Bromination of 2-phenyl-1,2,3,4-tetrahydroquinolines

Abstract

Bromination of 2-phenyltetrahydroquinolines derivatives was investigated. During the bromination of 2-phenyl-1,2,3,4-tetrahydroquinoline with bromine in chloroform or bromosuccinimide along with the formation of di-and tribrom derivatives the oxidation reaction occurs with the generation of quinoline structure. The interaction of 2-phenyl-1,2,3,4-tetrahydroquinoline with bromine in acetic acid leads to the formation of 6,8-dibromoderivative preserving the 1,2,3,4-tetrahydroquinoline ring. At the same time Nsubstituted 2-phenyl-1,2,3,4-tetrahydroquinoline is selectively brominated in various conditions with the formation of 6-monobromoderivative. By the method of X-ray diffraction analysis the molecular structure of 3,6,8-tribromo-2-phenylquinoline single crystals was determined.

Progress in the Chemistry of Tetrahydroquinolines

“…They obtained 6- or 8-nitro-THQs, together with small amounts of the 6,8-dinitro derivative . The reaction of THQs with Br 2 and NBS under various reaction conditions allowed the transformation of 1,2,3,4-tetrahydroquinolines into the corresponding 6,8-dibromoquinoline and 3,6,8-tribromoquinolines in good yield through dehydrogenative bromination processes …”

Synthesis of Polysubstituted Quinolines from α-2-Aminoaryl Alcohols Via Nickel-Catalyzed Dehydrogenative Coupling

“…After 16 h, purification by column chromatography using 2% ethyl acetate in hexanes yielded 4fa (94 mg, 84%) as a white solid: 1 H NMR (400 MHz, CDCl 3 ) δ 8.20 (d, J = 8.5 Hz, 1H), 8.16 (d, J = 7.3 Hz, 2H), 7.85 (d, J = 8.7 Hz, 1H), 7.80 (dd, J = 9.5, 2.7 Hz, 2H), 7.57−7.45 (m, 3H), 7.32 (td, J = 8.6, 2.6 Hz, 1H); 13 6,8-Dibromo-2-phenylquinoline (4ga). 44 GP 1 was followed using nickel catalyst 3 (4 mg, 2.0 mol %), (2-amino-3,5-dibromophenyl)methanol 1g (169 mg, 0.6 mmol), and acetophenone 2a (60 mg, 0.5 mmol). After 16 h, purification by column chromatography using 2% ethyl acetate in hexanes yielded 4ga (158 mg, 87%).…”

9-Amino-5,7-dibromo-1,2,3,4-tetrahydroacridine hemihydrate

“…Halogenated aromatics including a quinoline skeleton are used as precursors for various multifunctional heterocyclic compounds, undergoing metal-halogen exchanges (Ö kten et al, 2013), couplings (Zemtsova et al, 2015), and metal-assisted substitutions (Ö kten et al, 2013;Eisch, 1962). In addition, this class of aromatic compounds, used as starting materials for numerous compounds with pharmacological properties, has been of interest to chemists (Zong et al, 2006;Das & Parida, 2006).…”