Syntheses and binding affinities of 6-nitroquipazine analogues for serotonin transporter. Part 4: 3-Alkyl-4-halo-6-nitroquipazines

Article abstract of DOI:10.1016/j.bmc.2005.05.031

On the basis of the structure-activity relationship (SAR) of 4-chloro-6-nitroquipazine (K_i = 0.03 nM) and 3-fluoropropyl-6- nitroquipazine (K_i = 0.32 nM), 3-alkyl-4-halo-6-nitroquipazines were synthesized and tested for their potenti

Full text of DOI:10.1016/j.bmc.2005.05.031

Bioorganic & Medicinal Chemistry 13 (2005) 4952–4959
Syntheses and binding affinities of 6-nitroquipazine analogues
for serotonin transporter. Part 4: 3-Alkyl-4-halo-6-nitroquipazinesq
Byung Seok Moon, Byoung Se Lee and Dae Yoon Chi*
Department of Chemistry, Inha University, 253 Yonghyundong Namgu, Inchon 402-751, Republic of Korea
Received 1 April 2005; revised 13 May 2005; accepted 14 May 2005
Abstract—On the basis of the structure–activity relationship (SAR) of 4-chloro-6-nitroquipazine (Ki = 0.03 nM) and 3-fluoropropyl-
6-nitroquipazine (Ki = 0.32 nM), 3-alkyl-4-halo-6-nitroquipazines were synthesized and tested for their potential abilities in vitro to
displace [3H]citalopram binding to the rat cortical membranes. Binding affinities of 3b and 4d were Ki = 2.70 0.32 and
2.23 0.46 nM, respectively. The syntheses of 3-alkyl-4-halo-6-nitroquipazine, their in vitro binding affinities, and the SAR of
C3, C4 position in 6-nitroquipazine are described.
ꢀ 2005 Elsevier Ltd. All rights reserved.
1. Introduction
by F-18 radioisotope with short half-life (t1/2 =
110 min) for positron emission tomography (PET)
(Fig. 1). The biodistribution of 3-[18F]FPNQ was inves-
tigated using four mice each time (5, 15, 30, 60, 90,
120 min) postadministration. 3-[18F]FPNQ was local-
ized in frontal cortex, hippocampus, hypothalamus,
and olfactory tissues of murine brain at higher concen-
tration than the rest of the brain, showing results similar
to that of other SSRIs. Herein, we report the synthesis
and binding affinities of the compounds with both sub-
stituents, chlorine and bromine, at the C3 position and
with alkyl group at the C4 position.
The inhibition of the reuptake of serotonin (5-hydroxy-
tryptamine or 5-HT) results in the increase of 5-HT con-
centration in the neuronal synaptic cleft, affording to the
enhancement of signal transduction by 5-HT. For this
reason, a class of compounds called serotonin-specific
reuptake inhibitors (SSRIs) have been researched for
the treatment of serotonin-related psychiatric diseases
such as schizophrenia, anxiety, neurodegenaratives,
emesis, and depression.2,3 As the 5-HT concentration
in the brain is highly related to depression, the selective
inhibitors toward serotonin transporter (SERT) mainly
show the therapeutic effect for depression. Among the
many SERT inhibitors, it was reported that 6-nitroquip-
azine (6-NQ) has a subnanomolar binding affinity
(Ki = 0.17 nM) toward SERT.4,5
2. Chemistry
Compounds 4a–f were synthesized by the reaction of 4-
nitroaniline and excess diethyl alkylmalonates (more
than 10 equiv) without other solvent at 180 ꢁC for
Recently, our continued interest in 6-NQ derivatives led
to the synthesis of 4-chloro-6-NQ (Ki = 0.03 nM),4
which is more potent than 6-NQ itself, and 3-fluoropro-
pyl-6-NQ (3-FPNQ, Ki = 0.32 nM),6 which was labeled
Keywords: 6-Nitroquipazine; Serotonin transporter; 3-Alkyl-4-halo-6-
nitroquipazine; Structure–activity relationship.
q For Part 3, see Ref. 1.
*
Corresponding author. Tel.: +82 32 860 7686; fax: +82 32 867
5604.; e-mail: dychi@inha.ac.kr
Present address: Korea Institute of Radiological and Medical
Sciences, 215-4 Gongneung-dong, Nowon-ku, Seoul 139-709,
Republic of Korea.
Figure 1. Three compounds that have good binding affinities toward
serotonin transporter.
0968-0896/$ - see front matter ꢀ 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2005.05.031

B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
4953
16 h, followed by the removal of excess residue of dieth-
yl alkylmalonates by vacuum distillation. The ring for-
mations of 4a–f were carried out in polyphosporic acid
(PPA) at 120 ꢁC for 2.5 h to give 5a–f in moderate yield.
The reaction of 5a–f and phosphorus oxychloride gave
corresponding dichloro compounds 6a–f on heating at
80 ꢁC for 2.5 h. Dibromo compounds 7a–f were ob-
tained by bromination of 5a–f with phosphorus oxybro-
mide in dioxane under reflux. 3-Alkyl-4-chloro-6-NQs,
8a–f, and 3-alkyl-4-bromo-6-NQs, 9a–f, were synthe-
sized by the replacement of the halogen atom at the
C2 position with piperazine.
When the R group of compound 4 was either phenyl or
benzyl, compound 5 could not be synthesized. Com-
pounds 4 (R = phenyl and benzyl) were returned to
4-nitroaniline by hydrolysis of the amide bond under
the same conditions as in step b of Scheme 1. Thus,
3-phenyl- and 3-benzyl-4-chloro-6-NQs 14a and b were
prepared by another synthetic route shown in Scheme 2.
Scheme 2. Reagents and conditions: (a) diethyl phenylmalonate (for
10a), diethyl benzylmalonate (for 10b), pyridine, toluene, reflux, 18 h,
47 and 52%, respectively; (b) AlCl3, chlorobenzene, 120 ꢁC, 2 h, 90%,
97%; (c) POCl3, 80 ꢁC, 2.5 h, 59%, 65%; (d) (i) 1-piperazinecarbox-
aldehyde, 120 ꢁC, 4 h, (ii) 4 M H2SO4, THF, 50 ꢁC, 1 h, 65%, 61%;
(e) conc. HNO3, conc. H2SO4, 0 ꢁC, 30 min, 68%, 72%.
The condensation of aniline and excess diethyl phenyl-
and diethyl benzylmalonate provided compounds 10a
and b, respectively, in the presence of 1.5 equiv of pyri-
dine under refluxing toluene for 18 h. The ring-closed
compounds 11a and b were obtained by intramolecular
Friedel–Crafts acylation-type reaction in the presence
of aluminum chloride in chlorobenzene solvent. The
same reaction in other solvents such as toluene, nitro-
benzene, did not give the desired compounds 11a and
b. Compounds 13a and b were prepared by the reaction
of 11a and b and phosphorous oxychloride followed by
the introduction of piperazine at the C2 position on 12a
and b using 1-piperazine carboxaldehyde followed by
deprotection of N-formyl moiety under acidic condi-
tions without purification. Compounds 14a and b
gave nitro compounds 14a and b preferably under
Scheme 3.
normal nitration condition. As nitration was preformed
in the last step, the phenyl ring on C3 position was also
nitrated in the para position.
