Quantitative LCMS Analysis of Novel Compounds

WES-1 and WES-2 were synthesized as reported previously [15 (link)]. Compound AW-9a was prepared through the reaction of (E)-3-(3-(dimethylamino)acryloyl)-2H-chromen-2-one [21 (link)] with aniline. The purity of the prepared compounds was greater than 96%, as determined by HPLC analysis. Coumarin (IS) was purchased from Sigma-Aldrich (St. Louis, MO, USA) with claimed purity of >99%. Formic acid (LC/MS grade), methanol, and acetonitrile (HPLC grade) were obtained from Fisher Scientific (Pittsburg, PA, USA). Ultra-pure water was obtained from MilliQ UF-Plus system (Millipore, Bedford, MA, USA); resistivity was maintained at 25 °C with TOC <5 ppb and >18 MΩ·cm⁻¹. Blank human plasma samples were purchased from Sigma-Aldrich (St. Louis, MO, USA).