O. Peeters, N. Blaton, C. J. Ranter
Apr 15, 1994
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Journal
Acta Crystallographica Section C-crystal Structure Communications
Abstract
X-ray diffraction study of the title compounds (4- carboxy-3-methyl-4-phenylpiperidinium bromide, C13- HIsNO~.Br-) showed that the absolute configurations of (I) and (II) are (3S,4R) and (3S,4S), respectively. In both structures the phenyl group is equatorial and the carboxyl group is axial. In (I) the methyl group is in an axial posi- tion while in (H) it is in an equatorial position. Comment benzyl ester of 3-methyl-4-phenyl-4-piperidinecar- boxylic acid is an intermediate in the synthesis of 1-(4- cyano-4-(4-fluorophenyl) cyclohexyl)-3-methyl-4-phen- yl-4-piperidinecarboxylic acid (Levocabastine, Janssen Research Foundation internal code R50547), the proto- type of a chemical series of compounds with specific Hi- antihistaminic activity. The geometry of the four possible racemates of the latter compound could be derived from the NMR spectra of their benzyl esters (Stokbroeckx et al., 1986). In order to confirm the geometries of the piperi- dine moieties and obtain their absolute configurations, X- ray structure determinations of the title compounds were undertaken. H