1984-23-2Relevant academic research and scientific papers
Molybdenum-Catalyzed Stannylations as Key Steps in Heterocyclic Synthesis
Braune, Sascha,Pohlman, Matthias,Kazmaier, Uli
, p. 468 - 474 (2004)
THF/carbonyl complexes of molybdenum and tungsten are suitable precursors for the synthesis of the corresponding monoisonitrile carbonyl complexes. Whereas complexes with electron-rich isonitriles are suitable for regioselective hydrostannations, complexe
Small molecule microarray identifies inhibitors of tyrosyl-DNA phosphodiesterase 1 that simultaneously access the catalytic pocket and two substrate binding sites
Zhao, Xue Zhi,Kiselev, Evgeny,Lountos, George T.,Wang, Wenjie,Tropea, Joseph E.,Needle, Danielle,Hilimire, Thomas A.,Schneekloth, John S.,Waugh, David S.,Pommier, Yves,Burke, Terrence R.
, p. 3876 - 3884 (2021/04/02)
Tyrosyl-DNA phosphodiesterase 1 (TDP1) is a member of the phospholipase D family of enzymes, which catalyzes the removal of both 3′- and 5′-DNA phosphodiester adducts. Importantly, it is capable of reducing the anticancer effects of type I topoisomerase (TOP1) inhibitors by repairing the stalled covalent complexes of TOP1 with DNA. It achieves this by promoting the hydrolysis of the phosphodiester bond between the Y723 residue of human TOP1 and the 3′-phosphate of its DNA substrate. Blocking TDP1 function is an attractive means of enhancing the efficacy of TOP1 inhibitors and overcoming drug resistance. Previously, we reported the use of an X-ray crystallographic screen of more than 600 fragments to identify small molecule variations on phthalic acid and hydroxyquinoline motifs that bind within the TDP1 catalytic pocket. Yet, the majority of these compounds showed limited (millimolar) TDP1 inhibitory potencies. We now report examining a 21?000-member library of drug-like Small Molecules in Microarray (SMM) format for their ability to bind Alexa Fluor 647 (AF647)-labeled TDP1. The screen identified structurally similarN,2-diphenylimidazo[1,2-a]pyrazin-3-amines as TDP1 binders and catalytic inhibitors. We then explored the core heterocycle skeleton using one-pot Groebke-Blackburn-Bienayme multicomponent reactions and arrived at analogs having higher inhibitory potencies. Solving TDP1 co-crystal structures of a subset of compounds showed their binding at the TDP1 catalytic site, while mimicking substrate interactions. Although our original fragment screen differed significantly from the current microarray protocol, both methods identified ligand-protein interactions containing highly similar elements. Importantly inhibitors identified through the SMM approach show competitive inhibition against TDP1 and access the catalytic phosphate-binding pocket, while simultaneously providing extensions into both the substrate DNA and peptide-binding channels. As such, they represent a platform for further elaboration of trivalent ligands, that could serve as a new genre of potent TDP1 inhibitors.
Silver-Catalyzed Selective Multicomponent Coupling Reactions of Arynes with Nitriles and Isonitriles
Ghorai, Sourav,Lin, Yongjia,Xia, Yuanzhi,Wink, Donald J.,Lee, Daesung
, p. 642 - 647 (2020/01/31)
Pathway selective aryne-based novel multicomponent coupling reactions with isonitriles and nitriles are described. Crucial to these reactions is the formation of a silver-aryne complex, which shows differential reactivity toward isonitriles and nitriles to form two different forms of ortho-nitrilium organosilver arene species. Interception of the nitrilium of an aryne-isonitrile adduct with another isonitrile leads to the formation of benzocyclobutene-1,2-diimines, whereas the nitrilium of an aryne-nitrile adduct renders selective formation of 3H-indol-3-imines or 3-iminoindolin-2-ol depending on the structure of the nitrile employed.
