A. Saito et al. / Tetrahedron 60 (2004) 12043–12049
12047
(5.8), 330 (20), 275 (20), 274 (69), 273 (100), 272 (31);
FAB-HRMS calcd for C22H19O10 [MCH]C, 443.0978;
found:443.0972.
144 mg (0.067 mmol, 71%) of 13 as a white powder;
[a]2D2ZK43.9 (c 0.42, CHCl3); 1H NMR (400 MHz,
CDCl3, 0.66: 0.34 mixture of rotational isomers) major
isomer: 7.40–6.62 (50.82H, m), 6.76 (0.66H, d, JZ1.7 Hz),
6.54 (0.66H, d, JZ8.3 Hz), 6.44 (0.66H, dd, JZ1.7,
8.3 Hz), 6.23 (0.66H, d, JZ2.2 Hz), 6.06 (0.66H, d, JZ
2.2 Hz), 5.96 (0.66H, s), 6.12–5.97 (0.66H, m), 5.38 (0.66H,
ddd, JZ5.6, 7.1, 7.3 Hz), 5.15 (0.66H, d, JZ7.3 Hz), 5.13–
4.53 (18.48H, m), 4.44 (0.66H, d, JZ11.5 Hz), 4.38 (0.66H,
d, JZ11.5 Hz), 3.13 (0.66H, dd, JZ5.6, 16.8 Hz), 2.90
(0.66H, dd, JZ7.1, 16.8 Hz); minor isomer: 7.40–6.53
(26.86H, m), 6.50 (0.34H, dd, JZ1.7, 8.3 Hz), 6.29 (0.34H,
s), 6.18 (0.34H, d, JZ2.2 Hz), 6.14 (0.34H, d, JZ2.2 Hz),
6.12–5.97 (0.34H, m), 5.13–4.53 (10.54H, m), 3.63 (0.34H,
d, JZ9.3 Hz), 3.15–3.11 (0.34H, m), 2.48 (0.34H, dd, JZ
10.0, 17.1 Hz); 13C NMR (100 MHz, CDCl3) major isomer:
165.3, 164.3, 158.3, 157.5, 157.1, 156.6, 155.5, 152.5 (!2),
152.1 (!2), 148.93, 148.88, 148.6, 142.6, 142.1, 137.5–
136.5 (C!19), 131.3, 131.1, 128.6–126.7 (C!27), 125.2,
125.1, 120.4, 120.3, 114.83, 114.75, 114.2, 113.8, 113.7,
111.2, 109.1, 108.7, 108.2, 101.9, 94.8, 94.6, 90.9, 79.7,
78.2, 77.2, 75.13, 75.01, 71.6–69.8 (C!12), 35.2, 24.9;
minor isomer: 165.1, 164.6, 158.1, 157.6, 156.9, 155.9,
153.8, 152.6, 152.5, 152.42, 152.36, 149.1, 148.8, 147.8,
142.5, 142.4, 137.6–136.5 (C!19), 131.1, 131.0, 128.6–
126.7 (C!27), 125.5, 125.0, 120.9, 119.7, 115.9, 114.8,
114.1, 113.8, 113.7, 111.5, 109.2, 109.1, 108.7, 101.7, 94.9,
94.3, 91.3, 80.0, 78.3, 77.6, 75.1, 75.0, 71.6–69.8 (C!12),
35.1, 26.6; IR (neat, cmK1) 3090 (m), 3032 (m), 2930 (m),
2870 (m), 1954 (w), 1811 (w), 1717 (s), 1592 (s), 1514 (s),
1454 (s), 1430 (s), 1375 (s), 1215 (s), 1113 (s), 1028 (s), 910
(w), 856 (w), 810 (w), 754 (s); FAB-MS (m/z) 2145 (0.1),
2144 ([MCH]C, 0.1).
