Synthesis and biological evaluation of 2-substituted quinoline 6-carboxamides as potential mGluR1 antagonists for the treatment of neuropathic pain

Article abstract of DOI:10.1248/cpb.c13-00945

A series of 2-amino and 2-methoxy quinoline-6-carboxamide derivatives have been synthesized and their metabotropic glutamate receptor type 1 (mGluR1) antagonistic activities were evaluated in a functional cell-based assay. The compound 13c showed the highest potency with IC₅₀ value of 2.16μM against mGluR1. Finally, in vivo evaluation of 13c in the rat spinal nerve ligation (SNL) model exhibited weak analgesic effects with regard to both mechanical allodynia and cold allodynia.

Full text of DOI:10.1248/cpb.c13-00945

508
Regular Article
Chem. Pharm. Bull. 62(6) 508–518 (2014)
Vol. 62, No. 6
Synthesis and Biological Evaluation of 2-Substituted Quinoline
6-Carboxamides as Potential mGluR1 Antagonists for the Treatment of
Neuropathic Pain
Younghee Kim,a,b Jiwon Son,c Juhyeon Kim,d Du-Jong Baek,b Yong Sup Lee,c Eun Jeong Lim,a
,a,d
,a,d
Jae Kyun Lee,a Ae Nim Pae,a,d Sun-Joon Min,* and Yong Seo Cho*
a Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology (KIST); Hwarangno
b
14-gil 5, Seongbuk-gu, Seoul 136–791, Republic of Korea: Department of Chemistry, College of Natural Sciences,
c
Sangmyung University; Seoul 110–743, Republic of Korea: College of Pharmacy, 1 Hoegi-dong, Dongdaemun-gu,
d
Kyunghee University; Seoul 130–701, Republic of Korea: and Department of Biological Chemistry, Korea University
of Science and Technology (UST); 176 Gajung-dong, 217 Gajungro, Yuseong-gu, Daejeon 305–333, Republic of
Korea.
Received December 5, 2013; accepted March 6, 2014
A series of 2-amino and 2-methoxy quinoline-6-carboxamide derivatives have been synthesized and
their metabotropic glutamate receptor type 1 (mGluR1) antagonistic activities were evaluated in a functional
cell-based assay. The compound 13c showed the highest potency with IC50 value of 2.16µM against mGluR1.
Finally, in vivo evaluation of 13c in the rat spinal nerve ligation (SNL) model exhibited weak analgesic effects
with regard to both mechanical allodynia and cold allodynia.
Key words glutamate; metabotropic glutamate receptor (mGluR); quinoline; neuropathic pain; spinal nerve
ligation (SNL) model
Glutamate is the excitatory neurotransmitter in the central mGluR1 agonists can induce spontaneous pain behavior which
nerve system (CNS). The signaling action of glutamate is can be reduced by the effect of mGluR1 antagonists.24,25)
regulated through glutamate receptors, which contribute to Furthermore, treatment of neuropathic pain model (by con-
the glutamate-mediated postsynaptic excitation of neural cells. striction injury of the sciatic nerve) with selective mGluR1
Thus, they play an important role in neural communication, antibodies significantly attenuated cold hyperalgesia and me-
memory formation, learning, and regulation.1)
chanical allodynia.26) These evidences have supported a role
There are two kinds of glutamate receptors, ionotropic for mGluR1 in neuropathic pain states.
glutamate receptors (iGluRs) and metabotropic glutamate
To date, several mGlu1 negative allosteric modulators
receptors (mGluRs) according to their activation mechanism (NAMs) have been discovered and proved to be effective in
triggering a postsynaptic current. iGluRs rapidly form the ion vivo experiments.27) For examples, A-841720 (1), a potent and
channel pore upon binding to glutamate, whereas mGluRs mGluR1 antagonist, achieved excellent efficacy at 100µmol/kg
indirectly activate ion channels on the plasma membrane via (ED50=22µmol/kg, intraperitoneally (i.p.)) in the spinal nerve
a G-protein signaling pathway. mGluRs belong to family C G ligation (SNL) model of neuropathic pain.28) JNJ16259685 (2)
protein-coupled receptors (GPCRs) characterized by a large exhibited an excellent mGluR1 antagonistic activity with IC50
extracellular domain that contains the glutamate binding site. value of 1.21nM, and its in vivo efficacy has been reported in
There are eight different types of mGluRs, labeled mGluR1 to the rat formalin.29) In addition, morphine-like analgesic effects
mGluR8, divided into three groups based on their sequence were observed with compound 3 in an elecrtomyogpraph
similarity, signal transduction and pharmacology.2)
pinch model (EPM).30)
mGluR1, one of the receptors in Group I, is predominantly
During our efforts toward development of novel drugs for
localized in the postsynaptic region and widely distributed in treatment of neuropathic pain, we have initiated a program
the CNS including hippocampus, cerebellum, thalamic nuclei to discover mGluR1 NAMs as potential therapeutic targets.
and spinal cord. Stimulating the mGluR1 causes phospho- Considering the structures of several mGluR1 NAMs (Fig. 1),
lipase C (PLC) to hydrolyze phosphoinositide into inositol we have designed quinoline derivatives having a set of amines
triphosphate (IP3), which in turn binds to the IP3 receptor on the both substituents R1 and R2, which were illustrated in
on the endoplasmic reticulum, elevating intracellular calcium Fig. 2. In particular, in comparison with mGluR1 antagonists
levels.3,4)
2, 3 and 431) in Fig. 1, we assumed that hydrophobic groups at
According to the previous studies, mGluR1 is involved in R1 and cyclic amino carbonyl groups at R2 could be crucial
various CNS related disorders such as epilepsy,5,6) anxiety,7–9) inhibitory components. Furthermore, change of these substitu-
stroke,10) psychotic disorder11–13) and pain.14–21) In particular, ents in quinolines might mediate drug-like properties to im-
the role of glutamate and mGluR1 in pain states has been well prove in vitro metabolic stability of the designed compounds.
studied. Glutamate, released from primary afferent neurons,
In this study, we report our progress in the synthesis of
may be responsible for persistent activation of spinal neurons 2,6-disubsituted quinolines as potential mGluR1 NAMs and
and hypersensitivity to painful stimuli.22,23) Pharmacologi- their biological evaluation for treatment of neuropathic pain.
cal studies have shown that the intrathecal administration of
Results and Discussion
Chemistry The synthesis of compounds 12–16 is de-
The authors declare no conflict of interest.
© 2014 The Pharmaceutical Society of Japan
*To whom correspondence should be addressed. e-mail: sjmin@kist.re.kr;
ys4049@kist.re.kr

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Fig. 1. Representative mGluR1 Negative Allosteric Modulators
Fig. 2. The Structure of Quinoline Derivatives 5
Reagents and conditions: a) (COCl)2, 0°C to rt, 12h then 120°C, 30m, 89%; b) 4-bromoaniline, pyr, DCM, rt, 3h, 80%; c) H2SO4, 0°C to rt, 3h, 89%; d) POCl3, 120°C,
6h, 99%; e) various amines (neat) or NaOMe, MeOH (for R1=OMe) 80–110°C, 6–40h, 66–93%; f) nBuLi, CO2 (g), THF, −78°C to rt, 1–3h then 1N HCl, 37–86%;
g) HBTU, amines, TEA, DMF, 23–110°C, 24h, 5–93%; h) CuCN, Pd(PPh3)4, DMF, 120°C, 48h, 93%; i) KOH, tBuOH, 100°C, 24h, 97%; j) MeBr, 50% aq. NaOH,
Bu4NHSO4, PhH, 100°C, 2.5h, 18% (12b), 71% (12c).
Chart 1. Synthesis of 2-Substituted Quinoline-6-carboxamides 12–16
scribed in Chart 1. Following the literature procedure,32,33) we of amides, which was easily separated by column chromatog-
first prepared 6-bromoquinolin-2(1H)-one 8 in three steps; raphy to afford 12b and 12c.
formation of acyl chloride, amidation with 4-bromoaniline
Biological Assay The mGluR1 antagonistic activities of
and cyclization. Treatment of 8 with POCl3 afforded the our synthesized compounds 12–16 were examined by a func-
corresponding 2-chloroquinoline 9, which was subjected to tional cell based assay measuring the ability of the compounds
coupling reactions with various amines or sodium methoxide to inhibit the mobilization of calcium by a high concentra-
to give 2-substitued 6-bromoquniolines 10. Lithiation of 10 tion of glutamate in human mGluR1/HEK293 cells using
followed by addition of CO2 gas led to formation of carboxylic FDSS6000 system. Investigating the effect of cyclic amines
acids 11.29) Finally, amide coupling reactions of 11 with a set at the 2-position of quinolines, we found that 2-pyrrolidyl or
of amines in the presence of O-(benzotriazol-1-yl)-N,N,N′,N′- 2-piperidinylquinolines 12 and 13 showed considerably good
tetramethyluronium hexafluorophosphate (HBTU) gave quino- inhibitory activities with higher than 40% inhibition values at
line derivatives 12–16. Alternatively, we successfully obtained the concentration of 10µM when small amide groups (R2=Me
compound 17 using palladium-catalyzed coupling reactions or Et, and R3=H) were located at the 6-position of quinolines.
