Showing papers on "Ether published in 1996"
TL;DR: In this paper, the conductivity and phase structure of composite polyether-alkali metal salt solid electrolytes are analyzed and discussed and it is suggested that the competition between the Lewis base ether oxygens in the polyether chains and filler Lewis base centres in the complexation of alkali metal cations leads to the formation of different types of complexes and therefore to the modification of the polymer electrolyte ultrastructure.
229 citations
Patent•
26 Aug 1996
TL;DR: In this article, the polymerizable liquid-crystalline compounds of the general formula (I) Z?1-Y1-A 1-Y3-M-Y4-A2-Y2-Z2? in which the variables have the following meanings: Z1, Z2 are radicals with reactive groups which can bring about polymerization; Y1 - Y4 are a chemical single bond, oxygen, sulphur, -O-CO-, -CO-O-, -OCO-N, -NR-CO-NR-, or -NR
Abstract: The invention concerns polymerizable liquid-crystalline compounds of the general formula (I) Z?1-Y1-A1-Y3-M-Y4-A2-Y2-Z2? in which the variables have the following meanings: Z1, Z2 are radicals with reactive groups which can bring about polymerization; Y1 - Y4 are a chemical single bond, oxygen, sulphur, -O-CO-, -CO-O-, -O-CO-O-, -CO-NR-, -NR-CO-, -O-CO-NR-, -NR-CO-O- or -NR-CO-NR-, at least one of the groups Y?3 and Y4? meaning -O-CO-O-, -O-CO-NR-, -NR-CO-O- or -NR-CO-NR-; A1, A2 are C?2?-C30 spacers in which the carbon chain can be interrupted by oxygen in the ether function, sulphur in the thioetherfunction or by non-adjacent imino or C1-C4 alkylimino groups; M is a mesogenic group; and R is C1-C4 alkyl. The compounds and compositions containing them are distinguished by advantageous liquid-crystalline phase temperature ranges and can be used in optical display units and cholesteric liquid-crystalline colouring agents.
226 citations
TL;DR: The crystal structure of the ternary porcine lipase-colipase-tetra ethylene glycol monooctyl ether complex has been determined and it is shown that TGME acts as a substrate analog, thus possibly explaining the inhibitory effect of this nonionic detergent on emulsified substrate hydrolysis at submicellar concentrations.
198 citations
IBM1
TL;DR: In this article, the degree of branching for fluoro-terminated hyperbranched poly(ether ketones) with different degrees of branching has been determined based on 19F NMR.
Abstract: Hyperbranched poly(ether ketones), with a variety of chain end functional groups and controllable degrees of branching, are prepared by the polymerization of AB2, AB3, and AB4 monomers. It is found that the choice of A and B, or the incorporation of dendritic and linear units into the ABx monomer structure, dramatically affects the degree of branching. Depending on the structure of the monomer unit, degrees of branching ranging from 15 to 71% can be obtained. For determining the degree of branching for fluoro-terminated hyperbranched poly(ether ketones), a new technique based on 19F NMR has been developed. Evaluation of the physical properties of the hyperbranched poly(ether ketones) with different degrees of branching has shown that thermal properties are independent of macromolecular architecture but depend heavily on the nature of the chain end functional groups, with glass transition temperatures ranging from 97 to 290 °C. The solubility of the hyperbranched poly(ether ketones) is also shown to depend...
190 citations
TL;DR: A comparison study of Ether Cleavage Systems using data from Y2K and Y2M to evaluate the efficiency and efficiency of these systems against known barriers, such as high temperatures and high pressures.
190 citations
Patent•
12 Nov 1996TL;DR: In this paper, the subject monomeric units useful in reducing the modulus of hydrogels are disclosed, and they are especially useful in the formation of biomedical articles such as silicone hydrogel contact lenses.
Abstract: Monomeric units useful in reducing the modulus of hydrogels are disclosed. Silicone hydrogels including the subject monomeric units are especially useful in the formation of biomedical articles such as silicone hydrogel contact lenses. In formula (I), A is an activated unsaturated group; R and D independently are alkyl, alkylene or haloalkyl groups having 1 to 10 carbon atoms wherein said carbon atoms may include ether linkages therebetween; R1, R2, R3 and R4 are independently selected from: alkyl or haloalkyl groups wherein ether linkages may be included between carbon atoms; siloxane groups; and carbocyclic ring groups having from 6 to 18 carbon atoms; m is in integer from 1 to 500; n is an integer from 1 to 20; x and y are 0 or 1; z is 1 or 2; and x+y+z=3; so long as at least one of R1 or R2 is an alkyl group having from 1 to 10 carbon atoms.
