Effect of specific sorption of monomers in radical copolymerization of acrylamide with N,N-diethylacrylamide

The specific features of radical copolymerization of N,N-diethylacrylamide with acrylamide and the processes of diffusion of N,N-diethylacrylamide into the matrix of N,N-diethylacrylamide-acrylamide copolymers of various compositions were studied. The Huggins thermodynamic interaction parameters in the test copolymer-N,N-diethylacrylamide systems were determined and their dependence on the copolymer composition was obtained. It was shown that the type of this relation is determined by the effect of specific sorption of N,N-diethylacrylamide. An approach that makes it possible to take into account the effect of the specific binding of the blend components and to estimate their “true” local concentrations within the polymer coil was proposed.     

Determination of parameters of Mark-Kuhn-Houwink equations for poly-N-methacryloyloxyethyl-N,N,N-trimethylammonium methyl sulfate

The Mark-Kuhn-Houwink relationship was obtained for solutions of poly-N-methacryloyloxy-ethyl-N,N,N-trimethylammonium methyl sulfate in 1 M NaNO₃ from the light scattering and viscometric data. The Kuhn segment length for this polymer was estimated.     

Reactions of N,N-diethylhydrazine with formic and o-benzoylbenzoic acids

N,N-Diethylhydrazine reacted with formic acid at room temperature to give N,N-diethylhydrazinium formate which lost water molecule on heating to yield N′,N′-diethylformohydrazide. The reaction of N,N-diethylhydrazine with o-benzoylbenzoic acid gave a ionic-molecular salt-like complex including one N,N-diethylhydrazine molecule and two molecules of the acid that are held together through hydrogen bonds.     

Synthesis and characterization of thermally stable poly-N, N′-arylenebismaleimide

Three N,N′-arylenebismaleimides, viz. N,N′-m-phenylenebismaleimide, N,N′-p-phenylenebismaleimide and N,N′-benzidinebismaleimide, were prepared and polymerized in toluene using benzoyl peroxide (BPO) as initiator. The polymers obtained were characterized on the basis of elemental analysis and IR spectra. The polymers are insoluble in common organic solvents. The thermal behaviour of these polymers was studied by DTA and TG methods and the kinetic parameters order of reaction and activation energy were estimated.     

A study of tautomerism in N,N-dialkyl-4(5)-bromoalkanecarboxamides

N,N-Dialkyl-4-bromobutanamides exist in solution in tautomeric equilibrium with N,N-dialkyl-N-(tetrahydrofuran-2-ylidene)ammonium bromides, while related 4,5-dibromopentanamides show no similar interconversions with the corresponding iminium salts. A similar difference is observed when comparing the chemical behavior of their homologs, viz., N, N-dialkyl-5-bromopentanamide and N, N-dialkyl-5,6-dibromohexanamide     

Synthesis and transformations of bis(polychloroethylideneaminosulfonyl)- and bis(polychloroethylideneaminosulfonyl)-substituted derivatives of biphenyl, diphenyl oxide, and diphenylmethane

Reactions of N,N,N′,N′-tetrachlorobiphenyl-4,4′-disulfonamide, 4,4′-methylenebis(N,N-dichlorobenzenesulfonamide), and 4,4′-oxybis(N,N-dichlorobenzenesulfonamide) with 1,2-dichloroethylene and trichloroethylene open convenient synthetic approach to highly electrophilic bissulfony limines of dichloroacetic aldehyde and chloral: N,N′-bis(polychloroethylidene)biphenyl-4,4′-disulfonamides, 4,4′-methylenebis[N-(polychloroethylidene)benzenesulfonamides] and 4,4′-oxybis[N-(polychloroethylidene)benzenesulfonamides]. The synthetic opportunities of the bisazomethines obtained were demonstrated by examples of their reactions with water, methanol, chloroacetamide, and toluene where products of O-, N-nucleophiles addition to the azomethine bond and products of C-amidoalkylation of aromatic compound with imines were formed.     

New methods for preparing N,N-dialkyltrifluoroacetamides

N,N-Dialkylacetamides and N,N-dialkylformamides can be converted into N,N-dialkyltrifluoroacetamides by treatment with either trifluoroacetic anhydride or trifluoroacetic acid.     

A novel method for the one-pot conversion of carboxylic acids to N,N-dimethylamides

A simple, efficient, and new method has been developed for the preparation of N,N-dimethylamides from carboxylic acids. As described below, treatment of a variety of aromatic carboxylic acids with N,N-dimethylsulfamoyl imidazole or N,N-dimethylsulfamoyl chloride in the presence of a mixture of methanesulfonic acid/phosphorus pentoxide (2:1, v/w) proceeded effectively to afford the corresponding N,N-dimethylamides in moderate to good yields. This method is easy, rapid, and good yielding for the synthesis of N,N-dimethylamides from carboxylic acids.     

Specific features of rubber recovery from a latex with N,N-dimethyl-N,N-diallylammonium chloride under the action of magnetic field

The influence of the magnetic field intensity and treatment time on the efficiency of coagulation of SKS-30 ARK butadiene-styrene latex in the presence of a cationic electrolyte, N,N-dimethyl-N,N-diallylammonium chloride, was examined.     

