EXPERIMENTAL
Preparation of 4,6-pyrimidyl di(2-bromo-4-chlorobenzoate) (2b)
2-Bromo-4-chlorobenzoyl chloride (2.54 g, 10.0 mmol) was added to a suspended solution of 4,6-dihydroxypyrimidine (560 mg, 5.0 mmol) and triethylamine (1.40 mL, 10.0 mmol) in methylene chloride (40 mL) at room temperature. After stirring for 3 h, methylene chloride was evaporated in vacuo. The mixture was dissolved in anhydrous THF and triethylamine hydrochloride was filtered off. The residue was recrystallized twice in 75% EtOAc/n-hexane to give 2b (2.32 g, 85%). mp 134−136 ℃; 1H NMR (300 MHz, CDCl3) δ 8.99 (s, 1H), 8.11 (d, J = 8.5 Hz, 2H), 7.80 (d, J = 0.8 Hz, 2H), 7.47 (dd, J1 = 8.5 Hz, J2 = 0.8 Hz, 2H), 7.40 (s, 1H); 13C NMR (75 MHz, CDCl3) δ 166.6, 161.1, 159.2, 140.4, 135.0, 133.6, 128.0, 127.1, 124.3, 105.4; FTIR (KBr) 1762 (C=O) cm−1.
Preparation of 1-(2-bromo-4-chlorophenyl)-3-(4-methoxyphenyl)-2-propyn-1-one (3bj)
4-Methoxyphenylethynylmagnesium bromide, generated from 4-methoxyphenylacetylene (529 mg, 4.0 mmol) and ethylmagnesium bromide (1.0 M, 4.0 mL, 4.0 mmol) in THF (10 mL), was slowly added to a solution of 2b (1.09 g, 2.0 mmol) in THF (15 mL) at 0 ℃ under argon atmosphere. The mixture was stirred for 0.5 h at 0 ℃ and then quenched with saturated NH4Cl solution (5 mL). After evaporating THF, the mixture was poured into saturated NH4Cl solution (30 mL) and extracted with methylene chloride (3×20 mL). The combined organic phases were dried over MgSO4, filtered, and concentrated in vacuo. The residue was recrystallized twice in 10% EtOAc/n-hexane to give 3bj (1.16 g, 83%). mp 131−133 ℃; 1H NMR (300 MHz, CDCl3) δ 8.01 (d, J = 8.4 Hz, 1H), 7.72 (d, J = 1.8 Hz, 1H), 7.60 (d, J = 8.9 Hz, 2H), 7.43 (dd, J1 = 8.4 Hz, J2 = 1.9 Hz, 1H), 6.93 (d, J = 8.9 Hz, 2H), 3.86 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 176.4, 162.0, 138.9, 136.1, 135.3, 134.6, 133.5, 127.7, 121.9, 114.5, 111.5, 96.1, 87.9, 55.5; FTIR (KBr) 2196 (C≡C), 1641 (C=O) cm−1; Ms m/z (%) 352 (M++4, 21), 350 (M++2, 85), 348 (M+, 67), 324 (13), 322 (54), 320 (42), 159 (100).
Preparation of 7-chloro-4'-methoxythioflavone (5bj)
A solution of 3bj (1.05 g, 3.0 mmol) in EtOH (20 mL) was added to a suspended solution of sodium hydrosulfide hydrate (60% dispersion in mineral oil, 336 mg, 3.6 mmol) in EtOH (15 mL) at room temperature. Stirring was continued at this temperature for 0.5 h and the resulting reddish solution was refluxed for 1.5 h more. After evaporating EtOH, the mixture was poured into saturated NH4Cl solution (30 mL) and extracted with methylene chloride (3×20 mL). The combined organic phases were dried over MgSO4, filtered, and concentrated in vacuo. The residue was recrystallized twice in 10% EtOAc/n-hexane to give 5bj (772 mg, 85%). mp 173−174 ℃; 1H NMR (300 MHz, CDCl3) δ 8.45 (d, J = 8.7 Hz, 1H), 7.62 (d, J = 1.9 Hz, 1H), 7.63 (d, J = 8.9 Hz, 2H), 7.47 (dd, J1 = 8.6 Hz, J2 = 2.0 Hz, 1H), 7.16 (s, 1H), 7.01 (d, J = 8.9 Hz, 2H), 3.88 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 180.1, 162.0, 152.5, 138.9, 138.2, 130.1, 129.3, 128.4, 128.3 (overlapped), 125.7, 122.2, 114.7, 55.5; FTIR (KBr) 1625 (C=O) cm−1; Ms m/z (%) 304 (M++2, 40), 302 (M+, 100), 276 (15), 274 (47), 261 (11), 259 (34), 132 (41).
