research communications Acta Cryst. (2024). E80, 777–782 https://doi.org/10.1107/S2056989024005826 777 ISSN 2056-9890 Received 23 April 2024 Accepted 14 June 2024 Edited by J. Ellena, Universidade de Saˆo Paulo, Brazil Keywords: crystal structure; acylation; thienylallylamines; maleic acid amide; weak interactions; Hirshfeld surface analysis. CCDC reference: 2362911 Supporting information: this article has supporting information at journals.iucr.org/e Published under a CC BY 4.0 licence Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(4-fluorophenyl)-1,2,3,4-tetrahydro- quinolin-4-yl]pyrrolidin-2-one Anastasia A. Pronina, a Alexandra G. Podrezova, a Mikhail S. Grigoriev, b Khudayar I. Hasanov, c,d Nurlana D. Sadikhova, e Mehmet Akkurt f * and Ajaya Bhattarai g * a RUDN University, 6 Miklukho-Maklaya St., Moscow, 117198, Russian Federation, b Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy prospect 31-4, Moscow 119071, Russian Federation, c Western Caspian University, Istiqlaliyyat Street 31, AZ1001, Baku, Azerbaijan, d Azerbaijan Medical University, Scientific Research Centre (SRC), A. Kasumzade St. 14. AZ 1022, Baku, Azerbaijan, e Department of Chem- istry, Baku State University, Z. Xalilov Str, Az 1148 Baku, Azerbaijan, f Department of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Tu¨ rkiye, and g Department of Chemistry, M.M.A.M.C (Tribhuvan University) Biratnagar, Nepal. *Correspondence e-mail: akkurt@erciyes.edu.tr, ajaya.bhattarai@mmamc.tu.edu.np In the title compound, C 19 H 18 BrFN 2 O, the pyrrolidine ring adopts an envelope conformation. In the crystal, molecules are linked by intermolecular N—H���O, C—H���O, C—H���F and C—H���Br hydrogen bonds, forming a three- dimensional network. In addition, C—H���� interactions connect molecules into ribbons along the b-axis direction, consolidating the molecular packing. The intermolecular interactions in the crystal structure were quantified and analysed using Hirshfeld surface analysis. 1. Chemical context As a result of their presence in many plants, tetrahydro- quinoline derivatives have long been of great interest to organic chemists and biochemists. The tetrahydroquinoline moiety can be found in many alkaloids that possess anti- malarial and antimicrobial properties (Ghashghaei et al., 2018; Khalilov et al., 2021; Safavora et al., 2019). Various studies show that tetrahydroquinolines have a wide spectrum of biological activity, and some are already being used as phar- maceutical agents (Sridharan et al., 2011; Akbari Afkhami et al., 2017; Abdelhamid et al., 2011). Modification of tetra- hydroquinoline derivatives is effective in the search, design, and development of new drugs. However, thousands of compounds are required to find a structure that exhibits biological activity, which is why an efficient synthetic metho- dology for obtaining tetrahydroquinoline derivatives is necessary (Astudillo et al., 2009; Kouznetsov et al., 2004, 2007). One of the most widely used approaches for the synthesis of tetrahydroquinolines is the Povarov reaction, known as the aza-Diels–Alder reaction (Palacios et al., 2010; Zubkov et al., 2010; Zaitsev et al., 2009). Herein, we have synthesized 1-[6- bromo-2-(4-fluorophenyl)-1,2,3,4-tetrahydroquinolin-4-yl]- pyrrolidin-2-one (I) by the reaction of (E)-N-(4-bromophen- yl)-1-(4-fluorophenyl)methanimine with 1-vinylpyrrolidin-2- one in the presence of the most commonly used Lewis acid, diethyl ether of boron trifluoride (Fig. 1). The mild conditions and efficiency of the cycloaddition of aromatic imines with electronically enriched alkenes make the Povarov reaction a useful tool in the synthesis of tetrahydroquinolines, optimi- zation of the search for potential drugs, and obtaining hits. It should be mentioned that the conformation of the obtained