- A Mechanistic Study of the Reaction of OH with Dimethyl-d6 Sulfide. Direct Observation of Adduct Formation and the Kinetics of the Adduct Reaction with O2
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A pulsed laser photolysis-pulsed laser-induced fluorescence technique has been employed to study the detailed mechanism for the reaction of OH radicals with deuterated dimethyl sulfide .Equilibration of pulsed laser-generated OH with a (CD3)2S-OH adduct has been directly observed, thus confirming the existence of this controversial weakly bound species.Elementary rate coefficients for adduct formation and decomposition and, therefore, the equilibrium constant for OH + (CD3)S (CD3)2SOH have been determined as a function of temperature.From tte temperature dependence of the equilibrium constant over the relatively narrow temperature range 250-267 K, a 258 K adduct bond strength of 13.0 +/- 3.3 kcal mol-1 has been obtained (second law method).Alternatively, an entropy change calculated using standard statistical mechanical methods and ab initio theory (for determining the (CD3)2S and (CD3)2SOH structures) has been employed in conjunction with an experimental value for the equilibrium constant at a single temperature to obtain a 258 K adduct bond strength of 10.1 +/- 1.1 kcal mol-1 (third law method).Experiments in the presence of O2 confirm the previously reported dependence of the OH + DMS-d6 rate coefficient on the O2 partial pressure and are consistent with the previously proposed four-step mechanism involving hydrogen abstraction, addition of OH to the sulfur atom, and adduct decomposition in competition with an adduct + O2 reaction .The rate coefficient for the adduct + O2 reaction is found to be (8 +/-3 ) x 1E-13 cm3 molecule-1 s-1 independent of pressure (100-700 Torr of N2) and temperature (250-300 K).
- Hynes, A. J.,Stoker, R. B.,Pounds, A. J.,McKay, T.,Bradshaw, J. D.,et al.
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- Synthesis, reactivity and characterization of Pt(II) complexes with N,N′ chelating ligands; Structure and dimethylsulfoxide reactivity relationship
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Platinum(ii) complexes of the formula PtLCl2 [L = 2-(2′-pyridyl)quinoxaline, (pqx) (1), 2,(2′-pyridyl)benzo[g]quinoxaline, (pbqx) (3) and 2,(2′-pyridyl)quinoline, (pqn) (5)] were synthesized and characterized by spectroscopic and X-ray diffraction methods. Also, monodentate coordination of the ligands pqx and pbqx formed the complexes trans-Pt(DMSO)pqxCl2 (2) and trans-Pt(DMSO)pbqxCl2 (4) as it is indicated from X-ray crystal structure and NMR studies. The reaction of the complexes (1), (3) and (5) with DMSO-d6 revealed a ligand-release solvolysis, which was studied by means of NMR techniques. Correlation between the crystal structures of (1), (3), and (5) and the kinetic or thermodynamic parameters of the solvolysis reactions showed that the tendency of the ligands pqx, pbqx, and pqn to return to the anti-configuration in addition to their ability to form non-classical H-bonds are crucial factors for the ligand-release solvolysis. Instantaneous DMSO-d6 solvolysis for the complexes (1) and (3) and slow kinetics solvolysis for (5) (k = 10-4 ± 6.4 × 10-6 s-1) reflect their structural differences in ligand planarity. Based on NMR techniques a two-step mechanism of the chelate ring opening was suggested with equilibrium constants of the overall reaction at 298 K, Keq = 4.1 ± 0.2 × 10-4 M-1 (1) and Keq = 1.7 ± 0.2 × 10-4 M-1 (2).
- Ypsilantis, Konstantinos,Tsolis, Theodoros,Kourtellaris, Andreas,Manos, Manolis J.,Plakatouras, John C.,Garoufis, Achilleas
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p. 1467 - 1480
(2017/02/10)
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- ULTRAVIOLET RADIATION ABSORBING POLYETHERS
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A polymer composition comprising a linear ultraviolet radiation absorbing polyether that comprises a chemically bound UV-chromophore.
