Water-soluble 2-aminomethylidene-1,3-dicarbonyl compounds as new chalcogenide colloidal stabilizers

Reactions of 2-ethoxymethylidene derivatives of 1,3-dicarbonyl compounds with N,N-dimethylethane-1,2-diamine gave a number of 2-[(2-dimethylaminoethyl)amino]methylidene-1,3-dicarbonyl compounds which were subjected to regioselective quaternization at the tertiary nitrogen atom with methyl iodide. The resulting quaternary ammonium salts inhibited aggregation of cadmium and zinc sulfide sols in aqueous medium.     

Research on 1-azabicyclic systems

Epimeric 3-methylpyrrolizidines were separated preparatively. Competitive quaternization of the mixture of isomers with n-propyl iodide and catalytic isomerization were used to obtain trans-3, 8-H-3-methylpyrrolizidine. cis-3,8-H-3-Methylpyrrolizidine was isolated from the mixture by quaternization with benzyl chloride and subsequent hydrogenolysis of the resulting quaternary salt. The pK_a values of trans- and cis-3,8-H-3-methylpyrrolizidines, pyrrolizidine, and indolizidine were measured. It is shown that in a series of saturated amines with a tertiary nitrogen atom pyrrolizidine and 3-methylpyrrolizidines are among the strongest bases.See [1] for communication XII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1060–1064, August, 1976.     

聚砜阴离子交换膜的制备及结构与性能研究

以1,4-二氯甲氧基丁烷(BCMB)为氯甲基化试剂,使聚砜(PSF)发生氯甲基化反应,制得了氯甲基化聚砜(CMPSF),考察了主要因素对聚砜氯甲基化反应的影响,并使用FTIR及1H-NMR等法对CMPSF的化学结构进行了表征.采用三乙胺(TEA)、三丙胺(TPA)及三丁胺(TBA)等3种叔胺对CMPSF进行了季铵化反应,并以4,4′-联吡啶为交联剂实施了交联反应,制备了聚砜阴离子交换膜(PSFAEM).测定了交换膜PSFAEM的主要性能,包括离子交换容量(IEC)、含水量(WC)及膜电阻(Rm).实验结果表明,使用BCMB,聚砜的氯甲基化反应可顺利进行,以氯仿为溶剂,以SnCl4为Lewis酸催化剂,可制得氯甲基化程度为1.75mmol/g的CMPSF.交换膜PSFAEM的IEC、WC及Rm与季铵化反应时间及叔胺的种类密切相关.季铵化反应时间相同时,采用烷基中碳原子数少的叔胺TEA所制备的交换膜具有高的IEC与WC,低的Rm;使用同一种叔胺时,随季铵化反应时间的增长,交换膜的IEC与WC增大,Rm减小.     

Quaternization centers of N-methyl derivatives of imidazo[4,5-b]pyridine

It is shown that quaternization of isomers of 1-methylimidazo[4,5-b]pyridine and 3-methyl-imidazo[4,5-b]pyridine proceeds at different reaction centers — at the nitrogen atom of the imidazole ring in the first case and at the nitrogen atom of the pyridine ring in the second case.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1686–1688, December, 1973.     

Quaternization of poly(tertiary aminostyrene)s and characterization of the quaternized polymers

The Menschutkin reaction of three poly(tertiary aminostyrene)s: poly(N,N-dimethyl-4-vinylphenylamine) (PPA), poly(N,N-dimethyl-4-vinylbenzylamine) (PBA), and poly(N,N-dimethyl-4-vinylphenethylamine) (PPTA) was investigated. These three polymers having narrow molecular weight distributions were prepared via anionic living polymerization. PPA reacted homogeneously with n-butyl bromide in N,N-dimethylformamide (DMF). PBA and PPTA also reacted homogeneously with n-butyl bromide in a mixture of DMF/methanol (75/25 v/v %). GPC measurement of the quaternized polymers was carried out using a mixture of water/acetonitrile (80/20 v/v %) containing 0.5M acetic acid and 0.3M sodium sulfate (pH = 2.9) as an eluant in order to suppress adsorption of the quaternized water soluble polymers on GPC gel. Results of GPC measurement indicate that the polymer chains of the three poly(tertiary aminostyrene)s are neither severed nor crosslinked in the process of quaternization. Temperature dependence and reaction time dependence on the degree of quaternization (DQ) were studied for PPT, PBA, and PPTA. By altering reaction time and temperature, the DQ values of the three poly(tertiary aminostyrene)s could be controlled in the range from 0% to nearly 100%. Quaternization reactivity of the amino groups in the three polymers was found to decrease in the order, PPTA, PBA, and PPA. The differences in reactivity are thought to be attributable to the electron density on the nitrogen atom of the N,N-dimethylamino group, and steric hindrance in the vicinity of the nitrogen atom. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1219–1226, 1997     

