Design, Synthesis, and In Vitro Anti-mycobacterial Activities of Propylene-Tethered Gatifloxacin-Isatin Hybrids

Article abstract of DOI:10.1002/jhet.3227

A series of propylene-tethered mono-/bis-isatin-gatifloxacin hybrids 3a–f and 4a–f were designed, synthesized, and evaluated for their in vitro anti-mycobacterial activities against Mycobacterium tuberculosis (MTB) H37Rv and multidrug-resistant tuberculosis (MDR-TB) as well as cytotoxicity against VERO cell line. The results indicated that all hybrids exhibited promising anti-mycobacterial activities against MTB H37Rv and MDR-TB with MIC ranging from 0.25 to 16?μg/mL. In particular, the mono-isatin-gatifloxacin hybrid 3e (MIC: 0.25 and 0.25?μg/mL) was found to be most active against MTB H₃₇Rv and MDR-TB strains, which was twofold more active than the parent gatifloxacin (MIC: 0.5?μg/mL) and comparable with rifampicin (RIF) (MIC: 0.25?μg/mL) against MTB H₃₇Rv, and 4- > 512 times more potent than the three references gatifloxacin (MIC: 1.0?μg/mL), RIF (MIC: 64?μg/mL), and isoniazid (>128?μg/mL) against MDR-TB, could act as a starting point for further optimization.

Full text of DOI:10.1002/jhet.3227

Month 2018
Design, Synthesis, and In Vitro Anti-mycobacterial Activities of
Propylene-Tethered Gatifloxacin-Isatin Hybrids
a
a
a
b
b
Hao-Di Wang, Yi-Lei Fan, *
Jing Zhou, Yan Xu, and Jianguo Guan
a
Key Laboratory of Drug Prevention and Control Technology of Zhejiang Province, Zhejiang Police College, Hangzhou,
Zhejiang, People’s Republic of China
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of
b
Technology, Wuhan, Hubei, People’s Republic of China
*
E-mail: fanyilei@zjjcxy.cn
Received March 13, 2018
DOI 10.1002/jhet.3227
Published online 00 Month 2018 in Wiley Online Library (wileyonlinelibrary.com).
A series of propylene-tethered mono-/bis-isatin-gatifloxacin hybrids 3a–f and 4a–f were designed, synthe-
sized, and evaluated for their in vitro anti-mycobacterial activities against Mycobacterium tuberculosis
MTB) H37Rv and multidrug-resistant tuberculosis (MDR-TB) as well as cytotoxicity against VERO cell
(
line. The results indicated that all hybrids exhibited promising anti-mycobacterial activities against
MTB H37Rv and MDR-TB with MIC ranging from 0.25 to 16 μg/mL. In particular, the mono-isatin-
gatifloxacin hybrid 3e (MIC: 0.25 and 0.25 μg/mL) was found to be most active against MTB H37Rv and
MDR-TB strains, which was twofold more active than the parent gatifloxacin (MIC: 0.5 μg/mL) and com-
parable with rifampicin (RIF) (MIC: 0.25 μg/mL) against MTB H37Rv, and 4- > 512 times more potent than
the three references gatifloxacin (MIC: 1.0 μg/mL), RIF (MIC: 64 μg/mL), and isoniazid (>128 μg/mL)
against MDR-TB, could act as a starting point for further optimization.
J. Heterocyclic Chem., 00, 00 (2018).
INTRODUCTION
Fluoroquinolones are a family of synthetic broad
spectrum antibiotics with extensive indications for
infections including upper and lower respiratory
infections, gastrointestinal infections, gynecologic
infections, sexually transmitted diseases, prostatitis, and
some skin, bone, and soft tissue infections, and their
value and role in the treatment of bacterial infections
continue to expand [6,7]. Fluoroquinolones also exhibit
promising anti-TB activities; although they are presently
recommended as second-line anti-TB agents used to treat
primarily in cases involving resistance or intolerance to
first-line anti-TB therapy by WHO, these drugs are
potential first-line agents [7]. Moreover, MTB isolates
that are resistant to both INH and RIF are still
susceptible to fluoroquinolones generally. The recent
research demonstrated that the lipophilicity of the
fluoroquinolones plays an important role in the
penetration of these compounds into bacterial cells,
suggesting that increasing the lipophilic character at C-7
position may favor the anti-TB activity [8–11]. Isatin
(1H-indole-2,3-dione, Fig. 1) derivatives endow with a
broad range of biological properties such as anti-TB
activity [12,13]. Therefore, incorporation of isatin into
fluoroquinolones may lead to more active candidates.
