This compound is a key impurity that occurs during the synthesis of ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor used to treat hematological malignancies such as chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). Used primarily as a reference standard in pharmaceutical quality control and analytical testing during ibrutinib production, it helps ensure the purity and consistency of the final drug product. It is instrumental in validating analytical methods, such as HPLC and mass spectrometry (including LC-MS), to detect and quantify impurities in ibrutinib formulations. Due to its structural similarity to the active pharmaceutical ingredient, it aids in studying degradation pathways and establishing stability profiles of ibrutinib under various storage conditions. Controlled levels of this impurity support compliance with regulatory guidelines for drug safety and efficacy.