BIOSCIENCE, BIOTECHNOLOGY, AND BIOCHEMISTRY
5
chromatography (30 g). Elution with dichlorometh-
ane-ethyl acetate (2:1) furnished 8b as a yellow amor-
phous solid (1.30 g, 89%). 1H-NMR (500 MHz, CDCl3)
: 1.21 (3H, d, J = 6.3 Hz), 1.98 (3H, s), 2.03 (3H, s),
2.04 (3H, s), 2.07 (3H, s), 2.12 (3H, s), 2.13 (6H, s), 2.15
(3H, s), 3.89 (1H, ddd, J = 2.2, 5.6, 9.8 Hz), 3.99 (1H,
dd, J = 7.5, 9.3 Hz), 4.08 (1H, dq, J = 6.3, 9.7 Hz), 4.14
(1H, dd, J = 2.2, 12.2 Hz), 4.26 (1H, dd, J = 5.6, 12.2 Hz),
5.02-5.09 (4H, m), 5.13 (1H, d, J = 7.5 Hz) 5.21 (1H, dd,
J = 3.2, 10.0 Hz), 5.34 (1H, dd, J = 9.3, 9.3 Hz), 6.77 (2H,
s) 6.78 (1H, d, J = 16.2 Hz), 6.82 (2H, d, J = 8.6 Hz), 7.36
(1H, d, J = 16.2 Hz), 7.41 (2H, d, J = 8.6 Hz). 13C-NMR
(125 MHz, CDCl3) : 17.4, 20.6, 20.6, 20.6, 20.7, 20.7,
20.8, 20.9, 62.0, 67.0, 68.3, 68.5, 70.0, 70.8, 72.1, 74.1,
76.8, 98.2, 98.7, 109.4, 116.2, 121.7, 123.9, 126.2, 130.7,
147.0, 149.4, 157.5, 159.4, 168.5, 169.8, 169.9, 170.2,
170.3, 170.4, 170.8, 190.5. IR max cm−1: 3360, 2941, 1741,
1601, 1366, 1214, 1169, 1036. HR-MS [ESI+, (M + Na)+]:
calculated for C43H48NaO22, 939.2535; found, 939.2515.
[]D21 –30.1° (c 1.0, chloroform).
2′,6′-Diacetoxy-4′-[hexa-O-acetyl-(2-O--L-
rhamnopyranosyl--D-glucopyranosyl)oxy]
dihydrochalcone (4b)
To a solution of 8c (193 mg, 0.184 mmol) in THF
(20 mL) were added palladium hydroxide (20% on
carbon, 48.2 mg, 68.6 mol) and triethylamine (64 L,
0.459 mmol) and the mixture was stirred under hydro-
gen atmosphere for 3.5 h at room temperature. e mix-
ture was filtered to remove insoluble materials with a
pad of Celite. e precipitates were washed with THF
and the combined filtrate and washings were concen-
trated in vacuo. e residue was purified by silica gel
column chromatography (11 g). Elution with dichlo-
romethane-ethyl acetate (3:1) furnished 4b as a colorless
1
amorphous solid (140 mg, 84%). H-NMR (500 MHz,
CDCl3) : 1.18 (3H, d, J = 6.1 Hz), 1.96 (3H, s), 2.01
(3H, s), 2.02 (3H, s), 2.04 (3H, s), 2.09 (3H, s), 2.12 (6H,
s), 2.13 (3H, s), 2.95-2.98 (2H, m), 3.04-3.07 (2H, m),
3.86 (1H, ddd, J = 2.2, 5.6, 9.8 Hz), 3.95 (1H, dd, J = 7.5,
9.3 Hz), 4.02 (1H, dq, J = 6.1, 9.8 Hz), 4.11 (1H, dd,
J = 2.2, 12.5 Hz), 4.23 (1H, dd, J = 5.6, 12.5 Hz), 4.99-5.06
(4H, m), 5.09 (1H, d, J = 7.5 Hz) 5.17 (1H, dd, J = 3.4,
10.0 Hz), 5.31 (1H, dd, J = 9.3, 9.3 Hz), 6.71 (2H, s), 7.17-
7.20 (3H, m), 7.26-7.29 (2H, m). 13C-NMR (125 MHz,
CDCl3) : 17.4, 20.6, 20.6, 20.6, 20.7, 20.7, 20.8, 20.9,
29.5, 45.4, 61.9, 67.0, 68.3, 68.4, 70.0, 70.8, 72.1, 74.0,
76.7, 98.2, 98.6, 109.0, 122.4, 126.2, 128.5, 128.5, 140.9,
148.9, 157.5, 168.1, 169.6, 169.7, 170.0, 170.1, 170.2,
170.5, 199.3. IR max cm−1: 2939, 1741, 1616, 1366, 1218,
1176, 1037. HR-MS [ESI+, (M + Na)+]: calculated for
C43H50NaO21, 925.2742; found, 925.2752. []D22 –28.9°
(c 1.0, chloroform).
