Showing papers in "Canadian Journal of Chemistry in 1989"
TL;DR: The causative agent of toxicity in cultured mussels from a localized area of eastern Prince Edward Island has been identified as domoic acid, a neuroexcitatory amino acid.
Abstract: The causative agent of toxicity in cultured mussels from a localized area of eastern Prince Edward Island has been identified as domoic acid, a neuroexcitatory amino acid The toxin was isolated by
420 citations
TL;DR: In this article, nuclear magnetic resonance spectroscopic evidence is presented in characterizing three new structurally modified forms of heparin, polymer M-I, which represents a conversion of about two-th...
Abstract: Nuclear magnetic resonance spectroscopic evidence is presented in characterizing three new structurally modified forms of heparin. One of these, polymer M-I, represents a conversion of about two-th...
142 citations
TL;DR: In this article, a pulsed electron high pressure mass spectrometer (PHPMS) was used to measure the gas phase proton transfer equilibrium, and the relative acidities were converged.
Abstract: Measurements of the gas phase proton transfer equilibrium [1]: AH + B− = A− + BH with a pulsed electron high pressure mass spectrometer (PHPMS) lead to and data. These relative acidities are conver...
133 citations
TL;DR: A series of 30 phenyl substituted derivatives of 2-phenyl-1,1,3,3-tetramethylguanidine was synthesized and the pKa value of each was measured in acetonitrile using a conventional, general purpose g...
Abstract: A series of 30 phenyl substituted derivatives of 2-phenyl-1,1,3,3-tetramethylguanidine was synthesized and the pKa value of each was measured in acetonitrile using a conventional, general purpose g...
93 citations
TL;DR: Apparent molar adiabatic compressibilities and volumes of aqueous solutions of the following drugs (sodium salicylate, methyl orange, L-tryptophan, phenol, and the hydrochloride salts of propranalo...
Abstract: Apparent molar adiabatic compressibilities and volumes of aqueous solutions of the following drugs (sodium salicylate, methyl orange, L-tryptophan, phenol, and the hydrochloride salts of propranalo...
91 citations
TL;DR: Under the appropriate reaction conditions, sodium borohydride is a highly chemoselective reducing agent as mentioned in this paper, and the order of reactivity among carbonyl groups is conjugated enones,
Abstract: Under the appropriate reaction conditions, sodium borohydride is a highly chemoselective reducing agent. The order of reactivity among carbonyl groups is conjugated enones < ketones < conjugated al...
75 citations
TL;DR: In this article, the effect of macrocyclic crown ether and cryptand complexing agents on the rate of the nucleophilic displacement reaction of p-nitrophenyl diphenylphosphinate by alkali metal ethoxides in ethanol at 25 °C has been studied by spectrophotometric techniques.
Abstract: The effect of macrocyclic crown ether and cryptand complexing agents on the rate of the nucleophilic displacement reaction of p-nitrophenyl diphenylphosphinate by alkali metal ethoxides in ethanol at 25 °C has been studied by spectrophotometric techniques. For the reactions of potassium ethoxide, sodium ethoxide, and lithium ethoxide, the observed rate constant increased in the order KOEt < NaOEt < LiOEt. Crown ether and cryptand cation-complexing agents have a retarding effect on the rate. Increasing the ratio of complexing agent to base results in a decrease in kobs to a minimum value corresponding to the rate of reaction of free ethoxide ion. In complementary experiments, alkali metal ions were added to these reaction systems in the form of unreactive salts, causing an increase in reaction rate. The kinetic data were analysed in terms of ion-pairing treatments, which allowed evaluation of rate coefficients due to free ethoxide ions and metal ion – ethoxide ion pairs. Possible roles of the metal cations...
72 citations
TL;DR: In this paper, the oxidation kinetics of GSH by hydrogen peroxide were studied at neutral pH for different concentration ratios [GSH]0/[H2O2]0 between 0.2 and 2.
Abstract: The oxidation kinetics of glutathione (GSH) by hydrogen peroxide has been studied at neutral pH for different concentration ratios [GSH]0/[H2O2]0 between 0.2 and 2 (5 × 10−4 M ≤ [H2O2]0 ≤ 2.5 × 10−...
