Synthesis of flavonoid 7-O-β-D-glycosides by phase transfer catalysis

Article abstract of DOI:10.3184/030823409X431346

Six flavonoid 7-O-β-D-glycosides 1a-3a and 1b-3b were synthesised from the flavones 7a and 7b by glycosidation and deacetylation with the corresponding a-acetylglycosyl bromides. 7a and 7b were prepared in high yield by an improved Baker-Venkataraman rearrangement using 2, 4- dihydro×yacetophenone as starting material and tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. The glycosidation procedure was modified by using anhydrous K2CO3 in a solvent mixture of DMF/acetone (3:2v/v) and TBAB as a phase transfer catalyst.

Full text of DOI:10.3184/030823409X431346

JOURNAL OF CHEMICAL RESEARCH 2009
MARCH, 195-197
RESEARCH PAPER 195
Synthesis of flavonoid 7-D-(3-D-glycosides by phase transfer catalysis
Zheng Wu, Ling Jiang, He Chen and Qiu-an Wang*
College of Chemistry and Chemical Engineering,
Hunan University, Changsha 410082, P.R. China
Six flavonoid 7-0-13-D-glycosides 1a-3a and 1b-3b were synthesised from the flavones 7a and 7b by glycosidation and
deacetylation with the corresponding a-acetylglycosyl bromides. 7a and 7b were prepared in high yield by an improved
Baker-Venkataraman rearrangement using 2, 4-dihydroxyacetophenone
as starting material and tetrabutylammonium
bromide (TBAB) as a phase transfer catalyst. The glycosidation procedure was modified by using anhydrous K2C03 in
a solvent mixture of DMF/acetone (3: 2v/v) and TBAB as a phase transfer catalyst.
Keywords: flavonoid 7-0-13-D-glycosides, phase transfer catalysis, glycosidation, synthesis
Flavonoids are
a
large class of polyphenolic secondary
an efficient procedure for the synthesis of flavonoid 7-0-13-D-
glycosides by phase transfer catalysis.
metabolites which are abundant in plants and in human diet.!
Most flavonoids occur in nature as glycosides in which at
least one of the OH groups are glycosylated by mono- to
tetrasaccharides involving neutral sugars such as D-glucose,
D-galactose, L-rhanmose and D-xylose. Flavonoids and
flavonoid glycosides possess a wide range of pharmacological
properties including anti-cancer, anti-viral, anti-inflammatory,
anti-cardiovascular action and radical- scavenging properties. 2-5
These may be the consequence of their antioxidant properties
and their affinity for proteins including enzymes.
Among the over 500 flavone O-glycosides and over 100
isoflavone O-glycosides so far recorded, the majority are 7-0-
glycosides and among the over 1000 flavonol glycosides
about 40% contain a 7-O-glycosidic linkage. In contrast to the
wide occurrence and importance of flavonoid O-glycosides,
synthetic studies of these compounds are only sporadic and
mostly rely on conventional transformations.6 Here we report
Scheme 1 outlines the synthesis of six flavonoid 7-0-13-D-
glycosides la-3a and Ib-3b from 7-hydroxyflavones 7a and
7b, which were readily prepared from commercially available
2,4-dihydroxyacetophenone. Currently there are a number
of methods available to synthesise flavones, including the
Allan-Robinson synthesis, the Baker-Venkataraman method
synthesis from chalcones, and synthesis via an intramolecular
Wittig strategy. At the outset, it appeared that the Baker-
Venkataraman approach, shown in Scheme 1, would be the
most convenient route to the synthesis of7a and 7b.
In this process, 2, 4-dihydroxyacetophenone was first
converted into its benzoyl ester which was then isolated and
treated with a base, usually potassium hydroxide or potassium
carbonate, to effect an intramolecular Claisen condensation,
forming a 1,3-diketone. Acid treatment induces a dehydrative
cyclisation of the 1,3-diketone to the desired flavone 7a and
H,sO.
