Crystal Structures of Pyridine Sulfonamides and Sulfonic Acids

Despite the widespread occurrence of pyridinesulfonic
acid and pyridinesulfonamide functional groups in drugs and pharmaceuticals,
and their use as ligands in metal–organic frameworks, a systematic
structural study of their hydrogen bonding and molecular packing is
lacking. We discuss crystal structures of 2-, 3-, and 4-pyridinesulfonic
acids/amides in terms of N+–H···O– hydrogen bonds, N–H···O dimer/catemer
synthons, and graph set notations. This model study provides a background
for polymorph screening and solid form hunting of pharmacologically
active sulfonamides.