HCl Acceptor Research Articles

Synthesis of Amidophosphates Based on 1-Ethynyl-1-Aminocyclohexane Upon Microwave Activation and their Biological Activity

The researches for developing the methods for synthesizing new functionally substituted derivatives of alicyclic dialkylamidophosphates, establishing their structure, and searching for promising biologically active compounds in their series, are modern and relevant. The given study aimed to develop the synthesis of amidophosphates based on the example of phosphorylation of 1-ethynyl-1- aminocyclohexane with dialkyl phosphites in the presence of triethylamine in carbon tetrachloride in the Atherton-Todd reaction conditions using microwave irradiation of the reaction mixture. The reaction of 1-ethynyl-1-aminocyclohexane with dialkyl phosphites was carried out in a CCl4 excess at an equimolar ratio of reagents, triethylamine was used as an HCl acceptor. The highest yields of dialkyl- N-(1-ethynylcyclohexan-1-yl)amidophosphates were achieved by adding equimolar amounts of dialkyl phosphites to the mixture of 1-ethynyl-1-aminocyclohexane, triethylamine, and CCl4 followed by the subsequent activation of the mixture in a microwave reactor (MAS-II Plus MW) (MW 102 W, 115 °C, microwave irradiation time was 3‒5 min). The composition and structure of the obtained compounds were proved by elemental analysis, IR, 1H, 13C, 31P NMR spectroscopy, and X-ray diffraction analysis (XRD). The biological tests carried out in laboratory and field conditions allowed identifying diethyl-N-(1-ethynylcyclohexan-1-yl) amidophosphate among the synthesized compounds, which produces a high growth-regulating effect on the growth, development, and yield of agricultural crops.

Membrane-based liquid-phase microextraction of basic pharmaceuticals – A study on the optimal extraction window

The present paper defines the optimal extraction window (OEW) for three-phase membrane-based liquid-phase microextraction (MP-LPME) in terms of analyte polarity (log P), and anchors this to existing theories for equilibrium partitioning and kinetics. Using deep eutectic solvents (DES) as supported liquid membranes (SLM), we investigated how the OEW was affected by ionic-, hydrogen bond and π-π interactions between the SLM and analyte. Eleven basic model analytes in the range -0.4 < log P < 5.0 were extracted by MB-LPME in a 96-well format. Extraction was performed from 250 µL standard solution in 25 mM phosphate buffer (pH 7.0) into 50 µL of 10 mM HCl acceptor solution (pH 2.0) with mixtures of coumarin, camphor, DL-menthol, and thymol, with and without the ionic carrier di(2-ethylhexyl) phosphate (DEHP), as the SLM. The OEW with pure DES was in the range 2 < log P < 5, and low SLM aromaticity was favorable for the extraction of non-polar analytes. Here, extraction recoveries up to 98% were obtained. Upon addition of DEHP to the SLMs, the OEW shifted to the range -0.5 < log P < 2, and a combination of 5% DEHP and moderate aromaticity resulted in extraction recoveries up to 80% for the polar analytes. Extraction with ionic carrier was inefficient for the non-polar analytes, due to excessive trapping in the SLM. The results from our study show that LPME performs optimally in a relatively narrow log P-window of ≈ 2–3 units and that the OEW is primarily affected by ionic carrier and aromaticity.

Selective electromembrane extraction and sensitive colorimetric detection of copper(II)

Abstract In this study, an extremely effective electromembrane extraction (EME) method was developed for the selective extraction of Cu(II) followed by Red-Green-Blue (RGB) detection. The effective parameters optimized for the extraction efficiency of EME include applied voltage, extraction time, supported liquid membrane (SLM) composition, pH of acceptor/donor phases, and stirring rate. Under optimized conditions, Cu(II) was extracted from a 3 mL aqueous donor phase to 8 µL of 100 mM HCl acceptor solution through 1-octanol SLM using an applied voltage of 50 V for 15 min. The proposed method provides a working range of 0.1–0.75 µg·mL−1 with 0.03 µg·mL−1 limit for detection. Finally, the developed technique was applied to different environmental water samples for monitoring environmental pollution. Obtained relative recoveries were within the range of 93–106%. The relative standard deviation (RSD) and enhancement factor (EF) were found to be ≤4.8% and 100 respectively. We hope that this method can be introduced for quantitative determination of Cu(II) as a fast, simple, portable, inexpensive, effective, and precise procedure.