Tuberculosis (TB), which is caused mainly by
Mycobacterium tuberculosis (MTB), affects dominantly
the lungs (pulmonary TB) apart from other vital organs,
has been a scourge of humanity for thousands of years
[
1,2]. According to the global tuberculosis report 2017 by
World Health Organization (WHO), TB is the ninth
leading cause of death throughout the world and the
leading cause from a single infectious agent [3]. The
WHO has estimated that around 10.4 million newly TB
infected cases occurred in the year 2016 and, among
them, led to 1.67 million deaths [3].
The first-line drugs such as isoniazid (INH), rifampicin
RIF), pyrazinamide, and ethambutol play a pivotal role
(
for the treatment of drug-susceptible MTB infected
patients [4,5]. However, the evolution of MTB new
virulent forms such as drug-resistant TB (DR-TB),
multidrug-resistant TB (MDR-TB) and extremely drug-
resistant TB (XDR-TB) make the first-lineanti-TB drugs
more and more ineffective. Therefore, there is an urgent
need to develop new anti-TB agents active against
various virulent forms of MTB with low toxicity, short
therapy duration, and new action mechanism.
©
2018 Wiley Periodicals, Inc.

H.-D. Wang, Y.-L. Fan, J. Zhou, Y. Xu, and J. Guan
Vol 000
Figure 1. Chemical structures of isatin and isatin-gatifloxacin hybrid 1.
Figure 2. Illustration of design strategy. [Color figure can be viewed at wileyonlinelibrary.com]
Scheme 1. Synthetic route for mono-/bis-isatin-gatifloxacin hybrids 3a–f and 4a–f.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Design, Synthesis and In Vitro Anti-mycobacterial Activities of Propylene-
Tethered Gatifloxacin-Isatin Hybrids
Various fluoroquinolones-isatin hybrids tethered
through different linkers such as methylene, ethylene,
acetyl, carbohydrazide, and 1,2,3-triazole have been
synthesized and screened for their anti-TB activities by
our group, and some of them demonstrated considerable
activity [14–21]. In particular, gatifloxacin-isatin hybrid 1
RESULTS AND DISCUSSION
The synthetic pathways for propylene-tethered
mono-/bis-isatin-gatifloxacin hybrids 3a–f and 4a–f are
outlined in Scheme 1. Alkylation of C-5 substituted
isatins 1a–c was performed with 1,3-dibromopropane in
presence of K CO to provide N-(3-bromopropyl) isatins
(
MIC: 0.10 and 0.25 μg/mL) were fourfold to eightfold
more active in vitro than the parent gatifloxacin (MIC:
.78 and 1.0 μg/mL) against MTB H37Rv and MDR-TB
2
3
2a–c, which were then incorporated into gatifloxacin core
to afford the desired mono-isatin-gatifloxacin 3a–c
and bis-isatin-gatifloxacin hybrids 4a–c. Subsequently,
condensation of hybrids 3a–c or 4a–c with
methylhydroxylamine hydrochloride in the presence of
sodium bicarbonate provided other conjugates 3d–f and
4d–f.
0
strains, represents a new class of lead warrant further
investigation [15].
Based on the aforementioned research results and as a
continuous research program to optimize the linker
between fluoroquinolones and isatin, a series of novel
propylene-tethered mono-/bis-isatin-gatifloxacin hybrids
were designed, synthesized, and assessed for their
in vitro anti-mycobacterial activities against MTB H37Rv
and MDR-TB as well as cytotoxicity against VERO cell
line in this study. The design strategy is illustrated in
Figure 2.
All propylene-tethered mono-/bis-isatin-gatifloxacin
3a–f and 4a–f were assessed for their in vitro anti-
mycobacterial activity against MTB H Rv and MDR-TB
37
as well as cytotoxicity against VERO cell line [15]. From
Table 1, it can be concluded that all hybrids exhibited
considerable activity against the tested two strains with
Table 1
Structures, anti-mycobacterial activity, and cytotoxicity of hybrids 3a–f and 4a–f.