182 citations
TL;DR: In this article, a series of aromatic ether diamines having different numbers of benzene rings, different amino-substituted positions and different moieties in their structures was synthesized and the glass transition temperature (T g ) values and thermoplasticity were studied by focusing on the chemical structures of their repeating structure units.
174 citations
TL;DR: In this article, various calixarene tetraalkyl ethers and a calix[4]arene pentaalkyl- ether substituted at the upper rim by the CMPO-like functional group were synthesized for the first time and their ability to extract europium, thorium, neptunium, plutonium and americium from aqueous HNO3 into methylene chloride or o-nitrophenyl hexyl ether was studied under various conditions.
Abstract: Various calix[4]arene tetraalkyl ethers and a calix[5]arene pentaalkyl ether substituted at the upper rim by the CMPO-like functional group –NH–C(O)–CH2–P(O)Ph2 as well as some linear model compounds have been synthesized for the first time. Their ability to extract europium, thorium, neptunium, plutonium and americium from 1 mol dm–3 aqueous HNO3 into methylene chloride or o-nitrophenyl hexyl ether was studied under various conditions. All the new oligomeric ligands, but especially the calixarene derivatives, are tremendously strong extractants compared with the commonly used CMPO [(N,N-diisobutylcarbamoylmethyl)octylphenylphosphine oxide]. Also in transport studies through supported liquid membranes their efficiency is higher than that of CMPO which shows lower transport rates even at a 10-fold concentration.
169 citations
TL;DR: In this paper, a method for synthesis of highly substituted imidazole libraries on solid support using an aldehyde, an amine and a 1,2-dione in the presence of NH4OAc is described.
166 citations
TL;DR: In this article, the authors show that the acidity of the alkyl chain is degraded by other microorganisms, which are capable of degrading sulphophenyl carboxylates.
Abstract: Linear alkylbenzene sulphonates are primarily attacked via a hydroxylation of the alkyl chain from the methyl group followed by β-oxidation. The alkyl chain is metabolized by pure cultures to give sulphophenyl carboxylates which accumulate in the medium. In mixed culture, other microorganisms are capable of degrading sulphophenyl carboxylates. Formation of ethylene glycol monosulphates as major products of alkyl ethoxy sulphates demonstrates that the ether bonds are cleaved. The bacteria involved in growing on the alkyl chain are unable to utilize the hydrophilic moiety. This hydrophilic moiety, in turn, is degraded by other microorganisms.
164 citations
Patent•
12 Nov 1996TL;DR: In this article, the subject monomeric units useful in reducing the modulus of low water polymeric silicone compositions are disclosed, and they are especially useful in the formation of biomedical articles such as low water silicone contact lenses.
Abstract: Monomeric units useful in reducing the modulus of low water polymeric silicone compositions are disclosed. Low water compositions including the subject monomeric units are especially useful in the formation of biomedical articles such as low water silicone contact lenses. In formula (I), A is an activated unsaturated group; R and D independently are alkyl, alkylene or haloalkyl groups having 1 to 10 carbon atoms wherein said carbon atoms may include ether linkages therebetween; M is hydrogen, fluorine, or an alkyl group; R1, R2, R3 and R4 are independently selected from: alkyl or haloalkyl groups wherein ether linkages may be included between carbon atoms; siloxane groups; and carbocyclic ring groups having from 6 to 18 carbon atoms; m is an integer from 1 to 500; n is an integer from 1 to 20; x and y are 0 or 1; z is 1 or 2; and x + y + z = 3; so long as at least one of R1 or R2 is an alkyl group having from 1 to 10 carbon atoms.
TL;DR: The discovery of the (alpha-L-alanyloxy)-methyl ether and hemifumarate derivatives of 1 which deliver the drug efficiently into the circulation of test animals, are stable in the solid state, and possess good stability in solution at low pH as required to ensure gastric stability suggests that hem ifumarate be considered as an alternative to hemisuccinate as a prodrug derivative for alcohols.
Abstract: Ether, ester, and carbonate derivatives of the antirheumatic oxindole 1 were prepared and screened as potential prodrugs of 1. This effort led to the discovery of the (alpha-L-alanyloxy)-methyl ether and hemifumarate derivatives of 1 which deliver the drug efficiently into the circulation of test animals, are stable in the solid state, and possess good stability in solution at low pH as required to ensure gastric stability. Success in achieving acceptable bioavailabilities of 1 across species (rats, dogs, and monkeys) followed the inclusion of ionizable functionality within the promoiety to compensate for masking the polar enolic OH group of the free drug. However, the introduction of ionizable functionality was often associated with decreased stability, as demonstrated by the hemisuccinate, hemiadipate, hemisuberate, and alpha-amino ester derivatives of 1 which could not be isolated. A clear exception was the hemifumarate derivative of 1 which was not only isolable but actually more stable at neutral pH than the nonionizable ester analogues. The solution and solid state stability of the hemifumarate, together with its activity as a prodrug of 1, suggests that hemifumarate be considered as an alternative to hemisuccinate as a prodrug derivative for alcohols, particularly in situations where solution state stability is an issue.