Synthesis of Bisphenol A Based Phosphazene-Containing Epoxy Resin with Reduced Viscosity.

Phosphazene-containing epoxy oligomers (PEO) were synthesized by the interaction of hexachlorocyclotriphosphazene (HCP), phenol, and bisphenol A in a medium of excess of epichlorohydrin using potassium carbonate and hydroxide as HCl acceptors with the aim of obtaining a product with lower viscosity and higher phosphazene content. PEOs are mixtures of epoxycyclophosphazene (ECP) and a conventional organic epoxy resin based on bisphenol A in an amount controlled by the ratio of the initial mono- and diphenol. According to 31P NMR spectroscopy, pentasubstituted aryloxycyclotrophosphazene compounds predominate in the ECP composition. The relative content in the ECP radicals of mono- and diphenol was determined by the MALDI-TOF mass spectrometry method. The organic epoxy fraction, according to gas chromatograpy-mass spectrometry (GC-MS), contains 50–70 wt % diglycidyl ether of bisphenol A. PEO resins obtained in the present work have reduced viscosity when compared to other known phosphazene-containging epoxy resins while phosphazene content is still about 50 wt %. Resins with an epoxy number within 12–17 wt %, are cured by conventional curing agents to form compositions with flame-retardant properties, while other characteristics of these compositions are at the level of conventional epoxy materials.

СИНТЕЗ ТА ДОСЛІДЖЕННЯ ТЕРМОСТАБІЛІЗУЮЧОЇ ДІЇ НА ПОЛІСТИРОЛ МЕТАКРИЛОВИХ МОНОМЕРІВ НА ОСНОВІ АУРОНУ

In this work, 6-hydroxy- and 4'-hydroxyaurones were synthesized by condensation reaction of 6-hydroxybenzofuran-3-one with benzaldehyde and benzofuran-3-one with 4-hydroxybenzaldehyde. Methacrylic monomers – (2Z)-6-methacryloxy-2-(4-R-benzylidene)-1-benzofuran-3-(2H)-one and a new 4-[(Z)-(3-oxo-1-benzofuran-2-(3H)ilidene)methyl]phenyl-2-methyl acrylate were obtained by acylation with the methacryloyl chloride in the presence of triethylamine as HCl acceptor at the temperature 0–5°C. These monomers were synthesized to create special purpose polymers. New methacrylic derivatives are not deeply painted and stable in air crystalline monomers. The structure of the synthesized compounds was confirmed by spectral methods. 1H NMR (400 MHz) spectra were recorded on a Mercury (Varian) 400 spectrometer with tetramethylsilane as internal standard in DMSO-d6. The intrachain thermostabilizing effect of these monomers on the polystyrene destruction processes was studied. Polystyrene and its modified samples were obtained by radical thermoinitiated polymerization (initiator – azo-bis-isobutyronitrile – 1 mass percent) in ethyl acetate at the temperature 78°C during 16 hours. In a case modified samples, 3 mol percent of aurone containing monomers were added. Destruction of modified polystyrene was studied by using dynamic thermogravimetric analysis. Destruction of modified polystyrene was carried out in a Simultaneous Differential Thermogravimetric Analyzer which combines a heat-flux type DTA with a TGA (Shimadzu, DTG-60, Japan). Simultaneous TG, DTG and DTA curves were obtained and sample weight loss as functions of time and temperature were recorded continuously under dynamic conditions. Sintered a-alumina was used as the reference material. Sample with mass of 4 mg was inserted directly into platin crucible and temperature was ramped from 20 to 600°C. The heating rates were controlled at 10°C/min. Experiments were performed under an air atmosphere. It was established, that the investigated additives covalently attached to the polystyrene are inhibited the polystyrene destruction processes. Moreover, the additive with the methacrylic group in 6-position of the aurone is significantly more efficient than with the methacrylic group in 4’- position. It has been shown that samples of modified polystyrene by the applications of 4'-methacryloxy aurone and 6-methacryloxy aurone are more thermostable than the industrial sample of polystyrene of brand STYRON (Switzerland). It was shown that the temperature of 10% of the mass loss of modified samples is higher on 14–34 degrees than for the sample of polystyrene of brand STYRON. Thus, the new additives could be proposed for thermostabilizing of polystyrene production.