Nucleophilicity and Basicity in the Quaternization of 4-Substituted Quinuclidines. Polar effects. Part III

The second order rate constants (k) for quaternization of thirty 4-substituted quinuclidines ( 1 ) by methyl iodide in methanol have been measured. The effects of the substituents on rate are relatively small and indicate an early transition state with little charge separation. They also indicate less involvement of the nitrogen atom, i.e. a looser transition state, for quaternization by allyl halides than for the less reactive propyl halides. The log k values of 4-substituted quinuclidines correlate moderately well with their pK_a values, the main reason being the imperfect correlation between nucleophilicity and basicity. The assumption that substituents exert equal effects on rates and equilibria is therefore only partly justified. Certain irregularities in the correlation can be attributed to a reduction of the nucleophilicity of nitrogen in 1 due to hydrogen bonding to the solvent methanol. Furthermore, quaternization is faster and responds more strongly to substituent effects in the aprotic solvent acetonitrile.     

Stereochemistry of the quaternization of 2- and 4-epimeric trans-1-alkyl-2-methyl-4-ethynyldecahydro-4-quinolols with alkyl halides

The quaternization of trans-1-alkyl-2-methyl-4-ethynyldecahydro-4-quinolols containing an equatorial 2-CH₃ group by means of methyl iodide proceeds with predominant axial incorporation of the methyl group, whereas quaternization of the corresponding trans-1,2-dimethyl-4-ethynyldecahydro-4-quinolols by means of ethyl and n-propyl iodide takes place with predominant equatorial incorporation of the alkyl group; the ratios of the stereoisomers in the products of forward and reverse quaternization are approximately identical. Methylation of amino alcohols with an axial 2-CH₃ group also leads to the predominant formation of epimers of the quaternary salts with an axial methyl group attached to the nitrogen atom, whereas the reverse quaternization of these amino alcohols proceeds nonstereoselectively to give an approximately equimolar mixture of the epimers of the quaternary salts.anslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 793–795, June, 1977.     

Synthesis, structure, and quaternization and complexation reactions of κSCS pincer palladium complexes having 3,5-pyridinediyl unit

The cyclopalladation of 3,5-bis(diphenylphosphinothioyl)pyridine afforded new κ³S,C,S-pincer palladium complexes with a σ-bond between Pd and 4C of the centered 3,5-pyridinediyl unit. By utilizing the quaternization and complexation ability of the pyridine imine nitrogen (N_py) atom, various new pincer-type complexes, including hetero-binuclear complexes, have been synthesized.     

Quaternarisation de l'atome d'azote de systemes tautomeres de la serie des oxo-4 thiazoles. Cycloadditions dipolaires 1,3 des thiazoles mesoioniques formes in situ

4-Hydroxythiazoles and N-acylimino 4-thiazolidinones show similar tautomeric behaviour to azlactones. However, the mechanism of their reaction with dimethylacetylenedicarboxylate or with ethyl vinyl ether differs fundamentally. In the thiazole series, the first step is the quaternization of the nitrogen atom. The mesoionic thiazole intermediate is then trapped by a second molecule of the dipolarophile.     

Synthesis and characterization of a novel well-defined comb-like ionomer

A novel well-defined comb-like ionomer with cations was synthesized by the combination of living anionic polymerization and atom transfer radical polymerization (ATRP). The synthetic approach involves the coupling reaction of polystyrene (PS) backbone bearing 1,1-diphenylethene (DPE) pendant groups with living polystyryllithium (PSLi), subsequent amine functionalization of the resulting 1,1-diphenylmethyl anions with 3-dimethylaminopropyl chloride (DMAPC), and quaternization of tertiary amino groups with hydrochloric acid. The comb-like ionomer was characterized by ¹H NMR, IR, GPC measurements and end-group titrition.     

