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, Structural chemistry Structural chemistry, 2023-02, Vol.79 (Pt 3), p.94-103
• Main Authors: Vera, Diana R., Ardila, Diana M., Palma, Alirio, Cobo, Justo, Glidewell, Christopher
• Format: Article
• Language: English
• Subjects: Research Papers
• ISSN: 2053-2296
• DOI: 10.1107/S2053229623001432

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. 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, C 25 H 19 N, (IIa), and its di­chloro analogue, 2-[( E )-2,4-di­chloro­styr­yl]-4-[( E )-styr­yl]quino­line, C 25 H 17 Cl 2 N, (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, C 32 H 22 BrNO, (IIc), {2-[( E )-4-bromo­styr­yl]-4-[( E )-4-chloro­styr­yl]quinolin-3-yl}(phen­yl)methanone, C 32 H 21 BrClNO, (IId), and {2-[( E )-4-bromo­styr­yl]-4-[( E )-2-(thio­phen-2-yl)vin­yl]quinolin-3-yl}(phen­yl)methanone, C 30 H 20 BrNOS, (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 R 2 2 (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.