Synthesis and antitumor activity of 5-[1-(3-(dimethylamino)propyl)-5- halogenated-2-oxoindolin-(3Z)-ylidenemethyl]-2,4-dimethyl-1H-pyrrole-3- carboxamides

Article abstract of DOI:10.1016/j.bmcl.2011.03.031

We report herein the design and synthesis of novel 1-[3-(dimethylamino) propyl]indolin-2-one derivatives based on the structural features of Sunitinib, a known multitargeted receptor tyrosine kinase inhibitor, and TMP-20, a previously discovered compound with good antitumor activity in our lab. These newly synthesized derivatives were evaluated for in vitro activity against five human cancer cell lines and VEGF/bFGF-stimulated HUVECs. Results revealed that all of the target compounds 1a-p show potent antitumor activity, compounds 1e-h (IC₅₀'s: 0.45-5.08 μM) are more active than Sunitinib (IC ₅₀'s: 1.35-6.61 μM), and the most active compound 1h (IC ₅₀: 0.47-3.11 μM) is 2.1-4.6-fold more potent than Sunitinib against all five cancer cell lines. In addition, like Sunitinib, 1a-p have higher selectivity on VEGF-stimulated HUVEC other than bFGF-stimulated HUVEC.

Full text of DOI:10.1016/j.bmcl.2011.03.031

Bioorganic & Medicinal Chemistry Letters 21 (2011) 3062–3065
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and antitumor activity of 5-[1-(3-(dimethylamino)propyl)-5-haloge-
nated-2-oxoindolin-(3Z)-ylidenemethyl]-2,4-dimethyl-1H-pyrrole-3-
carboxamides
Kai Lv a,b, Li-Li Wang a, Ming-Liang Liu b, , Xin-Bo Zhou a, Shi-Yong Fan a, Hong-Ying Liu a, Zhi-Bing Zheng a,
,
⇑
⇑
Song Li a
a Beijing Institute of Pharmacology and Toxicology, Beijing 100850, PR China
b Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
We report herein the design and synthesis of novel 1-[3-(dimethylamino)propyl]indolin-2-one derivatives
based on the structural features of Sunitinib, a known multitargeted receptor tyrosine kinase inhibitor, and
TMP-20, a previously discovered compound with good antitumor activity in our lab. These newly synthe-
sized derivatives were evaluated for in vitro activity against five human cancer cell lines and VEGF/bFGF-
stimulated HUVECs. Results revealed that all of the target compounds 1a–p show potent antitumor activity,
Received 28 January 2011
Revised 1 March 2011
Accepted 9 March 2011
Available online 16 March 2011
compounds 1e–h (IC50’s: 0.45–5.08
most active compound 1h (IC50: 0.47–3.11
cancer cell lines. In addition, like Sunitinib, 1a–p have higher selectivity on VEGF-stimulated HUVEC other
than bFGF-stimulated HUVEC.
l
M) are more active than Sunitinib (IC50’s: 1.35–6.61
lM), and the
Keywords:
Indolin-2-ones
Synthesis
lM) is 2.1–4.6-fold more potent than Sunitinib against all five
Antitumor activity
Ó 2011 Elsevier Ltd. All rights reserved.
Indolin-2-ones are an important class of compounds with potent
antitumor activity, and structural modifications mainly at the 3- and
5-positions of the indolin-2-one ring have recently led many deriv-
atives possessing more potent inhibition on different receptors.1,2
Semaxanib (SU5416, Fig. 1), the first synthetic indolin-2-one
small-molecule compound showed potent activity against vascular
endothelial growth factor (VEGF) receptor-1 and -2 tyrosine ki-
nases,3,4 but the development of Semaxanib was ceased due to the
severe toxicity and negative results in Phase II/III studies.5,6 Sun
et al. synthesized a series of novel derivatives by introduction halo-
gens (F, Cl or Br) and basic side chains at the C-5 position of the indo-
lin-2-one ring and C-40position of the pyrrole ring of SU5416
respectively, and found Sunitinib (Su11248, Fig. 1) to be a new mult-
itargeted receptor tyrosine kinase inhibitor7 which has activity
against many human cancer cell lines.8–12 The US Food and Drug
Administration (FDA) approved Sunitinib for the treatment of ad-
vanced renal cancer and gastrointestinal stromal tumor (GIST) after
disease progression on or intolerance to Imatinib mesylate in Janu-
ary 2006.13
Y
4'
N
H
N
H
O
X
X
O
N
H
N
R
N CH2
)
Semaxanib (X = Y = H)
Et N(CH ) NHCO)
Z24 (X = H, R =
Sunitinib (X = F, Y =
2
2 2
TMP-20 (X = Cl, R = Me2N(CH2 )3)
Figure 1. Structures of some indolin-2-ones.
