Synthesis of galloyl-substituted procyanidin B4 series, and their DPPH radical scavenging activity and DNA polymerase inhibitory activity

Article abstract of DOI:10.3987/COM-05-S(T)11

Synthesis of galloyl-substituted procyanidin B4 series, 3-O-gallate, 3″-O-gallate and 3,3″-di-O-gallate, is described. Condensationof the electrophile derived from (+)-catechin with the nucleophile derived from (-)-epicatechin the presence of TMSOTf as a

Full text of DOI:10.3987/COM-05-S(T)11

HETEROCYCLES, Vol. 67, No. 1, 2006
175
HETEROCYCLES, Vol. 67, No. 1, 2006, pp. 175 - 188. © The Japan Institute of Heterocyclic Chemistry
Received, 13th May, 2005, Accepted, 13th July, 2005, Published online, 15th July, 2005. COM-05-S(T)11
SYNTHESIS OF GALLOYL-SUBSTITUTED PROCYANIDIN B4 SERIES,
AND THEIR DPPH RADICAL SCAVENGING ACTIVITY AND DNA
1
POLYMERASE INHIBITORY ACTIVITY
1
2
3
3
Hironori Sakuda, Akiko Saito, * Yoshiyuki Mizushina, Hiromi Yoshida,
4
1
Akira Tanaka, and Noriyuki Nakajima *
1
Biotechnology Research Center, Toyama Prefectural University
2
3
Biotechnology Center, Toyama Prefecture, Kosugi, Toyama 939-0398, Japan
Department of Nutritional Science, Kobe-Gakuin University, High Technology
Research Center, Kobe-Gakuin University, Nishi-ku, Kobe, Hyogo 651-2180,
Japan
4
Department of Bioresources Science, College of Technology, Toyama Prefectural
University, Kosugi, Toyama 939-0398, Japan
E-mail: nori@pu-toyama.ac.jp
Abstract – Synthesis of galloyl-substituted procyanidin B4 series, 3-O-gallate,
3
”-O-gallate and 3,3”-di-O-gallate, is described. Condensation of the electrophile
derived from (+)-catechin with the nucleophile derived from (-)-epicatechin in the
presence of TMSOTf as a catalyst gave procyanidin B4 3-O-gallate and
3
3
,3”-di-O-gallate in good yields. Procyanidin B4 3”-O-gallate and procyanidin B3
''-O-gallate were synthesized by the DCC method. Their DPPH radical
scavenging activity and DNA polymerase inhibitory activity were also
investigated. The results indicated that the presence of the galloyl moiety of these
compounds is very important for both activities.
INTRODUCTION
Gallic acid-substituted compounds are known as one of the strongest bioactive groups among the
polyphenols. Many research groups have reported the isolation and bioactivities of various types of
2
,3
galloyl compounds, and their strong bioactivities have recently received increasing attention. For
example, it is known that epigallocatechin-3-O-gallate (EGCG), the major polyphenol in green tea which
belongs to the flavan-3-ol group, has protective effect against a variety of cancer types, such as lung,

176
HETEROCYCLES, Vol. 67, No. 1, 2006
4
prostate and breast. In more recent research, the receptor that mediates the anticancer activity of EGCG
5
was identified. We have been interested in the strong antioxidant activity of proanthocyanidins caused by
6
the reaction with one-electron oxidants (free-radical scavenging activity), and we started a synthetic
study of proanthocyanidins to investigate their structure-activity relationships (SAR). Although their SAR
is most important, it has not been proved yet, because the presence of a large number of structurally
similar isomers in the plants makes it very difficult to purify individual compounds, and thus to supply
extremely pure compounds necessary for biological assay. Therefore, we decided to provide the pure
compounds by developing stereoselective synthesis.
Many reports on structural determination, biological activities and semi-synthesis of procyanidin
7
oligomers have been published thus far, but few studies concerning substituted oligomers have appeared.
In the last three years, we have reported several synthetic studies of procyanidins based on both
1
,8
9
intermolecular and intramolecular condensation method. The stereoselective synthesis of procyanidin
6
,8a-c
8d,e
dimers,
trimers consisting of (+)-catechin (1) and (-)-epicatechin (2) was achieved and their
1
b,8e
1
bioactivities including antioxidant activity in the TBA methods,
DPPH radical scavenging activity,
8
c,e
the Maillard reaction inhibitory activity, were investigated. Very recently, we reported an effective
systematic synthesis of galloyl-substituted procyanidin B1-B3 series (B1 series: 11-14, B2 series: 15-18,
and B3 series: 3, 4 and 6) with a simple condensation method using TMSOTf as a catalyst, and also
1
described their antioxidant activity and DNA polymerase inhibitory activities. In this report, we
undertook a synthesis of the galloyl-substituted analogues, procyanidin B4, procyanidin B4 3-O-gallate
(
8), procyanidin B4 3”-O-gallate (9), procyanidin B4 3,3''-di-O-gallate (10), and procyanidin B3 3”-O-
gallate (5). This is the final report concerning SAR for the [4-8]-condensed procyanidin B series. We
summarized which combination between (+)-catechin (1) and (-)-epicatechin (2) possessing the gallate-
substituent at the C3-position was the most appropriate for more prominent biological activity. We
describe herein the details of the results obtained by the assays of the procyanidin B3/B4 congeners (5, 7-
1
0) regarding DPPH radical scavenging activity and inhibitory activity against DNA polymerases.
RESULTS AND DISCUSSION
Synthesis of galloyl-substituted procyanidin B4 series.
We report here a synthesis of galloyl-substituted procyanidin B4 series including procyanidin B4 3-O-
gallate (8) and procyanidin B4-3,3”-di-O-gallate (10) by using our condensation methodology, in addition,
procyanidin B3 3”-O-gallate (5) and procyanidin B4 3”-O-gallate (9) by the DCC method to clarify the
relationships between the structure and biological activities.

