Novel inhibitors of histone deacetylase (hdac), and methods, compositions and uses related thereto

The invention relates to the field of medicinal chemistry and pharmacology, specifically to novel inhibitors of histone deacetylase (HDAC), and to compositions, methods of making, and using them, for instance in the treatment of chronic obstructive pulmonary disease (COPD). Provided is a compound of the formula A or a pharmaceutically acceptable salt, hydrate, or solvate thereof, wherein A is H or an in vivo hydrolysable group, and L is a linker group.