Electroreduction of tetra-coordinate phosphonium derivatives; one-pot transformation of triphenylphosphine oxide into triphenylphosphine

Electroreduction of triphenylphosphine dichloride in acetonitrile was performed successfully in an undivided cell fitted with an aluminium sacrificial anode and a platinum cathode, wherein Al³⁺, which was electrogenerated at the anode would react as a Lewis acid with triphenylphosphine dichloride to afford tetra-coordinate chlorotriphenylphosphonium species and subsequent two-electron reduction at the cathode would give triphenylphosphine. One-pot transformation of triphenylphosphine oxide to triphenylphosphine was achieved successfully by the treatment of triphenylphosphine oxide with oxalyl chloride and subsequent electroreduction. In a similar manner, some tetra-coordinate triphenylphosphonium species derived from triphenylphosphine oxide were reduced electrochemically to triphenylphosphine in moderate yields.     

Polycondensation of aromatic dicarboxylic acids and bisphenols with a new tosyl chloride/triphenylphosphine oxide/pyridine condensing agent

A new condensing agent comprised of tosyl chloride (TsCl) and triphenylphosphine oxide (TPPO) in pyridine was very effective for the preparation of polyesters of aromatic dicarboxylic acids and bisphenols with higher molecular weight than those obtained from TsCl/dimethylformamide in pyridine. Among the phosphorus compounds examined TPPO was most effective, and the reaction using half an equivalent with respect to the carboxyl groups yielded the most favorable results at temperatures of more than 100°C.     

一锅法合成二硫醚的简便制备过程研究

双（三氯甲基）碳酸酯与三苯基膦反应生成的二氯三苯基膦在三乙胺存在下与 硫酚（醇）反应，合成了一系列收率良好的二硫醚化合物。该过程采用“一锅法” ，操作方便，后处理简单，条件温和，提供了一条合成二硫醚的重要路线。     

Synthesis of some Indanones having Nitrogen-containing Substituents

The title compounds have been synthesized by a Friedel-Crafts acylation-alkylation between aromatic ethers and α,β-unsaturated carboxylic acids (or esters) having nitrogen-containing substituents. Polyphosphoric acid was used as condensing agent.     

Electroreduction of triphenylphosphine dichloride and the efficient one-pot reductive conversion of phosphine oxide to triphenylphosphine

Electroreduction of triphenylphosphine dichloride in acetonitrile was performed successfully in an undivided cell fitted with an aluminium sacrificial anode and a platinum cathode. Further, the one-pot transformation of triphenylphosphine oxide to triphenylphosphine was achieved successfully by the treatment of triphenylphosphine oxide in acetonitrile with oxalyl chloride and subsequent electrochemical reduction.     

Molecular diversity of triphenylphosphine promoted reaction of electron-deficient alkynes and arylidene Meldrum acid (N,N'-dimethylbarbituric acid)

The three-component reaction of triphenylphosphine, dimethyl hex-2-en-4-ynedioate and arylidene N,N'-dimethylbarbituric acids in dry methylene dichloride at room temperature afforded trans-1,3-disubstituted 7,9-diazaspiro[4.5]dec-1-enes in good yields and with high diastereoselectivity. However, the similar three-component reaction with arylidene Meldrum acids resulted in a mixtures of cis/trans-1,2-disubstituted 7,9-dioxaspiro[4.5]dec-1-enes. Additionally, the three-component reaction of triphenylphosphine, dimethyl but-2-ynedioate and arylidene Meldrum acids gave polysubstituted 5-(triphenyl-λ⁵-phosphanylidene)cyclopenta-1,3-dienes. A plausible reaction mechanism was proposed for the formation of various products with different regioselectivity and diastereoselectivity.     

