Crown Ethers Краун-эфиры
Макрогэтэроцмклы
http://macroheterocycles.isuct.ru
Communication Сообщение
DOI: 10.6060/mhc170291i
Synthesis of Tetrakisbenzo-31(34)-crown-7(8) Ethers
Truong Hong Hieu,ac Nguyen T. T. Phuong,d Anatoly T. Soldatenkov|,e
Vasily E. Kotsuba,6 Elena I. Polyakova,6 Nguyen Van Tuyen,ab Tran T. Thanh Van,d
Dang T. Tuyet Anh,ab and Le Tuan Anhd@
aInstitute of Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
hGraduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Department of Biotechnology, Vietnam-Russia Tropical Centre, Hanoi, Vietnam
dFaculty of Chemistry, University of Science, Vietnam National University, Hanoi, Vietnam
eRUDN University, 117198 Moscow, Russia
@Corresponding author E-mail: [email protected]
Condensations of 1,5-bis(2-formylphenoxy)-3-oxapentane (1a) or 1,8-bis(2-formylphenoxy)-3,6-dioxanoctane (1b) podands and 1,8-bis(2-acetylphenoxy)-3,6-dioxanoctane (2) gave two novel crown ethers: tetrakis-(benzo)-31-crown-7 ether (5) and tetrakis(benzo)-34-crown-8 ether (6). Their molecular structures were established by IR, NMR and MS methods.
Keywords: Tetrakis(benzo)-31-crown-7 ether, tetrakis(benzo)-34-crown-8 ether, Petrenko-Kritchenko reaction, diketon, dialdehyde.
Синтез тетрабензо-31(34)-краун-7(8) эфиров
Т. Х. Хиеу,ас Н. Т. Т. Фыонг,й | А. Т. Солдатенков|,е В. Е. Коцюба,е Е. И. Полякова,
Н. В. Туен,аЬ Т. Т. Т. Ван,* Д. Т. Т. Ань,аЬ Л. Т. Ань*@
аИнститут химии, Вьетнамская академия науки и технологии, Ханой, Вьетнам ьВысший университет науки и техники, Вьетнамская академия наук и технологии, Ханой, Вьетнам сФакультет биотехнологии, Российско-Вьетнамский Тропический центр, Ханой, Вьетнам йФакультет химии, Университет науки, Вьетнамский национальный университет, Ханой, Вьетнам еРоссийский университет дружбы народов, 117198 Москва, Россия ®Е-тай: [email protected]
Конденсация подандов, 1,5-бис(2-формилфенокси)-3-оксапентана (1а) или 1,8-бис-(2-формилфенокси)-3,6-диоксаноктана (1Ь), с 1,8-бис(2-ацетилфенокси)-3,6-диоксаноктаном (2) привела к образованию двух новых краун-эфиров - тетракис(бензо)-31-краун-7 эфира (5) и тетракис(бензо)-34-краун-8 эфира (6). Их молекулярная структура была подтверждена методами ИК, ЯМР спектроскопии и масс-спектрометрии.
Ключевые слова: Тетракис(бензо)-31-краун-7 эфир, тетракис(бензо)-34-краун-8 эфир, реакция Петренко-Криченко, дикетон, диальдегид.
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In the previous publications,11-2-31 we have reported on the preparations of dibenzo[y-(aryl)pyrido]aza-14-crown-4 ethers from arylaldehyde, 1,5-bis(2-acetylphenoxy)-3-oxapentane and ammonium acetate by Petrenko-Kritchenko reaction. These new compounds containing y-phenylpyridine ring exhibited cytotoxicity to several cancer cell lines: Hepatocellular carcinoma (Hep-G2); Rhabdosarcoma (RD), Human Uterine (FL); Human Breast adenocarcinoma (MCF7).[13] In addition, using the similar domino reaction for synthesis of new azacrown ether, we have obtained a macroheterocyclic system containing two azacrown ether fragments.[4]
With the aim of preparing ditopic systems (3a,b), we have studied condensation of bis(2-formylphenoxy)-3,6-di-oxaoctane (1a) or bis(2-formylphenoxy)-3-oxapentane (1b) with bis(2-acetylphenoxy)-3-oxapentane and ammonium acetate. However, instead of the expected azacrown systems (3a,b) the tetrakis(benzo)crown ethers (4a,b) were isolated by column chromatography with the low yield (20-28 %).[56]
The structure of (4a,b) were determined by IR, NMR, MS and X-ray analysis. The volume of internal cavity of macrocycle (4b) is equal to 125 A3. The dihedral angles between the benzene planes of C1, C43-C47/C5-C10, C5-C10/C18-C23, C18-C23/C27-C32 and C27-C32/C1,C43-C47 are 64.91(8), 65.14(8), 61.64(8) and 56.67(9)°, respec-tively.[5,6]
To optimize the reaction and continue developing of novel tetrakis(benzo)crown ethers, the similar condensations of two dialdehydes (1a,b) with diketones (2) without ammonium acetate were studied. The reaction was stirred in system K2CO3/H2O/C2H5OH for 3 h at 50 °C. The formed yellow wax-like precipitate was separated and recrystallized from ethanol. Macroheterocycles 31-crown-7 ethers (5) and 34-crown-8 ether (6) were obtained in good yields (up to 88 %).
