Replacement Of Chlorine Atoms Research Articles

A simple synthesis of natural spinazarins and their analogues

A short simple synthesis of spinazarins (2,3-dihydroxy-naphthazarins or 2,3,5,8-tetrahydroxy-1,4-naphtho-quinones) from available 2,3-dichloronaphthazarin derivatives involves replacement of chlorine atoms with azido groups followed by their acidic hydrolysis. The procedure can be used for the preparative synthesis of natural biologically active spinazarins and their analogues.

Curing of DER-331 Epoxy Resin with Arylaminocyclotriphosphazenes Based on o-, m-, and p-methylanilines.

As a result of this research, it was established that the chlorine atom replacement rates in hexa-chlorocyclotriphosphazene by o-, m-, and p-methylanilines' temperatures are crucial in determining which reaction is made. The speed of reaction practically does not affect the polarity of the synthesis solvent. For the formation of fully substituted o-, m-, and p-arilaminocyclotriphosphazenes, the reaction takes 5 h and is carried out in the diglyme at its boiling temperature. The structure of the synthesized AAP was confirmed by 31P and 1H NMR spectroscopy and MALDI-TOF mass spectrometry. By means of synchronous DSK and TGA, it is found that the synthesized AAP are crystalline and their thermal destruction has a stepped character. Thermal destruction is shown to be accompanied by the simultaneous removal of three aniline molecules from the AAP molecules. Conducted curing of epoxy resin DER-331 is carried out using the AAP as a curing agent. It has been established that due to steric difficulties, o- AAP does not interact with epoxy resin, unlike m- and p- AAP. The gel fraction in curing resin is measured, and the AAP relate to the stage processes of macromolecule formation. The result is that polymers based on DER-331 and m-, p-AAP have a gel fraction content up to 97 mass. %. These polymers have glass-transition temperatures 80 and 85 °C (m- and p-AAP-based, respectively) and demonstrate fire resistance to standard UL-94 of category V-0.

Nucleophilic Substitution at a Coordinatively Saturated Five-Membered NHC∙Haloborane Centre

In this paper, we have used a saturated five-membered N-Heterocyclic carbene (5SIDipp = 1,3-bis-(2,6-diisopropylphenyl)imidazolin-2-ylidine) for the synthesis of SNHC-haloboranes adducts and their further nucleophilic substitutions to put unusual functional groups at the central boron atom. The reaction of 5-SIDipp with RBCl2 yields Lewis-base adducts, 5-SIDipp·RBCl2 [R = H (1), Ph (2)]. The hydrolysis of 1 gives the NHC stabilized boric acid, 5-SIDipp·B(OH)3 (3), selectively. Replacement of chlorine atoms from 1 and 2 with one equivalent of AgOTf led to the formation of 5-SIDipp·HBCl(OTf) (4) and 5-SIDipp·PhBCl(OTf) (5a), where all the substituents on the boron atoms are different. The addition of two equivalents of AgNO3 to 2 leads to the formation of rare di-nitro substituted 5-SIDipp·BPh(NO3)2 (6). Further, the reaction of 5-SIDipp with B(C6F5)3 in tetrahydrofuran and diethyl ether shows a frustrated Lewis pair type small molecule activated products, 7 and 8.

Replacement of chlorine atoms in 3,6-di-tert-butyl-4,5-dichloro-o-benzoquinone in reactions with alkali metal gem-dithiolates. New o-quinones and their properties

Replacement of chlorine atoms in 3,6-di-tert-butyl-4,5-dichloro-o-benzoquinone in reactions with alkali metal gem-dithiolates. New o-quinones and their properties

EXPERIMENTAL EVALUATION OF TOXICOMETRIC INDICATORS AND ANALGESIC ACTIVITY OF KAPPA-OPIOID RECEPTOR AGONISTS

Data on the biological activity of kappa-opioid receptor agonists - derivatives of three groups of compounds: 1,2-cyclohexylamine, 1,2,3,4-piperidine, 1,2,4-piperazine are presented. On the examples of 1,2-cyclohexylamine and 1,2,4-piperazine derivatives, it has been shown that a decrease in the length of the carbon chain in the phenylalkyl substituent at the nitrogen atom is accompanied by a decrease in the analgesic activity and toxicity of compounds. The replacement of chlorine atoms in the 3 and 4 positions of the phenyl ring with fluorine atoms, which are more electronegative, leads to an increase in the analgesic effect and a decrease in the toxicity of the compounds.

