Hop Phytoestrogen 8-Prenylnaringenin
Journal of Medicinal Chemistry, 2006, Vol. 49, No. 25 7363
3-Methyl-2,4,6-trihydroxyacetophenone (4a). Yield: 80%. 1H
NMR (300 MHz, DMSO-d6) δ 1.81 (s, 3H), 2.53 (s, 3H), 5.98 (s,
1H), 10.29, 10.52 and 13.95 (3s, 1H each s); 13C NMR (75 MHz,
DMSO-d6) δ 7.98, 33.16, 94.52, 101.92, 104.42, 160.69, 163.32,
164.00, 203.10. HRMS calcd for C9H9O4 [M - H]-, 181.0501;
found, 181.0512.
3-n-Propyl-2,4,6-trihydroxyacetophenone (4b). Yield: 77%.
1H NMR (300 MHz, DMSO-d6) δ 0.83 (br t, 3H, J ) 7.3 Hz),
1.37 (m, 2H), 2.35 (br t, 2H, J ) 7.3 Hz), 2.52 (s, 3H), 5.97 (s,
1H), 10.21, 10.50 and 13.97 (3s, 1H each s); 13C NMR (75 MHz,
DMSO-d6) δ 14.74, 22.47, 24.44, 33.18, 94.56, 104.41, 106.97,
160.78, 163.37, 164.12, 203.15. HRMS calcd for C11H13O4 [M -
H]-, 209.0814; found, 209.0811.
4. General Procedure for the Preparation of 3-Alkyl-2-
hydroxy-4,6-bis(methoxymethoxy)-acetophenones (5a-j). To a
stirring mixture of 3-alkyl-2,4,6-trihydroxyacetophenone (4a-j) and
anhydrous K2CO3 (7 equiv) in dry acetone (3 mL/mmol 4a-j),
MOMCl (2.5 equiv) was added dropwise.40 The reaction mixture
was heated to reflux and allowed to stir for 1 h. After cooling to
room temperature, the reaction mixture was filtered, and the organic
phase was concentrated under reduced pressure. The residue was
purified by column chromatography (hexane/EtOAc) to afford 5a-
j.
129.05, 130.93, 143.03, 158.39, 159.41, 161.24, 163.29, 193.51.
HRMS calcd for C24H29O8 [M - H]-, 445.1862; found, 445.1876.
6. General Procedure for the Preparation of 8-Alkyl-5,7,4′-
tris(methoxymethoxy)flavanones (7a-j). To a stirring solution
of 3′-alkyl-2′-hydroxy-4,4′,6′-tris(methoxymethoxy)chalcone (6a-
j) in EtOH (5 mL/mmol) were added NaOAc (4 equiv) and H2O
(0.4 mL/mmol 6a-j).40 The reaction mixture was heated to reflux
for 20 h and allowed to cool to room temperature. The mixture
was then diluted with H2O and extracted with Et2O. The combined
organic phases were washed with brine, dried over anhydrous
MgSO4, and concentrated under reduced pressure. The residue was
purified by column chromatography (hexane/EtOAc) to afford 7a-
j, while 6a-j was recovered also.
8-Methyl-5,7,4′-tris(methoxymethoxy)flavanone (7a). Yield:
1
53%. H NMR (300 MHz, DMSO-d6) δ 1.96 (s, 3H), 2.66 (dd,
1H, J ) 2.9, 16.4 Hz), 3.03 (dd, 1H, J ) 12.6, 16.4 Hz), 3.36,
3.37 and 3.38 (3s, 3H each s), 5.17, 5.19 and 5.27 (3s, 2H each s),
5.48 (dd, 1H, J ) 2.9, 12.6 Hz), 6.49 (s, 1H), 7.05 (d, 2H, J ) 8.5
Hz), 7.43 (d, 2H, J ) 8.5 Hz); 13C NMR (75 MHz, DMSO-d6) δ
8.77, 45.33, 56.24, 56.70, 78.27, 94.42, 94.61, 95.78, 96.67, 107.75,
108.05, 116.78, 128.42, 133.02, 157.39, 157.56, 160.67, 161.35,
189.46. HRMS calcd for C22H27O8 [M + H]+, 419.1706; found,
419.1691.