69 citations
TL;DR: The alkaloids of the club moss Lycopodiumobscurum L, collected in Northern Alberta, have been investigated in this paper, and the known alkaloid species include lycopodine, lycodine, clavolonine, dihydrolycopodines, O-acetyldehydr...
Abstract: The alkaloids of the club moss Lycopodiumobscurum L., collected in Northern Alberta, have been investigated. The known alkaloids lycopodine, lycodine, clavolonine, dihydrolycopodine, O-acetyldehydr...
64 citations
TL;DR: The electrochemical oxidation of glycine at a Pt electrode was investigated in aqueous solutions at pH 1 and 13 using steady-state currentpotential measurements, cyclic voltammetry, and open circu...
Abstract: The electrochemical oxidation of glycine at a Pt electrode was investigated in aqueous solutions at pH 1 and 13 using steady-state current–potential measurements, cyclic voltammetry, and open circu...
57 citations
TL;DR: In this paper, the synthesis and magnetic data of four copper(II) complexes obtained from squaric acid and bipyridyl or imidazole as ligand are described.
Abstract: The synthesis and magnetic data of four copper(II) complexes obtained from squaric acid and bipyridyl or imidazole as ligand are described. Cu(C4O4)(imidazole)2•2H2O (compound I) is made of chains ...
TL;DR: Selagine, an alkaloids of Lycopodiumselago, is shown to be identical with huperzine A, and a minor alkaloid, C15H18N2O2, isolated from L. selago is found to be 6β-hydroxyhuperZine A.
Abstract: Selagine, an alkaloid of Lycopodiumselago, is shown to be identical with huperzine A (2). A minor alkaloid, C15H18N2O2, isolated from L. selago is found to be 6β-hydroxyhuperzine A (4). Keywords: huperzine A, selagine, Lycopodium alkaloids, Alzheimer's disease, acetylcholine esterase inhibitor.
TL;DR: In this article, the highly reproducible pH-stat technique was used to study the influence of various types of inhibitors on the precipitation of calcium phosphate from solution, and three types of inhibitor types were evaluated.
Abstract: The highly reproducible pH-stat technique was used to study the influence of various types of inhibitors on the precipitation of calcium phosphate from solution. Three types of inhibitors were eval...
TL;DR: The secondary metabolites of the sponge Hexadella sp., collected by SCUBA (−40 m) and manned submersible (−100 to −200 m) in Jervis Inlet, British Columbia, have been examined as mentioned in this paper.
Abstract: The secondary metabolites of the sponge Hexadella sp., collected by SCUBA (−40 m) and manned submersible (−100 to −200 m) in Jervis Inlet, British Columbia, have been examined. The submersible-coll...
TL;DR: In this article, a method for the synthesis of polybis(μ-pyrazolato-N,N′)copper(II), [Cu(pz)2]x(where pz =N2C3H3), is presented.
Abstract: A novel and reliable method for the synthesis of polybis(μ-pyrazolato-N,N′)copper(II), [Cu(pz)2]x(where pz = N2C3H3), is presented. Single crystals of the polymer suitable for X-ray study have been...
TL;DR: The dielectric constants, viscosities, densities, and refractive indices of binary solvent mixtures of dimethylsulfoxide-isopropanol and propylene carbonate-isophosphoric acid were measured at 25, 30, and 30, respectively, in this paper.
Abstract: The dielectric constants, viscosities, densities, and refractive indices of the binary solvent mixtures dimethylsulfoxide–isopropanol and propylene carbonate–isopropanol were measured at 25, 30, an...
TL;DR: Excess partial molar enthalpies of 2-butoxyethanol (BE) and water, (I = BE or H2O), were measured from 25 to 35 °C in the entire concentration range.
Abstract: Excess partial molar enthalpies of 2-butoxyethanol (BE) and water, (I = BE or H2O), were measured from 25 to 35 °C in the entire concentration range. The results indicated that there are three conc...