Tuning of the properties of rhodopsin-based molecular switches

The modification of relevant chemical properties of rhodopsin-based molecular photoswitches is presented. We show how both the substituents present and the nitrogen atom quaternization are capable to change the wavelength of absorption and the thermal stability of the photoisomer. Adjusting these properties, the molecular switches could be turned into useful compounds for solar energy storage devices.     

New method for preparation of α-substituted acrylonitrile derivatives

The method for the preparation of α-substituted acrylonitrile derivatives by the quaternization of the nitrogen atom of both Me₂N groups in the corresponding substituted 3-(dimethylamino)propanal dimethylhydrazones followed by the Hoffman decomposition of the resulting diiodides was developed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1707–1709, September, 1999.     

New macrobicyclic triphosphazides and triphosphazenes formed by self-assembly of tripodal triazides with triphosphanes

The self-assembly of tris(3-azidobenzyl)amines with 1,1,1-tris[(diphenylphosphino)methyl]ethane via tripod-tripod coupling proceeds successfully to give chiral macrobicyclic triphosphazides. The heating of these macrobicyclic cages induces a remarkable stepwise triple extrusion of molecular nitrogen to afford tri-λ⁵-phosphazenes, which preserved the chiral, propeller-like topology of their precursors. The replacement of one benzylic arm by an ortho-phenethylic or propylenic one still allows the success of the self-assembly. However, the quaternization of the pivotal nitrogen atom of the triamine in the form of N-oxide prevented its coupling with the triphosphane.     

AB CROSSLINKED POLYURETHANES THROUGH IONIC CROSSLINKING: INFLUENCE OF CROSSLINKING NETWORKS ON PHYSICO CHEMICAL PROPERTIES

Isocyanate-terminated prepolymers were synthesized using poly(tetramethylene oxide)glycol of molecular weight 1000 (PTMG₁₀₀₀) with tolylene-2,4-diisocyanate (TDI). The prepolymers were chain extended with N-methyldiethanolamine (N-MDEA) to form polyurethanes containing tertiary nitrogen. These polyurethanes were crosslinked with bromine terminated polyurethane, poly(urethane-imide), and poly(urethane-siloxane) through the formation of cationomers at tertiary nitrogen sites across the backbone polyurethanes.

The crosslinked cationomeric polyurethanes were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), mechanical analyses, (static and dynamic), and static contact angles measurements. FTIR spectral studies confirms the formation of bromine terminated poly(urethane-imide) and poly(urethane-siloxane), as well as quaternization of the tertiary nitrogen which leads to crosslinking. A comparison of thermal stabilities of crosslinked polymers with respect to the chemical nature of bromine terminated prepolymers (BTP) indicates improved thermal stability for poly(urethane-imide) based ABCP. Stress-strain analysis shows high elongation values for poly(urethane-siloxane) and poly(urethane-imide) based ABCPs. Dynamic mechanical analysis reveals better damping for poly(urethane- siloxane) based AB crosslinked polymers.     

MECHANISM OF THE REACTION OF DIPHENYL N-BROMOSULFILIMINE WITH SULFIDES,PHOSPHINES AND TERTIARY AMINES

Abstract

The mechanism of the reactions of diphenyl N-bromosulfilimine (I) with such nucleophiles as sulfides, phosphines and tertiary amines was investigated. In the presence of water, (I) reacts with sulfides or phosphines to afford the corresponding sulfoxides or the phosphine oxides in moderate yields; however, the reaction with tertiary amine gave only the N-t-aminosulfilimine derivative. The effect of ring size in the reaction with cyclic sulfides suggests that the reaction proceeds via initial bromine transfer from the nitrogen atom to the sulfur atom of the cyclic sulfides followed by S_N2 type substitution of bromide on the sulfur atom of the cyclic sulfide with the sulfilimino group. The phosphine oxide obtained in the reaction of (I) with optically active methyl n-propyl phenyl phosphine was racemized but retained a small portion of the optical activity. In the case of tertiary amines, even 1,4-diazabicyclo-(2,2,2)-octane (DABCO), in which the back side of the nitrogen atom is blocked, reacted smoothly to afford the corresponding ammonium salts, suggesting the reaction to be of S_N2 type on the nitrogen atom of the sulfilimine.     

