S.Y. Park et al. / European Journal of Medicinal Chemistry 143 (2018) 390e401
399
J ¼ 8.0 Hz, 2H), 7.24 (s, 1H), 6.60 (s, 1H), 4.74 (s, 2H), 3.91 (s, 3H),
3.06 (s, 3H). 13C NMR (125 MHz, CDCl3)
171.4, 167.0, 160.0, 155.3,
3.53e3.48 (m, 2H), 3.07 (s, 3H), 1.25 (t, J ¼ 7.5 Hz, 3H). 13C NMR
d
(125 MHz, CDCl3) d 167.2, 160.8, 155.1, 139.8, 134.4, 128.5, 127.8,
141.5,130.4,129.7,128.7,127.5,110.6,110.5,105.2, 52.4, 50.9, 37.1. ESI
127.6, 110.5, 110.1, 110.0, 105.3, 35.1, 15.0. ESI MS (m/e) 363.11
MS (m/e) 350.07 [Mþ1]þ.
[Mþ1]þ. Purity: 95.4% by HPLC.
4.1.5. General procedure for the synthesis of compounds (29a and
29b)
4.1.6.4. 5-Chloro-2,4-dihydroxy-N-methyl-N-(4-(propylcarbamoyl)
benzyl)benzamide (30c). 46% yield. Rf ¼ 0.21 (7:3 ethyl acetate:
A methyl benzoate derivatives (28a and 28b) (1 equiv) and 20%
(w/v) lithium hydroxide in methanol-H2O (1:1) was stirred at room
temperature for 3 h. The mixture was neutralized with 6 N HCl to
pH 6 and then extracted with ethyl acetate three times. The organic
layer was dried over Na2SO4, concentrated under reduced pressure
and purified by MPLC (Biotage SNAP HP-Sil column) to afford
compound 29a and 29b in 85 and 88% yield.
methanol). 1H NMR (500 MHz, (CD3)2SO)
d 10.37 (s, 1H), 10.11 (s,
1H), 8.46 (t, J ¼ 5.5 Hz, 1H), 7.83 (d, J ¼ 8.0 Hz, 2H), 7.38 (s, 2H), 7.13
(s, 1H), 6.59 (s, 1H), 4.67 (s, 2H), 3.21 (t, J ¼ 6.0 Hz, 2H), 2.79 (s, 3H),
1.55e1.48 (m, 2H), 0.87 (t, J ¼ 7.5 Hz, 3H). 13C NMR (125 MHz,
(CD3)2SO) d 168.6, 166.4, 154.9,153.9, 141.0, 134.1, 129.4, 127.9, 127.5,
116.9, 110.5, 104.0, 49.9, 41.5, 36.3, 23.0, 12.0. ESI MS (m/e) 377.12
[Mþ1]þ. Purity: 95.6% by HPLC.
4.1.5.1. 4-((5-Chloro-2,4-dihydroxy-N-methylbenzamido)methyl)
4.1.6.5. 2,4-Dihydroxy-5-isopropyl-N-methyl-N-(4-(methyl-
benzoic acid (29a). 85% yield. Rf ¼ 0.19 (1:1 ethyl acetate: hexane).
carbamoyl)benzyl)-benzamide (30d). 36% yield. Rf ¼ 0.21 (7:3 ethyl
1H NMR (500 MHz, CD3OD)
d
8.00 (d, J ¼ 8.0 Hz, 2H), 7.43 (s, 2H),
acetate: methanol). 1H NMR (500 MHz, (CD3)2SO)
d 9.66 (s, 1H),
7.18 (s, 1H), 6.50 (s, 1H), 7.74 (s, 2H), 2.94 (s, 3H). 13C NMR (125 MHz,
9.53 (s, 1H), 8.43 (d, J ¼ 4.5 Hz, 1H), 7.81 (d, J ¼ 8.0 Hz, 2H), 7.35 (s,
2H), 6.88 (s,1H), 6.39 (s, 1H), 4.60 (s, 2H), 3.07e3.05 (m, 1H), 2.82 (s,
1H), 2.78 (d, J ¼ 4.0 Hz, 3H), 2.06 (d, J ¼ 2.0 Hz, 6H). 13C NMR
CD3OD)
d 171.8, 169.7, 156.5, 155.2, 143.4, 131.1, 130.8, 130.1, 128.5,
117.0, 112.6, 104.6. ESI MS (m/e) 336.06 [Mþ1]þ.
