Conversion of 2‐methyl‐4‐styrylquinolines into 2,4‐distyrylquinolines: synthesis, and spectroscopic and structural characterization of five examples

• Published in: Acta crystallographica. Section C, Crystal structure communications Crystal structure communications, 2023-03, Vol.79 (3), p.94-103
• Main Authors: Vera, Diana R., Ardila, Diana M., Palma, Alirio, Cobo, Justo, Glidewell, Christopher
• Format: Article
• Language: English
• Subjects: Aldehydes; Chemical bonds; Chemical reactions; Chlorides; Condensates; crystal structure; Crystallography; Diketones; heterocyclic compounds; Hydrogen; hydrogen bonding; Hydrogen bonds; Indium; Links; molecular conformation; NMR spectroscopy; privilaged scaffold; Quinoline; quinolines; Sheets; Spectroscopy; Structural analysis; styrylquinolines; supramolecular assembly; synthesis
• ISSN: 2053-2296; 0108-2701; 2053-2296; 1600-5759
• DOI: 10.1107/S2053229623001432

Four new 2,4‐distyrylquinolines and one 2‐styryl‐4‐[2‐(thiophen‐2‐yl)vinyl]quinoline have been synthesized using indium trichloride condensation reactions between aromatic aldehydes and the corresponding 2‐methylquinolines, which were themselves prepared using Friedländer annulation reactions between mono‐ or diketones and (2‐aminophenyl)chalcones: the products have all been fully characterized by spectroscopic and crystallographic methods. 2,4‐Bis[(E)‐styryl]quinoline, C25H19N, (IIa), and its dichloro analogue, 2‐[(E)‐2,4‐dichlorostyryl]‐4‐[(E)‐styryl]quinoline, C25H17Cl2N, (IIb), exhibit different orientations of the 2‐styryl unit relative to the quinoline nucleus. In each of the 3‐benzoyl analogues {2‐[(E)‐4‐bromostyryl]‐4‐[(E)‐styryl]quinolin‐3‐yl}(phenyl)methanone, C32H22BrNO, (IIc), {2‐[(E)‐4‐bromostyryl]‐4‐[(E)‐4‐chlorostyryl]quinolin‐3‐yl}(phenyl)methanone, C32H21BrClNO, (IId), and {2‐[(E)‐4‐bromostyryl]‐4‐[(E)‐2‐(thiophen‐2‐yl)vinyl]quinolin‐3‐yl}(phenyl)methanone, C30H20BrNOS, (IIe), the orientation of the 2‐styryl unit is similar to that in (IIa), but the orientation of the 4‐arylvinyl units show considerable variation. The thiophene unit in (IIe) is disordered over two sets of atomic sites having occupancies of 0.926 (3) and 0.074 (3). There are no hydrogen bonds of any kind in the structure of (IIa), but in (IId), a single C—H…O hydrogen bond links the molecules into cyclic centrosymmetric R22(20) dimers. A combination of C—H…N and C—H…π hydrogen bonds links the molecules of (IIb) into a three‐dimensional framework structure. A combination of three C—H…π hydrogen bonds links the molecules of (IIc) into sheets, and a combination of C—H…O and C—H…π hydrogen bonds forms sheets in (IIe). Comparisons are made with the structures of some related compounds. Five new 4‐(arylvinyl)‐2‐styrylquinolines have been synthesized using indium chloride‐catalyzed condensation reactions between their 4‐(arylvinyl)‐2‐methyl‐ analogues and either mono‐ or diketones. The supramolecular arrangements range from isolated molecules via hydrogen‐bonded dimers and sheets to three‐dimensional framework structures.