13031-60-2Relevant articles and documents
Spin-labeled derivatives of cardiotonic steroids as tools for characterization of the extracellular entrance to the binding site on Na+,K+-ATPase
Guo, Jin-Hua,Jiang, Ren-Wang,Andersen, Jacob Lauwring,Esmann, Mikael,Fedosova, Natalya U.
, p. 2292 - 2305 (2018)
The information obtained from crystallized complexes of the Na+,K+-ATPase with cardiotonic steroids (CTS) is not sufficient to explain differences in the inhibitory properties of CTS such as stereoselectivity of CTS binding or effect of glycosylation on the preference to enzyme isoforms. The uncertainty is related to the spatial organization of the hydrophilic cavity at the entrance of the CTS-binding site. Therefore, there is a need to supplement the crystallographic description with data obtained in aqueous solution, where molecules have significant degree of flexibility. This work addresses the applicability of the electron paramagnetic resonance (EPR) method for the purpose. We have designed and synthesized spin-labeled compounds based on the cinobufagin steroid core. The length of the spacer arms between the steroid core and the nitroxide group determines the position of the reporting group (N-O) confined to the binding site. High affinity to Na+,K+-ATPase is inferred from their ability to inhibit enzymatic activity. The differences between the EPR spectra in the absence and presence of high ouabain concentrations identify the signature peaks originating from the fraction of the spin labels bound within the ouabain site. The degree of perturbations of the EPR spectra depends on the length of the spacer arm. Docking of the compounds into the CTS site suggests which elements of the protein structure might be responsible for interference with the spin label (e.g., steric clashes or immobilization). Thus, the method is suitable for gathering information on the cavity leading to the CTS-binding site in Na+,K+-ATPase in all conformations with high affinity to CTS.
Carbonylative lactonization via carbonyl oxygen attack: A short and selective total synthesis of uncinine and its analogues
Fáková, Helena,Pour, Milan,Kune?, Ji?í,?enel, Petr
, p. 8137 - 8140 (2005)
A novel cytotoxic butenolide alkaloid, uncinine, has been synthesized for the first time in 8 steps from propargyl alcohol. The sequence features a mild and efficient tandem carbonylative lactonization of a β-iodoenone precursor using an inorganic base at 1 atm CO, and an indirect attachment of the pyrrolidinone ring via nucleophilic substitution with methyl γ-aminobutyrate.
Gossypol with Hydrophobic Linear Esters Exhibits Enhanced Antitumor Activity as an Inhibitor of Antiapoptotic Proteins
Lu, Yuzhi,Wu, Shuangchan,Yue, Yuan,He, Si,Li, Jun,Tang, Jun,Wang, Wei,Zhou, Hai-Bing
, p. 1185 - 1190 (2016)
A series of gossypol Schiff bases that were derived from unnatural linear amino acid methyl esters were identified and found to be much more potent than gossypol and ABT-199 in terms of anticancer activity. This is the first example of gossypol Schiff bases with increased activity. The investigation of the Schiff base side chain of gossypol revealed that the unique anticancer effect was achieved by the introduction of hydrophobic ester groups. The optimized products showed low micromolar pan antitumor activities against NCI-60 tumor cell lines, which is promising for further drug development. Studies on the preliminary mechanism of action for their cellular activities was also carried out with antiapoptotic protein (Bcl-2 and Mcl-1) inhibition FP assays. The molecular modeling analysis demonstrated a possible binding mode for these compounds with Bcl-2, which could explain the binding affinity of the novel gossypol Schiff bases with these proteins.
Acetyl chloride-methanol as a convenient reagent for: A) quantitative formation of amine hydrochlorides; B) carboxylate ester formation; C) mild removal of N-t-Boc-protective group
Nudelman, Ayelet,Bechor, Yosi,Falb, Eliezer,Fischer, Bilha,Wexler, Barry A.,Nudelman, Abraham
, p. 471 - 474 (1998)
Hydrogen chloride quatitativaly generated in situ by the addition of acetyl chloride to alcoholic solutions is a useful reagent for carboxylic acid esterification, N-t-Boc deprotection and phosphoramide solvolysis reactions.
Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts
Kervefors, Gabriella,Kersting, Leonard,Olofsson, Berit
supporting information, p. 5790 - 5795 (2021/03/08)
A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
Structure-activity relationship and molecular modelling studies of quinazolinedione derivatives MMV665916 as potential antimalarial agent
Albrecht, Sébastien,Florent, Isabelle,Mouray, Elisabeth,Mourot, Laura,Schmitt, Marjorie,Spichty, Martin
supporting information, (2021/11/22)
A series of new quinazolinedione derivatives have been readily synthesized and evaluated for their in vitro antiplasmodial growth inhibition activity. Most of the compounds inhibited P. falciparum FcB1 strain in the low to medium micromolar concentration. The 2-ethoxy 8ag’, 2-trifluoromethoxy 8ai’ and 4-fluoro-2-methoxy 8ak’ showed the best inhibitory activity with EC50 values around 5 μM and were non-toxic to the primary human fibroblast cell line AB943. However, these compounds were less potent than the original hit MMV665916, which showed remarkable growth inhibition with EC50 value of 0.4 μM and presented the highest selectivity index (SI > 250). In addition, a novel approach for determining the docking poses of these quinazolinedione derivatives with their potential protein target, the P. falciparum farnesyltransferase PfFT, was investigated.
High-Fidelity End-Functionalization of Poly(ethylene glycol) Using Stable and Potent Carbamate Linkages
Cen, Jie,Hu, Jinming,Li, Lei,Liu, Guhuan,Liu, Shiyong,Shi, Shengyu,Yao, Chenzhi
supporting information, p. 18172 - 18178 (2020/08/21)
Commercial PEG-amine is of unreliable quality, and conventional PEG functionalization relies on esterification and etherification steps, suffering from incomplete conversion, harsh reaction conditions, and functional-group incompatibility. To solve these challenges, we propose an efficient strategy for PEG functionalization with carbamate linkages. By fine-tuning terminal amine basicity, stable and high-fidelity PEG-amine with carbamate linkage was obtained, as seen from the clean MALDI-TOF MS pattern. The carbamate strategy was further applied to the synthesis of high-fidelity multi-functionalized PEG with varying reactive groups. Compared to with an ester linkage, amphiphilic PEG-PS block copolymers bearing carbamate junction linkage exhibits preferential self-assembly tendency into vesicles. Moreover, nanoparticles of the latter demonstrate higher drug loading efficiency, encapsulation stability against enzymatic hydrolysis, and improved in vivo retention at the tumor region.
