Homo‐ and Heterochirality in Crystals

Levkin, Pavel A.; Torbeev, Vladimir Yu.; Lenev, Denis A.; Kostyanovsky, Remir G.

doi:10.1002/0471785156.ch4

Cited by 28 publications

(18 citation statements)

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“…With regard to this phenomenon, all reviewers are in agreement that the present level of theory has given no way to solve the problem of homochiral crystallization against heterochiral crystallization, while the understanding of the factors controlling the two enantiomers' behavior upon solution or melt crystallization is rather limited. [2][3][4] In the absence of a rigorous theory, we believe that investigations of the crystal structure changes with chemical structure variations in a series of closely related compounds would be fruitful. The members of such a series must be selected in such a way that every compound would have minimal but regular distinctions from each other.…”

Section: Introductionmentioning

confidence: 99%

From racemic compounds through metastable to stable racemic conglomerates: crystallization features of chiral halogen and cyano monosubstituted phenyl glycerol ethers

Бредихин

Бредихина

Akhatova

et al. 2009

Tetrahedron: Asymmetry

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Section: Introductionmentioning

confidence: 99%

From racemic compounds through metastable to stable racemic conglomerates: crystallization features of chiral halogen and cyano monosubstituted phenyl glycerol ethers

Бредихин

Бредихина

Akhatova

et al. 2009

Tetrahedron: Asymmetry

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“…Leistungsfä-higkeit und Grenzen der Methode sind außerdem in einem Beitrag von Levilain und Coquerel erläutert. [100] Das Verständnis des Phänomens der Konglomeratbildung, auch als spontane Racematspaltung bei Kristallisation bezeichnet, ist als "eine der grçßten Herausforderungen in der Stereochemie" [101] beschrieben, und mehrere Über-sichtsartikel widmen sich diesem Thema (z. B. Lit.…”

Section: Klassische Racematspaltungunclassified

“…B. Lit. [101,102] [105] Studien zum Einsatz "maßgeschneider-ter" Additive zur selektiven Hemmung der Kristallisation des ungewünschten Enantiomers und damit einer robusteren Trennung wurden insbesondere von der Arbeitsgruppe um Lahav und Leiserowitz durchgeführt (z. B. Lit.…”

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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“…[23][24][25][26] These multi-epitaxies between enantiomers create bi-dimensional racemic compounds which, for reasons not yet understood, do not expand in the third dimension. Actually there is no conceptual limit between these repetitive epitaxies and the corresponding racemic co-crystal (Figure 13.10).…”

Section: Example 3: a Hybrid Salt-co-crystalmentioning

confidence: 99%

Limits of the Co-crystal Concept and Beyond

Coquerel

2011

Pharmaceutical Salts and Co-Crystals

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In this chapter, views of co-crystals are broadened. Indeed, any classification has its limits and, clearly, the thermodynamics of heterogeneous equilibria can help to replace the concept of the co-crystal in a more general perspective. Co-crystals are nothing other than intermediate compounds. Nevertheless, the concept suffers from intrinsic uncertainties due to the numerous situations in which they can occur such as the continuum between solvate and co-crystals, hybrid salt-co-crystals, multi-epitaxy and so on. It is even possible to find the same partners with simultaneously salt-like and co-crystal-like relationships in a given crystal structure. Therefore, rather than creating questionable terms and maintaining endless semantic debates with poor added value, the scientific community should concentrate more on the three long lasting problems related to intermediate compounds listed below: 1. Prediction of intermediate compounds: indeed, apart from statistical trends (e.g. racemic compounds as detailed in this chapter), there is no way to predict the existence of an intermediate compound with acceptable reliability. 2. Prediction of the attributes of these intermediate compounds: to date the connection between structures and properties is very weak despite the evident interest. 3. How to design a process to obtain those intermediate phases with a good yield and minimum side products? Moreover these processes should fulfil the specifications for the final products such as crystallinity, crystal size distribution, morphology, and so on. These questions are really meaningful from an industrial perspective and for advancing knowledge in the organic solid state.

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Homo‐ and Heterochirality in Crystals

Cited by 28 publications

References 0 publications

From racemic compounds through metastable to stable racemic conglomerates: crystallization features of chiral halogen and cyano monosubstituted phenyl glycerol ethers

From racemic compounds through metastable to stable racemic conglomerates: crystallization features of chiral halogen and cyano monosubstituted phenyl glycerol ethers

Verfahren zur Enantiomerentrennung

Limits of the Co-crystal Concept and Beyond

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