122 JOURNAL OF CHEMICAL RESEARCH 2012
4′,5,7-Trihydroxyflavone (1): The mixture of compound 7 (6.2 g,
0.02 mol) and excess pyridine hydrochloride (22.8 g, 0.20 mol) were
heated at 180–190 °C for 6 h under an N2 atmosphere. Then the mix-
ture was cooled to room temperature and ethanol (20 mL) and H2O
(100 mL) were added. The reaction mixture was stirred for 10 min.
The precipitate was filtered off, washed with ethanol and recrystal-
lised from ethanol to give compound 1 (4.9 g); yield 90%, yellow
crystals, m.p. 345–346 °C (lit.3 348–350 °C); IR νmax (KBr/cm−1):
Experimental
All reactions were monitored by TLC, melting points were measured
on a YRT-3 temperature apparatus and are uncorrected. IR spectra
were recorded on Impact 400 FT-IR instrument. NMR spectral data
were recorded on a Bruker DRX 500 NMR spectrometer.
1-(2,4,6-Trihydroxy-phenyl)-ethanone (3): Phloroglucinol 2 (10g,
79.4 m mol) and acetic anhydride 18 mL (19.4 g,190.0 m mol)were
dissolved in ethyl acetate (40 mL), and BF3.Et2O 12 mL (13.8 g, 97.2
m mol) was added dropwise. The reaction mixture was heated at 50 °C
for 10 h. Then, H2O (150 mL) was added and the reaction mixture was
extracted with ethyl acetate, After evaporation of the solvent the raw
material was recrystallised from H2O to give compound 3 (12 g); yield
86%, yellow crystals, m.p. 219–220 °C (lit.13 221 °C); IR (KBr/
cm−1):3201 (OH), 1616 (C=O); 1H NMR (400 MHz, CDCl3):12.23 (s,
2H, OH), 10.38 (s, 1H, OH),5.79 (s, 2H, ArH),2.50 (s, 3H, COCH3).
2-Hydroxy-4,6-dimethoxyacetophenone (4): Compound 3 (16.8 g,
0.1 mol), K2CO3 (28 g, 0.2 mol),and methyl p-toluenesulfonate (40.8
mL, 50.3 g, 0.27 mol) in ethanol (250 mL) were heated at 80 °C for 3
h. Then the mixture was poured into H2O (500 mL), and the precipi-
tate was filtered and recrystallised from methanol to give compound 4
(13.3g); yield 68%, white crystals, m.p. 79–80 °C (lit.14 80–81 °C); IR
1
3527 (OH), 1656 (C=O), 1445 (C=C); H NMR (500 MHz, CDCl3):
12.95 (s, 1H, OH), 10.84 (s, 1H, OH), 10.36 (s, 1H, OH), 7.92 (d, 2H,
J = 8.5 Hz), 6.92 (d, J = 8.5 Hz, 2H), 6.78 (s, 1H), 6.47 (s, 1H), 6.18
(s, 1H).
This study was supported by Natural Science Foundation of
China (No. 21062009), Science Foundation of Department of
Education of Yunnan Province (No. 2011J077), and Analysis
and Testing Foundation of Kunming University of Science and
Technology (No. 2011293).
Received 7 January 2012; accepted 20 January 2012
Paper 1201089 doi:10.3184/174751912X13285269293913
Published online: 22 March 2012
νmax (KBr/cm−1): 3461 (OH),1619(C=O); H NMR (400 MHz, ace-
tone-d6): 13.79 (s, 1H,OH), 6.10 (s, 1H,ArH), 6.07 (s, 1H,ArH), 3.84
(s, 3H,OCH3), 3.79 (s, 3H,OCH3), 2.53 (s, 3H,COCH3).