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(2014/02/15)
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- C-19 MODIFIED TRITERPENOIDS WITH HIV MATURATION INHIBITORY ACTIVITY
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Compounds having drug and bio-affecting properties, their pharmaceutical compositions and methods of use are set forth. In particular, C-19 modified triterpenoids that possess unique antiviral activity are provided as HIV maturation inhibitors, as represented by compounds of Formulas I and II: These compounds are useful for the treatment of HIV and AIDS.
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(2014/08/19)
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- POLYARYLENE POLYMERS AND PROCESSES FOR PREPARING
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Provided are sulfone-containing polyarylene polymers. Also provided are monomers and processes for preparing the polymers. The polyarylene polymers are suitable for use as engineering polymers.
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- Carbamoyl tetrahydropyridine derivatives
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Carbamoyl tetrahydropyridine derivatives represented by the formula: [in the formula, R1and R2are identical or different, and each represents a hydrogen atom, a C1-C5alkyl group, or the like; Y1-Y2represents (R4)C═C(R5), (R6)C═N, N═N, (R7)N—CO, or N═C(R8); X1, X2, and X3are identical or different, and each represents a hydrogen atom, a halogen atom, or the like; R3, R4, R5, and R6are identical or different, and each represents a hydrogen atom or an alkyl group; R7represents a hydrogen atom, a C1-C5alkyl group, or the like; and R8represents a hydrogen atom or a carbamoyl group] or a pharmaceutically acceptable salt thereof, and intermediates for the preparation thereof are provided. The derivatives described above are effective for diseases which are believed to involve CRF.
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- Methods for treatment of sickle cell anemia
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The preparation and use of a protected organic aldehyde is described wherein bioavailability of the orally administered therapeutic aldehyde is improved. The protected aldehyde is prepared by reacting the aldehyde with a protecting group, for example, condensing the aldehyde chemically with a thiazolidine-4-carboxylic acid. The improved bioavailability of such orally administered drugs increases the feasibility of delivering sufficient amounts of vanillin or other therapeutic organic aldehydes in vivo to prevent sickling in sickle cell anemia. Combination therapy is also described wherein a protected organic aldehyde is administered to a subject in treatment of sickle cell anemia in conjunction with one or more other drugs, such as pain killers, used in treatment of the symptoms of sickle cell anemia or sickle cell disease.
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- ENZYME DETECTION/ASSAY METHOD AND SUBSTRATES
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The invention relates to a method of detecting and/or assaying nucleoside hydrolases or nucleoside phosphorylases using a chromogenic substrate. Preferred chromogenic substrates have formula (I) where X is OH, or H, and Y is the residue of Y—OH where Y—OH is a chromophore or a compound readily converted to a chromophore and the substrates are hydrolysed by the nucleoside hydrolase to yield ribose or 2-deoxyribose plus Y—OH. Alternatively those substrates may be phosphorylysed by nucleoside phosphorylase to yield ribose-1-phosphate plus Y—OH. The methods may be used to detect and/or assay parasites in biological samples.
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- Bicyclic amino derivatives and PGD2 antagonist containing the same
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A compound of the formula (I): wherein for example, a compound below: whereinR1 is CH3, H or Na; and X1-X2-X3 is or its salt or a hydrate thereof is useful as PGD2 antagonist and can be used as a drug for treating diseases in which mast cell dysfunction is involved, for example, systemic mastocytosis and disorder of systemic mast cell activation, and also tracheal contraction, asthma, allergic rhinitis, allergic conjunctivitis, urticaria, injury due to ischemic reperfusion, and as an anti-inflammatory agent. It is particularly useful in the treatment of nasal occlusion.
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- Nitrogen containing heteroaromatics as factor Xa inhibitors
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The present application describes nitrogen containing heteroaromatics and derivatives thereof of formula I: or pharmaceutically acceptable salt or prodrug forms thereof, wherein J is N or NH and D may be C(=NH)NH2, which are useful as inhibitors of factor Xa.
