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Synthesis and Crystal Structure of A Pyrithione Derivative: Bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-)
Synthesis and Crystal Structure of A Pyrithione Derivative:...
Balewski, Łukasz;Sączewski, Franciszek;Gdaniec, Maria
2019-06-25 00:00:00
molbank Short Note Synthesis and Crystal Structure of A Pyrithione Derivative: Bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5- dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) 1 , 1 ,y 2 Łukasz Balewski *, Franciszek Saczewski ˛ and Maria Gdaniec Department of Chemical Technology of Drugs, Faculty of Pharmacy, Medical University of Gdansk, ´ 80-416 Gdansk, ´ Poland Faculty of Chemistry, A. Mickiewicz University, 61-614 Poznan, ´ Poland; magdan@amu.edu.pl * Correspondence: lbalewski@gumed.edu.pl; Tel.: +48-58-349-1952; Fax: +48-58-349-1654 y Deceased 18 October 2018. Received: 31 May 2019; Accepted: 20 June 2019; Published: 25 June 2019 Abstract: The pyrithione derivative, bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H- imidazol-3-ium} tetrachlorocuprate(2-) (1a) has been obtained by the reaction of one equivalent of 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride with one and a half equivalents of copper (II) chloride dihydrate in methanol in a very good yield. The structure of this product was confirmed by X-ray crystallography, infrared spectroscopy, and elemental analysis. Keywords: pyrithione derivative; imidazoline derivative; tetrachlorocuprate(2-); X-ray crystallography 1. Introduction Coordination chemistry of pyrithione (N-hydroxypyridine-2(1H)-thione (Hmpo)), its heavy metal salts, and complexes have been widely investigated. Hmpo constitutes a universal O, S-donor ligand [1–4]. The infrared spectra of Hmpo indicates that the compound exists predominantly in its tautomeric thione form [5,6]. Recent UV spectra of pyrithione have shown that tautomeric equilibrium depends on the solvent used. Thione form dominates in polar and protic solvents, whereas 2-mercaptopyridine N-oxide exists in non-polar solvents [7]. Strong bactericidal and fungicidal properties of pyrithione have been well demonstrated [8]. Pyrithione acts as a proton conductor and inhibits the membrane transport processes in fungi. However, it was found that fungi can detoxify this agent at low concentration [9]. A zinc complex of N-hydroxypyridine-2(1H)-thione (zinc pyrithione) is widely used in dandru shampoos for treating dandru and seborrhoeic dermatitis [10]. Moreover, it was demonstrated that zinc pyrithione exhibits also antibacterial properties. Zinc pyrithione is a good example of an antibiofilm agent, which improves the antibacterial activity of silver sulfadiazine ointment [11]. Copper pyrithione has been recently considered in supplanting zinc pyrithione in view of its low toxicity [12]. Pyrithione derivative, 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide, as a free base [CAS Registry Number 90764-93-5] [13–15] and its water-soluble acid addition salts, hydrobromide [CAS Registry Number 6937-05-9] [13–16] and hydrochloride [CAS Registry Number 62377-10-0] [17], are regarded as useful chemical agents that control microbial growth. They possess both fungistatic and bacteriostatic eects and may serve as preservatives. 