MIC (μg/mL)
a
Compd.
R
1
R
2
MTB H37Rv
MDR-TB
CC50 (μg/mL)
3
3
3
3
3
3
4
4
4
4
4
4
a
b
c
d
e
f
a
b
c
d
e
f
H
F
Br
H
F
Br
H
F
Br
H
F
O
O
O
NOMe
NOMe
NOMe
O
O
O
2
0.5
1
2
0.5
2
256
64
128
128
32
128
512
64
128
128
32
1
2
0.25
0.5
16
8
16
16
8
0.25
0.5
16
16
16
8
8
8
NOMe
NOMe
NOMe
Br
8
256
128
512
1024
Gatifloxacin
INH
RIF
0.5
0.06
0.25
1
>128
64
INH, isoniazid; MDR-TB, multidrug-resistant tuberculosis; MTB, Mycobacterium tuberculosis; RIF, rifampicin.
a
CC50: The 50% cytotoxic concentration in a mammalian VERO cell line.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

H.-D. Wang, Y.-L. Fan, J. Zhou, Y. Xu, and J. Guan
Vol 000
MIC in a range of 0.25 to 16 μg/mL against MTB H Rv
(3 mmol) in DMF (50 mL), K CO3 (20 mmol) was
37
2
and MDR-TB. The structure–activity relationship
revealed that all mono-isatin-gatifloxacin hybrids were
more potent than the corresponding bis-isatin-gatifloxacin
analogs, which was in accordance with the previous
study that carboxylic acid at C-3 position is essential for
gyrase binding and bacterial membrane transport [6];
substituents at C-3 and C-5 positions of isatin moiety
have significant influence on the anti-mycobacterial
activity, and introduction of methoxyimino at C-3
position as well as electron-withdrawing -F at C-5
position of isatin moiety could boost up the activity. In
particular, the most potent hybrid 3e with MIC of 0.25
and 0.25 μg/mL against MTB H Rv and MDR-TB
added. The mixture was stirred at room temperature for
3 days. After filtration, the filtrate was concentrated under
reduced pressure. The residue was purified by reverse
phase column with formic acid as additive to provide the
desired targets 3a–c and bis-isatin-GTFX hybrids 4a–c.
1-Cyclopropyl-7-(4-(3-(2,3-dioxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-6-fluoro-8-methoxy-4-oxo-1,4-
dihydroquinoline-3-carboxylic acid formic acid salt (3a).
Yellow solid, yield: 38%. H NMR (400 MHz, DMSO-d6)
δ 0.95–1.09 (7H, m, 2 × cyclopropyl–CH and CH ),
2
3
1
.99–2.05 (2H, m, –CH –), 2.96–3.31 (7H, m,
2
piperazine–7H), 3.77 (3H, s, OCH ), 3.87 (2H, t, –CH –),
3
2
4
.00–4.02 (1H, m, cyclopropyl–CH), 4.24 (2H, t, –CH –),
2
3
7
7
.09 (1H, t, Ar–H), 7.32 (1H, d, Ar–H), 7.46 (1H, d,
was twofold more active than the parent gatifloxacin
MIC: 0.5 μg/mL) and comparable with RIF (MIC:
.25 μg/mL) against MTB H Rv, and 4- > 512 times
Ar–H), 7.60–7.63 (2H, m, Ar–H), 8.31 (1H, s, CHO),
(
+
8
.47 (1H, s, C2–H). ESI-MS m/z: 563 [M + H] .
0
3
7
Elemental Anal. Calcd (%) for C H FN O : C, 61.18;
more potent than the three references gatifloxacin (MIC:
31 33
4 8
H, 5.47; N, 9.21; found: C, 60.94; H, 5.21; N, 9.07.
1.0 μg/mL), RIF (MIC: 64 μg/mL), and INH
7
-(4-(3-(5-Bromo-2,3-dioxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-
,4-dihydroquinoline-3-carboxylic acid formic acid salt (3b).
(
>128 μg/mL) against MDR-TB.