to introduce a cyano group to quinolines 10 at the 6-position. On the other hand, when R1 was piperazine, 4-methyl/ethyl-
Hydrolysis of 17 followed by methylation34) yielded a mixture piperazine, or morpholine, most quinoline derivatives except

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Vol. 62, No. 6
14h and 15b exhibited weak antagonistic activity (% inhibi- ropathic pain. Oral administration of 13c was able to reduce
tion values <40%) regardless of 6-amide substituents. Ad- both mechanical allodynia and cold allodynia, but its efficacy
ditionally, we replaced cyclic amines with methoxy substitu- was not superior to that of gabapentin. Thus, the present study
ent at R1. However, such a modification did not significantly described herein could be further applied for the identification
improve a negative modulation of mGluR1. In fact, the highest of more potent mGluR1 NAMs with high in vivo efficacy for
inhibitory value increased up to only 58% at the concentra- treatment of neuropathic pain.
tion of 10µM when R2 and R3 are equal to cyclopropyl and
hydrogen. Based on the structure–activity relationship (SAR)
information from Table 1, the important pharmacophore com-
Experimental
Chemistry All reactions were conducted using oven-dried
ponents are summarized in Fig. 3. Indeed, a hydrophobic and glassware under an atmosphere of nitrogen (N2). All com-
larger substituent (cyclic amine) at R1 is responsible for high mercially available reagents were purchased and used without
potency for mGluR1. The size of a secondary amide group at further purification. Solvents Et2O, CH2Cl2, and tetrahydro-
the 6-position of quinolines seems to be another essential fac- furan (THF) were dried and distilled following usual proto-
tor to enhance mGluR1 antagonistic activity.
cols. Reactions were followed by TLC analysis using silica gel
Considering the structural diversity of 12–16 as well as plates with fluorescent indicator (60F-254) using UV lamp and
the in vitro activity data, we then selected 12b, 13c and 13d KMnO4 solution with heat as visualizing agents. Flash chro-
to achieve additional experiments to examine mGluR1 IC50 matography was carried out using silica gel (60, particle size
1
values, human ether-à-go-go-related gene (hERG) inhibition, 0.040–0.063mm). The H-NMR spectra were measured with
microsomal stability, and CYP inhibition. The results are 400MHz and 13C-NMR spectra were measured with 100MHz
1
summarized in Table 2. We observed the highest mGluR1 an- using CDCl3. H-NMR chemical shifts are expressed in parts
tagonistic activity with compound 13c (IC50=2.16 µM). While per million (δ) downfield to CHCl3 (δ=7.26), 13C-NMR chemi-
three compounds displayed excellent metabolic stability in cal shifts are expressed in parts per million (δ) relative to
human liver microsomes, they moderately inhibited the activ- the central CDCl3 resonance (δ=77.0). Coupling constants in
ity of CYP isozymes at the concentration of 10µM. Neverthe- 1H-NMR are in Hz. The following abbreviations were used to
less, we decided to choose compound 13c as a lead compound designate multiplicities: s=singlet, d=doublet, t=triplet, q=
for in vivo study on the basis of the overall pharmacological quartet, quint.=quintet, m=multiplet, br=broad. High resolu-
properties including in vitro potency, low hERG inhibition tion mass spectra (HR-MS) were obtained using positive elec-
and microsomal stability. Thus, the in vivo efficacy of 13c was trospray ionization and mass/charge (m/z) ratios are reported
evaluated in the spinal nerve ligation (SNL) neuropathic pain as values in atomic mass units. Fourier transform infrared
model35) (Fig. 4). In order to induce a neuropathic pain state (FT-IR) analyses were obtained on a Perkin-Elmer Spectrum
of rats, the L5 spinal nerve at a site distal to the DRG was GX FT-IR system and were reported in cm−1.
tightly ligated. We executed two behavioral tests (mechani-
(E)-N-(4-Bromophenyl)-3-ethoxyacrylamide (7): Ethyl vinyl
cal allodynia and cold allodynia) after two weeks of surgical ether (10.0mL, 104mmol) was added dropwise to oxalyl chlo-
operation. The oral administration of the rats with 100mg/ ride (13.5mL, 157mmol) at 0°C under nitrogen gas. After
kg of compound 13c was performed when gabapentin was stirred for 1h, the reaction was allowed to warm to room
used as a positive control. In case of mechanical allodynia, temperature and stirred for additional 12h. Excessive oxalyl
13c exhibited only the half efficacy of pain reduction at 3h in chloride was removed under reduce pressure with an aid of
comparison with that of gabapentin. We also observed moder- dichloromethane. Then, the reaction mixture was stirred at
ate paw withdrawal response at 3h and 5h after administra- 120°C for 30min. After cooled to room temperature, the reac-
tion in the experiment of cold allodynia. This result indicated tion vessel was placed in vacuo to afford the corresponding
1
that the efficacy of compound 13c is not comparable to that of acyl chloride (12.5g, 89%) as a brown oil: H-NMR (CDCl3)
gabapentin yet. Thus, further optimization of compound 13c δ: 1.37 (3H, t, J=7.1Hz), 4.01 (2H, q, J=7.1Hz), 5.48 (1H,
is necessary to develop 2,6-disubstituted quinoline derivatives d, J=12.1Hz), 7.76 (1H, d, J=12.1Hz); 13C-NMR (CDCl3) δ:
as mGluR1 antagonists for treatment of neuropathic pain. In 168.1, 164.7, 102.9, 68.8, 14.4. To a mixture of 4-bromoani-
addition, evaluation of synthesized compounds for their selec- line (8.80g, 65.4mmol) and pyridine (8.80mL, 109mmol) in
tivity against the other subtypes of the mGluR family should CH2Cl2 was slowly added the above acryloyl chloride (9.34g,
be considered for next lead optimization.
54.3mmol). The reaction mixture was stirred for 3h at room
temperature, quenched with excess ice fragments, and fil-
tered through a sintered glass funnel covered with a pad of
Conclusion
In summary, we have synthesized a series of novel 2-amino Celite to afford crude solid. This material was washed with
or 2-methoxyquinoline 6-carboxamides 12–16 and evaluated dichloromethane to give amide 7 (11.1g, 80%) as a pink solid,
their mGluR1 antagonistic activities. We found that 13 com- which was used in the next step without further purification:
pounds in this series showed good potencies with inhibition 1H-NMR (DMSO-d6) δ: 9.82 (brs, 1H), 7.41 (m, 5H), 5.45
values over 40% at the concentration of 10µM. Based on the (d, J=11.9Hz, 1H), 3.90 (q, J=6.3Hz, 2H), 1.22 (t, J=7.0Hz,
structure–activity relationship of those compounds, we rec- 3H); 13C-NMR (DMSO-d6) δ: 165.2, 160.3, 139.5, 131.9, 121.3,
ognized that a hydrophobic cyclic amine at R1 and a small 114.6, 100.1, 67.0, 14.9; Purity: (HPLC) 98.81%.
size of secondary amide comprising R2 and R3 could have
6-Bromoquinolin-2(1H)-one (8): Sulfuric acid (29.0mL,
a significant impact on the inhibitory activity of quinoline 544mmol) was added to (E)-N-(4-bromophenyl)-3-ethoxy-
derivatives against mGluR1. Examination of pharmacological acrylamide (11.2g, 45.9mmol) at 0°C under N2 (g). The
properties of several hit compounds led to compound 13c as a mixture was stirred for 3h at room temperature. The reac-
potential lead, which was evaluated in rat SNL model of neu- tion was quenched by transferring the reaction mixture to

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Table 1. In Vitro Inhibitory Activity of the Synthesized Compounds against mGluR1
% Inhibition (mGluR1)a)
Compounds
R1
R2
R3
10µM
1µM
12a
12b
12c
12d
12e
12f
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Pyrrolidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperidine
Piperazine
Piperazine
Piperazine
4-Methylpiperazine
4-Methylpiperazine
4-Ethylpiperazine
4-Ethylpiperazine
4-Ethylpiperazine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
Morpholine
MeO-
H
H
16.55
65.97
35.85
56.22
47.15
44.07
15.65
16.78
25.84
15.57
30.22
72.86
21.90
76.76
61.97
46.75
5.98
24.75
33.14
14.68
11.35
2.71
Methyl
Methyl
Ethyl
H
Methyl
H
H
H
H
H
Propyl
Octyl
18.06
14.82
20.71
20.91
20.03
14.98
33.59
11.34
32.71
24.80
26.29
9.61
12g
12h
12i
Phenyl
Benzyl
Morpholine
12j
4-(4-Fluorophenyl)piperazine
12k
13a
13b
13c
13d
13e
13f
4-(2,4-Dimethylphenyl)piperazine
Methyl
Methyl
H
Methyl
Ethyl
H
H
Propyl
Propyl
Propyl
H
Isopropyl
Cyclopropyl
Phenyl
13g
13h
13i
H
56.21
9.29
9.89
H
16.94
24.03
11.79
0.99
Benzyl
H
21.07
24.50
13.84
28.73
18.80
16.50
9.31
13j
Morpholine
4-Phenylpiperazine
13k
14a
14b
14c
14d
14e
14f
Ethyl
Propyl
H
H
−4.98
0.64
Propyl
H
2.85
Methyl
H
16.38
17.15
4.05
Isopropyl
Methyl
Isopropyl
Methyl
H
H
23.15
15.01
22.70
40.89
30.25
48.80
13.99
16.45
29.63
31.45
27.03
35.38
31.43
28.68
6.85
Methyl
14g
14h
15a
15b
15c
15d
15e
15f
H
8.50
H
10.89
5.68
H
H
Methyl
Ethyl
19.35
13.61
24.30
14.08
4.07
H
Propyl
H
Isopropyl
Methyl
Propyl
H
Methyl
Propyl
H
15g
15h
15i
11.12
8.35
Cyclohexyl
4-(4-Fluorophenyl)piperazine
2,4-(Dimethylphenyl)piperazine
16.93
−0.46
5.04
15j
16a
16b
16c
16d
16e
16f
Methyl
Methyl
H
Methyl
H
MeO-
3.09
16.73
27.45
15.82
27.34
13.12
16.67
11.40
MeO-
Ethyl
53.09
38.41
58.10
−0.51
23.95
32.97
MeO-
Isopropyl
Cyclopropyl
H
MeO-
H
MeO-
Pyrrolidine
Piperidine
16g
16h
MeO-
MeO-
4-Methylpiperazine
a) Ca2+ flux assay using glutamate as agonist.
