33588-64-6Relevant academic research and scientific papers
Tandem reorganisation of 1,3-dipolar cycloadducts of C-(4-oxo- 4H[1]benzopyran-3-yl)-N-phenylnitrone and allenic esters, leading to novel functionalized benzo[b]indolizines
Ishar,Kumar, Kamal
, p. 175 - 176 (1999)
C-(4-oxo-4H[1]benzopyran-3-yl)-N-phenylnitrone (1) adds regiospecifically to the C2-C3 π-bond of allenic esters (2a-c) and the 1,3-dipolar cycloadducts formed undergo a series of intramolecular reorganisations including an intramolecular (4+2) cycloaddition, in situ, to yield novel functionalized benzo[b]indolizines (3a-c) in good yields.
Exploring of indole derivatives for ESIPT emission: A new ESIPT-based fluorescence skeleton and TD-DFT calculations
Ayd?n, Hatice Gülten,Ekmekci, Zeynep,Kaya, Serdal,Keskin, Selbi,Menges, Nurettin
, (2021/08/23)
Appropriate synthesis methods gave six different indole derivatives substituted at the C-2 or C-3 position. ESIPT emission capacities of these derivatives were investigated. It was concluded that the indole derivative containing the 1,2-dicarbonyl group at the C-2 position has ESIPT emission. Although adding water to the DMSO solution of the ESIPT-based molecule (9:1) resulted in ESIPT quenching, steady-state measurements in MeOH did not occur ESIPT quenching. TD-DFT calculation for uncovering the ESIPT mechanism emerged that the ESIPT mechanism occurred as a barrierless process. The X-ray analysis and DFT conformational analysis revealed that NH and CO groups involving proton transfer mechanisms are in the cis position. A mono-exponential decay was observed in DMSO and MeOH solutions, in which lifetimes were measured as 6.1 and 5.5 ns, respectively. pH studies revealed that acidic and basic solutions of molecule 7 did not influence ESIPT emission.
Enantioselective Syntheses of Strychnos and Chelidonium Alkaloids through Regio- and Stereocontrolled Cooperative Catalysis
Fyfe, James W. B.,Hutchings-Goetz, Luke S.,Snaddon, Thomas N.,Yang, Chao
supporting information, p. 17556 - 17564 (2020/08/14)
We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α-alkylation. This provides products containing indole-bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent of the N-substituent. This led to concise syntheses of (?)-akuammicine and (?)-strychnine. In the second case, the poor performance of ortho-substituted cinnamyl electrophiles in the enantioselective cooperative isothiourea/Ir catalyzed α-alkylation was overcome by appropriate substituent choice, leading to enantioselective syntheses of (+)-chelidonine, (+)-norchelidonine, and (+)-chelamine.
Synthesis and SAR of Tetracyclic Inhibitors of Protein Kinase CK2 Derived from Furocarbazole W16
Borgert, Sebastian,Daniliuc, Constantin G.,Ensan, Deeba,Jose, Joachim,Kr?ger, Lukas,Lauwers, Miriam,Nienberg, Christian,Pietsch, Markus,Steinkrüger, Michaela,Wünsch, Bernhard
supporting information, p. 871 - 881 (2020/05/06)
The serine/threonine kinase CK2 modulates the activity of more than 300 proteins and thus plays a crucial role in various physiological and pathophysiological processes including neurodegenerative disorders of the central nervous system and cancer. The enzymatic activity of CK2 is controlled by the equilibrium between the heterotetrameric holoenzyme CK2α2β2 and its monomeric subunits CK2α and CK2β. A series of analogues of W16 ((3aR,4S,10S,10aS)-4-{[(S)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-10-(3,4,5-trimethoxyphenyl)-4,5,10,10a-tetrahydrofuro[3,4-b]carbazole-1,3(3aH)-dione ((+)-3 a)) was prepared in an one-pot, three-component Levy reaction. The stereochemistry of the tetracyclic compounds was analyzed. Additionally, the chemically labile anhydride structure of the furocarbazoles 3 was replaced by a more stable imide (9) and N-methylimide (10) substructure. The enantiomer (?)-3 a (Ki=4.9 μM) of the lead compound (+)-3 a (Ki=31 μM) showed a more than sixfold increased inhibition of the CK2α/CK2β interaction (protein-protein interaction inhibition, PPII) in a microscale thermophoresis (MST) assay. However, (?)-3 a did not show an increased enzyme inhibition of the CK2α2β2 holoenzyme, the CK2α subunit or the mutated CK2α′ C336S subunit in the capillary electrophoresis assay. In the pyrrolocarbazole series, the imide (?)-9 a (Ki=3.6 μM) and the N-methylimide (+)-10 a (Ki=2.8 μM) represent the most promising inhibitors of the CK2α/CK2β interaction. However, neither compound could inhibit enzymatic activity. Unexpectedly, the racemic tetracyclic pyrrolocarbazole (±)-12, with a carboxy moiety in the 4-position, displays the highest CK2α/CK2β interaction inhibition (Ki=1.8 μM) of this series of compounds.