TL;DR: In this article, the rate constants for hydrogen abstraction from benzene, toluene, and cyclopentane by methyl and ethyl radicals have been measured relative to the corresponding abstraction reaction from ethyle...
Abstract: Rate constants for the abstraction of hydrogen from benzene, toluene, and cyclopentane by methyl and ethyl radicals have been measured relative to the corresponding abstraction reaction from ethyle...
TL;DR: Two of the less prominent members with P388 ED50 10−3–10−2 μg/mL, cephalostatins 5 and 6, were isolated and assigned structures based on rigorous interpretation of two-dimensional 400-MHz 1H and 13C nuclear magnetic resonance.
Abstract: The Indian Ocean (South African) marine worm Cephalodiscusgilchristi (Hemichordata phylum) has been found to contain a series of unusual disteroidal alkaloids, designated the cephalostatins, that possess exceptionally potent lymphocytic leukemia (murine P388) cell line inhibitory activity (to ED50 10−9 μg/mL). Two of the less prominent members with P388 ED50 10−3–10−2 μg/mL, cephalostatins 5 (2) and 6 (3), were isolated and assigned structures based on rigorous interpretation of two-dimensional 400-MHz 1H and 13C nuclear magnetic resonance. Keywords: cephalostatins 5 and 6, disteroidal alkaloids, lymphocytic leukemia, cytostatic, Cephalodiscusgilchristi.
TL;DR: New quinoline alkaloids were obtained from Galipeallongiflora Krause (Rutaceae) as mentioned in this paper, including 2-phenylquinoline, 2-namyl-4-methoxyquinoline and 2-phenyl-1.
Abstract: Five new 2-aryl and 2-alkyl quinoline alkaloids were obtained from Galipeallongiflora Krause (Rutaceae). These are 2-phenylquinoline 1, 2-(3′,4′-methylenedioxyphenethyl)quinoline 2, 2-(3′,4′-dimethoxyphenethyl)quinoline 3, 2-(3′,4′-methylenedioxystyryl)-4-methoxyquinoline 4, and 2-(1′,2′-pentenyl)-4-methoxyquinoline 6. They are accompanied by three known 2-substituted quinolines, 2-n-amyl-4-methoxyquinoline 5, 2-(3′4′-methylenedioxyphenethyl)-4-methoxyquinoline 7, and 2-phenyl-4-methoxyquinoline 8, and by two known furo[2,3b]quinoline alkaloids: evolitrine and skimmianine. Keywords: Galipealongiflora, Rutaceae, new quinolines.
TL;DR: The reaction of tetrabutylammonium tribromide (TBABr3) with phenols and aromatic amines in aprotic and non-basic solvents at 20 °C gives exclusively the corresponding para-brominated compounds in h...
Abstract: The reaction of tetrabutylammonium tribromide (TBABr3) with phenols and aromatic amines in aprotic and non-basic solvents at 20 °C gives exclusively the corresponding para-brominated compounds in h...
TL;DR: In this paper, a 1:2 mole ratio was obtained from methanol solutions containing Cu(CF3SO3)2 and pyrazine in approximate 1:4 diazine ratio.
Abstract: Orange–brown crystals of composition Cu(pyz)2(CF3SO3) (pyz = pyrazine, 1,4-diazine) were obtained from methanol solutions containing Cu(CF3SO3)2 and pyrazine in approximate 1:2 mole ratio. Single c...
TL;DR: In this article, the transformation of the readily available keto acetal 14 into the enone 23 was accomplished via a seven-step sequence of reactions, using the bifunctional Grignard reagent.
Abstract: Transformation of the readily available keto acetal 14 into the enone 23 was accomplished via a seven-step sequence of reactions. Reaction of 23 with the bifunctional Grignard reagent 5 in the pres...
TL;DR: The fungus Marasmiusoreades has been reported to produce the sesquiterpenes marasmone (1), anhydromarasmone(2), isomarasmones (3), and dihydromarsmone (4) when grown in liquid culture.