1
References
2′-Hydroxy-4,4′,6′-trimethoxychalcone (6): Compound 4 (3.0 g,
0.015 mol), anisaldehyde 5 (2.5 g, 0,018 mol), and KOH (12.0 g,
0.21 mol) in methanol (250 mL) were stirred at room temperature
for 72 h. Then the reaction mixture was neutralised to pH 7 with 37%
aqueous HCl. The precipitate was filtered off, washed with water and
recrystallised from ethanol to give compound 6 (3.32 g); yield 87%,
yellow crystals, m.p. 114–115 °C (lit.8 113–114 °C); IR νmax (KBr/
1
A. Trichopoulou, E. Vasilopoulou and P. Hollman, Food Chem., 2000, 70,
319.
2
3
4
U. Justesen and P. Knuthsen, Food Chem., 2001, 73, 245.
T. Liu and Y.Z. Hu, Synth. Commun., 2004, 34, 3209.
P.G. Yeole, S.J. Wadher and N.J. Gaikwad, Int. J. Chem. Sci., 2007, 5,
1133.
5
J.A. Seijas, M.P. Vazquez-Tato and R. Carballido-Reboredo, J. Org. Chem.,
2005, 70, 2855.
cm−1):3648 (OH), 1622 (C=O), 1580 (C=C); H NMR (500 MHz,
1
6
7
G. Wei and B. Yu, Eur. J. Org. Chem., 2008, 18, 3156.
A.Y. Shaw, C.-Y. Chang, H.-H. Liau, P.-J. Lu, H.-L. Chen, C.-N. Yang and
H.-Y. Li, Eur. J. Med. Chem., 2009, 44, 2552
J.A. Smith, D.J. Maloney, S.M. Hecht and D.A. Lannigan, Bioorg. Med.
Chem., 2007, 15, 5018
J. Wang, J. Yang, B. Yang, X. Hu, J.-Q. Sun and T. Yang, J. Chem. Res.,
2010, 34, 717.
CDCl3): 14.42 (s, 1H, OH), 7.83 (s, 1H), 7.80 (s, 1H), 7.57–7.56 (d,
J = 8.3 Hz, 2H), 6.94–6.92 (d, J = 8.3Hz, 2H), 6.11 (s, 1H), 5.96 (s,
1H), 3.91 (s, 3H, OCH3), 3.85 (s, 3H, OCH3), 3.84 (s, 3H, OCH3).
4′,5,7-Trimethoxyflavone (7): Compound 6 (2.5g, 8.0 m mol),
iodine (0.2g, 0.8 m mol) in DMSO (25 mL) were heated at 100 °C for
4 h. Then 0.5% NaHSO3 (50 mL) was added to remove the iodine. The
precipitate was filtered off, washed with water and recrystallised from
ethanol/H2O(1:1) to give compound 7 (2.15 g); yield 86%; off-white
crystals, m.p. 153–154 °C, (lit.8 153–155 °C); IR νmax (KBr/cm−1):
8
9
10 J. Wang, J. Yang, B. Yang, J.-Q. Sun and T. Yang, J. Chem. Res., 2010, 34,
724.
11 J. Wang, J. Yang, R.-G. Zhou, B. Yang and Y.-S. Wu, J. Chem. Res., 2011,
35, 428.
12 J. Wang, J. Yang, R.-G. Zhou, B. Yang and Y.-S. Wu, J. Chem. Res., 2011,
35, 431.
13 G. Bringmann, T.F. Noll, T. Gulder, M. Dreyer, M. Grune and D. Moskau,
J. Org. Chem., 2007, 72, 3247
14 H.-W. Chu, H.-T. Wu and Y.-J. Lee, Tetrahedron, 2004, 60, 2647
1
1647 (C=O), 1607 (C=C); H NMR (400 MHz, MeOD): 7.96–7.94
(d, J = 8.8 Hz, 2H), 7.12–7.10 (d, J = 8.8 Hz, 2H), 6.81 (s, 1H), 6.69
(d, J = 2.0 Hz, 1H), 6.49 (d, J = 2.0 Hz,1H), 4.07 (s, 3H), 4.03 (s, 3H),
4.00 (s, 3H).