Crystal structure of nafamostat dimesylate

Nafamostat dimesylate {systematic name: [amino({6-[(4-{[amino(iminiumyl)methyl]amino}phenyl)carbonyloxy]naphthalen-2-yl})methylidene]azanium bis(methanesulfonate)}, C₁₉H₁₉N₅O₂ ²⁺·2CH₃O₃S^-, is a broad-spectrum serine protease inhibitor and has been applied clinically as an anti-coagulant agent during hemodialysis and for treatment of severe acute pancreatitis (SAP). Since nafamostat contains flexible moieties, it is necessary to determine the conformation to understand the structure-activity relationships. The divalent cation has a screw-like motif. The guanidinium group is approximately perpendicular to the naphthyl ring system, subtending a dihedral angle of 84.30 (14)°. In the crystal, the nafamostat mol-ecules form columnar structures surrounded by a hydro-philic region.