Mild C?F Activation in Perfluorinated Arenes through Photosensitized Insertion of Isonitriles at 350 nm
Weidlich, Frauke,Esumi, Naoto,Chen, Dongyang,Mück-Lichtenfeld, Christian,Zysman-Colman, Eli,Studer, Armido
, p. 376 - 383 (2019/11/19)
Fluorinated compounds have become important in the fields of agrochemical industry, pharmaceutical chemistry and materials sciences. Accordingly, various methods for their preparation have been developed in the past. Fluorinated compounds can be accessed via conjugation with fluorinated building blocks, via C?H fluorination or via selective activation of perfluorinated compounds to give the partially fluorinated congeners. Especially the direct activation of C?F bonds, one of the strongest σ-bonds, still remains challenging and new strategies for C?F activation are desirable. Herein a method for the photochemical activation of aromatic C?F bonds is presented. It is shown that isonitriles selectively insert into aromatic C?F bonds while aliphatic C?F bonds remain unaffected. Mechanistic studies reveal the reaction to proceed via the indirect excitation of the isonitrile to its triplet state by photoexcited acetophenone at 350 nm. Due to the relatively mild light used, the process shows high functional group tolerance and various compounds of the class of benzimidoyl fluorides are accessible from aryl isonitriles and commercially available perfluorinated arenes. (Figure presented.).
Design, synthesis and biological evaluation of novel α-acyloxy carboxamides via Passerini reaction as caspase 3/7 activators
Salah Ayoup, Mohammed,Wahby, Yasmin,Abdel-Hamid, Hamida,Ramadan, El Sayed,Teleb, Mohamed,Abu-Serie, Marwa M.,Noby, Ahmed
, p. 340 - 356 (2019/03/04)
Evasion of apoptosis is a hallmark of cancer. Caspases; the key executors of apoptotic cascade are attractive targets for selective induction of apoptosis in cancer cells. Within this approach, various caspase activators were introduced as lead anticancer agents. In the current study, a new series of multifunctional Passerini products was synthesized and evaluated as potent caspase-dependent apoptotic inducers. The synthetic strategy adopted this isocyanide-based multicomponent reaction to possibly mimic the pharmacophoric features of various lead apoptotic inducers, where a series of α-acyloxy carboxamides was prepared from p-nitrophenyl isonitrile, cyclohexanone and various carboxylic acids. Accordingly, the main amide-based scaffold was decorated by substituents with varying nature and size to gain more information about structure-activity relationship. All the synthesized compounds were screened for cytotoxicity against normal human fibroblasts and their potential anticancer activities against three human cancer cell lines; MCF-7 (breast), NFS-60 (myeloid leukemia), and HepG-2 (liver) utilizing MTT assay. Among the most active compounds, 13, 21 and 22 were more potent and safer than doxorubicin with nanomolar IC50 values and promising selectivity indices. Mechanistically, 13, 21 and 22 induced apoptosis by significant caspase activation in all the screened cancer cell lines utilizing flow cytometric analysis and caspase 3/7 activation assay. Again, 13 and 21 recorded higher activation percentages than doxorubicin, while 22 showed comparable results. Apoptosis-inducing factor1 (AIF1) quantification assay declared that 13, 21 and 22 didn't mediate apoptosis through AIF1-dependent pathway (i.e. only by caspase activation). Physicochemical properties, pharmacokinetic profiles, ligand efficiency metrics and drug-likeness data of all the synthesized compounds were computationally predicted and showed that 13, 21 and 22 could be considered as drug-like candidates. Finally, selected compounds were preliminarily screened for possible antimicrobial activities searching for dual anticancer/antimicrobial agents as an advantageous approach for cancer therapy.