Involving Single-Atom Silver(0) in Selective Dehalogenation by AgF under Visible-Light Irradiation
Wu, Wenli,Cui, Enxin,Zhang, Yun,Zhang, Chen,Zhu, Feng,Tung, Chen-Ho,Wang, Yifeng
, p. 6335 - 6341 (2019/07/04)
The dehalogenation-arylation and the hydrodehalogenation of various types of organic halides are selectively realized using AgF and visible light without any organic additives under mild conditions. Single-atom silver(0) (denoted as SAAg) serves as the catalytically active center, and the TOF of SAAg reaches 6000 h-1. This elusive activity of Ag is beyond that expected from its ionic, nano, or bulk forms.
Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters
Ciszewski, Lukasz W.,Durka, Jakub,Gryko, Dorota
supporting information, p. 7028 - 7032 (2019/09/12)
This article describes the photoalkylation of electron-rich aromatic compounds with diazo esters. C-2-alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst loading is as low as 0.075 mol %. For EWG-substituted substrates, the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG- and EWG-EDG-substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway.
Versatile synthesis of functionalized β- And γ-carbolines: Via Pd-catalyzed C-H addition to nitriles/cyclization sequences
Wang, Ting-Ting,Zhang, Di,Liao, Wei-Wei
supporting information, p. 2048 - 2051 (2018/03/01)
The first example of versatile synthesis of functionalized β-carbolines and γ-carbolines via redox-free Pd-catalyzed C-H addition of indole to nitrile/cyclization sequences is reported. A wide range of functionalized β-carbolines and γ-carbolines can be prepared from readily accessible indoles and nitriles in good to excellent yields under the optimal conditions.
Visible light/Ir(III) photocatalytic initiation of xanthate-based radical-chain reactions: Xanthate group transfer and oxidative addition to aromatic systems
López-Mendoza, Pedro,Díaz, John E.,Loaiza, Alix E.,Miranda, Luis D.
supporting information, p. 5494 - 5502 (2018/05/16)
A photocatalyzed redox generation of radicals from O-ethyl xanthates to generate electrophilic radicals under photoredox catalysis, using Ir(ppy)3 and blue LEDs irradiation is described. The protocol can be used in classical xanthate-based inter- and intra-molecular group transfer reactions and oxidative radical addition to several heteroaromatic systems. The process does not require high temperature and reactions are cleaner compared with the traditional peroxide initiation. In the oxidative addition to aromatic systems, the oxidation process is part of the catalytic cycle and does not require a stoichiometric oxidant such as DLP which is particularly difficult to separate from the product.
Environmentally Friendly Synthesis of Indoline Derivatives using Flow-Chemistry Techniques
?rkényi, Róbert,Beke, Gyula,Riethmüller, Eszter,Szakács, Zoltán,Kóti, János,Faigl, Ferenc,éles, János,Greiner, István
supporting information, p. 6525 - 6532 (2017/12/02)
Flow chemistry proved to be a valuable technique to improve the synthesis route to melanin-concentrating hormone receptor 1 (MCHr1) antagonists with the 1H,2H,3H,4H,5H-[1,4]diazepino[1,7-a]indole scaffold. A one-step route for the heterogeneous catalytic hydrogenation of ethyl 4-(2-nitrophenyl)-3-oxobutanoate for the synthesis of ethyl 2-(2,3-dihydro-1H-indol-2-yl)acetate was developed, and the use of common reducing chemicals was avoided. N-Alkylation of the indoline nitrogen atom was also optimized by using a purpose-built flow reactor and by design of experiment (DoE). Applying an optimal set of parameters allowed us to decrease the amount of carcinogenic 1,2-dibromoethane used by a factor of 10. Additionally, nearly complete conversion was achieved in a fraction of the original reaction time (30 min vs. 4 d); therefore, the productivity (space-time yield) of the flow-reactor system was proven to be ca. 200 times higher than that of the batch process.
Palladium-Catalyzed Dearomatizing Difunctionalization of Indoles and Benzofurans
Ramella, Vincenzo,He, Zhiheng,Daniliuc, Constantin G.,Studer, Armido
supporting information, p. 2268 - 2273 (2016/05/19)
A palladium-catalyzed dearomatizing difunctionalization of N-Boc-indoles and benzofurans to give tricyclic indolines and 2,3-dihydrobenzofurans with a fully substituted carbon center is described. Product formation occurs under mild conditions at room temperature with commercially available aryl boronic acids and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a mild oxidant in good yields. 2-Carboxyalkyl-substituted indoles and benzofurans react under Pd-catalysis with aryl boronic acids and TEMPO through dearomatizing arylation/cyclization to the corresponding indolines and dihydrobenzofurans containing a lactone moiety bearing a fully substituted carbon center.
