Thermal degradation behavior of polymethacrylates containing amine side groups

The thermal degradation behavior of polymethacrylates containing amine groups such as poly(N,N-diethyl aminoethyl methacrylate), PDEAEM, and poly(N-ethyl-m-tolyl-aminoethyl methacrylate), PMEET, has been studied using thermogravimetry coupled with infrared spectroscopy (TGA/FTIR). PDEAEM showed two degradation stages whereas PMEET displayed only one. The thermal degradation of PDEAEM initially takes place through ester cleavage of the polymethacrylate, generating volatile tertiary amines and alcohols and polymethacrylic anhydride in the remaining solid material. This is followed by further fragmentation of the modified polymeric chain formed. It was also observed that storage of the original polymer affected the thermal decomposition behavior of PDEAEM. The main thermal degradation pathway for PMEET is an immediate backbone chain scission to yield oligomers.     

Mechanism and kinetics of the crosslinking reaction between biopolymers containing primary amine groups and genipin

The reaction mechanism of chitosan, bovine serum albumin (BSA), and gelatin with genipin (a natural crosslinking reagent) was examined with infrared, ultraviolet–visible, and ¹³C NMR spectroscopies; protein‐transfer reaction mass spectrometry; photon correlation spectroscopy; and dynamic oscillatory rheometry. Two reactions that proceeded at different rates led to the formation of crosslinks between primary amine groups. The fastest reaction to occur was a nucleophilic attack on genipin by a primary amine group that led to the formation of a heterocyclic compound of genipin linked to the glucosamine residue in chitosan and the basic residues in BSA and gelatin. The second, slower, reaction was the nucleophilic substitution of the ester group possessed by genipin to form a secondary amide link with chitosan, BSA, or gelatin. A decreased crosslinking rate in the presence of deuterium oxide rather than water suggested that acid catalysis was necessary for one or both of the reactions to proceed. The behavior of the gel time with polymer concentration was consistent with second‐order gelation kinetics resulting from an irreversible crosslinking process, but was complicated by the oxygen radical‐induced polymerization of genipin that caused the gels to assume a blue color in the presence of air. The lower elastic modulus attained after a given time during crosslinking of the globular protein BSA as compared to the coiled protein gelatin, despite possessing more crosslinkable basic residues, demonstrated the importance of protein secondary and tertiary structures in determining the availability of sites for crosslinking with genipin in protein systems. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3941–3953, 2003     

Cationic polyelectrolytes. IV. Kinetic study of the reaction of acrylic polymers containing tertiary amine groups with halogenated compounds in dipolar aprotic solvents

The reaction kinetics of halogenated compounds with tertiary amine groups attached at an acrylic macromolecular chain have ben studied. Three acrylic polymers were used. Two of them have mainly a structural unit of N, N-dimethylaminopropylacrylamide and the third is poly(N,N-dimethylaminoethylmethacrylate). Dimethylformamide, dimethylacetamide, and dimethylsulfoxide (DMSO) were used as dipolar aprotic solvents. Benzyl chloride and allyl chloride were considered as halogenated compounds with increased reactivity. The reaction kinetics depend on the polymer and halogenated-compound structures as well as the nature of the solvent. In the most of the cases the reactions carried out on polymers are accompanied by self-accelerating processes, with the exception of DMSO, which obviously has normal second-order kinetics. The reaction of polymers containing units of N,N-dimethylaminopropylacrylamide are compared with one having a low molecular weight, for instance N,N′-bis(3-dimethylaminopropyl)glutaramide.     

Polymers with tertiary amine groups for drug delivery and bioimaging

Over the past decade, biopolymers have gained great interests especially in biomedicine due to their physical properties and/or chemical structures changes in response to external stimuli in a certain time frame or at a specific location. Among them,poly(β-amino ester)s, methacrylate-based block copolymers and polypeptide with tertiary amine groups have been extensively studied and exhibit pH sensitive properties due to the protonation of tertiary amine groups. The pH values in normal organs,tissues, and subcellular compartments are always different from those in pathological tissues. These interesting properties allow their applications in a variety of fields ranging from diagnosis and therapeutics of diseases. Here, we review the recent progress of poly(β-amino ester)s, methacrylate-based block copolymers and polypeptide with tertiary amine groups and their applications in drug delivery and bioimaging.     