5af, 5ag, 5aj, and 7: All products were identified by means of mp, 1H/13C NMR, FTIR, and mass spectrometry and consistent with the previous results.18a,c
7-Chloro-3-thienyl-4H-1-benzothiopyran-4-one (5bl): mp 150−151 ℃; 1H NMR (300 MHz, CDCl3) δ 8.44 (d, J = 8.6 Hz, 1H), 7.77 (dd, J1 = 2.9 Hz, J2 = 1.4 Hz, 1H), 7.61 (d, J = 1.9 Hz, 1H), 7.45−7.50 (m, 2H), 7.42 (dd, J1 = 5.1 Hz, J2 = 1.3 Hz, 1H), 7.21 (s, 1H); 13C NMR (75 MHz, CDCl3) δ 180.2, 146.5, 138.5, 138.4, 137.3, 130.2, 129.4, 128.4, 127.8, 125.6, 125.3, 125.2, 122.1; FTIR (KBr) 1615 (C=O) cm−1; Ms m/z (%) 280 (M++2, 41), 278 (M+, 98), 252 (41), 250 (100), 170 (47).
7,4'-Dimethylthioflavone (5ch): mp 129 ℃; 1H NMR (300 MHz, CDCl3) δ 8.42 (d, J = 8.3 Hz, 1H), 7.58 (d, J = 8.2 Hz, 2H), 7.43 (s, 1H), 7.34 (d, J = 8.3 Hz, 1H), 7.29 (d, J = 8.0 Hz, 2H), 7.19 (s, 1H), 2.47 (s, 3H), 2.42 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 180.8, 152.7, 142.4, 141.2, 137.9, 133.8, 129.9, 129.2, 128.8, 128.5, 126.8, 126.2, 122.9, 21.6, 21.4; FTIR (KBr) 1638 (C=O) cm−1; Ms m/z (%) 266 (M+, 100), 238 (86), 150 (34), 121 (21).
7-Methyl-2'-methoxythioflavone (5ci): mp 118−119 ℃; 1H NMR (300 MHz, CDCl3) δ 8.44 (d, J = 8.3 Hz, 1H), 7.42−7.46 (m, 2H), 7.40 (s, 1H), 7.33 (d, J = 8.3 Hz, 1H), 7.12 (s, 1H), 7.06 (d, J = 7.6 Hz, 1H), 7.01 (d, J = 8.4 Hz, 1H), 3.85 (s, 3H), 2.46 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 180.7, 156.5, 149.9, 142.2, 138.9, 131.5, 130.3, 129.1, 128.7, 128.4, 126.8, 125.9, 125.6, 120.9, 111.7, 55.8, 21.6; FTIR (KBr) 1620 (C=O) cm−1; Ms m/z (%) 282 (M+, 100), 151 (72), 121 (25).
7-Methyl-3-pyridyl-4H-1-benzothiopyran-4-one (5cm): mp 154−155 ℃; 1H NMR (300 MHz, CDCl3) δ 8.94 (d, J = 1.9 Hz, 1H), 8.75 (dd, J1 = 4.8 Hz, J2 = 1.3 Hz, 1H), 8.43 (d, J = 8.3 Hz, 1H), 7.95−7.99 (m, 1H), 7.42−7.46 (m, 1H), 7.46 (s, 1H), 7.38 (d, J = 8.3 Hz, 1H), 7.19 (s, 1H), 2.50 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 180.4, 151.6, 149.0, 147.7, 142.9, 137.3, 134.3, 132.7, 129.7, 128.6, 126.2, 124.3, 123.8, 123.2, 21.6; FTIR (KBr) 1636 (C=O) cm−1; Ms m/z (%) 253 (M+, 100), 225 (74), 150 (29), 121 (24).
