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Amine Moieties (amine + moiety)
Selected AbstractsLayered Double Hydroxide Surface Modified with (3-aminopropyl)triethoxysilane by Covalent Bonding,ADVANCED MATERIALS, Issue 1 2005A.-Y. Park Interlayer surfaces of layered double hydroxide (LDH) have been functionalized with amine moieties by condensation between the hydroxyl groups and (3-aminopropyl)triethoxysilane (APS) molecules via the covalent oxane bonds M-O-Si (M=Zn and Cr) (see Figure). Since the galleries of the modified LDHs have a hydrophobic field, various functional molecules such as enzymes, catalysts, and organic molecules can be incorporated between the LDH layers. [source] Gold nanoparticle-incorporated core and shell crosslinked micelles fabricated from thermoresponsive block copolymer of N -isopropylacrylamide and a novel primary-amine containing monomerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2008Yueming Zhou Abstract A novel primary amine-containing monomer, 1-(3,-aminopropyl)-4-acrylamido-1,2,3-triazole hydrochloride (APAT), was prepared from N -propargylacrylamide and 3-azidopropylamine hydrochloride via copper-catalyzed Huisgen 1,3-dipolar cycloaddition (click reaction). Poly(N -isopropylacrylamide)- b -poly(1-(3,-aminopropyl)-4-acrylamido-1,2,3-triazole hydrochloride), PNIPAM- b- PAPAT, was then synthesized via consecutive reversible addition-fragmentation chain transfer polymerizations of N -isopropylacrylamide and APAT. In aqueous solution, the obtained thermoresponsive double hydrophilic block copolymer dissolves molecularly at room temperature and self-assembles into micelles with PNIPAM cores and PAPAT shells at elevated temperature. Because of the presence of highly reactive primary amine moieties in PAPAT block, two types of covalently stabilized nanoparticles namely core crosslinked and shell crosslinked micelles with ,inverted' core-shell nanostructures were facilely prepared upon the addition of glutaric dialdehyde at 25 and 50 °C, respectively. In addition, the obtained structure-fixed micelles were incorporated with gold nanoparticles via in situ reduction of preferentially loaded HAuCl4. High resolution transmission electron microscopy revealed that gold nanoparticles can be selectively loaded into the crosslinked cores or shells, depending on the micelle templates employed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6518,6531, 2008 [source] Synthesis of well-defined glycidyl methacrylate based block copolymers with self-activation and self-initiation behaviors via ambient temperature atom transfer radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2007Ping Jiang Abstract Well-defined glycidyl methacrylate (GMA) based di- and triblock copolymers, with self-activation and self-initiation behaviors by incorporation of 2-(diethylamino) ethyl methacrylate (DEA) blocks, were synthesized via ambient temperature atom transfer radical polymerization (ATRP). The stability of the GMA pendant oxirane rings in tertiary amine environments at ambient temperature was investigated. More importantly, both self-activation behavior in oxirane ring opening addition reaction and self-initiation behavior in post-cure oxirane ring opening crosslinking of these block copolymers were evidenced by 1H NMR studies. The results demonstrated that the reactivity of pendent oxirane rings was strongly dependant on the nucleophilicity and steric hindrance of tertiary amine moieties and temperature. This facilitated the synthesis of well-defined block copolymers of GMA and DEA via sequential monomer addition ATRP, particularly for polymerization of GMA monomer at ambient temperature. Moreover, these one-component GMA based block polymers have novel self-activation and self-initiation properties, rendering some potential applications in both enzyme immobilization and GMA-based thermosetting materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2947,2958, 2007 [source] Antifungal and Antibacterial Activity of the Newly Synthesized 2-Xanthone DerivativesARCHIV DER PHARMAZIE, Issue 1 2009Henryk Marona Abstract A series of 2-substituted xanthone derivatives 8,20 containing selected allyl, cinnamyl, morpholine, and imidazole moieties were synthesized and tested for their antifungal and antibacterial in-vitro properties. Of the newly synthesized derivatives, ten revealed antifungal activity especially against Trichophyton mentagrophytes (the biggest inhibition zones ranged 35 mm for 11 and 13). 