The structure of compounds (5, 6) was determined by NMR, IR spectrometry and MS spectrometry. Thus, in the 'H NMR spectra of macroheterocycle tetrakis(benzo)31-crown-7 ether (5) the signals of sixteen aromatic proton appeared in the region 5 6.85-7.54 ppm and four vinylketone protons (CH=CH-C=O) were observed in the weak field at 5 7.60 ppm and 5 7.78 ppm as two doublets (2H of each: H-2, H-3 and H-28, H-29). Spin-spin coupling constant 3J of
Figure 1. General view and crystallographic numeration of compound (4b) according to X-ray study data.
ethylene protons is equal to 16.5 Hz in both cases, which indicated the trans-position of -Ph and -(C=O)-Ph substitu-ents. Signals from the polyether groups (-CH2O-) appeared as four multiplets in the region 5 3.54-4.17 ppm. The 13C NMR spectra show many pairs of symmetric carbon atoms. All methylene carbon appear in the region of 5 68.65, 68.73, 69.27, 70.01, 70.70 ppm, and C b , (C4, C27) is observed
A A ' carbonyl v ' '
at 194.46 ppm. Its IR spectrum displays absorption bands at 1643 cm-1 which is characteristic for C=O bonds. HPLC-MS (ESI) gave a clear [M+Na]+ peak at 687.25671 which agrees with the overall molecular formula of 31-crown-7 ether (5). Compound (6) is a 34-membered crownophane with the vinylketone protons resonate in the weak field at 5 7.36 and 7.88 ppm with the spin-spin coupling constant 3J = 16.0 Hz in both cases. All the signals of aromatic proton appear in the region 5 6.80-7.56 ppm and the signals of twenty four methylene protons (-CH2O-) overlap each other and give rise to six multiplets in the region of 5 3.26-4.13 ppm. The
H H
O'
O
(1a, b)
Scheme 1. Synthesis of non-nitrogenous macroheterocycles under the Petrenko-Kritchenko conditions. Макрогетер0циmbl /Macroheterocycles 2017 70(1) 94-97
Synthesis of tetrakisbenzo-31(34)-crown-7(8)ethers
O O
45^/43
44
Scheme 2. Synthesis of tetrakis(benzo)-31-crown-7 ether and tetrakis(benzo)-34-crown-8 ether.
6
IR absorption band near 1654 cm-1 confirmed the presence of C=O functional groups. The structure of compound (6) was further supported by its LC-MS spectra (ESI), indicating the clear [M+H]+ ion peak at m/z 709.2.
All of non-nitrogenous macroheterocycles (4a,b, 5, 6) are interesting as effective complexing ligands in the coordination chemistry.
Experimental
Melting points were determined using a Raga melting point apparatus. IR spectra were recorded on Shimadzu FT IR PC (S) 8201spectrometer by using KBr pellets and the absorption frequencies are expressed in reciprocal centimeters (cm-1). NMR spectra was taken on BRUKER 500 MHz spectrometer using TMS as an internal reference. The chemical shifts were expressed in parts per million (ppm). ESI-MS were recorded in LTQ orbitrap XL mass spectrometer, Thermo Scientific Company
(2E,28E)-11,14,17,20,36,39,42-Heptaoxapentacyclo-[41.4 . 0 . 05 10.021-26.030-35]-heptatetraconta-l(43),2,5(10),6,8, 21,23,25,28,30,32,34,44,46-tetradecaen-2,28-dione (5). A solution of 1,5-bis(2-formylphenoxy)-3-oxapentane (1a) (0.41 g, 1.30 mmol) in ethanol (10 ml) and a solution of 1,8-bis(2-acetylphenoxy)-3,6-dioxanoctane (2) (0.50 g, 1.30 mmol) in ethanol (10 ml) were added simultaneously to a suspension of K2C03(5.0 g, 36 mmol) in 30 ml water/ethanol (1:1). The reaction mixture was magnetically stirred at 50 °C for 3 days. The formed precipitate was filtered off, washed with ethanol and chromatographically purified on silica gel (eluat-ing with hexane-ethylacetate, 2:1). Compound (5) was obtained as 0.74 g light-yellow crystals (85.0 %). Rf=0.64 («-hexane/EtOAc, 1:1). M.p. 126-128 °C. IR (KBr) v cm-1: 2920, 2870, 1643, 1599, 1485. 1H NMR (CDCl3, 500 MHz, 300 K) SH ppm: 3.54, 3.88, 4.00 and 4.17 (all m, 6H, 5H, 5H and 4H, respectively, -CH2CH20-); 6.85-7.54 (16H, m, H ), 7.60 and 7.78 (both d, 2H each, 0=C-
