The P2X purinergic receptor 7 (P2X7) has an essential role in inflammation, innate immunity, tumor progression, neurodegenerative diseases, and several other diseases, leading subsequently to the development of P2X7 modulators. AZ11645373 is a frequently studied P2X7 antagonist tool compound but always used as a racemic mixture. Racemic AZ11645373 can be separated into its respective enantiomers by chiral chromatography, albeit in small batches, and these were stereochemically intact over two years later, by chiral high-performance liquid chromatography (HPLC) analysis. On a higher scale, significant decomposition is observed during purification. One of the enantiomers was crystallized as a palladium complex, and its (