The propylene-tethered isatin-CPFX hybrids 3a–f
1
and 4a–f were subsequently examined for toxicity (CC )
50
Yellow solid, yield: 31%. H NMR (400 MHz, DMSO-d ) δ
6
in a mammalian VERO cell line [14]. After 72 h
of exposure, viability was assessed on the basis of
cellular conversion of MTT (3-(4,5-dimethylthiazol-2-yl)-
0
.84–0.96 (4H, m, 2 × cyclopropyl–CH ), 1.08 (3H, d,
2
CH ), 1.98–2.05 (2H, m, –CH –), 2.94–3.31 (7H, m,
3
2
piperazine–7H), 3.79 (3H, s, OCH ), 3.88 (2H, t, –CH –),
3
2
2,5-diphenyltetrazolium bromide) into
a
formazan
4
.00–4.02 (1H, m, cyclopropyl–CH), 4.20 (2H, t, –CH –),
2
product, and the results are reported in Table 1. All
7
.24 (1H, d, Ar–H), 7.58–7.62 (2H, m, Ar–H), 7.88
hybrids (CC : 32–512 μg/mL) showed acceptable
50
(
1H, s, Ar–H), 8.26 (1H, s, CHO), 8.36 (1H, s, C2–H).
cytotoxicity, and the structure–cytotoxicity relationship
revealed that hybrids with -F at C-5 position showed
higher cytotoxicity in VERO cell line. The cytotoxicity of
the most potency 4e (CC : 32 μg/mL) displayed
+
+
ESI-MS m/z: 641 [M + H] , 643 [M + 2 + H] .
Elemental Anal. Calcd (%) for C H FBrN O : C,
31
32
4 8
5
4.16; H, 4.69; N, 8.15; found: C, 53.89; H, 4.47; N, 8.01.
5
0
7
-(4-(3-(5-Fluoro-2,3-dioxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-
,4-dihydroquinoline-3-carboxylic acid formic acid salt (3c).
acceptable cytotoxicity.
1
Yellow solid, yield: 27%. H NMR (400 MHz, DMSO-d ) δ
6
CONCLUSION
0
2
3
.93–1.06 (7H, m, 2 × cyclopropyl–CH and CH ), 1.99–
2 3
.04 (2H, m, –CH –), 2.93–3.32 (7H, m, piperazine–7H),
2
In summary, a series of novel propylene-tethered isatin-
gatifloxacin hybrids were synthesized and evaluated for
their in vitro anti-mycobacterial activity against MTB
.79 (3H, s, OCH ), 3.89 (2H, t, –CH –), 3.99–4.00 (1H,
3
2
m, cyclopropyl–CH), 4.19 (2H, t, –CH –), 7.30–7.32
2
(
2H, m, Ar–H), 7.57–7.64 (2H, m, Ar–H), 8.28 (1H, s,
H Rv and MDR-TB as well as cytotoxicity. All hybrids
+
37
CHO), 8.40 (1H, s, C2–H). ESI-MS m/z: 581 [M + H] .
Elemental Anal. Calcd (%) for C H F N O : C, 59.46;
exhibited considerable inhibitory activity against the
tested strains, and the most active conjugate 3e with
acceptable cytotoxicity was more potent than the parent
GTFX and RIF against MTB H Rv and MDR-TB,
31 32 2 4 8
H, 5.15; N, 8.94; found: C, 59.29; H, 5.02; N, 8.77.
3
-(2,3-Dioxoindolin-1-yl) propyl 1-cyclopropyl-7-(4-(3-(2,3-
3
7
dioxoindolin-1-yl)propyl)-3-methylpiperazin-1-yl)-6-fluoro-8-
warrant further investigations.
methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate (4a).
Yellow solid, yield: 14%. H NMR (400 MHz, DMSO-d6)
δ 0.96–1.08 (7H, m, 2 × cyclopropyl–CH and CH ),
2
3
EXPERIMENTAL SECTION
2.02–2.12 (4H, m, 2 × –CH
–), 2.99–3.64 (9H, m,
2
piperazine–7H and –CH –), 3.76–3.88 (7H, m, OCH3
2
and 2 × –CH –), 4.00–4.02 (1H, m, cyclopropyl–CH),
Synthesis. General procedure for the preparation of 3a–c
2
and 4a–c.