Furthermore, N-methylation of 8a using iodomethane
gives 15, which might be a potential C-11 (t1/2
=
20 min) labeled PET imaging agent as shown in
Scheme 3.
3. Binding studies
According to the method of our previous study4,6 using
crude synaptic membranes prepared from the cerebral
cortex of male Sprague–Dawley rats.7 Competition
binding assays were performed to measure the concen-
trations of test compounds that inhibited the specific
binding by 50% (IC50 values) using 1 nM [3H]citalopram
and 11 concentrations of the unlabeled compounds be-
tween 10À11 and 10À5 M. Nonspecific binding was de-
fined as that determined in the presence of 10 lM
fluoxetine. IC50 values were determined from the compe-
tition binding data using computer-assisted curve fitting
with GraphPad Prism 3.0 program. Inhibition binding
constant (Ki) values were subsequently calculated from
IC50 values using the Cheng–Prusoff equation.8 Table
1 illustrates the structures and the in vitro binding
affinities of 15 4-substituted derivatives of 6-NQ for
the 5-HT transporter, including 6-NQ, fluoxetine, and
paroxetine used as reference compounds.
Scheme 1. Reagents and conditions: (a) diethyl alkylmalonates,
180 ꢁC, 16 h, 57–72%; (b) PPA, 120 ꢁC, 2.5 h, 62–69%; (c) POCl3,
80 ꢁC, 2.5 h, 35–62% (X = Cl); POBr3, 1,4-dioxane, 100 ꢁC, 3 h,
32–48% (X = Br); (d) piperazine, DMF, 0 ꢁC, 1 h, 94–97% (X = Cl);
89–97% (X = Br).

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B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
Table 1. Binding affinities (Ki) for 5-HT transportera
Table 2. Trends of binding affinities (Ki) for 5-HT transporter by
increasing number of carbons on C3 position with halo derivatives on
C4 position
Compound
R4
R3
R2
Ki (nM)
0.03 0.01
R3
R4(nM)
Cl
3a
3b
Cl
Cl
Cl
Cl
Cl
Cl
Br
Br
Br
Br
Br
Br
Cl
Cl
Cl
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
CH3
H
Methyl
Ethyl
2.70 0.32
5.56 0.54
3.97 0.53
42.88 6.98
321.24 5.56
0.37 0.03
3.21 0.03
5.85 0.32
2.23 0.46
35.72 1.87
485.73 34.07
685.07
H
Br
0.37
3c
3d
n-Propyl
n-Butyl
i-Propyl
H
H
0.17
8.45
0.36
0.26
0.55
ND
0.03
2.70
3e
Methyl
Ethyl
3.21
5.85
3f
4a
5.56
3.97
n-Propyl
n-Butyl
i-Propyl
2.23
35.72
485.73
4b
4c
Methyl
Ethyl
42.88
321.24
4d
4e
n-Propyl
n-Butyl
i-Propyl
4-Nitro phenyl
4-Nitro benzyl
H
4f
14a
chains at the C3 position were similar for each analogue.
It is thought that only 6-NQ derivatives with halides
have an influence on property related to the size of the
halide. It might have narrow tolerance and change posi-
tion on C4 position at the binding site of the 5-HT reup-
take site. But, when 6-NQ with halogen adds to alkyl
chain in the C3 position it seems to compensate for
the activity that would be associated with the correct
binding position of the alkyl chain.
14b
15
330.86
17.28 2.33
0.17 0.03
22.13 1.77
0.53 0.08
1
H
Fluoxetine
Paroxetine
a The inhibition of [3H]citalopram binding was determined at 1 nM
[3H]citalopram for the various compounds listed. Binding data are
the means of three independent experiments. Eleven concentrations
of displacer were used for each determination. The Kd value of
[3H]citalopram, measured by Scatchard analysis of the equilibrium-
saturation experiment, was 1.12 nM.
In summary, the substitutent alkyl chain derivatives with
halide at the C4 position show increased binding affinity
and help to correct binding at 5-HT reuptake site. On
the basis of this result, alkyl chains provide a steric toler-
ance at the C3 position against 5-HT reuptake site.
4. Discussion
Fifteen 6-NQ derivatives were synthesized via 3-substi-
tuted quinoline-2,4-diones 5a–f and 11a–b from 4-nitro-
aniline or aniline. Table 1 shows the binding affinities of
these 15 6-NQ derivatives toward SERT measured by
the replacing ability of [3H]citalopram. Regardless of
whether it was 4-chloro or 4-bromo in 6-NQ, the bulkier
substituents at the C3 position showed relatively lower
binding affinities. As reported in a previous study,
4-chloro-6-NQ is 12 times more potent than 4-bromo-
6-NQ. It is thought that the size of the halogen atom
influences the nonpolar interaction between quinoline
ring and the nonpolar residue of SERT. Bringing
the two counterparts as close as possible will enhance
the interaction. Therefore, the chlorine atom in 6-NQ
must be situated between the two groups. When located
at an appropriate distance between the two groups, the
chlorine atom induces additional interaction. The bro-
mide atom seems to play a role in weakening the attrac-
tion by steric interaction with the nonpolar residue of
SERT. It is thought that the size of derivatives at the
C4 position influences the binding affinity (see Table 2).
5. Experimental
5.1. 2-Methyl-N-(4-nitrophenyl)malonamic acid ethyl
ester (4b)
The mixture of 4-nitroaniline (4.0 g, 29.0 mmol) and
diethyl methylmalonate (15 mL) was stirred at 180 ꢁC
for 18 h. After the reaction mixture was cooled, excess
malonate was removed by vacuum distillation. The res-
idue was diluted with 100 mL of water and extracted
with ethyl acetate (100 mL · 3). The combined organic
layer was dried (Na2SO4). The product 4b was obtained
as a yellow solid (5.5 g, 71%) by flash column chromat-
ography (50% CH2Cl2/hexane): 1H NMR (200 MHz,
CDCl3) d: 9.34 (br s, NH), 8.18 (d, J = 9.2 Hz, 2H),
7.79 (d, J = 9.2 Hz, 2H), 4.26 (q, J = 7.2 Hz, 2H), 3.54
(q, J = 7.3 Hz, 1H), 1.57 (d, J = 7.4 Hz, 3H), 1.32 (t,
J = 7.2 Hz, 3H); 13C NMR (50 MHz, CDCl3) d: 172.2,
167.7, 143.5, 124.9, 119.3, 62.0, 47.4, 15.0, 13.9; MS
(ESI) 267 (MH+). HRMS (EI): Calcd for C12H14N2O5
(M+) 266.0903. Found: 266.0906.
The C3 position of 6-NQ appears to have a space that is
associated with the nonpolar residue of SERT, because
the binding affinity showed moderate decrease from 3a
(H) to 3d (n-propyl) at C3 position of quinoline ring.