(125 MHz, (CD3)2SO)
d 170.7, 167.0, 156.8, 153.4, 141.3, 134.0, 127.6,
4.1.5.2. 4-((2,4-Dihydroxy-5-isopropyl-N-methylbenzamido)methyl)
127.5, 126.1, 114.6, 103.0, 51.9, 35.2, 26.7, 26.7, 26.4, 23.1. ESI MS (m/
benzoic acid (29b). 88% yield. Rf ¼ 0.28 (1:1 ethyl acetate: hexane).
e) 357.18 [Mþ1]þ. Purity: 95.4% by HPLC.
1H NMR (500 MHz, CD3OD)
d
8.00 (d, J ¼ 8.5 Hz, 2H), 7.41 (d,
J ¼ 6.5 Hz, 2H), 6.99 (s, 1H), 6.35 (s, 1H), 4.73 (s, 2H), 3.17e3.11 (m,
4.1.6.6. N-(4-(Ethylcarbamoyl)benzyl)-2,4-dihydroxy-5-isopropyl-N-
1H), 2.97 (s, 1H), 1.17e1.11 (m, 6H). 13C NMR (125 MHz, CD3OD)
methyl-benzamide (30e). 24% yield. Rf ¼ 0.21 (7:3 ethyl acetate:
d
173.9, 169.6, 158.6, 154.7, 143.9, 131.1, 131.0, 128.4, 128.0, 126.9,
methanol). 1H NMR (500 MHz, (CD3)2SO)
d 9.61 (s, 1H), 9.49 (s, 1H),
114.6, 103.3, 27.5, 23.0. ESI MS (m/e) 344.14 [Mþ1]þ.
8.42 (t, J ¼ 5.0 Hz, 1H), 7.78 (d, J ¼ 8.0 Hz, 2H), 7.31 (s, 2H), 6.85 (s,
1H), 6.36 (s, 1H), 4.56 (s, 2H), 3.27e3.22 (m, 2H), 3.04e2.99 (m, 1H),
2.78 (s, 3H), 1.07 (t, J ¼ 7.0 Hz, 3H), 1.03 (d, J ¼ 4.0 Hz, 6H). 13C NMR
4.1.6. General procedure for preparing bendzamide derivatives (28b
and 30a-f)
(125 MHz, (CD3)2SO)
d 170.0, 165.6, 156.1, 152.7, 140.5, 133.5, 127.1,
The benzoic acid derivatives (25 and 29a-b) (1 equiv) was added
126.8, 125.4, 113.9, 102.3, 79.0, 51.2, 34.4, 33.9, 25.7, 22.4, 14.6. ESI
to
a
primary alkyl amines (1.5 equiv), 1-ethyl-3-(3-
(2 equiv), 1-
MS (m/e) 357.18 [Mþ1]þ. Purity: 96.6% by HPLC.
dimethylaminopropyl)carbodiimide
hydroxybenzotriazole monohydrate (1 equiv) and N,N-diisopro-
pylethylamine (1 equiv) in DMF. The reaction mixture was stirred
under microwave irradiation at 120 ꢀC for 3 h. After completion of
the reaction, the mixture was dissolved in ethyl acetate. The organic
layer was washed with saturated 1N-HCl three times, dried over
Na2SO4, concentrated under reduced pressure and purified by
MPLC to afford compounds 28b and 30a-f in 17e82% yield.
4.1.6.7. 2,4-Dihydroxy-5-isopropyl-N-methyl-N-(4-(propylcarba-
moyl)benzyl)-benzamide (30f). 22% yield. Rf ¼ 0.21 (7:3 ethyl ace-
tate: methanol). 1H NMR (500 MHz, (CD3OD)
d
7.81 (dd, J ¼ 6.3 Hz,
1.5 Hz, 2H), 7.41 (d, J ¼ 5.5 Hz, 2H), 6.99 (s, 1H), 6.35 (s, 1H), 4.72 (s,
2H), 3.33 (t, J ¼ 7.5 Hz, 2H), 3.16e3.13 (m,1H), 2.96 (s, 3H),1.66e1.61
(m, 2H), 1.12 (d, J ¼ 7.5 Hz, 6H), 0.97 (t, J ¼ 7.5 Hz, 3H). 13C NMR
(125 MHz, CD3OD)
d 173.9, 169.9, 158.5, 154.6, 142.2, 134.9, 128.6,
128.6, 127.9, 126.9,114.6, 103.3, 42.8, 24.5, 23.7, 23.1, 11.8. ESI MS (m/
4.1.6.1. Methyl 4-((2,4-dihydroxy-5-isopropyl-N-methylbenzamido)-
e) 371.19 [Mþ1]þ. Purity: 95.5% by HPLC.