Mass Spectrometry Reveals Complexing Properties of Modified PNP-Lariat Ether Containing Benzyl Derivative of (S)-Prolinamine.

In the investigation presented here the synthesis of new lariat ether derivative obtained from the modification of tetrapyrrolidinyl-PNP-crown ether macrocycle is described. The polyheterotopic molecular coreceptor consisted of the replacement of chlorine atoms with an optically active (S)-(1-benzylpyrrolidin-2-yl) methanamine. The structure was confirmed by using elemental analysis, mass spectrometry, and NMR spectroscopy. This work covers results concerning the complexing properties of the new ligand towards Ag+, Cu2+, Co2+, Ni2+, and Zn2+ ions. The formation of non-covalent complexes of 1:1 stoichiometry with the Cu2+, Co2+, Ni2+, and Zn2+ ions have been confirmed by mass spectrometry. Due to the previous work and application possibilities, a large emphasis was put on the investigation of the complexation ability of lariat ether with silver (I) cation to determine stability constants by direct potentiometric method. In this case, the formation of four different forms of complexes AgL, Ag2L, Ag3L, and Ag4L has been proved. The observed unusual binding through the nitrogen atoms from the exocyclic substituents may provide the structural unit to build a new coordination polymers.

IDENTIFICATION OF BIOMARKERS OF EXPOSURE AND EFFECT OF 1,4-DICHLOROHEXAFLUOROBUTENE-2

Using gas and high-performance liquid chromatography with mass-selective detection (GC/MS and HPLC/MS, respectively), the metabolism of previously unstudied freon RL316 (1,4-dichloro-1,1,2,3,4,4-hexafluorobutene-2, hereinafter - DCHF) has been investigated. Two volatile metabolites, which are products of reductive replacement of chlorine atoms: 1-chloro-1,1,2,3,3,4,4,4-octafluorobutane and 1-chloro-1,1,2,3,4,4-hexafluorobutene-2, have been detected and identified in the blood and urine samples of rats. In total 15 different previously unknown metabolites have been revealed and identified. The main direction of metabolism of DCHF is the formation of adducts with glutathione and their further degradation to cysteine and acetylcysteine adducts. Among all metabolites 4-methylsulfyl-1-chloro-1,1,2,3,4,4-hexafluorobutene-2, 4-methylsulfynyl-1-chloro-1,1,2,3,4,4-hexafluorobutene-2 and 1,1,3,4,4-pentafluoro-1,4-dichlorobutanethion-2 were found to be the most sensitive biomarkers. The intake of DCHF in the body does not lead to its bioactivation with the formation of labile thioketenes which are the main cause of mutagenic and carcinogenic effects of some halocarbons. Metabolic profiling of blood plasma revealed potential metabolic markers of exposure to D CHF at a concentration of 18,8 mg/ m 3 : the ratio of concentrations of gulonic acid and myo-inositol phosphate. The combination of the determination of the chemical markers - nonmetabolic forms of DCHF and 1,4-dichloro-1,1,3,4,4-butanthione-2 with the definition of discovered metabolic markers allows to estimate more accurately the dose or level of exposure of DCHF on the body of people in contact with it.

Oligomeric Hydroxyaryloxyphosphase Based on Resorcinol

By the reaction of hexachlorocyclosphosphazene with resorcinol in the immiscible pyridine–cyclohexane system, hexa-(m-hydroxyphenoxy)cyclotriphosphazene is synthesized, the optimum yield of which of 84% is achieved in a uniform mixture of the indicated solvents and the molar ratio HCP : resorcinol = 1 : 12. When used for the synthesis of oligomers mixtures of chlorocyclophosphazenes (PNCl2)n, where n = 3, 4, and 6, also complete replacement of chlorine atoms occurs, and with a yield of up to 80%, the formation of mixed oligohydroxyphenoxycyclophosphazenes takes place. The synthesized oligomers are characterized using 31P NMR spectroscopy and MALDI-TOF mass spectrometry.

