activation and/or responsiveness of PBMC, that in AD patients could be kept in an activated state by pro-inflammatory cytokines.

One‐Pot Synthesis of Trifluoromethylated 4‐Cyanoalka‐1,4‐dienes with Predominant Z‐Selectivity

AbstractFor Abstract see ChemInform Abstract in Full Text.

Aryl (ferrocenyl)-capped ethenylazaferrocenes: synthesis, structure and electrochemistry

The Horner–Wadsworth–Emmons reaction of 2,5-dimethylazaferrocene-1′-carbaldehyde with diethyl benzylphosphonate, diethyl p-methoxybenzylphosphonate and diethyl (ferrocenylmethyl)phosphonate afforded (E)-1-(2,5-dimethylazaferrocen-1′-yl)-2-phenylethene (2a), (E)-1-(2,5-dimethylazaferrocen-1′-yl)-2-(p-methoxyphenyl)ethene (2b) and (E)-1-(2,5-dimethylazaferrocen-1′-yl)-2-ferrocenylethene (2c), respectively. Cyclic voltammetry showed significant difference in the electrochemical behaviour of these compounds in comparison to their ferrocenyl counterparts. The styryl group, which is an electron-withdrawing group in the ferrocenyl compound, displays a reverse effect in the azaferrocenyl complex 2a. Introduction of the p-methoxystyryl group to 2,5-dimethylazaferrocene brings about a cathodic shift of the redox potential of 370 mV, whereas for the ferrocenyl analog the shift is only 60 mV. Compound 2c shows two redox waves due to two non-equivalent metallocenyl moieties, but there is only weak electronic coupling between redox centres. The W(CO)5-complex of 2c (4) was synthesised and its structure determined by X-ray diffraction.

Linear and cyclic aminomethanephosphonic acid esters derived from benzaldehyde derivatives, 3-aminopropanol, and diethyl phosphite

A series of four diethyl {[(3-hydroxy- propyl)amino](aryl)methyl}phosphonates have been prepared and characterized. In one case, the phosphonate was transformed to a seven-membered 1,4,2- oxazaphosphepane heterocycle through a one-pot intramolecular esterification. The analogous reaction with formaldehyde gave the six-membered diethyl (1,3-oxazinan-3-ylmethyl)phosphonate, which could be transformed in a posterior reaction to the corresponding aminomethanephosphonic acid. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:75–80, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20178