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Z. Naturforsch. 2013,
68b, 223 – 228
doi:10.5560/ZNB.2013-3030
Unexpected Formation of Thiophene-annulated Tetrahydro-3-benzazepines by Alkylation of Thiolactams with Ethyl Bromoacetate
1 Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Hittorfstraße 58–62, D-48149 Münster, Germany,
2 Organisch-Chemisches Institut der Westfälischen Wilhelms-Universität Münster, Corrensstr. 40, D-48149 Münster, Germany
Reprint requests to Prof. B. Wünsch. Tel.: +49-251-8333311. Fax: +49-251-8332144. E-mail:
wuensch@uni-muenster.de
Received January 14, 2013 / published online March 20, 2013
In order to synthesize enantiomerically pure tetrahydro-3-benzazepines with diverse substitution patterns, the lactams 3 were converted into thiolactams 4 upon treatment with Lawesson's reagent. Instead of an Eschenmoser sulfide contraction a thiophene annulation reaction occurred, when the thiolactams 4 were reacted with ethyl bromoacetate. Altogether, enantiomerically pure thiophene-annulated 3-benzazepines 7 were prepared in a very short reaction sequence (five reaction steps) starting from commercially available o-phenylenediacetic acid.
Key words: Tetrahydro-3-benzazepines, Enantiomerically Pure Compounds, Thiophene Annulation, Thiolactams, Lawesson's Reagent, Eschenmoser Sulfide Contraction, X-Ray Crystal Structure Analysis