4374-62-3Relevant academic research and scientific papers
A study of the reaction of n-BuLi with Ti(Oi-Pr)4 as a method to generate titanacyclopropane and titanacyclopropene species
Rassadin, Valentin A.,Six, Yvan
, p. 787 - 794 (2014/01/23)
The use of the combination of reagents Ti(Oi-Pr)4/n-BuLi, introduced by the group of J.J. Eisch in 2001, has only found a few applications so far, with sometimes conflicting observations. This article describes a study aimed at clarifying the nature, the stability and the reactivity of the active organometallic species involved. Reactions with CO2 and other trapping reagents reveal that it is generated within a few minutes at 0 C in THF, where it can be considered to be stable for 30 min. Most of our results are consistent with the expected titanacyclopropane nature of this reagent but some observations suggest that the chemistry at play may be more complicated.
Mechanistic investigation of the selective reduction of Meldrum's acids to β-hydroxy acids using SmI2 and H2O
Szostak, Michal,Lyons, Sarah E.,Spain, Malcolm,Procter, David J.
supporting information, p. 8391 - 8394 (2014/07/22)
The mechanism of a recently reported first mono-reduction of cyclic 1,3-diesters (Meldrum's acids) to β-hydroxy acids with SmI 2-H2O has been studied using a combination of reactivity, deuteration, kinetic isotope and radical clock e
Selective reductions of cyclic 1,3-diesters by using SmI2 and H2O
Collins, Karl D.,Oliveira, Juliana M.,Guazzelli, Giuditta,Sautier, Brice,De Grazia, Sara,Matsubara, Hiroshi,Helliwell, Madeleine,Procter, David J.
scheme or table, p. 10240 - 10249 (2010/11/18)
SmI2/H2O reduces cyclic 1,3-diesters to 3-hydroxyacids with no over reduction. Furthermore, the reagent system is selective for cyclic 1,3-diesters over acyclic 1,3-diesters, and esters. Radicals formed by one-electron reduction of the ester carbonyl group have been exploited in intramolecular additions to alkenes. The ketal unit and the reaction temperature have a marked impact on the diastereoselectivity of the cyclizations. Cyclization cascades are possible when two alkenes are present in the starting cyclic diester and lead to the formation of two rings and four stereocenters with excellent stereocontrol.
Highly regioselective intramolecular hydroxymethylation of α,β-unsaturated carboxylic acids
Linker, Torsten,Maurer, Michael,Rebien, Frank
, p. 8363 - 8366 (2007/10/03)
A convenient synthesis of hydroxy esters 7 and lactones 8 by starting from easily available α,β-unsaturated carbocylic acids 4 is described. The key step of this transformation is a hitherto unknown radical cyclization of silyl esters, which exhibits a high degree of regioselectivity through steric and orbital control.
Process for preparation of an optically active β-mercaptoalkanoic acid
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, (2008/06/13)
A process is disclosed wherein an optically active β-mercaptoalkanoic acid represented by formula (I): STR1 wherein R1 is lower alkyl having from 1 to 4 carbon atoms, is prepared by (1) reacting an optically active β-hydroxyalkanoic acid represented by formula (II): STR2 wherein R1 is the same as defined above, with a halogenating reagent to prepare an optically active β-haloalkanoyl halide represented by formula (III): STR3 wherein X is halogen and R1 is the same as defined above; (2) reacting the β-haloalkanoyl halide with water or an aqueous alkaline solution to prepare an optically active β-haloalkanoic acid represented by formula (IV): STR4 wherein X and R1 are each the same as defined above, or a salt thereof, respectively; and (3) reacting the β-haloalkanoic acid or the salt thereof with a reagent capable of converting the halogen into the thiol group, the configuration of the compound (II), (III), and (IV) being retained throughout the process to prepare the compound represented by formula (I). The product of the present invention is useful as an intermediate for preparation of an antihypertensive agent such as N-(3-mercapto-2-D-methylpropanoyl)-L-proline.
Enantiotopically Selective Oxidation of α,ω-Diols with the Enzyme Systems of Microorganisms
Ohta, Hiromichi,Tetsukawa, Hatsuki,Noto, Naoko
, p. 2400 - 2404 (2007/10/02)
Gluconobacter were found to be capable of oxidizing prochiral diols such as 2-substituted propane-1,3-diols 1 and 3-substituted pentane-1,5-diols 4 with distinction of pro-R and pro-S sites of the molecules, in that (-)-(R)-α-substituted β-hydroxypropionic acids 2 and (+)-(3S)-3-substituted δ-valerolactones 5 were obtained, respectively.Oxidation of 3-methylpentane-1,3,5-triol 11 afforded unnatural (+)-(S)-mevalonolactone 12.The steric bulkiness of the substituents on the prochiral center and the distance from the hydroxy group greatly affected the rate and the enantioselectivity of the reaction.
Abnormal metabolites of isoleucine in a patient with propionyl-CoA carboxylase deficiency
Sweetman,Weyler,Nyhan,de Cespedes,Loria,Estrada
, p. 198 - 207 (2007/10/05)
A number of previously unrecognized abnormal metabolites have been identified and quantitated in the urine of a patient with an inherited deficiency of propionyl CoA carboxylase. These included the isoleucine metabolites 2 methyl 3 hydroxybutyric acid and 2 methylacetoacetic acid. The isomers 3 hydroxyvaleric acid and 3 oxovaleric acid were found, which may be products of the condensation of propionyl CoA with acetyl CoA catalyzed by 3 oxoacyl CoA thiolases. Following a load of isoleucine, 2 methylbutyrylglycine was identified. This metabolite has not previously been observed in man.