N-(3-bromopropyl) isatins 2a–c were
4.24 (2H, t, –CH –), 7.07–7.10 (1H, m, Ar–H), 7.17 (1H,
2
obtained via literature reported method [14]. To a mixture
of N-(3-bromopropyl) isatins 2a–c (5 mmol) and GTFX
t, Ar–H), 7.28–7.33 (2H, m, Ar–H), 7.46 (1H, d, Ar–H),
7.60–7.73 (4H, m, Ar–H), 8.48 (1H, s, C2–H). ESI-MS
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2018
Design, Synthesis and In Vitro Anti-mycobacterial Activities of Propylene-
Tethered Gatifloxacin-Isatin Hybrids
+
+
m/z: 772 [M + Na] . Elemental Anal. Calcd (%) for
ESI-MS m/z: 592 [M + H] . Elemental Anal. Calcd (%)
C H FN O : C, 65.68; H, 5.38; N, 9.34; found: C,
for C H FN O : C, 60.27; H, 5.69; N, 10.98; found: C,
4
1
40
5
8
32 36
5 8
6
5.47; H, 5.32; N, 9.06.
60.09; H, 5.41; N, 10.74.
7-(4-(3-(5-Bromo-2,3-dioxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-
3-(5-Bromo-2,3-dioxoindolin-1-yl) propyl 7-(4-(3-(5-bromo-
2
,3-dioxoindolin-1-yl)propyl)-3-methylpiperazin-1-yl)-1-
1
,4-dihydroquinoline-3-carboxylic acid formic acid salt (3e).
cyclopropyl-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-
carboxylate (4b). Yellow solid, yield: 11%. H NMR (400
Yellow solid, yield: 37%. H NMR (400 MHz, DMSO-d ) δ
6
MHz, DMSO-d ) δ 0.92–1.06 (7H, m, 2 × cyclopropyl–
0.84–0.96 (4H, m, 2 × cyclopropyl–CH ), 1.06 (3H, d,
6
2
CH and CH ), 1.77–1.80 (2H, m, –CH –), 1.99–2.01
CH ), 1.98–2.04 (2H, m, –CH –), 2.90–3.30 (7H, m,
2
3
2
3
2
(
2H, m, –CH –), 2.27–2.30 (2H, m, –CH –), 2.91–3.30
piperazine–7H), 3.80 (3H, s, OCH ), 3.87–3.90 (2H, m,
2
2
3
(
7H, m, piperazine–7H), 3.71–3.90 (7H, m, OCH and
–CH –), 3.98–4.00 (1H, m, cyclopropyl–CH), 4.17–4.20
3
2
2
4
7
× –CH –), 4.00–4.01 (1H, m, cyclopropyl–CH),
(5H, m, NOMe and –CH –), 7.26 (1H, d, Ar–H),
2
2
.18–4.20 (2H, m, –CH –), 7.20–7.27 (2H, m, Ar–H),
7.59–7.64 (2H, m, Ar–H), 7.88 (1H, s, Ar–H), 8.24 (1H,
s, CHO), 8.39 (1H, s, C2–H). ESI-MS m/z: 670
2
.58–7.61 (2H, m, Ar–H), 7.68 (1H, d, Ar–H), 7.87 (1H,
+
+
s, Ar–H), 7.99 (1H, s, Ar–H), 8.36 (1H, s, C2–H).
ESI-MS m/z: 906 [M + H] , 908 [M + 2 + H] , 910
[M + H] , 672 [M + 2 + H] . Elemental Anal. Calcd
+
+
(%) for C H FBrN O : C, 53.64; H, 4.92; N, 9.77;
3
2
35
5 8
+
[
M + 4 + H] . Elemental Anal. Calcd (%) for
found: C, 53.59; H, 4.77; N, 9.54.
1
-Cyclopropyl-6-fluoro-7-(4-(3-(5-fluoro-3-(methoxyimino)-
-oxoindolin-1-yl)propyl)-3-methylpiperazin-1-yl)-8-methoxy-4-
oxo-1,4-dihydroquinoline-3-carboxylic acid formic acid salt
C H FBr N O : C, 54.26; H, 4.22; N, 7.72; found: C,
4
1
38
2 5 8
2
53.93; H, 4.01; N, 7.52.