2′,6′-Diacetoxy-4′-[hexa-O-acetyl-(2-O--L-
rhamnopyranosyl--D-glucopyranosyl)oxy]-4″-trif
luoromethylsufonyloxychalcone (8c)
To a solution of 8b (304 mg, 0.332 mmol) in dichlo-
romethane (2.5 mL) were added 2,6-lutidine (115 L,
0.993 mmol) and trifluoromethanesulfonic anhydride
(170 L, 1.01 mmol) at 0 °C under argon atmosphere,
and the mixture was stirred for 1 h at room tempera-
ture. e mixture was poured into water and the organic
materials were extracted with dichloromethane twice.
e combined extracts were washed with hydrochlo-
ric acid (1 M) and brine, dried over anhydrous sodium
sulfate and concentrated in vacuo. e residue was puri-
fied by silica gel column chromatography (12 g). Elution
with dichloromethane-ethyl acetate (3:1) furnished 8c
2′,6′-Dihydroxy-4′-(2-O--L-rhamnopyranosyl--
D-glucopyranosyl)oxydihydrochalcone (4a)
To a solution of 4b (137 mg, 0.152 mmol) in acetoni-
trile (7 mL) was added an aqueous solution of sodium
hydroxide (0.25 M, 7 mL) and the mixture was stirred
for 1 h at room temperature. e reaction was quenched
with DOWEX 50 W-X8 (H+ form) and the mixture was
filtered to remove insoluble materials. e filtrate was
concentrated in vacuo. e residue was purified by pre-
parative TLC developed with acetonitrile-water (5:8)
furnished 4a as a colorless amorphous solid (47.4 mg,
1
as a yellow amorphous solid (208 mg, 60%). H-NMR
(500 MHz, CDCl3) : 1.22 (3H, d, J = 6.3 Hz), 1.99 (3H,
s), 2.03 (3H, s), 2.04 (3H, s), 2.07 (3H, s), 2.12 (3H, s),
2.14 (6H, s), 2.15 (3H, s), 3.90 (1H, ddd, J = 2.2, 5.6,
9.8 Hz), 3.99 (1H, dd, J = 7.6, 9.3 Hz), 4.07 (1H, dq,
J = 6.3, 9.7 Hz), 4.15 (1H, dd, J = 2.2, 12.5 Hz), 4.27 (1H,
dd, J = 5.6, 12.5 Hz), 5.03-5.09 (4H, m), 5.14 (1H, d,
J = 7.5 Hz) 5.21 (1H, dd, J = 3.4, 10.0 Hz), 5.34 (1H, dd,
J = 9.3, 9.3 Hz), 6.78 (2H, s), 6.90 (1H, d, J = 16.2 Hz),
7.31 (2H, d, J = 8.8 Hz), 7.40 (1H, d, J = 16.2 Hz), 7.61
(2H, d, J = 8.8 Hz). 13C-NMR (125 MHz, CDCl3) : 17.4,
20.5, 20.5, 20.6, 20.6, 20.7, 20.8, 20.9, 61.9, 67.0, 68.2,
68.3, 70.0, 70.8, 72.2, 74.0, 76.7, 98.2, 98.6, 109.3, 118.6
(q, J = 321 Hz), 121.2, 122.1, 128.3, 130.1, 134.5, 143.4,
149.5, 150.6, 157.9, 168.3, 169.6, 169.3, 170.0, 170.1,
170.2, 170.5, 189.8. IR max cm−1: 2942, 1742, 1616, 1424,
1367, 1208, 1038. HR-MS [ESI+, (M + Na)+]: calculated
1
55%). H-NMR (500 MHz, DMSO-d6) : 1.15 (3H, d,
J = 6.1 Hz), 2.86-2.89 (2H, m), 3.14-3.21 (2H, m), 3.28-
3.34 (3H, m), 3.41-3.48 (4H, m), 3.62-3.68 (3H, m), 4.46
(1H, d, J = 5.6 Hz), 4.54 (1H, dd, J = 5.1, 5.1 Hz), 4.63
(1H, d, J = 4.4 Hz), 4.66 (1H, d, J = 4.7 Hz), 5.04 (1H,
d, J = 7.5 Hz), 5.06 (1H, br), 5.09 (1H, d, J = 5.6 Hz),
5.28 (1H, d, J = 5.3 Hz), 6.99 (2H, s), 7.14-7.17 (1H, m),
7.22-7.28 (4H, m), 12.28 (2H, br). 13C-NMR (125 MHz,
DMSO-d6) :18.6, 30.5, 45.7, 60.7, 68.8, 69.9, 70.8, 71.0,
72.3, 77.0, 77.3, 77.6, 95.2, 97.5, 101.1, 105.7, 126.3, 128.7,
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for C44H47F3NaO24S, 1071.2028; found, 1071.2056. []D
–26.3° (c 1.0, chloroform).