Low-voltage electrochemically stimulated stir membrane liquid-liquid microextraction as a novel technique for the determination of methadone

In the present work, for the first time, a new portable setup was designed, developed and presented for the extraction of methadone, as a basic drug model from biological fluid samples using a low-voltage electrically stimulated stir membrane liquid–liquid microextraction technique (LV-ESSM-LLME), followed by high-performance liquid chromatography with ultraviolet detection. This new approach combines the advantages of stir membrane liquid–liquid microextraction and electrokinetic migration in the same unit under soft electrochemical conditions in a portable device, allowing for the isolation and preconcentration of the target analyte in a simple and efficient manner under three-phase mode. To investigate the influence of external stirring and the application of electrical potential as the driving force, a comparative study of all variables involved in the extraction process was carried out using the low-voltage electromembrane extraction (LV-EME) and LV-ESSM-LLME methods. Under soft electrokinetic migration conditions, methadone was transported from an acidic sample solution (pH 4.0), through the NPOE immobilized in the pores of the porous polypropylene sheet membrane, and into 25µL of 10mmolL−1 HCl acceptor solution with a stirring rate of 1000rpm and 700rpm after 15min and 20min for LV-ESSM-LLME and LV-EME, respectively. Under the optimized conditions, preconcentration factors in the range of 17–24 and 21.5–29 for LV-EME and LV-ESSM-LLME, respectively, were considered, and satisfactory repeatability (4.5<[RSD]<7.5) was obtained in different matrices. The obtained relative recoveries of the target analyte were in the range of 87–94% and 93–101% for LV-EME and LV-ESSM-LLME, respectively, which indicated the excellent capability of the developed methods to extract methadone from complex matrices.

On the reactions of chlorodithiophosphoric acid pyridiniumbetaine with polyfunctional nucleophiles. Part IV: Reactions with thiosemicarbazide monoaryl derivatives

In connection with our previous research, reactions of chlorodithiophosphoric acid pyridiniumbetaine, py.PS2Cl (I), with monoaryl thiosemicarbazide derivatives RN(H)C(S)N(H)NH2, (R=phenyl, 4-nitrophenyl) were studied with the aim to prepare new heterocyclic compounds. All reactions were carried out in acetonitrile in the presence of pyridine as an HCl acceptor. New compounds, pyridinium salts of 4-phenyl-3-sulfido-3,5-dithioxo-1,2,4,3λ5-triazaphospholidine (II) and 4-(4-nitrophenyl)-3-sulfido-3,5-dithioxo-1,2,4,3λ5-triazaphospholidine (III) were prepared. 31P NMR, FT-IR, Raman spectroscopy, and X-ray diffraction analysis revealed their molecular structures consisting of pyridinium cation and five-membered P–N–N–C–N heterocyclic anion bearing relevant aryl group.

A Synthetic Route to a Molecular Galloxane Dihydroxide and Its Group 4 Heterobimetallic Compounds

Controlled hydrolysis of (Me)LGaCl2 ((Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) (1) in the presence of a N-heterocyclic carbene, as a HCl acceptor, led to the unprecedented molecular galloxane dihydroxide [{(Me)LGa(OH)}2(μ-O)] (2) in high yield. Compound 2 was used in the assembly of the heterobimetallic galloxanes with group 4 metals [{((Me)LGa)2(μ-O)}(μ-O)2{M(NR2)2}] (M = Ti, R = Me (6); M = Zr (7), Hf (8), R = Et).