Palladium-Catalyzed Diarylation of Isocyanides with Tetraarylleads for the Selective Synthesis of Imines and α-Diimines
Tran, Cong Chi,Kawaguchi, Shin-Ichi,Kobiki, Yohsuke,Matsubara, Hitomi,Tran, Dat Phuc,Kodama, Shintaro,Nomoto, Akihiro,Ogawa, Akiya
, p. 11741 - 11751 (2019/10/02)
Using tetraaryllead compounds (PbAr4) as arylating reagents, isocyanides undergo selective diarylation in the presence of palladium catalysts such as Pd(OAc)2 or Pd(PPh3)4 to afford imines and/or α-diimines based on the isocyanide employed. With aliphatic isocyanides, imines are obtained preferentially, whereas α-diimines are formed in the case of electron-rich aromatic isocyanides. The differences in imine/α-diimine selectivity can be attributed to the stability of imidoylpalladium intermediates formed in this catalytic reaction. Compared with other arylating reagents, tetraaryllead compounds are excellent candidates for use in the selective transformations to imines and/or α-diimines, especially in terms of inhibiting the oligomerization of isocyanides, which results in a lower product selectivity in many transition-metal-catalyzed reactions of isocyanides.
Synthesis of Imides, Imidates, Amidines, and Amides by Intercepting the Aryne-Isocyanide Adduct with Weak Nucleophiles
Ghorai, Sourav,Lee, Daesung
, p. 7390 - 7393 (2019/10/02)
New aryne-based multicomponent coupling reactions for the formation of functionalized aromatic compounds have been developed. Arynes generated from triynes or tetraynes through the hexadehydro Diels-Alder reaction readily react with isocyanide to generate nitrilium intermediate. Intercepting this nitrilium species with various weak nucleophile including carboxylic acids, alcohols, sulfonamides, or water generated the corresponding imides, imidates, amidines, or amides. The high regioselectivity of these transformations was mainly controlled by the substituents of the arynes.
Selective Gold-Catalysed Synthesis of Cyanamides and 1-Substituted 1H-Tetrazol-5-Amines from Isocyanides
?koch, Karel,Císa?ová, Ivana,?těpni?ka, Petr
, p. 13788 - 13791 (2018/09/14)
The newly discovered gold-catalysed reaction of isocyanides with hydrazoic acid generated in situ from trimethylsilyl azide and methanol (or, alternatively, from NaN3/AcOH) produces either cyanamides or 1-substituted 1H-tetrazol-5-amines, depending on the amount of available HN3. The reaction proceeds selectively and in generally high yields of either product, thus providing a particularly convenient access to a wide range of substituted 1H-tetrazol-5-amines that are rather difficult to access otherwise.
One-step synthesis of N, N′-substituted 4-imidazolidinones by an isocyanide-based pseudo-five-multicomponent reaction
Attorresi, Cecilia I.,Bonifazi, Evelyn L.,Ramírez, Javier A.,Gola, Gabriel F.
, p. 8944 - 8949 (2018/12/10)
A pseudo-five-multicomponent reaction involving an isocyanide, a primary amine, two molecules of formaldehyde and water is reported, which gives N,N′-substituted 4-imidazolidinones when trifluoroethanol is used as the solvent. The reaction proceeds with good yields and with a wide variety of amines and isocyanides, providing an efficient new entry to these heterocycles. A preliminary study of the reaction mechanism suggests that trifluoroethanol, although acting as the solvent, is directly involved as a reagent in the reaction pathway.
TEMPO-Catalyzed Aerobic Oxidative Selenium Insertion Reaction: Synthesis of 3-Selenylindole Derivatives by Multicomponent Reaction of Isocyanides, Selenium Powder, Amines, and Indoles under Transition-Metal-Free Conditions
Liu, Huan,Fang, Yi,Wang, Shun-Yi,Ji, Shun-Jun
supporting information, p. 930 - 933 (2018/02/22)
A novel and efficient approach for the selenium functionalization of indoles was developed with selenium powder as the selenium source, catalyzed by 2,2,6,6-tetramethylpiperidinooxy (TEMPO) and employing O2 as the green oxidant. This protocol provides a practical route for the synthesis of 3-selenylindole derivatives and has the advantages of readily available starting materials, mild reaction conditions, and a wide scope of substrates. Electron spin-resonance (ESR) studies reveal that the approach involves the formation of nitrogen-centered radicals and selenium radicals via oxidation of in situ generated selenoates.
