Total Synthesis of (±)-Puyanin and (±)-4'-O-Methylbonannione
J=11.2 Hz, 1H, =CH), 5.25 (t, J=13.2 Hz, 1H,
bient temperature, H
ture was extracted with Et
bined organic layers were washed with H O and brine,
2
dried over anhydrous Na SO , and evaporated under
2
O (5 mL) was added and the mix-
=
CH), 5.90 (s, 1H, ArH), 7.09 (s, 1H, OH), 9.55 (s, 1H,
2
O (10 mL×3). The com-
OH), 11.67 (s, 1H, OH); IR (KBr) vmax: 3313, 2925,
-
1
1
629, 1604, 1436, 1365, 1288, 1149, 1070 cm ; EIMS
2 4
+
m/z (%): 304 ([M ], 38), 289 (3), 261 (9), 235 (25), 219
reduced pressure. The residue was purified by silica gel
column chromatography eluting with petroleum ether-
EtOAc (V∶V=2∶1) to give flavanone 7 (122.4 mg,
(
22), 181 (100).
,6-Bis[(methoxy)methoxy]-2-hydroxy-3-(1'-geran-
yl)acetophenone (5) To a stirred mixture of 4 (608
mg, 2 mmol) and anhydrous K CO (1.932 g, 14 mmol)
in dry acetone (40 mL) was added dropwise MOMCl
400 mg, 5 mmol). The mixture was heated at reflux for
.5 h, then cooled to room temperature, filtered, and
4
1
80% yield) as a light yellow oil. H NMR (400 MHz) δ:
2
3
1.57, 1.64, 1.65 (s, 9H, 3CH
3
), 1.85—2.04 (m, 4H,
4''-2H and 5''-2H), 2.79 (dd, J=3.0, 16.6 Hz, 1H, H3β),
(
1
2.99 (dd, J=13.0, 16.6 Hz, 1H, H3α), 3.31 (d, J=7.2 Hz,
2H, 1''-2H), 3.49, 3.54, 3.83 (s, 9H, 3OCH
3
), 5.06—
evaporated under reduced pressure. The resulting resi-
due was purified by silica gel column chromatography
eluting with petroleum ether-EtOAc (V∶V=6∶1) to
5.10 (m, 1H, J=7.2 Hz, =CH), 5.17 (t, J=7.0 Hz, 1H,
=CH), 5.24, 5.26 (s, 4H, 2OCH
2
O), 5.35 (dd, J=2.8,
12.8 Hz, 1H, 2-H), 6.57 (s, 1H, 6-H), 6.93 (d, J=8.8 Hz,
2H, 3'-H, 5'-H), 7.38 (d, J=8.4 Hz, 2H, 2'-H, 6'-H); IR
(KBr) vmax: 2960, 2910, 1681, 1595, 1515, 1444, 1334,
afford 5 (564 mg, 72% yield) as a light yellow liquid.
1
3
H NMR (CDCl , 400 MHz) δ: 1.56, 1.64, 1.77 (s, 9H,
-
1
3
CH
3
), 1.92—2.05 (m, 4H, 4'-2H and 5'-2H), 2.65 (s,
1253, 1151, 1068, 1037 cm ; EI-MS m/z (%): 510
+
3H, COCH
3
), 3.31 (d, J=7.2 Hz, 2H, 1'-2H), 3.48, 3.51
([M ], 3), 465 (5), 387 (17), 355 (18), 343 (23), 331
(s, 6H, 2OCH
3
), 5.06—5.25 (m, 4H, 2OCH
2
O, 2'-H and
(12), 209 (8), 161 (41), 134 (24), 45 (100).
6
'-H), 6.38 (s, 1H, ArH), 13.82 (s, 1H, OH); IR (KBr)
(±)-Puyanin(5,7-dihydroxy-4'-methoxy-8-(1''-ger-
anyl)flavanone (1) To a stirred solution of 7 (51 mg,
0.1 mmol) in MeOH (2 mL) was added dropwise 3
mol/L HCl (0.4 mL). The solution was heated at reflux
v
1
3
max: 2973, 2921, 1614, 1485, 1423, 1407, 1373, 1272,
232, 1155, 1107, 1043, 962 cm ; EI-MS m/z (%):
92 ([M ], 4), 347 (10), 273 (7), 269 (3), 225 (3), 69
-
1
+
(
10), 45 (100).
',6'-Bis[(methoxy)methoxy]-2'-hydroxy-4-meth-
oxy-3'-(1''-geranyl)chalcone (6) To a stirred mixture
for 45 min, then H
tion was extracted with EtOAc. The combined organic
layers were washed with H O and brine, dried over an-
hydrous Na SO , and evaporated under reduced pres-
2
O (5 mL) was added, and the solu-
4
2
of KOH (2.8 g, 50 mmol) in H
2
O-EtOH (6.7 mL, V∶
2
4
V=2∶3) cooled to 0 ℃ in an ice bath was added
dropwise a solution of 5 (392 mg, 1 mmol) and
p-methoxybenzaldehyde (149.6 mg, 1.1 mmol, prepared
from p-hydroxybenzaldehyde) in EtOH (2 mL) cooled
to 0 ℃ under nitrogen. The reaction mixture was kept in
ice bath for 1 h, then at ambient temperature for 24 h.
