Synthesis of vicenin-1 and 3, 6,8- and 8,6-di-C-β-d-(glucopyranosyl- xylopyranosyl)-4′,5,7-trihydroxyflavones using two direct C-glycosylations of naringenin and phloroacetophenone with unprotected d-glucose and d-xylose in aqueous solution as the key reactions

Article abstract of DOI:10.1016/j.carres.2010.04.001

Vicenin-3 was synthesized from naringenin via a short five-step reaction, which included two regioselective direct C-glycosylations with d-glucose and d-xylose (yields: 22% and 30%, respectively) as the key reactions for a total yield of 4.4%. Vicenin-1 was also synthesized from phloroacetophenone via a 10-step reaction, including the same glycosylation described above, for a total yield of 2.7% with a vicenin-3 yield of 1.7%.

Full text of DOI:10.1016/j.carres.2010.04.001

Carbohydrate Research 345 (2010) 1825–1830
Contents lists available at ScienceDirect
Carbohydrate Research
journal homepage: www.elsevier.com/locate/carres
Synthesis of vicenin-1 and 3, 6,8- and 8,6-di-C-b-D-(glucopyranosyl-xylopyrano-
syl)-40,5,7-trihydroxyflavones using two direct C-glycosylations of naringenin
and phloroacetophenone with unprotected D-glucose and D-xylose in aqueous
solution as the key reactions
*
Shingo Sato , Tomoyuki Koide
Graduate School of Science and Engineering, Yamagata University, Jonan 4-3-16, Yonezawa-shi, Yamagata 992-8510, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Vicenin-3 was synthesized from naringenin via a short five-step reaction, which included two regioselec-
Received 28 December 2009
Received in revised form 30 March 2010
Accepted 1 April 2010
tive direct C-glycosylations with D-glucose and D-xylose (yields: 22% and 30%, respectively) as the key
reactions for a total yield of 4.4%. Vicenin-1 was also synthesized from phloroacetophenone via a 10-step
reaction, including the same glycosylation described above, for a total yield of 2.7% with a vicenin-3 yield
of 1.7%.
Available online 13 April 2010
Ó 2010 Elsevier Ltd. All rights reserved.
Keywords:
Direct C-glycosylation
Sc(OTf)3
Naringenin
Phloroacetophenone
1. Introduction
thin (6-Glc-8-Rha, 6-Rha-8-Glc), and schaftoside and isoschafto-
side (6-Glc-8-Ara, 6-Ara-8-Glc).1 We have not yet attempted the
Many flavonoids in plants include glycosides that are mostly
present as water-soluble O-glycosides and, rarely, as C-glycosides.
The C-glycosylflavonoids include a few bis-C-glycosides, mostly
flavones. To date, 55 di-C-glycosylflavones have been isolated
and their structures determined.1 Many of them include apigenin
(40,5,7-trihydroxyflavone) as the aglycon. Some of these C-glyco-
sylflavonoids show bioactivities different from the corresponding
O-glycosylflavonoids and their aglycons, because of differences in
their stability to hydrolysis.2 Although there are a few reports on
the efficient synthesis of mono-C-glycosylflavonoids,3 there are
no reports on the synthesis of bis-C-glucosylflavonoids except for
a recent report.4
synthesis of bis-C-glycosides that consist of different sugars.
We previously studied an environmentally friendly method
for the direct C-glycosylation of acetylpolyphenol with a non-
protected sugar in an aqueous solution in the presence of scandium
trifluoromethanesulfonate [Sc(OTf)3].5 The first synthesis of the
three di-C-glycosylflavonoids listed above was achieved by appli-
cation of our method.4 This article describes the total synthesis
of 1 and 2 and the application of this direct C-glycosylation method
to naringenin and phloroacetophenone.
Vicenin-1 and -3 (1, 2) were isolated from the leaves of Desmo-
dium styracifolium MERR (Leguminosae), which has been used as a
Chinese folk medicine for cholelithiasis, lithiasis, and inflammation
of the liver, among other ailments.6 Vicenin-1 (1) has also been iso-
lated from Vitex lucens (Verb.),7 Arrhenatherum sp. (Gram.),8 Cymo-
phyllum fraseri (Cyp.),9 Eminium spiculatum (Acer.),10 Ephedra sp.
We have achieved the synthesis of the naturally occurring di-C-
b-
D
-glucosylflavone (vicenin-2, see Fig. 1), di-C-b-
D-glucos-
yldihydrochalcone, and di-C-b-
D
-glucosylflavanone.4 In plants,
however, it is rare to find a di-C-glycosylflavone consisting of
two alternative sugars as a bis-C-glycoside, which consists of five
kinds of
D
-sugars, such as glucose, galactose, xylose, arabinose,
OH
R2
and rhamnose.1 Three kinds of 6,8-di-C-glycosyl-40,5,7-trihydr-
oxyflavones have been isolated from plants: vicenin-1 and -3 [6-
Xyl-8-Glc (1), 6-Glc-8-Xyl (2), see Fig. 1], violanthin and isoviolan-
HO
R1
O
O
Vicenin-1: R1 = Xyl, R2 = Glc
Vicenin-2: R1, R2 = Glc
OH
Vicenin-3: R1 = Glc, R2 = Xyl
* Corresponding author. Tel./fax: +81 238 26 3121.
E-mail address: shingo-s@yz.yamagata-u.ac.jp (S. Sato).
Figure 1. Structure of vicenin-1 (1), -2, and -3 (2).
0008-6215/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.carres.2010.04.001

1826
S. Sato, T. Koide / Carbohydrate Research 345 (2010) 1825–1830
(Ephed.),11 and Rhynchosia jacobii (Leg.),12 and 2 has been isolated
from V. lucens (Verb.),7 Camellia sinensis (Thea.),13 Ephedra sp.
(Ephed.),11 and Premna integrifolia (Verb.).14 However, the bioactiv-
ity of these compounds has not yet been reported.