TL;DR: By using the interior metalloporphyrin functionality as a spectroscopic probe, this article showed a structure-interior property relationship for an aryl ether dendrimer family.
Abstract: By using the interior metalloporphyrin functionality as a spectroscopic probe, we have shown a structure-interior property relationship for an aryl ether dendrimer family and evaluated for the first time the interpenetrating interaction between dendrimer molecules
TL;DR: In this paper, the oxidative intramolecular phenolic coupling reaction of norbelladine derivatives was investigated with the aim of preparing amaryllidaceae alkaloids.
Abstract: The oxidative intramolecular phenolic coupling reaction of norbelladine derivatives (1) was investigated with the aim of preparing amaryllidaceae alkaloids. Spirodienone compounds (2), which are intermediates for the synthesis of an amaryllidaceae alkaloid, (+)-maritidine, or phenol ether derivatives containing the 5,6,7,8-tetrahydrobenzazocine systems (9), were selectively obtained by the reaction of 1 and the hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA). Both p−p‘ coupling (11) and p−o‘ coupling spirodienone compounds (12) were obtained by the reaction of phenol derivatives having an alkoxy group at the C-3‘ position (10) with PIFA.
TL;DR: In this article, a preliminary assessment of the properties of the polymers prepared from the catechol bis(ether anhydride) and a variety of diamines was provided, which demonstrated the possibility of synthesizing high molecular weight poly(ether imide)s with ortho-linked main-chain units from bis (ether an hydride)s derived from Catechol or its derivatives.
Abstract: Having previously demonstrated the possibility of synthesizing high molecular weight poly(ether imide)s with ortho-linked main-chain units from bis(ether anhydride)s derived from catechol or its derivatives, we now provide a preliminary assessment of the properties of the polymers prepared from the catechol bis(ether anhydride) and a variety of diamines. The polymers have low color, are soluble in a variety of solvents, and are thermally stable to temperatures in excess of 470 °C. Glass transition temperatures are comparable with or higher than that of the commercial poly(ether imide) Ultem. Solvent-cast films have high modului and strengths. Extensions to break are relatively low, except for the polymer based on 4,4‘-bis(4-aminophenoxy)biphenyl, which has an extension of 170%. All the polymers can be drawn to produce materials with higher moduli and strengths and, in most cases, higher extensions to break. Thus the polymers can be processed from the melt or from solution.
TL;DR: Galan et al. as discussed by the authors used a chiral bicyclic guanidinium salt as an anchor function for the carboxylate and a triaza-crown ether as an ammonium binding moiety in combination with a strongly hydrophobic silyl ether.
Abstract: A novel molecular host 5 for amino acid zwitterions is described. The covalent connection of a chiral bicyclic guanidinium salt as an anchor function for the carboxylate and a triaza-crown ether as an ammonium binding moiety in combination with a strongly hydrophobic silyl ether serves to complex and transfer amino acids from water into dichloromethane with unprecedented efficiency. Quantitation of the extraction process by radiometry revealed a clean 1:1 stoichiometry and gives evidence for the zwitterion as the species undergoing phase transfer. Even small hydrophilic (Ser, Gly) but no charged amino acids were extracted better by factors up to 3000-fold than by a previously reported host of similar design (Galan, A.; Andreu, D.; Echavarren, A. M.; Prados, P.; de Mendoza, J. J. Am. Chem. Soc. 1992, 114, 1511−1512). Some enantioselection in the transfer of phenylalanine was observed (40% ee).
TL;DR: The ionophores of both cyclic and noncyclic thia ethers exhibited a high selectivity for silver ion (Ag(+)), in which the sulfur atom in the ionophore molecule plays a role as the effective coordination donor site for the silver ion.
