932
A. M. CARDOSO ET AL .
Hz, H-6), 7.04 (1H, d, J \ 8.1 Hz, H-8), 7.33È7.47 (5H,
m, H-3@,3A,4@,5@,5A), 7.56 (1H, t, J \ 7.4 Hz, H-4A), 7.62
(1H, t, J \ 8.1 Hz, H-7), 7.64 (2H, d, J \ 7.9 Hz, H-2@,
6@), 7.93 (2H, d, J \ 7.9 Hz, H-2A,6A), 12.18 (1H, s, OH-5).
5-Hydroxy-4@-methoxyÑavone (3c). M.p. 154È156 ¡C
(lit.20 154È156 ¡C). 1H NMR (CDCl ): 3.88 (3H, OCH ,
3
3
s), 6.62 (1H, s, H-3), 6.78 (1H, dd, J \ 8.4 and 0.9 Hz,
H-6), 6.95 (1H, dd, J \ 8.4 and 0.9 Hz, H-8), 7.00 (2H, d,
J \ 9.1 Hz, H-3@,5@), 7.51 (1H, t, J \ 8.4 Hz, H-7), 7.84
(2H, d, J \ 9.1 Hz, H-2@,6@), 12.69 (1H, s, OH-5). 13C
NMR (CDCl ): 55.5 (OCH ), 104.5 (C-3), 106.9 (C-8),
13C NMR (CDCl ): 107.2 (C-8), 110.1 (C-10), 112.0 (C-
3
6), 121.0 (C-3), 128.6 (C-2@,6@), 128.9 (C-3@,3A,5@,5A), 129.4
(C-2A,6A), 131.2 (C-1@), 131.9 (C-4@), 134.1 (C-4A), 136.8 (C-
7), 136.8 (C-1A), 156.2 (C-9), 160.9 (C-5), 163.7 (C-2),
181.6 (C-4), 192.5 (C-7A).
3
3
110.7 (C-10), 111.3 (C-6), 114.5 (C-3@,5@), 123.4 (C-1@),
128.1 (C-2@,6@), 135.1 (C-7), 156.3 (C-9), 160.8 (C-5), 162.7
(C-4@), 164.5 (C-2), 183.4 (C-4).
4@-Chloro-3-(4A-chlorobenzoyl)-5-hydroxyÑavone
(1b).
2@,6@-Dichloro-5-hydroxyÑavone (3d). M.p. 142È146 ¡C.
M.p. 163È165 ¡C. 1H NMR (CDCl ): 6.87 (1H, d,
3
1H NMR (CDCl ): 6.39 (1H, s, H-3), 6.86 (1H, dd,
J \ 8.3 Hz, H-6), 7.03 (1H, d, J \ 8.3 Hz, H-8), 7.36
3
J \ 8.3 Hz, H-6), 6.94 (1H, dd, J \ 8.3 Hz, H-8), 7.42È
(2H, d, J \ 8.6 Hz, H-3@,5@), 7.42 (2H, d, J \ 8.6 Hz,
H-3A,5A), 7.56 (2H, d, J \ 8.6 Hz, H-2@,6@), 7.63 (1H, t,
J \ 8.3 Hz, H-7), 7.86 (2H, d, J \ 8.6 Hz, H-2A,6A), 12.04
7.48 (3H, m, H-3@,4@5@), 7.53 (1H, t, J \ 8.3 Hz, H-7),
12.42 (1H, s, OH-5).
(1H, s, OH-5). 13C NMR (CDCl ):107.1 (C-8), 110.2 (C-
3
7-Hydroxy-5,4º-dimethoxy-3-(4/-methoxybenzoyl)Ñavone (1e).
Treatment of 2@,4@,6@-trihydroxyacetophenone with p-
methoxybenzoyl chloride in pyridine for 2 h provide
2@,4@,6@-tri(p-methoxybenzoyloxy)acetophenone. BakerÈ
Venkataraman rearrangement22h24 of this acetophe-
none with anhydrous potassium carbonate in pyridine
at reÑux for 3 h gave 2,2-di(p-methoxybenzoyl)-4@-(p-
methoxybenzoyloxy)-2@,6@-dihydroxyacetophenone (and
corresponding enolic forms) intermediates.24 The cycli-
zation of the latter compounds, without further puriÐ-
cation, was performed with sulphuric acid in acetic acid.
