Comparison of (bio-)transformation methods for the generation of metabolite-like compound libraries of p38α MAP kinase inhibitors using high-resolution screening.

•p38α MAP kinase inhibitors were modified by hydrogen peroxide or visible light.•Integrated approach for modification, separation, structure and bioaffinity.•Comparison of methods for generation of metabolite-like lead libraries.•Many bioactive, mostly more hydrophilic conversion products were yielded.•High-resolution screening excellent approach for library assessment and initial SAR.