Abstract: Several 14-membered thia crown ether ionophores having a bulky block subunit were synthesized, and their chemical structures and ion selectivities were examined in detail when these compounds were used as an ion-sensing component of an ion-selective electrode. The ionophores of both cyclic and noncyclic thia ethers exhibited a high selectivity for silver ion (Ag+), in which the sulfur atom in the ionophore molecule plays a role as the effective coordination donor site for the silver ion. The best Ag+-selective electrode was prepared with the 14-membered thia crown ether having one sulfur atom, three oxygen atoms, and a bulky pinan subunit. The ion selectivity of this electrode for Ag+ was over 104 times that for other metal cations. In the case where the sulfide in the thia ether ionophore was changed to sulfoxide by oxidation, ion selectivity for mercury ion became higher; therefore, the sulfoxide was found to be an effective coordination site for the mercury ion. The ion selectivity features of noncycli...
TL;DR: In this paper, a hypervalent iodine reagent, phenyliodine(III) bis(trifluoroacetate)(PIFA), containing BF3·Et2O in CH2Cl2, was used to give the biaryl coupling products 4a-e, 5a-c and 6a−e in good yields.
TL;DR: In this paper, the reactions of 1,2-and 1,3-hydroxy azides with aldehydes under acidic conditions were examined, of which BF3·OEt2 was found the most convenient.
Abstract: The reactions of 1,2- and 1,3-hydroxy azides with aldehydes under acidic conditions were examined. A variety of Lewis acids were examined, of which BF3·OEt2 was found the most convenient. Trimethylsilyl ether derivatives of the alcohols could also be reacted using trimethylsilyl triflate as the promoter. Twenty-five examples that proceed in moderate to quantitative yields are reported.
TL;DR: Sequence-specific phenylacetylene oligomers consisting of functionalized monomers (hexyl benzoate, hexyl phenyl ether, benzonitrile, and tert-butylphenyl) are synthesized in gram quantities using solid- phase methods, producing oligomers with higher yields and simplified procedures compared to solution-phase methods.
Abstract: Sequence-specific phenylacetylene oligomers consisting of functionalized monomers (hexyl benzoate, hexyl phenyl ether, benzonitrile, and tert-butylphenyl) are synthesized in gram quantities using s...
TL;DR: Cyclocholates are efficiently and rapidly synthesised from suitable monomers by transesterification under thermodynamic, equilibrating conditions using a potassium methoxide-crown ether complex.
TL;DR: In this paper, an ab initio, quantum mechanical study of 18-crown-6 and its interaction with the alkaline earth dications Mg2+, Ca2+, Sr2+, Ba2+, and Ru2+.
Abstract: We present an ab initio, quantum mechanical study of 18-crown-6 (18c6) and its interaction with the alkaline earth dications Mg2+, Ca2+, Sr2+, Ba2+, and Ru2+. Geometries, binding energies, and binding enthalpies are evaluated at the restricted Hartree−Fock (RHF) and second-order Moller−Plesset perturbation (MP2) levels of theory using the 6-31+G* basis set and relativistic effective core potentials. The affinity of 18c6 for the dications is considerable, ranging from 150−300 kcal mol-1. The cation−18c6 interaction arises principally from the electrostatic interaction of the dication with the nucleophilic ether backbone and from the polarization of the crown ether by the electric field of the dication. Whereas Ba2+ selectivity is observed for 18c6 in aqueous environments, our calculations clearly show that the crown ether in fact binds Mg2+ most strongly in gas phase. Thus, solvation effects appear to strongly influence cation selectivity. Indeed, Ba2+ selectivity is recovered when we consider the competit...
TL;DR: Twenty-six derivatives of [SalenMn(III)](+) bearing halogen, nitro, amino, ether, alkyl, or aryl substituents on the aromatic rings and/or at the imine positions or containing 1,3-propylene', 1,2-phenylene-, 1, 2-cyclohexane-, or 1,1-diphenylethylenediamine as the bridging moiety have been synthesized.
Abstract: Twenty-six derivatives of [SalenMnIII]+ (1) bearing halogen, nitro, amino, ether, alkyl, or aryl substituents on the aromatic rings and/or at the imine positions or containing 1,3-propylene-, 1,2-p...
TL;DR: Fluorescent PET(photoinduced electron transfer) sensor 1 with monoaza-18-crown-6 ether and guanidinium receptor units shows a significant fluorescence enhancement with γ-aminobutyric acid (GABA) in mixed aqueous solution.
TL;DR: In this paper, ideal gas enthalpies of formation of butyl vinyl ether, 1,2-dimethoxyethane, methyl glycolate, bicyclo[2.2.1]hept-2-ene, trans-azobenzene, butyl acrylate, di-tert-butyl ether, and hexane-1,6-diol are reported.