Poly(urethaneimides) (PUIs) containing tertiary amine groups as precursors for original PUI cationomers

This paper details the synthesis and characterisation of poly(urethaneimides) (PUIs) containing tertiary amine groups and obtained from a polytetramethylene oxide diol (PTMO1000), N-methyldiethanolamine (MDEA), 4,4′-methylene-bis-phenylisocyanate (MDI) and 4,4′-hexafluoroisopropylidene-bis-phthalic anhydride (6FDA). The polymers PTMO1000 (1 − x equiv.) + MDEA (x equiv.)/MDI (2 equiv.)/6FDA (1 equiv.) were obtained in high yields (>90%) through original synthesis, involving the reaction of macrodiisocyanates with an aromatic dianhydride in two steps only. A wide range of complementary techniques including two-dimensional NMR showed that the new method enabled a very good control of the polymer structure. In particular, the tertiary amine content of the PUI copolymers was easily varied over the whole composition range (x: 0 → 1), with interesting prospects for the design of a wide range of ion-containing poly(urethaneimides) by quaternising the tertiary amine groups. The PUI properties (e.g. solubility, viscosity, film-forming ability, etc.) clearly depended upon their tertiary amine content. Up to a tertiary amine content of x = 0.7 equiv., the very good film-forming character of the PUIs enabled to cast strong films suitable for permeability investigations.     

Benzylation of hydroxy groups with tertiary amine as a base

The benzylation of hydroxy groups in the presence of tertiary amines is described. A mixture of an alcohol and a benzyl halide afforded the corresponding benzyl ether in good to excellent yields in the presence of diisopropylethylamine. The importance of solventless conditions was observed. The reaction showed high tolerance to many functional groups including benzoate, even at a reaction temperature of 150 °C. Sodium iodide was found to be an efficient catalyst to accelerate the reaction.     

Spectrophotofluorometric determination of some alkaloids containing a tertiary amine group

The method developed involves the base-catalysed condensation of mixed anhydrides of organic acids, where a tertiary amine group functions as the basic catalyst. The product of the condensation reaction is highly fluorescent and allows the fluorometric determination of alkaloids containing a tertiary amine group, in the ng ml range. The mixed anhydride system is simple to prepare and the fluorogenic reaction is completed within 15 min at 80 degrees . The reaction is specific for, but does not distinguish between, different tertiary amines.     

Oxidation‐assisted structural elucidation of compounds containing a tertiary amine side chain using liquid chromatography mass spectrometry

A novel analytical technique for the structural elucidation of compounds bearing a tertiary amine side chain via “in vial” instantaneous oxidation and liquid chromatography mass spectrometry (LC‐MS) was developed. A series of lidocaine homologs and benzimidazole derivatives with a major/single amine representative base peak in both their EI‐MS and ESI‐MS/MS spectra were subjected to oxidation by a 0.1% solution of hydrogen peroxide (including several ¹⁶O/¹⁸O exchange experiments), followed by LC‐ESI‐MS/MS analysis. The N‐oxide counterparts promoted extensive fragmentation with complete coverage of all parts of the molecule, enabling detailed structural elucidation and unambiguous identification of the unoxidized analytes at low nanogram per milliliter levels.     

Preparation, characterization, and application of a new stationary phase containing different kinds of amine groups

A new stationary phase containing primary amine and tertiary amine groups was synthesized and its structure was confirmed by infrared spectra, elemental analysis, and zeta potential. This new material was packed into a stainless steel column and the effect of acetonitrile (ACN) content in mobile phase on retention was evaluated using probes of nucleosides, sulfanilamides, and quinolone compounds. This showed hydrophilic interaction, ion interaction, or a mixed-mode retention mechanism for different kinds of solutes, respectively. The effects of the pH and ion strength of the mobile phase were investigated to further understand the retention mechanism of the new stationary phase. The interaction forces caused by the new phase included adsorption, electrostatic function, and ion exchange. The new material could be used as a stationary phase in different high-performance liquid chromatography modes.     