Neues Verfahren zur Darstellung von Phosphorsäureesteramiden,Phosphinsäureamiden,Phosphinsäureestern und gemischt substituierten Phosphorsäuretriestern

A New Synthesis of Phosphoric Acid Ester Amides, Phosphinic Acid Amides, Phosphinic Acid Esters and Mixed Substituted Phosphoric Acid Triesters The system triphenylphosphine/carbon tetrachloride may be used as a dehydrating agent for the intermolecular amide and ester condensation of phosphoric acid mono- or diesters and phosphinic acids. Conveniently the process is carried out as a simultaneous reaction at room temperature with the four components phosphoric acid/phosphine/carbon tetrachloride/amine (alcohol).     

Synthesis of phosphorus‐containing vinyl ether monomers and oligomers and their photoinitiated polymerization

Divinyl ether monomers containing phosphorous residues were synthesized by the addition reaction of glycidyl vinyl ether (GVE) with various phosphonic dichlorides or dichlorophosphates with quaternary onium salts as catalysts. The reaction of GVE with phenylphosphonic dichloride gave bis[1‐(chloromethyl)‐2‐(vinyloxy)ethyl]phenylphosphonate ( 1a ) in a 77% yield. The polycondensation of 1a with terephthalic acid was also carried out with 1,8‐diazabicyclo[5.4.0]undecene‐7 (DBU) as a condensing agent to afford the corresponding phosphorus‐containing polyester. A multifunctional monomer containing both vinyl ether groups and methacrylate groups was prepared by the reaction of 1a with methacrylic acid with DBU. The photoinitiated cationic polymerization of these vinyl ether compounds proceeded rapidly with bis[4‐(diphenylsulfonio)phenyl]sulfide‐bishexafluorophosphate as the cationic photoinitiator without a solvent upon ultraviolet irradiation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2031–2042, 2004     

Synthesis of 2-(N-Benzylpyrrolyl)-benzimidazoles Using Polyphosphoric Acid Prompted Cyclocondensation

Synthesis of a series of 2-substituted benzimidazoles was carried out for screening anti-inflammatory activities. 2-(N-benzylpyrrolyl)-benzimidazoles 9a-k were synthesized from N-benzyl-2-pyrrole carboxylic acids 8a-d and 4-substituted-1,2-phenylenediamines by cyclocondensation utilizing polyphosphoric acid (PPA) as condensing agent. The N-benzyl-2-pyrrole carboxylic acids were prepared by standard method of N-benzylation of 2-pyrrole carboxylate using NaH/DMF and appropriately substituted benzyl halides followed by alkaline hydrolysis.     

Synthesis of poly(benzoxazinone)s by direct polycondensation of dicarboxylic acids with bis(anthranilic acid)s

A convenient method for the synthesis of poly(benzoxazinone)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl ether structures with bis(anthranilic acid)s using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensations proceeded smoothly and were completed within several hours at 140°C to produce poly(benzoxazinone)s with inherent viscosities up to 2.6 dL/g. The synthesis of 2-substituted benzoxazinones by the reaction of aromatic carboxylic acids or dicarboxylic acid with anthranilic acid in PPMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(benzoxazinone)s showed 10% weight loss in air and nitrogen around at 440 and 460°C, respectively.     

Evaluation of functionalized silica's for the adsorptive recovery of homogenous catalysts through interaction with the metal centre

The goal of this paper is the evaluation of functionalized silica's for the recovery of homogeneous catalysts by adsorption via its metal centre. As model catalysts, we selected bis(triphenylphosphine)cobalt(II)dichloride (CoCl(2)(PPh(3))(2)), bis(triphenylphosphine)palladium(II)dichloride (PdCl(2)(PPh(3))(2)) and tris(triphenylphosphine)rhodium(I)dichloride (RhCl(PPh(3))(3)). Twelve functionalized groups selected from four classes containing one or more N-, O-, P- or S-atoms were evaluated. A preliminary selection of the adsorbents was done by investigating the adsorption of the metal salts for the cobalt and the palladium complex. The results could be explained by the Hard and Soft Acid Base (HSAB) theory. For the most suitable functionalized adsorbents, these experiments were extended by introducing the ligand in the system which promoted the competition of the functionalized groups on adsorbent and the ligands present in solution. These experiments demonstrated that different complex species are adsorbed. 2-(2pyridyl)ethyl-functionalized silica is selected as a promising adsorbent for adsorption of the CoCl(2)(PPh(3))(2) from acetonitrile, while 3-(mercapto)propyl-functionalized silica is selected as a promising adsorbent for adsorption of the PdCl(2)(PPh(3))(2) and RhCl(PPh(3))(3) from DMF. The presence of a ligand, an increase of the temperature and the presence of a solvent with the donor properties can decrease the adsorption equilibrium and need to be taken into account.     

