title: The imide tautomer of sulfasalazine.
abstract: The title compound, 5-[4-[(2-pyridylideneamino)sulfonyl]phenyldiazenyl]salicylic acid, C(18)H(14)N(4)O(5)S, crystallizes as the imide tautomer in the monoclinic space group P2(1)/c. In addition to an intramolecular O-H.O hydrogen bond, intermolecular O-H.O interactions link adjacent molecules into helices, which are connected by pairwise N-H.N interactions into two-dimensional hydrogen-bonded layers. Both the molecular conformation and the packing differ from those seen in the triclinic amide form [Filip et al. (2001). Acta Cryst. C57, 435-436].
authors.affiliation: School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, England. a.j.blake@nottingham.ac.uk
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Blake
authors.forename: Xiang
authors.initials: X
authors.lastname: Lin
authors.forename: Martin
authors.initials: M
authors.lastname: Schröder
authors.forename: Claire
authors.initials: C
authors.lastname: Wilson
authors.forename: Rong Xin
authors.initials: RX
authors.lastname: Yuan
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D018360:Crystallography, X-Ray; D007094:Imides / Q000737:chemistry*; D015394:Molecular Structure; D012460:Sulfasalazine / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D007094:Imides; D012460:Sulfasalazine