HO
"'
#
0
"-
I
H0Y'r0H
K2CO "TBAB
CH,CO O H
I
I
~CH3
+
acetone, reflux
vrrR
o
o
7a R=H
7bR=CI
5a R=H
5b R=CI
6a R=H R,=PhCO
6b R=CIR,=4-CIPhCO
R
~O AC
a-acetylbrom oglucoseK,2CO , AcO O
0
0
____
H~;40~O ~R
7a or7b
y
Ac
DMF, acetone,TBAB,r,1.
O Ac
r,1
OH L l) ,
o
8b R=CI
o
8a R=H
1a R=H
1bR=CI
~C
o
R
~~
HO HO
7a or7b a-acetylbromogalactose, K2C03
DMF, acetone, TBAB, r.t.
AcO AcO
O ~O ~
NH,H20,CH,O H
0
~O ~R
~
- - - r , t - ,
- - - -
0
CV "-
o
0
ACO ~faF~
#:::~'
R
~
~~,
:::.~,
o
O -~ ~
'
I
HO
:20~vrrR
a-acetylbromolactose K2C03,
7aor7b ---------
DMF acetone TBAB rt
0"
0
"-
OH .
01-1.:..
I
I
I
NH,H20 CH,O H
'U
" '
0
"-
,
rt
I
I
#
o
0
3a R=H
10a R=H
10b R=CI
3b R=CI
Scheme
1
Synthetic route of flavonoid 7-0-~-D-glycosides
1a-3a and 1b-3b
* Correspondent.E-mail:WangQA@hnu.cn

196 JOURNAL OF CHEMICAL RESEARCH 2009
Synthesis of7-hydroxyflavone 7a and 7-hydroxy-4'-chloroflavone 7b
The compound 6a (1.34 g 4 mmol) or the compound 6b (1.66 g,
4 mmol) was dissolved io glacial acetic acid (15 mL), aod concentrated
sulfuric acid (1 mL) was added. The mixture was poured carefully
into crushed ice containing 100 mL of water, vigorous stirring
was continued for 30 min, aod the mixture was then placed io the
refrigerator overnight. The resulting solid was filtered aod washed
with water (100-200 mL). The product was vacuum dried at 60°C
to provide 7a as a white solid 0.7 g (yield 82%); 7b as a white solid
1.02 g (yied 85%).
Th. Low yields and complications
product were encountered in the benzoylation
condensation steps. We improved the synthetic
in the isolation of the
and Claisen
method
and found that the reaction under phase transfer conditions
(K2C03, acetone, TBAB, reflux) resulted in the formation of
the 1,3-diketone 6a and 6b in good yields.
7-Hydroxyflavones
a-acetylbromoglucose,
acetylbromolactose
7a and 7b were condensed
a-acetylbromogalactose and
respectively by using
with
a-
anhydrous
7a: m.p. 24l-243°C (lit'3 239-240°C); 'H NMR (400 MHz,
DMSO-d6): 8 10.83 (lH, s, 7-0H), 8.09 (lH, d, J= 8.4 Hz, H-5),
8.05 (2H, m, H-2',6'), 7.99 (lH, d, J = 2.2 Hz, H-8), 7.4-7.6 (3H,
m, H-3',4',5'), 6.94 (lH, dd, J= 8.4, 2.2 Hz, H-6), 6.90 (lH, s, H-3);
MS (API-ES, Neg, Scao) m/z (%): 236.9 (100%), 237.9 (15%).
7b: m.p. 280-282°C (lit'3 280-282°C); 'H NMR (400 MHz,
DMSO-d6): 8 10.86 (lH, s, 7-0H), 8.09 (2H, d, J = 8.4 Hz, H-3',
5'),7.99 (lH, d, J= 8.4 Hz, H-5), 7.9 (lH, d, J= 8.4 Hz, H-8), 7.63
(2H, d, J= 8.4 Hz, H-2', 6'), 7.01 (lH, dd, J= 8.4, 2.2 Hz, H-6), 6.93
(lH, s, H-3); MS (API-ES, Neg, Scao) m/z (%): 301.0 (100%), 303.0
(30%).
K2C03 in a solvent mixture of DMF /acetone (3 :2 VIV) and
tetrabutylammonium bromide (TBAB) as phase transfer
a
catalyst at room temperature, to yield the protected flavonoid
glycosides 8a-10a and 8b-10b.
