Application of LC-NMR and HR-NMR to the characterization of biphenyl impurities in the synthetic route development for vestipitant, a novel NK1 antagonist

Vestipitant (1) is a novel NK1 antagonist currently under investigation for the treatment of CNS disorders and emesis The first synthetic step comprised a Grignard synthesis An impurity was identified and initially expected to be a symmetric biphenyl This paper reports the work to synthesise the supposed structure and the spectroscopic analyses (LC-NMR and HR-NMR) to correctly identify the real structure and understand the chemical pathway of the impurity (C) 2010 Elsevier B V All rights reserved