pression of various types of tumors in vivo.14–16 TMP-20 (Fig. 1), a
novel derivative with a 3-(dimethylamino)propyl group and a chlo-
rine atom at the N-1 and C-5 positions of indolin-2-one ring respec-
tively, was also discovered in our lab. Compared with Z24 (a
Mannich base), TMP-20 has more chemical stability while retaining
the good antitumor activity of Z24 (not published).
Z24 (Fig. 1) with a piperidin-1-ylmethyl group at the N-1 position
of indolin-2-one ring was designed and synthesized by our lab. It can
inhibit angiogenesis in new blood vessels, resulting in growth sup-
As part of our continuing investigation of indolin-2-ones as po-
tential antitumor drug candidates, we planned to design and synthe-
size
a series of novel indolin-2-one derivatives. This design
combined the structural features of Sunitinib and TMP-20: a 3-
(dimethylamino)propyl group and a halogen atom (F or Cl) at the
N-1 and C-5 positions of indolin-2-one ring respectively, and diver-
sified substituted carbamoyl groups at the C-40position of the pyr-
⇑
Corresponding authors. Tel./fax: +86 10 63036965 (M.-L.L.); tel./fax: +86 10
66931642 (Z.-B.Z.).
E-mail addresses: lmllyx@yahoo.com.cn (M.-L. Liu), zzbcaptain@yahoo.com.cn
(Z.-B. Zheng).
0960-894X/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmcl.2011.03.031

K. Lv et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3062–3065
3063
O
O
MeCOCH2CO2Et
O
O
OEt
HCl, EtOH
OEt
O
O
NaNO2
Zn, HOAc
DMF, POCl3
OBu-t
65 oC, 3h, 46% t-BuO2C
(for two steps)
Cl(CH2)2Cl
70 oC, 3h, 91%
HOAc
rt, 3h
OBu-t
O
N
H
N
H
5
N
ref., 2h, 82%
HO
2
3
4
O
O
N
8a: Z = NMe2
8e: Z=
8f
OEt
OH
Z
ZH
H
KOH
N
N
N
8b
: Z = NEt2
: Z = NH(CH2)2NMe2
: Z=
8g
H
H
EDC, HOBt
MeOH-H2O
ref., 3h, 94%
N
H
N
N
H
8c
N Me
N Et
: Z=
rt, 12h, 35-56%
H
O
O
O
8d: Z = NH(CH2)2NEt2
6
7
8
8h: Z=
Scheme 1. Synthesis of pyrrole-4-carboxamides 8a–h.
NNH2
O
O
X
X
X
X
Me2N(CH2)3Cl
NH2NH2
ref., 1h, 90-93%
EtOH/EtONa
O
O
N
O
N
H
KF-Al2O3/MeCN
ref.,10h, 46-51%
N
H
ref., 5h, 75-80%
N
H
N
12a,b
10a,b
11a,b
9a,b
9a-12a: X = F
9b-12b: X = Cl
O
Z
N
N
N
N
1i: X = F, Z =
1a: X = F, Z = NMe2, n = 1
, n = 1
, n = 1
, n = 1
, n = 1
1j: X = Cl, Z =
1k: X = F, Z =
1l: X = Cl, Z =
1b: X = Cl, Z = NMe2, n = 1
N
H
O
1) 8a-h, EtOH, ref., 2h
X
1c: X = F, Z = NEt2, n = 1
nHCl
2) HCl/Et2O, rt, 30 min
50-75% (for two steps)
N
1d: X = Cl, Z = NEt2, n = 1
N
1a-p
1e: X = F, Z = NH(CH2)2NMe2, n = 2
1f: X = Cl, Z = NH(CH2)2NMe2, n = 2
1g: X = F, Z = NH(CH2)NEt2, n = 2
1h: X = Cl, Z = NH(CH2)NEt2, n = 2
1m: X = F, Z =
1n: X = Cl, Z =
1o: X = F, Z =
1p: X = Cl, Z =
N
N
N
N
NMe
, n = 2
, n = 2
, n = 2
NMe
N Et
N Et, n = 2
Scheme 2. Synthesis of novel indolin-2-ones 1a–p.
role ring. Our primary objective was to optimize the potency of these
compounds against human cancer cell lines. A structure–activity
relationship (SAR) study was also explored to facilitate the further
development of the indolin-2-one derivatives.
tics.18 As expected, the pyrrole-2-methylidene geometry at the 3-po-
sition of indolin-2-one ring was confirmed to have the Z-
configuration by NOE NMR experiments.
