4
T. Shoda et al. / Bioorg. Med. Chem. xxx (2016) xxx–xxx
Table 1
5.1.1. {4-[2-(Decylamino)ethoxy]phenyl}[6-hydroxy-2-(4-
hydroxyphenyl)benzo[b]thiophen-3-yl]methanone (8, RC10)
Compound (49.6 mg, 0.117 mmol) and sodium iodide
Estrogen receptor binding affinities and ER
activities of compounds
a
degradation
4
a
Compound
IC50 (nM)
(353.4 mg, 2.36 mmol) were dissolved in 1 ml acetone. Reaction
was conducted using microwave irradiation at 56 °C for 24 h. The
solvent was evaporated, AcOEt was added, and the organic layer
was washed with water and brine. The solvent was evaporated
and the residue was dissolved in methanol to transfer to the reac-
tion vial. Then, decylamine (21.9 mg, 0.14 mmol) and triethy-
lamine (31.5 mg, 0.31 mmol) were added. The mixture was
stirred and heated in microwave apparatus (Initiater, Biotage) at
RC6
RC8
61
49
40
5.9
28
RC10
RC12
RC14
RC16
RC18
Raloxifene
11
1.8
0.47
2.4
b
Compound 18
1
20 °C until the reaction was completed. The mixture was evapo-
a
The IC50 values for each competing ligand were
calculated according to the sigmoidal inhibition curves.
rated in vacuo and the products were purified by silica gel chro-
matography (MeOH/DCM = 8/92). Yield = 28.8 mg, 45%. Pale
yellow viscous compound; IR: 3284, 2925, 2850, 1594, 1459,
b
0
23
4
,4 -(Heptane-4,4-diyl)bis(2-methylphenol).
ꢀ1
1
1
250, 1166, 1026, 823, 617, 524, 510, 462, 435, 401 cm ; H
3
NMR (400 MHz, CD OD) d 7.70 (2H, d, J = 8.8 Hz), 7.41 (1H, d,
4
. Conclusion
J = 8.8 Hz), 7.26 (1H, d, J = 2.0 Hz), 7.17 (2H, d, J = 8.8 Hz), 6.83–
.87 (3H, m), 6.61 (2H, d, J = 8.4 Hz), 4.08 (2H, t, J = 5.0 Hz), 2.97
2H, t, J = 5.2 Hz), 2.64 (2H, t, J = 7.6 Hz), 1.52 (2H, m), 1.25–1.30
6
In summary, we report the design and synthesis of raloxifene
derivatives with long alkyl chains at the amine moiety, as potential
SERD candidates. All seven compounds were able to bind ER , but
only two had the ability to down-regulate ER . These findings sug-
(
(
13
14H, m), 0.89 (3H, t, J = 7.0 Hz); C NMR (150 MHz, CD
3
OD) d
a
1
1
1
2
5
95.53, 164.49, 159.29, 156.79, 143.96, 141.38, 134.22, 133.42,
31.80, 131.32, 131.13, 125.94, 124.64, 116.44, 116.02, 115.27,
a
gest that the ligand core is replaceable, and that introducing the
appropriate length of alkyl chain on the amine moiety of the ligand
core produces efficacious SERDs. Furthermore, these compounds
showed antagonistic activities, and the potency of our compounds
was superior to that of an antagonist that binds ER with high affin-
ity, but is not able to down-regulate ER. These results provide use-
ful information for the development of promising SERD candidates.
As a result of these findings, we are currently working on another
type of ligand core to further investigate promising SERD
candidates.
07.84, 67.84, 32.99, 30.70, 30.62, 30.52, 30.38, 30.03, 28.22,
+
[M+H]+
4
3.67, 14.37; HRMS (ESI+) m/z calcd for C33H40NO S
46.2673, found 546.2648.
5
.1.2. {4-[2-(Hexylamino)ethoxy]phenyl}[6-hydroxy-2-(4-
hydroxyphenyl)benzo[b]thiophen-3-yl]methanone (6, RC6)
The same procedure as for RC10 was used, but starting from
hexylamine.
