- REGIOSELECTIVE OXIDATION OF HETEROCYCLIC ALPHA-AMINO AMIDES
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The present invention relates to regioselective chemical and electrochemical processes for the preparation of an oxidized heterocyclic alpha-amino amide compounds. By applying specific catalysts or catalyst systems during chemical oxidation or by applying particular electrochemical oxidation conditions the present invention provides access to valuable alpha amino amide compounds, which are oxidized at the heterocyclic amino group by regioselective introduction of either a hydroxyl or a keto group. In a more particular embodiment, the present invention describes a chemical oxidation reaction, which advantageously is applicable in the enantioselective synthesis of valuable oxidized heterocyclic alpha-amino amide compounds, like levetiracetam, brivaracetam or the synthesis of piracetam. Another aspect of the present invention relates to a process for the electrochemical recycling of alkali perhalogenate oxidants as spent during said regioselective oxidation reactions of the invention. Still another aspect of the invention relates to the electrochemical preparation of perhalogenates.
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Page/Page column 87-88
(2021/10/30)
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- The sustainable synthesis of levetiracetam by an enzymatic dynamic kinetic resolution and an: Ex-cell anodic oxidation
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Levetiracetam is an active pharmaceutical ingredient widely used to treat epilepsy. We describe a new synthesis of levetiracetam by a dynamic kinetic resolution and a ruthenium-catalysed ex-cell anodic oxidation. For the enzymatic resolution, we tailored a high throughput screening method to identify Comamonas testosteroni nitrile hydratase variants with high (S)-selectivity and activity. Racemic nitrile was applied in a fed-batch reaction and was hydrated to (S)-(pyrrolidine-1-yl)butaneamide. For the subsequent oxidation to levetiracetam, we developed a ligand-free ruthenium-catalysed method at a low catalyst loading. The oxidant was electrochemically generated in 86% yield. This route provides a significantly more sustainable access to levetiracetam than existing routes. This journal is
- Arndt, Sebastian,Grill, Birgit,Schwab, Helmut,Steinkellner, Georg,Pogorev?nik, Ur?ka,Weis, Dominik,Nauth, Alexander M.,Gruber, Karl,Opatz, Till,Donsbach, Kai,Waldvogel, Siegfried R.,Winkler, Margit
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supporting information
p. 388 - 395
(2021/01/28)
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- Ionic Cocrystals of Etiracetam and Levetiracetam: The Importance of Chirality for Ionic Cocrystals
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A striking variety of anhydrous and hydrated ionic cocrystals (ICCs) of the enantiopure antiepileptic drug (AED) levetiracetam and of its racemic intermediate etiracetam with the pharmaceutically acceptable salts CaCl2 and MgCl2 was synthesized and structurally characterized. The difference in the interaction of enantiopure and racemic compounds of interest with the inorganic salts was investigated. Variable-temperature X-ray powder diffraction (VT-XRPD) and calorimetric analyses (TGA and DSC) of all obtained ICCs showed a significant improvement in thermal stability with respect to pure racetams.
- Song, Lixing,Shemchuk, Oleksii,Robeyns, Koen,Braga, Dario,Grepioni, Fabrizia,Leyssens, Tom
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p. 2446 - 2454
(2019/03/26)
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- Solid-state chiral resolution mediated by stoichiometry: Crystallizing etiracetam with ZnCl2
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Chiral resolution of racemic etiracetam was achieved via co-crystallization with ZnCl2. Depending on the amount of ZnCl2 either a stable racemic compound or a stable conglomerate can be obtained. Excess ZnCl2 triggers the quantitative conversion of the racemate into the conglomerate solid; this unprecedented behaviour was investigated through a racetam/ZnCl2/solvent phase diagram.
- Shemchuk, Oleksii,Song, Lixing,Robeyns, Koen,Braga, Dario,Grepioni, Fabrizia,Leyssens, Tom
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supporting information
p. 10890 - 10892
(2018/10/02)
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- Ugi Four-Center Three-Component Reaction as a Direct Approach to Racetams
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We report the synthesis of racetams, a diverse class of small molecule drugs, by means of the Ugi four-center three-component reaction (U4C-3CR). For the first time, γ-aminobutyric acid is employed as bifunctional input in the Ugi reaction. This protocol is simple, general, and allows one-pot access to a range of drugs and bioactive small molecules.
