Ingo B. Aumüller

Synthesis and tautomerization of benzo[cd]azulen-3-ones.

This report describes a type of tautomerization reaction that proceeds via isomerization of π-bonds across the azulene moieties of tricyclic benzo[cd]azulen-3-ones. The reaction mechanism shows similarities to an elimination reaction that was recently developed in our group. Furthermore, the facile four-step syntheses of the benzo[cd]azulen-3-ones, the starting materials for the tautomerization reactions, and computational analyses of the tautomerization reaction are included.

Tricyclic Benzo[cd]azulenes Selectively Inhibit Activities of Pim Kinases and Restrict Growth of Epstein-Barr Virus-Transformed Cells

Oncogenic Pim family kinases are often overexpressed in human hematopoietic malignancies as well as in solid tumours. These kinases contribute to tumorigenesis by promoting cell survival and by enhancing resistance against chemotherapy and radiation therapy. Furthermore, we have recently shown that they increase the metastatic potential of adherent cancer cells. Here we describe identification of tricyclic benzo[cd]azulenes and their derivatives as effective and selective inhibitors of Pim kinases. These compounds inhibit Pim autophosphorylation and abrogate the anti-apoptotic effects of Pim kinases. They also reduce cancer cell motility and suppress proliferation of lymphoblastoid cell lines infected and immortalized by the Epstein-Barr virus. Thus, these novel Pim-selective inhibitors provide promising compounds for both research and therapeutic purposes.

Coloring Carbohydrates: Investigation of Azulene Derivatives as Blue Protecting Groups

Coloring carbohydrate derivatives by a chromophore tag greatly facilitates all purification steps during a synthetic sequence, according to a methodology called “chromophore-supported purification” (CSP). Herein an Fmoc-analogous blue protective group for CSP is introduced, based on guaiazulene. Following a mechanistic rational, the synthesis and introduction of this new protecting group is shown, together with its removal under variable conditions and its application for the synthesis of glycoclusters of a glycopeptide and glycopeptoid type.

Nucleophilic Substitution of Hydrogen Facilitated by Quinone Methide Moieties in Benzo[cd]azulen-3-ones

The built-in o- and p-QM (QM = quinone methide) moieties in benzo[cd]azulen-3-ones account for an easy switch between the bridged 10π- and 6π-aromatic systems in organic synthesis. We report conjugate additions, oxidative nucleophilic substitutions of hydrogen, and reversible Michael additions under very mild conditions. In the presence of thiol nucleophiles, the protonated σH-adducts could be isolated and characterized. The typical preference for either the o- or p-QM moiety led to high regioselectivity. Furthermore, the inhibitory potency of the novel benzo[cd]azulenes against the human Pim-1 kinase was evaluated.