Polyphosphoric Ester Research Articles

A NOVEL ONE-POT SYNTHESIS METHOD OF 3,4,5-TRIARYL-SUBSTITUTED 1,2,4-TRIAZOLES

A novel method for the preparation of 3,4,5-triaryl-substituted 1,2,4-triazoles by the reaction of hydrazides with secondary amides in polyphosphoric ester has been developed. The new method is characterized by mild conditions and ease of synthesis, including the stages of isolation and purification of the product. Additionally, product structures were confirmed by counter synthesis. It was shown that the proposed method is suitable for producing 1,2,4-triazoles with phenolic substituents without the stages of the protection and deprotection of the hydroxyl group. Using the new method, five 3,4,5-substituted 1,2,4-triazoles were obtained for the first time.

A novel one-pot synthesis method of 3,4,5-triaryl-substituted 1,2,4-triazoles

A novel method for the preparation of 3,4,5-triaryl-substituted 1,2,4-triazoles by the reaction of hydrazides with secondary amides in polyphosphoric ester has been developed. The new method is characterized by mild conditions and ease of synthesis, including the stages of isolation and purification of the product. Additionally, product structures were confirmed by counter synthesis. It was shown that the proposed method is suitable for producing 1,2,4-triazoles with phenolic substituents without the stages of the protection and deprotection of the hydroxyl group. Using the new method, five 3,4,5-substituted 1,2,4-triazoles were obtained for the first time.

Fluorometric Recognition of Nucleotides within a Water-Soluble Tetrahedral Capsule.

The design of aqueous probes and binders for complex, biologically relevant anions presents a key challenge in supramolecular chemistry. Herein, a tetrahedral assembly with cationic faces and corners is reported that is capable of discriminating between anionic and neutral guests in water. Electrostatic repulsion between subcomponents can be overcome by the addition of an anionic template, or generating a robust covalent framework by incorporating tris(2-aminoethyl)amine (TREN). The resultant TREN-capped, water-soluble, fluorescent cage binds mono- and poly-phosphoric esters, including nucleotides. Its covalent skeleton renders it stable at micromolar concentrations in water, enabling the fluorometric detection of biologically relevant guests in an aqueous environment. Selective supramolecular encapsulants, such as 1, could enable new sensing applications, such as recognition of toxins and drugs, under biological conditions.

Preparation of 1-methyl-3-phenylisoquinoline derivatives from oximes using polyphosphoric esters

1-Methyl-3-phenylisoquinoline derivatives were synthesized with high efficiency from oximesviaBeckmann rearrangement, isomerization and condensation, all promoted by polyphosphate ester.

ChemInform Abstract: Stereoselective Syntheses of Substituted 5,6-Dihydro-2(1H)-pyridinones in Polyphosphate Media.

delta-Lactams have been synthesized with excellent stereocontrol of substituents by condensing 3-alkenamides with aryl aldehydes in polyphosphoric ester. The scope of the condensation of 3-alkenamides with aryl aldehydes in several phosphate media is examined, and a rationale is proposed regarding gamma-lactam versus delta-lactam formation.

Photoelectrochemical Study of Pitting on Iron in Borate Buffer Solution Containing Inhibitor

Abstract The photoelectrochemical behavior and the susceptibility of iron to pitting in borate buffer containing chloride ions (Cl−) were investigated in the presence and absence of inhibitor PC-604, which is a mixture of polyhydric alcohol phosphoric ester and polyphosphoric ester of various molecular weights. Measurements of the band gap (Eg) of the passive film on iron showed inhibitor concentration and passivation time did not interfere with Eg. Photocurrent and photocurrent transients increased with increasing inhibitor quantities and passivation times at constant potential. The decay time-constant of the photocurrent transient was investigated as a specific parameter of the film. Data showed this parameter was related to pitting susceptibility of the passive film on iron.

A Cyclodehydration Route to 2-Aminochromones

Abstract Cyclodehydration of a series of salicylacetamides with triflic anhydride efficiently provided the corresponding 2-aminochromone. The use of polyphosphoric ester for this process was somewhat less effective.

Stereoselective syntheses of substituted 5,6-dihydro-2(1H)-pyridinones in polyphosphate media

delta-Lactams have been synthesized with excellent stereocontrol of substituents by condensing 3-alkenamides with aryl aldehydes in polyphosphoric ester. The scope of the condensation of 3-alkenamides with aryl aldehydes in several phosphate media is examined, and a rationale is proposed regarding gamma-lactam versus delta-lactam formation.

Stereocontrolled syntheses of substituted unsaturated .delta.-lactams from 3-alkenamides

δ-Lactams have been synthesized with excellent stereocontrol of substituents by condensing 3-alkenamides with aryl aldehydes in polyphosphoric ester

Synthesis of the alkaloid dioxyline and other 6,7-dimethoxyisoquinolines in a modified ritter reaction

It has been found that aceto- and benzonitriles and 3,4-dimethoxyphenylacetone in the presence of acetylperchlorate or upon heating in polyphosphoric acid or polyphosphoric ester form the corresponding isoquinoline. The data indicate that the reaction proceeds like a typical Ritter reaction and is defined by electrophilic activation of the carbonyl group of the ketone and the nucleophilicity of the nitrile. This methodology gave the alkaloid dioxyline (dimoxyline), obtained in high yield by the use of benzoylhexachloroantimonate.