Yield = 13.7 mg, 58%. Pale yellow viscous compound; IR: 3332,
2
4
927, 2857, 1595, 1253, 1034, 814, 754, 492, 489, 485, 445,
ꢀ
1
1
35 cm
3
; H NMR (400 MHz, CD OD) d 7.73–7.75 (2H, m), 7.43
5
5
. Experimental
(
6
(
1
1H, d, J = 8.8 Hz), 7.26 (1H, d, J = 2.0 Hz), 7.17–7.19 (2H, m),
.91–6.93 (2H, m), 6.85–6.88 (1H, m), 6.59–6.62 (2H, m), 4.27
2H, t, J = 5.0 Hz), 3.43 (2H, t, J = 4.8 Hz), 3.05 (2H, t, J = 8.0 Hz),
.66–1.73 (2H, m), 1.42–1.28 (6H, m), 0.92 (3H, t, J = 6.8 Hz); 13
NMR (150 MHz, CD OD) d 193.98, 162.00, 157.84, 155.43, 142.87,
.1. Chemistry
C
All reagents and solvents were purchased from Sigma–Aldrich,
3
Wako Pure Chemical, and Tokyo Chemical Industry and were used
without purification. Analytical TLC was conducted using Merck
silica gel 60 F254 pre-coated plates and visualized using a
1
40.06, 132.05, 130.01, 123.24, 115.01, 114.66, 113.94, 106.45,
1
05.00, 63.27, 30.95, 25.80, 25.69, 22.01, 12.82; HRMS (ESI+) m/z
+
+
4
calcd for C29H32NO S [M+H] 490.2047, found 490.2028.
2
54 nm UV lamp, phosphomolybdic acid, p-anisaldehyde, or nin-
hydrin stains. Column chromatography was performed using silica
gel (spherical, neutral) purchased from Kanto Chemical. Micro-
5
.1.3. [6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl]
{
4-[2-(octylamino)ethoxy]phenyl}methanone (7, RC8)
1
wave reactions were conducted using a Biotage Initiater. H NMR
The same procedure as for RC10 was used, but starting from
1
3
and C NMR spectra were measured using a Varian AS 400
Mercury spectrometer or Varian 600 MHz NMR spectrometer.
Chemical shifts are expressed in ppm downfield from a solvent
residual peak or internal standard tetramethylsilane (TMS). FT-IR
spectra were measured using a JASCO FT-IR 4100 equipped with
octylamine.
Yield = 36.1 mg, 62%. Pale yellow viscous compound; IR: 3296,
928, 2853, 1599, 1257, 1171, 1033, 830, 533, 499, 488,
2
4
ꢀ1
1
35 cm
3
; H NMR (400 MHz, CD OD) d 7.71–7.73 (2H, m), 7.43
(
6
(
(
1H, d, J = 8.8 Hz), 7.27(1H, d, J = 2.4 Hz), 7.16–7.18 (2H, m), 6.85–
.91 (3H, m), 6.60–6.62 (2H, m), 4.22 (2H, t, J = 4.8 Hz), 3.29–3.32
2H, m), 2.94 (2H, t, J = 7.8 Hz), 1.61–1.67 (2H, m), 1.29–1.35
an ATR unit as a sampling module, and were expressed in
m
ꢀ1
(
cm ). High-resolution mass spectra were measured using a
Shimadzu IT-TOF MS equipped with an electrospray ionization
13
10H, m), 0.90 (3H, t, J = 6.8 Hz); C NMR (150 MHz, CD
3
OD) d
source. Compounds 1–4 were prepared according to a previously
1
1
1
2
5
95.42, 163.57, 159.20, 156.77, 144.22, 141.42, 134.19, 133.43,
32.42, 131.38, 131.30, 131.00, 125.98, 124.64, 116.42, 116.05,
15.35, 107.87, 65.18, 32.83, 30.16, 30.12, 27.61, 27.56, 23.65,
3.61, 14.35; HRMS (ESI+) m/z calcd for C31
2
1
reported method.
+
[M+H]+
H36NO
4
S
18.2360, found 518.2321.
Table 2
The IC50 values of compounds
5
.1.4. (4-(2-(Dodecylamino)ethoxy)phenyl)(6-hydroxy-2-(4-
hydroxyphenyl)benzo[b]thiophen-3-yl)methanone (9, RC12)
The same procedure as for RC10 was used, but starting from
dodecylamine.
Compound
IC50 (nM)
RC10
RC12
0.68
0.09
Yield = 24.1 mg, 40%. Pale yellow viscous compound; IR: 3318,
2
3
18
4.9
2
926, 2856, 1602, 1460, 1258, 1172, 1035, 825, 658, 491, 460,