Although 4-bromo-6-NQ (4a) did not have good activity
compared to 4-chloro-6-NQ (3a), the binding affinities
of 4-chloro- and 4-bromo-6-NQs with increasing alkyl
5.2. 2-Ethyl-N-(4-nitrophenyl)malonamic acid ethyl ester
(4c)
This compound was prepared by the same method as for
4b. 4c: 67%, yellow solid; H NMR (200 MHz, CDCl3)
1

B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
4955
d: 9.40 (br s, NH), 8.20 (d, J = 9.0 Hz, 2H), 7.77 (d,
J = 9.0 Hz, 2H), 4.22–4.34 (m, 2H), 3.36 (t, J = 7.1 Hz,
1H), 2.08 (qt, 2H), 1.33 (t, J = 7.1 Hz, 3H), 1.03 (t,
J = 7.3 Hz, 3H); 13C NMR (50 MHz, CDCl3) d: 172.7,
167.1, 143.4, 125.0, 119.4, 62.0, 54.7, 25.3, 14.0, 11.6.;
MS (ESI) m/z: 281 (MH+). HRMS (EI): Calcd for
C13H16N2O5 (M+) 280.1059. Found: 280.1058.
122.6, 117.3, 114.0, 113.4, 107.0, 7.5; MS (ESI) m/z:
221 (MH+). HRMS (EI): Calcd for C10H8N2O4 (M+)
220.0484. Found: 220.0487.
5.7. 3-Ethyl-6-nitro-1H-quinoline-2,4-dione (5c)
This compound was prepared by the same method as for
5b. 5c: 66%, white solid; H NMR (200 MHz, DMSO-
1
5.3. 2-Propyl-N-(4-nitrophenyl)malonamic acid ethyl
ester (4d)
d6) d: 11.86 (br s, NH), 10.68 (br s, OH), 8.68 (d,
J = 2.6 Hz, 1H), 8.23 (dd, J = 9.0 and 2.6 Hz, 1H),
7.34 (d, J = 9.2 Hz, 1H), 2.55 (q, J = 7.3 Hz, 2H), 0.98
(t, J = 7.3 Hz, 3H); 13C NMR (50 MHz, DMSO-d6) d:
161.7, 154.3, 139.9, 139.3, 122.7, 117.5, 114.0, 113.5,
113.2, 14.6, 11.1; MS (ESI) m/z: 235 (MH+). HRMS
(EI): Calcd for C11H10N2O4 (M+) 234.0641. Found:
234.0651.
This compound 4d was prepared by the same method as
for 4b. 4d: 64%, yellow solid; 1H NMR (200 MHz,
CDCl3) d: 9.36 (br s, NH), 8.10 (d, J = 7.4 Hz, 2H),
7.72 (d, J = 7.4 Hz, 2H), 4.12–4.24 (m, 2H), 3.40 (t,
J = 7.4 Hz, 1H), 1.87–2.00 (m, 2H), 1.20–1.40 (m, 5H),
0.88 (t, J = 7.4 Hz, 3H); 13C NMR (50 MHz, CDCl3)
d: 171.9, 167.4, 143.5, 124.8, 119.3, 61.8, 53.3, 33.1,
20.3, 13.9, 13.4; MS (ESI) m/z: 295 (MH+). HRMS
(CI): Calcd for C14H19N2O5 (MH+) 295.1294. Found:
295.1303.
5.8. 3-Propyl-6-nitro-1H-quinoline-2,4-dione (5d)
This compound was prepared by the same method as for
5b. 5d: 62%, white solid; H NMR (200 MHz, DMSO-
1
d6) d: 11.83 (br s, NH), 8.66 (d, J = 2.6 Hz, 1H), 8.21
(dd, J = 8.8 and 2.6 Hz, 1H), 7.31 (d, J = 8.8 Hz, 1H),
3.49 (br s, OH), 2.49 (q, 2H), 1.38 (p, 2H), 0.87 (t,
J = 7.4 Hz, 3H); 13C NMR (50 MHz, DMSO-d6) d:
161.7, 154.7, 139.9, 139.3, 122.6, 117.5, 113.9, 113.4,
111.6, 23.2, 19.4, 12.1; MS (ESI) m/z: 249 (MH+).
HRMS (EI): Calcd for C12H12N2O4 (M+) 248.0797.
Found: 248.0804.
5.4. 2-n-Butyl-N-(4-nitrophenyl) malonamic acid ethyl
ester (4e)
This compound was prepared by the same method as for
4b. 4e: 69%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 9.36 (br s, NH), 8.20 (d, J = 9.2 Hz, 2H), 7.78 (d,
J = 9.2 Hz, 2H), 4.22–4.32 (m, 2H), 3.42 (t, J = 7.3 Hz,
1H), 2.00–2.01 (m, 2H), 1.28–1.37 (m, 7H), 0.87–0.94
(m, 3H); 13C NMR (50 MHz, CDCl3) d: 172.4, 167.3,
143.5, 124.9, 119.3, 61.9, 53.5, 31.2, 29.2, 22.1, 14.0,
13.6; MS (ESI) m/z: 309 (MH+). HRMS (EI): Calcd
for C15H20N2O5 (M+) 308.1372. Found: 308.1363.
5.9. 3-n-Butyl-6-nitro-1H-quinoline-2,4-dione (5e)
This compound was prepared by the same method as for
5b. 5e: 69%, white solid; H NMR (200 MHz, DMSO-
1
d6) d: 11.80 (br s, NH), 10.52 (br s, OH), 8.65 (d,
J = 2.6 Hz, 1H), 8.18 (dd, J = 8.8 and 2.6 Hz, 1H),
7.30 (d, J = 8.6 Hz, 1H), 2.48–2.55 (m, 2H), 1.31–1.33
(m, 4H), 0.84 (t, J = 6.8 Hz, 3H); 13C NMR (50 MHz,
DMSO-d6) d: 161.9, 154.5, 139.9, 139.3, 122.6, 117.4,
113.9, 113.4, 111.9, 28.3, 21.0, 20.4, 12.1; MS (ESI)
m/z: 263 (MH+). HRMS (EI): Calcd for C13H14N2O4
(M+) 262.0954. Found: 262.0959.
5.5. 2-Isopropyl-N-(4-nitrophenyl) malonamic acid ethyl
ester (4f)
This compound was prepared by the same method as for
4b. 4f: 61%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 9.40 (br s, NH), 8.21 (d, J = 9.2 Hz, 2H), 7.79 (d,
J = 9.2 Hz, 2H), 4.20–4.36 (m, 2H), 3.18 (d,
J = 9.2 Hz, 1H), 2.36–2.47 (m, 1H), 1.33 (t, J = 7.1 Hz,
3H), 1.07 (t, J = 6.7 Hz, 3H); 13C NMR (50 MHz,
CDCl3) d: 172.2, 166.6, 143.4, 124.8, 119.3, 61.8, 60.9,
32.1, 20.3, 13.9; MS (ESI) m/z: 295 (MH+). HRMS
(CI): Calcd for C14H19N2O5 (MH+) 295.1294. Found:
295.1295.
