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.

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}.

Crystal structure of 2-chloro-3-(di-meth-oxy-meth-yl)-6-meth-oxy-quinoline.

The title compound, C13H14ClNO3, crystallizes with Z' = 2 in the space group Pca21, but a search for possible additional crystallographic symmetry found none. However, the crystal structure exhibits pseudosymmetry as the two independent mol-ecules are related by an approximate but non-crystallographic inversion located close to (0.38, 0.