The synthesis of 1 and 2 was examined by two methods: (1) a
readily available method of two regioselective direct C-glycosyla-
tions of naringenin, followed by oxidation, and (2) two direct
C-glycosylations of phloroacetophenone, followed by aldol con-
densation, acid-cyclization, and then oxidation (Scheme 1).
included unreacted D-glucose and Sc(OTf)3. The eluate, with 50%
aqueous acetone and acetone–MeOH, including naringenin and
naringenin glycosides, was evaporated to give an amorphous solid,
which was subjected to silica-gel column chromatography
(15:30:2:0.1 and 30:30:5:0.1 acetone–EtOAc–H2O–AcOH). As a re-
sult of this experiment, the naringenin mono-C-glucoside 3 was
afforded as a pale-yellow amorphous powder in 22% yield. Since
it was unclear whether
3 was 6-C-b-D- or 8-C-b-D-glu-
copyranosylnaringenin, 3 was acetylated by Ac2O, pyridine, and
N,N-dimethylaminopyridine (DMAP). Using 1H NMR spectroscopy,
4
the chemical shift of an aromatic proton of the acetate 30 was
2. Results and discussion
compared with that of the acetates of 6-C-b-
D-glucosylnaringenin
(hemiphloin) and 8-C-b-
D-glucosylnaringenin (isohemiphloin).
Direct C-glycosylation of naringenin, in which the phenolic hy-
droxyl groups are partially benzyl protected, has been attempted
by our group3c and by Oyama and Kondo,3g whose attempts were
unsuccessful. Kondo’s group achieved the C-glycosylation of
naringenin after reduction of its carbonyl group to a methylene
residue. We also tried the direct C-glycosylation of unprotected
Since the chemical shift (d in CDCl3) of the acetate 30 was 6.79,4
and that of hemiphloin and isohemiphloin hepta-acetates was
6.79 and 6.56, respectively,15 mono-C-glycoside 3 was determined
to be a 6-C-b-D
-glucopyranosyl-40,5,7-trihydroxyflavanone. This re-
sult suggests that the C-glycosylation of naringenin with
proceeded both regioselectively and stereoselectively.
Next, a second C-glycosylation of 3 with
ined. The best conditions were as follows. An aqueous EtOH solu-
tion (2:1 EtOH–water) of and 2.5 equiv of -xylose was
refluxed at 80 °C for one day in the presence of 0.5 equiv of
Sc(OTf)3. The reaction mixture was worked up and purified in the
same manner as described above. The desired 6-C-b-
D-glucose
naringenin with D-glucose in an aqueous solution in the presence
D-xylose was exam-
of catalytic amounts of Sc(OTf)3 and found that this method affor-
ded 6- or 8-C-glucosyl-40,5,7-trihydroxyflavanone and 6,8-di-C-
glucosyl-40,5,7-trihydroxyflavanone in 17.3% and 19.0% yields,
respectively.4 Herein, we applied this method to direct C-glycosyl-
ation of naringenin with D-glucose and D-xylose in the synthesis of
1 and 2.
Direct C-glycosylation of naringenin and isolation of the desired
glycoside were performed as follows. An aqueous CH3CN solution
(2:1 CH3CN–H2O) of naringenin (1 equiv) and D-glucose (2.5 equiv)
was refluxed in an oil bath (85 °C) for 12 h in the presence of
0.2 equiv of Sc(OTf)3. The reaction mixture was diluted with water
(50 mL) and was then placed and absorbed onto a column of Diaion
CHP20P resin (ca. 50 mL in water). The resulting resin was washed
with water (200 mL) and then eluted with 50% aqueous acetone
(100 mL) and 1:1 acetone–MeOH (100 mL). Unabsorbed fractions
3
D
D-glucopyran-
osyl-8-C-b- -xylopyranosylnaringenin (4) was obtained in a yield
D
of 30%. Acetylation (Ac2O–pyridine–DMAP) of 4 gave deca-acetate
5 in a yield of 80%, and the structure of 4 was confirmed by a de-
tailed analysis of the 1H and 1H–1H correlation NMR spectroscopy
of 5.
Next, synthesis of flavones via oxidation of flavanone acetate 5
was examined. Dichlorodicyanobenzoquinone (DDQ) was previ-
ously used in the oxidation reaction.3g,4 After oxidation followed
by acetylation (Ac2O–pyridine), separation and purification were
OH
OH
OH
OH
Sc(OTf)3 (0.2 equiv)
D-glucose (2.5 equiv)
HO
O
O
HO
O
O
Sc(OTf)3 (0.5 equiv)
D-xylose (2.5 equiv)
O
OH
HO
HO
HO
O
CH3CN / H2O (2:1)
reflux for 12h
HO
O
O
EtOH / H2O (2:1)
at 80 ºC for 1day
OH
OH
HO
HO
HO
OH
O
Y:22%
3
OH
Y:30%
HO
OH
4
OAc
OAc
OAc
OAc
O
OAc
AcO
AcO
O
OAc
AcO
AcO
1) I2 (1 equiv) / Py
reflux for 8h
O
O
Ac2O / Py
Y:80%
AcO
AcO
O
AcO
AcO
1) NaOMe in MeOH
O
2) Ac2O / Py
Y:91%
OAc
2) Dowex 50W x 8 (H+)
Y92%
AcO
OAc
OAc O
5
AcO
OAc O
6
OH
OH
O
OH
HO
HO
O
O
O
HO
HO
HO
OH
OH
overall yield:4.4%
vicenin-3 (2)
Scheme 1. Synthesis of vicenin-3 (2) via direct C-glucosylation and C-xylosylation of naringenin.

S. Sato, T. Koide / Carbohydrate Research 345 (2010) 1825–1830
1827
carried out. However, since the separation of products from the
resulting hydroquinone acetates was difficult, and the yield was
a low 30%, oxidation using iodine was employed.16 Halogenation
er. Total yield of the synthesis of 1 from phloroacetophenone was
2.75%, together with a yield of 1.68% of 2. The 13C NMR spectral
data for the compounds were in agreement with the data obtained
for the natural products6 (see Table 1).
of
a-H in 5, followed by elimination of HI due to pyridine, pro-
ceeded smoothly. A solution of 5 in pyridine was refluxed for 8 h
in the presence of 1 equiv of iodine, followed by re-acetylation
(Ac2O–pyridine) to afford flavone deca-acetate 6 as a yellow amor-
phous solid in a yield of 91%, which was O-de acetylated by sodium
methoxide in dry MeOH and neutralized by Dowex 50Wx8 (H+) re-
sin to afford the desired 2 in a yield of 92%. Total synthesis of 2 was
achieved via a five-step-reaction, including two direct C-glycosyla-
tions from naringenin, in a total yield of 4.4%.