The resulting mixture was poured into ice water (5 mL),
and the solution was adjusted to pH 3—4 with 3 mol/L
sure. The residue was purified by silica gel column
chromatography eluting with petoleum ether-EtOAc
(V∶V=8∶1) to give 1 (33.7 mg, 80% yield) as a yel-
1
low amorphous solid. m.p. 158—162 ℃; H NMR
3 3
(CDCl , 400 MHz) δ: 1.59, 1.66, 1.71 (s, 9H, 3CH ),
2.01—2.09 (m, 4H, CH
2
), 2.80 (dd, J=3.0, 17.0 Hz, 1H,
H
3β), 3.06 (dd, J=13.0, 17.2 Hz, 1H, H3α), 3.32 (d, J=
7.2 Hz, 2H, 1''-2H), 3.84 (s, 3H, OCH
3
), 5.00—5.06 (m,
HCl, then extracted with CH
2
Cl
2
(5 mL×3). The com-
1H, =CH), 5.21 (t, J=6.8 Hz, 1H, =CH), 5.36 (dd,
J=3.2, 13.0 Hz, 1H, 2-CH), 6.02 (s, 1H, 6-H), 6.25 (s,
1H, 7-OH), 6.95 (d, J=8.8 Hz, 2H, 3'-H, 5'-H), 7.38 (d,
2
bined organic layers were washed with H O and satu-
2 4
rated brine, dried over anhydrous Na SO , and evapo-
rated under reduced pressure. The residue was purified
by silica gel column chromatography eluting with pe-
1
3
J=8.4 Hz, 2H, 2'-H, 6'-H), 12.02 (s, 1H, 5-OH);
C
3
NMR (CDCl , 80 MHz) δ: 195.5 (C-4), 162.9 (C-7),
troleum ether-EtOAc (V∶V=6∶1) to give chalcone 6
161.1 (C-5), 158.8 (C-4'), 137.7 (C-3''), 130.9 (C-1'),
126.6 (C-2'), 126.5 (C-6'), 122.7 (C-6''), 120.4 (C-2''),
113.0 (C-3',5'), 105.1 (C-8), 102.1 (C-10), 95.8 (C-6),
77.7 (C-2), 59.5 (OMe), 42.2 (C-3), 38. (C-4''), 26.0
(C-5''), 25.5 (C-8''), 21.1 (C-1''), 16.6 (C-9''), 15.1
(C-10''); IR (KBr) vmax: 3232, 2929, 1635, 1585, 1515,
1
(392 mg, 75% yield) as a deep yellow liquid. H NMR
(
400 MHz) δ: 1.56, 1.64, 1.78 (s, 9H, 3CH
3
), 1.94—
2
1
4
.06 (m, 4H, 4''-2H and 5''-2H), 3.34 (d, J=7.2 Hz, 2H,
''-2H), 3.35, 3.48, 3.84 (s, 9H, 3OCH
H, 2OCH O, 2''-H and 6''-H), 6.38 (s, 1H, 5'-H), 6.92
2
3
), 5.06—5.26 (m,
-
1
(
2
d, J=6.8 Hz, 2H, 3-H, 5-H), 7.53—7.56 (d, J=6.8 Hz,
1436, 1375, 1296, 1253, 1174, 1074, 1031 cm ; EI-MS
+
H, 2-H, 6-H), 7.83 (s, 2H, H
α
, H
β
), 13.86 (s, 1H, OH);
m/z (%): 422 ([M ], 12), 299 (100), 219 (33), 205 (13),
IR (KBr) vmax: 2918, 2854, 1604, 1577, 1512, 1423,
177 (6), 165 (77), 134 (16), 91 (11), 69 (14), 55 (5).
2',4',6'-Trihydroxy-4-methoxy-3'-(1''-geranyl)chal-
cone (8) To a stirred solution of 6 (255 mg, 0.5 mmol)
in MeOH (10 mL) was added dropwise 3 mol/L HCl (2
mL). The solution was heated at reflux for 15 min, then
-
1
1
316, 1288, 1230, 1172, 1066, 960 cm ; EI-MS m/z
+
(%): 510 ([M ], 3), 465 (5), 422(6), 355 (9), 299 (37),
2
19 (18), 165 (31), 149 (16), 121 (17), 91 (100).
,7-Bis[(methoxy)methoxy]-4'-methoxy-8-(1''-gera-
5
nyl)flavanone (7) To a solution of 6 (153 mg, 0.3
mmol) in EtOH (3.5 mL) were added NaOAc (353 mg,
H
2
O (10 mL) was added, and the solution was extracted
with EtOAc. The combined organic layers were washed
with H O and brine, dried over anhydrous Na SO , and
evaporated under reduced pressure. The residue was
4.3 mmol) and H
2
O (one drop). The mixture was heated
2
2
4
at reflux for 24 h. After the mixture was cooled to am-
Chin. J. Chem. 2011, 29, 521— 524
© 2011 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
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