5.10. 3-Isopropyl-6-nitro-1H-quinoline-2,4-dione (5f)
This compound was prepared by the same method as for
5b. 5f: 61%, white solid; H NMR (200 MHz, DMSO-
1
d6) d: 11.74 (br s, NH), 8.75 (d, J = 2.6 Hz, 1H), 8.20
(dd, J = 9.2 and 2.6 Hz, 1H), 7.31 (d, J = 8.8 Hz, 1H),
3.34–3.41 (m, 1H), 1.23 (d, J = 7.0 Hz, 6H); 13C NMR
(50 MHz, DMSO-d6) d: 161.4, 154.2, 140.0, 139.3,
122.7, 117.8, 117.0, 113.8, 113.6, 22.6, 18.0; MS (ESI)
m/z: 249 (MH+). HRMS (EI): Calcd for C12H12N2O4
(M+) 248.0797. Found: 248.0785.
5.6. 3-Methyl-6-nitro-1H-quinoline-2,4-dione (5b)
2-Methyl-N-(4-nitrophenyl)malonamic acid ethyl ester
(4b, 10.0 g, 39.6 mmol) was added to 30 g of polyphos-
phoric acid and stirred for 2.5 h at 120 ꢁC. The reaction
mixture was poured in ice water and the precipitate was
filtered and then washed with 100 mL of ethyl acetate.
The product 5b was obtained as a white solid (5.5 g,
65%) by flash column chromatography (80% EtOAc/
hexane) or crystallization with methanol: 1H NMR
(200 MHz, DMSO-d6) d: 11.95 (br s, NH), 8.72 (d,
J = 2.6 Hz, 1H), 8.29 (dd, J = 9.2 and 2.6 Hz, 1H),
7.39 (d, J = 9.0 Hz, 1H), 2.02 (s, 3H); 13C NMR
(50 MHz, DMSO-d6) d: 162.2, 154.8, 139.7, 139.3,
5.11. 2,4-Dichloro-3-methyl-6-nitroquinoline (6b)
3-Methyl-6-nitro-1H-quinoline-2,4-dione (5b, 3.0 g,
13.9 mmol) was added to 20 mL of phosphorus oxychlo-
ride and stirred for 2.5 h at 80 ꢁC. The mixture was
cooled and evaporated. The product 6b was obtained
as a white solid (1.0 g, 45%) by flash column chromatog-
raphy (10% EtOAc/hexane): 1H NMR (200 MHz,

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B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
CDCl3) d: 9.09 (d, J = 2.2 Hz, 1H), 8.48 (dd, J = 9.2 and
2.2 Hz, 1H), 8.12 (d, J = 9.2 Hz, 1H), 2.73 (s, 3H); 13C
NMR (50 MHz, CDCl3) d: 155.5, 150.1, 147.9, 144.0,
135.7, 130.9, 130.6, 125.2, 123.8, 121.3, 18.0; MS (ESI)
m/z: 257 (MH+). HRMS (CI): Calcd for C10H7Cl2N2O2
(MH+) 256.9885. Found: 256.9884.
and dried over sodium sulfate. The product 7b was ob-
tained as a pale yellow solid (260 mg, 45%) by flash col-
1
umn chromatography (10% EtOAc/hexane): H NMR
(200 MHz, CDCl3) d: 9.12 (d, J = 2.6 Hz, 1H), 8.47
(dd, J = 9.2 and 2,6 Hz, 1H), 8.14 (d, J = 9.2 Hz, 1H),
2.85 (s. 3H); 13C NMR (50 MHz, CDCl3) d: 148.6,
148.5, 146.8, 136.6, 135.25, 130.8, 127.1, 124.3, 123.8,
24.0; MS (ESI) m/z: 347 (MH+). HRMS (CI): Calcd
for C10H7Br2N2O2 (MH+) 346.8854. Found: 346.8873.
5.12. 2,4-Dichloro-3-ethyl-6-nitroquinoline (6c)
This compound was prepared by the same method as for
6b. 6c: 39%, white solid; 1H NMR (200 MHz, CDCl3) d:
9.09 (d, J = 2.6 Hz, 1H), 8.48 (dd, J = 9.2 and 2.6 Hz,
1H), 8.11 (d, J = 9.2 Hz, 1H), 3.18 (q, J = 7.5 Hz, 2H),
1.33 (t, J = 7.5 Hz, 3H); 13C NMR (50 MHz, CDCl3)
d: 155.1, 148.0, 146.4, 143.8, 136.0, 123.8, 121.3, 25.3,
12.1; MS (ESI) m/z: 271 (MH+). HRMS (CI): Calcd
for C11H9Cl2N2O2 (MH+) 271.0041. Found: 271.0035.
5.17. 2,4-Dibromo-3-ethyl-6-nitroquinoline (7c)
This compound was prepared by the same method as for
7b. 7c: 36%, pale yellow solid; 1H NMR (200 MHz,
CDCl3) d: 9.11 (d, J = 2.2 Hz, 1H), 8.46 (dd, J = 9.2
and 2.2 Hz, 1H), 8.12 (d, J = 9.2 Hz, 1H), 3.27 (q,
J = 7.6 Hz, 2H), 1.32 (t, J = 7.6 Hz, 3H); 13C NMR
(50 MHz, CDCl3) d: 148.6, 148.0, 146.7, 140.0, 136.2,
130.8, 127.2, 124.3, 123.8, 30.7, 12.2; MS (ESI) m/z:
361 (MH+). HRMS (CI): Calcd for C11H9Br2N2O2
(MH+) 360.9011. Found: 360.9008.
5.13. 2,4-Dichloro-3-propyl-6-nitroquinoline (6d)
This compound was prepared by the same method as for
6b. 6d: 49%, white solid; 1H NMR (200 MHz, CDCl3) d:
9.13 (d, J = 2.6 Hz, 1H), 8.49 (dd, J = 9.2 and 2.6 Hz,
1H), 8.12 (d, J = 9.2 Hz, 1H), 3.08–3.17 (m, 2H), 1.69–
1.80 (m, 2H), 1.11 (t, J = 7.5 Hz, 3H); 13C NMR
(50 MHz, CDCl3) d: 153.0, 145.6, 143.9, 141.78, 132.4,
128.2, 122.9, 121.5, 119.1, 31.3, 11.1, 11.7; MS (ESI)
m/z: 285 (MH+). HRMS (CI): Calcd for C12H11Cl2N2O2
(MH+) 285.0198. Found: 285.0204.
5.18. 2,4-Dibromo-3-n-propyl-6-nitroquinoline (7d)
This compound was prepared by the same method as for
7b. 7d: 39%, pale yellow solid; 1H NMR (200 MHz,
CDCl3) d: 9.11 (d, J = 2.4 Hz, 1H), 8.45 (dd, J = 9.2
and 2.6 Hz, 1H), 8.12 (d, J = 9.2 Hz, 1H), 3.15–3.23
(m, 4H), 1.68–1.80 (m, 2H), 1.34 (t, J = 7.3 Hz, 3H);
13C NMR (50 MHz, CDCl3) d: 148.6, 148.3, 146.7,
138.9, 136.5, 130.8, 127.2, 124.3, 123.8, 38.9, 21.6,
14.2; MS (ESI) m/z: 375 (MH+). HRMS (CI): Calcd
for C12H11Br2N2O2 (MH+) 374.9167. Found: 374.9169.