2-(3-(Allylamino)propoxy)-9H -xanthen-9-one hydrochloride 9 inhibited growth of all of the examined fungal species. Significant efficacy against evaluated yeasts and dermatophytes was also observed for 6-chloro-2-methyl-9H -xanthen-9-one derivatives 11,13 containing encyclic amine moieties. Additionally, compounds 9, 11, and 12 hindered development of bacteria species but in a lesser degree. They were efficacious against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis. [source] A Cyclam Core Dendrimer Containing Dansyl and Oligoethylene Glycol Chains in the Branches: Protonation and Metal CoordinationCHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2006Barbara Branchi Dr. Abstract We have synthesized a dendrimer (1) consisting of a 1,4,8,11-tetraazacyclotetradecane (cyclam) core, appended with four benzyl substituents that carry, in the 3- and 5-positions, a dansyl amide derivative (of type 2), in which the amide hydrogen is replaced by a benzyl unit that carries an oligoethylene glycol chain in the 3- and 5-positions. All together, the dendrimer contains 16 potentially luminescent moieties (eight dansyl- and eight dimethoxybenzene-type units) and three distinct types of multivalent sites that, in principle, can be protonated or coordinated to metal ions (the cyclam nitrogen atoms, the amine moieties of the eight dansyl units, and the 16 oligoethylene glycol chains). We have studied the absorption and luminescence properties of 1, 2, and 3 in acetonitrile and the changes taking place upon titration with acid and a variety of divalent (Co2+, Ni2+, Cu2+, Zn2+), and trivalent (Nd3+, Eu3+, Gd3+) metal ions as triflate and/or nitrate salts. The results obtained show that: 1) double protonation of the cyclam ring takes place before protonation of the dansyl units; 2) the oligoethylene glycol chains do not interfere with protonation of the cyclam core and the dansyl units in the ground state, but affect the luminescence of the protonated dansyl units; 3) the first equivalent of metal ion is coordinated by the cyclam core; 4) the interaction of the resulting cyclam complex with the appended dansyl units depends on the nature of the metal ion; 5) coordination of metal ions by the dansyl units follows at high metal-ion concentrations; 6) the effect of the metal ion depends on the nature of the counterion. This example demonstrates that dendrimers may exhibit complete functionality resulting from the integration of the specific properties of their component units. [source] N-methylation and N-formylation of a secondary amine drug (varenicline) in an osmotic tabletJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2008Kenneth C. Waterman Abstract Significant degradation of the amine-based smoking cessation drug varenicline tartrate in an early development phase osmotic, controlled-release (CR) formulation yields predominantly two products: N-methylvarenicline (NMV) and N-formylvarenicline (NFV). NMV is produced by reaction of the amine moiety with both formaldehyde and formic acid in an Eschweiler-Clarke reaction, while NFV is formed by reaction of formic acid alone with varenicline. This represents the first report of these reactions occurring on storage of solid pharmaceutical formulations. Both formaldehyde and formic acid are formed from oxidative degradation of polyethylene glycol (PEG) used in an osmotic coating through a process heavily dependent on the physical state of the PEG. When the concentration of PEG in the coating is sufficiently low, the PEG remains phase compatible with the other component of the coating (cellulose acetate) such that its degradation (and the resulting drug reactivity) is effectively eliminated. Antioxidants in the coating and oxygen scavengers in the packaging also serve to prevent the PEG degradation, and consequently provide for drug stability. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1499,1507, 2008 [source] Synthesis of amphiphilic and thermoresponsive ABC miktoarm star terpolymer via a combination of consecutive click reactions and atom transfer radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2009Changhua Li Abstract Well-defined amphiphilic and thermoresponsive ABC miktoarm star terpolymer consisting of poly(ethylene glycol), poly(tert -butyl methacrylate), and poly(N -isopropylacrylamide) arms, PEG(- b -PtBMA)- b -PNIPAM, was synthesized via a combination of consecutive click reactions and atom transfer radical polymerization (ATRP). Click reaction of monoalkynyl-terminated PEG with a trifunctional core molecule bis(2-azidoethyl)amine, (N3)2NH, afforded difunctional PEG possessing an azido and a secondary amine moiety at the chain end, PEG- NHN3. Next, the amidation of PEG- NHN3 with 2-chloropropionyl chloride led to PEG-based ATRP macroinitiator, PEG(N3)Cl. The subsequent ATRP of N -isopropylacrylamide (NIPAM) using PEG(N3)Cl as the macroinitiator led to