Synthesis of Six-Membered Rings and Inhibitors of Protein Kinases

Alexandros Kiriazis

Research output: ThesisDoctoral ThesisCollection of Articles


The six-membered rings have a priviledged presence in both natural products and synthetic compounds such as drug molecules. Multiple methods to prepare them in the laboratory have been developed. The Diels-Alder reaction provides several pathways toward the construction of substituted six-membered rings with a high degree of regio-, diastereo- and enantioselectivity. It can be considered to be the most important and powerful carbon-carbon bond-forming reaction of all, in synthetic organic chemistry.

A practical synthetic method for the preparation of hexahydrocinnolines was developed here, as part of continuing research on polymer-supported pericyclic reactions in preparation of biologically interesting compounds. Some cinnoline derivatives from the literature were reported to show interesting biological properties, such as antimicrobial activity and inhibition of cancer cell lines. Hexahydro-1,2,4-triazolocinnoline-1,3-diones and related compounds were synthesized via aza Diels-Alder reaction on solid-phase.

Protein kinases are key regulators of cell function that constitute one of the largest and most functionally diverse gene families. By adding phosphate groups to substrate proteins, kinase driven phosphorylation plays a significant role in a wide range of cellular processes. More than 500 protein kinase genes are present in the the human genome, constituting about 2% of all human genes. They regulate many cellular processes such as growth, differentiation, and proliferation. Protein kinases are seen as potential therapeutic targets since their mutation and dysregulation is causal in multiple human diseases, including metabolic, immunological disorders, and cancer. The consistent structure of the catalytic site among protein kinases sets limits for the development of protein kinase inhibitors. Some protein kinases, however, have regulatory domains as part of their structure, such as protein kinase C (PKC), whose regulatory (C1) domain is unique and is found only in a small number of kinases. This offers a selectivity advantage, thus making the C1-domain an attractive drug target. In fact, the utilization of the the X-ray crystal structure of the PKCδ C1b domain, with molecular modeling, led to the discovery, in this work, of novel C1 domain ligands, the tricyclic γ-amino alcohols. Synthesis of these compounds was achieved by the utilization of the Diels-Alder reactions.

In the process of modifying a naturally occurring deep-blue colored hydrocarbon guaiazulene, a novel aminoguaiazulene derivative was synthesized. This novel derivative undergoes ring annulation reactions with 1,2-dicarbonyl reagents to yield tricyclic δ-lactams, types of benzo[cd]azulenes. Benzo[cd]azulenes derived from guaiazulene, are colorful synthetic carbocyclics with interesting chemical and biological properties. Some of the benzo[cd]azulenes synthesized in this study were recently characterized as selective Pim kinase inhibitors. Pim kinases have become intriguing targets for cancer therapy that possess unique structural features, among protein kinases, that offer a great potential in the design of selective Pim-inhibitors. Based on the promising Pim-kinase inhibition results from multiple cell-based assays, a further modification of the benzo[cd]azulenes was conducted, where some interesting findings in their chemical behavior were observed; new phenolic benzo[cd]azulene compounds were formed, with potent Pim-inhibitory activities. The benzo[cd]azulenes developed in this study were found to be useful research compounds, potential Pim-selective kinase inhibitors, and putative anti-cancer drug candidates. The new synthetic methods detailed in this study will be valuable tools in the further development of additional benzo[cd]azulenes and related systems in the future.
Original languageEnglish
Place of PublicationHelsinki
Print ISBNs978-952-10-8192-7
Electronic ISBNs978-952-10-8193-4
Publication statusPublished - 2012
MoE publication typeG5 Doctoral dissertation (article)

Fields of Science

  • 317 Pharmacy

Cite this