2. Results and Discussion The title compound: bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a) was synthesized by slow evaporation of methanolic solution of the Molbank 2019, 2019, M1067; doi:10.3390/M1067 www.mdpi.com/journal/molbank Molbank 2019, 2019, x 2 of 5 The title compound: bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} Molbank 2019, 2019, M1067 2 of 5 tetrachlorocuprate(2-) (1a) was synthesized by slow evaporation of methanolic solution of the 2-[(4,5- dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) with excess of copper (II) chloride 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) with excess of copper (II) dihydrate. chloride dihydrate. For the preparation of 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide (as free base or For the preparation of 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide (as free base or acid acid addition salt), 2-bromopyridine 1-oxide was reacted with an imidazolidine-2-thione in a addition salt), 2-bromopyridine 1-oxide was reacted with an imidazolidine-2-thione in a halogenated halogenated hydrocarbon solvent (chloroform) or in ethanol. According to the literature’s data, the hydrocarbon solvent (chloroform) or in ethanol. According to the literature’s data, the mixture required mixture required heating for 12 hours to give acid addition salt (hydrobromide). The free base may heating for 12 h to give acid addition salt (hydrobromide). The free base may be obtained in dioxane be obtained in dioxane by treatment with an equivalent of dimethylaniline [13,14]. by treatment Generallwith y, 2-an [(4equivalent ,5-dihydro-of 1H dimethylaniline -imidazol-2-yl)th [13 io,]14 pyr ]. idine 1-oxide hydrochloride (1) [CAS Generally, 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) [CAS Registry Registry Number 62377-10-0] can be synthesized as a result of the nucleophilic attack of the sulfur Number atom of 62377-10-0] 2-mercaptocan pyribe dinsynthesized e 1-oxide oas n aC2 result carb of on the ofnucleophilic 2-chloro-4,5 attack -dihydr ofothe -1H- sulfur imidaz atom ole (2 of - 2-mercaptopyridine 1-oxide on C2 carbon of 2-chloro-4,5-dihydro-1H-imidazole (2-chloroimidazoline). chloroimidazoline). The reaction was carried out in dichloromethane at room temperature in high The yield reaction and thwas e pro carried duct 1 out prec in ip dichlor itated omethane after mixin at g room the re temperatur actants. Thi e in s m high etho yield d pro and vides theapr ce oduct rtain 1 precipitated after mixing the reactants. This method provides a certain advantage over traditional advantage over traditional thermal heating. The reaction completes within a significantly shorter thermal time. In theating. he next step The , bro reaction wn singl completes e crystals o within f the bi as{2 signific -[(1-oxantly idopyr shorter idin-2-yl time. )sulfaIn nylthe ]-4,5next -dihydr step, o- brown single crystals of the bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} 1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a) suitable for X-ray diffraction analysis were obtained tetrachlor by slow ocuprate(2-) evaporation( 1a o)f suitable methan for olic X-ray soluti di on raction , conta analysis ining twer he e2obtained -[(4,5-dihby ydrslow o-1Hevaporation -imidazol-2- of methanolic solution, containing the 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide yl)thio]pyridine 1-oxide hydrochloride (1) and copper (II) chloride dihydrate at room temperature hydr (Scheme ochloride 1). (1) and copper (II) chloride dihydrate at room temperature (Scheme 1). Scheme 1. Synthesis of the 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) Scheme 1. Synthesis of the 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) and bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a). and bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a). The crystal structure of the bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a) is shown in Figure 1a (see also supplementary crystallographic data). The The crystal structure of the bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3- asymmetric unit of 1a consists of the organic cation and one half of the C symmetric [CuCl ] anion. 