5.14. 2,4-Dichloro-3-n-butyl-6-nitroquinoline (6e)
This compound was prepared by the same method as for
6b. 6e: 43%, white solid; 1H NMR (200 MHz, CDCl3) d:
9.12 (d, J = 2.6 Hz, 1H), 8.48 (dd, J = 9.2 and 2.2 Hz,
1H), 8.62 (d, J = 9.2 Hz, 1H), 3.10–3.18 (m, 2H), 1.48–
1.72 (m, 4H), 1.02 (t, J = 7.1 Hz, 3H); 13C NMR
(50 MHz, CDCl3) d: 155.4, 148.0, 146.5, 144.0, 135.2,
130.6, 125.4, 123.8, 121.4, 31.6, 30.1, 22.8, 13.7; MS
(ESI) m/z: 299 (MH+). HRMS (CI): Calcd for
C13H13Cl2N2O2 (MH+) 299.0354. Found: 299.0352.
5.19. 2,4-Dibromo-3-n-butyl-6-nitroquinoline (7e)
This compound was prepared by the same method as for
7b. 7e: 39%, pale yellow solid; 1H NMR (200 MHz,
CDCl3) d: 9.10 (d, J = 2.2 Hz, 1H), 8.45 (dd, J = 9.6
and 2.6 Hz, 1H), 8.11 (d, J = 9.6 Hz, 1H), 3.20 (t,
J = 7.8 Hz, 2H), 1.50–1.71 (m, 4H), 1.04 (t, J = 7.2 Hz,
3H); 13C NMR (50 MHz, CDCl3) d: 148.6, 148.3,
146.7, 139.1, 136.4, 130.8, 127.2, 124.3, 123.7, 36.9,
30.1, 22.8, 13.7; MS (ESI) m/z: 389 (MH+). HRMS
(CI): Calcd for C13H13Br2N2O2 (MH+) 388.9324.
Found: 388.9319.
5.15. 2,4-Dichloro-3-isopropyl-6-nitroquinoline (6f)
This compound was prepared by the same method as for
6b. 6f: 43%, white solid; 1H NMR (200 MHz, CDCl3) d:
9.18 (d, J = 2.2 Hz, 1H), 8.49 (dd, J = 9.2 and 2.6 Hz,
1H), 8.11 (d, J = 9.2 Hz, 1H), 4.05–4.19 (m, 1H), 1.55
(d, J = 7.0 Hz, 6H); 13C NMR (50 MHz, CDCl3) d:
147.7, 146.5, 144.1, 138.5, 130.5, 125.7, 123.9, 121.6,
118.1, 31.5, 19.3; MS (ESI) m/z: 285 (MH+); HRMS
(CI): Calcd for C12H11Cl2N2O2 (MH+) 285.0198.
Found: 285.0191.
5.20. 2,4-Dibromo-3-isopropyl-6-nitroquinoline (7f)
This compound was prepared by the same method as for
7b. 7f: 48%, pale yellow solid; 1H NMR (200 MHz,
CDCl3) d: 9.20 (d, J = 2.8 Hz, 1H), 8.45 (dd, J = 9.2
and 2.6 Hz, 1H), 8.11 (d, J = 9.2 Hz, 1H), 4.15–4.24
(m, 1H), 1.57 (d, J = 7.2 Hz, 6H); 13C NMR
(50 MHz, CDCl3) d: 148.2, 146.7, 141.9, 130.6, 128.8,
124.6 (m), 123.8, 35.7, 19.3; MS (ESI) m/z: 375
(MH+). HRMS (CI): Calcd for C12H11Br2N2O2
(MH+) 374.9167. Found: 374.9167.
5.16. 2,4-Dibromo-3-methyl-6-nitroquinoline (7b)
3-Methyl-6-nitro-1H-quinoline-2,4-dione (5b, 390 mg,
1.57 mmol) and phosphorus oxybromide (1.35 g,
4.71 mmol) were added to 30 mL of dried 1,4-dioxane
or chloroform and stirred for 3 h at 100 ꢁC. The mixture
was cooled and added to 30 mL of ethyl acetate and
then neutralized with saturated sodium bicarbonate
solution. The solution was extracted with ethyl acetate
5.21. 4-Chloro-3-methyl-6-nitroquipazine (8b)
2,4-Dichloro-3-methyl-6-nitroquinoline (6b, 540 mg,
2.10 mmol) in DMF (15 mL) solution was added to

B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
4957
piperazine (905 mg, 10.5 mmol) in DMF (3 mL) solu-
tion at 0 ꢁC and stirred for 30–60 min and then
quenched with excess water. After the precipitate was fil-
tered, it was dissolved in dichloromethane, then washed
by water and dried (Na2SO4). After removal of solvent,
the product 8b was obtained as a pale yellow solid
(620 mg, 96%) by flash column chromatography (10%
NH), 1.54 (d, J = 7.0 Hz, 6H); 13C NMR (50 MHz,
CDCl3) d: 164.5, 148.2, 144.1, 142.8, 134.4, 129.0,
123.8, 122.9, 120.7, 52.1, 45.7, 29.3, 19.7; MS (ESI) m/
z: 335 (MH+). HRMS (CI): Calcd for C16H20ClN4O2
(MH+) 335.1275. Found: 335.1275.
5.26. 4-Bromo-3-methyl-6-nitroquipazine (9b)
1
EtOAc/hexane): H NMR (200 MHz, CDCl3) d: 8.96
(d, J = 2.2 Hz, 1H), 8.32 (dd, J = 9.2 and 2.2 Hz, 1H),
7.83 (d, J = 9.2 Hz, 1H), 3.37–3.42 (m, 4H), 3.06–3.11
(m, 4H), 2.50 (s, 3H), 1.81 (br s, NH); 13C NMR
(50 MHz, CDCl3) d: 161.0, 146.2, 141.4, 141.1, 126.4,
122.5, 120.5, 120.0, 118.5, 48.6, 43.5, 15.1; MS (ESI)
m/z: 307 (MH+). HRMS (CI): Calcd for C14H16ClN4O2
(MH+) 307.0962. Found: 307.0969.
This compound was prepared by the same method as for
8b. 9b: 94%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 8.87 (d, J = 2.2 Hz, 1H), 8.24 (dd, J = 9.2 and 2.2 Hz,
1H), 7.76 (d, J = 9.2 Hz, 1H), 3.36–3.41 (m, 4H), 3.06–
3.11 (m, 4H), 2.52 (s, 3H), 1.98 (br s, NH); 13C NMR
(50 MHz, CDCl3) d: 163.1, 148.5, 143.9, 137.4, 128.8,
127.5, 123.8, 123.4, 122.7, 51.0, 45.9, 20.9; MS (ESI)
m/z: 351 (MH+). HRMS (CI): Calcd for C14H16BrN4O2
(MH+) 351.0457. Found: 351.0464.