All the newly synthesized indolin-2-ones 1a–p were evaluated
for in vitro antitumor activity in five human cancer cell lines,
including IM-9 (B-lymphoblastoid), A549 (lung adenocarcinoma),
HL-60 (promyelocytic leukemia), K-562 (erythromyeloblastoid)
and MDA-MB-231 (breast cancer) using standard MTT assay.19
The 50% inhibition concentrations (IC50’s) were compared with
those of Sunitinib (Table 1).
Detailed synthetic pathways to pyrrole-3-carboxamides 8a–h
and indolin-2-ones 1a–p are depicted in Schemes 1 and 2, respec-
tively. According to well-established literature procedures,7 con-
densation of commercially available tert-butyl acetoacetate (2)
with sodium nitrite in acetic acid gave oxime 3, and subsequently
reductive cyclization with ethyl acetoacetate yielded bis-ester 4.
Elective hydrolytic decarboxylation of 4 and then formylation
afforded aldehyde 6. Base hydrolysis of the ethyl ester of 6 pro-
vided the key intermediate 5-formyl-2, 4-dimethylpyrrole-3-car-
boxylic acid 7, which upon amidation with different amines (ZH)
in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiim-
ide hydrochloride (EDC) and N-hydroxybenzotriazole (HOBt) was
converted to pyrrole-3-carboxamides 8a–h (Scheme 1).
The indolin-2-ones 1a–p have potent in vitro antitumor activity
against the tested human cancer cell lines. Among them, compouds
1e–h, 1n and 1p (IC50’s: 0.45–8.88
comparable to Sunitinib (IC50’s: 1.35–6.61
cell lines. In particular, compound 1h (IC50s: 0.47–3.11
l
M) are more potent than or
M) against all of the
M) was
l
l
found to be 2.1–4.6-fold more potent than the reference drug
against these cancer cell lines.
Reduction of the ketone moiety of isatins 9a,b via Wolff–Kishner–
Huang reaction gave indolin-2-ones 11a,b according to literature
procedures,17 which upon nucleophilic substitution with 1-chloro-
3-dimethylaminopropane hydrochloride in the presence of KF-
Al2O3 in refluxing acetonitrile was converted to 1-(3-dimethylamino-
propyl)indolin-2-ones 12a,b. Finally, the target compounds 1a–p
were prepared via aldol condensation of 12a,b with pyrrole-3-car-
boxamides8a–h, andfurther hydrochlorateformationwithhydrogen
chloride gas in diethyl ether (Scheme 2). All of the new synthesitic
compoundswere wellcharacterizedthroughthe spectralcharacteris-
According to the biological evaluation results, antitumor activ-
ity of the indolin-2-ones 1a–p depends mainly on the side chains
at the C-40position of the pyrrole ring. The relative contribution
of the Z moieties in linear side chains at the same position to anti-
tumor activity is as follows: NH(CH2)2NNEt2 ꢀ NH(CH2)2NMe2 >> -
NEt2 > NMe2, and the antitumor activity of the Z moieties in cyclic
side chains are in the order: 4-methyl-1-piperidinyl > 4-ethyl-1-
piperidinyl, 1-piperidinyl > 1-pyrrolidinyl. In addition, 5-chloric
indolin-2-ones are generally more active than the corresponding
5-fluoric analogs.