We tried to deacetylate
standard procedure using KOH in EtOH, However,
found that the strong basic condition resulted in cleavage
partly of the flavone ring and gave some by-products.
of 8a-10a
and 8b-10b
by a
we
C
Careful deprotection of the acyl groups under mildly alkaline
condition (NH3'H20 in MeOH) at room temperature afforded
Synthesis of7-0-13-D-acetylglucosylflavone
D- acetylglucosyl flavone 8b
8a and 4-chloro-7-0-13-
the desired flavonoid 7-0-13-D-glycosides
1a-3a and 1b-3b
in satisfactory yields. The structures of the target compounds
Anhydrous K2C03 (4 g, 12.6 mmol) was added to the mixture of
DMF (15 mL) aod acetone (9 mL), then 7a (142 mg, 0.6 mmol) or
7b (181 mg, 0.6 mmol) io a 50 mL round-bottomed flask. TBAB
(1.5 mg) aod a-acetylbromoglucose (500 mg, 1.2 mmol), were
added with stirriog, After stirriog for 12 h at room temperature, the
acetone was removed under vacuum aod water (30 mL) was added
to the flask. The orgaoic layer was washed with water (30 mL) aod
brine (30 mL), dried over anhydrous MgS04. Then the solvent was
removed to give the solid which was recrystallised from EtOH to
give white needle of 8a or 8b.
8a: 306 mg; yield 91%; m.p. l78-179°C (lit'4 l8l-l82°C);
'H NMR(400 MHz, CDC13): 88.10 (lH, d, J= 8.3 Hz, H-5), 8.04
(2H, m, H-2', 6'), 7.92 (lH, d, J= 2.3 Hz, H-8), 7.60 (3H, m, H-3', 4',
5'),7.41 (lH, s, H-3), 7.03 (lH, dd, J= 8.8, 2.3 Hz, H-6), 5.84 (lH,
d, J= 7.6 Hz, H-l"), 5.43 (1H, m, H-3"), 5.15-5.05 (2H, m, H-2", H-
6a"), 4.37-4.20 (2H, m, H-5", H-6b"), 4.12 (lH, m, H-4"), 2.04 (3H,
s, CH3CO), 2.03 (3H, s, CH3CO), 2.02 (3H, s, CH3CO), 1.99 (3H, s,
CH3CO); IR vrn",(KBr)/cm": 1759(C=0), l653(ArC=0), l63l(Ar),
were established by IH NMR, MS and IR spectra. In the IH
NMR spectra of compounds 1a-3a and 1b-3b, the chemical
shift of the C1-H in the glycosyl ring appeared downfield with
a coupling constant J1,2 = 7.0-10 Hz. In the IR spectra of these
compounds, the absorption of the bending vibration ofC1-H
bond in glycosyl ring appeared at about 900 cm-1. The 1H
NMR, IR spectra confirmed their 13-anomeric configuration.?
Thus, an efficient synthesis offlavonoid 7-0-13-D-glycosides
by phase transfer catalysis have been achieved as shown
in Scheme 1. The method has advantages of mild reaction
conditions, simple operation, high stereospecificity
yields. The method is significant improvement
and good
over the
a
previously reported Baker- Venkataraman flavonoid synthesis
and glycosidation
step under Koenigs-Knorr
conditions.8-9
The flavonoid 7-0-13-D-glycosides
2a, 3a and 1b-3b are new
l608(Ar), l238(Ar-0-),
1221(-0-),
1086(-0-); MS(FAB+) m/z:
compounds. The biological activity of compounds 1a-3a and
1b-3b are currently under investigation and will be reported
elsewhere.
569 (M + 1).