Synthesis and structure of tris(4-N,N-dimethylaminophenyl)antimony(V) difluoride, dichloride, and dibenzoate

tris(4-N,N-Dimethylaminophenyl)antimony dichloride (I) was prepared by the reaction of tris(4-N,N-dimethylaminophenyl)antimony with copper dichloride. tris(4-N,N-Dimethylaminophenyl)antimony difluoride benzene disolvate II was synthesized from dichloride I and sodium fluoride in aqueous acetone with the subsequent crystallization from benzene. tris(4-N,N-Dimethylaminophenyl)antimony dibenzoate III was obtained from tris(4-N,N-dimethylaminophenyl)antimony and benzoic acid in the presence of hydrogen peroxide in ether or from silver benzoate and the corresponding dichloride in acetone. According to X-ray studies Sb atoms in two crystallographically independent molecules of dichloride, difluoride benzene solvate, and dibenzoate have the distorted trigonal bipyramide coordination [ClSbCl, FSbF, and OSbO trans angles are 178.12(2)°, 178.57(3)°, 177.30°, and 176.49° respectively). Sb-Cl, Sb-F, and Sb-O interatomic distances are 2.4719(7)-2.505(7); 2.106(4); 2.438(2); 2.1212(13) Å respectively. The oxygen atoms of carbonyl groups of the molecule III (C _2v molecular symmetry) are coordinated to the central atom [Sb-O distance 2.987(1) Å].     

Some analytical applications of aromatic sulfonyl haloamines: Estimation of indigocarmine by chloramine-B,bromamine-T,and dibromamine-T

Sodium N-chlorobenzenesulfonamide (chloramine-B, CAB), sodium N-bromo-p-toluenesulfonamide (bromamine-T, BAT) and N,N′-dibromo-p-toluenesulfonamide (dibromamine-T, DBT) are employed as analytical reagents for estimating indigocarmine (IC) in solution. A four-electron stoichiometry is observed within 30 min in the following media: CAB, 0.1–1.0 N HCl or H₂SO₄ and pH 1 buffer; BAT, 0.01–0.10 N NaOH; DBT, glacial acetic acid. The back titration methods are fairly rapid, simple, and accurate. The product of oxidation, isatinsulfonate, was estimated by spectrophotometric measurements at 410 nm. The sulfonamides formed by reduction of the haloamines are detected by TLC and paper chromatography.     

Complexation studies of Sn(II) by N,N-dimethylformamide and free energy of transfer of Sn(II) from acetonitrile to N,N-dimethylformamide

Studies of the complexation of Sn(II) by N,N-dimethylformamide show that Sn(II) ion forms six successive complexes with the ligand. The stability constants were determined by the method of DeFord and Hume. The free energy of transfer of Sn(II) from acetonitrile to N,N-dimethylformamide and to their mixtures was obtained using the theory of Cox et al. The energy decreases with increasing N,N-dimethylformamide concentration, the decrease being most pronounced for nearly pure acetonitrile.     

Über die Si3-N-bindung: XXXV. Darstellung von N-β-halogenäthyl-N,N-bis(trimethylsilyl)aminen

N-β-Haloethyl-N,N-bis(trimethylsilyl)amines, which can be used for the introduction of aminoethyl groups into organic or organosilicon compounds, are prepared in good yields from N-trimethylsilylaziridine and trimethylhalosilanes. This reaction is spontaneous with trimethylbromo- and -iodosilane, whereas it is necessary to run the reactions with trimethylchlorosilane in the presence of dipolar aprotic solvents and at higher temperatures.N-β-Bromoethyl-N,N-bis(trimethylsilyl)amine (II) is also obtained by silylation of N-β-bromoethylamine hydrobromide with trimethylsilyldiethylamine or with N-trimethylsilyl-N-methyl acetamide. Furthermore N-β-iodoethyl-N,N- bis(trimethylsilyl)amine is prepared by the reaction of II with MgI₂ or of aziridine and N-trimethylsilylaziridine respectively, with trimethylchlorosilane and MgI₂.From the silylation of N-β-bromoethylamine hydrobromide with trimethylsilyldiethylamine N,N-bis(trimethylsilyl)-N′,N′-diethylethylenediamine is isolated as a side product or, at higher temperatures, as the main product.     

The use of redox reactions in the analysis of dyes and dye industry intermediates: IV. Oxidation of benzidine,o-tolidine,and o-dianisidine with chloramine T and N-bromosuccinimide

The oxidation of benzidine, o-tolidine, and o-dianisidine with chloramine T and N-bromosuccinimide was studied, the stoichiometry was established, and a mechanism was proposed. An extraction-photometric determination of these diamines was developed, based on the reaction with excess chloramine T or N-bromosuccinimide and the measurement of the absorbance of the N,N′-dihalogeno-diphenoquinonediimines formed, after their extraction into chloroform.     