HETEROCYCLES, Vol. 67, No. 1, 2006
177
OH
OH
OH
HO
O
HO
O
OH
OH
OH
OH
OH
1: (+)-catechin
2: (-)-epicatechin
OH
OH
OH
1
8
B
HO
O
2
HO
O
OH
A
C
3
6
4
OR1
OR1
OH
OH
OH
OH
HO
OH
HO
1"
8"
E
O
2"
O
OH
3"
D
F
6"
OR2
4"
OR2
OH
OH
3
4
5
6
: R = R = H, procyanidin B3
7: R = R = H, procyanidin B4
1 2
8: R = galloyl, R = H
1 2
9: R = H, R = galloyl
1 2
1
2
: R = galloyl, R = H
1
2
: R = H, R = galloyl
1
2
: R = R = galloyl
10: R = R = galloyl
1
2
1
2
OH
OH
OH
OH
HO
O
HO
O
OR1
O
OR1
O
OH
OH
OH
OH
OH
HO
OH
HO
OR2
OR2
OH
OH
1
1
1
1
1: R = R = H, procyanidin B1
15: R = R = H, procyanidin B2
16: R = galloyl, R = H
1 2
17: R = H, R = galloyl
1 2
18: R = R = galloyl
1 2
1 2
1
2
2: R = galloyl, R = H
1
2
3: R = H, R = galloyl
1
2
4: R = R =galloyl
1
2
Figure 1. Structure of procyanidin dimers consisting from (+)-catechin (1) and (-)-epicatechin (2)
Synthesis of 8 and 10 was achieved as shown in Scheme 1. The electrophile (19) was condensed with
nucleophile (20) in the presence of TMSOTf as a catalyst at -20˚C to give undecabenzyl procyanidin
B43-O-gallate (22) in 89% yield. Similarly, tetradecabenzyl-procyanidin B4 3,3”-di-O-gallate (23) was
obtained by the condensation of electrophile (19) with nucleophile (21) under the same conditions in 93%
yield. The following deprotection and purification yielded pure procyanidin B4 3-O-gallate (8) and 3,3”-
di-O-gallate (10) in 31% and 67% yields, respectively. The structure confirmation of these compounds

178
HETEROCYCLES, Vol. 67, No. 1, 2006
1
1
9
9
+
+
20
21
OBn
OBn
BnO
O
OG
OBn O(CH ) OCH CH
a
2
2
2
3
1
9
OR3
OR3
OBn
OBn
R O
O
3
BnO
O
OR1
O
OR
OR3
OR3
OR3
OBn
R O
20: R = H
1: R = G
3
2
OR2
OR3
OR3
OR3
OR3
2
2
8
1
2: R = G, R = H, R = Bn, 89%
G =
1
2
3
b
3: R = R = G, R = Bn, 93%
1
2
3
O
: R = G, R = H, R = H, 31%
b
1
2
3
0: R = R = G, R = H, 67%
1
2
3
Reagents: (a) TMSOTf, CH Cl , -20˚C; (b) 20% Pd(OH) /C, H , THF/MeOH/H O.
2
2
2
2
2
Scheme 1. Synthesis of procyanidin B4 3-O-gallate and procyanidin B4 3,3''-di-O-gallate.
was accomplished by the NMR measurement even though the NMR spectra of these compounds exhibit
1
0
1
multiplicity due to rotational isomerism. The new compounds (8 and 10) gave satisfactory NMR ( H
1
3
NMR, C NMR) and FAB-MS data.
Benzylated procyanidin B3 3”-O-gallate (26) and benzylated procyanidin B4 3”-O-gallate (27) were also
synthesized using the DCC method as shown in Scheme 2. The TMSOTf-catalyzed condensation method
is inapplicable to 24 and 25, because the condensation using an electrophile (28) without the ester group
at the C-3 position leads to formation of a mixture of 3,4-trans and 3,4-cis dimers with low
8
a,b
stereoselectivity. Condensation of octabenzyl-procyanidin B3 (24) and octabenzyl-procyanidin B4 (25)
1
1
with 3,4,5-tri-O-benzylgallic acid by the DCC method gave 26 and 27 in 26% and 74% yields,
respectively. Hydrogenation of the benzyl groups and purification gave pure 5 and 9 in moderate yields.
1
2
The procyanidin B1 3-O-gallate (9) is reported as a natural product isolated from green tea leaf. The
2
5
optical rotation value of the synthetic 9, [α] = -279.1° (c 0.095, acetone), is identical with those of the
D
2
2
natural product, [α] = -255.7° (c 0.56, acetone). The structure confirmation was accomplished by the
D
NMR measurement in the presence of rotational isomers.

HETEROCYCLES, Vol. 67, No. 1, 2006
179
DPPH radical scavenging activity
1
Proanthocyanidins are known as strong antioxidants and radical scavengers. In our previous papers, we
investigated DPPH radical scavenging activity of procyanidin B1-B3 series including galloyl-substituted
OR3
OR3
OBn
OBn
R O
O
3
BnO
O
OH
O
OH
OR3
OR3
OR3
OBn O(CH ) OCH CH
2
2
2
3
R O
3
28
R2
R1
OR3
2
2
2
4: R = OH, R = H, R = Bn
1 2 3
OR3
a
5: R = H, R = OH, R = Bn
1
2
3
6: R = OG, R = H, R = Bn, 26%
a
b
1
2
3
G =
OR3
OR3
b
27: R = H, R = OG, R = Bn, 74%
1 2 3
5
9
O
: R = OG, R = H, R = H, 54%
1 2 3
: R = H, R = OG, R = H, 53%
1
2
3
Reagent: (a) DCC, DMAP, CH Cl ; (b) 20 % Pd(OH) /C, H , THF/MeOH/H O.
2
2
2
2
2
Scheme 2 Synthesis of procyanidin B3 3''-O-gallate and procyanidin B4 3''-O-gallate.
compounds, and it became apparent that the procyanidin B3 series acted as radical scavengers with a
different mode from the procyanidin B1 and B2 series. The radical scavenging ability of the procyanidin
B3 series was much weaker than that of the procyanidin B1 and B2 series. Then, we examined the effect
of the procyanidin B3 3''-O-gallate (5) and the galloyl-substituted procyanidin B4 series (7-10) that were
constituted of 1 and 2, on DPPH radical scavenging activity. The results are shown in Table 1. As a
control compound, DL-α-tocopherol was used (Entry 6).
Table 1. DPPH radical scavenging activity
Entry
Compound
SC (µM)
50
1
2
3
4
5
6
5
7
8
9
10
1.1
2.0
0.9
0.8
0.9
17
DL-α−Tocopherol
The SC values (concentration of 50% scavenging activity) of those compounds were 1.1 (5), 2.0 (7), 0.9
5
0
(
8), 0.8 (9) and 0.9 µM (10), respectively. It appeared that the radical scavenging activity tended to be