2 4 ium} tetrachlorocuprate(2-) (1a) is shown in Figure 1a (see also supplementary crystallographic data). In the 2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium cation, the two rings attached 2− The asymmetric unit of 1a consists of the organic cation and one half of the C2 symmetric [CuCl4] to the S atom are nearly perpendicular with the dihedral angles between the imidazoline and pyridine anion. In the 2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium cation, the two rings best planes of 87.1 and the pyridine N-oxide group is oriented anti-relative to the imidazolinium attached to the S atom are nearly perpendicular with the dihedral angles between the imidazoline ring. The conformation adopted by the cation results in a large deviation from 120 of the endocyclic and pyridine best planes of 87.1° and the pyridine N-oxide group is oriented anti-relative to the bond angles at the pyridine C2 atom, [N1-C2-S7 111.01(11) and C3-C2-S7 129.23(11) ], and in short imidazolinium ring. The conformation adopted by the cation results in a large deviation from 120° of intramolecular contact H3C8 of 2.51 Å. The most probable reason for these angular deviations is the endocyclic bond angles at the pyridine C2 atom, [N1-C2-S7 111.01(11)° and C3-C2-S7 129.23(11)°], repulsive interactions between H3 and C8. The cations are connected by a pair of N-HO hydrogen and in short intramolecular contact H3···C8 of 2.51 Å. The most probable reason for these angular i i i bonds [N9O1 2.7714(16) Å, H9O1 1.91 Å, <N9-H9O1 166 ; symmetry code i: x+1/2, y+3/2, deviations is repulsive interactions between H3 and C8. The cations are connected by a pair of N- 2- + z] into centrosymmetric dimers that, in turn, interact with [CuCl ] anions via N-H Cl bonds i i i H···O hydrogen bonds [N9···O1 2.7714(16) Å, H9· · · O1 1.91 Å, <N9-H9· · · O1 166°; symmetry code i: i i [N12Cl1 3.2622(12) Å, <N12-H12 Cl1 156 ; symmetry code i: x, y+1, z], forming chains extended 2- −x+1/2, −y+3/2, −z] into centrosymmetric dimers that, in turn, interact with [CuCl 4] anions via N- along [1 0 1] (Figure 1b). In addition, there is a short contact C2-S7 Cl2i [S2 Cl2i 3. 3279(5) Å, < + − i i H ···Cl bonds [N12· · · Cl1 3.2622(12) Å , <N12-H12· · · Cl1 156°; symmetry code i: x, y+1, z], forming C2-S7 Cl2i 169.60(5) symmetry code i: x, y+1, z] pointing to a weak chalcogen bonding between chains extended along [1 0 1] (Figure 1b). In addition, there is a short contact C2-S7· · · Cl2i [S2· · · Cl2i cations and anions from adjacent chains. Molbank 2019, 2019, x 3 of 5 Molbank 3. 3272019 9(5), Å 2019 , <, C2 M1067 -S7· · · Cl2i 169.60(5)° symmetry code i: −x, −y+1, −z] pointing to a weak chalcogen 3 of 5 bonding between cations and anions from adjacent chains. (a) (b) Figure Figure1. 1.( a (a )) OR ORTEP TEP [[18 18] ] r repr epresentation esentation o of f th the e m molecular olecular ststr ruc uctur ture o ef of 1a1a. . Dis Displacement placement ellip ellipsoids soids are are shown at the 50% probability level; ‘i’ relates to symmetry generated atoms. (b) Crystal packing shown at the 50% probability level; ‘i’ relates to symmetry generated atoms. (b) Crystal packing viewed viewed along the b axis with hydrogen bonds shown as dashed lines. Chains of hydrogen-bonded along the b axis with hydrogen bonds shown as dashed lines. Chains of hydrogen-bonded ionic species ionic species are extended along [1 0 1]. are extended along [1 0 1]. 