3-Methyl-2-hydroxy-4,6-bis(methoxymethoxy)acetophenone
(5a). Yield: 64%. 1H NMR (300 MHz, DMSO-d6) δ 1.93 (s, 3H),
2.61 (s, 3H), 3.37 and 3.42 (2s, 3H each s), 5.28 and 5.29 (2s, 2H
each s), 6.37 (s, 1H), 13.82 (s, 1H); 13C NMR (75 MHz, DMSO-
d6) δ 8.11, 33.66, 56.72, 57.19, 92.37, 94.56, 95.21, 106.75, 106.87,
158.93, 161.41, 163.29, 204.24. HRMS calcd for C13H17O6 [M -
H]-, 269.1025; found, 269.1027.
8-n-Propyl-5,7,4′-tris(methoxymethoxy)flavanone (7b). Yield:
61%. H NMR (300 MHz, DMSO-d6) δ 0.83 (br t, 3H, J ) 7.3
1
Hz), 1.45 (m, 2H), 2.50 (br t, 2H, J ) 7.0 Hz), 2.66 (dd, 1H, J )
2.6, 16.5 Hz), 2.98 (dd, 1H, J ) 12.5, 16.5 Hz), 3.36, 3.37 and
3.39 (3s, 3H each s), 5.17, 5.19 and 5.26 (3s, 2H each s), 5.45 (dd,
1H, J ) 2.6, 12.5 Hz), 6.48 (s, 1H), 7.05 (d, 2H, J ) 8.5 Hz), 7.41
(d, 2H, J ) 8.5 Hz); 13C NMR (75 MHz, DMSO-d6) δ 14.65, 22.70,
24.99, 45.60, 56.26, 56.72, 78.26, 94.42, 94.49, 95.74, 96.50,
107.72, 112.64, 116.78, 128.18, 133.18, 157.34, 157.52, 160.65,
161.46, 189.50. HRMS calcd for C24H31O8 [M + H]+, 447.2019;
found, 447.2014.
3-n-Propyl-2-hydroxy-4,6-bis(methoxymethoxy)acetophe-
1
none (5b). Yield: 68%. H NMR (300 MHz, DMSO-d6) δ 0.86
(br t, 3H, J ) 7.3 Hz), 1.42 (m, 2H), 2.49 (br t, 2H, J ) 7.3 Hz),
2.61 (s, 3H), 3.37 and 3.43 (2s, 3H each s), 5.27 and 5.29 (2s, 2H
each s), 6.34 (s, 1H), 13.84 (s, 1H); 13C NMR (75 MHz, DMSO-
d6) δ 14.72, 22.46, 24.56, 33.71, 56.74, 57.20, 92.10, 94.39, 95.17,
106.74, 111.35, 159.13, 161.42, 163.39, 204.30. HRMS calcd for
C15H21O6 [M - H]-, 297.1338; found, 297.1346.
7. General Procedure for the Preparation of 8-Alkylnarin-
genins (8a-j). To a stirring solution of 8-alkyl-5,7,4′-tris-
(methoxymethoxy)flavanone (7a-j) in MeOH (15 mL/mmol), 3
M HCl (5 mL/mmol) was added dropwise.40 The reaction mixture
was heated to reflux for 1 h (or until completion of the reaction, as
monitored by TLC). The mixture was then poured into H2O and
extracted with Et2O. The combined organic layers were washed
with brine, dried over anhydrous MgSO4, and concentrated under
reduced pressure. The residue was purified by column chromatog-
raphy (hexane/EtOAc), to afford 8a-j.
5. General Procedure for the Preparation of 3′-Alkyl-2′-
hydroxy-4,4′,6′-tris(methoxymethoxy)chalcones (6a-j). A solu-
tion of 3-alkyl-2-hydroxy-4,6-bis(methoxymethoxy)acetophenone
(5a-j) and p-methoxymethoxybenzaldehyde (1.1 equiv, synthesized
from p-hydroxybenzaldehyde) in EtOH (2.5 mL/mmol 5a-j),
cooled to 5 °C, was added dropwise to a stirring mixture of KOH
(0.7 g/mmol 5a-j) in H2O-EtOH (1.5 mL/mmol 5a-j, 2:3 v/v)
at 0 °C.40 The reaction mixture was stirred at 0 °C for 3 h and then
allowed to warm to room temperature and stirred for an additional
20 h (or until completion of the reaction, as monitored by TLC).
The reaction mixture was then poured into ice water, and the
resulting solution was acidified with 1 M HCl to pH 4 and extracted
with Et2O. The combined organic phases were washed with brine,
dried over anhydrous MgSO4, and concentrated under reduced
pressure. The residue was purified by column chromatography
(hexane/EtOAc) to afford 6a-j.
3′-Methyl-2′-hydroxy-4,4′,6′-tris(methoxymethoxy)chalcone (6a).