8b: 336 mg; yield 93%; m.p. l42-l44°C; 'H NMR (400 MHz,
CDC13): 8 8.15 (lH, d, J = 8.5 Hz, H-5), 7.83 (2H, d, J = 8.4 Hz,
H-2', 6'), 7.49 (2H, d, J= 8.5 Hz, H-3',5'), 7.12 (lH, d, J= 2.4 Hz,
H-8), 7.05 (lH, dd, J= 8.5, 2.4 Hz, H-6), 6.75 (lH, s, H-3), 5.35 (lH,
d, J= 7.6 Hz, H-l"), 5.34 (1H, m, H-3"), 5.27-5.17 (2H, m, H-2",
H-6a"), 4.29-4.21 (2H, m, H-5", H-6b"), 4.0 (lH, m, H-4"), 2.09 (3H,
s, CH3CO), 2.08 (3H, s, CH3CO), 2.07 (3H, s, CH3CO), 2.06 (3H, s,
CH3CO); MS (FAB') m/z: 601 (M-l). Anal. Calcd for C29H2P12Cl:
C, 57.77; H, 4.51. Found: C, 57.85; H, 4.59%.
Experimental
Melting points were measured on a XRC-l apparatus aod were
uncorrected. IR spectra were recorded on
a Bruker Tensor-27
Spectrometer; 'H NMR spectra were recorded on a Broker AM-
400 instrument, using tetramethylsilaoe as ao internal staodard,
chemical shifts (8) in ppm, coupling constaots(J) io Hz. Mass
spectra were determioed with ZAB- HS spectrometer by the EI
or FAB method. Elemental aoalyses were carried out on a Perkin-
Elmer 240B microaoalyser. All solvents were dried by staodard
Synthesis of7-0-13-D-acetylgalactosylflavone
13-D-acetylgalactosyl flavone 9b
9a and 4'-chloro-7-0-
9a was prepared from 7a and a-acetylbromogalactose as described
above; 9b was also prepared from 7b and a-acetylbromolactose as
described above. The physical aod spectra data of the compounds 9a
and 9b are as follows:
9a: White solid; yield 89%; m.p. 137-139°C; 'H NMR (400 MHz,
CDC13): 8 8.17 (lH, d, J = 8.4 Hz, H-5), 7.91 (2H, m, H-2',6'),
7.53 (3H, m, H-3', 4', 5'), 7.15 (lH, d, J = 2.0 Hz, H-8), 7.07 (lH,
dd, J = 8.4, 2.0 Hz, H-6), 6.79 (lH, s, H-3), 5.60 (lH, m, H-5"),
5.18 (lH, d, J = 7.6 Hz, H-2"), 5.09 (lH, m, H-4"), 4.38 (2H, m,
H-6"), 4.16 (lH, d, J= 2.8 Hz, H-3"), 4.02 (lH, t, J= 6.8 Hz, H-3"),
2.21 (3H, s, CH3CO), 2.10 (3H, s, CH3CO), 2.08 (3H, s, CH3CO),
2.04 (3H, s,CH3CO); IR vrn",(KBr)/cm": 3062(Ar-H), 175l(C=0),
procedures.
a-Acetylbromoglucose,
a-acetylbromogalactose
and a-acetylbromolactose were prepared as described in detail
previously. 1D,l'
Synthesis of diketone 6a and 6b
2,4-Dihydroxyacetophenone (1.5 g, 10 mmol), anhydrous K2C03
(10 g, 31.5 mmol) aod tetrabutylammonium bromide (TBAB)
(20 mg) io a 250 mL round-bottomed flask. Then benzoyl chloride
(2.3 mL, 20 mmol) or 4-chlorobenzoyl chloride (2.4 mL, 20 mmol)
was added dropwise 30 min with stirring. The reaction mixture was
refluxed for 14 h (monitored by TLC) aod then was cooled to room
temperature, filtered aod washed with acetone (3 mL), 10% acetic
acid (180 mL) was added to the crude product until pH ofthe mixture
was 3. The resulting solid was filtered aod washed well with cold
water. The product was dried overnight aod recrystallised form
acetone providing light yellow crystalline material. The physical aod
spectra data of the compounds 6a and 6b are as follows.
1645(ArC=0), l446(Ar), 1230(Ar-o-),
m/z: 569(M+ 1).Anal. Calcd for C29H28012:C, 61.27; H, 4.96. Found:
C,61.35; H, 5.05%.