ice fragments. At this point, the color of the reaction mixture 95.39%.
turned to pink. After the ice melted, the quenched mixture 6-Bromo-2-chloroquinoline (9): A mixture of 6-bromo-
was filtered and washed with sufficient H2O to afford bromo- quinolin-2(1H)-one 8 (804mg, 3.59mmol) and phosphorous
1
quinoline 6 (9.10g, 89%) as a pink solid: H-NMR (DMSO-d6) oxychloride (3.00mL, 3.22mmol) was stirred at 120°C for
δ: 11.84 (brs, 1H), 7.91 (d, J=9.6Hz, 1H), 7.86 (d, J=9.6Hz, 6h. The reaction was quenched by transferring the reaction
1H), 7.62 (dd, J1=2.2, J2=8.8Hz, 1H), 7.23 (d, J=8.8Hz, 1H), mixture to ice fragments. Then, 4N NaOH solution was slowly
6.53 (d, J=9.6Hz, 1H); 13C-NMR (DMSO-d6) δ: 162.1, 139.6, added. The resulting solution was separated and extracted with
138.4, 133.3, 130.4, 123.6, 121.3, 117.7, 113.8; Purity: (HPLC) EtOAc. The organic layer was separated, dried over MgSO4,

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Vol. 62, No. 6
Fig. 3. Structure–Activity Relationship (SAR) Study of the Synthesized Compounds
Table 2. The Results of IC50 (mGluR1 and hERG Channel), Microsomal Stability, and CYP Inhibition
CYP (% remaining at 10µM)
mGluR1 IC50
hERG IC50
HLM % remaining
Compounds
(µM)a)
(µM)a)
after 30min
1A2
2D6
2C9
3A4
2C19
12b
13c
13d
3.10 0.84
2.16 0.53
4.57 0.57
10.10 4.46
10.20 3.28
—
>99
>99
94.5
15.72
15.27
13.53
44.42
35.80
6.15
26.11
25.59
33.07
6.85
9.73
9.96
39.83
17.20
37.85
a) IC50 value ( S.D.) was obtained from a dose–response curve.
Fig. 4. Effect on Mechanical Allodynia (A, B) and Cold Allodynia (C, D) after Oral Administration of Gabapentin (○, 100mg/kg, n=4) and 13c (●,
100mg/kg, n=6) to Neuropathic Pain-Induced Rats
Experimental time expressed as d for days after neuropathic injury (N) and h for hours after gabapentin or 13c administration, *p<0.05 (gabapentin), *p<0.05 (13c) vs.
pre-administration value (paired t-test), ♣ p<0.05 gabapentin vs. 13c (unpaired t-test).
and filtered. The solvent was removed under reduced pressure moquinolines (10a–e) A mixture of 6-bromo-2-chloroquino-
to afford chloroquinoline 9 (863mg, 99%) as a brownish solid, line 9 (2.50mmol) and amines (for 10a–e) or sodium methox-
which was used in the next step without further purification: ide in MeOH (for 10g) was stirred at 90°C on an oil bath for
1H-NMR (DMSO-d6) δ: 8.42 (1H, dd, J=2.5, 8.7Hz), 8.35 (1H, 6–40h. The reaction was quenched by excessive water and
d, J=2.0Hz), 7.94 (1H, dt, J=2.3, 9.0Hz), 7.89 (1H, dd, J=2.6, the resulting solution was extracted with EtOAc. The organic
8.7Hz), 7.65 (1H, dd, J=2.5, 8.6Hz); 13C-NMR (DMSO-d6) δ: layer was separated, dried over MgSO4, and filtered. The sol-
150.8, 146.33, 139.7, 134.4, 130.6, 130.5, 128.5, 124.0, 120.6; vent was removed under reduced pressure to give the crude
Purity: (HPLC) 98.21%.
product, which was purified by column chromatography over
General Procedure for Preparing 2-Substituted-6-bro- silica gel (CH2Cl2–MeOH) to afford 2-aminoquinoline 10a–g.

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6-Bromo-2-(pyrrolidin-1-yl)quinoline (10a): Yield 93%; 1.97–1.96 (m, 4H); 13C-NMR (DMSO-d6) δ: 167.9, 156.7, 151.0,
1H-NMR (CDCl3) δ: 7.73 (d, J=9.1Hz, 1H), 7.69 (s, 1H), 7.55 138.3, 130.9, 129.6, 125.9, 123.4, 121.7, 111.8, 47.0, 25.4; MS:
(s, 2H), 6.72 (d, J=9.0Hz, 1H), 3.60 (brs, 4H), 2.06–2.02 (m, m/z (EI-MS) 242 (M+); Purity: (HPLC) 91.36%.
4H); 13C-NMR (CDCl3) δ: 155.8, 147.3, 135.9, 132.4, 129.4,
2-(Piperidin-1-yl)quinoline-6-carboxylic Acid (11b): Yield
127.9, 123.8, 113.7, 111.1, 46.8, 25.5. MS: m/z (electron ioniza- 83%; 1H-NMR (DMSO-d6) δ: 12.7 (brs, 1H), 8.31 (d,
tion (EI)-MS) 276 (M+). Purity: (HPLC) 98.88%.
J=1.7Hz, 1H), 8.10 (d, J=9.3Hz, 1H), 7.95 (dd, J1=8.7Hz,
6-Bromo-2-(piperidin-1-yl)quinoline (10b): Yield 67%; J2=1.9Hz, 1H), 7.50 (d, J=8.8Hz, 1H), 7.27 (d, J=9.3Hz, 1H),
1H-NMR (CDCl3) δ: 7.70 (d, J=9.2Hz, 1H), 7.67 (d, J=1.7Hz, 3.76–3.73 (m, 4H), 1.65–1.55 (m, 6H); 13C-NMR (DMSO-d6)
1H), 7.54 (dd, J1=8.9Hz, J2=2.0Hz, 1H), 7.51 (d, J=8.9Hz, δ: 168.0, 158.2, 150.5, 138.7, 130.6, 129.7, 126.1, 124.2, 121.8,
1H), 6.95 (d, J=9.2Hz, 1H), 3.71–3.69 (m, 4H), 1.71–1.62 (m, 111.0, 45.8, 25.8, 24.8; Purity: (HPLC) 99.02%.
6H); 13C-NMR (CDCl3) δ: 157.6, 146.9, 136.2, 132.4, 129.1,
2-(4-(tert-Butoxycarbonyl)piperazin-1-yl)quinoline-6-
128.2, 123.9, 114.6, 110.5, 46.1, 25.8, 24.8. MS: m/z (EI-MS) carboxylic Acid (11c): Yield 37%; 1H-NMR (DMSO-d6) δ:
290 (M+); Purity: (HPLC) 99.36%.
12.8 (brs, 1H), 8.38 (d, J=2.0Hz, 1H), 8.21 (d, J=9.2Hz,
tert-Butyl 4-(6-Bromoquinolin-2-yl)piperazine-1-carboxylate 1H), 8.01 (dd, J1=8.7Hz, J2=2.0Hz, 1H), 7.58 (d, J=8.8Hz,
1
(10c): Yield 80%; H-NMR (CDCl3) δ: 7.70 (d, J=9.2Hz, 1H), 1H), 7.31 (d, J=9.3Hz, 1H), 3.78–3.76 (m, 4H), 3.48–3.46 (m,
7.65 (d, J=2.0Hz, 1H), 7.53 (dd, J1=8.9Hz, J2=2.0Hz, 1H), 4H), 1.44 (s, 1H); 13C-NMR (DMSO-d6) δ: 180.1, 171.8, 158.0,
7.49 (d, J=8.9Hz, 1H), 6.87 (d, J=9.2Hz, 1H), 3.67–3.64 (m, 154.9, 139.0, 131.4, 130.0, 126.3, 123.1, 121.9, 110.1, 80.4, 44.8,
4H), 3.53–3.50 (m, 4H), 1.45 (s, 9H); 13C-NMR (CDCl3) δ: 33.8, 28.4; MS: m/z (EI-MS) 356 [(M−H)+].
157.2, 154.8, 146.4, 136.5, 132.7, 129.2, 128.4, 124.3, 115.3,
110.3, 80.0, 44.9, 43.8, 28.5; Purity: (HPLC) 90.23%.
2-(4-Methylpiperazin-1-yl)quinoline-6-carboxylic
(11d): Yield 86%; H-NMR (MeOD) δ: 8.25 (s, 1H), 8.08 (d,
Acid
1
6-Bromo-2-(4-methylpiperazin-1-yl)quinoline (10d): Yield J=8.6Hz, 1H), 8.01 (d, J=9.2Hz, 1H), 7.55 (d, J=8.6Hz, 1H),
67%; 1H-NMR (CDCl3) δ: 7.75 (d, J=9.2Hz, 1H), 7.69 (d, 7.14 (d, J=9.2Hz, 1H), 3.88–3.86 (m, 4H), 2.88–2.85 (m, 4H),
J=1.5Hz, 1H), 7.56 (dd, J1=9.0Hz, J2=1.9Hz, 1H), 7.52 (d, 2.53 (s, 3H); 13C-NMR (MeOD) δ: 178.3, 157.7, 149.0, 138.6,
J=8.9Hz, 1H), 6.95 (d, J=9.2Hz, 1H), 3.74 (t, J=4.9Hz, 4H), 130.7, 130.0, 129.1, 125.2, 122.3, 109.8, 53.6, 43.6, 43.4; MS:
2.53 (t, J=5.0Hz, 4H), 2.34 (s, 3H); 13C-NMR (CDCl3) δ: m/z (EI-MS) 319 (M+).
