Synthesis, crystal structure and Hirshfeld surface analysis of sulfamethoxazolium methylsulfate monohydrate.

The mol­ecular salt sulfamethoxazolium {or 4-[(5-methyl-1,2-oxazol-3-yl)sulf­amo­yl]anilinium methyl sulfate monohydrate}, C₁₀H₁₂N₃O₃S+·CH₃O₄S-·H₂O, was prepared by the reaction of sulfamethoxazole and H₂SO₄ in methanol and crystallized from methanol-ether-water. Protonation takes place at the nitro­gen atom of the primary amino group. In the crystal, N--H⋯O hydrogen bonds (water and methyl­sulfate anion) and inter­molecular N--H⋯N inter­actions involving the sulfonamide and isoxazole nitro­gen atoms, link the components into a tri-dimensional network, additional cohesion being provided by face-to-face π-π inter­actions between the phenyl rings of adjacent mol­ecules. A Hirshfeld surface analysis was used to verify the contributions of the different inter­molecular inter­actions, showing that the three most important contributions for the crystal packing are from H⋯O (54.1%), H⋯H (29.2%) and H⋯N (5.0%) inter­actions. [ABSTRACT FROM AUTHOR]