Synthesis and Characterization of (–)-Menthyl Containing N-Alkyl Cycloimmonium Salts

Authors

  • Christina Hettstedt,

    1. Department of Chemistry, Ludwig-Maximilians University (LMU), Butenandtstrasse 5–13 (Haus D), 81377 Munich, Germany
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  • Wolfgang Betzl,

    1. Department of Chemistry, Ludwig-Maximilians University (LMU), Butenandtstrasse 5–13 (Haus D), 81377 Munich, Germany
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  • Dr. Konstantin Karaghiosoff

    Corresponding author
    1. Department of Chemistry, Ludwig-Maximilians University (LMU), Butenandtstrasse 5–13 (Haus D), 81377 Munich, Germany
    • Department of Chemistry, Ludwig-Maximilians University (LMU), Butenandtstrasse 5–13 (Haus D), 81377 Munich, Germany, Fax: +49-89-2180-77492
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  • Dedicated to Professor Wolfgang Beck on the Occasion of His 80th Birthday

  • Supporting Information for this article is available on the WWW under http://dx.doi.org/10.1002/zaac.201100451 or from the author.

Abstract

The reaction of 4-phenyl-2-aminothiazole or 2-amino pyridine with α-bromo acetic (–)-menthyl ester (2c) yields new N-alkyl cycloimmonium bromides (1c, 3) with the chiral (–)-menthyl substituent, which were isolated and fully characterized by 1H and 13C NMR spectroscopy for the first time. In addition, starting from 4-phenyl-2-aminothiazole, two further N-alkyl cycloimmonium bromides (1a, 1b) were prepared. The molecular and crystal structures of all three thiazole derived N-alkyl cycloimmonium bromides (1ac) were determined by single-crystal X-ray diffraction. In all cases the crystal structures are dominated by N–H···Br hydrogen bonds, which results in the formation of an extensive hydrogen bonded network in the crystal. Interestingly, in all structures S···Br distances shorter than the sum of the van der Waals radii are observed.

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