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- Organic electroluminescence device, organic thin film, and triamine compound
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PCT No. PCT/JP96/00082 Sec. 371 Date Jul. 21, 1997 Sec. 102(e) Date Jul. 21, 1997 PCT Filed Jan. 19, 1996 PCT Pub. No. WO96/22273 PCT Pub. Date Jul. 25, 1996The present invention provides a triamine compound represented by general formula (I): an organic luminescence device which comprises an organic layer and a pair of electrodes disposed on both sides of the organic layer wherein the organic layer at least contains a layer of a light emitting zone and a layer of a hole transporting zone which comprises a hole injecting layer containing the triamine compound and a hole transporting layer, and an organic thin film comprising two layers which are a layer containing a compound represented by general formula (I) and having a thickness of 5 nm to 5 mu m and a layer containing a compound represented by general formula (II):
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- Process for making 5-substituted pyrazoles
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This invention relates to a novel process of preparing selected 5-substituted pyrazoles useful as p38 kinase and COX-2 inhibitors.
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- Mechanism of sulfone formation in the reaction of sulfides and singlet oxygen: Intermediacy of S-hydroperoxysulfonium ylide
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H-D exchange was observed in the methyl group during the formation of sulfones in the reaction of dimethyl sulfide-d6 or thioanisole-α,α,α-d3 with singlet oxygen in aprotic solvents. No exchange was observed in the sulfoxides obtained. The proton in the sulfones was shown to come from adventitious water, since the oxidation of C6H5SCH3 in the presence of D2O lead to the formation of sulfones with monodeuteriation. The 16O2-18O2 tracer study demonstrated no oxygen scrambling in the sulfones. All the results indicate that the sulfones are formed intramolecularly via an intermediate possessing one activated proton exchangeable with trace water, a suggested structure for which is S-hydroperoxysulfonium ylides (RS+(OOH)CH2-). Kinetic isotope effects (k(H)/k(D) = 2-4) observed for methyl protons in the sulfone formation suggest that the rate-determining step is the intramolecular proton abstraction in the persulfoxides (RS+(OO-)CH3) generating S-hydroperoxysulfonium ylides. The conversion of the ylide intermediates to sulfones is shown to be facile on the basis of PM3 theoretical calculations.
- Ishiguro, Katsuya,Hayashi, Masaki,Sawaki, Yasuhiko
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p. 7265 - 7271
(2007/10/03)
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- TETRAZOLEACETIC ACID DERIVATIVES HAVING ALDOSE REDUCTASE INHIBITORY ACTIVITY
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A tetrazoleacetic acid derivative represented by the following general formula (I): [in Formula (I), R1 represents a hydrogen atom or a lower alkyl group; R2, R3 and R4 are the same or different from each other and are selected from the group consisting of hydrogen, lower alkyl, halogen, lower haloalkyl, hydroxy and lower alkoxy; and tetrazol group is substituted at 1- or 2-position of naphthyl group] except for [5-(1-naphthyl)tetrazol-1-yl]acetic acid and ethyl ester thereof, or a salt thereof.
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- ANTIHERPETIC AGENTS
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A series of carboxyl-containing N-alkyldipeptides have been found to posess antiviral potency-specifically against herpes simplex virus-by selectively inhibiting the viral ribonucleotide reductase enzyme
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- TETRAZOLE DERIVATIVES AND ALDOSE REDUCTASE INHIBITION THEREWITH
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The present invention relates to an aldose reductase inhibitor having the following formula: R1 is a hydrogen atom or --A--COOR5 (A is an alkylene group having 1 to 4 carbon atoms and R5 is a hydrogen atom or a lower alkyl group), and R2, R3 and R4 are the same as or different from each other and selected from the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, a carboxyl group, an alkyl group, an amide group, an amino group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an alkylsulfinyl group, an alkylsulfonyl group, a nitro group, --NHCOCOOR6 (R6 is a hydrogen atom or a lower alkyl group), a mono or dialkylaminosulfonyl group, and a residual group having the following formula: (A and R5 are the same as in the above). The compounds defined in the above are excellent in aldose reductase inhibitory activity and low in toxicity. Therefore, those compounds are useful as a preventive agent and/or a remedy for diabetic complications such as neuropathy, retinopathy, nephropathy, cataracts and keratopathy
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- 2'-deoxy-5-fluorouridine derivatives
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Disclosed is a 2'-deoxy-5-fluorouridine derivative of the formula STR1 wherein one of R1 and R2 is a benzyl group which may optionally have substituent selected from the group consisting of C1 -C6 alkyl group, C1 -C6 alkoxy group, C1 -C3 halogenated alkyl group, halogen atom, hydroxyl group and nitro group on the phenyl ring, and the other constitutes an amino acid residue, or a salt thereof. The compounds are useful for treating cancer.
