19019-21-7Relevant articles and documents
Relay Catalysis by Achiral Borane and Chiral Phosphoric Acid in the Metal-Free Asymmetric Hydrogenation of Chromones
Chen, Jingjing,Gao, Bochao,Feng, Xiangqing,Meng, Wei,Du, Haifeng
supporting information, p. 8565 - 8569 (2021/11/13)
A strategy of relay catalysis by achiral borane and chiral phosphoric acid was successfully developed for the asymmetric hydrogenation of chromones, giving the desired products in high yields with up to 95% ee. Achiral borane and chiral phosphoric acid are highly compatible in this reaction. The achiral borane acts as a Lewis acid for the first-step hydrogenation, and the chiral phosphoric acid acts as an effective chiral proton shuttle to control the enantioselectivity.
Structure-activity relationships of novel salicylaldehyde isonicotinoyl hydrazone (SIH) analogs: Iron chelation, anti-oxidant and cytotoxic properties
Potuckova, Eliska,Hruskova, Katerina,Bures, Jan,Kovarikova, Petra,Spirkova, Iva A.,Pravdikova, Katerina,Kolbabova, Lucie,Hergeselova, Tereza,Haskova, Pavlna,Jansova, Hana,Machacek, Miloslav,Jirkovska, Anna,Richardson, Vera,Lane, Darius J. R.,Kalinowski, Danuta S.,Richardson, Des R.,Vavrova, Katerina,Simunek, Tomas
, (2015/02/19)
Salicylaldehyde isonicotinoyl hydrazone (SIH) is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability). Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O), which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.
Targeting the gatekeeper residue in phosphoinositide 3-kinases
Alaimo, Peter J.,Knight, Zachary A.,Shokat, Kevan M.
, p. 2825 - 2836 (2007/10/03)
A single residue in the ATP binding pocket of protein kinases-termed the gatekeeper-has been shown to control sensitivity to a wide range of small molecule inhibitors (Chem. Biol. 2004, 11, 691; Chem. Biol. 1999, 6, 671). Kinases that possess a small side chain at this position (Thr, Ala, or Gly) are readily targeted by structurally diverse classes of inhibitors, whereas kinases that possess a larger residue at this position are broadly resistant. Recently, lipid kinases of the phosphoinositide 3-kinase (PI3-K) family have become the focus of intense research interest as potential drug targets (Chem. Biol. 2003, 10, 207; Curr. Opin. Pharmacol. 2003, 3, 426). In this study, we identify the residue that corresponds structurally to the gatekeeper in PI3-Ks, and explore its importance in controlling enzyme activity and small molecule sensitivity. Isoleucine 848 of p110α was mutated to alanine and glycine, but the mutated kinase was found to have severely impaired enzymatic activity. A structural bioinformatic comparison of this kinase with its yeast orthologs identified second site mutations that rescued the enzymatic activity of the I848A kinase. To probe the dimensions of the gatekeeper pocket, a focused panel of analogs of the PI3-K inhibitor LY294002 was synthesized and its activity against gatekeeper mutated and wild-type p110α was assessed.