5.22. 4-Chloro-3-ethyl-6-nitroquipazine (8c)
This compound was prepared by the same method as for
8b. 8c: 94%, yellow solid; H NMR (200 MHz, CDCl3)
5.27. 4-Bromo-3-ethyl-6-nitroquipazine (9c)
1
d: 8.94 (d, J = 2.2 Hz, 1H), 8.29 (dd, J = 9.2 and
2.2 Hz, 1H), 7.82 (d, J = 9.2 Hz, 1H), 3.36–3.40 (m,
4H), 3.07–3.12 (m, 4H), 2.96 (q, J = 7.5 Hz, 2H), 1.95
(br s, NH) 1.35 (t, J = 7.5 Hz, 3H); 13C NMR
(50 MHz, CDCl3) d: 163.6, 148.5, 144.0, 143.2, 131.4,
129.0, 122.9, 122.8, 120.9, 51.9, 45.9, 23.3, 12.9; MS
(ESI) m/z: 321 (MH+). HRMS (CI): Calcd for
C15H18ClN4O2 (MH+) 321.1118. Found: 321.1123.
This compound was prepared by the same method as for
8b. 9c: 97%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 8.99 (d, J = 2.6 Hz, 1H), 8.31 (dd, J = 9.0 and
2.6 Hz, 1H), 7.84 (d, J = 9.0 Hz, 1H), 3,34–3.39 (m,
4H), 2.96–3.12 (m, 6H), 1.85 (br s, NH), 1.33 (t,
J = 7.3 Hz, 3H); 13C NMR (50 MHz, CDCl3) d: 163.6,
148.6, 144.3, 136.9, 134.1, 129.1, 124.7, 123.8, 122.9,
52.1, 46.0, 26.2; MS (ESI) m/z: 365 (MH+). HRMS
(CI): Calcd for C15H18BrN4O2 (MH+) 365.0613. Found:
365.0619.
5.23. 4-Chloro-3-propyl-6-nitroquipazine (8d)
This compound was prepared by the same method as for
8b. 8d: 97%, yellow solid; H NMR (200 MHz, CDCl3)
5.28. 4-Bromo-3-propyl-6-nitroquipazine (9d)
1
d: 9.04 (d, J = 2.6 Hz, 1H), 8.36 (dd, J = 9.2 and 2.6 Hz,
1H), 7.88 (d, J = 9.2 Hz, 1H), 3.30–3.38 (m, 4H), 3.06–
3.11 (m, 4H), 2.87–2.94 (m, 2H), 1.71–1.80 (m, 2H),
1.03 (t, J = 7.4 Hz, 3H); 13C NMR (50 MHz, CDCl3)
d: 161.5, 146.2, 141.7, 140.9, 128.0, 126.6, 120.7, 120.5,
118.8, 49.5, 43.6, 29.8, 19.5, 12.0; MS (ESI) m/z: 335
(MH+). HRMS (CI): Calcd for C16H20ClN4O2 (MH+)
335.1275. Found: 335.1281.
This compound was prepared by the same method as for
8b. 9d: 95%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 8.99 (d, J = 2.6 Hz, 1H), 8.30 (dd, J = 9.0 and 2.6 Hz,
1H), 7.84 (d, J = 9.2 Hz, 1H), 3.32–3.37 (m, 4H), 3.06–
3.11 (m, 4H), 2.90–2.98 (m, 2H), 2.02 (br s, NH),
1.67–1.79 (m, 2H), 1.04 (t, J = 7.4 Hz, 3H); 13C NMR
(50 MHz, CDCl3) d: 161.4, 146.2, 141.9, 134.5, 130.6,
126.7, 122.3, 121.5, 120.4, 49.6, 43.6, 32.5, 19.8, 11.8;
MS (ESI) m/z: 379 (MH+). HRMS (CI): Calcd for
C16H20BrN4O2 (MH+) 379.0770. Found: 379.0775.
5.24. 4-Chloro-3-n-butyl-6-nitroquipazine (8e)
This compound was prepared by the same method as for
8b. 8e: 94%, yellow solid; H NMR (200 MHz, CDCl3)
5.29. 4-Bromo-3-n-butyl-6-nitroquipazine (9e)
1
d: 8.99 (d, J = 2.6 Hz, 1H), 8.33 (dd, J = 9.2 and
2.6 Hz, 1H) 7.86 (d, J = 9.2 Hz, 1H), 3.34–3.39 (m,
4H), 3.07–3.12 (m, 4H), 2.92 (t, J = 7.8 Hz, 2H), 2.32
(br s, NH), 1.61–1.76 (m, 2H), 1.36–1.54 (m, 2H), 0.99
(t, J = 7.2 Hz, 3H); 13C NMR (50 MHz, CDCl3) d:
163.9, 148.6, 144.2, 143.2, 130.6, 129.1, 123.2, 122.9,
121.1, 51.9, 45.9, 30.6, 29.9, 22.9, 13.7; MS (ESI) m/z:
349 (MH+). HRMS (CI): Calcd for C17H22ClN4O2
(MH+) 349.1431. Found: 349.1437.
This compound was prepared by the same method as for
8b. 9e: 94%, yellow solid; H NMR (200 MHz, CDCl3)
1
d: 9.01 (d, J = 2.2 Hz, 1H), 8.32 (dd, J = 9.2 and
2.2 Hz, 1H), 7.86 (d, J = 9.2 Hz, 1H), 3.32–3.37 (m,
4H), 3.09–3.11 (m, 4H), 2.97 (t, J = 7.9 Hz, 2H), 1.86
(br s, NH), 1.60–1.72 (m, 2H), 1.40–1.50 (m, 2H), 0.99
(t, J = 7.2 Hz, 3H); 13C NMR (50 MHz, CDCl3) d:
163.9, 148.7, 144.4, 136.9, 133.3, 129.2, 124.8, 123.9,
122.9, 52.2, 46.0, 32.7, 30.9, 22.9, 13.7; MS (ESI) m/z:
393 (MH+). HRMS (CI): Calcd for C17H22BrN4O2
(MH+) 393.0926. Found: 393.0930.
5.25. 4-Chloro-3-isopropyl-6-nitroquipazine (8f)
This compound was prepared by the same method as for
8b. 8f: 96%, yellow solid; H NMR (200 MHz, CDCl3)
5.30. 4-Bromo-3-isopropyl-6-nitroquipazine (9f)
1
d: 9.02 (d, J = 2.2 Hz, 1H), 8.30 (dd, J = 9.2 and
2.2 Hz, 1H), 7.84 (d, J = 9.2 Hz, 1H), 3.60–3.67 (m,
1H), 3.30–3.67 (m, 4H), 3.08–3.13 (m, 4H), 2.39 (br s,
This compound was prepared by the same method as for
8b. 9f: 96%, yellow solid; H NMR (200 MHz, CDCl3)
d: 9.12 (d, J = 2.6 Hz, 1H), 8.32 (dd, J = 9.2 and
1

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B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
2.6 Hz, 1H) 7.84 (d, J = 9.2 Hz, 1H), 3.66–3.80 (m, 1H),
3.28–3.33 (m, 4H), 3.07–3.12 (m, 4H), 2.24 (br s, NH),
1.55 (d, J = 7.0 Hz, 6H); 13C NMR (50 MHz, CDCl3)
d: 164.7, 148.3, 144.5, 136.8, 135.3, 129.2, 125.4, 123.7,
123.0, 51.3, 45.8, 30.5, 20.0; MS (ESI) m/z: 379
(MH+). HRMS (CI): Calcd for C16H20BrN4O2 (MH+)