Studies of reactions of dimethylphosphoramidic difluoride withtrans-2-(N,N-dialkylamino)cycloalkanols in the presence of various sulfur-containing nucleophiles

The reactions of dimethylphosphoramidic difluoride (1) withtrans-2-(N,N-dialkylamino)cycloalkanols were studied in the presence of various sulfur-containing nucleophiles and Et₃N. WhenO,O-diisopropyl thiophosphoric acid was used as a nucleophile, the correspondingO,O-diisopropylS-[2-(N,N-dialkylamino)cycloalkyl] thiophosphates were obtained in satisfactory yields. The direction of this reaction in the presence ofO-isopropyl toluenephosphonothioic acid depends on the pK _a of aminoalcohol, namely, the amount ofO-isopropyl tolylphosphonofluoridate that was formed along withO-isopropylS-[2-(N,N-dialkylamino)cycloalkyl] tolylphosphonothioates was increased as the pK _a increased. The reactions of compound1 withtrans-2-(N,N-dialkylamino)cycloalkanols and thioacetic acid afforded 2-(N,N-dialkylamino)cycloalkanethiols, certain of which were readily oxidized to the corresponding disulfides. In the case of potassium ethyl xanthate, the composition of the reaction products depends on the nature of aminoalcohol. X-ray diffraction analysis ofS-(2-piperidinocyclohexyl)N,N-dimethyldithiocarbamate demonstrated that this compound exists as thetrans isomer. This fact supports the reaction mechanism, which we have suggested previously and which involves the formation of aziridinium cations followed by their opening under the action of nucleophilic agents.     

Ni-catalyzed arylation of bromomagnesium diarylamides with aryl N,N-dimethylsulfamates

The combination use of Ni(cod)₂ and N,N-1,3-bis(2,6-diisopropylphenyl)-4-imidazoline-2-ylidene as a catalyst successfully gave unsymmetrical N,N-diaryl-N′,N′-diphenyl-1,1′-biphenyl-4,4′-diamines through the arylation of bromomagnesium diarylamide with 1-(4′-diphenylamino-1,1′-biphenylyl) N,N-dimethylsulfamate. This Ni catalyst and Grignard reagents of diaryl or monoarylamides were also useful in the syntheses of various triarylamines and diarylamines from corresponding aryl N,N-dimethylsulfamates.     

Specific features of rubber recovery from latex with poly-N,N-dimethyl-N,N-diallylammonium chloride in the presence of cotton fiber

The effect of cotton fiber additions on the coagulating power of a cationic polyelectrolyte, poly-N,N-dimethyl-N,N-diallylammonium chloride, in rubber recovery from SKS-30 ARK latex was studied. The influence of the coagulating agent dosage and coagulation temperature on the completeness of the rubber recovery, with the polyelectrolyte introduced in the presence of cotton fiber and without it, was examined.     

Poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide as efficient reagents for synthesis of quinolines

Poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) [PBBS] and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] were used as efficient reagents for the synthesis of quinolines in excellent yields from 2-aminoaryl ketones and carbonyl compounds under aqueous and solvent-free conditions.     

Copolymerization in N-vinylcaprolactam-N-vinylpyrrolidone and N,N-diethylacrylamide-N,N-dimethylacrylamide systems: The effect of composition and spatial structure of copolymers on their thermal sensitivity

Factors that affect the temperature-responsive properties of water-soluble polymers were revealed by studying the copolymerization of two pairs of monomers: N-vinylcaprolactam-N-vinylpyrrolidone and N,N-diethylacrylamide-N,N-dimethylacrylamide. In each pair, the first monomer forms a temperature-responsive polymer and the second gives a polymer soluble in water up to the boiling point. It was found that in all cases, the addition of the second (more hydrophilic) monomer resulted in a monotonous increase in the phase separation temperature in an aqueous copolymer solution, with the temperature rise being comparatively slow in the initial stage and sharply accelerating after the addition of more than 40–50 mol % second monomer. The phase-separation temperature versus copolymer composition curves for N,N-diethylacrylamide-N,N-dimethylacrylamide copolymers of iso-and heterotactic structure synthesized via anionic polymerization are rather similar. At the same time, the copolymers of both types prepared via radical polymerization are characterized by steeper curves, a pattern that may be due to a high content of the syndiotactic structure, however, changes in the copolymer spatial structure have a lesser effect on the phase separation temperature than the presence of units of a more hydrophilic monomer. The addition of a relatively low amount (20–25 mol %) of a less hydrophilic monomer imparts temperature sensitivity to polymers, such as polyvinylpyrrolidone or polydimethylacrylamide, which do not possess this property in the pure form.     

Experimental and computational study of intermolecular migration of N,N-dimethylcarbamoyl group from N(7) to N(1) on a 7-azaindoline derivative

N,N-Dimethylcarbamoylation of the anilinic nitrogen atom N(1) on the spiro 7-azaindoline consists of two steps. The first step is N,N-dimethylcarbamoylation of the pyridyl nitrogen atom N(7), leading to the formation of an isolable intermediate. The second step is intermolecular migration of the N,N-dimethylcarbamoyl group from the pyridyl nitrogen atom N(7) to the anilinic nitrogen atom N(1). We accomplished optimization of the reaction conditions based on the revealed reaction mechanism and a large scale synthesis of compound 3 in quantitative yield.