3064
K. Lv et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3062–3065
Table 1
In vitro activity of the target compounds 1a–p against selected cells
O
Z
N
H
O
X
nHCl
N
N
a
Cell lines
IC50 (lM)
Compounds
X
Z
n
IM-9
A549
HL-60
K-562
MDA-MB-231
HUVEC
bFGF
VEGF
1a
1b
1c
1d
1e
1f
F
Cl
F
Cl
F
Cl
F
–NMe2
–NMe2
–NEt2
–NEt2
–NH(CH2)2NMe2
–NH(CH2)2NMe2
–NH(CH2)2NEt2
–NH(CH2)2NEt2
1
1
1
1
2
2
2
2
17.95
9.42
14.12
6.28
1.36
0.45
1.63
0.47
25.19
16.01
29.89
13.09
2.94
3.52
5.08
3.11
14.83
7.30
10.66
4.02
2.73
1.17
1.82
1.07
13.60
6.74
4.88
2.07
1.46
0.53
1.33
0.52
19.22
12.03
13.74
6.82
2.14
2.44
19.85
8.27
10.45
4.87
1.42
3.36
1.68
3.08
5.23
1.62
3.96
2.90
0.48
1.11
0.71
2.72
1g
1h
2.86
2.29
Cl
N
N
N
N
1i
F
1
1
1
1
2
2
2
2
19.05
9.36
4.83
4.49
4.06
1.47
7.26
21.23
14.03
18.71
7.33
11.92
7.82
4.39
3.99
7.59
3.56
13.44
11.60
6.58
4.09
2.14
5.27
1.41
5.98
13.31
11.46
11.49
5.68
11.26
4.65
5.27
2.04
5.64
2.00
3.38
6.56
3.92
4.06
1.31
2.99
1.34
1.58
1j
Cl
F
1k
1l
Cl
F
1m
1n
1o
11.07
6.78
9.00
N
N
N
N
N Me
N Me
N Et
N Et
Cl
F
5.06
13.73
8.09
1p
Cl
2.25
1.35
8.88
6.61
2.62
3.53
2.45
2.41
3.46
4.51
1.77
4.04
1.02
2.75
Sunitinib
a
IC50 values were determined by at least three separate tests and reported as mean values.
3. Fong, T. A.; Shawver, L. K.; Sun, L.; Tang, C.; App, H.; Powell, T. J.; Kim, Y. H.;
Schreck, R.; Wang, X.; Risau, W.; Ullrich, A.; Hirth, K. P.; McMahon, G. Cancer
Res. 1999, 59, 99.
4. Shaheen, R. M.; Davis, D. W.; Liu, W.; Zebrowski, B. K.; Wilson, M. R.; Bucana, C.
D.; McConkey, D. J.; McMahon, G.; Ellis, L. M. Cancer Res. 1999, 59, 5412.
5. Longo, R.; Sarmiento, R.; Fanelli, M.; Capaccetti, B.; Gattuso, D.; Gasparini, G.
Angiogenesis 2002, 5, 237.
6. Kuenen, B. C.; Rosen, L.; Smit, E. F.; Parson, M. R.; Levi, M.; Ruijter, R.; Huisman, H.;
Kedde, M. A.; Noordhuis, P.; Vandervijgh, W. J.; Peters, G. J.; Cropp, G. F.; Scigalla,
P.; Hoekman, K.; Pinedo, H. M.; Giaccone, G. J. Clin. Oncol. 2002, 20, 1657.
7. Sun, L.; Liang, C.; Shirazian, S.; Zhou, Y.; Miller, T.; Cui, J.; Fukuda, J. Y.; Chu, J. Y.;
Nematalla, A.; Wang, X.; Chen, H.; Sistla, A.; Luu, T. C.; Tang, F.; Wei, J.; Tang, C.
J. Med. Chem. 2003, 46, 1116.
All compounds were also further examined for inhibitory activ-
ity against VEGF- or recombinant human basic fibroblast growth
factor (bFGF)- stimulated human umbilical venous endothelial
cells (HUVEC) proliferation using standard MTT assay19 and the re-
sults are reported in Table 1. Results suggested that the indolin-2-
ones 1a–p have higher selectivity on VEGF-stimulated HUVEC
(IC50’s: 0.48–6.56
lM) other than bFGF-stimulated HUVEC (IC50’s:
1.42–19.85 M), which is consistent with Sunitinib. Further stud-
l
ies on related mechanism of action and structural modifications
are currently in progress.
8. O’Farrell, A. M.; Abrams, T. J.; Yuen, H. A.; Ngai, T. J.; Louie, S. G.; Yee, K. W.;
Wong, L. M.; Hong, W.; Lee, L. B.; Town, A.; Smolich, B. D.; Manning, W. C.;
Murray, L. J.; Heinrich, M. C.; Cherrington, J. M. Blood 2003, 101, 3597.
9. Young, E.; Miele, L.; Tucker, K. B.; Huang, M.; Wells, J.; Gu, J. W. Cancer Biol. Ther.
2010, 10, 703.