v 55 arom.-" v 5 5
CHtrans=CH, ,7=16.5 Hz). 13C NMR (CDCl3, 125 MHz, 300 K) SC
ppm: 68.65 (C38, C40), 68.73 (C13, 18), 69.27 (C15, C16), 70.01 (C12, C19), 70.70 (C37, C41),112.75 (C34, C44), 112.79 (C9, C22), 120.93 (C7, C24), 121.10 (C46, C32), 124.44 (C3, C28), 128.63 (C6, C25), 129.44 (C1, C30), 130.01 (C33, C45), 130.17 (C5, C26), 131.43 (C31, C47), 132.27 (C8, C23), 139.30 (C2, C29), 157.10 (C35, C43), 157.97 (C10, C21), 194.46 (C4, C27). HRMS calcd. for C40H40Na09 [M+Na]+: 687.25700, found: 687.25671.
(2E,28E)-11,14,17,20,36,39,42,45-Octaoxapentacyclo-[41.4.0.0510.021-26.03035]-pentaconta-1(46),2,5(10),6,8,21,23, 25,28,30,32,34,47,49-tetradecaen-2,28-dione (6). A solution of 1,8-bis(2-formylphenoxy)-3,6-dioxanoctane (1b) (0.41 g, 1.30 mmol) in ethanol (10 ml) and a solution of 1,8-bis(2-acetylphenoxy)-3,6-dioxanoctane (2) (0.46 g, 1.30 mmol) in ethanol (10 ml) were added simultaneously to a suspension of K2C03 (5.0 g, 36 mmol) in 30 ml water/ethanol (1:1). The reaction mixture was magnetically stirred at 50 °C for 3 days. The formed precipitate was filtered off, washed with ethanol and chromatographically purified on silica gel (eluating with hexane-ethylacetate, 2:1). Compound (6) was obtained as light-yellow crystals (0.74 g, 1.11 mmol, 88.0 %). Rf=0.51 («-hexane/EtOAc, 1:1). M.p. 174-176 °C. IR (KBr) v cm-1: 29932, 2872, 1655, 1599, 1485. 1H NMR (CDCl3, 500 MHz, 300 K) SH ppm: 3.26, 3.57, 3.64, 3.87, 4.03 and 4.13 (all m, 4H each, respectively, -CH2CH20-); 6.80-7.56 (16H, Harom), 7.36 and 7.89 (both d, 2H each, 0=C-CHtrans=CH, 7=16.0 Hz)™C NMR (CDCl3, 125 MHz, 300 K) SC ppm: 68.33, 68.51, 69.34, 69.73, 70.67, 71.11, 112.46, 112.79, 120.87, 120.92, 124.26, 127.95, 128.73, 130.13, 130.17, 131.45, 132.47, 138.61, 157.17, 157.94, 193.87. MS (m/z): 709.2 [M+H]+. Found (%): C 71.29; H 6.17. C42H44010 requires (%): C 71.17; H 6.26.
In conclusion, two novel crown ethers, tetrakis(benzo)-31-crown-7 ether (5) and tetrakis(benzo)-34-crown-8 ether (6), were successfully synthesized by condensation reaction of podands 1,5-bis(2-formylphenoxy)-3-oxapentane (1a), 1,8-bis(2-formylphenoxy)-3,6-dioxanoctane (1b) and 1,8-bis(2-acetylphenoxy)-3,6-dioxanoctane (2). The molecular structures of non-nitrogenous macroheterocycles were
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established by IR, NMR, and MS. Both of them are interesting as effective complexing ligands in the coordination chemistry.
Acknowledgements. This research is funded by Vietnam Naitonal Foundation for Science and Technology Development (NAFOSTED) under grant number 104.01-2014.39.
References
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4. Truong H.H., Le T.A., Soldatenkov A.T., Golovtsov N.I., Soldatova S.A. Chem. Heterocycl. Compd. 2012, 47, 13171318.
5. Le T.A., Truong H.H., Soldatenkov A.T., Soldatova S.A., Khrustalev V.N. Acta Cryst. E. 2011, E67, 1128-1129.
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Received 31.01.2017 Accepted 07.03.2017
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