157.3, 146.6, 136.3, 132.6, 129.2, 128.4, 124.2, 115.0, 110.2,
54.9, 46.2, 44.9; MS: m/z (EI-MS) 305 (M+); Purity: (HPLC) Yield 44%; 1H-NMR (CD3OD) δ: 8.29 (s, 1H), 8.11 (d,
99.32%. J=8.5Hz, 1H), 7.99 (d, J=8.8Hz, 1H), 7.57 (d, J=8.6Hz, 1H),
2-(4-Ethylpiperazin-1-yl)quinoline-6-carboxylic acid (11e):
6-Bromo-2-(4-ethylpiperazin-1-yl)quinoline (10e): Yield 7.10 (d, J=8.6Hz, 1H), 3.90 (bs, 4H), 2.98 (brs, 4H), 2.86
66%; 1H-NMR (CDCl3) δ: 7.71 (d, J=9.2Hz, 1H), 7.66 (d, (q, J=7.1Hz, 2H), 1.25 (t, J=7.2Hz, 3H); 13C-NMR (MeOD)
J=1.4Hz, 1H), 7.54 (dd, J1=9.0Hz, J2=2.0Hz, 1H), 7.51 (d, δ: 172.5, 157.6, 149.1, 138.7, 129.9, 129.6, 129.3, 125.3, 122.3,
J=9.0Hz, 1H), 6.91 (d, J=9.2Hz, 1H), 3.72 (t, J=5.2Hz, 109.8, 51.8, 51.5, 43.3, 9.3.
4H), 2.53 (t, J=5.1Hz, 4H), 2.43 (q, J=7.2Hz, 2H), 1.10 (t,
2-Methoxyquinoline-6-carboxylic Acid (11f): Yield 78%;
J=7.2Hz, 3H); 13C-NMR (CDCl3) δ: 157.4, 146.6, 136.4, 132.6, 1H-NMR (CD3OD) δ: 8.49 (d, J=1.9Hz, 1H), 8.19 (d,
129.2, 128.4, 124.2, 115.0, 110.2, 52.7, 52.4, 44.9, 12.0; MS: J=8.8Hz, 1H), 8.18 (d, J=8.8Hz, 1H), 7.82 (d, J=8.7Hz, 1H),
m/z (EI-MS) 319 (M+); Purity: (HPLC) 99.35%.
6.99 (d, J=8.9Hz, 1H), 4.06 (s, 3H); 13C-NMR (CD3OD) δ:
4-(6-Bromoquinolin-2-yl)morpholine (10f): Yield 94%; 167.8, 164.0, 147.4, 141.3, 130.5, 130.0, 126.7, 125.5, 124.1,
1H-NMR (CDCl3) δ: 7.72 (d, J=9.2Hz, 1H), 7.70 (s, 1H), 7.53 113.0, 53.7.
(t, J=9.7Hz, 2H), 6.87 (d, J=9.1Hz, 1H), 3.80 (t, J=4.7Hz,
4H), 3.65 (t, J=4.7Hz, 4H).
General Procedure for Preparing Compounds 12–16 To
a N,N-dimethylformamide (DMF) solution of 2-morpholino-
6-Bromo-2-methoxyquinoline (10g): Yield 92%; 1H-NMR quinolone-6-carboxylic acid (0.05mmol), HBTU (0.059mmol),
(CDCl3) δ: 7.86 (d, J=8.9Hz, 1H), 7.84 (d, J=2.1Hz, 1H), 7.71 and amine (0.05mmol) was added triethylamine (0.15mmol).
(d, J=8.9Hz, 1H), 7.67 (dd, J1=8.9Hz, J2=2.1Hz, 1H), 6.90 The mixture was stirred at room temperature for 12h. The
(d, J=8.8Hz, 1H), 4.05 (s, 3H); 13C-NMR (CDCl3) δ: 162.6, resulting mixture was poured into water, and extracted with
145.3, 137.6, 132.7, 129.5, 129.0, 126.3, 117.2, 114.1, 53.5.
EtOAc. The crude mixture was purified by column chroma-
General Procedure for Preparing Compounds 11a–f tography over silica gel (40:1 CH2Cl2–methanol+1% triethyl-
To a solution of 6-bromoquinolines 10 (5.00mmol) in THF amine) to give the products, which were recrystallized by
(35mL) cooled to −78°C was slowly added n-BuLi (1.6M in CH2Cl2–hexane to afford the products 12–16.
hexane, 7.50mmol). After the resulting solution was stirred
2-(Pyrrolidin-1-yl)quinoline-6-carboxamide (12a): Yield
at −78°C for 20min, CO2 gas generated from dry ice was 97%; 1H-NMR (DMSO-d6) δ: 8.20 (d, J=1.9Hz, 1H), 7.99
transferred to the reaction mixture via cannula. The reaction (d, J=9.1Hz, 1H), 7.92 (dd, J1=8.8Hz, J2=2.9Hz, 2H), 7.48
was slowly allowed to warm up to room temperature for 2h (d, J=8.7Hz, 1H), 7.22 (brs, 4H), 6.99 (d, J=9.1Hz, 1H),
and then poured into water. The addition of 1N HCl (up to pH 3.38 (brs, 4H), 1.97–1.95 (m, 4H); 13C-NMR (DMSO-d6) δ:
5) led to formation of yellow solid, which was filtered through 168.3, 156.5, 150.1, 138.1, 128.5, 128.4, 127.0, 125.6, 121.6,
sintered glass to afford quinoline carboxylic acid 11a–f. The 111.8, 47.0, 25.5; MS: m/z (EI-MS) 241 (M+); Purity: (HPLC)
products were completely dried under vacuum and used in the 97.68%.
next step without further purification.
N-Ethyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12d):
2-(Pyrrolidin-1-yl)quinoline-6-carboxylic Acid (11a): Yield Yield 46%; 1H-NMR (CDCl3) δ: 8.06 (s, 1H), 7.84 (d,
1
62%; H-NMR (DMSO-d6) δ: 12.7 (brs, 1H), 8.32 (s, 1H), J=9.0Hz, 1H), 7.82 (d, J=8.7Hz, 1H), 7.69 (d, J=8.7Hz,
8.10 (d, J=9.1Hz, 1H), 7.95 (dd, J1=8.8Hz, J2=1.6Hz, 1H), 1H), 6.72 (d, J=9.1Hz, 1H), 6.24 (brs, 1H), 3.62 (brs, 4H),
7.51 (d, J=8.7Hz, 1H), 6.91 (d, J=9.1Hz, 1H), 3.54 (brs, 4H), 3.52 (q, J=6.7Hz, 2H), 2.05–2.01 (m, 4H), 1.25 (t, J=7.2Hz,

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3H); 13C-NMR (CDCl3) δ: 167.3, 156.3, 150.2, 150.0, 137.8, J=9.1Hz, 1H), 3.81 (m, 4H), 3.63 (m, 4H), 2.90 (m, 4H), 2.30
127.5, 127.2, 125.9, 121.7, 111.1, 47.0, 35.0, 25.5, 15.0; MS: m/z (s, 3H), 2.28 (s, 3H), 2.07–2.04 (m, 4H); 13C-NMR (CDCl3)
(EI-MS) 269 (M+); Purity: (HPLC) 91.27%.
δ: 170.8, 156.3, 149.4, 148.5, 137.2, 133.2, 132.7, 131.9, 128.3,
N-Propyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12e): 128.1, 127.4, 127.1, 126.0, 121.9, 119.2, 111.0, 52.3, 46.9, 30.9,
1
Yield 9%; H-NMR (CD3OD) δ: 8.13 (d, J=1.9Hz, 1H), 8.01 25.5, 20.7, 17.7; Purity: (HPLC) 92.40%.
(d, J=9.2Hz, 1H), 7.93 (dd, J1=8.8Hz, J2=2.0Hz, 1H), 7.67
N-Methyl-2-(piperidin-1-yl)quinoline-6-carboxamide (13a):
1
(d, J=8.9Hz, 1H), 6.93 (d, J=9.2Hz, 1H), 3,65–3.61 (m, 4H), Yield 42%; H-NMR (CDCl3) δ: 8.04 (d, J=2.9Hz, 1H), 7.83
3.36 (t, J=7.2Hz, 2H), 2.10–2.05 (m, 4H), 1.72–1.60 (m, 2H), (d, J=9.2Hz, 1H), 7.82 (dd, J1=8.7Hz, J2=2.1Hz, 1H), 7.66 (d,
0.99 (t, J=7.4Hz, 3H); 13C-NMR (CDCl3) δ: 167.3, 155.8, J=8.6Hz, 1H), 6.97 (d, J=9.3Hz, 1H), 6.40 (s, 1H), 3.76–3.75
149.1, 138.2, 127.53, 127.49, 127.4, 125.3, 121.6, 111.2, 47.2, (m, 4H), 1.85 (d, J=9.1Hz, 3H), 1.68–1.66 (m, 6H); 13C-NMR
41.9, 25.5, 23.0, 11.5; MS: m/z (EI-MS) 283 (M+); Purity: (CDCl3) δ: 168.1, 157.8, 149.6, 138.2, 127.6, 127.2, 127.1, 126.1,
(HPLC) 95.05%.