379.0770. Found: 379.0764.
5.35. 2,4-Dichloro-3-phenylquinoline (12a)
This compound was prepared by the same method as for
6b. 12a: 59%, white solid; H NMR (200 MHz, CDCl3)
1
d: 8.25 (d, J = 8.2 Hz, 1H), 8.08 (d, J = 8.4 Hz, 1H),
7.77–7.85 (m, 1H), 7.64–7.71 (m, 1H), 7.48–7.56 (m,
3H), 7.26 (m, 2H); 13C NMR (50 MHz, CDCl3) d:
150.4, 147.0, 143.2, 135.9, 133.3, 131.1, 129.7, 128.9,
128.7, 128.5, 128.1, 125.7, 124.9; MS (ESI) m/z: 274
(MH+). HRMS (CI): Calcd for C15H10Cl2N (MH+)
274.0190. Found: 274.0186.
5.31. 2,N-Diphenylmalonamic acid ethyl ester (10a)
Aniline (3.0 g, 32.2 mmol), diethyl phenyl malonate
(11.4 g, 48.3 mmol), and pyridine (5.2 mL, 64.4 mmol)
were added to 50 mL of toluene and stirred for 18 h at
120 ꢁC. The solvent of reaction mixture was evaporated
and the desired product 10a was obtained as a brown
solid (4.2 g, 47%) by flash column chromatography
5.36. 3-Benzyl-2,4-dichloroquinoline (12b)
This compound was prepared by the same method as for
6b. 12b: 65%, white solid; 1H NMR (200 MHz, CDCl3) d:
8.14 (d, J = 8.4 Hz, 1H), 7.99 (d, J = 8.4 Hz, 1H), 7.70 (t,
J = 7.5 Hz, 1H), 7.54 (t, J = 7.5 Hz, 1H), 7.17–7.26 (m,
5H), 4.47 (s, 2H); 13C NMR (50 MHz, CDCl3) d: 151.7,
146.4, 143.8, 137.2, 130.6, 128.7, 128.4, 125.8, 124.5,
36.9; MS (ESI) m/z: 288 (MH+). HRMS (CI): Calcd for
C16H12Cl2N (MH+) 288.0347. Found: 288.0343.
1
(10% EtOAc/hexane): H NMR (200 MHz, CDCl3) d:
9.16 (br s, NH), 7.42–7.51 (m, 4H), 7.20–7.35 (m, 5H),
7.05 (t, J = 7.3 Hz, 1H), 4.67 (s, 1H), 4.14–4.26 (m,
2H), 1.22 (t, J = 7.1 Hz, 3H); 13C NMR (50 MHz,
CDCl3) d: 170.6, 165.3, 137.5, 133.9, 128.9, 128.7,
128.2, 124.4, 120.0, 61.9, 59.0, 13.8; MS (ESI) m/z: 284
(MH+). HRMS (EI): Calcd for C17H17NO3 (M+)
283.1208. Found: 283.1203.
5.37. 4-Chloro-3-phenylquipazine (13a)
5.32. 2-Benzyl-N-phenylmalonamic acid ethyl ester (10b)
In a pressure tube, 2,4-dichloro-3-phenylquinoline 12a
(900 mg, 3.3 mmol) was added to 1-piperazinecarboxal-
dehyde (5 mL) and stirred for 4 h at 120 ꢁC. The reac-
tion mixture was cooled and diluted with sodium
bicarbonate solution and then extracted with ethyl ace-
tate. The organic layer was evaporated and the residue
was dissolved in THF (20 mL). The solution was added
to 4 M H2SO4 (20 mL) and stirred for 1 h at 50 ꢁC. The
reaction mixture was poured in ice water (100 mL) and
basified with 1 N NaOH and then extracted with dichlo-
romethane. The organic layer was dried with sodium
sulfate and evaporated. The product 13a was obtained
as a yellow oil (692 mg, 65%) by flash column chromat-
ography (10% MeOH/CH2Cl2): 1H NMR (200 MHz,
CDCl3) d: 8.13 (d, J = 8.4 Hz, 1H), 7.85 (d, J = 8.4 Hz,
1H), 7.63 (t, J = 6.9 Hz, 1H), 7.37–7.47 (m, 6H), 3.10–
3.15 (m, 4H), 2.64–2.69 (m, 4H); 13C NMR (50 MHz,
CDCl3) d: 159.7, 146.7, 141.7, 136.7, 130.3, 129.9,
128.2, 127.7, 127.6, 127.2, 124.6, 123.3, 50.3, 45.5; MS
(ESI) m/z: 324 (MH+). HRMS (CI): Calcd for
C19H19ClN3 (MH+) 324.1268. Found: 324.1262.
This compound was prepared by the same method as for
10a. 10b: 52%, brown solid; 1H NMR (200 MHz,
CDCl3) d: 8.70 (br s, NH), 7.44–7.49 (m, 2H), 7.03–
7.29 (m, 8H), 4.09 (q, J = 5.3 Hz, 2H), 3.68 (t,
J = 7.5 Hz, 1H), 3.29 (q, 2H), 1.12 (t, J = 7.1 Hz, 3H);
13C NMR (50 MHz, CDCl3) d: 171.1, 165.9, 137.5,
137.4, 128.8, 128.4, 126.7, 124.4, 120.1, 61.5, 55.4,
36.5, 13.8; MS (ESI) m/z: 298 (MH+). HRMS (EI):
Calcd for C18H19NO3 (M+) 297.1365. Found: 297.1376.
5.33. 3-Phenyl-1H-quinoline-2,4-dione (11a)9
2,N-Diphenylmalonamic acid ethyl ester (10a, 3.7 g,
13.1 mmol) was dissolved in 50 mL chlorobenzene and
aluminum chloride (5.2 g, 39 mmol) was added in three
portions. The mixture was heated to 120 ꢁC and stirred
for 2 h. The reaction mixture was quenched by ice water
and extracted with ethyl acetate, and dried (Na2SO4).
The product 11a was obtained as a pale yellow solid
(3.02 g, 97%) by flash column chromatography (10%
MeOH/CH2Cl2): 1H NMR (200 MHz, CD3OD) d:
7.45–7.52 (m, 4H), 7.06–7.10 (m, 5H), 6.96–6.99 (m,
1H), 4.89 (s, 1H); 13C NMR (50 MHz, CD3OD) d:
177.1, 171.8, 139.1, 137.9, 129.7, 129.5, 128.3, 125.6,
121.7, 62.1.
