Structural comparison of five new halogenated dihydroquinoline-4(1H)-ones.

Compounds with dihydroquinoline-4(1H)-one nuclei have been reported in the literature for being important in the development of medicines due to their broad spectrum of activities. In this way, the structural knowledge of this class becomes relevant for obtaining new materials with desired biological properties. This study presents the structural elucidation of five halogenated dihydroquinolines, as well as the discussion about the effect on the molecular conformation of the type and position of halogen atom on aromatic rings. Compounds I and IV differ in halogen substitution on 2-phenyl ring, while compounds III and V differ in halogen substitution on the benzylidene ring. Moreover, compound II has a para-substituted 2-phenyl ring in their molecular structure. The crystal packing of all five molecules is mainly ruled by C-H⋯O and C-H···halogen interactions that form dimers and chains. The shift in position and the kind of the halogen in ring C shows a starring role in the conformation of the studied compounds, and the packaging of these compounds is more susceptible to variations when the halogen position changes.

Analysis of two novel 1-4 quinolinone structures with bromine and nitrobenzyl ligands.

The scientific community has shown particular interest in the study of quinolinones-a class of bicyclic organic compounds. An example of these compounds are the 4-quinolinones, considered to be very useful building blocks, since they can adapt their molecular structures with different ligands for applications in various fields such as pharmacy, medicine, physics and engineering. The compounds (E)-3-(benzylidene)-2-(3-nitrophenyl)-2,3-dihydro-1-(phenylsulfonyl)-quinolin-4-(1H)-one (NFQ) and (E)-3-(benzylidene)-2-(4-bromophenyl)-2,3-dihydro-1-(phenylsulfonyl) quinolin-4-(1H)-one (BFQ) were synthesized and characterized by infrared spectroscopy, 1H and 13C NMR, and melting point. NFQ crystallized in the orthorhombic Pbca space group while BFQ appears in the monoclinic P21/n space group. X-ray diffraction was used to evaluate their crystallographic structures, and Hirshfeld surface evaluates the intermolecular interactions, supramolecular arrangement and packaging. Theoretical vibrational assignments and calculated electronic properties also demonstrate acceptable agreement between experimental and theoretical results.