Optimization of reaction conditions for REM resin-bound quaternization reactions

A study into the effect of reaction variables on the quaternization of REM resin-bound tertiary amines was undertaken. The influence of resin matrix, solvent, reaction time, temperature, and amount of quaternization agent on the outcome of reaction was evaluated by reaction monitoring using (19)F NMR. The highest yields of tertiary amine products were seen when DMSO was used as reaction solvent in conjunction with a reaction time of 18 h at room temperature. The use of heating for extended reaction times tended to depress yields, indicating product cleavage during quaternization. Quaternization on PS-DVB resin was found to be more robust than reaction on PS-PEG matrices where yields were generally considerably lower than the observed conversions. DMSO was the most efficient reaction solvent for both resins despite poor swelling of the quaternization starting material.     

NMR spectroscopic investigation of multi-walled carbon nanotubes modified by amino groups

The results of the functionalization of multi-walled carbon nanotube surface by amines containing different substituents at the nitrogen atom, namely, primary n-hexylamine, secondary izadrine, and tertiary N-benzylmorpholine and dithiline, are presented. It was shown by NMR spectroscopy, thermal analysis, mass spectrometry, X-ray photoelectron spectroscopy, and elemental analysis that the interaction of primary and secondary amines with modified nanotubes results in the formation of a covalent bond with the nitrogen atom of amines, while the reactions with tertiary amines afford quaternary ammonium salts; diamine is attached covalently through both amine groups.     

Solution properties of well-defined 2-(dimethylamino)ethyl methacrylate-based (co)polymers: A viscometric approach

Well-defined poly(2-(dimethylamino)ethyl methacrylate)-based (co)polymers with various molar masses were synthesized by atom transfer radical polymerization (ATRP) using CuBr ligated with 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as catalyst, and ethyl 2-bromoisobutyrate (EBiB) or α-methyl, ω-(2-bromoisobutyrate) poly(ethylene glycol) (mPEG_x-BiB) as (macro)initiator. The solution properties of these (co)polymers were investigated by viscometry either in pure water or in concentrated buffer solutions. It comes out that reduced viscosity in pure water is strongly affected by the molar mass of poly(2-(dimethylamino)ethyl methacrylate) block but also by the quaternization degree of tertiary amino groups. In fact, a polyelectrolyte effect can only be detected when the charge density per macromolecule reaches a critical value either in terms of molar mass or quaternization degree. Fitting of viscometry data according to either Huggins or Fuoss and Fedors equation also allows calculating the intrinsic viscosity and approaching the overlap concentration.     

Etudes par RMN en serie heterocyclique–III. Non-equivalence magnetique et inversion de l'azote dans une serie d'heteocycles pentagonaux diazotes,pyrazolines-2 et 3, pyrazolidines et pyrazolidones

The non-equivalence of ethyl, benzyl and isopropyl groups fixed on nitrogen atoms in 2-and 3-pyrazolines, pyrazolidines and pyrazolidones depends on the assymetry existing in the molecule. The asymmetric centres are either a ring carbon atom, a quaternary nitrogen atom (protonation, quaternarization) or a tertiary nitrogen atom (slow nitrogen inversion). The nitrogen inversion process was observed only in the case of pyrazolidines (possibility of inversion at the two adjacent nitrogens) and of pyrazolidones (inversion of the ‘non-amidic’ nitrogen). The inversion is temperature-dependent and is affected by substituents.     

Quaternarisation de diméthyl-5,6 pyrazolidino[4,3-d )isoxazolines-2

We have determined the quaternization site of bicyclic molecules such as dimethyl-5,6 pyrazolidino[4,3-d]isoxazolines-2 containing two vicinal sp³ nitrogen atoms in a cycle and one sp² nitrogen atome in the other by spectral methods and by degradation of their corresponding iodomethylates. The quaternization takes place on one of the two sp³ nitrogen atoms and is controlled by steric effects.