1124-32-9Relevant academic research and scientific papers
Di- tert -butylisobutylsilyl, another useful protecting group
Liang, Huan,Hu, Lin,Corey
scheme or table, p. 4120 - 4123 (2011/10/04)
The di-tert-butylisobutylsilyl (BIBS) protecting group offers new possibilities for synthetic processes because of its steric bulk, robustness of its derivatives, and other special properties.
NOVEL 2'-C-METHYL AND 4'-C-METHYL NUCLEOSIDE DERIVATIVES
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Page/Page column 126, (2008/06/13)
Novel 2'-C-methyl nucleoside 5 '-monophosphate and 4'-C-methyl nucleoside 5'- monophosphate derivatives, stereoisomers, and pharmaceutically acceptable salts or prodrugs thereof, their preparation, and their uses for the treatment of hepatitis C viral inf
Significant and differential acceleration of dephosphorylation of the insecticides, paraoxon and parathion, caused by alkali metal ethoxides.
Um, Ik-Hwan,Jeon, Sang-Eun,Baek, Mi-Hwa,Park, Hye-Ran
, p. 3016 - 3017 (2007/10/03)
In the reaction of paraoxon with alkali metal ethoxides, ion-paired EtO-M+ species are more reactive than the dissociated EtO- with the reactivity order EtO-Li+ EtO-Na+ > EtO-K+ > EtO-, while in the reaction of parathion, the reactivity follows the order
Alkali metal ion catalysis in nucleophilic displacement by ethoxide ion on p-nitrophenyl phenylphosphonate: Evidence for multiple metal ion catalysis1
Buncel, Erwin,Nagelkerke, Ruby,Thatcher, Gregory R.J.
, p. 53 - 63 (2007/10/03)
In continuation of our studies of alkali metal ion catalysis and inhibition at carbon, phosphorus, and sulfur centers, the role of alkali metal ions in nucleophilic displacement reactions of p-nitrophenyl phenylphosphonate (PNPP) has been examined. All al
Proton affinities and aggregation states of lithium alkoxides, phenolates, enolates, β-dicarbonyl enolates, carboxylates, and amidates in tetrahydrofuran
Arnett, Edward M.,Moe, Kevin D.
, p. 7288 - 7293 (2007/10/02)
The proton affinities of the title compounds are represented by their heats of deprotonation, ΔHdep, through reactions with lithium bis(trimethylsilyl)amide, LiHMDS, in tetrahydrofuran at 25°C. Aggregation numbers of the parent acid and of its lithium salt at a concentration of 0.10 M were obtained by vapor-pressure osmometry at 37°C. Lithium phenolates were also studied by conductivity at 25°C. ΔHdeps for 27 oxygen, nitrogen, and carbon acids of varied types correlate fairly well (R = 0.95) with their published pKas in dimethyl sulfoxide although their degrees of aggregation in THF vary from one to over seven. In some cases, the ΔHdep of an acid is strongly dependent on the concentration ratio of LiHMDS to that of the acid's lithium salt at the time of measurement. Aggregation numbers determined by VPO in this report agree with available published values obtained by previous workers using several techniques. There is no obvious relationship between the aggregation number of the lithium salt and the basicity of the corresponding anion as represented by ΔHdep. This observation along with independent evidence for equilibria between monomers, dimers, tetramers, etc. for a number of compounds indicate that there are only small differences between the relative stabilities of different aggregation states. Conductance data for lithium p-nitrophenolate were treated by Wooster analysis, the results of which suggest equilibria between ion triplets, ion pairs, and free ions in THF. The conductance of LiHMDS in this solvent is surprisingly high, and this property was used to demonstrate an interaction between LiHMDS and lithium o-tert-butylphenolate.
HYDROLYSE BASIQUE COMPAREE D'ESTERS ALLOPHANIQUES ET PHOSPHORIQUES EN MILIEU MIXTE ACETONITRILE/EAU FAIBLEMENT AQUEUX; MISE EN EVIDENCE D'UNE ENTITE CATALIQUE, INTERMEDIARE DE LA REACTION ENTRE BASE ET SOLVANT
Monnier, Par E.,Botella, J. M.,Murillo, A.,Klaebe, A.,Perie, J.
, p. 1315 - 1332 (2007/10/02)
Kinetic study of base catalysed hydrolysis in acetonitrile-water mixtures of allophanic esters (models of carboxybiotine) and phosphoric esters shows in the range of low water content (less than 1 molar) an enhancement in rate (103) with a maximum at 0.1-0.3 molar in water.This rate enhancement is ascribed to ground state desolvation and the maximum is interpreted by a change in the rate determining step: leaving group departure in the tetrahedral intermediate is indeed the slow step for the reactions in acetonitrile/water mixture less than 0.1 molar in water.For charged phosphoric esters the rate enhancement from an aqueous medium (pH=10) to organic is larger since as high as 106.On the other hand, in such a medium, an additional catalytic effect is observed; it is shown that it is due to the formation of a reactive species which results from reaction of the base on acetamide when accumulated in the medium from base catalysed hydrolysis of the solvent.