10. Ikezoe, T.; Nishioka, C.; Tasaka, T.; Yang, Y.; Komatsu, N.; Togitani, K.; Koeffler,
H. P.; Taguchi, H. Mol. Cancer Ther. 2006, 5, 2522.
11. Lyros, O.; Mueller, A.; Heidel, F.; Schimanski, C. C.; Gockel, I.; Galle, P. R.; Lang,
H.; Moehler, M. Int. J. Cancer 2010, 127, 1197.
12. Hui, E. P.; Lui, V. W.; Wong, C. S.; Ma, B. B.; Lau, C. P.; Cheung, C. S.; Ho, K.;
Cheng, S. H.; Ng, M. H.; Chan, A. T. Invest. New Drugs 2010, doi: 10.1007/
s10637-010-9451-1
13. Morabito, A.; De Maio, E.; Di Maio, M.; Normanno, N.; Perrone, F. Oncologist
2006, 11, 753.
In summary, we report herein the design and synthesis of some
novel 5-[1-(3-(dimethylamino)propyl)-5-halogenated-2-oxoindo-
lin-(3Z)-ylidenemethyl]-2,4-dimethyl-1H-pyrrole-3-carboxamides
based on the structural features of Sunitnib and TMP-20. The new-
ly synthesized compounds were evaluated for their in vitro activity
against five human cancer cell lines and VEGF/bFGF-stimulated
HUVECs. Our results revealed that all of the target compounds
show potent antitumor activity, and the most active compound
1h is 2.1–4.6-fold more potent than Sunitinib against the tested
five cancer cell lines. In addition, 1a–p have higher selectivity on
VEGF-stimulated HUVEC other than bFGF-stimulated HUVEC.
14. Wang, L. L.; Li, J. J.; Zheng, Z. B.; Liu, H. Y.; Du, G. J.; Li, S. Eur. J. Pharmacol. 2004,
502, 1.
15. Lu, H. Y.; Lin, C.; Zheng, Z.; Li, S.; Guo, S.; Zhang, X.; Fu, M.; Liang, X.; Wu, M. J.
Pharmacol. Sci. 2005, 97, 533.
References and notes
16. Lu, H. Y.; Lin, C.; Li, S.; Zheng, Z. B.; Zhang, X. Y.; Zhang, L. S.; Xu, G. Z.; Guo, S. X.;
Wu, M.; Fu, M. Chin. J. Pharmacol. Toxicol. 2003, 17, 401.
17. David, S. S. J. Chem. Edu. 1993, 70, 332.
18. To a stirring solution of 9a (4.95 g, 30 mmol) in methanol (80 mL) was added
dropwise 85% hydrazine hydrate (3.53 mL, 60 mmol) over a period of 30 min at
1. Naparat, K.; Chantana, B.; Kingkan, S.; Maleeruk, U.; Satoshi, T.; Hiroaki, S.;
Ikuo, S.; Isabelle, A.; David, S. G.; Opa, V. Bioorg. Med. Chem. Lett. 2009, 19, 745.
2. Yisheng, L.; Lin, M.; Wenxing, H.; Xing, Y.; Yihua, Z.; Hui, J.; Jide, T. Bioorg. Med.
Chem. Lett. 2010, 20, 7349.

K. Lv et al. / Bioorg. Med. Chem. Lett. 21 (2011) 3062–3065
3065
room temperature. The reaction mixture was heated to refluxing and stirred
for 1 h, and then cooled to room temperature and filtrated. The solid obtained
was washed with methanol and dried in vacuo to give 10a (4.85 g, 90.2%) as a
2.07 (m, 2H), 2.49 (s, 6H), 2.70 (s, 3H), 2.71 (s, 3H), 2.81 (s, 3H), 2.82 (s, 3H),
3.10–3.12 (m, 2H), 3.23–3.25 (m, 2H), 3.61–3.63 (m, 2H), 3.93 (t, 2H, J = 7 Hz),
7.21–7.26 (m, 2H), 7.84 (s, 1H), 8.00–8.03 (m, 1H), 8.07–8.09 (m, 1H), 10.67 (br
s, 2H), 13.57 (s, 1H). FAB-MS: m/z 472.2 (M+H)+. Compound 1g, mp: 70–71 °C.
