161988-89-2Relevant academic research and scientific papers
Substituted amide phenol compound and its preparation method, pharmaceutical composition and use thereof
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Paragraph 0225; 0230-0233, (2019/07/04)
The invention discloses substituted-amide phenolic compounds, their preparation method, a pharmaceutical composition and an application thereof. The compounds have a structure as shown in the general formula I, wherein Z, L and Q are as defined in the spe
Thermodynamic Programming of Erbium(III) Coordination Complexes for Dual Visible/Near-Infrared Luminescence
Golesorkhi, Bahman,Guénée, Laure,Nozary, Homayoun,Fürstenberg, Alexandre,Suffren, Yan,Eliseeva, Svetlana V.,Petoud, Stéphane,Hauser, Andreas,Piguet, Claude
supporting information, p. 13158 - 13169 (2018/09/11)
Intrigued by the unexpected room-temperature dual visible/near-infrared (NIR) luminescence observed for fast-relaxing erbium complexes embedded in triple-stranded helicates, in this contribution, we explore a series of six tridentate N-donor receptors L4–L9 with variable aromaticities and alkyl substituents to extricate the stereoelectronic features responsible for such scarce optical signatures. Detailed solid-state (X-ray diffraction, differential scanning calorimetry, optical spectroscopy) and solution (speciations and thermodynamic stabilities, spectrophotometry, NMR and optical spectroscopy) studies of mononuclear unsaturated [Er(Lk)2]3+ and saturated triple-helical [Er(Lk)3]3+ model complexes reveal that the stereoelectronic changes induced by the organic ligands affect inter- and intramolecular interactions to such an extent that 1) melting temperatures in solids, 2) the affinity for trivalent erbium in solution, and 3) optical properties in luminescent complexes can be rationally varied and controlled. With this toolkit in hand, mononuclear erbium complexes with low stabilities displaying only NIR emission can be transformed into molecular-based dual Er-centered visible/NIR emitters operating at room temperature in both solid and solution states.
Total synthesis of (+)-trans-trikentrin A
Tébéka, Iris R. M.,Longato, Giovanna B.,Craveiro, Marcus V.,De Carvalho, Jo?o E.,Ruiz, Ana L. T. G.,Silva Jr., Luiz F.
, p. 16890 - 16901 (2013/03/14)
Several syntheses have already been reported for cis-trikentrins and herbindoles, which are indole alkaloids unsubstituted at the C2 and C3 positions that bear a trans-1,3-dimethylcyclopentyl unit. Herein, we describe the first asymmetric and stereoselective synthesis of the more challenging trans-trikentrin A as its naturally occurring isomer. Different approaches were investigated and the strategy of choice was a combination of an enzymatic kinetic resolution and a thallium(III)-mediated ring contraction. The antiproliferative activities of the natural product and related intermediates have been tested against human tumor cell lines, leading to the discovery of new compounds with potent antitumor activity. Simple target? Take a look again! The first stereoselective synthesis of a trans-trikentrin is described (see scheme). In contrast, all cis-related natural products have already been synthesized. An enzymatic kinetic resolution and a ring contraction are the key steps. Potent antitumor compounds have been discovered during this study. Copyright
Asymmetric hydrovinylation of vinylindoles. A facile route to cyclopenta[g]indole natural products (+)-cis-trikentrin A and (+)-cis-trikentrin B
Liu, Wang,Lim, Hwan Jung,Rajanbabu
supporting information; experimental part, p. 5496 - 5499 (2012/05/20)
Vinylindoles undergo Ni(II)-catalyzed asymmetric hydrovinylation under very mild conditions (-78 °C, 1 atm ethylene, 4 mol % catalyst) to give the corresponding 2-but-3-enyl derivatives in excellent yields and enantioselectivities. Hydroboration of the alkene and oxidation to an acid, followed by Friedel-Crafts annulation, gives an indole-annulated cyclopentanone that is a suitable precursor for the syntheses of cis-trikentrins and all known herbindoles. For example, the cyclopentanone from 4-ethyl-7-vinylindole is converted into (+)-cis-trikentin A in four steps (Wittig reaction, alkene isomerization, diastereoselective hydrogenation, and nitrogen deprotection). The previous synthesis of this molecule from (S)-(-)-malic acid involved more than 20 steps and a preparative HPLC separation of diastereomeric intermediates.
A diastereoselective total synthesis of trans-trikentrin A: A ring contraction approach
Silva Jr., Luiz F.,Craveiro, Marcus V.
supporting information; experimental part, p. 5417 - 5420 (2009/06/06)
(Chemical Equation Presented) A new route to obtain the polyalkylated indole (±)-trans-trikentrin A was developed. The synthesis of this natural alkaloid features a thallium(III)-mediated ring contraction reaction to obtain the trans-1,3-disubstituted five-membered ring in a diastereoselective manner. Thallium(III) is chemoselective in this rearrangement, reacting with the olefin without oxidation of the indole moiety. Other key transformations are the Bartoli's reaction to construct the heterocyclic ring and a Heck coupling to add the carbons atom that will originate the nonaromatic cycle.
Total Synthesis of (+/-)-cis-Trikentrin A
Wiedenau, Paul,Monse, Barbara,Blechert, Siegfried
, p. 1167 - 1176 (2007/10/02)
Two patways towards the construction of the trikentrin skeleton are presented, one leading to the total synthesis of (+/-)-cis-Trikentrin A (1).The key step is the intramolecular Heck coupling of the triflate 21 to form the five-membered ring of the indenes 22 and 23.
