title: Reactions between arylhydrazinium chlorides and 2-chloroquinoline-3-carbaldehydes: molecular and supramolecular structures of a hydrazone, a 4,9-dihydro-1H-pyrazolo[3,4-b]quinoline and two 1H-pyrazolo[3,4-b]quinolines.
abstract: Hydrazone derivatives exhibit a wide range of biological activities, while pyrazolo[3,4-b]quinoline derivatives, on the other hand, exhibit both antimicrobial and antiviral activity, so that all new derivatives in these chemical classes are potentially of value. Dry grinding of a mixture of 2-chloroquinoline-3-carbaldehyde and 4-methylphenylhydrazinium chloride gives (E)-1-[(2-chloroquinolin-3-yl)methylidene]-2-(4-methylphenyl)hydrazine, C17H14ClN3, (I), while the same regents in methanol in the presence of sodium cyanoborohydride give 1-(4-methylphenyl)-4,9-dihydro-1H-pyrazolo[3,4-b]quinoline, C17H15N3, (II). The reactions between phenylhydrazinium chloride and either 2-chloroquinoline-3-carbaldehyde or 2-chloro-6-methylquinoline-3-carbaldehyde give, respectively, 1-phenyl-1H-pyrazolo[3,4-b]quinoline, C16H11N3, (III), which crystallizes in the space group Pbcn as a nonmerohedral twin having Z' = 3, or 6-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinoline, C17H13N3, (IV), which crystallizes in the space group R\overline{3}. The molecules of compound (I) are linked into sheets by a combination of N-H...N and C-H...π(arene) hydrogen bonds, and the molecules of compound (II) are linked by a combination of N-H...N and C-H...π(arene) hydrogen bonds to form a chain of rings. In the structure of compound (III), one of the three independent molecules forms chains generated by C-H...π(arene) hydrogen bonds, with a second type of molecule linked to the chains by a second C-H...π(arene) hydrogen bond and the third type of molecule linked to the chain by multiple π-π stacking interactions. A single C-H...π(arene) hydrogen bond links the molecules of compound (IV) into cyclic centrosymmetric hexamers having \overline{3} (S6) symmetry, which are themselves linked into a three-dimensional array by π-π stacking interactions.
authors: Department of Chemistry, Jain University, 52 Bellary Road, Hebbal, Bangalore 560 024, India.
authors: Tholappanavara H Suresha
authors: TH
authors: Kumara
authors: Department of Chemistry, Jain University, 52 Bellary Road, Hebbal, Bangalore 560 024, India.
authors: Gopalpur
authors: G
authors: Nagendrappa
authors: Department of Chemistry, Jain University, 52 Bellary Road, Hebbal, Bangalore 560 024, India.
authors: Nanjappa
authors: N
authors: Chandrika
authors: Department of Chemistry, Jain University, 52 Bellary Road, Hebbal, Bangalore 560 024, India.
authors: Haliwana B V
authors: HB
authors: Sowmya
authors: Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA.
authors: Manpreet
authors: M
authors: Kaur
authors: Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA.
authors: Jerry P
authors: JP
authors: Jasinski
authors: School of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland.
authors: Christopher
authors: C
authors: Glidewell
keywords: aromatic π–π stacking interactions; crystal structure; hydrazones; hydrogen bonding; molecular conformation; molecular structure; pyrazoloquinolines; synthesis; twinning