180
HETEROCYCLES, Vol. 67, No. 1, 2006
stronger with the presence of a galloyl group. The SC values of the procyanidin B1 series (11-14),
5
0
procyanidin B2 series (15-18) and procyanidin B3 series (3, 4 and 6) were described in a previous paper
as 1.3 (11), 0.8 (12), 0.7 (13), 0.6 (14), 1.2 (15), 0.8 (16), 0.6 (17), 0.6 (18), 1.3 (3), 3.2 (4) and 1.1 µM
1
(
6), respectively. As compared with the results in Table 1, the procyanidin B1/B2 series scavenged
DPPH radical much more strongly than the procyanidin B3/B4 series. These results suggest that the
galloyl group of the procyanidin B1/B2 series is more effective for radical scavenging activity than that of
the procyanidin B3/B4 series. It appeared that the presence of a (-)-epicatechin unit was very important
and the (-)-epicatechin unit on the upper position of the dimer was more effective for radical scavenging
activity by comparing B4 series with B1 series. In addition, it was suggested that the galloyl group not at
the C3-position, but at the C3”-position was more effective.
Effects of galloyl-substituted compounds on the inhibitory activities against mammalian DNA
polymerase α and β
DNA polymerases, especially DNA polymerase α which is a DNA replicative polymerase, are regarded
as the target of some anticancer drugs, because DNA polymerases play central roles in DNA replication
which is indispensable for the proliferation of cancer cells. Monomeric flavan-3-O-gallates, (-)-
epicatechin-3-O-gallate, (-)-epigallocatechin-3-O-gallate, etc., that occur in green tea, are known as
1
3
inhibitors of DNA and RNA polymerases, and flavan-3-ols without a galloyl group were not effective
for this polymerase inhibitory activity. These facts allowed us to expect galloyl-substituted procyanidin
dimers to be effective inhibitors of DNA polymerases. In a previous paper, we described the ability of the
procyanidin B1-B3 series as DNA polymerase inhibitor. The IC values (concentration of 50% inhibitory
5
0
activity) for DNA polymerase a of 11-18, 3, 4 and 6 were 25.4 (11), 0.72 (12), 0.89 (13), 0.23 (14), 24.0
1
4
15ꢀ
(
15), 0.70 (16), 0.85 (17), 0.24 (18), 36.4 (3), 0.26 (4) and 0.12 µM (6) , respectively. Interestingly, the
di-O-gallate compounds (6, 14 and 18) have inhibitory ability against DNA polymerase β. The IC50
1
4
values are 125 (6), 89 (14) and 102 µM (18), respectively. In contrast, the des- and mono-O-gallate
compounds (11-13, 15-17, 3 and 4) did not inhibit DNA polymerase β.
Table 2 shows the IC values of synthesized compounds (5 and 7-10) against calf DNA polymerase a and
5
0
rat DNA polymerase β. The IC values of those compounds were 0.96 (5), 24.6 (7), 0.66 (8), 0.70 (9) and
5
0
0
.09 µM (10), respectively. Procyanidin B4 3,3”-di-O-gallate (10) inhibited DNA polymerase a very
strongly and is the strongest inhibitor against DNA polymerase a among the galloyl-dimer series. The di-
O-gallate (10) inhibits DNA polymerase β at 98 µM in a manner similar to the procyanidin B1/B2 series.
1
As mentioned in our previous papers, the presence of a gallate moiety is very important for DNA
polymerase inhibitory activity, which tended to be stronger as the number of galloyl groups increased.

HETEROCYCLES, Vol. 67, No. 1, 2006
181
Table 2. IC values of enzymatic inhibition against
5
0
mammalian DNA polymerase α and β
Entry
Compound
IC values (µM)
50
DNA polymerase α DNA polymerase β
1
2
3
4
5
5
7
8
9
10
0.96
24.6
0.66
0.70
0.09
>500
>500
>500
>500
98
Conclusion
In this paper, we have reported the details of the synthesis of the galloyl-substituted procyanidin B4 series,
-O- and 3”-O-gallic acid esters, and 3”-O-galloyl procyanidin B3. Their ability of DPPH radical
3
scavenging activity and DNA polymerase inhibitory activity was also investigated. The results indicated
that the gallate group of these compounds was very important for both activities. The radical scavenging
activity of the galloyl-substituted procyanidin B1/B2 series was more effective than that of the
procyanidin B3/B4 series. It appeared that the presence of the (-)-epicatechin unit at the upper part of the
dimer was very important for its ability by comparing the inhibitory effect for the procyanidin B4 series
with the procyanidin B1 series. It was also suggested that the galloyl group not at the C3-position, but at
the C3''-position was more effective. Procyanidin B4 3,3”-di-O-gallate (10) was the strongest inhibitor
against DNA polymerase α among the procyanidin B1-B4 series and had the ability to inhibit DNA
polymerase β in a manner similar to the procyanidin B1-B3 series. The presence of a gallate moiety is
very important for DNA polymerase inhibitory activity, which tended to be stronger as the number of
galloyl groups increased.
EXPERIMENTAL
1
Synthesis: Optical rotation was measured with a Horiba SEPA-300 spectrometer. H-NMR spectra were
measured with JEOL JNMLA400 spectrometer. MS spectra were recorded with a JEOL JMS-AX500
instrument. HPLC purification was carried out on a Mightysil® RP-18 GP column (Kanto Chemical Co.
Inc, Japan; 250 x 20 mm, 5 mm) using the solvents (A) 0.05% CF CO H in CH CN and (B) 0.05%
3
2
3
CF CO H in H O. Elution was done with a linear gradient 5 to 100% A in 40 min (flow rate, 4.0
3
2
2
mL/min).
[
(
4,8]-2,3-trans-3,4-trans:2,3-cis-Octa-O-benzyl-(+)-catechin-(-)-epicatechin-3-O-(tri-O-benzyl)gallate
22). To a solution of 19 (30.0 mg, 0.026 mmol) and 20 (67.2 mg, 0.10 mmol) in CH Cl (30 mL) was
2
2
added dropwise TMSOTf (0.052 mL, 0.026 mmol, 0.5 M solution in CH Cl ) at -20˚C. After stirring for 5
2
2