We also examined the Wessely–Moser isomerization of 2. Com-
pound 2, which was synthesized from naringenin, was refluxed in
6 N HCl for 2 h. After removal of the solvents, HPLC analysis (mon-
itoring: UV 254 nm) of the residual solid showed that 1 and 2 were
included at 31% and 40%, respectively. These results showed that
acid isomerization of 2 synthesized from naringenin via the five-
step reaction gave 1 in a yield of 31%.
The synthesis of 1 was examined in the same manner as that of
3. Conclusions
2 (see Scheme 2). Direct C-glycosylation of naringenin with
lose gave the desired C-b- -xylosylnaringenin 7 in a 13% yield,
along with a 5% yield of 6,8-di-C-b- -xylosylnaringenin 8. Since
D-xy-
D
We accomplished the first total synthesis of 6-C-b-
C-b-
-xylosyl-40,5,7-trihydroxyflavone, vicenin-3 (2) by a short,
five-step reaction involving direct C-glycosylation with -glucose
and -xylose performed twice, followed by oxidation of the acetate
D-glucosyl-8-
D
D
the chemical shift of an aromatic proton appeared at 6.75 ppm in
D
the 1H NMR spectrum of the acetate of 7, the structure of 7 was
D
determined to be 6-C-b-
a second C-glycosylation of 7 with
the same conditions as those for 2. However, none of the desired 6-
C-b- -xylosyl-8-C-b- -glucosylnaringenin 10 was produced. Since
D
-xylopyranosylnaringenin, as was 3. Next,
using iodine and pyridine, for a total yield of 4.4%. The first total
synthesis of a regioisomer of 2, vicenin-1 (1), was achieved by
D-glucose was examined under
two direct glycosylations of phloroacetophenone with
D-glucose
D
D
and -xylose, followed by benzyl protection of the phenolic OH
D
this reaction yielded some derivatives of 7, it was found that 7
group and aldol condensation, acid-catalyzed cyclization, oxidation
of flavanone acetate, deprotection, and HPLC separation, via a total
10-step reaction, in a total yield of 2.75%, along with a vicenin-3
yield of 1.68%.
was unstable and was converted to spiro-compounds17 under
these harsher reaction conditions. The synthesis of
1 using
naringenin as a starting material was, therefore, abandoned.
The synthesis of 1 was changed so that two direct C-glycosyla-
tions of phloroacetophenone were the key reactions (Scheme 3).
4. Experimental
4.1. General
This method can employ a first C-glycosylation with
and a subsequent C-glycosylation with -xylose, as well as the syn-
thetic method of 2. The first C-glycosylation of phloroacetophe-
none, using -glucose in the manner described above, gave
mono-glycoside 11 in a yield of 48%.5 The successive second C-gly-
cosylation of 117 with
-xylose gave the desired bis-C-glycoside 12
D-glucose
D
D
Sc(OTf)3. (Taiheiyo Kinzoku Co. Ltd) was purchased and used
without any further purification. Reactions were monitored using
TLC on 0.25-mm Silica Gel F254 plates (E. Merck), UV light, and a
7% ethanolic solution of phosphomolybdic acid, followed by heat,
were used as detection methods. Column chromatography was
performed on MCI gel CHP20PÒ (high porous polymer, 75–
D
in a yield of 29%. Three phenolic hydroxyl groups in 12 were pro-
tected with a benzyl group to give 13 in a yield of 61%. Aldol
condensation of 13 with p-benzyloxybenzaldehyde in the presence
of sodium methoxide in dried MeOH gave chalcone 14 in a yield of
90%. A methanolic solution of 14 was refluxed in the presence of
Dowex 50Wx8 (H+) resin to give flavanone, which was successively
O-de-benzylated by hydrogenolysis (H2/10% Pd–C) and acetylated
by Ac2O–pyridine–DMAP to afford flavanone acetates (a mixture
of 5 and its regioisomer). The mixture of flavanone acetates was
oxidized by iodine and pyridine followed by acetylation (Ac2O–
pyridine–DMAP) to give the desired di-C-glycosylflavone deca-ace-
tates (a mixture of 6 and its regioisomer 15) in a yield of 70%. The
mixture of acetates 6 and 15 was separable by preparative HPLC:
however, the separation of a mixture of 1 and 2 was much easier.
The mixture of acetates was deprotected by NaOMe followed by
Dowex 50Wx8 (H+) resin treatment to afford a mixture of 1 and
2. The resulting mixture was separated by preparative HPLC (ODS
column, 40:60 MeOH–5% AcOH aqueous solution) to give 1 and 2
in a ratio of 62:38. Fortunately, the ratio of the desired 1 was high-
150
l
m, Mitsubishi Chemical Corp.), and flash column chromatog-
m, Kanto Reagents Co.
raphy was performed on silica-gel (40–50
l
Ltd, silica gel 60) to separate and purify reaction products. HPLC
analysis and separation were performed using an Inertsil ODS-3
column (GL Science;
5
l
m, 4.6 ꢀ 250 mm for analytical use,
20 ꢀ 250 mm for preparative use; mobile phase: CH3CN or
MeOH–5% AcOH aqueous solution). Optical rotations were re-
corded on a JASCO DIP-370 polarimeter. IR spectra were recorded
on a Horiba FT-720 spectrometer using KBr disks. NMR spectra
were recorded on a Varian Inova 500 spectrometer using Me4Si
as the internal standard. Mass spectral data were obtained by
fast-atom bombardment (FAB) using m-nitrobenzylalcohol (NBA)
or glycerol as the matrix on a JEOL JMS-AX505HA instrument. Ele-
mental analyses were performed on a Perkin–Elmer PE 2400 II
instrument. After drying at 80–100 °C under reduced pressure for
over 2 h, each product was subjected to elemental analysis.
OH
OH
OH
OH
OH
Sc(OTf)3 (0.5 equiv)
Sc(OTf)3 (0.2 equiv)
D-xylose (2.5 equiv)
HO
O
O
HO
O
O
O
HO
OH
D-glucose (2.5 equiv)
O
2:1 CH3CN−H2O
reflux for 8 h
(13%)
HO
O
HO
HO
2:1 EtOH−H2O
at reflux for 1 day
OH
OH
OH
O
HO
HO
7
+ 8 (5%)
OH
OH
O
10
Scheme 2. Attempt to synthesize vicenin-3 (2) via direct C-xylosylation and C-glucosylation of naringenein.