1053(-0-); MS (FAB+)
9b: White solid; yield 89%; m.p. 90-92 DC; 'H NMR(400 MHz,
CDC13): 8 8.16 (lH, d, J = 8.8 Hz, H-5), 8.09 (2H, d, J = 8.4 Hz,
H-3', 5'), 7.62 (2H, d, J= 8.4 Hz, H-2', 6'), 7.83 (lH, d, J= 1.6 Hz,
H-8), 7.06 (lH, dd, J = 8.7,1.6 Hz, H-6), 6.75 (lH, s, H-3), 5.55 (lH,
m, H-5"), 5.50 (lH, J= 7.4 Hz, H-l"), 5.19 (lH, m, H-4"), 4.24 (2H,
m, H-6"), 4.18 (lH, J= 2.8 Hz, H-3"), 4.01 (lH, t, J= 6.8 Hz, H-2"),
2.21 (3H, s, CH3CO), 2.10 (3H, s, CH3CO), 2.09 (3H, s, CH3CO),
2.05 (3H, s, CH3CO), 2.03 (3H, s, CH3CO); MS (FAB') m/z: 601
6a: 5.0 g, yield 86%; m.p. l64-l66°C
(lit'2 l65-l66°C);
MS(FAB+) m/z: 36l(M + 1)
6b: 5.4 g, yield 87%; m.p. 205-206°C (lit'2 205-206°C);
MS(FAB+) m/z: 429 (M + 1).

JOURNAL OF CHEMICAL RESEARCH 2009 197
m, H-4"); MS (FAB') m/z: 399(M-1). Anal. Calcd for C2,H2008: C,
62.99; H, 5.03. Found: C, 63.05; H, 5.10%.
(M-1). Anal. Calcd for C29H27012C1:C, 57.77; H, 4.51. Found: C,
57.69; H, 4.60%.
2b: White solid; yield 87%; m.p. 106-108°C; 'HNMR (400 MHz,
CDC13): 1) 8.11 (2H, d, J= 8.8 Hz, H-2', 6'), 7.97 (lH, d, J= 9.0 Hz,
H-5), 7.66 (2H, d, J= 8.8 Hz, H-3', 5'), 7.39 (lH, d, J= 2.0 Hz, H-8),
7.15 (lH, dd, J= 8.9, 2.0 Hz, H-6), 7.02 (lH, s, H-3), 5.29 (lH, d,
J = 8.4 Hz, 2"-OH), 5.10 (lH, d, J = 8.0 Hz, 3"-OH), 4.93 (lH, d,
J= 5.2 Hz, 4"-OH), 4.69-4.72 (lH, t, 6"-OH), 4.57 (lH, d,J= 7.6Hz,
H-1"), 3.70-3.74 (2H, m, H-5", 6"), 3.44-3.68 (4H, m, H-2", 4", 6");
MS(FAB+) m/z: 435(M + 1). Anal. Calcd for C2,H1908C1: C, 58.01;
H, 4.40. Found: C, 58.10; H, 4.45%.
Synthesis of7-0-~-D-acetyllactosideflavone lOa and 4'-chloro-7-0-
~-D- acetyllactosideflavone lOb
lOa and lOb were prepared from 7a and a-acety1bromo1actose as
described above. The physical and spectra data of the compounds
lOa and lOb are as follows:
lOa: White solid; yield 84%; m.p. 107-109°C; 'H NMR
(400 MHz, CDC13): 1) 8.17 (lH, d, J = 8.4 Hz, H-5), 7.91 (2H, m,
H-2', 6'), 7.55 (3H, m, H-3', 4', 5'), 7.18 (lH, d, J= 2.4 Hz, H-8), 7.13
(lH, dd, J = 8.4, 2.4 Hz, H-6), 6.79 (lH, s, H-3), 5.37-3.81 (14H, m,
sugar-H), 2.17 (3H, s, CH3CO), 2.10 (3H, s, CH3CO), 2.09 (3H, s,
CH3CO), 2.08 (6H, s, CH3CO), 2.07 (3H, s, CH3CO), 1.98 (3H, s,
CH3CO). IR vrn",(KBr)/cm": 1753(C=0), 1645(ArC=0), 1446(Ar),
1230(Ar-0-), 1180(-0-). MS (FAB+) m/z: 857 (M + 1). Anal. Calcd
for C4,H44020: C, 57.48; H,5.18. Found: C, 57.41; H, 5.29%.