1H NMR (400 Hz, CD3OD) d ppm: 1.37 (t, 6H, J = 7 Hz), 2.13–2.16 (m, 2H), 2.47
(s, 3H), 2.51 (s, 3H), 2.87 (s, 6H), 3.20 (t, 2H, J = 8 Hz), 3.28–3.39 (m, 6H), 3.73 (t,
2H, J = 6 Hz), 3.96 (t, 2H, J = 6 Hz), 6.91–6.96 (m, 1H), 7.03–7.08 (m, 1H), 7.47–
7.49 (m, 1H), 7.59 (s, 1H), 13.61 (s, 1H). FAB-MS: m/z 484.1 (M+H)+. Compound
1h, mp: 124–126 °C. 1H NMR (400 Hz, DMSO ꢁ d6 + D2O) d ppm: 1.06 (t, 6H,
J = 7 Hz), 2.23 (s, 6H), 1.86–1.91 (m, 2H), 2.33 (t, 2H, J = 7 Hz), 2.51 (s, 3H),
2.58–2.64 (m, 7H), 2.70 (t, 2H, J = 6 Hz), 3.50 (q, 2H, J = 5 Hz), 3.88 (t, 2H,
J = 7 Hz), 6.59 (br s, 1H), 6.88 (d, 1H, J = 8 Hz), 7.14 (dd, 1H, J1 = 2 Hz, J2 = 8 Hz),
7.35 (s, 1H), 7.43 (d, 1H, J = 2 Hz), 13.55 (s, 1H). FAB-MS: m/z 500.1 (M+H)+. 1i,
mp: 138–139 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm: 1.80–1.89 (m, 4H),
2.00–2.08 (m, 2H), 2.29 (s, 3H), 2.32 (s, 3H), 2.72 (s, 3H), 2.73 (s, 3H), 3.08–3.21
(m, 2H), 3.21–3.24 (m, 2H), 3.44–3.47 (m, 2H), 3.93 (t, 2H, J = 7 Hz), 7.02–7.07
(m, 1H), 7.16–7.20 (m, 1H), 7.77 (s, 1H), 7.84–7.87 (m, 1H), 10.30 (br s, 1H),
13.49 (s, 1H). EI-MS: m/z 438.2 M+. Compound 1j, mp: 136–138 °C. 1H NMR
(400 Hz, DMSO ꢁ d6) d ppm: 1.86–1.93 (m, 4H), 2.02–2.08 (m, 2H), 2.30 (s, 3H),
2.32 (s, 3H), 2.72 (s, 3H), 2.73 (s, 3H), 3.08–3.13 (m, 2H), 3.19-3.22 (m, 2H),
3.43–3.46 (m, 2H), 3.93 (t, 2H, J = 7 Hz), 7.19–7.26 (m, 2H), 7.82 (s, 1H), 8.06 (d,
1H, J = 2 Hz), 10.28 (br s, 1H), 13.44 (s, 1H). EI-MS: m/z 454.1 M+. Compound
1k, dec.: 263 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm: 1.48–1.53 (m, 6H), 2.01–
2.06 (m, 2H), 2.27 (s, 3H), 2.30 (s, 3H), 2.72 (s, 3H), 2.73 (s, 3H), 3.09–3.14 (m,
2H), 3.43–3.52 (m, 4H), 3.93 (t, 2H, J = 7 Hz), 7.01–7.02 (m, 1H), 7.16–7.19 (m,
1H), 7.77 (s, 1H), 7.83–7.86 (m, 1H), 10.24 (br s, 1H), 13.51 (s, 1H). EI-MS: m/z
452.1 M+. Compound 1l, dec.: 256 °C. Yield: 39.3%. 1H NMR (400 Hz,
DMSO ꢁ d6) d ppm: 1.48–1.61 (m, 6H), 1.99–2.07 (m, 2H), 2.26–2.32 (m, 6H),
2.73 (s, 3H), 2.74 (s, 3H),3.11–3.13 (m, 2H), 3.41–3.53 (m, 4H), 3.93 (t, 2H,
J = 7 Hz), 7.18–7.26 (m, 2H), 7.82 (s, 1H), 8.07 (d, 1H, J = 2 Hz), 10.01 (br s, 1H),
13.47 (s, 1H). EI-MS: m/z 468.1 M+. Compound 1m, mp: 214–216 °C. 1H NMR