1828
S. Sato, T. Koide / Carbohydrate Research 345 (2010) 1825–1830
OH
OH
O
HO
HO
OH
Ac
HO
OH
Ac
Sc(OTf)3 (0.2 equiv)
D-glucose (2.5 equiv)
Sc(OTf)3 (0.5 equiv)
D-xylose (2.5 equiv)
HO
HO
BnBr (4.5 equiv)
O
HO
OH
Ac
K2CO3 (4.5 equiv)
2:1 CH3CN−H2O
reflux for 8 h
HO
HO
OH
11
2:1 EtOH−H2O
at reflux for 1 day
(29%)
HO
O
OH
OH
(61%)
OH
(48%)
HO
OH
12
OH
OH
OH
OH
1) Dowex 50W x 8 (H+)
in MeOH reflux
O
O
HO
HO
2) H2/10% Pd−C
BnO
CHO
BnO
OBn
OBn
BnO
O
OBn
Ac
HO
HO
HO
HO
O
(92%)
NaOMe−MeOH
rt, 1 day
OH
OH
HO
HO
OBn O
OBn
(90%)
14
13
OH
OH
OH
1) Ac2O/Py
2) I2 (1 equiv) / Py
reflux for 8 h
O
1) NaOMe in MeOH
HO
OH
6 and
its regioisomer 15
3) Ac2O / Py
5
and
its regioisomer
2) Dowex 50W x 8 (H+)
3) HPLC separation
HO
O
O
(70%)
O
(90%) (1:2 = 62:38)
HO
HO
OH
+ Vicenin-3 (2)
Vicenin-1 (1)
OH
Scheme 3. Synthesis of vicenin-1 (1) and -3 (2) via two direct C-glycosylations of phloroacetophenone.
Table 1
0.36 mmol). The reaction mixture was diluted with H2O (50 mL)
and passed through
column of MCI GEL CHP20PÒ
13C NMR spectral data for vicenin-1 and -3 (1 and 2)
a
(2.5 ꢀ 100 mm) loaded with water, and the gel was washed with
200 mL of water and eluted with 100 mL of 50% aq acetone and
100 mL of 1:1 acetone–MeOH. The combined eluate was evapo-
rated to give a pale-yellow crude product, which was purified by
silica-gel column chromatography (15:30:2:0.1 acetone–AcOEt–
H2O–AcOH) to give 3 (175 mg, 22%) as a pale-yellow amorphous
powder. Product 3 was an inseparable 1:1 diastereomeric mixture,
with rotamers observed by 1H NMR spectroscopy.
Compound
Carbon
1
2
Naturala
Synthetic
Naturala
Synthetic
2
3
4
5
6
7
8
9
164.0
102.8
182.3
161.2
108.7
159.7
103.8
154.5
102.8
121.8
128.7
116.0
161.3
116.0
128.7
72.0
71.0
79.2
70.2
81.5
60.9
74.6
70.4
78.6
163.9
102.8
182.1
161.1
108.7
159.5
103.7
154.7
102.8
121.5
128.5
115.9
160.0
115.9
128.5
72.1
71.3
79.5
69.7
81.8
60.5
74.1
70.2
78.8
164.0
102.9
182.2
161.2
108.0
159.2
104.7
154.9
103.9
121.8
128.5
116.0
161.3
116.1
128.5
74.2
70.6
79.2
70.2
81.3
60.6
75.0
71.9
78.4
163.8
102.6
182.1
161.0
107.8
158.9
104.5
154.7
103.6
121.5
128.3
115.8
161.1
115.8
128.3
73.9
70.4
78.9
70.0
81.0
60.4
74.7
71.6
78.1
IR (KBr)
m .
3400, 2898, 1716, 1643, 1616, 1519, 1458 cmꢁ1 1H
NMR (DMSO-d6) d 2.70 (1H, dd, J 17.2, 3.1 Hz, H3a), 3.06 (1H, t, J
9.2 Hz, H30), 3.09 (1H, ddd, J 1.6, 6.1, 8.5 Hz, H50), 3.15 (1H, t, J
8.5 Hz, H40), 3.23 (1H, dd, J 12.6, 17.1 Hz, H3b), 3.36 (1H, dd, J
6.1, 11.7 Hz, H60a), 3.64 (1H, d, J 11.5 Hz, H60b), 3.95 (1H, br. t,
H20), 4.46 (1H, J 9.8 Hz, H10), 4.45 (1H, br s, OH), 4.58 (1H, br t,
60-OH), 4.83 (2H, br s, OH ꢀ 2), 5.40 (1H, dd, J 12.4, 2.3 Hz, H2),
5.93 (1H, s, H8), 6.78 (2H, d, J 8.4, H30,50), 7.30 (2H, d, J 8.4 Hz,
H20,60), 9.58, 10.5, 12.7 (each 3H, s, br s ꢀ 2, PhOH ꢀ 3). FABMS
10
10
20
30
40
50
60
G1
G2
G3
G4
G5
G6
X1
X2
X3
X4
X5
(negative-ion, m/z): 433 (MꢁH)ꢁ. Anal. Calcd for C21H22O10
ꢂ
0.75H2O: C, 56.31; H, 5.29. Found: C, 56.33; H, 5.52.
4.3. 6-C-b-D-Glucopyranosyl-8-C-b-D-xylopyranosylnaringenin
(4)
70.4
70.0
70.2
69.3
71.5
69.9
71.2
69.6
A solution of 3, D-xylose, and Sc(OTf)3 in 2:1 EtOH–H2O (4 mL)
was stirred at 80 °C for one day. The reaction mixture was sepa-
rated and purified in the same manner as that used for 3 to give
4 (78 mg, 30%) as a pale-yellow amorphous powder. Product 4
was an inseparable 1:1 diastereomeric mixture, with rotamers ob-
served by 1H NMR spectroscopy.
a
Measured at 90 °C.
4.2. 6-C-b-D-Glucopyranosylnaringenin (3)
IR (KBr)
m .
3363, 2917, 1626, 1518, 1458 cmꢁ1 1H NMR (DMSO-
A solution of naringenin (500 mg, 1.83 mmol) and
D-glucose
d6) d 2.80–2.86 (1H, m, H3a), 2.98–3.14 (3H, m), 3.26 (3H, m), 3.50–
3.88 (4H, m), 4.47 (1H, m), 4.60–4.83 (4H, m, OH ꢀ 4), 4.90 (1H, m),
(823 mg, 4.57 mmol) in 2:1 CH3CN–H2O (50 mL) was refluxed in
an oil bath for 12 h in the presence of Sc(OTf)3 (180 mg,

S. Sato, T. Koide / Carbohydrate Research 345 (2010) 1825–1830
1829
4.88–5.02 (3H, OH ꢀ 3), 5.36 (0.5H, dd, J 2.4, 12.9, H300), 5.47 (0.5H,
dd, J 2.8, 12.8, H300), 6.78 (2H, m, J 8.5, H30,50), 7.32 (2H, m, J 8.5,
H20,60), 9.25 (1H, br. s, 40-OH), 9.53 and 9.56 (each 0.5H, s, 7-OH),
12.76 and 12.77 (each 0.5H, s, 5-OH). FABMS (negative-ion, m/z)
565 (MꢁH)ꢁ. Anal. Calcd for C26H30O14ꢂ0.5H2O: C, 54.25; H, 5.44.
