602261-98-3Relevant academic research and scientific papers
Cell-Based Optimization of Covalent Reversible Ketoamide Inhibitors Bridging the Unprimed to the Primed Site of the Proteasome β5 Subunit
Stubba, Daniel,Bensinger, Dennis,Steinbacher, Janika,Proskurjakov, Lilia,Salcedo Gómez, álvaro,Schmidt, Uwe,Roth, Stefan,Schmitz, Katja,Schmidt, Boris
supporting information, p. 2005 - 2022 (2019/11/22)
The ubiquitin-proteasome system (UPS) is an established therapeutic target for approved drugs to treat selected hematologic malignancies. While drug discovery targeting the UPS focuses on irreversibly binding epoxyketones and slowly-reversibly binding boronates, optimization of novel covalent-reversibly binding warheads remains largely unattended. We previously reported α-ketoamides to be a promising reversible lead motif, yet the cytotoxic activity required further optimization. This work focuses on the lead optimization of phenoxy-substituted α-ketoamides combining the structure-activity relationships from the primed and the non-primed site of the proteasome β5 subunit. Our optimization strategy is accompanied by molecular modeling, suggesting occupation of P1′ by a 3-phenoxy group to increase β5 inhibition and cytotoxic activity in leukemia cell lines. Key compounds were further profiled for time-dependent inhibition of cellular substrate conversion. Furthermore, the α-ketoamide lead structure 27 does not affect escape response behavior in Danio rerio embryos, in contrast to bortezomib, which suggests increased target specificity.
Peroxydicarbonate-mediated oxidation of N-(ortho-aryloxyphenyl) and N-(ortho-arylaminophenyl)aldimines
Leardini, Rino,McNab, Hamish,Nanni, Daniele
, p. 12143 - 12158 (2007/10/02)
Imidoyl radicals 5, obtained from imines 1 by hydrogen abstraction with di-iso-propyl peroxydicarbonate (DPDC), give dibenzoxazepines through 7-membered ring closure. A competitive 6-membered cyclisation leads to intermediate spirocyclohexadienyl radicals that rearrange to aryloxy radicals; this process entails a novel 1,5-aryl radical translocation from an oxygen to a carbon atom and leads to benzophenones, benzoxazoles, and biphenyls. The possibility that the oxazepines arise from rearrangement of the 6-membered-ring-closure intermediates is discussed. With imine 1e, the formation of 5e occurs to a minor extent owing to a side-reaction of the iso-propoxycarbonyloxy radicals, which give rise to an intermolecular aromatic ipso-substitution on the benzenic ring linked to the two oxygen atoms. The 1,5-aryl migration can also be observed with imidoyl radicals generated by radical addition to 2-phenoxyisocyanobenzene. In contrast, the reactions of imines 2 with DPDC do not afford imidoyl radicals, as abstraction of the iminic hydrogen is slower than oxidation of the methyl group: this process entails the formation of carbamoyl radicals, which cyclise onto the carbonitrogen double bond, furnishing quinoxalinone derivatives, or loose carbon monoxide to yield benzimidazoles through ring closure of aminyl radicals. A novel cyclisation of a nitrogen-centred radical onto a formamido group could account for the formation of a benzimidazolinone derivative.