N-Octyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12f): Purity: (HPLC) 96.20%.
121.7, 110.4, 46.2, 26.9, 25.8, 24.7; MS: m/z (EI-MS) 269 (M+);
1
Yield 30%; H-NMR (CDCl3) δ: 8.05 (d, J=2.0Hz, 1H), 7.85
N,N-Dimethyl-2-(piperidin-1-yl)quinoline-6-carboxamide
(d, J=9.0Hz, 1H), 7.81 (dd, J1=8.8Hz, J2=2.1Hz, 1H), 7.66 (d, (13b): Yield 29%; 1H-NMR (CDCl3) δ: 7.85 (d, J=9.2Hz,
J=8.7Hz, 1H), 6.73 (d, J=9.1Hz, 1H), 6.20 (s, 1H), 3.61 (brs, 1H), 7.70 (d, J=1.7Hz, 1H), 7.67 (d, J=8.2Hz, 1H), 7.57 (dd,
4H), 3.45 (q, J=6.7Hz, 2H), 2.06–2.00 (m, 4H), 1.65–1.58 (m, J1=8.6Hz, J2=1.8Hz, 1H), 7.01 (d, J=9.2Hz, 1H), 3.77–3.76
2H), 1.41–1.36 (m, 2H), 1.33–1.24 (m, 8H), 0.86 (t, J=6.9Hz, (m, 4H), 3.10 (brs, 6H), 1.71 (brs, 6H); 13C-NMR (CDCl3)
3H); 13C-NMR (CDCl3) δ: 167.4, 156.4, 150.3, 137.6, 127.4, δ: 171.8, 157.9, 137.5, 129.3, 128.3, 126.8, 126.2, 121.9, 115.2,
127.1, 127.0, 126.1, 121.7, 111.1, 46.9, 40.2, 31.8, 30.0, 29.3, 110.3, 46.1, 39.5, 35.6, 25.8, 24.8; MS: m/z (EI-MS) 283 (M+);
29.2, 27.1, 25.5, 22.6, 14.1; MS: m/z (EI-MS) 353 (M+); Purity: Purity: (HPLC) 96.93%.
(HPLC) 91.75%.
N-Ethyl-2-(piperidin-1-yl)quinoline-6-carboxamide
(13c):
N-Phenyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12g): Yield 43%; 1H-NMR (CDCl3) δ: 8.03 (s, 1H), 7.83 (d,
1
Yield 68%; H-NMR (CDCl3) δ: 8.17 (d, J=1.9Hz, 1H), 7.94 J=9.2Hz, 1H), 7.80 (d, J=8.8Hz, 1H), 7.62 (d, J=8.6Hz, 1H),
(dd, J1=8.8Hz, J2=5.0Hz, 1H), 7.90 (d, J=9.0Hz, 2H), 7.73 6.97 (d, J=9.3Hz, 1H), 6.17 (brs, 1H), 3.74–3.73 (m, 4H),
(d, J=8.8Hz, 1H), 6.67 (d, J=7.7Hz, 2H), 7.39 (d, J=7.6Hz, 3.55–3.46 (m, 2H), 1.66 (brs, 6H), 1.24 (t, J=7.2Hz, 3H);
1H), 7.37 (d, J=8.1Hz, 1H), 7.14 (t, J=7.4Hz, 1H), 6.78 (d, 13C-NMR (CDCl3) δ: 167.4, 158.0, 149.8, 138.0, 127.6, 127.2,
J=9.1Hz, 1H), 3.65 (brs, 4H), 2.08–2.04 (m, 4H); 13C-NMR 127.1, 126.2, 121.7, 110.3, 46.0, 35.0, 25.8, 24.8, 14.9; MS: m/z
(CDCl3) δ: 165.6, 156.6, 150.7, 138.2, 137.6, 129.1, 127.8, 127.1, (EI-MS) 283 (M+); Purity: (HPLC) 89.57%.
127.0, 126.4, 124.3, 121.8, 120.1, 111.3, 46.9, 25.5; MS: m/z
2-(Piperidin-1-yl)-N-propylquinoline-6-carboxamide (13d):
Yield 38%; H-NMR (CDCl3) δ: 8.06 (d, J=2.0Hz, 1H), 7.88
1
(EI-MS) 317 (M+); Purity: (HPLC) 96.18%.
N-Benzyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12h): (d, J=9.2Hz, 1H), 7.84 (dd, J1=8.7Hz, J2=2.1Hz, 1H), 7.66
1
Yield 7%; H-NMR (CDCl3) δ: 8.11 (s, 1H), 7.87–7.85 (m, 2H), (d, J=8.3Hz, 1H), 7.01 (d, J=9.2Hz, 1H), 6.24 (brs, 1H),
7.76 (m, 1H), 7.40–7.29 (m, 5H), 6.74 (d, J=9.1Hz, 1H), 6.63 3.78–3.77 (m, 4H), 3.48–3.43 (m, 2H), 1.70–1.63 (m, 8H), 1.01
(brs, 1H), 4.67 (d, J=5.6Hz, 2H), 3.65 (brs, 4H), 2.07–2.04 (t, J=7.4Hz, 3H); 13C-NMR (CDCl3) δ: 167.4, 158.0, 149.8,
(m, 4H); 13C-NMR (MeOD) δ: 168.4, 139.0, 138.2, 136.9, 138.0, 127.7, 127.1, 126.8, 126.3, 121.8, 110.3, 46.1, 41.8, 25.8,
128.7, 127.9, 127.7, 127.6, 127.4, 127.1, 126.7, 124.2, 121.6, 24.8, 23.0, 11.5; MS: m/z (EI-MS) 297 (M+); Purity: (HPLC)
111.5, 43.2, 38.8, 25.0; MS: m/z (EI-MS) 331 (M+); Purity: 89.26%.
(HPLC) 86.39%.
2-(Piperidin-1-yl)-N,N-dipropylquinoline-6-carboxamide
Morpholino(2-(pyrrolidin-1-yl)quinolin-6-yl)methanone (13e): Yield 28%; 1H-NMR (CDCl3) δ: 7.83 (d, J=9.2Hz,
(12i): Yield 74%; 1H-NMR (CDCl3) δ: 7.82 (d, J=9.1Hz, 1H), 7.65 (d, J=8.4Hz, 1H), 7.60 (d, J=1.8Hz, 1H), 7.49 (dd,
1H), 7.69–7.68 (m, 2H), 7.51 (dd, J1=8.5Hz, J2=1.7Hz, 1H), J1=8.6Hz, J2=1.9Hz, 1H), 7.00 (d, J=9.2Hz, 1H), 3.74 (brs,
6.74 (d, J=9.0Hz, 1H), 3.70–3.62 (m, 12H), 2.05–2.02 (m, 4H), 3.46 (brs, 2H), 3.24 (brs, 2H), 1.69 (brs, 8H), 1.56 (brs,
4H); 13C-NMR (CDCl3) δ: 170.8, 156.2, 149.4, 137.3, 128.2, 2H), 0.98 (brs, 3H), 4.34 (brs, 3H), 0.72 (brs, 3H); 13C-NMR
127.6, 127.5, 125.9, 121.8, 111.1, 77.2, 67.0, 47.0, 25.5; MS: m/z (CDCl3) δ: 172.0, 149.8, 148.4, 137.5, 130.6, 127.8, 126.3,
(EI-MS) 311 (M+); Purity: (HPLC) 93.15%.
125.9, 122.0, 110.3, 46.1, 25.8, 24.8, 21.9, 20.8, 11.2; MS: m/z
(4-(4-Fluorophenyl)piperazin-1-yl)(2-(pyrrolidin-1-yl)- (EI-MS) 339 (M+); Purity: (HPLC) 92.84%.
1
quinolin-6-yl)methanone (12j): Yield 81%; H-NMR (CDCl3)
N-Isopropyl-2-(piperidin-1-yl)quinoline-6-carboxamide
δ: 7.84 (d, J=9.1Hz, 1H), 7.72 (d, J=1.8Hz, 1H), 7.70 (d, (13f): Yield 89%; 1H-NMR (CDCl3) δ: 8.04 (d, J=1.8Hz,
J=8.8Hz, 1H), 7.55 (dd, J1=8.6Hz, J2=1.9Hz, 1H), 7.00–6.95 1H), 7.86 (d, J=9.2Hz, 1H), 7.82 (dd, J1=8.7Hz, J2=2.0Hz,
(m, 2H), 6.92–6.87 (m, 2H), 6.76 (d, J=9.1Hz, 1H), 3.81 (m, 1H), 7.64 (d, J=8.7Hz, 1H), 6.99 (d, J=9.2Hz, 1H), 6.03 (d,
4H), 3.64 (m, 4H), 3.12 (m, 4H), 2.07–2.04 (m, 4H); 13C-NMR J=7.2Hz, 1H), 4.34–4.27 (m, 1H), 3.76–3.75 (m, 4H), 1.69
(CDCl3) δ: 170.8, 157.6 (J=238Hz), 156.3, 149.4, 147.7, 137.2, (brs, 6H), 1.28 (s, 3H), 1.27 (s, 3H); 13C-NMR (CDCl3) δ:
128.2, 127.8, 127.5, 126.0, 121.9, 118.6 (J=7.6Hz), 115.7 166.5, 157.9, 149.6, 138.0, 127.9, 127.2, 127.0, 126.2, 121.7,
(J=22.1Hz), 111.1, 50.8, 46.9, 45.8, 25.5; Purity: (HPLC) 110.3, 46.1, 41.9, 25.8, 24.8, 22.9; MS: m/z (EI-MS) 297 (M+);
96.24%.