Abstract: The fungus Marasmiusoreades has previously been reported to produce the sesquiterpenes marasmone (1), anhydromarasmone (2), isomarasmone (3), and dihydromarasmone (4) when grown in liquid culture. ...
TL;DR: In this paper, pre-micellar and micellar sodium perfluorooctanoate (SPFO) solutions were examined conductometrically with added α-cyclodextrin(α-CD), β-cyclodesxtrin (β-CD) and γ-cyclodextrin (γ-CD).
Abstract: Pre-micellar and micellar sodium perfluorooctanoate solutions (SPFO) were examined conductometrically with added α-cyclodextrin(α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD). The order of...
TL;DR: The coordinatively unsaturated binuclear rhodium hydrides react rapidly with dihydrogen to yield the fluxional binuclear tetrahydrides [Pri2P(CH2nPPri2}Rh]2(μ-H)2 (n = 2: 1b; n ǫ=n 3: 1c; n ë = n 4 : 1d).
Abstract: The coordinatively unsaturated binuclear rhodium hydrides [{Pri2P(CH2)nPPri2}Rh]2(μ-H)2 (n = 2: 1b; n = 3: 1c; n = 4: 1d) react rapidly with dihydrogen to yield the fluxional binuclear tetrahydrides [{Pri2P(CH2)nPPri2}RhH]((μ-H)3[Rh{Pri2P(CH2)nPPri2}] 2b–d(n = 2–4). The dihydride 1b was structurally characterized by single crystal X-ray diffraction. While the tetrahydrides 2b and 2c were found to be stable only in solution in the presence of excess dihydrogen, 2d was stable in the solid state. Three separate exchange processes were characterized for 2b–d via 1H and 31P{1H} NMR spectroscopy: intermolecular exchange with free dihydrogen, and two intramolecular processes exchanging the four hydride ligands. The geometry about the rhodium centres in the limiting structures involved in these processes is affected by the chelate ring size of the ancillary diphosphine ligand. A "rocking" process observed at low temperatures for each of these tetrahydrides has a ΔG≠ of <7.0(5) kcal/mol, 8.6(5) kcal/mol, and 11.5(...
TL;DR: In this paper, the potential of tetraneopentoxyphthalocyaninatocobalt(II) species adsorbed on glassy carbon (GC), ordinary pyrolytic graphite (OPG), and highly oriented pyrolysic graphite(HOPG) was analyzed under both argon and dioxygen.
Abstract: Potentiodynamic data were obtained under argon for the mononuclear species tetraneopentoxyphthalocyaninatocobalt(II) species adsorbed on glassy carbon (GC), ordinary pyrolytic graphite (OPG), and highly oriented pyrolytic graphite (HOPG). Comparative data show that the most convenient material to use is HOPG whereon a limiting monolayer is apparently achieved. Data were also presented for the mononuclear and polynuclear analogues on HOPG under both argon and dioxygen. Comparison is made of the potential data obtained in water and in organic solvent. A pH dependence study shows that the dioxygen reduction potential tracks the Co(II)TNPc/Co(I)TNPc redox couple with a slope of approximately −65 mV/pH for the mononuclear species, in the acid regime, but substantially less than −65 mV/pH for the polynuclear species. There is no pH dependence in the alkaline regime. Possible mechanisms are discussed. Keywords: phthalocyanine, electrochemistry, dioxygen reduction, pH dependence, graphite electrode, cobalt phthal...
TL;DR: The procedure for its analysis which is commonly employed in North America is a NIOSH recommended one t... as discussed by the authors, which is the most commonly used one in the world for formaldehyde analysis.
Abstract: Formaldehyde is present in the indoor air of many industrial and non-industrial environments. The procedure for its analysis which is commonly employed in North America is a NIOSH recommended one t...
TL;DR: In this article, the torsion angle about the bond in anisole was optimized with the basis set 6-31G for seven values of θ, and all bond angles and lengths were optimized.
Abstract: Molecular orbital computations with the basis set 6-31G are reported for seven values of θ, the torsion angle about the bond in anisole. All bond angles and lengths are optimized but the atoms of t...