Yield: 74%. 1H NMR (300 MHz, DMSO-d6) δ 1.96 (s, 3H), 3.37,
3.39 and 3.42 (3s, 3H each s), 5.24, 5.29 and 5.33 (3s, 2H each s),
6.42 (s, 1H), 7.08 (d, 2H, J ) 8.8 Hz), 7.67 (d, 2H, J ) 8.8 Hz),
7.70 (d, 1H, J ) 15.8 Hz), 7.79 (d, 1H, J ) 15.8 Hz), 13.60 (s,
1H); 13C NMR (75 MHz, DMSO-d6) δ 8.31, 56.44, 56.74, 57.23,
93.30, 94.36, 94.62, 95.89, 107.27, 107.91, 117.22, 126.02, 129.04,
130.93, 143.14, 158.12, 159.43, 161.14, 163.10, 193.49. HRMS
calcd for C22H25O8 [M - H]-, 417.1549; found, 417.1535.
3′-Propyl-2′-hydroxy-4,4′,6′-tris(methoxymethoxy)chalcone (6b).
Yield: 83%. 1H NMR (300 MHz, DMSO-d6) δ 0.87 (br t, 3H, J )
7.3 Hz), 1.45 (m, 2H), 2.48 (br t, 2H, J ) 7.0 Hz), 3.36, 3.39 and
3.43 (3s, 3H each s), 5.24, 5.29 and 5.34 (3s, 2H each s), 6.40 (s,
1H), 7.08 (d, 2H, J ) 8.8 Hz), 7.67 (d, 2H, J ) 8.8 Hz), 7.70 (d,
1H, J ) 15.8 Hz), 7.80 (d, 1H, J ) 15.8 Hz), 13.66 (s, 1H); 13C
NMR (75 MHz, DMSO-d6) δ 14.76, 22.51, 24.74, 56.43, 56.76,
57.25, 92.99, 94.33, 94.44, 95.86, 107.70, 111.83, 117.21, 126.00,
1
8-Methylnaringenin (8a). Yield: 93%. H NMR (300 MHz,
DMSO-d6) δ 1.84 (s, 3H), 2.70 (dd, 1H, J ) 2.9, 16.9 Hz), 3.19
(dd, 1H, J ) 12.6, 16.9 Hz), 5.41 (dd, 1H, J ) 2.9, 12.6 Hz), 5.96
(s, 1H), 6.78 (d, 2H, J ) 8.5 Hz), 7.30 (d, 2H, J ) 8.5 Hz), 9.57,
10.75 and 12.08 (3s, 1H each s); 13C NMR (75 MHz, DMSO-d6)
δ 8.30, 42.51, 78.72, 95.76, 102.38, 103.21, 115.86, 128.72, 129.87,
158.26, 160.48, 161.63, 165.32, 197.40. HRMS calcd for C16H13O5
[M - H]-, 285.0763; found, 285.0754. Anal. (C16H14O5) C, H.
8-n-Propylnaringenin (8b). Yield: 88%. 1H NMR (300 MHz,
DMSO-d6) δ 0.80 (br t, 3H, J ) 7.3 Hz), 1.39 (m, 2H), 2.37 (br t,
2H, J ) 7.3 Hz), 2.70 (dd, 1H, J ) 2.9, 16.9 Hz), 3.16 (dd, 1H, J
) 12.5, 16.9 Hz), 5.39 (dd, 1H, J ) 2.9, 12.5 Hz), 5.96 (s, 1H),
6.78 (d, 2H, J ) 8.8 Hz), 7.29 (d, 2H, J ) 8.8 Hz), 9.57, 10.65
and 12.12 (3s, 1H each s); 13C NMR (75 MHz, DMSO-d6) δ 14.54,
22.60, 24.56, 42.65, 78.69, 95.90, 102.39, 108.18, 115.87, 128.54,
130.01, 158.22, 160.67, 161.77, 165.31, 197.46. HRMS calcd for
C18H17O5 [M - H]-, 313.1076; found, 313.1061. Anal. (C18H18O5)
C, H.
For experimental synthetic procedures and spectroscopic data
of other compounds, see Supporting Information.
Competition-Based Ligand Binding Assay. Ligand binding was
determined using a scintillation proximity assay with streptavidin-
coated polyvinyltoluene scintillation beads (Amersham, catalog No.
RPNQ0007) and biotinylated receptor. The recombinant biotin-
labeled ligand-binding domains (LBDs) of hERR and hERâ were
produced at high levels in E. coli and extracted with buffer
containing 100 mM Tris-HCl pH 8.0, 100 mM KCl, 10% glycerol,