Use of pyrazolyl ligands for the formation of a bimetallic cobalt–ruthenium complex

A straightforward route to Ru(pyz) 2(Hpyz) 4 (Hpyz = pyrazole) has been developed. This has been found to react readily with a modified Co(pyrazolylborate)Cl complex in the presence of triethylamine as an HCl acceptor to yield a bimetallic cobalt–ruthenium complex, in which the two metals are each six-coordinate, and bridged by three pyrazolyl anions. Both species have been characterized structurally, as has a modified Co(pyrazolylborate) 2 complex.

Organic-metalloblock copolymers via photocontrolled living anionic ring-opening polymerization

A new method for the preparation of organic-organometallic diblock copolymers including a polyferrocenylsilane (PFS) metalloblock through photocontrolled ring-opening polymerization (ROP) is reported. Polystyrene (PS) homopolymers end-capped with a cyclopentadienyl group (1) were used as macroinitiators for the photocontrolled ROP of sila[1]ferrocenophanes [Fe(η-C5H4)2Si{C≡CtBu}2] 3a and [Fe(η-C5H4)2Si(Me)(C≡CSiMe3)] 3b to afford diblock copolymers with controlled molecular weights and block ratios, as well as low polydispersities (PDI < 1.2). Block copolymer PSm-b-[Fe(η-C5H4)2Si{C≡C(t-Bu)}2]n4 was clusterized with [Co2(CO)8], forming the highly metallized PSm-b-[Fe(η-C5H4)2Si{Co2(CO)6C2(t-Bu)}2]n (PS-bb-(Co-PFS), 7). The diblock PSm-b-[Fe(η-C5H4)2Si(Me)(C≡CH)]n6 was prepared by selective desilylation of PSm-b-[Fe(η-C5H4)2Si(Me)(C≡CSiMe3)]n5 was then reacted with ClAuP(n-Bu)3 in the presence of an amine as HCl acceptor to afford PSm-b-[Fe(η-C5H4)2Si(Me){C≡CAuP(n-Bu)3}]n (PS-bbb-(Au-PFS), 8). Preliminary studies on the self-assembly of these materials in thin films showed phase separation with metal-rich nanodomains within an organic matrix.

ChemInform Abstract: The First Synthesis of Fluorine-Containing Indeno[2,1c][1,2,6]-selenadiazines.

Abstract 4-Trifluoromethyl-4a-chloro-5,6,7,8,9,9-hexafluoro(4aH,9H)indeno[2,1c][1,2,6]-selenadiazine (1) has been synthesised by the interaction of 2-amino-3-(1-imino-2,2,2-trifluoroethyl)hexafluoroindene (2) with SeCl4 in the presence of HCl acceptors. Hydrolysis and reaction with CF3SO3H are also described. Arrangement of atoms for 1 are provided.

Bioactive Heterocyclic Trithiophosphoric Esters: Synthesis and Bioactivity

Novel, heterocyclic derivatives of trithiophosphoric acid have been achieved through phosphorylation of quaternary salts of N-heterocycles with phosphorus trichloride, the iminohalophosphines, thus obtained in situ were subjected to nucleophilic substitution with mercaptans in organic solvents in the presence of HCl acceptors, preferably triethylamine. Synthesized derivatives exhibited potential insecticidal behavior against a polyphagous insect Plutella xylostella (Diamond Backmoth).

Multicyclic Poly(ether ester)s by Polycondensation of Oligo(ethylene glycol)s and Trimesoyl Chloride

Monodisperse oligo(ethylene glycol)s were polycondensed with trimesoyl chloride using triethylamine as HCl acceptor. Despite nearly quantitative conversions and relatively high concentrations (0.4 mol/L), no gelation occurred with tri- and tetra(ethylene glycol), regardless of the feed ratio. With a feed ratio around 1.5/1.0 multicyclic poly(ether esters)s free of end groups were isolated and characterized by 1H NMR and MALDI-TOF mass spectrometry. At concentrations of 0.2 or 0.4 mol/L di-, penta-, and hexa(ethylene glycol)s yielded gels. At concentrations ≥ 0.2 mol/L exclusively gels were obtained from various α,ω-dihydroxyalkanes. However, soluble multicycles were obtained from 1,8-dihydroxy-3,6-dithiaoctane and from 1,4-bis(2-hydroxyethoxy)-2-butyne. The influence of conformational differences on the cyclization tendency is discussed. The multicycles derived from tri- and tetraethylene glycol showed cryptand properties and dissolved Li-, Na-, K-, and Cs-benzoate in tetrahydrofuran.