182
HETEROCYCLES, Vol. 67, No. 1, 2006
min, the pale yellow reaction mixture was quenched with sat. sodium hydrogen carbonate. The aq.
solution was extracted with CHCl and the organic phase was washed with water and brine, and dried
3
(
Na SO ). Filtration, concentration and preparative silica gel TLC purification (benzene-AcOEt, 20:1)
2 4
2
5
1
afforded 40.0 mg (89%) of 22 as a colorless amorphous solid. [α] = -35.8° (c 0.40, CHCl ); H-NMR
D
3
(
(
400 MHz, CDCl , 0.59 : 0.41 mixture of rotational isomers) major isomer: 7.44-6.58 (37.17H, m), 6.265
3
0.59H, d, J = 2.2 Hz, 8), 6.256 (0.59, s, 6''), 6.19 (0.59H, d, J = 2.2 Hz, 6), 5.86 (0.59H, dd, J = 8.6, 9.2
Hz, 3), 5.14-4.39 (14.16H, m), 3.83 (0.59H, br, 3''), 3.38 (0.59H, br s, 2''), 2.69 (0.59H, d, J = 15.6 Hz, 4''),
.52 (0.59H, dd, J = 4.4, 15.6 Hz, 4''), 1.36 (0.59H, d, J = 9.5 Hz, OH); minor isomer: 7.44-6.58 (25.83H,
m), 6.28 (0.41H, d, J = 2.2 Hz), 6.27-6.26 (0.41H, m), 6.00 (0.41H, t, J = 10.0 Hz, 3), 5.83 (0.41H, s, 6''),
2
5
1
.16 (0.41H, d, J = 10.0 Hz, 2), 5.14-4.39 (9.83H, m), 4.14-4.17 (0.41H, br, 3''), 3.02-2.94 (0.82H, m, 4''),
1
3
.48 (0.41H, d, J = 6.5 Hz, OH); C-NMR (100 MHz, CDCl , 0.59 : 0.41 mixture of rotational isomers)
3
major isomer: 164.6, 158.2, 157.9, 156.9, 156.3, 155.6, 153.6, 152.4, 149.0 (x2), 148.5, 148.2, 142.4,
1
1
37.8-136.5 (Cx11), 131.4, 131.1, 128.9-126.5 (Cx29), 125.2, 120.9, 119.5, 114.9, 114.1, 113.8, 113.76,
11.8, 108.8, 108.7, 101.1, 95.0, 94.5, 91.5, 80.0 (2), 78.3 (2''), 75.0 (3), 71.8-69.7 (Cx10), 64.9 (3''), 35.1
(
4), 29.7 (4''); minor isomer: 164.3, 158.4, 158.2, 156.7, 156.4, 156.1, 153.3, 152.2, 148.9, 148.8, 148.7,
1
1
6
1
48.2, 142.1, 137.8-136.5 (Cx11), 131.5, 131.0, 128.9-126.5 (Cx29), 125.3, 120.6, 119.9, 114.9, 114.6,
13.9, 113.3, 110.7, 108.8, 108.1, 102.2, 95.3, 94.7, 91.7, 79.8 (2), 77.6 (2''), 75.0 (3), 71.8-69.7 (Cx10),
-
1
6.8 (3''), 35.3 (4), 29.4 (4''); IR (neat, cm ) 3065 (w), 3032 (w), 2926 (w), 1717 (m), 1590 (m), 1514 (w),
516 (m), 1499 (m), 1456 (m), 1375 (m), 1331 (m), 1262 (s), 1109 (s), 1028 (s), 911 (w), 853 (w), 812
+
+
(
w); FAB-MS (m/z) 1745 (24), 1744 ([M+Na] , 29), 1724 (70), 1723 (98), 1722 ([M+H] , 100), 1459
+
(
45), 1281 (73), 1190 (100), 1100 (56), 857 (66); FAB-HRMS calcd for C H O [M+H] , 1721.6777;
1
14 97 16
found: 1721.6737.
[
4,8]-2,3-trans-3,4-trans:2,3-cis-Octa-O-benzyl-(+)-catechin-(-)-epicatechin-3,3''-di-O-(tri-O-
benzyl)gallate (23). To a solution of 19 (30.0 mg, 0.026 mmol) and 21 (112 mg, 0.10 mmol) in CH Cl2
2
(
30 mL) was added dropwise TMSOTf (0.052 mL, 0.026 mmol, 0.5 M solution in CH Cl ) at -20˚C. After
2 2
stirring for 5 min, the pale yellow reaction mixture was quenched with sat. sodium hydrogen carbonate.
The aq. solution was extracted with CHCl and the organic phase was washed with water and brine, and
3
dried (Na SO ). Filtration, concentration and silica gel column chromatography (benzene and then CHCl )
2
4
3
2
5
1
afforded 52.0 mg (93%) of 23 as a colorless amorphous solid. [α] = -108.4° (c 1.52, CHCl ); H-NMR
D
3
(
(
400 MHz, CDCl , 0.67 : 0.33 mixture of rotational isomers) major isomer: 7.43-6.68 (52.26H, m), 6.63
3
0.67H, d, J = 8.3 Hz), 6.56 (0.67H, dd, J = 1.7, 8.3 Hz), 6.24-6.15 (0.67H, m, 6 and 8), 5.99 (0.67H, t, J
=
9.1 Hz, 3), 5.86 (0.67H, s, 6''), 5.67-5.60 (0.67H, br s, 2''), 5.14 (0.67H, d, J = 9.1 Hz, 4), 5.07-4.35

HETEROCYCLES, Vol. 67, No. 1, 2006
183
(
19.43H, m), 3.26 (0.67H, dd, J = 6.1, 18.5 Hz, 4''), 3.06 (0.67H, d, J = 18.5 Hz, 4''); minor isomer: 7.43-
6
6
.68 (26.07H, m), 6.31 (0.33H, d, J = 8.3 Hz), 6.26 (0.33H, d, J = 2.2 Hz, 8), 6.21 (0.33H, s, 6''), 6.24-
.15 (0.33H, m, 6), 6.08 (0.33H, dd, J = 7.5, 10.0 Hz, 3), 5.25-5.18 (0.66H, m, 4 and 3''), 5.07-4,30 (9.9H,
1
3
m), 2.74 (0.33H, dd, J = 4.9, 16.8 Hz, 4''), 2.61 (0.33H, dd, J = 5.8, 16.8 Hz, 4''); C-NMR (100 MHz,
CDCl , 0.67 : 0.33 mixture of rotational isomers) major isomer: 165.4, 164.3, 158.4, 158.2, 156.7, 156.6,
3
1
1
1
1
1
1
6
1
55.7, 153.6, 152.5, 152.2, 148.93, 148.86, 148.7, 143.4, 142.1, 137.8-136.4 (Cx17), 132.5, 131.3, 131.0,
30.9, 129.0-126.6 (Cx31), 125.34, 125.25, 125.0, 120.6, 114.9, 114.4, 113.2, 111.1, 110.2, 108.7, 108.2,
01.8, 95.2, 94.7, 91.6, 79.8, 77.2, 75.06, 75.04, 74.8, 72.2-69.2 (Cx11), 35.3, 26.1; minor isomer: 165.6,
64.8, 158.2, 157.9, 157.1, 156.1, 155.5, 153.6, 152.3, 152.1, 148.9, 148.5, 148.0, 142.4, 142.1, 137.8-
36.4 (Cx17), 132.5, 131.3, 130.9, 130.5, 129.0-126.6 (Cx31), 125.5, 125.3, 125.0, 120.3, 114.97, 114.3,
13.4, 111.5, 108.9, 108.8, 108.4, 100.6, 95.0, 94.7, 91.2, 80.2, 77.6, 75.1, 75.0, 74.9, 72.2-69.2 (Cx10),
-
1
7.6, 34.9, 24.5; IR (neat, cm ) 3090 (w), 3065 (w), 3033 (m), 2934 (w), 2870 (w), 1717 (s), 1590 (s),
499 (s), 1455 (s), 1428 (s), 1375 (s), 1331 (s), 1215 (s), 1113 (s), 1028 (s), 911 (w), 857 (w), 812 (w);
+
+
FAB-MS (m/z) 2167 (16), 2166 ([M+Na] , 46), 2165 (12), 2143 ([M+H] , 11), 2070 (37), 1935 (34),
+
1
703 (69), 1613 (100), 1521 (64), 1236 (67); FAB-HRMS calcd for C H O Na [M+Na] , 2165.8114;
1
42 118 20
found: 2165.8071.
Procyanidin B4 3-O-gallate (8). A solution of 22 (49.0 mg, 28 mmol) in 22 mL of THF/ CH OH/H O
3
2
(
20/1/1) was hydrogenated over 20% Pd(OH) /C (5 mg) for 3 h at rt. Filtration and concentration afforded
2
a pale brown solid, which was purified by Sephadex® LH-20 column chromatography (CH OH) or
3
Cosmosil 75 C -OPN (NAKALAI TESQUE, INC.) column chromatography, and then HPLC
1
8
2
2
purification to give 6.3 mg (31%) of pure 8 as a pale blown amorphous solid; [α] = -44.4° (c 0.038,
D
1
CH OH) ; H-NMR (400 MHz, 10% D O in CD COCD , 0.72 : 0.28 mixture of rotational isomers) major
3
2
3
3
isomer: 6.84 (1.44H, s), 6.79 (0.72H, d, J = 1.7 Hz), 6.74 (0.72H, d, J = 1.7 Hz), 6.69 (0.72H, d, J = 8.3
Hz), 6.53 (0.72H, d, J = 8.3 Hz), 6.47 (0.72H, dd, J = 1.7, 8.3 Hz), 6.44 (0.72H, dd, J = 1.7, 8.3 Hz), 6.13
(
0.72H, dd, 8.7, 10.0 Hz, 3), 6.00 (0.72H, s, 6''), 5.97 (0.72H, d, J = 2.2 Hz, 8), 5.94 (0.72H, d, J = 2.2 Hz,
), 4.76 (0.72H, d, J = 8.7 Hz, 2), 4.65 (0.72H, d, J = 10.0 Hz, 4), 4.16-4.12 (0.72H, br, 3''), 4.02-3.55
0.72H, m, 2''), 2.80 (0.72H, dd, J = 4.7, 16.8 Hz, 4''), 2.62 (0.72H, dd, J = 2.7, 16.8 Hz, 4''); minor
isomer: 7.02-6.43 (2.25H, m), 6.09 (0.28H, dd, J = 7.8, 10.0 Hz, 3), 6.02 (0.28H, s, 6''), 5.87 (0.28H, d, J
2.2 Hz, 8), 5.85 (0.28H, d, J = 2.2 Hz, 6), 4.90-4.58 (0.56H, m), 4.12-4.07 (0.28H, 3''), 4.02-3.55
6
(
=
1
3
(
0.28H, m, 2''), 2.85-2.55 (0.26H, m, 4'') ; C-NMR (100 MHz, 10% D O in CD COCD 0.72 : 0.28
2 3 3,
mixture of rotational isomer) major isomer: 165.3, 157.7, 157.2, 155.9, 155.4, 154.7, 145.5, 145.1, 144.9,
44.8, 144.76, 131.3, 130.4, 121.6, 120.2, 119.5, 115.9, 115.4, 115.3, 114.6, 114.1, 109.7, 105.5, 100.9,
1