methyl)benzoate (28b). 82% yield. Rf ¼ 0.13 (3:7 ethyl acetate:
hexane). 1H NMR (500 MHz, CDCl3)
d
10.42 (s, 1H), 8.09 (d,
4.2. Molecular modeling
J ¼ 8.5 Hz, 2H), 7.39 (d, J ¼ 8.5 Hz, 2H), 7.06 (s,1H), 6.41 (s, 1H), 6.10
(s, 1H), 4.79 (s, 2H), 3.94 (s, 3H), 3.10 (s, 3H), 3.07e3.03 (m, 1H), 0.97
In silico docking of 21a or 30f with the 3D coordinates of the X-
ray crystal structures of the N-terminal domain of human Hsp90
(PDB code: 2XJX) was accomplished using the AutoDock program
downloaded from the Molecular Graphics Laboratory of the Scripps
Research Institute. In the docking experiments carried out, gas-
teiger charges were placed on the X-ray structures of the N-ter-
minal domain of Hsp90 along with 21a or 30f using tools from the
AutoDock suite. A grid box centered on the N-terminal Hsp90
domain with definitions of 60_60_60 points and 0.375 Å spacing
was chosen for ligand docking experiments. The docking parame-
ters consisted of setting the population size to 150, the number of
generations to 27000, and the number of evaluations to 25000000,
while the number of docking runs was set to 100 with a cutoff of 1 Å
for the root-mean-square tolerance for the grouping of each
docking run. The docking model of human Hsp90 with compound
21a and 30f were depicted in Figs. 2 and 4, respectively and
rendering of the picture was generated using PyMol (DeLano
Scientific).
(d, J ¼ 6.5 Hz, 6H). 13C NMR (125 MHz, CDCl3)
d 173.4, 167.0, 159.7,
157.4, 142.2, 130.4, 129.6, 127.1, 126.4, 126.0, 108.8, 104.0, 52.4, 36.7,
26.2, 22.9, 22.6. ESI MS (m/e) 358.16 [Mþ1]þ.
4.1.6.2. 5-Chloro-2,4-dihydroxy-N-methyl-N-(4-(methylcarbamoyl)
benzyl)benzamide (30a). 17% yield. Rf ¼ 0.21 (4:1 ethyl acetate:
methanol). 1H NMR (500 MHz, (CD3)2SO)
d 10.36 (s, 1H), 10.11 (s,
1H), 8.43 (dd, J ¼ 8.8 Hz, 4 Hz, 1H), 7.77 (d, J ¼ 8.0, 2H), 7.36 (s, 2H),
7.12 (s, 1H), 6.57 (s, 1H), 4.66 (s, 1H), 2.79e2.77 (m, 6H). 13C NMR
(125 MHz, (CD3)2SO)
d 168.5, 166.9, 154.8, 153.8, 141.0, 133.9, 129.3,
127.8, 127.6, 116.9, 110.5, 104.0, 50.0, 36.3, 26.8. ESI MS (m/e) 349.09
[Mþ1]þ. Purity: 99.2% by HPLC.
4.1.6.3. 5-Chloro-N-(4-(ethylcarbamoyl)benzyl)-2,4-dihydroxy-N-
methylbenzamide (30b). 31% yield. Rf ¼ 0.21 (4:1 ethyl acetate:
methanol). 1H NMR (500 MHz, CDCl3)
(d, J ¼ 8.0 Hz, 2H), 7.25 (s, 1H), 6.66 (s, 1H), 6.11 (s, 1H), 4.74 (s, 2H),
d
7.76 (d, J ¼ 8.0 Hz, 2H), 7.34