Efficient Synthesis of Impurity-C of Antimigraine Agent Rizatriptan Benzoate

During the commercial manufacturing of antimigraine drug Rizatriptan benzoate, several impurities are reported to be formed. This present work demonstrates a convergent and short synthesis of the most critical impurity (C) of Rizatriptan, [2-(5-((1H-1,2,4-triazol-1-yl)­methyl)-1H-indole-2-yl)-<i>N</i>,<i>N</i>-dimethylethanamine (<b>1</b>)], recently reported in U.S. Pharmacopeia