A Cyclic Continuous Process for Converting Conglomerates into Optically Pure Enantiomers by Crystallization and Dissolution with the Assistance of ‘Tailor-made’ Polymers

Zbaida, David; Lahav, Meir; Drauz, Karlheinz; Knaup, Günter L.; Kottenhahn, M.

doi:10.1016/s0040-4020(00)00465-8

Cited by 59 publications

(51 citation statements)

References 13 publications

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“…Zbaida et al have extended this work to soluble chiral polymers. [7,8] We have recently demonstrated the potential application of chiral double hydrophilic block copolymers in controlling chirality during the crystallization process. [9,10] We have shown that appropriate chiral polymers can slow down the formation of thermodynamically stable racemic crystals while favoring the formation of one of the pure enantiomeric crystals.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Crystallization on Chiral Polymeric Microspheres

Medina¹,

Goldshtein²,

Margel³

et al. 2007

Adv Funct Materials

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In this article, a new approach to chiral resolution based on enantioselective crystallization on chiral polymeric microspheres is presented. To demonstrate the approach, a new synthetic method is developed for the preparation of porous and hollow chiral polymeric microspheres. Chiral microspheres based on poly(N‐vinyl α‐L‐phenylalanine) (PV‐L‐Phe) are synthesized from uniform polystyrene (PS) microsphere templates by a single‐step swelling process. The chiral microspheres display a narrow size distribution, and their properties, especially the porosity, can be controlled by varying the synthesis conditions. The chiral discrimination ability of these chiral microspheres is studied for DL‐valine crystallization, as a model system for chiral racemic crystallization. X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) provide evidence for the crystallization of enantiopure crystals on the chiral polymeric microspheres. Optical rotation measurements during crystallization show an enatiomeric excess of ca. 25 % for L‐valine in the chiral microspheres. Although this excess is not yet very high, the basic principle of chiral discrimination by enantioselective crystallization on chiral microspheres is demonstrated.

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Section: Introductionmentioning

confidence: 99%

Enantioselective Crystallization on Chiral Polymeric Microspheres

Medina¹,

Goldshtein²,

Margel³

et al. 2007

Adv Funct Materials

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“…[54] Chiral aspects during the crystallization have been examined mainly by the Lahav group. [55][56][57] To examine the role of chirality, we investigated the influence of this polymer on the crystallization kinetics of the enantiopure amino acids. The presence of 0.1 wt % of PEG 4700 -PEI 1200 -S-iBAc results in a significant change in the crystallization kinetics, as revealed by measurements of the circular dichroism (l = 240 nm) of the supernatant solution over time (Figure 3).…”

mentioning

confidence: 99%

Polymer‐Induced Alignment of dl‐Alanine Nanocrystals to Crystalline Mesostructures

Wohlrab

Pinna

Antonietti

et al. 2005

Chemistry A European J

162

151

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Crystallization of DL-alanine by cooling of a supersaturated solution in the presence of a chiral double-hydrophilic block copolymer poly(ethylene glycol)-block-poly(ethylene imine)-S-isobutyric acid (PEG4700-PEI1200-S-iBAc) yields crystal superstructures with an astonishing morphology. Although analysis by light microscopy reveals these crystals to be apparently well facetted, electron microscopy shows that they consist of three-dimensionally, well-aligned nanocrystals that are scaffolded to a so-called mesocrystal. This mesocrystal is formed by polymer-mediated structuration, and provides evidence for the importance of mesoscopic events in a typical crystallization process.

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“…[106][107][108]). In einer aktuellen Arbeit [109] beschreiben die Autoren ein zyklisches Trennverfahren in Gegenwart eines maßgeschnei-derten enantiomerenreinen Polymers, das zu Unterschieden im Wachstums-und Auflçsungsverhalten der beiden Enantiomere führt und so die Racematspaltung unterstützt.…”

Section: Klassische Racematspaltungunclassified

Verfahren zur Enantiomerentrennung

Lorenz

Seidel‐Morgenstern

2014

Angewandte Chemie

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Die Verfügbarkeit reiner Enantiomere ist von steigender Bedeutung für die pharmazeutische Industrie sowie auch für die Agrochemie und Biotechnologie. Generell gibt es zwei konkurrierende Ansätze zur Gewinnung von reinen Enantiomeren. Der “chirale” Ansatz basiert auf der Entwicklung einer asymmetrischen Synthese, die selektiv eines der Enantiomere liefert. Der “racemische” Ansatz basiert auf der Trennung eines Gemischs der beiden Enantiomere, wobei hier in den letzten Jahren bemerkenswerte Fortschritte erzielt werden konnten. Dieser Aufsatz fokussiert insbesondere auf enantioselektive Kristallisationsprozesse und präparative Chromatographie, einschließlich hybrider Trennprozesse und der zusätzlichen Integration von Racemisierungsschritten. Zur Illustration dienen mehrere in unserem Arbeitskreis untersuchte Trennungen.

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A Cyclic Continuous Process for Converting Conglomerates into Optically Pure Enantiomers by Crystallization and Dissolution with the Assistance of ‘Tailor-made’ Polymers

Cited by 59 publications

References 13 publications

Enantioselective Crystallization on Chiral Polymeric Microspheres

Enantioselective Crystallization on Chiral Polymeric Microspheres

Polymer‐Induced Alignment of dl‐Alanine Nanocrystals to Crystalline Mesostructures

Verfahren zur Enantiomerentrennung

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