Mefloquine derivatives: Crystal structures and anti-tubercular activities of diphenyl[((R,S)-2,8-bis(trifluoromethyl)quinolin-4-yl)-piperidin-2-yl-methanolato-O,N]boron and (±)-erythro-mefloquinium tetraphenylborate solvates

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Abstract

Thermolysis of (R^*,S^*)-(2-{[2,8-bis(trifluoromethyl)quinolin-4-yl](hydroxy)∼methyl}piperidin-1-ium) tetraphenylborate, (±)-erythro-mefloquinium tetraphenylborate, 3, in solution or neat, provides the oxazaborolidine derivative, diphenyl[(R^*,S^*)-(2,8-bis(trifluoromethyl)quinolin-4-yl)]piperidin-2-yl-methanolato-O,N]boron, 2. Crystal structures of solvates of 2 and 3 are reported. As shown by the ¹H NMR spectrum, 2 undergoes a conformation equilibrium in solution. Both 2 and 3 exhibit important anti-tubercular activities as indicated by the minimum inhibitory concentrations (MIC) of 50 and 12.5 μg/ml, respectively, in in vitro assays against M. tuberculosis H37Rv ATTC 27294.

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Keywords: Tuberculosis; Mefloquine derivatives; Crystal structures; Boron compounds; oxazaborolidine Document Type: Research Article DOI: http://dx.doi.org/10.1016/j.molstruc.2011.01.019 Publication date: 29 de Março de 2011