Usual work-up followed by puriÐcation of the crude
product by column chromatography, using chloroform
as solvent and eluent, a†orded 3-(4A-methoxybenzoyl)-5,
7-dihydroxyÑavone (50%), which was crystallized from
ethanol. This compound was benzylated with benzyl
chloride, potassium carbonate and potassium iodide in
acetone at reÑux for 12 h. After Ðltration of inorganic
salts, the crude product was puriÐed by thin-layer
chromatography, using chloroform as solvent and
eluent. Crystallization of the residue from ethanol
gave 7-benzylozy-5-hydroxy-4@-methoxy-3-(4A-methoxy-
benzoyl)Ñavone (73%). This Ñavone was methylated
with methyl sulphate and sodium hydride in tetra-
hydrofuran at reÑux for 3 h. Usual work-up followed by
column chromatographic puriÐcation, using chloroform
as solvent and eluent, yielded 7-benzylozy-5,4@-
dimethoxy-3-(4A-methoxybenzoyl)Ñavone (70%), which
was crystallized from ethanol. The hydrogenolysis of the
7-benzylic group of this Ñavone was carried out with
Pd/C and ammonium formate in methanol at reÑux for
3 h. Filtration of the reaction mixture through Celite
followed by crystallization of the crude product from
ethanol gave 7-hydroxy-5,4@-dimethoxy-3-(4A-methoxy-
benzoyl)Ñavone (1e) (60%).
10), 112.3 (C-6), 121.0 (C-3), 129.4 (C-2@,6@), 129.4 (C-2A,
6A), 129.6 (C-1A), 129.9 (C-3A,5A), 130.7 (C-3@,5@), 135.2 (C-
1@), 136.4 (C-7), 138.6 (C-4A), 140.9 (C-4@), 156.2 (C-9),
161.1 (C-5), 162.6 (C-2), 181.4 (C-4), 191.0 (C-7A).
5-Hydroxy-4@-methoxy-3-(4A-methoxybenzoyl) Ñavone
(1c). M.p. 172È175 ¡C (lit.20 177È178 ¡C). 1H NMR
(CDCl ): 3.79 and 3.84 (2 ] OCH , 2 s), 6.83 (1H, d,
3
3
J \ 8.1 Hz, H-6), 6.86 (2H, d, J \ 8.9 Hz, H-3@,5@), 6.90
(2H, d, J \ 9.0 Hz, H-3A,5A), 7.01 (1H, d, J \ 8.1 Hz,
H-8), 7.58 (1H, t, J \ 8.1 Hz, H-7), 7.64 (2H, d, J \ 8.9
Hz, H-2@,6@), 7.92 (2H, d, J \ 9.0 Hz, H-2A,6A), 12.31
(1H, s, OH-5). 13C NMR (CDCl ): 55.4 and 55.5 (2
3
] OCH ), 107.0 (C-8), 110.0 (C-10), 111.7 (C-6), 114.2
3
(C-3A,5A), 114.3 (C-3@,5@), 120.0 (C-3), 123.4 (C-1@), 130.0
(C-1A), 130.4 (C-2@,6@), 131.9 (C-2A,6A), 135.8 (C-7), 156.1
(C-9), 160.6 (C-5), 162.4 (C-4@), 163.0 (C-2), 164.3 (C-4A),
181.6 (C-4), 191.4 (C-7A).
