598-72-1Relevant articles and documents
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.
METHOD OF MAKING ACRYLIC ACID FROM LACTIC ACID OR LACTIDE USING MOLTEN SALT CATALYSTS
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Page/Page column 37; 38; 39; 41, (2018/09/28)
A method of making acrylic acid in liquid phase by contacting a feed stream containing lactic acid, lactide, or mixtures thereof with a molten salt catalyst comprising a protic ionic liquid (PIL), which contains a bromide anion (Br-), is provided.
Catalytic Bromination of Alkyl sp3C-H Bonds with KBr/Air under Visible Light
Zhao, Mengdi,Lu, Wenjun
supporting information, p. 5264 - 5267 (2018/09/12)
Alkyl sp3C-H bonds of cycloalkanes and functional branch/linear alkanes have been successfully brominated with KBr using air or O2 as an oxidant at room temperature to 40 °C. The reactions are carried out in the presence of catalytic NaNO2 in 37% HCl (aq)/solvent under visible light, combining aerobic oxidations and photochemical radical processes. For various alkane substrates, CF3CH2OH, CHCl3, or CH2Cl2 is employed as an organic solvent, respectively, to enhance the efficiency of bromination.
METHODS OF MAKING ACRYLIC ACID FROM LACTIC ACID OR ITS DERIVATIVES IN LIQUID PHASE
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Page/Page column 66; 67, (2018/02/28)
Methods for making acrylic acid, acrylic acid derivatives, or mixtures thereof by contacting a feed stream containing lactic acid, lactic acid derivatives, or mixtures thereof with a molten salt catalyst comprising an ionic liquid (IL) and an acid in liquid phase are provided.
CATALYSTS FOR MAKING ACRYLIC ACID FROM LACTIC ACID OR ITS DERIVATIVES IN LIQUID PHASE
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Page/Page column 66, (2018/02/28)
Catalysts for the dehydration of lactic acid, lactic acid derivatives, or mixtures thereof to acrylic acid, acrylic acid derivatives, or mixtures thereof in liquid phase comprising an ionic liquid (IL) and an acid are provided.
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 (2018/03/01)
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.
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 (2017/05/16)
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.
Preparation methods of tiopronin and zinc complex of tiopronin
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Paragraph 0026; 0027, (2017/02/24)
The invention discloses preparation methods of tiopronin and zinc complex of tiopronin and belongs to the technical field of a medicine compound for relieving acute/chronic liver diseases. The technical scheme is characterized in that the formula is shown in the specification. The operation is simple, the cost of raw materials is low, the repeatability of experimental results of a process route is higher, and the production cost can be remarkably reduced.
Enantioselective construction of tetrasubstituted stereogenic carbons through bronsted base catalyzed michael reactions: α′-hydroxy enones as key enoate equivalent
Badiola, Eider,Fiser, Bla,Gmez-Bengoa, Enrique,Mielgo, Antonia,Olaizola, Iurre,Urruzuno, Iaki,Garca, Jess M.,Odriozola, Jos M.,Razkin, Jess,Oiarbide, Mikel,Palomo, Claudio
supporting information, p. 17869 - 17881 (2015/02/19)
Catalytic and asymmetric Michael reactions constitute very powerful tools for the construction of new C-C bonds in synthesis, but most of the reports claiming high selectivity are limited to some specific combinations of nucleophile/electrophile compound types, and only few successful methods deal with the generation of all-carbon quaternary stereocenters. A contribution to solve this gap is presented here based on chiral bifunctional Bronsted base (BB) catalysis and the use of α′-oxy enones as enabling Michael acceptors with ambivalent H-bond acceptor/donor character, a yet unreported design element for bidentate enoate equivalents. It is found that the Michael addition of a range of enolizable carbonyl compounds that have previously demonstrated challenging (i.e., α-substituted 2-oxindoles, cyanoesters, oxazolones, thiazolones, and azlactones) to α′-oxy enones can afford the corresponding tetrasubstituted carbon stereocenters in high diastereo- and enantioselectivity in the presence of standard BB catalysts. Experiments show that the α′-oxy ketone moiety plays a key role in the above realizations, as parallel reactions under identical conditions but using the parent α,β-unsaturated ketones or esters instead proceed sluggish and/or with poor stereoselectivity. A series of trivial chemical manipulations of the ketol moiety in adducts can produce the corresponding carboxy, aldehyde, and ketone compounds under very mild conditions, giving access to a variety of enantioenriched densely functionalized building blocks containing a fully substituted carbon stereocenter. A computational investigation to rationalize the mode of substrate activation and the reaction stereochemistry is also provided, and the proposed models are compared with related systems in the literature.
Synthesis of enantiomerically enriched-bromonitriles from amino acids
Tka, Najeh,Kraem, Jamil,Hassine, Bechir Ben
, p. 735 - 743 (2013/01/15)
Two methods were investigated for the preparation of six chiral-bromonitriles with different optic purities. The nitrous deamination of amino acids gives-bromoacids, which react with chlorosulfonyl isocyanate followed by triethylamine to afford-bromonitriles with moderate enantiomeric excess. However, the dehydration of corresponding-bromoamids using thionyl chloride gives-bromonitriles with good enantiomeric excess up to 94%. The use of phosphoryl chloride instead of thionyl chloride results in more than 30% racemization as determined by high-performance liquid chromatograpic analysis.