184
HETEROCYCLES, Vol. 67, No. 1, 2006
9
1
1
7.4, 96.6, 95.7 (Cx2), 81.3, 79.0, 72.9, 66.8, 64.2, 36.0, 28.6; minor isomer: 164.9, 157.0, 156.9, 156.0,
55.3, 154.1, 145.6, 145.4, 145.2 (Cx2), 145.1, 131.8, 130.6, 120.4, 119.1, 119.0, 116.1-113.9 (Cx5),
09.9, 105.0, 99.5, 97.1, 96.4, 95.4, 95.3, 81.6, 79.2, 73.3, 66.7, 64.1, 35.6, 28.7;ꢀFAB-MS (m/z) 755
+
+
(
7.8), 754 (12), 753 ([M+Na] , 40), 733 (5.0), 732 (10), 731 ([M+H] , 15), 677 (40), 619 (47), 575 (65),
+
5
31 (81), 487 (100); FAB-HRMS calcd for C H O Na[M+Na] , 753.1432; found: 753.1478.
3
7
30 16
Procyanidin B4 3,3''-di-O-gallate (10). A solution of 23 (90.0 mg, 0.042 mmol) in 22 mL of THF/
CH OH/H O (20/1/1) was hydrogenated over 20% Pd(OH) /C (5 mg) for 12 h at rt. Filtration and
3
2
2
concentration afforded a pale brown solid, which was purified by Sephadex® LH-20 column
chromatography (CH OH) column chromatography, and then HPLC purification to give 30.3 mg of pure
3
2
5
1
1
0 (0.034 mmol, 81%) as a pale brown amorphous solid. [α] = -376.4° (c 0.20, CH OH); H-NMR
D 3
(
400 MHz, 10% D O in CD COCD , rotational isomer was not observed) 6.90 (2H, s, 2'), 6.85 (2H, s, 2'),
2 3 3
6
.77 (1H, d, J = 1.7 Hz), 6.74 (1H, d, J = 1.7 Hz), 6.62 (1H, d, J = 8.3 Hz), 6.55 (1H, d, J = 8.3 Hz), 6.51
(
1H, dd, J = 1.7, 8.3 Hz), 6.33 (1H, dd, J = 1.7, 8.3 Hz), 6.21 (1H, d, J = 2.2 Hz, 8), 6.02 (1H, t, J = 10.0
Hz, 3), 6.00 (1H, d, J = 2.2 Hz, 6), 5.97 (1H, s, 6''), 5.38-5.33 (1H, m, 3''), 5.12 (1H, s, 2''), 4.87 (1H, d, J
9.3 Hz, 2), 4.74 (1H, d, J = 10.0 Hz, 4), 2.94 (1H, dd, J = 4.6, 15.9 Hz, 4''), 2.77 (1H, d, J = 15.9 Hz,
=
1
3
4
1
1
6
8
9
''); C-NMR (100 MHz, 10% D O in CD COCD ) 166.6, 165.4, 157.5, 157.0, 156.6, 155.8, 155.44,
2 3 3
55.40, 145.4 (x2), 145.4, 144.85, 144.77, 144.65, 138.8, 138.3, 130.6, 130.2, 121.6, 121.3, 120.1, 119.7,
15.9, 115.5, 115.3, 114.0, 110.2, 109.6, 105.6, 104.5, 99.3, 97.6, 96.7, 95.7, 81.2 (2), 77.8 (2''), 72.8 (3),
+
+
9.7 (3''), 36.0 (4), 26.7 (4''); FAB-MS (m/z) 906 (8.0), 905 ([M+Na] , 13), 883 ([M+H] , 10), 882 (20),
+
57 (25), 664 (52), 550 (45), 411 (100); FAB-HRMS calcd for C H O Na [M+Na] , 905.1541; found:
4
4
34 20
05.1511.
[
4,8]-2,3-trans-3,4-trans:2,3-trans-Octa-O-benzyl-(+)-catechin-(+)-catechin-3''-O-(tri-O-
benzyl)gallate (26). A solution of 24 (426 mg, 0.33 mmol) and 3,4,5-tri-O-benzylgallic acid (174 mg,
.40 mmol) in CH Cl (50 mL) was treated with DCC (73.4 mg, 0.40 mmol) and DMAP (5.00 mg) to
0
2
2
afford 146 mg (26%) of 24 as a colorless amorphous solid, and the 100 mg of starting material (26) was
2
4
recovered (23%) with 80 mg (14%) of 3-O-gallate and 101 mg (14%) of 3,3''-di-O-gallate. [α] = -37.5°
D
1
(
c 0.90, CHCl ); H-NMR (400 MHz, CDCl , 0.5 : 0.5 mixture of rotational isomers) major isomer: 7.45-
3
3
6
6
.77 (61.5H, m), 6.656 (0.5H, d, J = 1.7 Hz), 6.54 (0.5H, d, J = 8.3 Hz), 6.32 (0.5H, dd, J = 1.7, 8.3 Hz),
.25 (0.5H, s, D6''), 6.18 (0.5H, d, J = 2.2 Hz, 8), 6.14 (0.5H, d, J = 2.2 Hz, 8), 6.11 (0.5H, s, 6''), 6.09
(
0.5H, d, J = 2.2 Hz, 6), 5.99 (0.5H, d, J = 2.2 Hz, 6), 5.36-5.32 (0.5H, m, 3''), 5.13-4.48 (25H, m). 4.33-
.26 (1H, m, 2), 3.80 (0.5H, d, J = 9.3 Hz, 2''), 3.26 (0.5H, dd, J = 6.3, 16.3 Hz, 4''), 3.06 (0.5H, dd, J =
4