Found: C, 54.45; H, 5.66.
13, 14, and 1 was carried out at 80 °C or at 120 °C in DMSO-d6 be-
cause rotamers were not observable.
½
a 2D2
ꢃ
+23.3 (c 0.275, MeOH). IR (KBr)
.
m 3392, 2923, 1653,
1575 cmꢁ1 1H NMR (DMSO-d6 + D2O, at 80 °C) d 3.24 (1H, t, J
10.7), 3.30 (1H, t, J 8.6), 3.61 (1H, dd, J 3.8, 12.5), 3.69 (1H, dd, J
1.6, 12.2), 3.89 (1H, t, J 9.2, 9.4), 3.93 (1H, dd, J 5.3, 11.1), 4.77
(1H, d, J 9.8, H10), 4.81 (1H, J 9.8, H1), 6.71 (1H, s, H3), 9.17 (1H,
br s, 7-OH), 10.15 (1H, br s, 40-OH), 13.64 (1H, s, 5-OH). FABMS (po-
sitive-ion, m/z) 565 (M+H)+, (negative-ion, m/z) 563 (MꢁH)ꢁ. Anal.
Calcd for C26H28O14ꢂ2.5H2O: C, 51.22; H, 5.47. Found: C, 51.19; H,
5.14.
4.4. 6-C-b-D-Glucopyranosyl-8-C-b-D-xylopyranosylnaringenin
deca-acetate (5)
Flavanone 3 (100 mg, 0.17 mmol) was dissolved in pyridine
(0.5 mL) and Ac2O (0.5 mL), and DMAP (ca. 20 mg) was added to
the mixture. The mixture was stirred at room temperature for
16 h. The reaction mixture was poured into ice-cold water
(30 mL) and stirred for 0.5 h, and then extracted with AcOEt
(10 mL ꢀ 2). The combined organic layer was washed with water
and brine and dried over Na2SO4. After removal of the organic sol-
vent, the residual solid was purified by silica-gel column chroma-
tography (2:1 AcOEt–n-hexane) to give 5 (139 mg, 89%) as a
colorless amorphous powder.
4.7. 6-C-b-
D-Xylopyranosylnaringenin (7) and 6,8-di-C-b-D-
xylopyranosylnaringenin (8)
Synthesis and purification were carried out in the same manner
as that used for 3 to give 7 (13%) and 8 (5%) as pale-yellow amor-
phous powders. Products 7 and 8 were an inseparable 1;1 diaste-
reomeric mixtures, with rotamers observed by 1H NMR
spectroscopy.
IR (KBr)
m
2943, 1766, 1757, 1656, 1604 cmꢁ1. 1H NMR (CDCl3) d
aglycon moiety: 2.32, 2.44, and 2.50 (each 3H, s, ArOAc ꢀ 3), 2.79
(1H, dd, J 2.7, 16.8, H3a), 2.95 (1H, dd, J 14.4, 16.8, H3b), 5.74
(1H, dd, J 2.7, 14.4, H2), 7.23 (2H, d, H30,50), 7.58 (2H, d, J 8.6,
H20,60), xylose moiety: 3.27 (1H, t, J 10.8, H5a), 3.94 (1H, d, J 9.4,
H1), 4.25 (1H, t, dd, J 5.6, 10.8, H5b), 5.26 (2H, t, J 9.3, H3,4), 5.61
(1H, t, J 9.4, H2), glucose moiety: 3.77 (1H, dt, J 4.5, 9.5, H5), 4.25
(1H, dd, J 12.5, 4.5, H6a), 4.43 (1H, dd, J 12.5, 4.5, H6b), 4.72 (1H,
d, J 9.5, H1), 5.61 (1H, t, J 9.5, H3), 5.81 (1H, t, J 9.5, H2). 1.78,
1.91, 1.99, 2.02, 2.03, 2.04, 2.07 (each 3H, s, OAc ꢀ 7). FABMS (po-
sitive-ion, m/z) 987 (M+H)+. Anal. Calcd for C46H50O24: C, 55.98; H,
5.11. Found: C, 55.83; H, 5.12.
4.7.1. Data for 7
IR (KBr)
m
3352, 2914, 1641, 1516, 1462 cmꢁ1. 1H NMR (DMSO-
d6) d 2.68 (1H, dd, J 2.9, 17.1, H3a), 3.01 (1H, t, J 10.6, H500a), 3.09
(1H, t, J 8.4, H300), 3.24 (1H, dd, J 12.9, 17.1, H3b), 3.33 (1H, ddd, J
4.9, 5.2, 10.6, H400), 3.70 (1H, dd, J 5.2, 10.6, H500b), 4.37 (1H, d, J
9.8, H100), 4.56 (1H, br s, 2-OH), 4.84 (1H, br s, 3-OH), 4.87 (1H, d,
J 4.9, 4-OH), 5.39 (1H, dd, J 2.9, 12.7, H2), 5.92 (1H, s, H8), 6.78
(2H, d, J 8.5, H30,50), 7.30 (2H, d, J 8.5, H20,60), 9.60 (1H, s, 7-OH),
10.69 (1H, br s, 40-OH), 12.72 (1H, s, 5-OH). FABMS (positive-ion,
m/z) 405 (M+H)+. Anal. Calcd for C20H20O9ꢂ0.25H2O: C, 58.75; H,
5.05. Found: C, 58.85; H, 4.92.
4.5. 6-C-b-
trihydroxyflavone deca-acetate (6)
D-Glucopyranosyl-8-C-b-D
-xylopyranosyl-40,5,7-
4.7.2. Data for 8
IR (KBr)
m .
