Extreme Liquid Chromatographic Separation Effects in the Case of Diastereomeric Amides Containing Polar Substituents

Authors

  • Dr. Günter Helmchen,

    Corresponding author
    1. Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
    • Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
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  • Dipl.-Chem. Günter Nill,

    1. Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
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  • Dipl.-Chem. Dieter Flockerzi,

    1. Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
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  • Willi Schühle,

    1. Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
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  • Dr. Mohamed S. K. Youssef

    1. Institut für Organische Chemie, Biochemie und Isotopenforschung der Universität, Pfaffenwaldring 55, D-7000 Stuttgart 80 (Germany)
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  • Direced Resolution of Enantiomers via Liquid Chromatography of Diastereomeric Derivatives, Part 4. This work was supported by the Deutsche Forschungsgemeinschaft (Projekt He 880/6).—Part 3: [1a].

Abstract

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Routine separations of enantiomers may soon be common laboratory practice. On the basis of chromatographic data, four postulates were derived which serve as guidelines in the search for the structural feature of the amides (1)/(2) necessary for high separation factors α. The highest value of α = 5.77 has been found for (1)/(2), R1[DOUBLE BOND](CH2)2OH, A1[DOUBLE BOND]CH2OH, R2=A2[DOUBLE BOND]Ph; this is for separation on silica gel! Separations with α≳2 are possible on simple columns.

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