Reaction of 2,3-Dihalopropionic Acids and Their Derivatives with P- and N-Nucleophiles

3-(Triphenylphosphoniochlorido)acrylic and 2,3-dichloropropionic acids react with triphenylphosphine to form 1,2-bis(triphenylphosphoniochlorido)ethane. Under analogous conditions, 2,3-dibromopropionic acid undergoes debromination followed by triphenylphosphine addition to give, after water treatment, 3-(triphenylphosphoniobromido)propionic acid. 2,3-Dihalopropionitriles react similarly, providing 3-(triphenylphosphoniohalido) propionitriles. The reaction of 2,3-dibromopropionamide with triphenylphosphine was performed to show that E-(triphenylphosphoniobromido)acrylic acid is capable, by contrast to what was reported previously, of reacting with triphenylphosphine. Pyridine forms with 2,3-dihalopropionic acids vinylpyridinium halides, while the reactions with aliphatic amines gives rise to dehydrohalogenation products.     

Adduct of Triphenylphosphine Oxide and Sulfuric Acid: Synthesis and Structure

Adduct of triphenylphosphine oxide and sulfuric acid was synthesized by reacting arenesulfonic acids with triphenylphosphine oxide (1 : 2) in the presence of the moisture of air. According to the X-ray diffraction data, the phosphorous atom has a distorted tetrahedral coordination. The sulfuric acid molecule is disordered over two sites and is linked with two triphenylphosphine oxide molecules through hydrogen bonds.     

Aromatic polyesters obtained directly from hydroxybenzoic acids by hexachlorocyclotriphosphatriazene (PNC) in pyridine

Polyaryl esters of moderate molecular weights were prepared by the direct polycondensation reaction of hydroxybenzoic acids and its derivatives with hexachlorocyclotriphosphatriazene (also known as phosphonitrilic chloride trimer, PNC) as a condensing agent in pyridine. Copolymerization of p-hydroxybenzoic acid with several hydroxybenzic acid derivatives was carried out to improve the processability of the polymer of p-hydroxybenzoic acid, which yields fusible and soluble copolymers of high inherent viscosities. Polymer solubility and thermal behavior were examined.     

One-pot two-step synthesis of 4-vinylphenols from 4-hydroxy substituted benzaldehydes under microwave irradiation: a new perspective on the classical Knoevenagel-Doebner reaction

The classical Knoevenagel-Doebner reaction is reinvestigated wherein the direct synthesis of substituted 4-vinylphenols instead of the expected 4-hydroxycinnamic acids is described. The condensation reaction is performed on 4-hydroxy substituted benzaldehydes and malonic acid with a mixture of acetic acid-piperidine as condensing agent under focused microwave irradiation. The occurrence of simultaneous condensation-double decarboxylation without the use of any decarboxylating agent is a new finding, the reaction being facilitated solely by the hydroxy substituent and microwave irradiation effect.     

Synthesis of aromatic poly(thioether ketone)

Aromatic poly(thioether ketone)s were prepared by the direct polycondensation of aromatic dicarboxylic acids with aryl compounds containing ether or sulfide structures using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensation proceeded smoothly and produced aromatic poly(thioether ketone)s with inherent viscosities up to 0.73 dL/g. The synthesis of substituted aryl ketones by the reaction of substituted benzoic acids with aryl compounds in PMMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(thioether ketone)s showed a 10% weight loss in air and nitrogen at around 450 and 460°C, respectively. © 1992 John Wiley & Sons, Inc.     