3
-(5-Fluoro-2,3-dioxoindolin-1-yl) propyl 1-cyclopropyl-6-
1
(
3f).
Yellow solid, yield: 42%. H NMR (400 MHz,
fluoro-7-(4-(3-(5-fluoro-2,3-dioxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-8-methoxy-4-oxo-1,4-dihydroquinoline-
DMSO-d ) δ 0.94–1.08 (4H, m, 2 × cyclopropyl–CH ),
6
2
3
(
2
1
2
-carboxylate (4c).
Yellow solid, yield: 17%. H NMR
400 MHz, DMSO-d6) 0.93–1.06 (7H, m,
× cyclopropyl–CH and CH ), 1.78–1.80 (2H, m, –CH –),
1.14 (3H, d, CH
3
), 1.97–2.03 (2H, m, –CH
2
–), 3.00–3.34
), 3.88 (2H, t,
δ
(7H, m, piperazine–7H), 3.80 (3H, s, OCH
–CH –), 3.90–3.99 (1H, m, cyclopropyl–CH), 4.11–4.20
(5H, m, NOMe and –CH –), 7.21–7.31 (2H, m, Ar–H),
3
2
3
2
2
.99–2.04 (2H, m, –CH –), 2.37–2.40 (2H, m, –CH –),
.85–3.27 (7H, m, piperazine–7H), 3.74–3.89 (7H, m,
2
2
2
7.76–7.63 (2H, m, Ar–H), 8.40 (1H, s, C2–H). ESI-MS
m/z: 610 [M + H] . Elemental Anal. Calcd (%) for
+
OCH and 2 × –CH –), 4.00–4.02 (1H, m, cyclopropyl–
3
2
CH), 4.17–4.20 (2H, m, –CH –), 7.24–7.44 (4H, m, Ar–H),
C
32
H
F
35
N
2
O
5
: C, 58.62; H, 5.38; N, 10.68; found: C,
8
2
7
8
.56–7.62 (2H, m, Ar–H), 7.69–7.71 (1H, m, Ar–H),
.40 (1H, s, C2–H). ESI-MS m/z: 808 [M + Na] .
58.39; H, 5.10; N, 10.51.
+
3
-(3-(Methoxyimino)-2-oxoindolin-1-yl) propyl 1-cyclopropyl-
6
-fluoro-8-methoxy-7-(4-(3-(3-(methoxyimino)-2-oxoindolin-1-
Elemental Anal. Calcd (%) for C H F N O : C, 62.67;
H, 4.87; N, 8.91; found: C, 62.31; H, 4.56; N, 8.63.
4
1 38 3 5 8
yl)propyl)-3-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-
carboxylate (4d). Yellow solid, yield: 67%. H NMR (400
The general procedure for preparing targets 3d–f and 4d–
f. To a solution of methylhydroxylamine hydrochloride
MHz, DMSO-d ) δ 0.93–1.06 (7H, m, 2 × cyclopropyl–
6
CH and CH ), 1.80–1.82 (2H, m, –CH –), 2.00–2.03
2
3
2
(15 mmol) and sodium bicarbonate (15 mmol) dissolved
(2H, m, –CH –), 2.30–2.33 (2H, m, –CH –), 2.85–3.25
2 2
in water (10 mL) and methanol (10 mL) was added 3a–c
or 4a–c (5 mmol). The reaction mixture was stirred at
room temperature for 24 h. After removal of the solvent,
the residue was diluted with water (20 mL) and stirred
for 10 min and then filtered. The solid crude product was
purified by column chromatography (silica gel) eluted
with DCM to v (DCM):v (MeOH) = 10:1 to give the title
(
2
4
7H, m, piperazine–7H), 3.74–3.91 (7H, m, OCH and
3
× –CH –), 4.00–4.02 (1H, m, cyclopropyl–CH),
2
.14–4.21 (8H, m, 2 × NOMe and –CH –), 7.05–7.10
2
(
2H, m, Ar–H), 7.22–7.29 (2H, m, Ar–H), 7.40–7.50 (2H,
m, Ar–H), 7.62 (1H, d, Ar–H), 7.82 (1H, d, Ar–H), 7.89
(
[
1H, d, Ar–H), 8.41 (1H, s, C2–H). ESI-MS m/z: 808
M + H] . Elemental Anal. Calcd (%) for C H FN O :
+
43
46
7 8
3d–f and 4d–f.