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- Proton transfers among oxygen and nitrogen acids and bases in DMSO solution
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Rate constants for the proton-transfer reactions between conjugate acids and bases of several amines, phenols, carboxylic acids, and the solvated proton in DMSO-d6 at 20 °C have been determined by the use of NMR line-shape analysis. Equilibrium constants for the same reactions are obtained from the pKa's of the acids in dimethyl sulfoxide, some of which have been reported in earlier work and the rest obtained in the present work by use of Bordwell's indicator techniques. All of the reactions have rale constants considerably below expected diffusion-controlled limits for the proton transfers in the thermodynamically favorable direction, and several of the reactions, including the identity reactions of carboxylic acids, have kinetic deuterium isotope effects, kH/kD, between 0.8 and 1.3. For reactions of N,N-dimethylbenzylammonium ion with several phenoxides, carboxylates, and solvent, the rate constants for transfers in the unfavorable directions show a reasonable Bronsted correlation with β ≈ 1 and a reasonably constant reverse rate constant of ≈3 × 106 M-1 s-1. The data clearly indicate that the proton-transfer step is not rate-limiting in these reactions. Most likely, desolvation is involved in the rate-limiting steps, but the rate constants are not simple functions of acidities as might have been expected if hydrogen bonding of acid to solvent were the major factor involved in the solvation Other factors, particularly dispersion interactions of solvent with solutes, are discussed. We suggest that the formation of an acid-base complex with proper orientation to allow contact between the proton and the basic site is rate-determining and involves desolvation along with detailed steric interactions of the acid-base pair.
- Ritchie, Calvin D.,Lu, Shanzheng
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p. 7748 - 7756
(2007/10/02)
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- Tricyclic aromatic compounds
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The present invention relates to compounds of formula I STR1 or a salt, ester or amide thereof; wherein R1 is --CH2 --CH2 --, CH2 --O-- or --O--CH2 --; R2 and R3 are the same or different and are each hydrogen, C1-4 alkyl or taken together with the nitrogen comprise a nitrogen-containing heterocyclic ring having four to six ring members; R4 is a single bond or a C1-7 bivalent aliphatic hydrocarbon group and may be joined to the aromatic ring system at the 2,3,8 or 9 positions; n is 0 to 3, and their use as anithistamine and antiasthma agents.
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- 6-Alkylidene 10 β-alkynylestrene derivatives and pharmaceutical methods for their use
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The invention relates to 6-substituted 10β-alkynylestrene derivatives wherein the 6 substituent is amino, azido, halogen or an alkylidene group and to corresponding 6,7-dihalo analogs. The invention provides also a process for the preparation of the above compounds and pharmaceutical compositions containing same. The compounds of the invention are useful aromatase inhibitors and can be used, e.g., in the treatment of hormone-dependent tumors and prostatic hyperplasia.
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- N-Imidazolyl derivatives of 1,2,3,4-tetrahydro-naphthalene and indan
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Compounds of the formula STR1 where Z completes a bond or is a STR2 group; one of R1 and R2 is hydroxy and the other is hydrogen or alkyl, or R1 and R2, taken together, form an oxo group; and the remaining substituents are as defined in the specification. These compounds possess hypolipaemic properties.
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