lOb: White solid; yield 82%; m.p. 136-137°C; 'H NMR
(400 MHz, CDC13): 1) 8.15 (lH, d, J = 8.8 Hz, H-5), 8.08 (2H, d,
J= 8.3 Hz, H-3', 5'), 7.62 (2H, d, J= 8.3 Hz, H-2', 6'), 7.84 (2H, d,
J = 1.6 Hz, H-8), 7.04 (lH, dd, J = 8.8, 2.0 Hz, H-6), 6.76 (lH, s,
H-3), 5.37-3.63 (l4H, m, sugar-H), 2.17 (3H, s, CH3CO), 2.11 (3H,
s, CH3CO), 2.09 (6H, s, CH3CO), 2.05 (6H, s, CH3CO), 1.98 (3H, s,
CH3CO), MS (FAB+) m/z: 891 (M + 1).Anal. Calcd forC4,H4302oC1:
C, 55.25; H, 4.86. Found: C, 55.31; H, 4.93%.
Synthesis of 7-0-~-D-lactoside flavone 3a and 4'-chloro-7-0-~-D-
lactosideflavone 3b
3a and 3b were prepared from lOa as described above. The physical
and spectra data of the compounds 3a and 3b are as follows:
3a: White solid; yield 84.5%; m.p. 247-249 °C; 'HNMR (400 MHz,
DMSO-d6): 1) 8.10 (2H, d, m, H-2', 6'), 7.98 (lH, d, J= 8.8 Hz, H-5),
7.58-7.62 (3H, m, H-3', 4', 5'), 7.42 (lH, d, J = 1.6 Hz, H-8), 7.16
(lH, dd, J= 8.4, 2.0 Hz, H-6), 6.99 (lH, s, H-3), 5.59-4.25 (7H, m,
sugar-OH), 4.51 (lH, d, J= 7.4 Hz, H-1"), 4.25 (lH, d, J= 7.2 Hz,
H-1"'), 3.69-3.32 (12H, m, sugar-H). IR vrn",(KBr)/cm": 3402(OH),
1635(ArC=0), 1595(Ar), 1452(Ar), 1246(Ar-o-), 1167(-0-); MS
(FAB+) m/z: 563 (M + 1). Anal. Calcd for C27H30013: C, 57.65;
H,5.37. Found: C, 57.53; H, 5.43%.
3b: Light yellow solid; yield 78%; m.p. 267-268°C; 'H NMR
(400 MHz, DMSO-d6): 1) 8.12 (2H, d, J = 8.4 Hz, H-2',6'), 7.99
(lH, d, J = 8.8 Hz, H-5), 7.66 (2H, d, J = 8.4 Hz, H-3',5'), 7.42
(lH, d, J= 1.6 Hz, H-8), 7.16 (lH, dd, J= 8.4, 1.6 Hz, H-6), 7.03
(lH, s, H-3), 5.60-4.66 (7H, m, sugar-OH), 4.46 (lH, d, J= 7.2 Hz,
H-4"), 4.29 (lH, d, J= 7.3 Hz, H-1"'), 3.30-3.78 (12H, m, sugar-H).
IR vrn",(KBr)/cm": 3477(OH), 1647(ArC=0), 1630(Ar), 1442(Ar),
1232(Ar-o-), 1072(-0-); MS (FAB+) m/z: 597(M + 1). Anal. Calcd
for C27H29013C1:C, 54.32; H, 4.89. Found: C, 54.24; H, 4.98%.
Synthesis of 7-0-~-D-glucoside flavone la and 4'-chloro-7-0-~-
D- glucosideflavone lb
Sa (0.2 g, 0.35 mmo1) or Sb (0.2 g, 0.35 mmo1) was added to a
solution of 30% NH3'HP (1.6 mI.) in MeOH (5 mI.) with stirring.