3. Materials and Methods 3. Materials and Methods 3.1. General Methods and Physical Measurements 3.1. General Methods and Physical Measurements All reagents and solvents were purchased from commercial sources and used without further All reagents and solvents were purchased from commercial sources and used without further purification. purification. The The IR IR spectra spectra were were re recor cord ded ed oon n a aNi Nicolet colet 3380FT 80FT-IR -IR spec spectr tropho ophotometer tometer. The . The H NM H NMR R spectrum of compound 1 was registered at 20–22 °C on Varian Gemini 200 ( H = 200 MHz), using the spectrum of compound 1 was registered at 20–22 C on Varian Gemini 200 ( H = 200 MHz), using the signal of DMSO-d6 as an internal standard. The values of chemical shifts are given in ppm and signal of DMSO-d as an internal standard. The values of chemical shifts are given in ppm and coupling coupling constants (J) are expressed in hertz (Hz). Measured C, H, N elemental analyzes were within constants (J) are expressed in hertz (Hz). Measured C, H, N elemental analyzes were within 0.40% of 0.40% of calculated values. The diffraction data for single crystals of 1a were collected with an Oxford calculated values. The diraction data for single crystals of 1a were collected with an Oxford Diraction Diffraction XcaliburE diffractometer using Mo Kα radiation. The intensity data were collected and XcaliburE diractometer using Mo K radiation. The intensity data were collected and processed processed using CrysAlisPro Software [19]. The structure was solved by direct methods with the using CrysAlisPro Software [19]. The structure was solved by direct methods with the program program SHELXS-97 [20] and refined by the full-matrix least-squares method on F with SHELXL- SHELXS-97 [20] and refined by the full-matrix least-squares method on F with SHELXL-2018 [21]. All 2018 [21]. All H atoms were refined as riding on their carriers. H atoms were refined as riding on their carriers. 3.2. Synthesis of 2-[(4,5-Dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) 3.2. Synthesis of 2-[(4,5-Dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (1) 2-Chloro-4,5-dihydro-1H-imidazole sulfate [22] (5.1 g, 25 mmol) was added gradually to a 5% 2-Chloro-4,5-dihydro-1H-imidazole sulfate [22] (5.1 g, 25 mmol) was added gradually to a solution of sodium hydroxide at a temperature of 5 °C and extracted with dichloromethane (4 × 20 5% solution of sodium hydroxide at a temperature of 5 C and extracted with dichloromethane mL). The combined organic phases were dried over anhydrous magnesium sulfate. After filtration, (4 20 mL). The combined organic phases were dried over anhydrous magnesium sulfate. After the solvent was evaporated under reduced pressure to a volume of 30 mL. 2-Mercaptopyridine 1- filtration, the solvent was evaporated under reduced pressure to a volume of 30 mL. 2-Mercaptopyridine oxide (3.18 g, 25 mmol) was added to the resulting solution of 2-chloro-4,5-dihydro-1H-imidazole in 1-oxide (3.18 g, 25 mmol) was added to the resulting solution of 2-chloro-4,5-dihydro-1H-imidazole dichloromethane. When the exothermic reaction had subsided, the white precipitate was filtered, in dichloromethane. When the exothermic reaction had subsided, the white precipitate was filtered, washed with dichloromethane, and dried. The product was obtained as a white solid and yield was washed with dichloromethane, and dried. The product was obtained as a white solid and yield was −1 5 g (86%); mp. 172–175 °C; IR (KBr) ν (cm ): 3000, 2891, 2835, 2634, 1595, 1561, 1466, 1417, 1289, 1249, 5 g (86%); mp. 172–175 C; IR (KBr) 1 (cm ): 3000, 2891, 2835, 2634, 1595, 1561, 1466, 1417, 1289, 1249, 1213, 1201, 1084, 1025, 840, 762; H NMR (200 MHz, DMSO-d6) δ (ppm): 3.93 (s, 4H, 2×CH2); 7.42–7.60 1213, 1201, 1084, 1025, 840, 762; H NMR (200 MHz, DMSO-d ) (ppm): 3.93 (s, 4H, 2CH ); 7.42–7.60 (m, 2H, arom.); 7.93 (dd, J1 = 1.8 Hz, J2 = 8.0 Hz, 1H, arom.); 8.4 69 (d, J = 5.5 Hz, 1H, arom.); 102 .87 (br.s, (m, 2H, arom.); 7.93 (dd, J = 1.8 Hz, J = 8.0 Hz, 1H, arom.); 8.49 (d, J = 5.5 Hz, 1H, arom.); 10.87 (br.s, 2H, 2×NH ). Anal. calcula 1ted for C8H10 2ClN3OS (231.70): C, 41.47; H, 4.35; N, 18.14. Found: C: 41.41; H, 2H, 2NH ). Anal. calculated for C H ClN OS (231.70): C, 41.47; H, 4.35; N, 18.14. Found: C: 41.41; 4.32; N, 17.87. 8 10 3 H, 4.32; N, 17.87. 