On the reactions of chlorodithiophosphoric acid pyridiniumbetaine with polyfunctional nucleophiles. Part III: Reactions with monoalkylderivatives of thiosemicarbazide

Reactions of chlorodithiophosphoric acid pyridiniumbetaine, py · PS 2Cl ( I) with monosubstituted thiosemicarbazide derivatives RN(H)C(S)N(H)NH 2, (R = methyl, ethyl), in acetonitrile media and in the presence of pyridine as an HCl acceptor were studied. New five-membered heterocyclic compounds were prepared, pyridinium salts of 4-methyl-3-sulfido-3,5-dithioxo-1,2,4,3λ 5-triazaphospholidine ( II) and 4-ethyl-3-sulfido-3,5-dithioxo-1,2,4,3λ 5-triazaphospholidine ( III). The substances II and III were completely characterized by 31P NMR, FT-IR, Raman spectroscopies and their molecular structures were determined by the X-ray diffraction analysis.

Liquid-phase microextraction of basic drugs - Selection of extraction mode based on computer calculated solubility data

The extractability of 58 different basic drugs by 3-phase liquid-phase microextraction (LPME) was studied. Extraction recoveries were correlated to solubility data and log D data calculated with a commercial computer program. The basic drugs were extracted from 1.5 mL water samples (pH 13) through approximately 15 microL of dodecyl acetate immobilized within the pores of a porous polypropylene hollow fibre (organic phase), and into 15 microL of 10 mM HCl (acceptor solution) present inside the lumen of the hollow fibre. Compounds with a calculated solubility below 1 mg/mL at pH 2 were poorly recovered and remained principally in the organic phase. For these drugs, 2-phase LPME may be used as an alternative technique, where the aqueous acceptor phase is replaced by an organic solvent. In the solubility range 1-5 mg/mL, most drugs were effectively extracted (recovery >30%), whereas drugs belonging to the solubility range 5-150 mg/mL were all extracted with recoveries above 30% by 3-phase LPME. The hydrophilic nature of most drugs with solubilities above 150 mg/mL prevented them from entering the organic phase, and only those with log D >1.8 were effectively recovered by 3-phase LPME. For drugs with log D < 1.8 (and solubility >150 mg/mL), carrier-mediated LPME was found to be the preferred technique, where an ion-pair reagent (octanoic acid) was added to the sample. In the case of carrier-mediated LPME, the volume of sample was decreased to 100 microL to facilitate rapid extractions. Based on the present work, the extractability of new compounds may easily be predicted to speed up method development. Extractions were also accomplished from plasma samples, where interactions between proteins and the drugs may reduce the extraction recovery. However, dilution of the plasma samples with water and adjustment of pH into the alkaline region effectively suppressed drug-protein interactions for most of the drugs studied.

Preparation of Monomeric LGa(NH2)2 and of LGa(OH)2 in the Presence of a N-Heterocyclic Carbene as HCl Acceptor

The reactions of LGaCl2 (L = HC[C(Me)N(Ar)]2, Ar = 2,6-iPr2C6H3) with NH3 and H2O, respectively, in the presence of a 1,3-bis-tert-butylimidazol-2-ylidene (N-heterocyclic carbene) as acceptor for the HCl lead to unique species of composition LGa(NH2)2 and LGa(OH)2 in high yields under mild conditions. LGa(NH2)2 is the first known monomeric diamide of gallium.