3396, 2910, 2871, 1628, 1516, 1458 cmꢁ1 1H NMR
(DMSO-d6) d 2.82 (1H, dt, J 3.0, 17.3, H3a), 3.02–3.16 (5H, m),
3.43 (1H, m), 3.71–3.79 (2H, m), 4.47–4.53 (2H, m), 4.66–4.84
(2H, m, OH ꢀ 2), 4.91–4.96 (4H, m), 5.35 (0.5H, dd, J 2.9, 12.7,
H300), 5.45 (0.5H, dd, J 2.8, 12.8, H300), 6.77 and 6.78 (each 1H, d, J
8.5, H30,50), 7.32 (2H, m, J 8.5, H20,60), 9.07 (1H, br s, 40-OH), 9.53
and 9.56 (each 0.5H, s, 7-OH), 12.80 and 12.81 (each 0.5H, s, H5).
FABMS (positive-ion, m/z) 537 (M+H)+. Anal. Calcd for
C25H28O13ꢂ2H2O: C, 52.44; H, 5.63. Found: C, 52.60; H, 5.83.
A solution of 5 (50 mg, 0.05 mmol) and iodine (12.6 mg,
0.05 mmol) in pyridine (2 mL) was refluxed for 8 h. The reaction
mixture was allowed to cool to room temperature, and it was then
filtered. The filtrate was evaporated in vacuo. The residual solid
was re-acetylated in the same manner as for the acetylation of 4.
The acetylated product was purified by silica-gel column chroma-
tography (2:1 AcOEt–n-hexane) to give 6 (45 mg, 91%) as a pale-
yellow amorphous powder. ½a D22
ꢁ5.19 (c 0.385, MeOH). IR (KBr)
ꢃ
m
2950, 2864, 1782, 1743, 1652, 1600 cmꢁ1. 1H NMR (CDCl3) d agly-
4.8. 6-C-b-D-Xylopyranosylnaringenin hexa-acetate (9)
con moiety: 2.35, 2.49, 2.56 (each 3H, s, ArOAc ꢀ 3), 6.60 (1H, s,
H3), 7.37 (2H, d, J 8.8, H30,50), 7.99 (2H, d, H20,60), xylose moiety:
3.41 (1H, t, J 11.1, H5a), 4.39 (1H, dd, J 11.1, 5.6, H5b), 4.50 (1H,
d, J 9.8, H1), 5.23 (1H, ddd, J 9.5, 5.6, 11.1, H4), 5.41 (1H, t, J 9.5,
H3), 5.68 (1H, t, J 9.5, H2), glucose moiety: 3.80 (1H, dd, J 9.8,
4.7, H5), 3.95 (1H, d, J 12.9, H6a), 4.45 (1H, dd, J 4.7, 12.9, H6b),
4.84 (1H, J 9.8, H1), 5.16 (1H, dt, J 9.8, H4), 5.30 (1H, t, J 9.8, H3),
5.71 (1H, t, J 9.8, H2), 1.76, 1.88, 2.01, 2.02, 2.05, 2.07, 2.10 (each
3H, s, OAc ꢀ 7). FABMS (positive-ion, m/z) 985 (M+H)+. Anal. Calcd
for C46H48O24: C, 56.10; H, 4.91. Found: C, 55.89; H, 5.13.
Naringenin mono-C-glycoside 7 (100 mg) was dissolved in pyr-
idine (2 mL), and Ac2O (2 mL) and the mixture was stirred at room
temperature for 16 h. The reaction mixture was poured into ice-
cold water and stirred for 0.5 h and then twice extracted with
AcOEt. The organic layer was washed with water and brine, and
then dried over anhyd Na2SO4. After evaporation, the residue was
purified by silica-gel column chromatography (60:1 CHCl3–EtOH)
to afford acetate 9 (151 mg, 93%) as a pale-yellow amorphous solid.
IR (KBr)
m .
2949, 2860, 1778, 1751, 1693, 1618 cmꢁ1 1H NMR
4.6. 6-C-b-
trihydroxyflavone, vicenin-3 (2)
D-Glucopyranosyl-8-C-b-D
-xylopyranosyl-40,5,7-
(CDCl3) d 1.84 and 1.86 (3H, each s, OAc), 2.04 and 2.06 (each
3H, s, OAc ꢀ 2), 2.31 and 2.38 (each 3H, s, OAc ꢀ 2), 2.43 and
2.44 (3H, each s, OAc), 2.75 (1H, dd, J 2.6 and 16.6 Hz, H-3a), 3.01
(1H, m, H-3b), 3.36 (1H, m, H-500a), 4.13(1H, d, J 9.5 Hz, H100),
4.62 (1H, m, H-500b), 5.02 (1H, t, J 9.5 Hz, H-400), 5.25 (1H, t, J
9.5 Hz, H-300), 5.47 (1H, m, H-2), 5.57 (1H, t, J 9.5 Hz, H-200), 6.77
and 6.78 (1H, s, H-8), 7.15 (2H, d, J 8.6 Hz, H-30,50), 7.44 (2H, d, J
8.6 Hz, H20,50). FABMS (positive-ion, m/z) 657 (M+H)+. Anal. Calcd
for C32H32O15ꢂ0.1CHCl3: C, 57.67; H, 4.84. Found: C, 57.75; H,
4.70.
To a stirred solution of 6 (40 mg, 0.04 mmol) in dry MeOH
(1 mL), a 25% NaOMe methanolic solution (0.2 mL) was added
dropwise at room temperature, and the mixture was stirred for
1 h. Dowex 50Wx8 (H+) resin was added to the stirred reaction
mixture until the solution pH was neutral. The mixture was filtered
and the filtrate was evaporated in vacuo to give 2 (21.1 mg, 91%) as
a yellow amorphous powder. 1H NMR spectroscopy of products 2,

1830
S. Sato, T. Koide / Carbohydrate Research 345 (2010) 1825–1830
4.9. 3,5-Di-C-b-
phenone (12)
D
-(xylopyranosyl-glucopyranosyl)phloroaceto-
2.50 (each 3H, s, ArOAc ꢀ 3), 6.66 (1H, s, H3), 7.39 (2H, d, J 8.8,
H30,50), 8.07 (2H, d, H20,60), glucose moiety: 3.77 (1H, ddd, J 9.5,
4.0, 2.0, H5), 4.20 (1H, dd, J 12.7, 2.0, H6a), 4.28 (1H, dd, J 4.0,
12.7, H6b), 4.60 (1H, J 10.0, H1), 5.42 (1H, t, J 9.5, H3), 5.47 (1H,
t, J 9.5, H4), 5.74 (1H, t, J 9.5, H2), xylose moiety: 3.41 (1H, t, J
11.0, H5a), 4.18 (1H, dd, J 11.0, 5.6, H5b), 4.73 (1H, d, J 9.3, H1),
5.04 (1H, ddd, J 9.6, 5.6, 11.1, H4), 5.31 (1H, t, J 9.6, H3), 5.62
(1H, t, J 9.6, H2), 1.76, 1.88, 1.93, 1.99, 2.05, 2.08, 2.10 (each 3H,
s, OAc ꢀ 7). FABMS (positive-ion, m/z) 985 (M+H)+. Anal. Calcd
for C46H48O24: C, 56.10; H, 4.91. Found: C, 55.99; H, 4.83.