HETEROCYCLES, Vol. 67, No. 1, 2006
185
5
.2, 16.6 Hz, 4''), 2.85 (0.5H, dd, J = 7.3, 16.6 Hz, 4''), 2.52 (0.5H, dd, J = 9.0, 16.3 Hz, 4''), 1.556 (0.5H,
1
3
d, J = 3.4 Hz, OH), 1.50 (0.5H, d, J = 3.4 Hz, OH); C-NMR (100 MHz, CDCl , 0.5 : 0.5 mixture of
3
rotational isomers) 165.1, 164.8, 158.1, 157.9, 157.6, 157.4, 157.1, 157.0, 156.8, 155.6, 155.4 (x2), 154.0,
1
1
1
9
52.44, 152.40, 152.2, 149.2, 149.0 (x2), 149.98, 148.95, 148.85, 148.7, 148.5, 142.62, 142.56, 137.6-
36.5 (Cx20), 131.8, 131.7, 131.6, 130.7, 128.6-127.0 (Cx60), 125.2, 125.0, 121.2, 120.5, 120.2, 120.1,
14.9, 114.8, 114.6, 114.1, 113.7, 113.6, 113.5, 112.1, 109.1, 109.0, 108.6, 108.3, 102.1, 101.9, 94.8, 94.7,
4.2, 94.1, 91.54, 91.47, 82.04 (2), 81.97 (2), 77.8(2''), 77.7 (2''), 75.1, 75.0, 73.8(3), 73.0(3), 71.5-69.8
-
1
(
Cx22), 37.3 (4), 37.2 (4), 26.5 (4''), 24.5 (4''); IR (neat, cm ) 3569 (w), 3065 (m), 3032 (m), 2932 (m),
2
870 (m), 1952 (w), 1877 (w), 1811 (w), 1713 (s), 1589 (s), 1498 (s), 1420 (s), 1331 (s), 1264 (s), 1215
+
(
(
s), 1180 (s), 1028 (s), 910 (m), 854 (m); FAB-MS (m/z) 1746 (25), 1745 ([M+Na] , 44), 1744 (32), 1724
+
39), 1723 (50), 1722 ([M+H] , 25), 1284 (32), 1283 (48), 1282 (40), 1281 (32), 1280 (34), 1193 (39),
+
1
1
192 (55), 1191 (100), 1190 (98); FAB-HRMS calcd for C H O [M+H] , 1721.6777; found:
1
14 97 16
721.6697.
[
4,8]-2,3-trans-3,4-trans:2,3-cis-Octa-O-benzyl-(+)-catechin-(-)-epicatechin-3’’-O-(tri-O-
benzyl)gallate (27). A solution of 25 (290 mg, 0.22 mmol) and 3,4,5-tri-O-bebzylgallic acid (118 mg,
.27 mmol) in CH Cl (50 mL) was treated with DCC (55.7 mg, 0.27 mmol) and DMAP (5.00 mg) to
0
2
2
2
2
1
afford 280 mg (74%) of 27 as a colorless amorphous solid. [α] = -121.1° (c 0.32, CHCl ); H-NMR
D
3
(
(
400 MHz, CDCl , 0.94 : 0.06 mixture of rotational isomers) major isomer: 7.44-6.78 (56.4H, m), 6.86
3
0.94H, d, J = 8.3 Hz), 6.69 (0.94H, dd, J = 1.7, 8.3 Hz), 6.62 (0.94H, d, J = 8.3 Hz), 6.27 (0.94H, s, 6''),
6
.21 (0.94H, d, J = 2.2 Hz, 8), 6.11 (0.94H, d, J = 2.2 Hz, 6), 5.33-5.27 (0.94H, m, 3''), 5.13-4.45 (22.56H,
m), 4.36 (0.94H, t, J = 9.0 Hz, 3), 3.84 (0.94H, s, 2''), 2.98 (0.94H, d, J = 16.8 Hz, 4''), 2.77 (0.94H, dd, J
4.7, 16.8 Hz, 4''), 1.85 (0.94H, d, J = 2.7 Hz, OH); minor isomer: 7.44-6.45 (3.78H, m), 6.25-6.10
0.12H, m), 6.02 (0.06H, s, 6''), 5.58 (0.06H, br s, 3''), 5.13-4.17 (1.5H, m), 3.90 (0.06H, s, 2''), 3.25-3.05
=
(
(
1
3
0.12H, m, 4''), 1.6-1.2 (0.06H, m); C-NMR (100 MHz, CDCl , 0.94 : 0.06 mixture of rotational
3
isomers) major isomer: 165.2, 158.0, 157.8, 156.8, 155.8, 155.6, 152.3, 149.2, 148.9, 148.8, 148.4, 142.5,
1
1
7
3
1
4
37.5-136.6 (Cx10), 131.68, 131.65, 130.9, 128.8-127.2 (Cx30), 125.0, 121.2, 119.2, 114.7, 114.6,
13.30, 113.26, 111.9, 109.1, 108.5, 100.7, 94.8, 94.0, 91.5, 82.2, 75.0, 73.1, 71.3, 71.15, 71.12, 70.9,
-
1
0.8 (Cx2), 70.3, 70.2, 70.1, 70.0, 68.2, 38.7, 26.4; minor isomer was not identified. IR (neat, cm ) 3700-
120 (br m), 3065(w), 3033 (w), 2926 (m), 1715 (w), 1609 (s), 1593 (s), 1514 (m), 1429 (m), 1327 (w),
+
266 (m), 1217 (m), 1105 (s), 1028 (m), 911 (w), 810 (w); FAB-MS (m/z) 1745 (2.0), 1744 ([M+Na] ,
+
.0), 1724 (68), 1723 (100), 1722 ([M+H] , 98), 1190 (17), 685 (31), 664 (18), 663 (100), 662 (48), 648
+
(
88); FAB-HRMS calcd for C H O [M+H] , 1721.6777; found: 1721.6731.
1
14 97 16