After stirring for 12 h, filtration, and drying under vacuum, yellow
powder was obtained.
la: 0.12 g; yield 86%; m.p. 250-252°C (lit'4 252-254°C);
'H NMR (400 MHz, DMSO-d6): 1) 8.10 (2H, d, J = 8.0 Hz, m,
H-2',6'), 7.98 (lH, d, J= 8.3 Hz, H-5), 7.60 (3H, m, H-3', 4',5'),7.81
(lH, d, J = 2.1 Hz, H-8), 7.16 (lH, dd, J = 8.4, 2.2 Hz, H-6), 6.99
(lH, s, H-3), 5.44 (lH, d, J= 4.0 Hz, 2"-OH), 5.16 (lH, d, J= 4.0 Hz,
3" -OH), 5.14 (lH, d, J= 5.2 Hz, 4" -OH), 5.09 (lH, d, J= 7.2 Hz, H-
1"),4.62 (lH, t, 6"-OH), 3.50-3.75 (3H, m, H-5", 6"), 3.24-3.36 (2H,
m, H-2", 3"), 3.20-3.22 (lH, m, H-4'); IR vrn",(KBr)/cm": 3442(OH),
Received 3 December 2008; accepted 23 January 2009
Paper 08/0314 doi: 10.3184/030823409X431346
Published online: 6 April 2009
3087(ArH), 1622(C=0), 1587(Ar), 1452(Ar), 1250(Ar-0-),
(-0-); MS (FAB') m/z: 399(M-1).
1176
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1991,113,2092.
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3423.
lb: 0.14 g; yield 84%; m.p. 233-234°C; 'H NMR (400 MHz,
DMSO-d6): 1) 8.13 (lH, d, J= 8.5 Hz, H-5), 7.81 (2H, d, J= 8.5 Hz,
H-2', 6'), 7.47 (2H, d, J= 8.5 Hz, H-3',5'), 7.12 (lH, d, J= 2.2 Hz,
H-8), 7.03 (lH, dd, J= 8.5, 2.2 Hz, H-6), 6.70 (lH, s, H-3), 5.44 (lH,
d, J= 4.0 Hz, 2"-OH), 5.17 (lH, d, J= 4.0 Hz, 3"-OH), 5.14 (lH, d,
J= 7.2 Hz, H-1"), 5.12 (lH, d, J= 5.2 Hz, 4"-OH), 4.60 (lH, t, 6"-
OH), 3.71-3.75 (lH, m, H-5"), 3.48-3.52 (2H, m, H-6"), 3.20-3.28
(2H, m, H-2",3"), 3.17 (lH, m, H-4"), MS (FAB+) m/z: 435(M + 1).
Anal. Calcd for C2,H1908C1: C, 58.01; H, 4.40. Found: C, 57.92; H,
4.48%.
2
3
4
5
6
7
8
9
Synthesis of7-0-~-D-galactosideflavone 2a and 4'-chloro-7-0-~-D-
galactoside flavone 2b
10 B.S.Furniss,A.J. HannafordandP.W.G.Smith,Tatehell,A.R. Textbook of
practical organic chemistry, 5th coo, with John Wilcy&Sons, New York,
1989,647.
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Pharmaceut. Sin., 1998,33,22.
12 B.S. Yan,T.M.Suo aodZ.Q. WU,Zhongguo Yaowu Huaxue Zazhi, 1994,
4,36.
13 A. Bellini aodP.Venturella,Ann. Chim. (Roma), 1958,48,111.
14 W.Baker,W.D.OllisaodV.D.Poole,J. Chem. Soc., 1952,1505.
2a and 2b were prepared from 9a as described above. The physical
and spectra data of the compounds 2a and 2b are as follows:
2a: White solid; yield 88%; m.p. 265-266°C; 'H NMR (400 MHz,
DMSO-d6): 1) 8.10 (2H, m, H-2', 6'), 7.97 (lH, d, J = 8.8 Hz, H-5),
7.60 (3H, m, H-3', 4', 5'), 7.39 (lH, d, J= 1.6 Hz, H-8), 5.25 (lH, d,
J=4.8 Hz, 2"-OH), 5.02 (lH, d,J= 8.0 Hz, H-1 "), 4.92 (lH,J= 6.0 Hz,
4"-OH), 4.69-4.72 (lH, t, 6"-OH), 4.57 (lH, m, 3"-OH), 3.71-3.74
(2H, m, H-5", 6a"), 3.53-3.68 (3H, m, H-2", 3", 6b"), 3.44-3.50 (lH,