Synthesis and purification were performed in the same manner
as that used for 4: reaction solvent system, 2:1 EtOH–H2O; reflux-
ing time, one day. ½a D22
ꢃ
+87.6 (c 1.005, MeOH). IR (KBr)
m 3369,
2923, 1701, 1622 cmꢁ1
.
1H NMR (DMSO-d6) d 2.58 (3H, s, Ac),
9.07 (1H, br s, OH), 11.50 (1H, s, OH), 12.0 (1H, br s, OH), (xylose
moiety) 3.11 (t, J 10.8, H5a), 3.16 (1H, t, J 8.9, H3), 3.45 (1H, ddd,
J 10.8, 8.9, 5.6, H4), 3.59 (1H, t, J 8.9, H2), 3.84 (1H, dd, J 5.6,
10.8, H5b), 4.72 (1H, d, J 9.8, H1), glucose moiety: 3.25 (1H, t, J
8.0, H3), 3.26 (1H, m, H6a), 3.32 (1H, t, J 9.0, H4), 3.43 (1H, m,
H5), 3.59 (1H, m, H6b), 4.56 (1H, d, J 9.6, H1), 4.74 (1H, br t, 6-
OH), 4.93 (1H, d, OH), 4.99 (2H, br t, OH ꢀ 2), 5.04 (1H, d, OH).
13C NMR (DMSO-d6) d sugar moiety: 60.03, 69.22, 69.73, 70.63,
71.70, 72.57, 75.10, 75.61, 77.76, 78.48, 81.29; 104.03, 104.50,
and 105.19 (C2, 4, 6), 161.7 (br), 161.06, and 161.58 (C1, 3, 5),
33.31 and 203.85 (Ac). FABMS (negative-ion, m/z) 461 (MꢁH)ꢁ.
Anal. Calcd for C19H26O13ꢂH2O: C, 47.49; H, 5.89. Found: C, 47.19;
H, 5.52.
4.13. 6-C-b-
trihydroxyflavone, vicenin-1 (1)
D-Xylopyranosyl-8-C-b-D
-glucopyranosyl-40,5,7-
½
a 2D2
ꢃ
+41.3 (c 0.450, MeOH). IR (KBr)
.
m 3367, 2921, 1653,
1575 cmꢁ1 1H NMR (DMSO-d6 + D2O, at 80 °C) d 3.64 (1H, br d, J
12.0), 3.91 (1H, dd, J 5.3, 10.9), 4.65 (1H, d, J 8.8), 4.78 (1H, dd, J
9.8, 14.7), 6.69 (1H, s, H3), 6.93 (2H, d, J 8.5, 30,50-H), 7.93 (2H, d,
J 8.5 Hz, H-20,60), 9.19 (1H, br s, 7-OH), 10.12 (1H, br s, 40-OH),
13.67 (1H, s, 50-OH). FABMS (positive-ion, m/z) 565 (M+H)+. Anal.
Calcd for C26H28O14ꢂ1.2H2O: C, 53.27; H, 5.24. Found: C, 53.04; H,
5.26.
4.10. 2,4,6-Tri-O-benzyl-3,5-di-C-b-
D-(xylopyranosyl-gluco-
pyranosyl)phloroacetophenone (13)
References
½
a 2D2
ꢃ
ꢁ27.4 (c 0.540, MeOH). IR (KBr)
m 3400, 2921, 2883, 1701,
1577 cmꢁ1 1H NMR (DMSO-d6 + D2O, at 120 °C) d 2.47 (3H, s, Ac),
.
1. Maurice, J. C-Glycosylflavonoids. In The Flavonoids; Harborne, J. B., Ed.;
Chapman and Hall: London, 1994; pp 57–93.
4.75 (2H, d, J 10.7, PhCH2), 4.84 and 5.13 (each 1H, d, J 10.2 and
10.7, PhCH2), 5.27 (2H, br s, PhCH2), glucose moiety: 3.17 (1H, t, J
8.8, H4), 3.20 (1H, t, J 8.3 H3), 3.21 (1H, m, H5), 3.49 (1H, dd, J
5.8, 11.5, H6a), 3.72 (1H, dd, J 2.0, 11.7, H6b), 4.24 (1H, t, J 8.8,
9.3, H2), 4.68 (1H, d, J 9.7, H1), xylose moiety: 3.08 (1H, t, J 11.0,
10.5, H5a), 3.14 (1H, t, J 9.0, H3), 3.32 (1H, ddd, J 5.3, 9.5, 10.0,
H4), 3.87 (1H, dd, J 5.4, 11.0, H5b), 4.15 (1H, t, J 9.0, 9.2, H2),
4.60 (1H, d, J 9.7, H1). FABMS (positive-ion, m/z) 733 (M+H)+. Anal.
Calcd for C40H44O13ꢂ0.5H2O: C, 64.76; H, 6.13. Found: C, 64.71; H,
6.24.
2. (a) Zavodnik, L. B. Radiat. Biol. Radiol. 2003, 43, 432–438; (b) Zavodnik, L. B.;
Zavodnik, I. B.; Lapshina, E. A.; Shkodich, A. P.; Bryszewska, M.; Buko, V. V.
Biochemistry (Moscow) 2000, 65, 946–951; (c) Lin, R. C.; Li, T. K. Am. J. Clin. Nutr.
1998, 68, 1512S; (d) Kawaguchi, K.; Melloalves, S.; Watanabe, T.; Kikuchi, S.;
Satake, M.; Kumazawa, Y. Planta Med. 1998, 329, 855–859; (e) Matsubara, Y.;
Suekuni, H.; Honda, S.; Kakehi, K.; Murakami, T.; Okamoto, K.; Miyake, H. Jpn.
