Highly Selective Three-Step Synthesis of Rhein in Chloroaluminate Molten Salt
which was isolated as an orange solid (92%, 28.5 mg). The recorded
spectroscopic data for 2 were in accordance with reported analyti-
cal data.[29]
original benzophenone derivatives by DOM; analytical data for all
new amides and carboxylic compounds.
1,5-Dihydroxyanthraquinone-3-carboxylic Acid (11): Yield (13/11,
≈1:4; in AMS): 23.4 mg (83%). Rf = 0.50 (ethyl acetate/methanol/
Acknowledgments
water, 100:13:10). M.p. 278–281 °C. IR (KBr): ν = 3199, 2996,
˜
We are grateful to Les Laboratoires Pierre Fabre and the Centre
National de la Recherche Scientifique (CNRS) for a grant to V.G.
1715, 1686, 1636, 1610, 1578, 1411, 1374, 1280, 1250, 971,
774 cm–1. 1H NMR (600 MHz, [D6]DMSO): δ = 7.40 (d, J =
8.6 Hz, 1 H, ArH), 7.76 (d, J = 1.7 Hz, 1 H, ArH), 7.78 (m, 1 H,
ArH), 7.83 (t, J = 7.9 Hz, 1 H, ArH), 8.12 (d, J = 1.7 Hz, 1 H,
ArH), 12.43 (s, 1 H, ArOH), 12.46 (s, 1 H, ArOH) ppm. 13C NMR
(50 MHz, [D6]DMSO): δ = 115.6, 118.2, 118.5, 119.2, 124.4, 125.0,
132.7, 133.1, 137.5, 138.0, 161.3, 161.7, 165.2, 186.5, 186.8 ppm.
MS (IC, NH3): m/z = 283 [M – H]+.
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1535–1544.
1,7-Dihydroxyanthraquinone-3-carboxylic Acid (13): Yield (13/11,
1
≈1:2; in BMS): 25.1 mg (89%). H NMR (300 MHz, [D6]DMSO):
[5] M. Yaron, I. Shirazi, I. Yaron, Osteoarthritis and Cartilage
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δ = 7.20 (dd, J = 8.7, 2.5 Hz, 1 H, ArH), 7.42 (d, J = 2.5 Hz, 1 H,
ArH), 7.62 (s, 1 H, ArH), 7.98 (d, J = 8.4 Hz, 1 H, ArH), 8.00 (s, [6] Y.-M. Kim, C.-H. Lee, H.-G. Kim, H.-S. Lee, J. Agric. Food
1 H, ArH), 12.16 (s, 1 H, ArOH), 13.6 (s, 1 H, ArOH) ppm. 13C
NMR (50 MHz, [D6]DMSO): δ = 112.1, 119.9, 122.2, 123.2, 125.0,
130.0, 132.4, 133.7, 134.8, 137.9, 161.1, 163.3, 165.4, 179.8,
187.8 ppm. MS (IC, NH3): m/z = 283 [M – H]+.
Chem. 2004, 52, 6096–6100.
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1,7-Dihydroxyanthraquinone (16): Yield (16/17, 4:1; in BMS):
21.5 mg (90%). Rf = 0.38 (ethyl acetate/cyclohexane, 3:7). M.p.
23, 515–518.
[10] G. Di Napoli, EP636602, 636602, 1995.
[11] G. Di Napoli, EP1666446, 2006.
270 °C. IR (KBr): ν = 3085, 2923, 1729, 1667, 1631, 1459, 1465,
˜
[12] J. L. Bloomer, K. W. Stagliano, J. A. Gazzilo, J. Org. Chem.
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1364, 1300, 1328, 1046, 967, 784 cm–1. 1H NMR (600 MHz;
CDCl3/[D4]MeOD, 2:1): δ = 7.17 (dd, J = 8.4, 2.5 Hz, 1 H, ArH),
7.23 (dd, J = 8.1, 1.3 Hz, 1 H, ArH), 7.61 (t, J = 2.5 Hz, 1 H,
ArH), 7.66 (dd, J = 8.1, 7.5 Hz, 1 H, ArH), 7.75 (dd, J = 7.5,
1.3 Hz, 1 H, ArH), 8.12 (t, J = 8.4 Hz, 1 H, ArH), 12.56 (s, 2 H,
ArOH) ppm. 13C NMR (50 MHz, CDCl3/[D4]MeOD, 2:1): δ =
112.1, 116.1, 118.9, 122.1, 123.5, 125.2, 130.0, 133.4, 134.9, 137.2,
161.4, 163.2, 180.5, 188.3 ppm. MS (IC, NH3): m/z = 239
[M – H]+.
