Process Research on a Phenoxybutyric Acid LTB4 Receptor Antagonist. Efficient Kilogram-Scale Synthesis of a 3,5-Bisarylphenol Core

An improved, kilogram-scale synthesis of a LTB4 receptor antagonist is reported. The title compound was prepared in four linear steps (seven steps total) and 54% overall yield. The 3,5-bisarylphenol core was obtained in nearly quantitative yield by the condensation of 1-benzotriazol-1-ylpropan-2-one with a chalcone. Although all the intermediates were oils, no chromatography purification was required.