- Influence of substructures on the spreading ability and hydrolysis resistance of double-tail trisiloxane surfactants
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Four types of novel double-tail trisiloxane surfactants of the general formula Me3SiOSiMeR1 OSiMe3 (R1 = -(CH2)3NR2 CH2CH(OH)CH 2(OCH2CH2)xOCH3; R 2 = -CH2CH(OH)CH2OCH2 (CH 2)yCH3, -CH2 (CH2) 3CH3, -CH2CH2CH(CH3) 2; x = 8.4, 12.9, 17.5, 22; y = 2, 6), have been synthesized. Their structures were characterized by proton and carbon nuclear magnetic resonance. Most of them are able to reduce the surface tension of water to less than 24 mN/m at concentration levels of 10-5 mol/L and 10-4 mol/L. The emphasis was on the influence of substructures on their spreading ability and hydrolysis resistance. The results showed that a weaker hydrophilicity of a surfactant molecule, a larger molar ratio of methyl to methylene in the whole hydrophobic groups, more flexible hydrophobic groups and introduction of a methyl group in the spacer can all improve the spreading ability of the double-tail trisiloxane surfactant solutions on low-energy solid surfaces. The double-tail trisiloxane surfactants 1F and 2F are stable for more than 270 days in a neutral environment (pH 7.0). The hydrolysis resistance of the double-tail trisiloxane surfactants can be improved by a weaker hydrophilicity of the surfactant molecule, and a larger volume of the hydrophobic groups. Copyright
- Peng, Zhongli,Lu, Caifeng,Xu, Minling
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- Heterocyclic substituted 2-methyl-benzimidazole antiviral agents
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The present invention concerns antiviral compounds, their methods of preparation and their compositions, and use in the treatment of viral infections. More particularly, the invention provides heterocyclic substituted 2-methylbenzimidazole derivatives for the treatment of respiratory syncytial virus infection.
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- Esterification of carboxylic acid salts
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Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
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- Hydroxamic acids and esters
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The synthesis of amido substituted naphthalenes and their intermediates is described. The intermediates and amido substituted naphthalenes are useful as anti-inflammatory agents.
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- Silylaminyl Radicals. Part 2. Free Radical Chain Halogenation of Hydrocarbons using N-Halogenobis(trialkylsilyl)amines
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The liquid-phase halogenation of a number of hydrocarbons and of 1-chlorobutane by N-halogenobis(trialkylsilyl)amines has been studied using product analysis techniques.The reactions take place by free radical chain mechanisms which involve the propagation steps generalised in equations (A) and (B) (X=Br or Cl).At 353 K, the molar reactivities of toluene (benzylic C-H) and cyclohexane towards (R3Si)2N+RH(R3Si)2NH+R (A) R+(R3Si)2NXRX+(R3Si)2N (B) (Me3Si)2N are approximately equal and toluene is 5.2 times more reactive than perdeuteriotoluene.The relative rates of hydrogen abstraction by (Me3Si)2N and (ButMe2Si)2N from the primary, secondary, and tertiary C-H groups in 2-methylbutane show that the silylaminyl radicals are not only highly reactive but also sterically demanding.Thus, at 333 K the average primary C-H reactivity is 0.6 times that of the tertiary C-H towards attack by (Me3Si)2N, but 4.2 times that of the tertiary C-H towards attack by the more bulky (ButMe2Si)2N.Silylaminyl radicals are much more reactive in hydrogen abstraction than are analogous dialkylaminyl radicals and this difference is interpreted in terms of thermodynamic and polar effects which arise because of the ?-donor-?-acceptor nature of the trialkylsilyl substituent.
- Cook, Malcolm D.,Roberts, Brian P.,Singh, Karamjit
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p. 635 - 644
(2007/10/02)
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- 3,11-Dihydro- 6H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]pyrido[4,3-d]pyrimidin-6-one and derivatives thereof
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New 3,11-dihydro-6H-pyrazolo[1,5-a]pyrazolo[4',3':5,6]-pyrido[4,3-d]pyrimidin-6-one and new derivatives thereof have the general formula STR1 The compounds are useful as anti-inflammatory agents.
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