title: Structures of benzoxazine-fused triazoles as potential diuretic agents.
abstract: 6,8-Dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C(9)H(5)N(5)O(6), (I), a potential diuretic, and its acetylacetone derivative (E)-2-(2-hydroxy-4-oxopent-2-en-3-yl)-6,8-dinitro-2,4-dihydro-1H-benzo[b][1,2,4]triazolo[4,3-d][1,4]oxazin-1-one, C(14)H(11)N(5)O(8), (II), both crystallize from methanol but in centrosymmetric and noncentrosymmetric space groups, respectively. To the best of our knowledge, this is the first report of crystal structures of benzoxazine-triazole fused systems. The acetylacetone group in (II) exists as the keto-enol tautomer and is oriented perpendicular to the triazol-3-one ring. Of the two nitro groups present, one is rotated significantly less than the other in both structures. The oxazine ring adopts a screw-boat conformation in (II), whereas it is almost planar in (I). N-H···N and N-H···O hydrogen bonds form centrosymmetric dimers in (I), while C-H···O interactions associate the molecules into helical columns in (II).
authors.affiliation: Laboratory of X-ray Crystallography, CSIR Indian Institute of Chemical Technology, Hyderabad, India. sshiya@yahoo.com
authors.forename: Krishnan
authors.initials: K
authors.lastname: Ravikumar
authors.forename: Balasubramanian
authors.initials: B
authors.lastname: Sridhar
authors.forename: Jagadeesh Babu
authors.initials: JB
authors.lastname: Nanubolu
authors.forename: Venkatasubramanian
authors.initials: V
authors.lastname: Hariharakrishnan
authors.forename: Awadesh Narain
authors.initials: AN
authors.lastname: Singh
mesh_terms: D048588:Benzoxazines / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004232:Diuretics / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D010078:Oxazines / Q000737:chemistry*; D014230:Triazoles / Q000737:chemistry*
chemical_list: C576281:(E)-2-(2-hydroxy-4-oxopent-2-en-3-yl)-6,8-dinitro-2,4-dihydro-1H-benzo(b)(1,2,4)triazolo(4,3-d)(1,4)oxazin-1-one; C576280:6,8-dinitro-2,4-dihydro-1H-benzo(b)(1,2,4)triazolo(4,3-d)(1,4)oxazin-1-one; D048588:Benzoxazines; D004232:Diuretics; D010078:Oxazines; D014230:Triazoles