4.1.4. [4,8]-2,3-trans-3,4-trans:2,3-trans-Octa-O-benzyl-
bi-(C)-catechin-3-O-(tri-O-benzyl)gallate (12). To a
solution of 7 (117 mg, 0.18 mmol) and 10 (52 mg,
0.045 mmol) in CH2Cl2 (30 ml) was added dropwise
TMSOTf (0.09 ml, 0.045 mmol, 0.5 M solution in
CH2Cl2) at K20 8C. After stirring for 5 min, the pale
yellow reaction mixture was quenched with sat. sodium
hydrogen carbonate. The aq. solution was extracted with
CHCl3 and the organic phase was washed with water and
brine, and dried (Na2SO4). Filtration, concentration and
preparative silica gel TLC purification (hexane/EtOAc/
CHCl3, 6/1/5) afforded 55 mg (0.032 mmol, 71%) of 12 as a
1
colorless oil; [a]D25ZK155.6 (c 0.44, CHCl3); H NMR
(400 MHz, CDCl3, 0.6: 0.4 mixture of rotational isomers)
major isomer: 7.45–6.65 (37.2H, m), 6.46 (0.6H, dd, JZ1.7,
8.3 Hz), 6.24 (0.6H, d, JZ2.2 Hz), 6.12 (0.6H, d, JZ
2.2 Hz), 8.05 (0.6H, t, JZ9.5 Hz), 5.87 (0.6H, s), 5.12–4.66
(13.8H, m), 4.44 (0.6H, d, JZ11.7 Hz), 4.39 (0.6H, d, JZ
11.7 Hz), 3.95–3.85 (0.6H, m), 2.90 (0.6H, dd, JZ5.4,
16.6 Hz), 2.73 (0.6H, dd, JZ7.4, 16.6 Hz), 1.60–1.20 (0.6H,
m, OH); minor isomer: 7.45–6.65 (24.0H, m), 6.59 (0.4H, d,
JZ8.3 Hz), 6.56 (0.4H, d, JZ1.7 Hz), 6.35 (0.4H, dd, JZ
1.7, 8.3 Hz), 6.26 (0.4H, s), 6.19 (0.4H, d, JZ2.2 Hz), 6.14
(0.4H, d, JZ2.2 Hz), 5.95 (0.4H, t, JZ9.8 Hz), 5.12–4.66
(9.2H, m), 4.57 (0.4H, d, JZ11.4 Hz), 3.35–3.28 (0.8H, m),
2.89–2.84 (0.4H, m), 2.35–2.25 (0.4H, m), 1.60–1.20 (0.4H,
m, OH); 13C NMR (100 MHz, CDCl3, 0.6: 0.4 mixture of
rotational isomers) major isomer: 164.4, 158.2, 157.8,
156.8, 156.7, 155.9, 152.6, 152.3, 152.2, 148.9, 148.82,
148.80 (C!2), 148.6, 142.2, 142.1, 137.7–136.5 (C!16),
131.5, 130.9, 128.6–126.7 (C!22), 125.7, 125.2, 120.6,
120.2, 114.9, 114.5, 113.8, 113.7, 109.2, 108.8, 108.8,
102.4, 94.9, 94.5, 91.2, 80.8, 79.7, 75.1, 75.0, 71.4–69.7
(C!7), 68.0, 35.4, 26.8; minor isomer: 164.2, 158.1, 157.7,
156.8, 155.7, 155.6, 153.9, 152.3, 152.2, 149.1, 149.0,
148.9, 148.6, 147.9, 142.4, 141.9, 137.7–136.5 (C!16),
131.1, 131.0, 128.6–126.7 (C!22), 126.0, 124.7, 120.9,
119.4, 115.7, 114.8, 114.4, 113.7, 111.3, 110.4, 108.6,
102.2, 94.9, 94.4, 91.2, 80.4, 79.9, 71.4–69.7 (C!9), 68.1,
35.1, 28.0; IR (neat, cmK1) 3519 (br), 3090 (m), 3065 (m),
3033 (m), 2928 (m), 2870 (m), 1954 (w), 1877 (w), 1813
(w), 1721 (m), 1605 (s), 1514 (s), 1499 (s), 1455 (s), 1428
(s), 1381 (s), 1331 (s), 1264 (s), 1113 (s), 1065 (s), 911 (w),
853 (w), 812 (w), 737 (s), 696 (s); FAB-MS (m/z) 1281
(100), 1746 (11), 1745 (14), 1744 ([MCNa]C, 7), 1724 (7),
1723 (10), 1722 ([MCH]C, 9); FAB-HRMS calcd for
C114H97O26 [MCH]C, 1721.6777; found:1721.6879.