Specificity of the reaction of β-carboxyvinyl(triphenyl)phosphonium chloride with azoles

Reactions of pyrazole, 3,5-dimethylpyrazole, 1,2,4-triazole, 5-aminotetrazole, and imidazole with β-carboxyvinyl(triphenyl)phosphonium chloride in boiling acetonitrile are accompanied by elimination of azole with formation of the initial salt and elimination of triphenylphosphine to give the corresponding azole hydrochloride and α-azolyacrylic acid. In all cases, ethylenebis(triphenylphosphonium) dichloride was formed, and the reactions with the most nucleophilic 3,5-dimethylpyrazole and imidazole also led to their adducts with α-azolylacrylic acid. In the reactions of pyrazole and 3,5-dimethylpyrazole with β-carboxyvinyl-(triphenyl)phosphonium chloride at room temperature, the conesponding addition products were isolated in almost quantitative yield.     

Synthese von Hydroxybenzylbenzimidazolen

Zusammenfassung Eine Reihe von Hydroxybenzylbenzimidazolen wurde durch Kondensation verschiedener aromatischer o-Diamine mit Brommandelsäuren unter Verwendung von 6n-HCl als Kondensationsmittel hergestellt. Für die Substituenten in der Benzolhälfte wurden die Stellungen 4(7)-, 5(6)-, 5,6- oder 4,6(5,7)- ge-wählt; der Phenylrest der Hydroxybenzylhälfte trägt ein Bromatom in der o- oder p-Stellung. Die Darstellung der o-Brom-mandelsäure wird beschrieben.

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A series of hydroxybenzylbenzimidazoles has been synthesized by condensing various aromatic o-diamines with bromomandelic acids using 6 N hydrochloric acid as condensing agent. o-Phenylene diamines to yield benzimidazoles substituted at positions 4(7)-, 5(6)- or 4,6(5,7)- were selected; the phenyl group of the hydroxybenzyl moiety carries a bromo substituent in the o- or p-position. The preparation of o-bromomandelic acid is described in some detail.

     

Synthesis of ordered polymer by direct polycondensation. VIII. Ordered polymer from two nonsymmetric monomers

The ordered (-aacdbbdc-) polymer was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 4,4′-(oxydi-p-phenylene)dibutanoic acid (XaaX) and 2-methoxyisophthalic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate ( 1 ). The polymerization was carried out by a one-pot procedure, that is, mixing the dicarboxylic acids, condensing agent 1 and triethylamine in NMP for 2 h at room temperature, followed by the addition of 4-aminobenzhydrazide. This polymerization proceeded smoothly, yielding the ordered polymer with an inherent viscosity of 0.34 dL g⁻¹. The microstructure of the ordered polymer was confirmed by comparing the authentic ordered polymer in their ¹³C-NMR spectrum. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2309–2314, 1998     

Direct polyesterification promoted by a complex of phosphorus oxychloride with LiCl monohydrate

The reaction of benzoic acid and p-chlorophenol with phosphorus oxychloride (POC) was significantly affected by the presence of metal salt hydrates or a mixture of metal salts and water sufficiently aged. Among metal salts examined, LiCl was most effective for the reaction to give quantitative yield of the benzoate. The reaction was assumed to proceed via a complexation of POC with LiCl monohydrate followed by selective hydrolysis of POC by water bound to LiCl. The reaction promoted by a complex derived from POC and LiCl monohydrate in pyridine was successfully used as a new condensing agent for the synthesis of aromatic polyesters by the direct polycondensation or aromatic dicarboxylic acids and bisphenols. Under favorable conditions for aging of POC with LiCl monohydrate and for addition of bisphenols, polymers of moderate to high molecular weights were obtained in quantitative yield. The reaction was applied with limited success to the preparation of a copolymer of high molecular weight from hydroxybenzoic acids.