(400 Hz, DMSO ꢁ d6) d ppm: 2.02–2.10 (m, 2H), 2.32–2.35 (m, 6H), 2.70 (s, 3H),
2.72 (s, 3H), 2.76–2.78 (m, 3H), 2.99–3.01 (m, 2H), 3.09–3.14 (m, 2H), 3.37–
3.46 (m, 6H), 3.93 (t, 2H, J = 7 Hz), 7.02–7.07 (m, 1H), 7.19–7.22 (m, 1H), 7.79
(s, 1H), 7.85–7.88 (m, 1H), 10.82 (br s, 1H), 11.60 (br s, 1H), 13.57 (s, 1H). FAB-
MS: m/z 468.2 (M+H)+. 1n, dec.: 232 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm:
2.02–2.10 (m, 2H), 2.32–2.35 (m, 6H), 2.72 (s, 6H), 2.75–2.77 (m, 3H), 2.95–
3.06 (m, 2H), 3.08–3.13 (m, 2H), 3.37–3.39 (m, 6H), 3.93 (t, 2H, J = 7 Hz), 7.23–
7.26 (m, 2H), 7.85 (s, 1H), 8.09 (d, 1H, J = 2 Hz), 10.59 (br s, 1H), 11.38 (br s, 1H),
13.55 (s, 1H). FAB-MS: m/z 484.1 (M+H)+. 1o, mp: 199–201 °C. 1H NMR
(400 Hz, DMSO ꢁ d6) d ppm: 1.20 (t, 3H, J = 7 Hz), 2.03–2.09 (m, 2H), 2.32–2.35
(m, 6H), 2.71 (s, 3H), 2.73 (s, 3H), 2.92-2.95 (m, 2H), 3.10–3.15 (m, 4H), 3.41–
3.56 (m, 6H), 3.93 (t, 2H, J = 7 Hz), 7.03–7.08 (m, 1H), 7.18–7.21 (m, 1H), 7.79
(s, 1H), 7.86–7.88 (m, 1H), 10.47 (br s, 1H), 11.27 (br s, 1H), 13.58 (s, 1H). FAB-
MS: m/z 482.2 (M+H)+. 1p, dec.: 222 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm:
1.27 (t, 3H, J = 7 Hz), 2.02–2.07 (m, 2H), 2.33 (s, 3H), 2.35 (s, 3H), 2.70 (s, 3H),
2.72 (s, 3H), 2.92–2.95 (m, 2H), 3.09–3.13 (m, 4H), 3.40–3.48 (m, 2H), 3.82–
3.88 (m, 4H), 3.95 (t, 2H, J = 7 Hz), 7.23–7.25 (m, 2H), 7.84 (s, 1H), 8.09 (d, 1H,
J = 2 Hz), 10.66 (br s, 1H), 11.45 (br s, 1H), 13.54 (s, 1H). FAB-MS: m/z 498.2
(M+H)+.
yellow solid, mp: 183–185 °C (183–185 °C20).
A mixture of 10a (3.58 g,
20 mmol) and sodium ethoxide (6.80 g, 100 mmol) in absolute ethanol
(100 mL) was heated to refluxing and stirred for 5 h, and then cooled to
room temperature. To the mixture was added slowly ice-water (100 mL),
adjusted to pH
1 with 4 N HCl and filtrated. The solid obtained was
recrystallized from water to afford 11a (2.43 g, 80.4%) as an off-white solid,
mp: 135–137 °C (135–137 °C20). A suspension of KF (23.24 g, 400 mmol) and
Al2O3 (40.80 g, 400 mmol) in water was stirred for 0.5 h at room temperature,
and then concentrated under reduced pressure, dried in vacuo to prepare KF-
Al2O3(64.04 g, 100%).