6-Methoxy-3'-chlorothioflavone (5dg): mp 189−190 ℃; 1H NMR (300 MHz, CDCl3) δ 7.98 (d, J = 2.7 Hz, 1H), 7.68 (s, 1H), 7.55−7.59 (m, 2H), 7.41-7.50 (m, 2H), 7.25−7.29 (m, 1H), 7.22 (s, 1H), 3.95 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 180.4, 159.7, 151.2, 138.4, 135.3, 132.3, 130.7, 130.5, 129.4, 127.8, 127.1, 125.2, 123.0, 122.4, 108.8, 55.8; FTIR (KBr) 1625 (C=O) cm-1; Ms m/z (%) 304 (M++2, 39), 302 (M+, 100), 272 (28), 123 (20).
6,3',5'-Trimethoxythioflavone (5dk): mp 154−155 ℃; 1H NMR (300 MHz, CDCl3) δ 7.98 (d, J = 2.8 Hz, 1H), 7.56 (d, J = 8.8 Hz, 1H), 7.24 (s, 1H), 7.26 (dd, J1 = 8.5 Hz, J2 = 2.1 Hz, 1H), 6.82 (d, J = 2.2 Hz, 2H), 6.58 (t, J = 2.2 Hz, 1H), 3.94 (s, 3H), 3.85 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 180.5, 161.3, 159.6, 153.0, 138.6, 132.4, 129.7, 127.8, 122.6, 122.2, 108.9, 105.1, 102.7, 55.7, 55.6; FTIR (KBr) 1626 (C=O) cm−1; Ms m/z (%) 328 (M+, 100), 298 (33), 123 (12).
References
- Nakazumi, H.; Ueyama, T.; Kitao, T. J. Heterocycl. Chem. 1984, 21, 193. https://doi.org/10.1002/jhet.5570210138
- Nakazumi, H.; Kobara, Y.; Kitao, T. J. Heterocycl. Chem. 1992, 29, 135. https://doi.org/10.1002/jhet.5570290124
- Choi, E. J.; Lee, J. I.; Kim, G.-H. Int. J. Mol. Med. 2012, 29, 252.
- (a) Nussbaumer, P.; Winiski, A. P.; Billich, A. J. Med. Chem. 2003, 46, 5091. https://doi.org/10.1021/jm030926s
- (b) Horvath, A.; Nussbaumer, P.; Wolff, B.; Billich, A. J. Med. Chem. 2004, 47, 4268. https://doi.org/10.1021/jm0407916
- (a) Holshouser, M. H.; Loeffer, L. J.; Hall, I. H. J. Med. Chem. 1981, 24, 853. https://doi.org/10.1021/jm00139a017
- (b) Wang, H.-K.; Bastow, K. F.; Cosentino, L. M.; Lee, K.-H. J. Med. Chem. 1996, 39, 1975. https://doi.org/10.1021/jm960008c
- Dhanak, D.; Keenan, R. M.; Burton, G.; Kaura, A.; Darcy, M. G.; Shah, D. H.; Ridgers, L. H.; Breen, A.; Lavery, P.; Tew, D. G.; West, A. Bioorg. Med. Chem. Lett. 1998, 8, 3677. https://doi.org/10.1016/S0960-894X(98)00666-0
- Patonay, T.; Adam, W.; Levai, A.; Kover, P.; Nemeth, M.; Peters, E.-M.; Peters, K. J. Org. Chem. 2001, 66, 2275. https://doi.org/10.1021/jo001469f
- (a) Nakazumi, H.; Watanabe, S.; Kitaguchi, T.; Kitao, T. Bull. Chem. Soc. Jpn. 1990, 63, 847. https://doi.org/10.1246/bcsj.63.847
- (b) Dekermendjian, K.; Kahnberg, P.; Witt, M.-R.; Sterner, O.; Nielsen, M.; Liljefors, T. J. Med. Chem. 1999, 42, 4343. https://doi.org/10.1021/jm991010h
- (c) Sabatini, S.; Gosetto, F.; Manfroni, G.; Tabarrini, O.; Kaatz, G. W.; Patel, D.; Cecchetti, V. J. Med. Chem. 2011, 54, 5722. https://doi.org/10.1021/jm200370y
- Wadworth, D. H.; Detty, M. R. J. Org. Chem. 1980, 45, 4611. https://doi.org/10.1021/jo01311a013
- Kobayashi, K.; Kobayashi, A.; Ezaki, K. Heterocycles 2012, 85, 1997. https://doi.org/10.3987/COM-12-12508
