10327-08-9Relevant academic research and scientific papers
Catalytic Cracking of Lactide and Poly(Lactic Acid) to Acrylic Acid at Low Temperatures
Terrade, Frédéric G.,van Krieken, Jan,Verkuijl, Bastiaan J. V.,Bouwman, Elisabeth
, p. 1904 - 1908 (2017)
Despite being a simple dehydration reaction, the industrially relevant conversion of lactic acid to acrylic acid is particularly challenging. For the first time, the catalytic cracking of lactide and poly(lactic acid) to acrylic acid under mild conditions is reported with up to 58 % yield. This transformation is catalyzed by strong acids in the presence of bromide or chloride salts and proceeds through simple SN2 and elimination reactions.
One-step radiosynthesis of 4-nitrophenyl 2-[18F]fluoropropionate ([18F]NFP); Improved preparation of radiolabeled peptides for PET imaging
Haskali, Mohammad B.,Roselt, Peter D.,Karas, John A.,Noonan, Wayne,Wichmann, Christian W.,Katsifis, Andrew,Hicks, Rodney J.,Hutton, Craig A.
, p. 726 - 730 (2013)
The versatile 18F-labeled prosthetic group, 4-nitrophenyl 2-[18F]fluoropropionate ([18F]NFP), was synthesized in a single step in 45 min from 4-nitrophenyl 2-bromopropionate, with a decay corrected radiochemical yield of 26.2% ± 2.2%. Employing this improved synthesis of [18F]NFP, [18F]GalactoRGD - the current 'gold standard' tracer for imaging the expression of αVβ 3 integrin - was prepared with high specific activity in 90 min and 20% decay corrected radiochemical yield from [18F]fluoride. 4-Nitrophenyl 2-[18F]fluoropropionate ([18F]NFP), was synthesized in a single radiochemical step in 45 minutes and 26% d.c. radiochemical yield from 4-nitrophenyl 2-bromopropionate. Employing this improved synthesis of [18F]NFP, [18F]GalactoRGD was prepared with high specific activity in 90 minutes and 20% d.c. radiochemical yield from [18F]fluoride. Copyright
Specific esterase activity of subtilisin toward esters of α-haloacids
Pugniere,Juan, C. San,Previero
, p. 4883 - 4886 (1990)
Esters of α-haloacids are specific substrates for subtilisin which catalyses their hydrolysis in aqueous media. The same esters undergo transesterifications in organic solvents in the presence of subtilisin immobilized on an alumina-phosphate complex.
Difference in the behavior of methyl (S)-α-bromopropionate in its addition to trimethylvinylsilane depending on the method of initiation
Terentiev,Vasilieva,Kuz'mina,Orlova,Ikonnikov,Mysov,Kolehmainen,Laihia,Belokon'
, p. 676 - 679 (1996)
The addition of methyl (S)-2-bromopropionate to trimethylvinylsilane initiated by systems based on iron pentacarbonyl affords a racemic adduct and is accompanied by racemization of the unreacted chiral ester. In the presence of benzoyl peroxide, the reaction proceeds similarly, but no racemization of the starting chiral ester occurs.
Atropselective Dibrominations of a 1,1′-Disubstituted 2,2′-Biindolyl with Diverging Point-to-Axial Asymmetric Inductions. Deriving 2,2′-Biindolyl-3,3′-diphosphane Ligands for Asymmetric Catalysis
Baumann, Thomas,Brückner, Reinhard
, p. 4714 - 4719 (2019)
On the 1H NMR timescale, 2,2′-biindolyls with (R)-configured (1-alkoxyprop)-2-yl, (1-hydroxyprop)-2-yl, or (1-siloxyprop)-2-yl substituents at C-1 and C-1′ are atropisomerically stable at 30 °C. A 2,2′-biindolyl (R,R)-17 a of that kind and achiral (!) brominating reagents gave the atropisomerically stable 3,3′-dibromobiindolyls (M)- and/or (P)-18 a at best atropselectively—because of point-to-axial asymmetric inductions—and atropdivergently, exhibiting up to 95 % (M)- and as much (P)-atropselectivity. This route to atropisomerically pure biaryls is novel and should extend to other substrates and/or different functionalizations. The dibromobiindolyls (M)- and (P)-18 a furnished the biindolyldiphosphanes (M)- and (P)-14 without atropisomerization. These syntheses did not require the resolution of a racemic mixture, which distinguishes them from virtually all biaryldiphosphane syntheses known to date. (M)- and (P)-14 acted as ligands in catalytic asymmetric allylations and hydrogenations. Remarkably, the β-ketoester rac-25 c was hydrogenated trans-selectively with 98 % ee; this included a dynamic kinetic resolution.
Zwitterionic Hydrobromic Acid Carriers for the Synthesis of 2-Bromopropionic Acid from Lactide
Kehrer, Matthias,Mehler, Julian,Taccardi, Nicola,Nagengast, Jens,Kadar, Julian,Collias, Dimitris,Dziezok, Peter,Wasserscheid, Peter,Albert, Jakob
, p. 1063 - 1072 (2018)
A convenient and highly efficient way of synthesizing 2-bromopropionic acid (2-BrPA) from lactide is presented. The procedure uses ionic liquids obtained from the addition of HBr to ammonium-based zwitterions as the solvent and bromination agent. The buffered HBr acidity, high polarity, and charge stabilizing character of the ionic liquid (IL) enable the synthesis of 2-BrPA with excellent selectivity. The best results are obtained with an imidazolium-based IL, that is, 1-(4-butanesulfonic acid)-3-methylimidazolium bromide ([MIMBS]Br). The HBr loading and water content of the IL are crucial parameters for the bromination reaction. The formed 2-BrPA product can be selectively isolated by extraction from the IL, and the unconverted substrate remains in the [MIMBS]Br IL for the next run. Successful recycling of the IL over four cycles is demonstrated.
A simple and efficient method of preparing α-bromo carboxylic acids
Zhang, Lian Hao,Duan, Jianxin,Xu, Yuelian,Dolbier Jr., William R.
, p. 9621 - 9622 (1998)
A new and convenient method for α-bromination of aliphatic carboxylic acids is reported. Heating carboxylic acids for 16 hours at 85 °C in trifluoroacetic acid with 1.5 equivalents of N-bromosuccinimide and a catalytic amount of concentrated H2SO4 leads to good yields of the respective α-bromocarboxylic acids.
Enantioselective Construction of Axially Chiral Azepine-Containing P,N-Ligands from l -Alanine
Zhang, Jinlong,Gao, Zeng,Qian, Jinlong,Yang, Huameng,He, Maosheng,Jiang, Gaoxi
supporting information, p. 7814 - 7818 (2021/10/20)
A family of axially chiral azepine-containing seven-membered cyclic P,N-ligands (named Indole-azepinap) have been prepared by using l-alanine as an original chirality source. The direct chromatographic separation of two diastereomeric phosphine oxides on silica gel enabled these ligands to be easy available, allowing further structural and electronic modifications. Preliminary application of these Indole-azepinaps has been demonstrated in a Pd-catalyzed asymmetric allylic alkylation with high yields and moderate enantioselectivities.
1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids
Reed, John H.,Cramer, Nicolai
, p. 4262 - 4266 (2020/07/13)
The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.
TRICYCLIC COMPOUNDS HAVING SULFINYL AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
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Paragraph 0069, (2020/01/02)
It is intended to provide a compound that exhibits a wide antibacterial spectrum against various bacteria including gram-negative bacteria, and a pharmaceutical composition having an antibacterial activity against carbapenem-resistant bacteria.
