388 Rearrangement in the Series of Acetyltetrahydropyridine Derivatives F. N. Naghiyev a ,* A. M. Maharramov a , Kh. A. Asadov a , and I. G. Mamedov a a Baku State University, ul. Z. Khalilova 23, Baku, AZ 1148, Azerbaijan *e-mail: farid.orgchemist@gmail.com Received July 25, 2018; revised August 4, 2018; accepted November 16, 2018 Abstract—Michael addition of various substituted benzylidene- and thiophen-2-ylmethylidenemalononitriles with acetoacetanilide gave the corresponding 5-acetyl-2-amino-4-aryl(hetaryl)-6-oxo-1-phenyl-1,4,5,6-tetra- hydropyridine-3-carbonitriles. Treatment of the latter with ethylenediamine in boiling methanol resulted in their rearrangement with elimination of the acetyl group and formation of 2-anilino-4-aryl(hetaryl)-6-oxo-1,4,5,6- tetrahydropyridine-3-carbonitriles. The product structure was proved by NMR spectroscopy and X-ray analysis. Keywords: benzylidenemalononitriles, thiophen-2-ylmethylidenemalononitriles, acetoacetanilide, ethylenedi- amine, tetrahydropyridines. SHORT COMMUNICATIONS It is known that derivatives of pyridine and its hydrogenated analog, piperidine, are important as compounds possessing a high biological activity. In particular, they act as immunomodulators and anticon- vulsant, antimalarial, antiviral, cytostatic, antigeno- toxic, and anticancer agents [1]. Taking into account increase in the number of bacterial pathogens resistant to many drugs, the need of new compounds capable of inhibiting such bacteria has grown in recent time. Recent studies have demonstrated a high efficiency of tetrahydropyridine derivatives as antibacterial and anti- tubercular agents in comparison to the existing drugs (e.g., Rifampicin) [2]. Various methods for the synthesis of polysubsti- tuted pyridines have been reported, in particular base- catalyzed multicomponent reactions [3–10]. The use of thiophenes and thiols in these reactions makes it pos- sible to obtain valuable sulfur-containing pyridine derivatives [11–14]. 2,4,6-Triaryl- and cyanopyridines were synthesized by three-component condensation of chalcones with ammonia and aldehydes or ketones under conditions of homogeneous or heterogeneous catalysis [15, 16]. By Michael addition of substituted benzylidene- and tiophen-2-ylmethylidenemalononitriles to aceto- acetanilide according to the procedure described in [3] we synthesized the corresponding 1,4,5,6-tetrahydro- pyridine-3-carbonitriles 1a–1g. The reaction of 1a–1g with ethylenediamine (2) in boiling methanol was accompanied by rearrangement with elimination of the acetyl group and formation of new pyridine derivatives 3a–3g (Scheme 1). Presumably, the hemiaminal intermediate formed by addition of ethylenediamine to the acetyl carbonyl R = Ph (a), 4-MeC 6 H 4 (b), 4-FC 6 H 4 (c), 4-BrC 6 H 4 (d); 3-IC 6 H 4 (e), 2,6-Cl 2 C 6 H 3 (f), thiophen-2-yl (g). ISSN 1070-4280, Russian Journal of Organic Chemistry, 2019, Vol. 55, No. 3, pp. 388–391. © Pleiades Publishing, Ltd., 2019. Russian Text © The Author(s), 2019, published in Zhurnal Organicheskoi Khimii, 2019, Vol. 55, No. 3, pp. 451–455. DOI: 10.1134/S1070428019030217 Scheme 1. N NC H 2 N R Me O O Ph 1a–1g + H 2 N NH 2 MeOH, reflux –H 2 N(CH 2 ) 2 NHAc 2 N H NC N H R O 3a–3g Ph