Application of 1-Allyl-3-(1-butyl)imidazolium Chloride in the Synthesis of Cellulose Esters: Properties of the Ionic Liquid, and Comparison with Other Solvents

The ionic liquid (IL), 1-allyl-3-(1-butyl)imidazolium chloride (AlBuImCl), has been synthesized and its properties determined. Increase in the temperature increased its conductivity and decreased its density, polarity, and viscosity. Microcrystalline cellulose (MCC), dissolves in thisIL by heating at 80 degrees C; this did not affect its degree of polymerization, decreased its index of crystallinity (Ic), and changed in morphology after regeneration. Convenient acylation of MCC was achieved by using 50% excess anhydride at 80 degrees C, for 24 or 48 h for acetic and butyric anhydride, respectively. The composition of the mixed esters depended on the initial ratio of the anhydrides, and their order of addition.

Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether, lithium perchlorate, and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Raman spectra of polymer electrolytes based on poly(ethylene glycol) dimethyl ether (PEGdME) with LiClO(4), PEGdME/LiClO(4), and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, PEGdME/[bmim]PF(6), are compared. Raman spectroscopy suggests stronger interactions in PEGdME/LiClO(4) than PEGdmE/[bmim]PF(6), thus corroborating previous results obtained by molecular dynamics simulations. Quantum Chemistry methods have been used to calculate vibrational frequencies and the equilibrium structure of segments of the polymer chain around the cation. A consistent picture has been obtained from Raman spectroscopy, density functional theory (DFT) calculations, and molecular dynamics simulations for these polymer electrolytes. (C) 2010 Elsevier B.V. All rights reserved.

Evaluation of Postpolymerization as a Function of the Storage Time of Triethylene Glycol Dimethacrylate/2,2-Bis[4-(2-Hydroxy-3-Methacryloxy-Prop-1-Oxy)-Phenyl]-propane Bisphenyl-alpha-Glycidyl Ether Dimethacrylate Copolymers Used in Dental Resins by Differential Scanning Calorimetry and Dynamic Mechanical Analysis

The aim of this work was to evaluate the effect of the storage time on the thermal properties of triethylene glycol dimethacrylate/2,2-bis[4-(2-hydroxy-3-methacryloxy-prop-1-oxy)-phenyl]propane bisphenyl-alpha-glycidyl ether dimethacrylate (TB) copolymers used in formulations of dental resins after photopolymerization. The TB copolymers were prepared by photopolymerization with an Ultrablue IS light-emitting diode, stored in the dark for 160 days at 37 degrees C, and characterized with differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and Fourier transform infrared spectroscopy with attenuated total reflection. DSC curves indicated the presence of an exothermic peak, confirming that the reaction was not completed during the photopolymerization process. This exothermic peak became smaller as a function of the storage time and was shifted at higher temperatures. In DMA studies, a plot of the loss tangent versus the temperature initially showed the presence of two well-defined peaks. The presence of both peaks confirmed the presence of residual monomers that were not converted during the photopolymerization process. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 679-684, 2009

H-1-N-15 NMR studies of the complex bis(S-allyl-L-cysteinate)palladium(II)

H-1-N-15 2D NMR data for S-allyl-L-cysteine (deoxyalliin) and for bis(S-allyl-L-cysteinate)palladium(II) complex are presented in this manuscript. Large upfield N-15 NMR shift of the amine nitrogen in the spectrum of the complex when compared to the spectrum of the ligand shows clearly coordination of S-allyl-L-cysteine, in the anion form, to palladium(II) through the NH2 group. (c) 2005 Elsevier B.V. All rights reserved.