Phosphinite-Phosphine Oxide Isomerization of Diphenylphosphinite Derivatives of 1,4:3,6-Dianhydro-D-mannitol

Phosphorylation of 1,4:3,6-dianhydro-D-mannitol with diphenylphosphinous chloride provided a bisphosphinite derivative that, unlike what is observed in the phosphorylation with phosphorous chlorides and amides, undergoes fast phosphinite-phosphine oxide isomerization. The monophosphinite derivative, in addition, is strongly dephosphorylated. The effect of the solvents and amines (HCl acceptors) on the phosphinite-phosphine oxide isomerization is studied.

A New Neighbouring‐Group Reaction to Form Pyridopyrrolobenzoxazinediones

AbstractThe azaphthalimide 2a is the first phthalimide oxygen found to undergo a neighboring‐group participation reaction with a vicinal N‐phenyl carboxylic acid chloride upon nucleophilic addition with alcohols. Owing to the free rotation of the N‐phenyl moiety, hetero‐anellated benzoxazinedione isomers 3 and 4 are accessible, whereby 3 is preferred to 4 as the pyridine nitrogen in 2a preferentially activates the o‐carbonyl group. Yields of up to 92% were obtained when bases such as HCl acceptors were avoided by heating 2a with alcohols. The reaction is restricted to primary and secondary alcohols, as 2a is nonplanar in respect of the heterocyclic and benzene moiety, which prevents tertiary alcohols attacking the pyrrolidinedione carbonyl group. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2004)

Macrocycles 27: Cyclic aliphatic polyesters of isosorbide

AbstractNumerous polycondensations of isosorbide and suberoyl chloride or other aliphatic dicarboxylic acid dichlorides were performed with pyridine as a catalyst and HCl acceptor. The reaction conditions were varied to optimize both the molecular weight and the fraction of cyclic oligo‐ and polyesters. Furthermore, we attempted to obtain the cyclic monomer by catalyzed back‐biting degradation of the molten cyclic polyesters above 220 °C in vacuo. The polyesters were characterized by viscosity and size exclusion chromatographic measurements as well as matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. In selected cases, mixtures of linear and cyclic polyesters were treated with a hot solution of partially methylated β‐cyclodextrin in methanol. This treatment allowed for a selective extraction of the linear chains up to approximately 5000 Da. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3414–3424, 2003

Polymers of Carbonic Acid, 33

AbstractThe interfacial, hydrolytic polycondensation of bisphenol‐A‐bischloroformate (BABC) was performed at 5 or 35 °C initial temperature with the following amines as catalysts: isoquinoline, pyridine, 4‐methylpyridine, 4‐tert‐butylpyridine, 4‐(dimethylamino)pyridine, 2,4,6‐trimethylpyridine and ethyldiisopropylamine. The reaction products were characterized by viscosity and SEC measurements and by MALDI‐TOF mass spectrometry. In all products (with the exception of 2,4,6‐trimethylpyridine‐catalyzed samples) cyclic oligo‐ and polycarbonates (identified up to masses around 15 000 Da) were found. Their content was particularly high when 4‐(dimethylamino)pyridine was used or when a neutral salt was added to pyridine catalyzed polycondensations. A higher temperature reduced both molecular weight and content of cycles regardless, if pyridine or ethyldiisopropylamine was used as the catalyst. Furthermore, equimolar amounts of bisphenol‐A and BABC were polycondensed in anhydrous dichloromethane using pyridine or ethyldiisopropylamine as the catalyst and HCl acceptors. In both cases low molar mass polycarbonates mainly consisting of even‐membered cycles were obtained. The reaction mechanisms are discussed. All results prove that both highly nucleophilic and highly basic tert‐amines can efficiently catalyze chain growth and cyclization, provided that the reaction conditions are accordingly optimized. Both chain growth and cyclization mainly occur in the organic phase.MALDI‐TOF mass spectrum of the polycarbonate prepared by pyridine promoted polycondensation of bisphenol‐A and BABC in dry CH2Cl2.magnified imageMALDI‐TOF mass spectrum of the polycarbonate prepared by pyridine promoted polycondensation of bisphenol‐A and BABC in dry CH2Cl2.