5.38. 3-Benzyl-4-chloroquipazine (13b)
This compound was prepared by the same method as for
13a. 13b: 61%, white solid; 1H NMR (200 MHz, CD3OD)
d: 8.07 (d, J = 8.4 Hz, 1H), 7.85 (d, J = 8.6 Hz, 1H), 7.64
(t, J = 7.4 Hz, 1H), 7.43 (t, J = 7.5 Hz, 1H), 7.07–7.24
(m, 5H); 13C NMR (50 MHz, CD3OD) d: 162.9, 147.6,
145.0, 140.1, 131.0, 129.5, 129.0, 128.9, 127.9, 127.2,
127.0, 125.5, 125.0, 51.6, 46.0, 36.2; MS (ESI) m/z: 338
(MH+). HRMS (CI): Calcd for C20H21ClN3 (MH+)
338.1424. Found: 338.1426.
5.34. 3-Benzyl-1H-quinoline-2,4-dione (11b).10
Compound was prepared by the same method as for
11a. 11b: 90%, pale yellow solid; H NMR (200 MHz,
1
DMSO-d6) d: 10.16 (br s, NH), 7.54 (d, J = 7.6 Hz,
2H), 7.11–7.32 (m, 6H), 7.03 (t, J = 7.3 Hz, 1H), 4.27
(br s, OH), 3.79 (t, J = 7.5 Hz, 1H), 3.12 (d,
J = 7.2 Hz, 2H); 13C NMR (50 MHz, DMSO-d6) d:
168.8, 165.1, 137.2, 137.0, 127.0, 126.9, 126.4, 124.4,
121.7, 117.6, 52.7, 32.5.
5.39. 4-Chloro-6-nitro-3-(4-nitrophenyl)quipazine (14a)
Concentrated HNO3 (14.1 mmol, 640 lL) was added
dropwise to a solution of 4-chloro-3-phenylquipazine

B. S. Moon et al. / Bioorg. Med. Chem. 13 (2005) 4952–4959
4959
(13a, 1.0 g, 3.08 mmol) in concentrated H2SO4 (15 mL)
at 0 ꢁC and stirred for 30 min. The reaction mixture
was poured in ice water (100 mL) and basified with
4 N NaOH and then extracted with dichloromethane.
The organic layer was dried with sodium sulfate and
evaporated. The product 14a was obtained pale as a yel-
low solid (867 mg, 68%) by flash column chromato-
graphy (10% MeOH/CH2Cl2): 1H NMR (200 MHz,
CDCl3) d: 9.07 (d, J = 2.4 Hz, 1H), 8.38–8.47 (m, 3H),
7.89 (d, J = 9.2 Hz, 1H), 7.69 (d, J = 8.8 Hz, 1H),
3.22–3.26 (m, 4H), 2.70–2.75 (m, 4H); 13C NMR
(50 MHz, CDCl3) d: 158.2, 147.5, 145.1, 141.3, 140.8,
140.4, 128.7, 126.3, 123.5, 121.9, 121.5, 119.4, 119.1,
47.7, 42.9; MS (ESI) m/z: 414 (MH+). HRMS (CI):
Calcd for C19H17ClN5O4 (MH+) 414.0969. Found:
414.0962.
J = 9.2 Hz, 1H), 7.17 (s, 1H), 3.80–3.85 (m, 4H), 2.52–
2.57 (m, 4H), 2.37 (s, 3H); 13C NMR (50 MHz, CDCl3)
d: 158.0, 151.8, 144.4, 142.4, 127.6, 124.3, 121.2, 119.7,
110.5, 54.7, 46.0, 44.8; MS (ESI) m/z: 307 (MH+).
HRMS (CI): Calcd for C14H16ClN4O2 (MH+)
307.0962. Found: 307.0965.
5.42. In vitro serotonin transporter binding studies
As described in Section 3, we have measured the binding
affinities according to the method published in our pre-
vious studies1,4,6 using crude synaptic membranes pre-
pared from the cerebral cortex of male Sprague–
Dawley rats. See the detailed procedure in our previous
study.6
5.40. 4-Chloro-6-nitro-3-(4-nitrobenzyl)quipazine (14b)
Acknowledgment
This compound was prepared by the same method as for
14a. 14b: 72%, yellow solid; 1H NMR (200 MHz, CDCl3)
d: 9.04 (d, J = 2.6 Hz, 1H), 8.44 (dd, J = 9.2 and 2.6 Hz,
1H), 8.17 (d, J = 8.6 Hz, 2H), 7.96 (d, J = 9.2 Hz, 1H),
7.33 (d, J = 8.4 Hz, 2H), 4.62 (s, 2H), 3.28–3.33 (m, 4H),
2.98–3.03 (m, 4H); 13C NMR (50 MHz, CDCl3) d:
163.7, 149.3, 146.9, 145.6, 145.4, 144.5, 129.4, 128.6,
126.1, 123.9, 123.9, 122.8, 121.3, 51.7, 45.8, 36.0; MS
(ESI) m/z: 428 (MH+). HRMS (CI): Calcd for
C20H19ClN5O4 (MH+) 428.1126. Found: 428.1129.
This work was supported by Inha University grant,
2005.
References and notes
1. Lee, B. S.; Chu, S.; Lee, B.-S.; Chi, D. Y.; Song, Y. S.; Jin,
C. Bioorg. Med. Chem. Lett. 2002, 12, 811.
2. Lucki, I. Biol. Psychiat. 1998, 44, 151.
3. Frazer, A. J. Clin. Psychiat. 1997, 6, 9.
4. Lee, B. S.; Chu, S.; Lee, B. C.; Chi, D. Y.; Choe, Y. S.;
Jeong, K. J.; Jin, C. Bioorg. Med. Chem. Lett. 2000, 10,
1559.
5. Blakely, R.; Berson, H.; Fremeau, R.; Caron, M.; Peek,
M.; Prince, H.; Bradely, C. Nature 1991, 354, 66.
6. Lee, B. S.; Chu, S.; Lee, K. C.; Lee, B. S.; Chi, D. Y.;
Choe, Y. S.; Kim, S. E.; Song, Y. S.; Jin, C. Bioorg. Med.
Chem. 2003, 11, 4949.
7. Zukin, S. R.; Young, A. B.; Snyder, S. H. Proc. Natl.
Acad. Sci. U.S.A. 1974, 71, 4802.
8. Cheng, Y. C.; Prusoff, W. H. Biochem. Pharmacol. 1973,
22, 3099.
9. Manley, P. J.; Bilodeau, M. T. Org. Lett. 2004, 6, 2433.
10. Klasek, A.; Koristek, K.; Polis, J.; Kosmrlj, J. Tetrahedron
2000, 56, 1551.
5.41. 4-Chloro-2-(4-methylpiperazin-1-yl)-6-nitroquino-
line (15)
4-Chloro-6-nitroquipazine (2, 450 mg, 1.54 mmol),
KOH (230 mg, 4.1 mmol) and methyl iodide (170 lL,
2.8 mmol) were added to DMF (15 mL) and stirred for
1 h at rt. The reaction mixture was quenched by water
and extracted with ethyl acetate and then dried. The
product 15 was obtained yellow solid (339 mg, 72%)
by flash column chromatography (3% MeOH/CH2Cl2):
1H NMR (200 MHz, CDCl3) d: 8.92 (d, J = 2.6 Hz,
1H), 8.34 (dd, J = 9.2 and 2.6 Hz, 1H), 7.67 (d,