(4-(2,4-Dimethylphenyl)piperazin-1-yl)(2-(pyrrolidin-1-yl)-
quinolin-6-yl)methanone (12k): Yield 23%; H-NMR (CDCl3) (13g): Yield 52%; H-NMR (CDCl3) δ: 8.02 (d, J=2.0Hz, 1H),
δ: 7.85 (d, J=9.1Hz, 1H), 7.73 (d, J=1.7Hz, 1H), 7.69 (d, 7.84 (d, J=9.3Hz, 1H), 7.79 (dd, J1=8.8Hz, J2=2.1Hz, 1H),
J=8.6Hz, 1H), 7.57 (dd, J1=8.6Hz, J2=1.9Hz, 1H), 7.02 (s, 6.65 (d, J=8.4Hz, 1H), 6.97 (d, J=9.2Hz, 1H), 6.41 (brs, 1H),
1H), 6.99 (d, J=8.2Hz, 1H), 6.92 (d, J=8.0Hz, 1H), 6.75 (d, 3.76–3.75 (m, 4H), 2.92 (octet, J=3.6Hz, 1H), 1.68–1.64 (m,
Purity: (HPLC) 96.56%.
N-Cyclopropyl-2-(piperidin-1-yl)quinoline-6-carboxamide
1
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June 2014
515
6H), 0.88–0.84 (m, 2H), 0.65–0.61 (m, 2H); 13C-NMR (CDCl3) 2.98 (t, J=5.0Hz, 4H); 13C-NMR (MeOD) δ: 170.7, 158.3,
δ: 168.8, 157.9, 149.8, 142.1, 138.1, 127.3, 127.1, 126.2, 121.7, 149.5, 138.4, 127.73, 127.70, 127.1, 125.8, 122.2, 110.3, 44.54,
110.4, 46.1, 25.8, 24.8, 23.2, 6.8; MS: m/z (EI-MS) 295 (M+); 44.47; MS: m/z (EI-MS) 256 (M+); Purity: (HPLC) 96.65%.
Purity: (HPLC) 98.09%.
N-Methyl-2-(4-methylpiperazin-1-yl)quinoline-6-
1
N-Phenyl-2-(piperidin-1-yl)quinoline-6-carboxamide (13h): carboxamide (14d): Yield 27%; H-NMR (CDCl3) δ: 8.07 (d,
1
Yield 45%; H-NMR (CDCl3) δ: 8.14 (d, J=1.9Hz, 1H), 7.93 J=1.8Hz, 1H), 7.91 (d, J=9.3Hz, 1H), 7.82 (dd, J1=8.7Hz,
(dd, J1=8.8Hz, J2=2.2Hz, 1H), 7.90 (d, J=10.2Hz, 2H), 7.67 J2=2.0Hz, 1H), 7.66 (d, J=8.7Hz, 1H), 6.99 (d, J=9.2Hz,
(d, J=7.9Hz, 2H), 7.38 (d, J=7.5Hz, 1H), 7.36 (d, J=6.7Hz, 1H), 6.17 (s, 1H), 3.82 (t, J=5.0Hz, 4H), 3.03 (d, J=4.9Hz,
1H), 7.13 (t, J=6.4Hz, 1H), 7.01 (d, J=9.3Hz, 1H), 3.74 (brs, 3H), 2.57 (t, J=5.0Hz, 4H), 2.37 (s, 3H); 13C-NMR (MeOD)
4H), 0.98 (brs, 6H); 13C-NMR (CDCl3) δ: 165.6, 158.1, 138.8, δ: 169.1, 158.0, 149.3, 138.4, 128.0, 127.3, 127.0, 126.0, 122.3,
138.2, 138.0, 129.1, 127.7, 127.4, 127.1, 126.5, 124.3, 121.8, 110.3, 54.1, 44.1, 43.7, 25.6; MS: m/z (EI-MS) 284 (M+); Pu-
120.2, 110.5, 46.1, 25.8, 24.8; MS: m/z (EI-MS) 331 (M+); Pu- rity: (HPLC) 95.49%.
rity: (HPLC) 95.67%.
N-Isopropyl-2-(4-methylpiperazin-1-yl)quinoline-6-
1
N-Benzyl-2-(piperidin-1-yl)quinoline-6-carboxamide (13i): carboxamide (14e): Yield 18%; H-NMR (MeOD) δ: 8.13 (d,
1
Yield 81%; H-NMR (CDCl3) δ: 8.08 (d, J=1.9Hz, 1H), 7.86 J=2.0Hz, 1H), 8.05 (d, J=9.2Hz, 1H), 7.92 (dd, J1=8.8Hz,
(d, J=8.1Hz, 1H), 7.85 (dd, J1=8.7Hz, J2=2.2Hz, 1H), 7.64 J2=2.1Hz, 1H), 7.63 (d, J=8.8Hz, 1H), 7.21 (d, J=9.2Hz, 1H),
(d, J=7.3Hz, 1H), 7.40–7.33 (m, 4H), 7.32–7.28 (m, 1H), 7.00 4.24–4.18 (m, 1H), 3.85 (brs, 4H), 2.77 (t, J=5.0Hz, 4H), 2.49
(d, J=9.3Hz, 1H), 6.43 (brs, 1H), 4.68 (d, J=5.6Hz, 2H), 3.76 (s, 3H), 1.25 (d, J=6.6Hz, 6H); 13C-NMR (MeOD) δ: 167.8,
(brs, 4H), 1.57 (brs, 6H); 13C-NMR (CDCl3) δ: 167.2, 143.3, 158.2, 149.3, 138.2, 128.2, 127.5, 127.0, 125.7, 122.1, 110.3,
143.1, 138.4, 138.2, 128.8, 128.6, 128.0, 127.6, 127.5, 127.3, 54.4, 44.7, 44.2, 41.8, 21.2; MS: m/z (EI-MS) 312 (M+); Purity:
126.3, 121.7, 110.4, 46.2, 44.2, 25.8, 24.8; MS: m/z (EI-MS) (HPLC) 89.05%.
345 (M+).
2-(4-Ethylpiperazin-1-yl)-N,N-dimethylquinoline-6-car-
Morpholino(2-(piperidin-1-yl)quinolin-6-yl)methanone boxamide (14f): Yield 28%; 1H-NMR (CDCl3) δ: 8.08 (d,
(13j): Yield 93%; 1H-NMR (CDCl3) δ: 7.83 (d, J=9.2Hz, J=2.0Hz, 1H), 7.91 (d, J=9.1Hz, 1H), 7.84 (dd, J1=8.8Hz,
1H), 7.67 (d, J=1.8Hz, 1H), 7.64 (d, J=8.6Hz, 1H), 7.51 (dd, J2=2.1Hz, 1H), 7.67 (d, J=8.8Hz, 1H), 7.00 (d, J=9.2Hz,
J1=8.6Hz, J2=2.0Hz, 1H), 6.99 (d, J=9.4Hz, 1H), 3.75–3.70 1H), 6.21 (d, J=4.0Hz, 1H), 3.82 (t, J=5.1Hz, 4H), 3.04 (d,
(m, 12H), 1.68–1.66 (m, 6H); 13C-NMR (CDCl3) δ: 170.7, J=4.9Hz, 3H), 2.60 (t, J=5.1Hz, 4H), 2.50 (q, J=7.2Hz, 2H),
157.8, 148.8, 137.6, 128.18, 128.15, 127.1, 126.3, 121.9, 110.4, 1.15 (t, J=7.2Hz, 3H); 13C-NMR (CDCl3) δ: 170.6, 168.0,
67.0, 48.0, 46.2, 43.6, 25.8, 24.8; MS: m/z (EI-MS) 325 (M+); 158.0, 138.2, 127.9, 127.1, 126.7, 124.8, 122.2, 110.1, 52.7, 52.4,
Purity: (HPLC) 97.55%.
44.8, 26.9, 11.9; MS: m/z (EI-MS) 312 (M+); Purity: (HPLC)
(4-Phenylpiperazin-1-yl)(2-(piperidin-1-yl)quinolin-6-yl)- 98.70%.
methanone (13k): Yield 23%; 1H-NMR (CDCl3) δ: 7.85 (d,
2-(4-Ethylpiperazin-1-yl)-N-isopropylquinoline-6-carbox-
J=9.2Hz, 1H), 7.71 (d, J=1.8Hz, 1H), 7.68 (d, J=8.4Hz, 1H), amide (14g): Yield 23%; 1H-NMR (MeOD) δ: 8.12 (d,
7.56 (dd, J1=8.6Hz, J2=1.9Hz, 1H), 7.29 (d, J=7.3Hz, 1H), J=2.0Hz, 1H), 8.01 (d, J=9.2Hz, 1H), 7.92 (dd, J1=8.8Hz,
7.27 (dd, J1=8.8Hz, J2=1.4Hz, 1H), 7.01 (d, J=9.2Hz, 1H), J2=2.1Hz, 1H), 7.61 (d, J=8.8Hz, 1H), 7.17 (d, J=9.2Hz, 1H),
6.94 (d, J=8.7Hz, 2H), 6.91 (t, J=8.4Hz, 1H), 3.77 (brs, 2H), 4.25–4.18 (m, 1H), 3.79 (t, J=5.1Hz, 4H), 2.59 (t, J=5.1Hz,
3.76 (s, 5H), 3.21 (brs, 4H), 1.70 (brs, 6H); 13C-NMR (CDCl3) 4H), 2.48 (q, J=7.2Hz, 2H), 1.25 (d, J=6.6Hz, 6H), 1.13
δ: 170.7, 158.0, 151.0, 137.5, 129.2, 128.8, 128.5, 128.2, 127.1, (t, J=7.2Hz, 3H); 13C-NMR (MeOD) δ: 167.8, 158.2, 149.3,
126.4, 122.0, 120.6, 116.7, 110.4, 49.8, 49.8, 46.1, 25.8, 24.8; 138.2, 128.2, 127.5, 127.0, 125.7, 122.1, 110.3, 52.3, 52.0, 44.2,
Purity: (HPLC) 95.74%.