1,6-Dihydroxyanthraquinone (19): Yield (in AMS): 20.4 mg (85%).
Rf = 0.38 (ethyl acetate/cyclohexane, 3:7). M.p. 273–275 °C. IR
[18] V. Gonnot, S. Tisserand, M. Nicolas, R. Baati, C. Mioskowski,
Tetrahedron Lett. 2007, 48, 7117–7119.
(KBr): ν = 3091, 2976, 1724, 1667, 1650, 1594, 1380, 1332, 1255, [19] M. Uchiyama, H. Naka, Y. Matsumoto, T. Ohwada, J. Am.
˜
1187, 1037, 773 cm–1. 1H NMR (300 MHz; CDCl3/[D4]MeOD,
2:1): δ = 7.18 (dd, J = 8.6, 2.6 Hz, 1 H, ArH), 7.26 (d, J = 8.3 Hz,
1 H, ArH), 7.55 (t, J = 2.6 Hz, 1 H, ArH), 7.60 (t, J = 8.3, J =
7.5 Hz, 1 H, ArH), 7.76 (d, J = 7.5 Hz, 1 H, ArH), 8.18 (t, J =
8.6 Hz, 1 H, ArH), 12.82 (s, 2 H, ArOH) ppm. 13C NMR (50 MHz;
CDCl3/[D4]MeOD, 2:1): δ = 113.0, 119.2, 121.4, 124.2, 124.5,
129.7, 133.6, 135.7, 135.9, 161.9, 163.6, 183.0, 187.7 ppm. MS (IC,
NH3): m/z = 241 [M + H]+.
Chem. Soc. 2004, 126, 10526–10527.
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1979, vol. VII, 3e.
1-Methyl-8-hydroxyanthraquinone (28): Yield (28/29, ≈47:53; in
AMS): 16.8 mg (78%). Rf = 0.85 (ethyl acetate/cyclohexane, 1:1).
[24] J. A. Boon, J. A. Levisky, J. L. Pflug, J. S. Wilkes, J. Org. Chem.
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2614.
IR (KBr): ν = 3079, 2989, 2932, 1720, 1689, 1646, 1622, 1463, 1299,
˜
917, 760, 739 cm–1. 1H NMR (300 MHz, CDCl3): δ = 2.88 (s, 3 H,
ArMe), 7.29 (m, 1 H, ArH), 7.58–7.69 (m, 3 H, ArH), 7.80 (d, J =
7.5 Hz, 1 H, ArH), 8.24 (d, J = 7.2 Hz, 1 H, ArH), 12.87 (s, 1 H,
ArOH) ppm. 13C NMR (75 MHz, CDCl3): δ = 24.0, 117.1, 119.0,
124.6, 126.4, 132.0, 133.0, 133.9, 135.2, 136.2, 138.6, 142.6, 162.5,
183.1, 191.3 ppm. MS (IC, NH3): m/z = 238 [M]+.
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3772–3789.
[27] T. Welton, Chem. Rev. 1999, 99, 2071–2083.
[28] Novel anthraquinone structures 11, 13, 16, 19, and 28 were
unambiguously characterized and assigned by 1D and 2D
NMR spectroscopy and by additional nOe experiments. Com-
pounds 16 and 18 were characterized by comparison of their
analytical data with that of authentic commercial samples.
[29] X. Zhou, B. Song, L. Jin, D. Hu, C. Diao, G. Xu, Z. Zou, S.
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1-Methyl-8-hydroxyanthraquinone (29): Yield (29/28, ≈57:43; in
1
AMS): 16.9 mg (78%). H NMR (300 MHz, CDCl3): δ = 2.66 (s,
3 H, Me), 7.29 (m, 1 H, ArH), 7.58–7.69 (m, 4 H, ArH), 8.06 (d,
J = 7.5 Hz, 1 H, ArH), 8.24 (d, J = 7.2 Hz, 1 H, ArH), 12.55 (s, 1
H, ArOH) ppm. MS (IC, NH3): m/z = 238 [M]+.
Supporting Information (see footnote on the first page of this arti-
cle): Details and experimental procedures for the preparation of
Eur. J. Org. Chem. 2009, 6205–6210
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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