(2R)-4-[4-(2-fluoro-4-methoxyphenyl)-2-oxopyridin-1(2H)-yl]-N-hydroxy-2-methyl-2-(methylsulfonyl)butanamide is a potent and selective small-molecule inhibitor of histone deacetylase 6 (HDAC6). It is commonly known as Nexturastat A. This compound features a hydroxamic acid zinc-binding group, a methylsulfonyl linker, and a 2-fluoro-4-methoxyphenyl-substituted pyridone cap group, which confers its high selectivity for HDAC6 over other HDAC isoforms. Nexturastat A is primarily used as a chemical probe in biomedical research to investigate the biological functions of HDAC6 in various cellular processes, including cell motility, protein degradation via aggresome formation, and immune synapse formation. Its HDAC6 inhibitory activity has established it as a valuable tool for studying oncology, neurodegenerative diseases, and inflammation. Due to its mechanism of action and research applications in cancer biology, it is categorized within the domain of oncology drug discovery and targeted protein degradation tools. The compound is supplied for research use only. It is typically handled under standard laboratory safety protocols, as it may have potential effects on cellular pathways.