186
HETEROCYCLES, Vol. 67, No. 1, 2006
Procyanidin B3 3’’-O-gallate (5). A solution of 26 (80.0 mg, 0.046 mmol) in 22 mL of THF/
CH OH/H O (20/1/1) was hydrogenated over 20% Pd(OH) /C (5 mg) for 12 h at rt. Filtration and
3
2
2
concentration afforded a pale brown solid, which was purified by Sephadex® LH-20 column
chromatography (CH OH) and then HPLC purification to give 24.8 mg (74%) of pure 5 as a pale brown
3
2
5
1
amorphous solid. [α] = -127.3° (c 0.11, CH OH); H-NMR (400 MHz, 10% D O in CD COCD , 0.57 :
D
3
2
3
3
0
.43 mixture of rotational isomers) major isomer: 6.98 (1.14H, s), 6.81-6.77 (0.57H, m), 6.69 (0.57H, d, J
1.7 Hz), 6.61 (0.57H, d, J = 8.3 Hz), 6.60 (0.57H, d, J = 8.3 Hz), 6.48 (0.57H, dd, J = 1.7, 8.3 Hz), 6.15
0.57H, s, 6''), 6.14 (0.57H, d, J = 1.7, 8.3 Hz), 5.94 (0.57H, d, J = 2.2 Hz, 8), 5.76 (0.57H, d, J = 2.2 Hz,
), 5.21 (0.57H, ddd, J = 5.6, 6.4, 6.4 Hz, 3''), 5.05 (0.57H, d, J = 6.4 Hz, 2''), 4.52 (0.57H, dd, J = 7.8, 9.5
Hz, 3), 4.46 (0.57H, d, J = 7.8 Hz, 4), 4.29 (0.57H, d, J = 9.5 Hz, 2), 2.73 (0.57H, dd, J = 5.6, 16.6 Hz,
=
(
6
4
6
8
''), 2.66 (0.57H, dd, J = 6.4, 16.6 Hz, 4''); minor isomer: 7.08 (0.86H, s), 7.07 (0.43H, d, J = 1.7 Hz),
.95 (0.43H, d, J = 1.7 Hz), 6.91 (0.43H, dd, J = 1.7, 8.3 Hz), 6.81-6.77 (0.86H, m), 6.71 (0.43H, d, J =
.3 Hz), 6.05 (0.43H, s, 6''), 5.87 (0.43H, d, J = 2.2 Hz, 8), 5.83 (0.43H, d, J = 2.2 Hz, 6), 5.34 (0.43H,
ddd, J = 5.4, 5.6, 6.6 Hz, 3''), 5.17 (0.43H, d, J = 6.6 Hz, 2''), 4.60 (0.43H, d, J = 8.0 Hz, 4), 4.54 (0.43H,
dd, J = 8.0, 9.3 Hz, 3), 4.37 (0.43H, d, J = 9.3 Hz, 2), 2.88 (0.43H, dd, J = 5.4, 16.6 Hz, 4''), 2.73 (0.43H,
1
3
dd, J = 5.6, 16.6 Hz, 4''); C-NMR (100 MHz, 10% D O in CD COCD , 0.57 : 0.43 mixture of rotational
2
3
3
isomers) 166.4, 166.3, 158.4, 157.0, 156.9, 156.8, 156.7, 156.5, 155.6, 155.2 (x2), 155.0, 154.0, 153.7,
1
1
1
45.8, 145.7, 145.5, 145.3, 145.1, 145.0, 144.9, 144.1, 131.8 (x2), 130.6, 130.2, 121.0 (x2), 120.4, 119.7,
19.2, 118.7, 116.4 (x2), 115.9, 115.7 (x4), 115.5, 114.1, 113.8, 109.9, 109.8, 107.9, 107.3, 106.2, 105.9,
00.4 (x2), 98.8 (x2), 97.3, 96.8, 96.3 (x2), 95.9 (x2), 83.5 (2), 83.4 (2), 79.2 (2''), 78.2 (2''), 73.4 (3), 72.6
+
(
3), 70.6 (3''), 70.3 (3''), 37.8 (x2) (4), 24.9 (4''), 24.5 (4''); FAB-MS (m/z) 754 (41), 753 ([M+Na] , 100),
+
+
7
52 (57), 732 (33), 731 ([M+H] , 66), 730 (45); FAB-HRMS calcd for C H O [M+H] , 731.1612;
37 31 16
found: 731.1543.
1
1
Procyanidin B4 3’’-O-gallate (9). A solution of 27 (130 mg, 0.075 mmol) in 44 mL of THF/
CH OH/H O (20/1/1) was hydrogenated over 20% Pd(OH) /C (10 mg) for 8 h at rt. Filtration and
3
2
2
concentration afforded a pale brown solid, which was purified by Sephadex® LH-20 column
chromatography (CH OH) and then HPLC purification to give 35.1 mg (53%) of pure 9 as a pale brown
3
2
3
25
11
22
amorphous solid. [α] = -309.2° (c 0.095, CH OH), [α] = -279.1° (c 0.095, acetone), {lit., [α] =
D
3
D
D
1
-
255.7° (c 0.56, acetone); H-NMR (400 MHz, 10% D O in CD COCD , 0.56 : 0.44 mixture of rotational
2 3 3
isomers) major isomer: 7.23 (0.56H, d, J = 1.7 Hz), 6.92 (1.12H, s), 7.00-6.70 (1.68H, m), 6.65 (0.56H, d,
J = 8.3 Hz), 6.50 (0.56H, dd, J = 1.7, 8.3 Hz), 6.15 (0.56H, br s), 6.02 (0.56H, br s), 5.83-5.82 (0.56H, br
s), 5.43-5.45 (0.56H, m, 3''), 5.18 (0.56H, br s, 2''), 4.73 (0.56H, d, J = 8.0 Hz, 2), 4.62 (0.56H, dd, J = 8.0,

