Synthesis and structure of azelastine-N-oxides

Abstract

Azelastine is among the most frequently used drugs; however, knowledge and solid data about its metabolites are scarcely found in literature. Thus, microsomal oxidation of azelastine is thought to produce the corresponding N-oxides, However, until now these products had never been produced in significant amounts. By oxidation of azelastine with H2O2, these N-oxides were now prepared in racemic form for the first time and were fully characterized. Their structure was additionally confirmed by a single crystal X-ray analysis. Both N-oxides were found to be non-cytotoxic in SRB assays.