2@, 6@-Dichloro-3-(2A, 6A-dichlorobenzoyl)-5-hydroxyÑavone
(1d). M.p. 178È179 ¡C. 1H NMR (CDCl ): 6.88 (1H, dd,
3
J \ 8.3 and 0.6 Hz, H-6), 6.96 (1H, dd, J \ 8.3 and 0.6
Hz, H-8), 7.24È7.28 (3H, m, H-3@,4@,5@), 7.40È7.42 (3H, m,
H-3A,4A,5A), 7.60 (1H, t, J \ 8.3 Hz, H-7), 12.08 (1H, s,
OH-5). 13C NMR (CDCl ): 107.4 (C-8), 110.8 (C-10),
3
113.0 (C-6), 120.2 (C-3), 127.9 (C-3@,5@), 128.0 (C-3A,5A),
130.1 (C-4@), 131.2 (C-2@,6@), 131.7 (C-4A), 134.0 (C-1@),
134.0 (2A,6A), 136.5 (C-7), 139.5 (C-1A), 155.9 (C-9), 161.3
(C-5), 167.4 (C-2), 180.7 (C-4), 186.5 (C-7A).
5-HydroxyÑavone (3a). M.p. 153È154 ¡C (lit.20 158È
159 ¡C). 1H NMR (CDCl ): 6.76 (1H, s, H-3), 6.83 (1H,
3
d, J \ 8.2 Hz, H-6), 7.02 (1H, d, J \ 8.4 Hz, H-8), 7.53È
7.59 (4H, m, H-3@,4@,5@,7), 7.93 (2H, dd, J \ 7.8 and 1.8
Hz, H-2@,6@), 12.59 (1H, s, OH-5). 13C NMR (CDCl ):
3
106.1 (C-3), 107.1 (C-8), 110.9 (C-10), 111.5 (C-6), 126.5
7-Hydroxy-5, 4@-dimethoxy-3-(4A-methoxybenzoyl)Ñavone
(C-2@,6@), 129.2 (C-3@,5@), 131.3 (C-1@), 132.1 (C-4@), 135.4
(1e). M.p. 272È274 ¡C. 1H NMR ((CD ) SO): 3.75, 3.77
(C-7), 156.5 (C-9), 160.8 (C-5), 164.6 (C-2), 183.6 (C-4).
3 2
and 3.81 (3 ] OCH , 3 s), 6.45 (1H, s, H-6), 6.56 (1H, s,
3
4@-Chloro-5-hydroxyÑavone (3b). M.p. 186È187 ¡C. 1H
H-8), 6.97 (2H, d, J \ 8.5 Hz, H-3@,5@), 6.98 (2H, d,
NMR (CDCl ): 6.67 (1H, s, H-3), 6.80 (1H, dd, J \ 8.3
J \ 8.4 Hz, H-3A,5A), 7.52 (2H, d, J \ 8.5 Hz, H-2@,6@),
7.83 (2H, d, J \ 8.4 Hz, H-2A,6A), 10.97 (1H, s broad,
3
and 0.8 Hz, H-6), 6.97 (1H, dd, J \ 8.3 and 0.8 Hz, H-8),
7.49 (2H, d, J \ 8.7 Hz, H-3@,5@), 7.53 (1H, t, J \ 8.3 Hz,
H-7), 7.82 (2H, d, J \ 8.7 Hz, H-2@,6@), 12.46 (1H, s,
OH-7). 13C NMR ((CD ) SO): 55.4, 55.6 and 55.9
3 2
(3 ] OCH ), 95.2 (C-8), 96.7 (C-6), 106.3 (C-10), 114.2
3
OH-5). 13C NMR (CDCl ): 106.2 (C-3), 106.5 (C-8),
(C-3A,5A), 114.3 (C-3@,5@), 121.8 (C-3), 123.4 (C-1@), 129.7
3
110.9 (C-10), 111.7 (C-6), 127.7 (C-2@,6@), 129.5 (C-3@,5@),
(C-2@,6@), 130.0 (C-1A), 131.4 (C-2A,6A), 157.7 (C-2), 159.0
(C-9), 160.9 (C-5), 161.3 (C-4@), 163.1 (C-7), 163.6 (C-4A),
174.2 (C-4), 192.4 (C-7A).
129.8 (C-1@), 135.5 (C-7), 138.4 (C-4@), 156.4 (C-9), 161.0
(C-5), 163.4 (C-2), 183.4 (C-4).
( 1997 by John Wiley & Sons, Ltd.
JOURNAL OF MASS SPECTROMETRY, VOL. 32, 930È939 (1997)