38383-27-6Relevant articles and documents
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 (2012)
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
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.