A mixture of 11a (6.04 g, 40 mmol), 1-chloro-3-
dimethylaminopropane hydrochloride (5.53 g, 35 mmol) and KF-Al2O3
(19.21 g, 120 mmol) in anhydrous acetonitrile (150 mL) was heated to
refluxing and stirred for 10 h, and then cooled to room temperature and
filtered. The filtrate was concentrated under reduced pressure. The crude
product was purified by column chromatography (silica gel) eluted with
petroleum ether and ethyl acetate (v:v = 1:1) to afford 12a (4.73 g, 50.1%) as a
brown oil. 1H NMR (400 MHz, CDCl3) d ppm: 1.85–1.80 (m, 2H), 2.22 (s, 6H),
2.33 (t, 2H, J = 7 Hz), 3.52 (s, 2H), 3.76 (t, 2H, J = 7 Hz), 6.84–6.81 (m, 1H), 7.01–
6.94 (m, 2H). A mixture of 12a (0.73 g, 3.1 mmol), 8a (0.58 g, 3 mmol) and
pyrrolidine (0.3 mL) in methanol (15 mL) was heated to refluxing and stirred
for 2 h, and then concentrated under reduced pressure. The residue was
purified by column chromatography (silica gel) eluted with methanol and
dichloromethane (v:v = 1:40) to yield the free base of 1a, which was dissolved
in absolute diethyl ether, and then pumped dried hydrochloride gas at 0–5 °C
for 30 min. The reaction mixture was allowed to stir for another 30 min at
room temperature, the resulting solid was collected by suction, and dried in
vacuo to give the title compound 1a (0.62 g, 46.3%, for two steps) as a yellow
solid, mp: 120–122 °C. 1H NMR (400 Hz, DMSO ꢁ d6 + D2O) d ppm: 2.02–2.05
(m, 2H), 2.27 (s, 3H), 2.30 (s, 3H), 2.77 (s, 6H),2.92–2.99 (m, 6H), 3.11–3.16 (m,
2H), 3.91 (t, 2H, J = 7 Hz), 7.05–7.14 (m, 2H), 7.73–7.77 (m, 2H), 13.46 (s, 1H).
FAB-MS: m/z 413.2 (M+H)+
.
The other target compounds 1b–1p (yields: 35.1–64.2%) were obtained as
yellow solids in a similar manner as for the preparation of 1a. Compound 1b,
mp: 112–114 °C. 1H NMR (400 Hz, DMSO ꢁ d6 + D2O) d ppm: 2.02–2.06 (m,
2H), 2.28 (s, 3H), 2.30 (s, 3H), 2.77 (s, 6H), 2.93–3.11 (m, 6H), 3.13-3.15 (m, 2H),
3.92 (t, 2H, J = 7 Hz), 7.19–7.24 (m, 2H), 7.77 (s, 1H), 7.99 (d, 1H, J = 2 Hz), 13.43
(s, 1H). FAB-MS: m/z 429.1 (M+H)+. Compound 1c, mp: 178–180 °C. 1H NMR
(400 Hz, DMSO ꢁ d6 + D2O) d ppm: 1.05 (t, 3H, J = 7 Hz), 1.22 (t, 3H, J = 7 Hz),
2.02–2.10 (m, 2H), 2.22 (s, 3H), 2.31 (s, 3H), 2.82 (s, 6H), 3.15 (t, 2H, J = 8 Hz),
3.30–3.32 (m, 2H), 3.53–3.55 (m, 2H), 3.84 (t, 2H, J = 7 Hz), 7.01–7.03 (m, 2H),
7.42–7.45 (m, 2H), 13.09 (s, 1H). FAB-MS: m/z 441.2 (M+H)+. Compound 1d,
mp: 96–98 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm: 1.01–1.12 (m, 6H), 2.03–
2.07 (m, 2H), 2.26 (s, 3H), 2.28 (s, 3H), 2.71 (s, 3H), 2.76 (s, 3H), 3.08–3.13 (m,
2H), 3.26–3.52 (m, 4H), 3.93 (t, 2H, J = 7 Hz), 7.19–7.23 (m, 2H), 7.81 (s, 1H),
8.05 (s, 1H), 10.53 (brs, 1H), 13.45 (s, 1H). FAB-MS: m/z 458.1 (M+H)+.
Compound 1e, mp: 90–92 °C. 1H NMR (400 Hz, DMSO ꢁ d6 + D2O) d ppm: 2.04–
2.08 (m, 2H), 2.43 (s, 3H), 2.48 (s, 3H), 2.80 (s, 6H), 2.90 (s, 6H), 3.13–3.17 (m,
2H), 3.30 (t, 2H, J = 6 Hz), 3.66 (t, 2H, J = 6 Hz), 3.91 (t, 2H, J = 7 Hz), 7.06–7.11
(m, 2H), 7.63–7.65 (m, 2H), 13.40 (s, 1H). FAB-MS: m/z 456.2 (M+H)+.
Compound 1f, mp: 200–202 °C. 1H NMR (400 Hz, DMSO ꢁ d6) d ppm: 2.04–
19. Green, L. M.; Reade, J. L.; Ware, C. F. J. Immunol. Methods 1984, 70, 257.
20. Lv, K.; Du, Y. M.; Zhao, D. M.; Zheng, Z. B.; Li, S. Chin. J. Med. Chem. 2009, 19, 116.