title: An infrared study of tautomerism in acetohexamide polymorphs.
abstract: Infrared data determined for known polymorphic forms and some new derivatives of acetohexamide and related compounds support the view that acetohexamide polymorphs exhibit keto-enol tautomerism. They indicate that type A polymorphs exist in the enol form, probably stabilized by intramolecular bonding between an O-H and S = O group to form a six-membered ring. Type B polymorphs exist in the keto form with the urea carbonyl group intermolecularly bonded to a sulphonamide N-H. The new evidence disputes previous interpretations of the data.
authors.affiliation: Welsh School of Pharmacy, University of Wales College of Cardiff, UK.
authors.forename: P G
authors.initials: PG
authors.lastname: Takla
authors.forename: C J
authors.initials: CJ
authors.lastname: Dakas
mesh_terms: D000092:Acetohexamide / Q000031:analogs & derivatives / Q000032:analysis*; D002747:Chlorpropamide / Q000032:analysis; D003460:Crystallization; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D014044:Tolbutamide / Q000032:analysis; D014961:X-Ray Diffraction; D000096926:Benzenesulfonamides
chemical_list: D000092:Acetohexamide; D002747:Chlorpropamide; D014044:Tolbutamide; C016564:N-methylacetohexamide; D000096926:Benzenesulfonamides