Abstract: Ideal-gas enthalpies of formation of butyl vinyl ether, 1,2-dimethoxyethane, methyl glycolate, bicyclo[2.2.1]hept-2-ene, 5-vinylbicyclo[2.2.1]hept-2-ene, trans-azobenzene, butyl acrylate, di-tert-butyl ether, and hexane-1,6-diol are reported. Enthalpies of fusion were determined for bicyclo[2.2.1]hept-2-ene and trans-azobenzene. Two-phase (solid + vapor) or (liquid + vapor) heat capacities were determined from 300 K to the critical region or earlier decomposition temperature for each compound studied. Liquid-phase densities along the saturation line were measured for bicyclo[2.2.1]hept-2-ene. For butyl vinyl ether and 1,2-dimethoxyethane, critical temperatures and critical densities were determined from the dsc results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for bicyclo[2.2.1]hept-2-ene, 5-vinylbicyclo[2.2.1]hept-2-ene, trans-azobenzene, butyl acrylate, and di-tert-but...
TL;DR: In this paper, aryl cation formed by spontaneous decomposition of an aggregate-bound 4-hex is used to trap water and terminal OH groups in nonionic micelles of hexaoxyethylene monododecyl ether, C12E6.
Abstract: Chemical trapping of water and terminal OH groups in nonionic micelles of hexaoxyethylene monododecyl ether, C12E6, by an aryl cation formed by spontaneous decomposition of an aggregate-bound 4-hex...
TL;DR: In this paper, a detailed three phase nonequilibrium model for a packed catalytic distillation column is presented, which can be used for the prediction of suitable operating conditions and optimal arrangement of feed streams and packings.
TL;DR: A series of cyclic aromatic disulfide oligomers synthesized in high yields by catalytic oxidization of arenedithiols in DMAc have higher glass transition temperatures and melting points than their ether or thioether counterparts.
Abstract: A series of cyclic aromatic disulfide oligomers have been synthesized in high yields by catalytic oxidization of arenedithiols in DMAc. The aryl groups contain moieties such as ketone, sulfone, isopropylidene, ether, thioether, and phenylphosphine oxide groups. The cyclic aromatic disulfide oligomers have been analyzed by gradient HPLC, GPC, 1H-NMR, MALDI-TOF-MS, DSC, and TGA methods. Repeating units up to 9 for some cyclic aromatic disulfide ketone oligomers have been confirmed by MALDI-TOF-MS. In general, these cyclic aromatic disulfide oligomers are soluble in common organic solvents and have sharp melting points. Cyclic disulfide ketone oligomers and cyclic disulfide sulfone oligomers have higher glass transition temperatures and melting points than their ether or thioether counterparts.
TL;DR: In this paper, a series of chelated organolithium reagents (Me2O, THF, oxetane, pyridine, and imidazole chelated groups) were analyzed under slow exchange in dimethyl ether solution.
Abstract: Coordinating solvents have a profound influence on the reactivity, stereochemistry, and regiochemistry of organolithium reagents. Solvation by HMPA has been extensively documented because it is unique among monodentate coordinating solvents in that slow dynamic exchange on the NMR time scale can be achieved at moderately low temperatures (below -100 °C) in solvents such as THF and ether.1a,2 For polydentate amines the kinetics of exchange between free and coordinated ligands is also slow enough for direct NMR observation.3,4 However, the detailed nature of interactions with ethers in solution has had to be surmised indirectly because only averaged NMR spectra could be observed.5 A major advance was the recent report by Lucht and Collum that individual ether solvates of a lithium amide can be detected by NMR spectroscopy in hydrocarbon solvent.6 We report the results of an NMR study of a series of chelated organolithium reagents during which we detected for the first time individual diastereomeric ether solvates (Me2O, THF, oxetane, pyridine) under slow exchange in dimethyl ether solution, which allowed direct evaluation of the relative coordinating ability of these solvents. The organolithium reagents 1, 2, and 3 (previously used to study the effects of chelation on stereochemical inversion at the carbanion center)1b are unusual in that they form bis-HMPA contact ion pairs (CIP, 2‚(HMPA)2) identified by the triplet at 0.7 ppm in the 7Li NMR spectrum (Figure 1 shows an HMPA titration of 2). Nonchelated analogs form only trace amounts of this species and instead form separated ion pairs (SIP).1b The two HMPA groups are diastereotopic by Virtue of the asymmetric center at the lithium-bearing carbon (two 1:1:1:1 quartets at 26.8 and 27.0 ppm in the 31P NMR spectra). The reagents 1 and 3 show very similar behavior, as do analogs with amine, ether, pyridyl, and imidazole chelated groups.1c
TL;DR: Fungitoxicity assays demonstrated that the 5-methoxyluteolinidin is a phytoalexin as it prevented germination by, and killed conidia ofColletotrichum sublineolum, the sorghum anthracnose pathogen, at a concentration of 3μ M .