- Cioc, R?zvan C.,Schaepkens van Riempst, Lola,Schuckman, Peter,Ruijter, Eelco,Orru, Romano V. A.
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p. 1664 - 1674
(2017/03/21)
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- Peculiar Case of Levetiracetam and Etiracetam α-Ketoglutaric Acid Cocrystals: Obtaining a Stable Conglomerate of Etiracetam
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In this contribution, we demonstrate that it is possible to obtain the lactol tautomer of alpha-ketoglutaric acid (AKGA) in the solid state by cocrystallizing it with Leviteracetam, a chiral nootropic drug used to treat epilepsy. In addition, we show that a cocrystal can be isolated with the racemic equivalent of Levetiracetam, Etiracetam (Eti), in which AKGA stays in the keto-form. We also report the existence of a cocrystal conglomerate in the Etiracetam-AKGA system, which is more stable than the racemic cocrystal at room temperature. The existence of a stable conglomerate is put in relation to the enantiospecificity of the Levetiracetam cocrystals, which is likely related to the ability of the Etiracetam enantiomers to stabilize one lactol tautomer at a time in solution or to promote its formation by hydrogen bonding. By comparing the peculiarities of the system in hand to the general behavior of cocrystallizing chiral systems with and without zwitterionic coformers, we suggest that for a pseudoquaternary cocrystal (made up of two racemate compounds) to exist the pseudoternary combinations (made up of one racemate and an enantiomer of the second compound) should exist and the enantiomers of the two compounds should form a diastereomeric pair at the binary level, rather than behave enantiospecifically.
- George, Fanny,Norberg, Bernadette,Robeyns, Koen,Wouters, Johan,Leyssens, Tom
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p. 5273 - 5282
(2016/11/07)
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- Does chirality influence the tendency toward cocrystal formation?
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We performed a systematic cocrystal search for the enantiopure and racemic version of a selected active pharmaceutical ingredient, expecting that a coformer giving a cocrystal with a single enantiomer will also interact with the racemic mixture since they present identical functional groups prone to cocrystallization. We identified several novel cocrystals of levetiracetam and its racemic equivalent, etiracetam, using a wide variety of nonchiral coformers. Fourteen novel cocrystals of the enantiopure compound were obtained, whereas 18 of the racemic compound were identified. Out of these, 13 share a common coformer. A structural analysis indicates that in most cases the strongest hydrogen bonding interactions occur both in the enantiopure, as well as the racemic cocrystal, whereas van der Waals interactions, or less strong secondary hydrogen bonding interactions, lead to a differentiation of the final structure. On the basis of our work, we suggest an approach that could lead to a more optimal cocrystal screening of an enantiopure compound, especially when a limited amount of this compound is available. Starting with a screen of the racemic compound, the set of possible coformers for the enantiopure screen can be limited to those yielding a positive hit in the former screen. Doing so, our example shows an increase in efficiency from 10% to 72%.
- George, Fanny,Tumanov, Nikolay,Norberg, Bernadette,Robeyns, Koen,Filinchuk, Yaroslav,Wouters, Johan,Leyssens, Tom
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p. 2880 - 2892
(2014/06/23)
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- Ternary and quaternary phase diagrams: Key tools for chiral resolution through solution cocrystallization
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The goal of this contribution is to guide the reader through the construction and the understanding of quaternary phase diagrams in the pursuit of optimal conditions for a chiral resolution through cocrystallization in solution. The overall description will be illustrated by experimental results on a system involving RS-2-(2-oxopyrrolidin-1-yl) butanamide as chiral API to be separated, and S-mandelic acid as chiral coformer.
- Springuel, Geraldine,Collard, Laurent,Leyssens, Tom
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p. 7951 - 7958
(2013/10/01)
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- A synthesis of levetiracetam based on (S)-N-phenylpantolactam as a chiral auxiliary
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The synthesis of levetiracetam and its enantiomer by deracemization of (±)-2-bromobutyric acid using either (S)- or (R)-N-phenylpantolactam as chiral auxiliaries, followed by SN2 substitution of the bromine atom by a 2-oxopyrrolidin-1-yl group and amidation of the carboxylic acid, is described.
- Boschi, Francesca,Camps, Pelayo,Comes-Franchini, Mauro,Munoz-Torrero, Diego,Ricci, Alfredo,Sanchez, Laura
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p. 3739 - 3745
(2007/10/03)
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