Spectroscopy and electrochemical characterization of Langmuir-Blodgett and physical vapor thin films of 29-membered diazocrown ether 1 with two n-octyl substituents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ether-A -go-go 1 (Eag1) Potassium Channel Expression in Dopaminergic Neurons of Basal Ganglia is Modulated by 6-Hydroxydopamine Lesion

The ether A go-go (Eag) gene encodes the voltage-gated potassium (K+) ion channel Kv10.1, whose function still remains unknown. As dopamine may directly affect K+ channels, we evaluated whether a nigrostriatal dopaminergic lesion induced by the neurotoxin 6-hydroxydopamine (6-OHDA) would alter Eag1-K+ channel expression in the rat basal ganglia and related brain regions. Male Wistar rats received a microinjection of either saline or 6-OHDA (unilaterally) into the medial forebrain bundle. The extent of the dopaminergic lesion induced by 6-OHDA was evaluated by apomorphine-induced rotational behavior and by tyrosine hydroxylase (TH) immunoreactivity. The 6-OHDA microinjection caused a partial or complete lesion of dopaminergic cells, as well as a reduction of Eag1+ cells in a manner proportional to the extent of the lesion. In addition, we observed a decrease in TH immunoreactivity in the ipsilateral striatum. In conclusion, the expression of the Eag1-K+-channel throughout the nigrostriatal pathway in the rat brain, its co-localization with dopaminergic cells and its reduction mirroring the extent of the lesion highlight a physiological circuitry where the functional role of this channel can be investigated. The Eag1-K+ channel expression in dopaminergic cells suggests that these channels are part of the diversified group of ion channels that generate and maintain the electrophysiological activity pattern of dopaminergic midbrain neurons.

Application of primary allyl amines afforded by the Baylis-Hillman adducts for heterocyclic synthesis: Generation of 5-benzyl-4(3H)-pyrimidinones and 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones

The applications of the primary allyl amines afforded by the acetyl derivative of Baylis-Hillman adducts of acrylate for the synthesis of heterocycles using robust reactions are described. In the first strategy a one-pot synthesis of 5-benzyl-4(3H)-pyrimidinones have been achieved via N-formylation of the amines in the presence of neat formamide followed by ammonium formate-mediated cyclization. These pyrimidinones have been demonstrated to be excellent precursor to the 4-pyridinamine derivatives. In the second strategy the synthesis of 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones have been accomplished via treatment of allyl amine with dimethoxyfuran followed by saponification and PPA-mediated intramolecular cyclization.

Radio control. Hearings before the Committee on interstate commerce, United States Senate, Sixty-ninth Congress, first session, on S. 1 and S. 1754, bills reaffirming the use of the ether for radiocommunication or otherwise to be the inalienable possession of the people of the United States and their government, providing for the regulation of radiocommunication, and for other purposes.

Hearings held Jan. 8.-Mar. 2, 1926.

An ESR study of irradiated poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA)

Poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) with 2 mol% perfluoropropyl vinyl ether (PPVE) was exposed to γ-irradiation in vacuum at both 77 K and room temperature and the ESR spectra recorded. Both the main chain, CF2–C.F–CF2, and end chain, CF2C.F2 radicals were identified at both temperatures and their thermal stabilities measured. No radicals unique to the radiolytic cleavage at the PPVE units were observed at room temperature, either due to the low concentration of the comonomer or β-scission to form a chain end radical and a non-radical species. G-values for radical formation at room temperature and 77 K were found to be 0.93 and 0.16, respectively.

Polybrominated diphenyl ether (PBDE) concentrations decrease with age : analysis of pooled human blood serum in the Australian population

Introduction Polybrominated diphenyl ethers (PBDEs) are considered to be a cost effective and efficient way to reduce the possibility of product ignition and inhibit the spread of fire, thereby limiting harm caused by fires. PBDEs are incorporated into a wide variety of manufactured products and are now considered an ubiquitous contaminant found worldwide in biological and environmental samples1 . In comparison to “traditional” persistent organic pollutants (POPs), the exposure modes of PBDEs in humans are less well defined, although dietary sources, inhalation (air/particulate matter) and dust ingestion have been reported 2-4. Limited investigations of population specific factors such as age or gender and PBDE concentrations report: no conclusive correlation by age in adults; higher concentrations in children ; similar concentrations in maternal and cord blood; and no gender differences. After preliminary findings of higher PBDE concentrations in children than in adults in Australia11 we sought to investigate at what age the PBDE concentrations peaked in an effort to focus exposure studies. This investigation involved the collection of blood samples from young age groups and the development of a simple model to predict PBDE concentrations by age in Australia.