Optimization of nucleophilic dechlorination of polychlorinated biphenyls: calculation and experiment

The nucleophilic substitution of aromatic chlorine atoms in polychlorinated biphenyls structures for non-toxic substituents was investigated. The reaction of industrial polychlorobiphenyls mixture Sovol with sodium methoxide in bipolar aprotic solvent was studied. Thermodynamic modeling and the HSC software were used to evaluate the reactivity of polychlorobiphenyls congeners from mixture Sovol toward sodium methoxide in dimethyl sulfoxide, and the calculation results were compared with experimental data. The reactivity of polychlorinated biphenyls was evaluated using gas chromatography and gas chromatography/mass spectrometry. Experimental and computational studies confirm that under the reaction conditions, the most reactive congeners are hepta-, hexa- and pentachlorobiphenyls, and the trichlorinated congeners represent the lowest reactivity. The tetrachlorobiphenyls possess an intermediate position. The optimal thermodynamic and chemical conditions at which occurs complete dechlorination of toxic chlorinated aromatic compounds under the conditions of nucleophilic substitution were proposed. The optimal conditions for the complete replacement of chlorine atoms in polychlorinated biphenyls congeners with methoxy groups were detected: temperature = 170 °C, ratio of polychlorinated biphenyls/sodium methoxide was 1:6 and reaction time was 4 h.

Chemical modifications of poly(vinyl chloride) to poly(vinyl azide) and “clicked” triazole bearing groups for application in metal cation extraction

Chemical modification of poly(vinyl chloride) (PVC) by the replacement of chlorine atom presents a considerable interest in this work. In the first phase, PVC was partially azided with a sodium azide. Click-chemistry based on Copper (I)-catalyzed Huisgen's reaction (CuAAC) was then used to form polymer-grafted 1,4-triazoles using some synthesized substituted alkynes. In the second phase, the new synthesized polymers were used in extraction studies of heavy metals (Cd, Cu, Ni and Pb). The obtained polymer-supported triazoles were characterized by infrared spectroscopy and thermal analysis (DSC). Evaluation of metallic cation extraction was done by atomic absorption of the remaining solutions. Three polymers efficiently removed Ni Cu and Pb with extraction yields between 50 and 90%. Two of the polymers studied had a high selectivity of extraction for Cadmium with a good efficiency (around 80%).

Syntheses, X-ray Crystal Structures and Intermolecular Interaction Patterns of Hydrazone Derivatives with 1,2,3-Triazole Entity at 100 K

Five new hydrazone derivatives, (E)-N′-(4-fluorobenzylidene)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbohydrazide, (E)-N′-(4-chlorobenzylidene)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbohydrazide, (E)-N′-(4-bromobenzylidene)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbohydrazide, (E)-N′-(4-hydroxy-3-methoxybenzylidene)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbohydrazide and (E)-N′-(1-(4-bromophenyl)ethylidene)-5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbohydrazide (denoted as A-E), were prepared and their molecular structures were characterized by single crystal X-ray diffraction. Compound A crystallizes in monoclinic P21/c, a = 6.8057(1) A, b = 12.7447(3) A, c = 18.6936(3) A, β = 105.356(1)°, B crystallizes in monoclinic P21/c, a = 8.3815(2) A, b = 20.8298(4) A, c = 9.5932(2) A, β = 99.612(1)°, C crystallizes in monoclinic P21/c, a = 8.4213(8) A, b = 21.077(2) A, c = 9.5899(10) A, β = 99.979(2)°, D crystallizes in monoclinic P21/c, a = 11.1644(10) A, b = 16.3508(15) A, c = 9.7313(9) A, β = 105.757(1)° and E crystallizes in triclinic $$P\bar{1}$$ , a = 8.7415(7) A, b = 10.1032(8) A, c = 11.6852(9) A, α = 68.306(1)°, β = 84.894(1)°, γ = 68.289(1)°. All of the five compounds with close molecular conformations adopt a trans configuration with respect to the hydrazone C = N double bond and weak non-classical intermolecular C–H···O hydrogen bonds are observed in the crystal. Isomorphous substitution between compounds B and C with simple replacement of chlorine atom to bromine atom is giving rise to similar molecular geometries, unit cell parameters and intermolecular interaction pattern of three-dimensional network. Five new hydrazone derivatives possessing 5-methyl-1-(4-nitrophenyl)-1,2,3-triazole moiety (denoted as A to E) are characterized by single crystal X-ray structure determination method. The intermolecular interaction pattern of D is strongly influenced by strong O–H···O hydrogen bond, whereas only non-classical C–H···O hydrogen bonds are observed in the rest. Compounds B and C with isomorphous chlorine-bromine substitution are crystallized under same space group and similar unit cell parameters.