3.3. Synthesis of Bis{2-[(1-oxidopyridin-2-yl)sulfanyl]-4,5-dihydro-1H-imidazol-3-ium} tetrachlorocuprate(2-) (1a) Copper(II) chloride dihydrate (0.553 g, 3.24 mmol) was dissolved in 1 mL of anhydrous methanol and the solution was gradually added (dropwise) to a solution of Molbank 2019, 2019, M1067 4 of 5 2-[(4,5-dihydro-1H-imidazol-2-yl)thio]pyridine 1-oxide hydrochloride (0.5 g, 2.16 mmol) (1) in anhydrous methanol (10 mL) at a temperature of 40 C. Upon slow evaporation of the solvent over 24 h at room temperature (20–22 C), brown crystals were formed. Precipitate was filtered o, washed with methanol (2 0.5 mL), and dried in a desiccator. The product was obtained as a brown crystals and yield was 0.46 g (71%); mp. 143–148 C; IR (KBr) (cm ): 3175, 3068, 3033, 2869, 2596, 1591, 1553, 1471, 1421, 1278, 1211, 1154, 1093, 1019, 834, 772; H NMR (200 MHz, DMSO-d ) (ppm): 3.95 (s, 4H, 2CH ); 7.46–7.57 (m, 2H, arom.); 7.92 (d, J = 7.0 Hz, 1H, arom.); 8.49 (d, J = 5.7 Hz, 1H, arom.); 10.69 (br.s, 2H, 2NH ). Anal. calculated for C H Cl CuN O S (595.84): C, 32.25; H, 3.04; 16 18 4 6 2 2 N, 14.10. Found: C, 32.18; H, 2.99; N, 14.12. Crystal data for 1a: 2(C H N OS)CuCl , monoclinic, space group C2/c, a = 20.9638(10), 8 10 3 4 3 3 b = 6.8597(3), c = 15.9721(7) Å, = 106.708(5) , V = 2199.90(17) Å , Z = 4, T = 130 K, d = 1.805 gcm , (Mo K) = 1.697 mm , 8519 were collected up to = 27.0 (R = 0.0159, R = 0.0164). Final R max int indices for 2364 reflections with I > 2(I) and 141 refined parameters were: R = 0.0191, wR = 0.0505 1 2 (R = 0.0222, wR = 0.0512 for all 2629 data). Crystallographic data for compound 1a have been 1 2 deposited with the Cambridge Crystallographic Data Centre, with the deposition No. CCDC 1914490. Supplementary Materials: Supplementary files are available online. CCDC 1914490 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via the Cambridge Crystallographic Data Centre http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44 1223 336033; E-mail: deposit@ccdc.cam.ac.uk). Author Contributions: F.S. and L.B. conceived and designed the experiments; L.B. performed the experiments; M.G. analyzed the data; L.B. and M.G. wrote the paper. Funding: The publication of this article was supported by the Funds for Statutory Activity of the Medical University of Gdansk ´ (ST-020038/07). Acknowledgments: The NMR spectra were carried out at The Nuclear Magnetic Resonance Laboratory, Gdansk ´ University of Technology, Poland. Conflicts of Interest: The authors declare no conflict of interest. References 1. Chen, X.C.; Hu, Y.; Wu, D.; Weng, L.; Kang, B. Syntheses and electrochemistry of some transition metal complexes with 2-mercaptopyridine N-oxide and crystal structure of bis(2-mercaptopyridine N-oxide)nickel(II). Polyhedron 1991, 10, 2651–2657. [CrossRef] 2. Lobana, T.S.; Singh, R. Chemistry of pyridinethiols and related ligands-4. Complexes of bis(pyridine-2-thiolato- or 1-oxopyridine-2-thione) ruthenium(II) with bis(diphenylphosphino)alkanes. Polyhedron 1995, 14, 907–912. [CrossRef] 3. Barnett, B.L.; Kretschmar, H.C.; Hartman, F.A. Structural characterization of bis(N-oxopyridine-2-thionato)zinc(II). Inorg. Chem. 1977, 16, 1834–1838. [CrossRef] 4. Niu, D.-Z.; Yao, L.; Min, X.; Zou, H. Crystal structure of cis-bis [1-hydroxypyridine-2(1H)-thionato-S,O]copper(II), Cu(C H NOS) . Z. Kristall. NCS 2011, 226, 5 4 2 527–528. [CrossRef] 5. Jones, R.A.; Katritzky, A.R. Tautomeric pyridines. Part I. 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Crystal structure refinement with SHELXL. Acta Crystallogr. 2014, C71, 3–8. 22. Trani, A.; Bellasio, E. Synthesis of 2-chloro-2-imidazoline and its reactivity with aromatic amines, phenols, and thiophenols. J. Heterocycl. Chem. 1974, 11, 257–261. [CrossRef] © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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