Synthesis of discrete allyl-functional polyethylene glycol for efficient hydrophilization of dihydr (polydimethylsiloxane)

Amphiphilic poly(ethylene glycol)-block-pol (dimethylsiloxane)-block-poly(ethylene glycol)(PEG-block-PDMS block-PEG) triblock copolymers have been successfully prepared via hydrosilylation using discrete and polydisperse PEG of various chain lengths. Facile synthesis of discrete PEG (dPEG) is achieved via systematic tosylation and etherification of lower glycols. Amphiphilicity of the dPEG block-PDMS-block-dPEG triblock copolymer is illustrated by dynamic light scattering (DLS) and measurement of the critical micelle concentration (CMC).

Molecular cocrystals of 5-(4-bromophenyl)-1,3,4-thiadiazol-2-amine: hydrogen bonding in the structures of the 1:1 adduct with 2-(naphthalen-2-yloxy)acetic acid and the salt with 3,5-dinitrobenzoic acid

The structures of the anhydrous products from the interaction of 2-amino-5-(4-bromophenyl)-1,3,4-thiadiazole with (2-naphthoxy)acetic acid, the 1:1 adduct C8H6BrN3S . C12H10O3 (I) and 3,5-dinitrobenzoic acid, the salt C8H7BrN3S+ C7H3N2O6- (II) have been determined. In the adduct (I), a heterodimer is formed through a cyclic hydrogen-bonding motif [graph set R2/2(8)], involving carboxylic acid O-H...N(hetero)and amine N-H...O(carboxyl) interactions. The heterodimers are essentially planar with a thiadiazole to naphthyl ring dihedral angle of 15.9(2)deg. and the intramolecular thiadiazole to phenyl ring angle of 4.7(2)deg. An amine N-H...N(hetero) hydrogen bond between the heterodimers generates a one-dimensional chain structure extending down [001]. Also present are weak benzene-benzene and naphthalene-naphthalene pi-pi stacking interactions down the b axis [minimum ring centroid separation, 3.936(3) Ang.]. With the salt (II), the cation-anion association is also through a cyclic R2/2(8) motif but involving duplex N-H...O(carboxyl) hydrogen bonds, giving a heterodimer which is close to planar [dihedral angles between the thiadiazole ring and the two benzene rings, 5.00(16)deg. (intra) and 7.23(15)deg. (inter)]. A secondary centrosymmetric cyclic N-H...O(carboxyl) hydrogen-bonding association involving the second amino H-atom generates a heterotetramer. Also present in the crystal are weak pi-pi i-\p interactions between thiadiazolium rings [minimum ring centroid separation, 3.936(3)Ang.], as well as a short Br...O(nitro) interaction [3.314(4)Ang.]. The two structures reported here now provide a total of three crystallographically characterized examples of co-crystalline products from the interaction of 2-amino-5-(4-bromophenyl)-1,3,4-thiadiazole with carboxylic acids, of which only one involves proton-transfer.

The acetal concept : regioselective access toortho,ortho-diphenols via dibenzo-1,3-dioxepines

Traditional methods are ill-suited for the synthesis of ortho,ortho-biphenols, a structural motif found in many polyphenolic natural products, as well as synthetically useful compounds such as the chiral ligands binol, vapol, and vanol. The new route consists of a radical-based reaction of an acetal-tethered biphenyl ether substrate and subsequent hydrolytic cleavage of the dibenzo-1,3-dioxepine intermediate.