Molecular complexes of l-phenylalanine with substituted 1,4-benzoquinones in aqueous medium: Spectral and theoretical investigations

Various spectral techniques such as UV–Vis, FT-IR, and fluorescence have been employed to investigate the charge transfer interaction of l-phenylalanine (LPA) with substituted 1,4-benzoquinones (MQ1–4). Kinetic and thermodynamic properties of the complexes were determined in aqueous medium at physiological condition (pH=7). The interaction of MQ1–4 with l-phenylalanine (LPA) was found to proceed through the formation of donor–acceptor complex, yielding a radical anion. The stoichiometry of the complexes was determined by Jobs continuous variation method and was found to be 1:1 in all the cases. Fluorescence quenching studies showed that the interaction between the donor and the acceptors is spontaneous. The results indicated that the progressive replacement of chlorine atom (−I effect) by methoxy group (+M effect) in the quinone decreased the electron acceptor property of the quinone. The order of the experimentally measured association constant of these complexes was well supported by DFT/B3LYP calculations.

Substituent effect on the electron acceptor property of 1,4-benzoquinone towards the formation of molecular complex with sulfamethoxazole

UV–Vis, 1H NMR, FT-IR, LC–MS and fluorescence spectral techniques were employed to investigate the mechanism of interaction of sulfamethoxazole with varying number of methoxy/chloro substituted 1,4-benzoquinones (MQ1–4) and to characterize the reaction products. The interactions of MQ1–4 with sulfamethoxazole (SULF) were found to proceed through the formation of a donor–acceptor complex, containing radical anion and its conversion to the product. Fluorescence quenching studies showed that the interaction between the donor and the acceptors are spontaneous. The results indicated that the progressive replacement of chlorine atom (−I effect) by methoxy group (+M effect) in the quinone decreased the electron acceptor property of the quinone. The results of the correlation of experimentally measured binding constants with electrochemical data and ab initio DFT calculations supported these observations.

Design and examination of an antioxidant-containing polyphosphazene scaffold for tissue engineering

Polyphosphazenes were synthesized that contained the antioxidant, ferulic acid, and amino acid esters as co-substituents. The synthesis protocol utilized the replacement of chlorine atoms in poly(dichlorophosphazene) by ferulic acid with either glycine, alanine, valine, or phenylalanine ethyl ester. Ferulic acid protects cells from free radical damage, and its steric characteristics have the potential to generate polymeric materials with high mechanical strength for hard tissue engineering scaffolds. Incorporation of the amino acid esters allows for control over the polymer hydrolysis while releasing the antioxidant at different rates. Macromolecular substitution reactions were carried out utilizing the allyl ester of ferulic acid to prevent side reactions during halogen replacement. The allyl protecting group was then removed using mild conditions. The polymers were characterized by 1H and 31P NMR, GPC, and DSC techniques. Static water contact angles were measured to monitor the change in hydrophobicity/hydrophilicity. Before deprotection, the water contact angles were 82–88° and after deprotection the water contact angles were 56–71°. A pH-dependent hydrolysis study revealed that the polymers are hydrolytically sensitive and decomposed ∼5–25% over 8 weeks yielding a final pH between 6.0–6.8. Polymer hydrolysis resulted in the release of ferulic acid. The polymers were photocrosslinked by a [2 + 2] cycloaddition of the ferulic acid moieties induced by exposure to long-wave UV light. The crosslinking was monitored by UV-spectroscopy via the apparent decrease in the 320 nm absorbance, attributed to the cyclization of the ferulic acid moieties. Increased UV exposure time led to an increase in the level of crosslinking. After 60 s, the polymers were crosslinked ∼41–62%. Hydrolysis experiments of the crosslinked materials showed only a 0–5% weight loss after 8 weeks with a pH between 6.6–7.0.

