An Efficient Synthesis of Ivacaftor

Abstract

New and practical synthetic route of ivacaftor is described on a grams scale. An electrophilic addition of two t-butyl groups to the aromatic ring is adopted to prepare 5-amino-2,4-di-t-butylphenol in 61% yield over three steps with 98.1% purity (high-performance liquid chromatography). An intramolecular cyclization of ethyl 3-(2-aminophenyl)-3-oxo-propanoate with dimethylformamide-dynamic mechanical analysis is used to prepare 4-oxo-1,4-dihydroquinoline-3-carboxylic acid in 54% yield over four steps. Ivacaftor is obtained by condensation of the two parts in 71% yield with 99.1% purity (high-performance liquid chromatography).