PEG(N3)- b -PNIPAM bearing an azido moiety at the diblock junction point. Finally, well-defined ABC miktoarm star terpolymer, PEG(- b -PtBMA)- b -PNIPAM, was prepared via the click reaction of PEG(N3)- b -PNIPAM with monoalkynyl-terminated PtBMA. In aqueous solution, the obtained ABC miktoarm star terpolymer self-assembles into micelles consisting of PtBMA cores and hybrid PEG/PNIPAM coronas, which are characterized by dynamic and static laser light scattering, and transmission electron microscopy. On heating above the phase transition temperature of PNIPAM in the hybrid corona, micelles initially formed at lower temperatures undergo further structural rearrangement and fuse into much larger aggregates solely stabilized by PEG coronas. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4001,4013, 2009 [source] Maleimide-Modified Phosphonium Ionic Liquids: A Template Towards (Multi)Task-Specific Ionic LiquidsCHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2010Jocelyn Abstract The synthesis and characterization of several compounds representing a new class of multitask-specific phosphonium ionic liquids that contain a maleimide functionality is reported. The maleimide moiety of the ionic liquid (IL) is shown to undergo Michael-type additions with substrates containing either a thiol or amine moiety, thus, serving as a template to introduce wide structural diversity into the IL. Multitask-specific ILs are accessible by reaction of the maleimide with Michael donors that are capable of serving some function. As a model example to illustrate this concept, a redox active ferrocenyl thiol was incorporated and examined by cyclic voltammetry. Because the maleimide moiety is highly reactive to additions, the task-specific ionic liquids (TSILs) are prepared as the furan-protected Diels,Alder maleimide. The maleimide moiety can then be liberated when required by simple heating. [source] Copper-Catalyzed Asymmetric Conjugate Addition with Chiral SimplePhos Ligands,CHEMISTRY - A EUROPEAN JOURNAL, Issue 40 2009Laėtitia Palais Abstract SimplePhos ligands represent a novel class of monodentate chiral ligands based on a chiral amine moiety and flexible diaryl groups on the phosphorous atom. They can be easily prepared by two different pathways and they can be highly functionalised. Herein we report the copper-catalysed asymmetric conjugate addition of diethyl zinc and trialkylaluminium reagents with SimplePhos ligands, which gives high enantioselectivity with cyclic enones, acyclic enones and nitro-olefins, with up to 98.6,%,ee. Of particular interest is the reaction of trialkylaluminium reagents with a wide range of 3-substituted enones, thus allowing the formation of stereogenic quaternary carbon centres. [source] Theoretical and Experimental Study of the Adsorption of Neutral Glycine on Silica from the Gas PhaseCHEMPHYSCHEM, Issue 6 2005C. Lomenech Dr. Abstract The adsorption of neutral glycine onto amorphous silica was investigated both theoretically and experimentally. DFT calculations were performed at the BLYP-631++G** level using a cluster approach. Several possible configurations involving the formation of H bonds between glycine and one, two, or three silanol groups (SiOH) were considered. The most favorable bonding of glycine with one silanol group (45 kJ,mol,1) occurs through the COOH moiety, thus forming a cycle in which the CO group is an H-bond acceptor whereas the acidic OH group is an H-bond donor. With two or three silanol groups, additional H bonds are formed between the amine moiety and the silanol groups, which leads to an increased adsorption energy (70 and 80 kJ,mol,1for two and three silanol groups, respectively). Calculated ,CO, ,HNH, and ,HCHvalues are sensitive to the adsorption mode. A bathochromic shift of ,COas compared to the ,COof free glycine (calculated in the 1755,1790 cm,1range) is found for glycine in interaction with silanol(s). The more H bonds are formed between the COOH moiety and silanol groups, the higher the bathochromic shift. For ,HNH, no shift is found for glycine adsorbed on one and two silanol groups (where the amine is either not bound or an H-bond donor), whereas a bathochromic shift is calculated with three silanols when the amine moiety is an H-bond acceptor. Experimental FTIR spectra performed at room temperature for glycine adsorbed at 160,°C on Aerosil amorphous silica exhibit bands at 1371, 1423, 1630, and 1699 cm,1. The experimental/calculated frequencies have their best correspondence for glycine adsorbed on two silanol groups. It is important to note that the forms giving the best correspondence to experimental frequencies are the most stable ones. [source] | |||||||||||||