C, 63.93; H, 5.74; N, 12.14; found: C, 63.69; H, 5.51; N,
1.87.
1
-Cyclopropyl-6-fluoro-8-methoxy-7-(4-(3-(3-(methoxyimino)-
1
2-oxoindolin-1-yl)propyl)-3-methylpiperazin-1-yl)-4-oxo-1,4-
3
-(5-Bromo-3-(methoxyimino)-2-oxoindolin-1-yl) propyl 7-
4-(3-(5-bromo-3-(methoxyimino)-2-oxoindolin-1-yl)propyl)-3-
methylpiperazin-1-yl)-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-
1,4-dihydroquinoline-3-carboxylate (4e).
dihydroquinoline-3-carboxylic acid formic acid salt (3d).
Yellow solid, yield: 41%. H NMR (400 MHz, DMSO-d6)
(
δ 0.94–1.07 (4H, m, 2 × cyclopropyl–CH ), 1.16 (3H, d,
Yellow solid,
2
CH ), 1.98–2.04 (2H, m, –CH –), 3.01–3.36 (7H, m,
yield: 54%. H NMR (400 MHz, DMSO-d ) δ 0.92–1.06
3
2
6
piperazine–7H), 3.80 (3H, s, OCH ), 3.89 (2H, t, –CH –),
(7H, m, 2 × cyclopropyl–CH and CH ), 1.76–1.81 (2H,
3
2
2
3
4.00–4.02 (1H, m, cyclopropyl–CH), 4.16–4.20 (5H, m,
m, –CH –), 1.99–2.02 (2H, m, –CH –), 2.29–2.33 (2H,
2 2
NOMe and –CH –), 7.03–7.07 (1H, m, Ar–H), 7.27 (1H,
m, –CH –), 2.90–3.23 (7H, m, piperazine–7H), 3.71–
2
2
d, Ar–H), 7.44 (1H, t, Ar–H), 7.62 (1H, d, Ar–H), 7.66
3.90 (7H, m, OCH and 2 × –CH –), 3.98–4.00 (1H,
3
2
(1H, d, Ar–H), 8.27 (1H, s, CHO), 8.42 (1H, s, C2–H).
m, cyclopropyl–CH), 4.16–4.24 (8H, m, 2 × NOMe
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

H.-D. Wang, Y.-L. Fan, J. Zhou, Y. Xu, and J. Guan
Vol 000
and –CH –), 7.19–7.25 (2H, m, Ar–H), 7.57–7.62 (2H,
m, Ar–H), 7.71 (1H, d, Ar–H), 7.88 (1H, s, Ar–H),
Acknowledgments. We gratefully acknowledge the financial
support by Zhejiang Provincial Natural Science Foundation
2
(
LQ16B050002) and Research Project of Zhejiang Provincial
8
9
.00 (1H, s, Ar–H), 8.39 (1H, s, C2–H). ESI-MS m/z:
64 [M + H] , 966 [M + 2 + H] , 968 [M + 4 + H] .
+
+
+
Department of Education (Y201533271).
Elemental Anal. Calcd (%) for C H FBr N O : C, 53.48;
43
44
2 7 8
H, 4.59; N, 10.15; found: C, 53.21; H, 4.22; N, 9.89.
REFERENCES AND NOTES
3
-(5-Fluoro-3-(methoxyimino)-2-oxoindolin-1-yl)
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1
-cyclopropyl-6-fluoro-7-(4-(3-(5-fluoro-3-(methoxyimino)-2-
[
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[
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[
[
48-well plate were filled with 100-mL twofold diluted
[
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À3
suspension containing 4 × 10 mg cells. Pure medium
replaced the diluted compounds in two wells as the
positive control of growth and deionized water instead of
the culture in other two wells as the negative control of
growth in the plates. The plates were covered and sealed,
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negative control wells should show obvious difference
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[
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet