- Fe(PyTACN)-catalyzed cis-dihydroxylation of olefins with hydrogen peroxide
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A family of iron complexes with general formula [Fe(II)( R,Y,XPyTACN)(CF3SO3)2], where R,Y,XPyTACN=1-[2′-(4-Y-6-X-pyridyl)methyl]-4,7-dialkyl-1,4, 7-triazacyclononane, X and Y refer to the groups at positions 4 and 6 of the pyridine, respectively, and R refers to the alkyl substitution at N-4 and N-7 of the triazacyclononane ring, are shown to be catalysts for efficient and selective alkene oxidation (epoxidation and cis-dihydroxylation) employing hydrogen peroxide as oxidant. Complex [Fe(II)(Me,Me,HPyTACN)(CF 3SO3)2] (7), was identified as the most efficient and selective cis-dihydroxylation catalyst among the family. The high activity of 7 allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and under conditions where the olefin is not used in large amounts but instead is the limiting reagent. In the presence of 3 mol% of 7, 2 equiv. of H2O2 as oxidant and 15 equiv. of water, in acetonitrile solution, alkenes are cis-dihydroxylated reaching yields that might be interesting for synthetic purposes. Competition experiments show that 7 exhibits preferential selectivity towards the oxidation of cis olefins over the trans analogues, and also affords better yields and high [syn-diol]/[epoxide] ratios when cis olefins are oxidized. For aliphatic substrates, reaction yields attained with the present system compare favourably with state of the art Fe-catalyzed cis-dihydroxylation systems, and it can be regarded as an attractive complement to the iron and manganese systems described recently and which show optimum activity against electron-deficient and aromatic olefins. Copyright
- Prat, Irene,Font, David,Company, Anna,Junge, Kathrin,Ribas, Xavi,Beller, Matthias,Costas, Miquel
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p. 947 - 956
(2013/05/08)
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- 5-lipoxygenase-activating protein (FLAP) inhibitors. Part 4: Development of 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxypyridin-3-yl)benzyl]-5-(5-methylpyridin- 2-ylmethoxy)-1 H -indol-2-yl]-2,2-dimethylpropionic acid (AM803), a potent, oral, once daily FLAP inhibitor
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The potent 5-lipoxygenase-activating protein (FLAP) inhibitor 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxypyridin-3-yl)benzyl]-5-(5-methylpyridin-2- ylmethoxy)-1H-indol-2-yl]-2,2-dimethylpropionic acid 11cc is described (AM803, now GSK2190915). Building upon AM103 (1) (Hutchinson et al. J. Med Chem.2009, 52, 5803-5815; Stock et al. Bioorg. Med. Chem. Lett. 2010, 20, 213-217; Stock et al. Bioorg. Med. Chem. Lett.2010, 20, 4598-4601), SAR studies centering around the pyridine moiety led to the discovery of compounds that exhibit significantly increased potency in a human whole blood assay measuring LTB4 inhibition with longer drug preincubation times (15 min vs 5 h). Further studies identified 11cc with a potency of 2.9 nM in FLAP binding, an IC50 of 76 nM for inhibition of LTB4 in human blood (5 h incubation) and excellent preclinical toxicology and pharmacokinetics in rat and dog. 11cc also demonstrated an extended pharmacodynamic effect in a rodent bronchoalveolar lavage (BAL) model. This compound has successfully completed phase 1 clinical studies in healthy volunteers and is currently undergoing phase 2 trials in asthmatic patients.
- Stock, Nicholas S.,Bain, Gretchen,Zunic, Jasmine,Li, Yiwei,Ziff, Jeannie,Roppe, Jeffrey,Santini, Angelina,Darlington, Janice,Prodanovich, Pat,King, Christopher D.,Baccei, Christopher,Lee, Catherine,Rong, Haojing,Chapman, Charles,Broadhead, Alex,Lorrain, Dan,Correa, Lucia,Hutchinson, John H.,Evans, Jilly F.,Prasit, Peppi
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p. 8013 - 8029
(2012/03/08)
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