Synthesis and characterization of novel type poly (4-chloromethyl styrene-grft-4-vinylpyridine)/TiO2 nanocomposite via nitroxide-mediated radical polymerization

This paper describes the synthesis and characterization of novel type poly (4-chloromethyl styrene-graft-4-vinylpyridine)/TiO2 nanocomposite. Firstly, poly (4-chloromethyl styrene)/TiO2 nanocomposite was synthesized by in situ free radical polymerizing of 4-chloromethyl styrene monomers in the presence of 3-(trimethoxysilyl) propylmethacrylate (MPS) modified nano-TiO2. Thereafter, 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH) was synthesized by the reduction of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). This functional nitroxyl compound was covalently attached to the poly (4-chloromethyl styrene)/TiO2 with replacement of chlorine atoms in the poly (4-chloromethyl styrene) chains. The controlled graft copolymerization of 4-vinylpyridine was initiated by poly (4-chloromethyl styrene)/TiO2 nanocomposite carrying TEMPO groups as a macroinitiators. The coupling of TEMPO with poly (4-chloromethyl styrene)/TiO2 was verified using 1H nuclear magnetic resonance (NMR) spectroscopy. The obtained nanocomposites were studied using transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and the optical properties of the nanocomposites were studied using ultraviolet–visible (UV–Vis) spectroscopy.

Reactions of azoles with tetrachloro-1,2-difluoroethane and 1,2-dichlorodifluoroethylene

Tetrachloro-1,2-difluoroethane reacted with pyrazole and imidazole sodium salts to give mixtures of the corresponding N-(1,2,2-trichloro-1,2-difluoroethyl) derivatives and (E)-1,2-difluoro-1,2-dihetarylethenes. (E)-1,2-Difluoro-1,2-di(3,5-dimethyl-1H-pyrazol-1yl)ethene was also obtained as a result of replacement of chlorine atoms in 1,2-dichloro-1,2-difluoroethene. Analogous reaction with more nucleophilic imidazole involved replacement of not only chlorine but also fluorine atoms in 1,2-dichloro-1,2-difluoroethene, yielding tetraimidazolyl-substituted ethylene.

Synthesis of New (Pyrimido[4,5-e][1,3,4] thiadiazin-7-yl)hydrazine Derivatives

New (pyrimido[4,5-e][1,3,4]thiadiazin-7-yl)hydrazines were synthesized via the cyclocondensation of alkyl-2-phenylhydrazinecarbodithioates as bidentate nucleophiles with 5-bromo-2,4-dichloro-6-methylpyrimidine as an electrophile and further replacement of chlorine atom on the seven number position of pyrimido[4,5-e][1,3,4]thiadiazin by hydrazine in boiling ethanol.

Phthalocyanines and related compounds: XLVII. Nucleophilic replacement of chlorine atoms in tetrachlorophthalonitrile. Synthesis of phenyl(alkyl)amino-substituted phthalonitriles and some phthalocyanines based thereon

Nucleophilic replacement of chlorine atoms in tetrachlorophthalonitrile by the action of primary and secondary amines was studied. The reactions of tetrachlorophthalonitrile with amines at a ratio of 1: 10 gave with high yields and regioselectivity the corresponding 4,5-diamino-3,6-dichlorophthalonitriles from cyclic secondary amines and 4-amino-3,5,6-trichlorophthalonitriles from primary amines and acyclic secondary amines. 4-Amino-3,5,6-trichlorophthalonitriles were used to synthesize cobalt and zinc phthalocyanine complexes. It was shown that replacement of chlorine atoms in the pyrrolic β-positions of hexadecachlorophthalocyanines by amino groups is not accompanied by red shift of the long-wave absorption band in the electronic spectra.

Reactions of aniline in acetic acid solutions containing cyanuric chloride and hydrogen chloride acceptors

Two reaction pathways in acetic acid solution containing cyanuric chloride, aniline, and some hydrogen chloride acceptors (triethylamine, sodium acetate, pyridine) were studied. Both aryl amination and acylation can be performed with high yields under proper reaction conditions. Contrary to the only known literature report on the reactions between carbonic acids and cyanuric chloride in the presence of a hydrogen chloride acceptor (triethylamine), it was established that acid chlorides are not formed. A scheme involving the replacement of chlorine atoms by acetate ion in the initial stage was proposed for the acylation of aniline promoted by cyanuric chloride.Key words: acetic acid, acylation, aniline, cyanuric chloride, aryl amination.

2,5‐Dichloro‐4,4‐ethylenedioxy‐3‐phenylsulfonyl‐2‐cyclopentenone in Nucleophilic Substitution and Addition Reactions

AbstractFor Abstract see ChemInform Abstract in Full Text.