Synthesis and photopolymerization kinetics of multifunctional aromatic urethane acrylates containing tertiary amine group

Two multifunctional aromatic urethane acrylates, based on 2, 4‐toluene diisocyanate (2, 4‐TDI), β‐hydroxyethyl arcylate (HEA), and synthetic multifunctional hydroxyl compounds, were synthesized by classical condensation reaction. FTIR was used to monitor the process of the reaction. The photopolymerization kinetics of the urethane acrylates with different photoinitiators was studied by Real‐Time Infrared Spectroscopy. The results indicated that different from the commercial urethane acrylate CN 975, the synthetic multifunctional urethane acrylates could be efficiently initiated by BP without the addition of any co‐initiators as they have tertiary amine structures. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of glycols in glycol-containing oligomers using gas-liquid reaction chromatography

A method is proposed for the gas-chromatographic determination of glycols as bis(diethoxyphosphoryl) alkanes formed by the Atherton–Todd reaction with diethyl phosphite. Gas-chromatographic and mass-spectrometric characteristics of the derivatives obtained are studied. Conditions of the phosphorylation reaction are optimized. The method is applied to the determination of the residual amounts of glycols in oligomeric glycol-o-phthalates.     

1,2,3-Triazole as a safer and practical substitute for cyanide in the Bruylants reaction for the synthesis of tertiary amines containing tertiary alkyl or aryl groups

Tertiary amines containing tertiary alkyl or aryl groups were synthesized by the reaction of a ketone with an amine and 1,2,3-triazole followed by substitution of the triazole adduct with a Grignard reagent. Thus, 1,2,3-triazole serves as a safer and practical alternative to cyanide in the Bruylants reaction.     

含有两个香豆素的α,ω-双发色团长链化合物的光环合加成反应

本文研究了含有两个香豆素的α,ω双发色团长链化合物在溶液中的光环合加成反应, 结果表明: 标题化合物有着不同于单体香豆素的光化学行为, 即它能在低浓度及非极性溶剂内发生分子内的光二聚反应。此外, 通过高分辨核磁共振谱对产物立体化学的研究发现, 反应无论是在极性溶剂或非极性溶剂中进行或反应中是否加入了三重态敏化剂。所得产物均为顺式头-头分子内二聚结构。对反应机制进行了初步讨论。     

Synthesis and characteristics of novel chelate fiber containing amine and amidine groups

A polyacrylonitrile (PAN) fiber was adopted for the backbone of a chelate polymer and poly(acrylo‐amidino ethylene amine) (PAEA) was prepared through a one‐step reaction between the PAN fiber and ethylenediamine (EDA). The maximum removal capacity and degree of substitution were 7.8 meq per gram of dried PAEA and 98%, respectively. The PAEA was tested as an adsorbent in single and two‐component metal aqueous solutions under changing pH. The Cu²⁺ ion accomplished maximum adsorption amount at pH 3 and the order of maximum adsorbed amounts on PAEA is Cu²⁺ > Ag⁺ > Zn²⁺ > Ni²⁺ > Pb²⁺ in molar basis. FT‐IR spectroscopy was employed to characterize the chemical bonding in metal aqueous solutions and surface morphology was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Copyright © 2004 John Wiley & Sons, Ltd.     

Measurement of the adduction constant by gas-liquid chromatography

Summary The adduction constants for the following eight binary systems were measured by gas liquid chromatography, at different temperatures: tetrachloromethane/p-xylene, tetrachloromethane/pseudocumene, chloroform/p-xylene, chloroform/pseudocumene, chloroform/aniline, m-methylphenol/aniline, o-methylphenol/aniline, and o-chlorophenol/aniline. The relationships between the adduction constant and temperature were used to fit the enthalpies and entropies of adduct formation.