Fire retardance of polyethylene: Study of a formulation involving phosphorus and polyol systems

The fire retardance of low-density polyethylene has been achieved using a formulation based on the use of phosphoric esters of various polyols in association with a formo- p-cresolic resin (PCR). Two methods of implementation have been studied. The first consists in synthesizing the fire retardant before its incorporation into the polymer, while the second consists in making P 2O 5 react directly with the polyol while processing the polymer. This second route results in better efficiency. The formulation has been optimized by systematic study of the influence of various parameters such as additive load, nature of the alcohol, P 2O 5/alcohol ratio, etc. The best formulation is based on pentaerythritol (PER) and shows an oxygen index of 29·5 with the composition: PE + 25%[(P 2O 5/PER, 1 : 1)/PCR, 2 3 : 1 3 Extensive spectroscopic study of the material results in the proposal that the fire retardant has the structure of a polyphosphoric ester of pentaerythritol which keeps free alcoholic functions. Analysis of chars obtained in air at 400°C from the flame-proofed polymer confirms that phosphorus acts mainly in the condensed phase, eventually accumulating at the surface, most likely in the form of polyphosphoric acid.

Bisindoles. 28. Synthesis of 7,7?-dimethyl-5,5?-bis-1H-indole

Cyclization of the 3,3′-dimethyl-4,4′-diphenylendihydrazone of ethyl pyruvate in polyphosphoric ester gave 7,7′-dimethyl-2,2′-dicarbethoxy-5,5′-bis-1H-indole which was hydrolyzed and decarboxylated to give 7,7′-dimethyl-5,5′-bis-1H-indole.

β‐Carbolines as agonistic or antagonistic benzodiazepine receptor ligands. 1. Synthesis of some 5‐, 6‐ and 7‐amino derivatives of 3‐methoxycarbonyl‐β‐carboline (β‐CCM) and of 3‐ethoxycarbonyl‐β‐carboline (β‐CCE)

AbstractCondensation of diethyl formylamino‐ or diethyl acetylaminomalonate with 4‐, 5‐ or 6‐nitrogramine 1 afforded the diethyl formylamino‐ or the diethyl acetylamino[(nitroindol)‐3‐ylmethyl]malonates 2; reduction of the nitro group followed by N‐formylation or acetylation of the resulting amino compounds 3, led to the 4‐, 5‐and 6‐acylamino derivatives 4.Cyclization of 4 in the presence of polyphosphoric esters gave the 3,3‐bis(ethoxycarbonyl)‐3,4‐dihydro‐β‐carbolines 5, which underwent lithium chloride/water catalyzed monodeethoxycarbonylation to the corresponding 5‐, 6‐ and 7‐acylamino‐3‐ethoxycarbonyl‐β‐carbolines 6, whose acidic hydrolysis led finally to the 5‐, 6‐ and 7‐amino‐3‐ethoxycarbonyl‐β‐carbolines 9. The 6‐amino compounds 9b‐e were obtained also by direct nitration of 3‐methoxycarbonyl‐β‐carboline 7a and of 3‐ethoxycarbonyl‐β‐carboline 7c, followed by the nitro group reduction of the resulting nitro carbolines 8.Preliminary studies of the binding to rabbit brain benzodiazepine receptor sites indicate compounds 9b and 9c to inhibit the 3H‐diazepam binding at 10−8 M concentrations.

Reactions of some N-acyl-1-alkylamines with poly phosphoric ester PPE: nuclear magnetic resonance and stereochemistry of reaction products

Phenylindanes were obtained from the reaction of N-acyl-1-arylalkylamines with polyphosphoric ester (PPE). cis-1-Methyl-3-(3,4-dimethoxyphenyl)-5,6-dimethoxyindane was synthesized to determine which stereoisomer was produced by N-formyl and N-acetyl-1-(3,4-dimethoxyphenyl)ethylamine with PPE. Nuclear magnetic resonance specra (1H and 13C) of several mono-, 1,3-di-, and 1,2,3-tri-substituted indanes were fully analyzed to provide information on steric interactions and conformation of the cyclopentene ring. Possible cyclodimerization pathways are proposed.

NMR study of the lability of the thiazolium proton in thiamin and its polyphosphoric esters

The purpose of the present paper is to study the exchange rate of the hydrogen at the C-2 position of the thiazolium ring in thiamin and its polyphosphoric esters, by NMR spectroscopy. This rate is determined by following the corresponding signal intensity of the NMR spectrum in 2H 2O. It has been found that the rate of exchange increases with pH, and that this increase is greater as the polyphosphoric chain becomes longer. Data show us that the half-life time of this exchange for thiamin at a pH value of about 9 is the same as that for diphosphothiamin at a lower pH range.

The use of polyphosphoric ester and polyphosphoric acid in the synthesis of 1,4-dihydro-4-oxoquinolines

The synthesis of 1-alkyl-1,4-dihydro-4-oxoquinolines by the cyclization of derivatives of 2-(N-alkylanilino)acrylic acid in the presence of polyphosphoric acid or ester has been investigated. The results indicate that polyphosphoric ester is a more efficient reagent for the cyclization of 2-(N-alkylanilino)acrylic acid derivatives than polyphosphoric acid and also has advantages over the thermal cyclization.

On polycondensation of ribonucleotides under the action of polyphosphoric ester

On polycondensation of ribonucleotides under the action of polyphosphoric ester

On the structure of polynucleotides obtained by condensation of nucleoside 2′(3′)-phosphates with polyphosphoric ester

On the structure of polynucleotides obtained by condensation of nucleoside 2′(3′)-phosphates with polyphosphoric ester