HETEROCYCLES, Vol. 67, No. 1, 2006
187
9
.8 Hz, 3), 4.47 (0.56H, d, J = 9.8 Hz, 4), 3.04-2.93 (0.56H, m, 4''), 2.81 (0.56H, d, J = 1.7 Hz, 4''); minor
isomer: 7.02 (0.88H, s), 7.00-6.70 (1.76H, m), 6.61 (0.44H, d, J = 8.3 Hz), 6.28 (0.44H, dd, J = 1.7, 8.3
Hz), 6.18 (0.44H, d, J = 2.2 Hz), 5.96 (0.44H, d, J = 2.2 Hz), 5.83 (0.44H, s), 5.32-5.31 (0.44H, m, 3''),
5
8
.12 (0.44H, br s, 2''), 4.54 (0.44H, d, J = 8.8 Hz, 2), 4.40 (0.44H, d, J = 9.7 Hz, 4), 4.24 (0.44H, dd, J =
1
3
.8, 9.7 Hz, 3), 3.07-2.93 (0.88H, m, 4''); C-NMR (100 MHz, 10% D O in CD COCD , 0.56 : 0.44
2
3
3
mixture of rotational isomers) major isomer: 166.5, 166.4, 158.1, 157.9, 157.2, 157.0, 156.8, 156.3,
1
1
1
9
3
3
55.68, 155.67, 155.5, 155.3, 155.0, 154.8, 145.7, 145.6, 145.5 (x2), 145.4 (x2), 145.2, 144.8, 131.9,
31.8, 131.0, 130.5, 121.4, 121.1, 120.6, 120.0, 119.8, 118.8, 116.1, 115.9, 115.7, 115.6, 115.5, 115.4,
14.9 (x2), 114.1 (x2), 110.2, 109.8, 107.5, 106.7, 106.4, 105.9, 99.7 (x2), 98.3 (x2), 97.3, 97.1, 97.0,
6.8, 96.2, 95.9, 83.4 (2), 83.2 (2), 78.4 (2''), 77.9 (2''), 73.0 (3), 72.9 (3), 69.62 (3''), 69.59 (3''), 38.1 (4),
+
7.8 (4), 26.8 (4''), 26.7 (4''); FAB-MS (m/z) 733 (7.0), 732 (18), 731 ([M+H] , 25), 720 (56), 636 (44),
+
71 (82), 306 (100); FAB-HRMS calcd for C H O [M+H] , 731.1612; found: 731.1637.
3
7
31 16
Measurement of DPPH radical scavenging activity: All of the assay samples were HPLC pure. DPPH
radical scavenging activity was measured with the general DPPH method described in the previous
1
paper.
DNA polymerase assays: All of the assay samples were HPLC pure. Inhibitory activity against calf
DNA polymerase a (0.05 units) and rat DNA polymerase β (0.05 units) was measured with the general
1
method described in the previous paper. One unit of DNA polymerase activity was defined as the amount
of enzyme that catalyzed the incorporation of 1 nmol of deoxyribonucleotide triphosphates (i.e., dTTP)
into synthetic template-primers (i.e. poly(dA)/oligo(dT)12-18, A/T = 2/1) in 60 min at 37 °C under normal
reaction conditions for each enzyme.
ACKNOWLEDGEMENTS
Partial financial support of this research under the NOVARTIS Foundation (Japan) for the Promotion of
Science is gratefully acknowledged. We also thank the Japan Society for the Promotion of Science (JSPS)
for the Young Science Research Fellowship (to A. S.).
REFERENCES AND NOTES
1
.
This report is Part 11 in the series “Synthetic studies of proanthocyanidins”. See also part 10 and part
. (a) Part 10: A. Saito, Y. Mizushina, H. Ikawa, H. Yoshida, Y. Doi, A. Tanaka, and N. Nakajima,
Bioorganic Med. Chem., 2005, 13, 2759. (b) Part 9: A. Saito, M. Emoto, A. Tanaka, Y. Doi, K. Shoji,
9

188
HETEROCYCLES, Vol. 67, No. 1, 2006
Y. Mizushina, H. Ikawa, H. Yoshida, N. Matsuura, and N. Nakajima, Tetrahedron, 2004, 60, 12043.
J. B. Harborne, The Flavonoids: Advances in research from 1986. Chapman and Hall, London, 1993.
J. B. Harborne and H. Baxter, The Handbook of Natural Flavonoids, John Wiley & Sons, New York,
2
3
.
.
1
999.
4
5
6
.
.
.
C. S. Yang, P. Maliakai, and X. Meng, Annu. Rev. Pharmacol. Toxicol., 2002, 42, 25.
H. Tachibana, K. Koga, Y. Fujimura, and K. Yamada, Nature Structural Mol. Biol., 2004, 11, 380.
T. Hatano, H. Miyatake, M. Natsume, N. Osakabe, T. Takizawa, H. Ito, and T. Yoshida,
Phytochemistry, 2002, 59, 749.
7
8
.
.
For many papers about isolation and bioactivities of galloyl-substituted procyanidin series, see ref. 1.
(a) A. Saito, N. Nakajima, A. Tanaka, and M. Ubukata, Biosci. Biotechnol. Biochem., 2002, 66, 1764.
(
b) A. Saito, N. Nakajima, A. Tanaka, and M. Ubukata, Tetrahedron, 2002, 58, 7829. (c) A. Saito, N.
Nakajima, N. Matsuura, A. Tanaka, and M. Ubukata, Heterocycles, 2004, 62, 479. (d) A. Saito, A.
Tanaka, M. Ubukata, and N. Nakajima, Synlett, 2004, 1069. (e) A. Saito, Y. Doi, A. Tanaka, N.
Matsuura, M. Ubukata, and N. Nakajima, Bioorg. Med. Chem., 2004, 12, 4783.
9
.
(a) A. Saito, N. Nakajima, A. Tanaka, and M. Ubukata, Tetrahedron Lett., 2003, 44, 5449. (b) A.
Saito, N. Nakajima, A. Tanaka, and M. Ubukata, Heterocycles, 2003, 61, 287. (c) A. Saito, A.
Tanaka, M. Ubukata, and N. Nakajima, Synlett, 2004, 2040.
1
1
1
1
1
0. T. Hatano and R. W. Hemingway, J. Chem. Soc., Perkin Trans. 2, 1997, 1035.
1. 23% of the starting material, 14% of 4 and 14% of 6 were obtained. See experimental section.
2. G. Nonaka, O. Kawahara, and I. Nishioka, Chem. Pharm. Bull., 1983, 31, 3906.
3. I. Oguni, K. Nasu, S. Kanaya, Y. Ota, S. Yamamoto, and T. Nomura, Jpn. J. Nutr., 1989, 47, 93.
4. We reported the IC value of compound (6) against calf DNA polymerase α to be 8.1 µM in previous
5
0
1
b
paper. But reevaluation of the inhibitory activity of 6 revealed the IC values for calf DNA
5
0
polymerase α and rat DNA polymerase β to be 0.12 and 125 µM, respectively.
1
5. A. Kornberg and T. Baker, DNA Replication, W. H. Freeman & Co, New York, 1992, Chapter 6,
p.197.