4.1.6. Procyanidin B3-3-O-gallate (2). A solution of 12
(200 mg, 0.12 mmol) in 22 mL of THF/MeOH/H2O, 20/1/1
was hydrogenated over 20% Pd(OH)2/C (5 mg) for 8 h at rt.
Filtration and concentration afforded a pale brown solid,
which was purified by Sephadexw LH-20 column chromato-
graphy (EtOH) and HPLC purification to give 70 mg
(0.096 mmol, 78%) of procyanidin B3-3-O-gallate 2 as a
colorless amorphous solid; [a]2D5ZK180.7 (c 0.28, Me2CO)
{lit.18a [a]D25ZK170.1 (c 0.72, Me2CO)}; 1H NMR
(400 MHz, 10% D2O in CD3COCD3, 0.6: 0.4 mixture of
rotational isomers) major isomer: 6.86 (1.2H, s), 6.79 (0.6H,
d, JZ1.7 Hz), 6.72 (0.6H, d, JZ1.7 Hz), 6.69 (0.6H, d, JZ
8.3 Hz), 6.58 (0.6H, d, JZ8.3 Hz), 6.49 (0.6H, dd, JZ1.7,
8.3 Hz), 6.33 (0.6H, dd, JZ1.7, 8.3 Hz), 6.19 (0.6H, dd, JZ
8.6, 10.0 Hz, C3), 6.02 (0.6H, s, D6), 5.95 (0.6H, d, JZ
2.2 Hz, C8), 5.86 (0.6H, d, JZ2.2 Hz, C6), 4.75 (0.6H, d,
JZ7.7 Hz, F2), 4.72 (0.6H, d, JZ8.6 Hz, C2), 4.62 (0.6H,
d, JZ10.0 Hz, C4), 3.84 (0.6H, ddd, JZ5.6, 7.7, 8.8 Hz,
F3), 2.71 (0.6H, dd, JZ5.6, 16.3 Hz, F4), 2.52 (0.6H, dd,
JZ8.8, 16.3 Hz, F4); minor isomer: 7.00 (0.4H, d, JZ
1.7 Hz), 6.98 (0.8H, s), 6.90–6.62 (1.6H, m), 6.65 (0.4H, d,
JZ8.3 Hz), 6.16 (0.4H, dd, JZ8.8, 10.3 Hz), 6.13 (0.4H, s),
5.87 (0.4H, d, JZ2.2 Hz), 5.86–5.84 (0.4H, m), 4.75–4.73
(0.4H, m), 4.66 (0.4H, d, JZ10.3 Hz), 4.43 (0.4H, d, JZ
8.8 Hz), 3.64–3.59 (0.4H, m), 2.85 (0.4H, dd, JZ5.9,
16.1 Hz), 2.53–2.48 (0.4H, m); 13C NMR (100 MHz, 10%
D2O in CD3COCD3, 0.6: 0.4 mixture of rotational isomers)
major isomer: 165.5, 158.0, 157.6, 156.9, 155.8, 154.8,
154.7, 145.7–145.6 (C!4), 144.91, 144.85, 131.5, 130.6,
4.1.5. [4,8]-2,3-trans-3,4-trans:2,3-trans-Octa-O-benzyl-
bi-(C)-catechin-3,300-di-O-(tri-O-benzyl)gallate (13). To
a solution of 9 (418 mg, 0.39 mmol) and 10 (110 mg,
0.067 mmol) in CH2Cl2 (50 ml) was added dropwise
TMSOTf (0.19 ml, 0.095 mmol, 0.5 M solution in
CH2Cl2) at -20 8C. After stirring for 5 min, the pale yellow
reaction mixture was quenched with sat. sodium hydrogen
carbonate. The aq. solution was extracted with CHCl3 and
the organic phase was washed with water and brine, and
dried (Na2SO4). Filtration, concentration and preparative
silica gel column chromatography (benzene) afforded