41.8, 21.2, 10.4; MS: m/z (EI-MS) 326 (M+); Purity: (HPLC)
N-Ethyl-2-(piperazin-1-yl)quinoline-6-carboxamide
Yield 99%; H-NMR (CDCl3) δ: 8.08 (d, J=2.0Hz, 1H), 7.91
(14a): 94.04%.
1
2-(4-Ethylpiperazin-1-yl)-N-methylquinoline-6-carboxamide
(d, J=9.2Hz, 1H), 7.85 (dd, J1=8.7Hz, J2=2.1Hz, 1H), 7.67 (d, (14h): Yield 5%; 1H-NMR (MeOD) δ: 8.02 (d, J=9.2Hz,
J=8.7Hz, 1H), 6.99 (d, J=9.2Hz, 1H), 6.19 (brs, 1H), 3.76 (t, 1H), 7.74 (s, 1H), 7.66 (d, J=8.6Hz, 1H), 7.56 (dd, J1=8.6Hz,
J=5.0Hz, 4H), 3.56–3.49 (m, 2H), 3.01 (t, J=5.1Hz, 4H), 1.27 J2=1.8Hz, 1H), 7.20 (d, J=9.2Hz, 1H), 3.80 (t, J=4.9Hz, 4H),
(t, J=7.3Hz, 3H); 13C-NMR (CDCl3) δ: 167.2, 158.1, 149.6, 3.11 (brs, 3H), 3.07 (brs, 3H), 2.61 (t, J=5.0Hz, 4H), 2.50 (q,
138.1, 128.1, 127.13, 127.12, 126.6, 122.2, 110.1, 46.0, 45.9, J=7.2Hz, 2H), 1.15 (t, J=7.2Hz, 3H); 13C-NMR (MeOD) δ:
35.0, 15.0; MS: m/z (EI-MS) 284 (M+).
172.4, 158.1, 148.3, 137.8, 129.4, 127.8, 126.5, 125.9, 122.3,
2-(Piperazin-1-yl)-N,N-dipropylquinoline-6-carboxamide 110.5, 52.3, 52.0, 44.3, 38.9, 34.5, 10.4; MS: m/z (EI-MS) 298
(14b): Yield 54%; 1H-NMR (CDCl3) δ: 7.88 (d, J=9.2Hz, (M+); Purity: (HPLC) 94.59%.
1H), 7.67 (d, J=8.6Hz, 1H), 7.62 (d, J=1.7Hz, 1H), 7.50
2-Morpholinoquinoline-6-carboxamide (15a): Yield 97%;
(dd, J1=8.6Hz, J2=1.9Hz, 1H), 6.98 (d, J=9.2Hz, 1H), 3.76 1H-NMR (CDCl3) δ: 8.20 (s, 1H), 7.99 (d, J=9.3Hz, 1H), 7.93
(t, J=5.0Hz, 4H), 3.46 (brs, 2H), 3.21 (brs, 2H), 3.03 (t, (dd, J1=2.1Hz, J2=8.8Hz, 1H), 7.73 (d, J=8.8Hz, 1H), 7.03
J=5.0Hz, 4H), 1.68 (brs, 2H), 1.54 (brs, 2H), 0.98 (brs, 3H), (d, J=9.2Hz, 1H), 3.80 (dt, J1=4.6, J2=25.1Hz, 8H); MS: m/z
0.72 (brs, 3H); 13C-NMR (CDCl3) δ: 171.9, 157.8, 148.1, 137.7, (EI-MS) 257 (M+); Purity: (HPLC) 99.50%.
131.2, 127.9, 126.6, 125.9, 122.5, 110.0, 46.68, 45.7, 29.7, 20.8,
N-Methyl-2-morpholinoquinoline-6-carboxamide
(15b):
11.2; MS: m/z (EI-MS) 340 (M+); Purity: (HPLC) 92.26%.
Yield 53%; 1H-NMR (CDCl3) δ: 8.09 (s, 1H), 7.92 (d,
2-(Piperazin-1-yl)quinoline-6-carboxamide (14c): Yield J=9.2Hz, 1H), 7.85 (dd, J1=2.1, J2=8.7Hz, 1H), 7.68 (d,
34%; 1H-NMR (CDCl3) δ: 8.10 (d, J=1.9Hz, 1H), 7.90 (d, J=8.7Hz, 1H), 6.96 (d, J=9.2Hz, 1H), 6.30 (brs, 1H), 3.73
J=9.2Hz, 1H), 7.85 (dd, J1=8.7Hz, J2=2.0Hz, 1H), 7.65 (d, (dt, J1=4.8Hz, J2=37.0Hz, 8H), 3.03 (d, J=4.8Hz, 3H); MS:
J=8.7Hz, 1H), 6.98 (d, J=9.2Hz, 1H), 3.74 (t, J=5.0Hz, 4H), (EI-MS) m/z 271 (M+); Purity: (HPLC) 96.59%.

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Vol. 62, No. 6
N-Ethyl-2-morpholinoquinoline-6-carboxamide (15c): Yield 3H), 3.03 (d, J=4.8Hz, 3H); 13C-NMR (CDCl3) δ: 167.9, 163.5,
1
55%; H-NMR (CDCl3) δ: 8.10 (s, 1H), 7.92 (d, J=9.2Hz, 1H), 148.2, 139.3, 130.1, 127.5, 127.2, 127.1, 124.4, 114.1, 53.7, 27.0;
7.85 (dd, J1=2.1, J2=8.8Hz, 1H), 7.68 (d, J=8.6Hz, 1H), 6.96 MS: m/z (EI-MS) 216 (M+); Purity: (HPLC) 96.29%.
(d, J=9.2Hz, 1H), 6.24 (brs, 1H), 3.74 (dt, J1=4.7, J2=37.7Hz,
2-Methoxy-N,N-dimethylquinoline-6-carboxamide
(16b):
1
8H), 3.49 (m, 2H), 1.25 (t, J=7.3Hz, 3H); MS: (EI-MS) m/z Yield 46%; H-NMR (CDCl3) δ: 7.97 (d, J=8.8Hz, 1H), 7.85
285 (M+); Purity: (HPLC) 96.39%.
(d, J=8.6Hz, 1H), 7.81 (d, J=1.7Hz, 1H), 7.65 (dd, J=8.6Hz,
2-Morpholino-N-propylquinoline-6-carboxamide
(15d): J=1.9Hz, 1H), 6.93 (d, J=8.8Hz, 1H), 4.07 (s, 3H), 3.14 (brs,
Yield 32%; 1H-NMR (CDCl3) δ: 8.10 (s, 1H), 7.85 (dd, 3H), 3.03 (brs, 3H); 13C-NMR (CDCl3) δ: 171.3, 163.2, 147.1,
J1=2.1Hz, J2=8.7Hz, 1H), 7.95 (d, J=6.9Hz, 1H), 7.68 (d, 138.9, 131.8, 128.2, 127.3, 126.7, 124.4, 113.9, 53.5, 39.7, 35.5;
J=8.7Hz, 1H), 6.97 (d, J=9.2Hz, 1H), 6.24 (brs, 1H), 3.84 (t, Purity: (HPLC) 84.85%.
J=4.7Hz, 4H), 3.74 (t, J=4.8Hz, 4H), 3.43 (q, J=6.7Hz, 2H),
0.99 (t, J=7.4Hz, 3H), 1.62 (sextet, 2H); MS: (EI-MS) m/z 299 60%; 1H-NMR (CDCl3) δ: 8.17 (d, J=1.9Hz, 1H), 7.98 (d,
(M+); Purity: (HPLC) 96.14%.
J=8.9Hz, 1H), 7.95 (dd, J1=8.7Hz, J2=2.0Hz, 1H), 7.84 (d,
N-Ethyl-2-methoxyquinoline-6-carboxamide (16c): Yield
N-Isopropyl-2-morpholinoquinoline-6-carboxamide (15e): J=8.7Hz, 1H), 6.92 (d, J=8.8Hz, 1H), 6.37 (brs, 1H), 4.07
Yield 40%; 1H-NMR (CDCl3) δ: 8.09 (s, 1H), 7.95 (d, (s, 3H), 3.57–3.50 (m, 2H), 1.28 (t, J=7.3Hz, 3H); 13C-NMR
J=8.7Hz, 1H), 7.84 (dd, J=1.9, 8.7Hz, 1H), 7.70 (brs, 1H), (CDCl3) δ: 167.1, 163.5, 148.2, 139.3, 130.2, 127.5, 127.2, 127.1,
6.98 (d, J=9.2Hz, 1H), 5.97 (brs, 1H), 4.28 (septet, 1H), 3.76 124.4, 114.1, 53.6, 35.1, 14.9; MS: m/z (EI-MS) 230 (M+).
(m, 8H), 1.28 (d, J=6.6Hz, 6H); MS: (EI-MS) m/z 299 (M+);
Purity: (HPLC) 97.85%.
