- Synthetic studies to help elucidate the metabolism of the preclinical candidate TBAJ-876—a less toxic and more potent analogue of bedaquiline
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Bedaquiline is a novel drug approved in 2012 by the FDA for treatment of drug-resistant tuberculosis (TB). Although it shows high efficacy towards drug-resistant forms of TB, its use has been limited by the potential for significant side effects. In particular, bedaquiline is a very lipophilic compound with an associated long terminal half-life and shows potent inhibition of the cardiac potassium hERG channel, resulting in QTc interval prolongation in humans that may result in cardiac arrhythmia. To address these issues, we carried out a drug discovery programme to develop an improved second generation analogue of bedaquiline. From this medicinal chemistry program, a candidate (TBAJ-876) has been selected to undergo further preclinical evaluation. During this evaluation, three major metabolites arising from TBAJ-876 were observed in several preclinical animal models. We report here our synthetic efforts to unequivocally structurally characterize these three metabolites through their independent directed synthesis.
- Choi, Peter J.,Conole, Daniel,Sutherland, Hamish S.,Blaser, Adrian,Tong, Amy S.T.,Cooper, Christopher B.,Upton, Anna M.,Palmer, Brian D.,Denny, William A.
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- 3,5-Dialkoxypyridine analogues of bedaquiline are potent antituberculosis agents with minimal inhibition of the hERG channel
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Bedaquiline is a new drug of the diarylquinoline class that has proven to be clinically effective against drug-resistant tuberculosis, but has a cardiac liability (prolongation of the QT interval) due to its potent inhibition of the cardiac potassium channel protein hERG. Bedaquiline is highly lipophilic and has an extremely long terminal half-life, so has the potential for more-than-desired accumulation in tissues during the relatively long treatment durations required to cure TB. The present work is part of a program that seeks to identify a diarylquinoline that is as potent as bedaquiline against Mycobacterium tuberculosis, with lower lipophilicity, higher clearance, and lower risk for QT prolongation. Previous work led to the identification of compounds with greatly-reduced lipophilicity compounds that retain good anti-tubercular activity in vitro and in mouse models of TB, but has not addressed the hERG blockade. We now present compounds where the C-unit naphthalene is replaced by a 3,5-dialkoxy-4-pyridyl, demonstrate more potent in vitro and in vivo anti-tubercular activity, with greatly attenuated hERG blockade. Two examples of this series are in preclinical development.
- Sutherland, Hamish S.,Tong, Amy S.T.,Choi, Peter J.,Blaser, Adrian,Conole, Daniel,Franzblau, Scott G.,Lotlikar, Manisha U.,Cooper, Christopher B.,Upton, Anna M.,Denny, William A.,Palmer, Brian D.
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supporting information
p. 1292 - 1307
(2019/02/25)
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- ANTIBACTERIAL COMPOUNDS AND USES THEREOF
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The present invention relates to compounds of formula (I) including any stereochemically isomeric form thereof, or pharmaceutically acceptable salts thereof, for the treatment of tuberculosis.
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Paragraph 0111
(2017/09/28)
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- Fluorine-free blue-green emitters for light-emitting electrochemical cells
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There is presently a lack of efficient and stable blue emitters for light-emitting electrochemical cells (LEECs), which limits the development of white light emitting systems for lighting. Cyclometalated iridium complexes as blue emitters tend to show low photoluminescence efficiency due to significant ligand-centred character of the radiative transition. The most common strategy to blue-shift the emission is to use fluorine substituents on the cyclometalating ligand, such as 2,4-difluorophenylpyridine, dFppy, which has been shown to decrease the stability of the emitter in operating devices. Herein we report a series of four new charged cyclometalated iridium complexes using methoxy- and methyl-substituted 2,3′-bipyridine as the main ligands. The combination of donor groups and the use of a cyclometalated pyridine has been recently reported for neutral complexes and found electronically equivalent to dFppy. We describe the photophysical and electrochemical properties of the complexes in solution and use DFT and TDDFT calculations to gain insights into their properties. The complexes exhibit bluish-green emission with onsets around 450 nm, which correspond to the maximum emission at 77 K. Furthermore, photoluminescence quantum yields in solution are all above 40%, with the brightest in the series at 66%. Finally, LEECs were prepared using these complexes as the emissive material to evaluate the performance of this particular design. Compared to previously reported devices with fluorine-containing emitters, the emitted colours are slightly red-shifted due to methyl substituents on the coordinating pyridine of the main ligand and overall device performances, unfortunately including the stability of devices, are similar to those previously reported. Interestingly within the series of complexes there appears to be a positive effect of the methoxy-substituents on the stability of the devices. The poor stability is therefore attributed to the combination of cyclometalated pyridine and methoxy groups. the Partner Organisations 2014.
- Evariste, Sloane,Sandroni, Martina,Rees, Thomas W.,Roldan-Carmona, Cristina,Gil-Escrig, Lidon,Bolink, Henk J.,Baranoff, Etienne,Zysman-Colman, Eli
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p. 5793 - 5804
(2014/07/22)
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- Towards compatibility between ruthenium sensitizers and cobalt electrolytes in dye-sensitized solar cells
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Ruthenium and Co: Ruthenium(II) complexes remain prime candidates for dye-sensitized solar applications; however, current ruthenium sensitizers are not compatible with cobalt(II/III) electrolytes. Herein, the effect of surface insulation on device efficiency is studied by comparing two cyclometalated tris-heteroleptic ruthenium(II) complexes. This approach demonstrates a general principle that leads to unprecedented efficiency for a ruthenium(II) sensitizer used in combination with a cobalt electrolyte. Copyright
- Polander, Lauren E.,Yella, Aswani,Curchod, Basile F. E.,Ashari Astani, Negar,Teuscher, Joel,Scopelliti, Rosario,Gao, Peng,Mathew, Simon,Moser, Jacques-E.,Tavernelli, Ivano,Rothlisberger, Ursula,Graetzel, Michael,Nazeeruddin, Md. Khaja,Frey, Julien
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supporting information
p. 8731 - 8735
(2013/09/12)
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- (Dimethoxy- and dihalopyridyl)boronic acids and highly functionalized heteroarylpyridines by Suzuki cross-coupling reactions
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We report the synthesis of (2,6-dimethoxy-3-pyridyl)boronic acid (2), (2,3-dimethoxy-4-pyridyl)boronic acid (4), (2,6-difluoro-3-pyridyl)boronic acid (6), (2,6-dichloro-3-pyridyl)-boronic acid (8) and (2,3-dichloro-4-pyridyl) boronic acid (10) by directed ortho-metalation reactions on the corresponding disubstituted pyridine precursor, followed by the reaction with triisopropyl borate (TPB) or trimethyl borate. The reactivity of the pyridylboronic acids with heteroaryl halides in Suzuki-Miyaura cross-coupling reactions has been evaluated. New highly functionalized heteroarylpyridine derivatives have thereby been obtained in moderate to high yields. The reaction of 8 and 3-amino-2-chloropyridine yielded the rare 5H-pyrrolo[2,3-b:4,5-b′] dipyridine (i.e. 1,5-diazacarbazole) ring system by sequential cross-coupling and intramolecular cyclisation reactions. The X-ray crystal structures are reported for the pyridylboronic acids 2, 4, 8 and 10. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Smith, Amy E.,Clapham, Kate M.,Batsanov, Andrei S.,Bryce, Martin R.,Tarbit, Brian
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experimental part
p. 1458 - 1463
(2009/04/04)
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