Heart J. 1980, 21, 583; (f) Iizuka, Y.; Murakami, T.; Matsubara, Y.; Yokoi, K.;
Okamoto, K.; Yokoi, K. Agric. Biol. Chem. 1986, 50, 781; (g) Matsubara, Y.;
Sawabe, A. J. Synth. Org. Chem. Jpn. 1994, 52, 318–327; (h) Kawasaki, M.;
Hayashi, T.; Arisawa, M.; Morita, N.; Berganza, L. H. Phytochemistry 1988, 27,
3709–3711; (i) Ohsugi, T.; Nishida, R.; Fukami, H. Agric. Biol. Chem. 1985, 49,
1897–1900.
3. (a) Frick, W.; Schmidt, R. R. Liebigs Ann. Chem. 1989, 565–570; (b) Mahling, J.-
A.; Jung, K.-H.; Schmidt, R. R. Liebigs Ann. 1995, 461–466; (c) Kumazawa, T.;
Ohki, K.; Ishida, M.; Sato, S.; Onodera, J.-I.; Matsuba, S. Bull. Chem. Soc. Jpn. 1995,
68, 1379–1384; (d) Kumazawa, T.; Minatogawa, T.; Matsuba, S.; Sato, S.;
Onodera, J.-i. Carbohydr. Res. 2000, 329, 507–513; (e) Kumazawa, T.; Kimura, T.;
Matsuba, S.; Sato, S.; Onodera, J.-i. Carbohydr. Res. 2001, 334, 183–193; (f) Lee,
D. Y. W.; Zhang, W.-Y.; Karnati, V. V. R. Tetrahedron Lett. 2003, 44, 6857–6859;
(g) Oyama, K.-i.; Kondo, T. J. Org. Chem. 2004, 69, 5240–5246; (h) Sato, S.; Hiroe,
K.; Kumazawa, T.; Onodera, J.-i. Carbohydr. Res. 2006, 341, 1091–1095.
4. Sato, S.; Akiya, T.; Nishizawa, H.; Suzuki, T. Carbohydr. Res. 2006, 341, 964–970.
5. Sato, S.; Akiya, T.; Suzuki, T.; Onodera, J.-i. Carbohydr. Res. 2004, 339, 2611–
2614.
6. Yasukawa, K.; Kaneko, T.; Yamanouchi, S.; Takido, M. Yakugaku Zasshi 1986,
106, 517–519.
7. Seikel, M. K.; Chow, J. H. S.; Felman, L. Phytochemistry 1966, 5, 439–455.
8. Jay, M.; Ismaili, A. Phytochemistry 1989, 28, 3035–3037.
9. Johnson, R. H.; Wallace, J. W. Biochem. Syst. Ecol. 1988, 16, 521–523.
10. Shammas, G.; Couladi, M. Sci. Pharm. 1988, 56, 277–281.
11. Porter, P. L.; Wallace, J. W. Biochem. Syst. Ecol. 1988, 16, 261–262.
12. Seetharamamma, B.; Rao, C. V.; Gunasekar, D. Indian J. Nat. Prod. 1989, 5, 22.
13. Chaboud, A.; Raynaud, J.; Dellamonica, G. Pharm. Acta Helv. 1989, 64, 16–18.
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16. (a) Voigtlaender, H.-W.; Haertner, H. Arch. Pharm. 1983, 316, 3, 219–222; (b)
Lee, Y.-J.; Wu, T.-D. J. Chin. Chem. Soc. 2001, 48, 201–206.
17. (a) Kumazawa, T.; Assahi, N.; Matsuba, S.; Sato, S.; Furuhata, K.; Onodera, J.-i.
Carbohydr. Res. 1998, 308, 213–216; (b) Kumazawa, T.; Chiba, M.; Matsuba, S.;
Sato, S.; Onodera, J.-i. Carbohydr. Res. 2000, 328, 599–603; (c) Sato, S.;
Kumazawa, T.; Watanabe, K.-i.; Matsuba, S.; Onodera, J.-i. Carbohydr. Res.
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Carbohydr. Chem. 2008, 27, 86–102.
4.11. 2,4,6-Tri-O-benzyl-3,5-di-C-b-
pyranosyl)-1-[3-(p-benzyloxyphenyl)propenoyl]benzene (14)
D-(xylopyranosyl-gluco-
½
a 2D2
ꢃ
ꢁ22.9 (c 0.515, MeOH). IR (KBr)
m 3400, 2921, 2879, 1624,
1595, 1577, 1508 cmꢁ1. 1H NMR (DMSO-d6 + D2O, at 120 °C) d 4.77
(2H, d, J 9.8, PhCH2), 4.88 and 5.10 (each 1H, d, J 10.7, PhCH2), 5.16
(2H, s, 40-PhCH2), 5.30 (2H, br s, PhCH2), 6.99 (1H, d, J 16.1, trans-
vinyl H), 7.03 (1H, 2H, d, J 8.8, H30,50), 7.45 (1H, m, trans-vinyl H),
7.55 (1H, 2H, d, J 8.8, H20,60), 7.26–7.57 (20H, m, ArH), glucose moi-
ety: 3.16 (1H, t, J 9.2, H4), 3.23 (1H, m, H5), 3.23 (1H, t, J 9.5, H3),
3.50 (1H, dd, J 5.3, 11.9, H6a), 3.73 (1H, dd, J 1.7, 11.9, H6b), 4.25
(1H, t, J 9.2, H2), 4.71 (1H, d, J 9.7, H1), xylose moiety: 3.10 (1H,
t, J 10.6, H5a), 3.17 (1H, t, J 9.0, H3), 3.32 (1H, ddd, J 5.1, 10.0,
10.0, H4), 3.88 (1H, dd, J 5.3, 10.9, H5b), 4.16 (1H, t, J 9.0, H2),
4.63 (1H, d, J 9.7, H1). FABMS (positive-ion, m/z) 927 (M+H)+. Anal.
Calcd for C54H54O14ꢂ2H2O: C, 67.34; H, 6.08. Found: C, 67.58; H,
6.36.
4.12. 6-C-b-
trihydroxyflavone deca-acetate (15)
D-Xylopyranosyl-8-C-b-D
-glucopyranosyl-40,5,7-
½
a 1D9
ꢃ
+16.6 (c 0.650, MeOH). IR (KBr)
m 2943, 2866, 1755, 1653,
1604, 1508 cmꢁ1 1H NMR (CDCl3) d aglycon moiety: 2.35, 2.48,
.