- (a) Taylor, A. W.; Dean, D. K. Tetrahedron Lett. 1988, 29, 1845. https://doi.org/10.1016/S0040-4039(00)82060-2
- (b) Kataoka, T.; Watanabe, S.; Mori, E.; Kadomoto, R.; Tanimura, S.; Kohno, M. Bioorg. Med. Chem. 2004, 12, 2397. https://doi.org/10.1016/j.bmc.2004.02.002
- (a) French, K. L.; Angel, A. J.; Williams, A. R.; Hurst, D. R.; Beam, C. F. J. Heterocycl. Chem. 1998, 35, 45. https://doi.org/10.1002/jhet.5570350109
- (b) Angel, A. J.; Finefrock, A. E.; French, K. L.; Hurst, D. R.; Williams, A. R.; Rampey, M. E.; Studer-Martinez, S. L.; Beam, C. F. Can. J. Chem. 1999, 77, 94. https://doi.org/10.1139/v98-216
- Metz, C. R.; Knight, J. D.; Pastine, S. J.; Pennington, W. T.; Beam, C. F. J. Chem. Crystallogr. 2010, 40, 536. https://doi.org/10.1007/s10870-010-9692-z
- (a) Kumar, P.; Rao, A. T.; Pandey, B. J. Chem. Soc., Chem. Commun. 1992, 1580.
- (b) Kumar, P.; Rao, A. T.; Pandey, B. Synth. Commun. 1994, 24, 3297. https://doi.org/10.1080/00397919408010253
- Kumar, P.; Bodas, M. S. Tetrahedron 2001, 57, 9755. https://doi.org/10.1016/S0040-4020(01)00977-2
- Fuchs, F. C.; Eller, G. A.; Holzer, W. Molecules 2009, 14, 3814. https://doi.org/10.3390/molecules14093814
- (a) Willy, B.; Muller, T. J. J. Synlett 2009, 1255.
- (b) Willy, B.; Frank, W.; Muller, T. J. J. Org. Biomol. Chem. 2010, 8, 90. https://doi.org/10.1039/B917627F
- (a) Lee, J. I. Bull. Korean Chem. Soc. 2009, 30, 710. https://doi.org/10.5012/bkcs.2009.30.3.710
- (b) Lee, J. I.; Kim, M. J. Bull. Korean Chem. Soc. 2011, 32, 1383. https://doi.org/10.5012/bkcs.2011.32.4.1383
- (c) Lee, J. I. Bull. Korean Chem. Soc. 2008, 29, 1263. https://doi.org/10.5012/bkcs.2008.29.6.1263
- Jang, E. J.; Seok, Y. M.; Lee, J. I.; Cho, H. M.; Sohn, U. D.; Kim, I. K. Naunyn-Schmiedeberg’s Arch. Pharmacol. 2013, 386, 339. https://doi.org/10.1007/s00210-012-0818-z
Cited by
- A rapid entry into thioflavanones via conjugate additions of diarylcuprates to thiochromones vol.73, pp.39, 2017, https://doi.org/10.1016/j.tet.2017.08.012
- Competitive cascade cyclization of 2′-tosyloxychalcones: An easy access to thioflavones and thioaurones vol.50, pp.15, 2015, https://doi.org/10.1080/00397911.2020.1775852
- New Synthesis of Thioflavones by the Regioselective Cyclization of 1-(2-Benzylthio)phenyl-3-phenylprop-2-yn-1-ones Using Hydrobromic Acid vol.64, pp.4, 2015, https://doi.org/10.5012/jkcs.2020.64.4.239
- Synthetic Approaches to 2‐ALKYLTHIOCHROMAN ‐4‐ones and Thioflavanones vol.42, pp.6, 2015, https://doi.org/10.1002/bkcs.12272
- A review of the syntheses of (thio)flavones, 4‐QUINOLONES , (thio)aurones, and azaaurones from 2′‐substituted alkynones vol.42, pp.12, 2015, https://doi.org/10.1002/bkcs.12412