N-Isopropyl-2-methoxyquinoline-6-carboxamide
Yield 51%; H-NMR (CDCl3) δ: 8.15 (d, J=1.8Hz, 1H), 7.99
(16d):
1
N,N-Dimethyl-2-morpholinoquinoline-6-carboxamide (15f): (d, J=8.8Hz, 1H), 7.92 (dd, J1=8.7Hz, J2=2.0Hz, 1H), 7.84
1
Yield 63%; H-NMR (CDCl3) δ: 7.89 (d, J=9.1Hz, 1H), 7.71 (d, J=8.7Hz, 1H), 6.91 (d, J=8.8Hz, 1H), 6.08 (d, J=6.2Hz,
(s, 1H), 7.67 (d, J=8.6Hz, 1H), 7.56 (dd, J1=1.9Hz, J2=8.6Hz, 1H), 4.36–4.24 (m, 1H), 4.06 (s, 3H), 1.28 (d, J=6.6Hz, 6H);
1H), 6.95 (d, J=9.2Hz, 1H), 3.71 (dt, J1=4.8Hz, J2=44.4Hz, 13C-NMR (CDCl3) δ: 166.3, 163.5, 148.2, 139.3, 130.4, 127.5,
8H), 3.05 (brs, 6H); MS: (EI-MS) m/z 285 (M+); Purity: 127.2, 127.1, 124.4, 114.1, 53.6, 42.1, 22.9; MS: m/z (EI-MS)
(HPLC) 99.19%.
244 (M+); Purity: (HPLC) 99.76%.
2-Morpholino-N,N-dipropylquinoline-6-carboxamide (15g):
N-Cyclopropyl-2-methoxyquinoline-6-carboxamide
(16e):
Yield 32%; H-NMR (CDCl3) δ: 7.90 (d, J=9.1Hz, 1H), 7.68 Yield 56%; 1H-NMR (CDCl3) δ: 8.15 (s, 1H), 7.96 (d,
(d, J=8.5Hz, 1H), 7.65 (s, 1H), 7.51 (dd, J1=1.8Hz, J2=8.6Hz, J=8.8Hz, 1H), 7.92 (d, J=8.6Hz, 1H), 7.82 (d, J=8.6Hz, 1H),
1H), 6.97 (d, J=9.1Hz, 1H), 3.72 (dt, J=4.5, 35.4Hz, 8H), 3.47 6.91 (d, J=8.8Hz, 1H), 6.54 (brs, 1H), 2.96–2.92 (m, 1H),
(brs, 2H), 3.32 (brs, 2H), 1.66 (brs, 2H), 1.57 (brs, 2H), 0.99 0.90–0.85 (m, 2H), 0.68–0.64 (m, 2H); 13C-NMR (CDCl3) δ:
(brs, 3H), 0.71 (brs, 3H); MS: (EI-MS) m/z 341 (M+); Purity: 168.6, 163.5, 148.3, 139.3, 139.2, 129.8, 127.5, 127.1, 124.3,
1
(HPLC) 97.54%.
N-Cyclohexyl-2-morpholinoquinoline-6-carboxamide (15h): (HPLC) 96.73%.
Yield 89%; 1H-NMR (CDCl3) δ: 8.08 (s, 1H), 7.93 (d,
(2-Methoxyquinolin-6-yl)(pyrrolidin-1-yl)methanone (16f):
J=9.1Hz, 1H), 7.84 (dd, J1=2.1Hz, J2=8.8Hz, 1H), 7.68 (d, Yield 33%; H-NMR (CDCl3) δ: 7.98 (d, J=8.8Hz, 1H), 7.90
J=8.7Hz, 1H), 6.96 (d, J=9.2Hz, 1H), 6.06 (d, J=7.8Hz, 1H), (d, J=1.5Hz, 1H), 7.84 (d, J=8.6Hz, 1H), 7.76 (dd, J1=8.6Hz,
3.97 (m, 1H), 3.74 (dt, J1=4.8Hz, J2=38.4Hz, 8H), 2.04 (dd, J2=1.7Hz, 1H), 6.92 (d, J=8.8Hz, 1H), 4.07 (s, 3H), 3.68 (t,
J1=3.3Hz, J2=12.3Hz, 2H), 1.64 (dt, J1=3.6Hz, J2=13.4Hz, J=6.9Hz, 2H), 3.49 (t, J=6.5Hz, 2H), 2.00–1.95 (m, 2H),
4H), 1.46 (m, 2H), 1.30 (m, 2H); MS: (EI-MS) m/z 339 (M+); 1.91–1.87 (m, 2H); 13C-NMR (CDCl3) δ: 169.4, 163.3, 147.3,
114.1, 53.6, 23.3, 6.8; MS: m/z (EI-MS) 242 (M+); Purity:
1
Purity: (HPLC) 95.82%.
139.0, 132.7, 128.2, 127.2, 126.8, 124.4, 113.9, 53.6, 49.8,
(4-(4-Fluorophenyl)piperazin-1-yl)(2-morpholinoquinolin-6- 46.4, 26.5, 24.5; MS: m/z (EI-MS) 256 (M+); Purity: (HPLC)
1
yl)methanone (15i): Yield 77%; H-NMR (CDCl3) δ: 7.91 (d, 96.47%.
J=9.2Hz, 1H), 7.74 (s, 1H), 7.70 (d, J=8.6Hz, 1H), 7.57 (dd,
(2-Methoxyquinolin-6-yl)(piperidin-1-yl)methanone (16g):
1
J1=1,7Hz, J2=8.6Hz, 1H), 6.97 (d, J=9.5Hz, 2H), 6.95 (s, Yield 73%; H-NMR (CDCl3) δ: 7.97 (d, J=8.8Hz, 1H), 7.84
1H), 6.86 (q, J=4.5Hz, 2H), 3.83 (t, J=4.7Hz, 6H), 3.73 (t, (d, J=8.6Hz, 1H), 7.78 (d, J=1.8Hz, 1H), 7.62 (dd, J1=8.5Hz,
J=4.6Hz, 6H), 3.11 (brs, 4H); 13C-NMR (CDCl3) δ: 170.5, J2=1.8Hz, 1H), 6.92 (d, J=8.8Hz, 1H), 4.07 (s, 3H), 3.73 (brs,
158.8, 158.0, 156.5, 148.5, 147.6, 137.9, 129.3, 128.4, 127.1, 2H), 3.40 (brs, 2H), 1.69 (brs, 4H), 1.57 (brs, 2H); 13C-NMR
126.7, 122.5, 118.6, 115.8, 115.6, 110.0, 66.8, 50.8, 45.4; Purity: (CDCl3) δ: 170.1, 163.1, 147.1, 138.9, 132.0, 128.0, 127.4, 126.4,
(HPLC) 90.99%.
124.6, 113.9, 53.5, 48.9, 43.6, 26.3, 25.9, 24.6; MS: m/z (EI-MS)
(4-(2,4-Dimethylphenyl)piperazin-1-yl)(2-morpho- 270 (M+); Purity: (HPLC) 91.48%.
linoquinolin-6-yl)methanone (15j): Yield 95%; 1H-NMR
(2-Methoxyquinolin-6-yl)(4-methylpiperazin-1-yl)methanone
(CDCl3) δ: 7.92 (d, J=9.2Hz, 1H), 7.76 (s, 1H), 7.71 (d, J=7.7Hz, (16h): Yield 59%; 1H-NMR (CDCl3) δ: 7.94 (d, J=8.9Hz,
1H), 7.60 (dd, J1=1.6Hz, J2=8.6Hz, 1H), 6.98 (m, 3H), 6.91 1H), 7.82 (d, J=8.5Hz, 1H), 7.76 (d, J=1.5Hz, 1H), 7.59 (dd,
(d, J=8.0Hz, 1H), 3.75 (m, 12H), 2.90 (brs, 4H), 2.28 (d, J1=8.5Hz, J2=1.7Hz, 1H), 6.89 (d, J=8.8Hz, 1H), 4.03 (s,
J=7.1Hz, 6H); 13C-NMR (CDCl3) δ: 170.5, 157.9, 148.5, 137.9, 3H), 3.76 (brs, 2H), 3.53 (brs, 2H), 2.40 (brs, 4H), 2.29 (s,
133.3, 132.7, 131.3, 129.7, 128.5, 127.2, 127.0, 122.5, 119.2, 3H); 13C-NMR (CDCl3) δ: 170.1, 163.2, 147.1, 138.8, 131.2,
109.9, 66.8, 52.26, 45.4, 20.7, 17.7; Purity: (HPLC) 99.52%.
128.0, 127.4, 126.8, 124.5, 114.0, 55.0, 53.5, 47.8, 46.0, 42.2;
2-Methoxy-N-methylquinoline-6-carboxamide (16a): Yield MS: m/z (EI-MS) 285 (M+).
55%; 1H-NMR (CDCl3) δ: 8.16 (d, J=1.8Hz, 1H), 7.96 (d,
Procedures for Preparing Compounds 12b and 12c 2-
J=8.6Hz, 1H), 7.93 (dd, J1=8.5Hz, J2=2.1Hz, 1H), 7.82 (d, (Pyrrolidin-1-yl)quinoline-6-carbonitrile (17): A mixture of
J=8.7Hz, 1H), 6.90 (d, J=8.8Hz, 1H), 6.47 (brs, 1H), 4.06 (s, 6-bromoquinoline 10a (1.26g, 4.55mmol) and tetrakis(triphen-

June 2014
517
ylphosphine)palladium(0) (527mg, 0.456mmol) and copper(I) mented with 10% (v/v) fetal bovine serum, penicillin (100U/
cyanide (816mg, 9.11mmol) in DMF was stirred for 48h at mL), streptomycin (100µg/mL), and 1% (v/v) Chem-3 growth
120°C on an oil bath. After the reaction was finished (moni- supplement at 37°C in a humid atmosphere of 5% CO2 and
tored by TLC), the mixture was filtered through Celite. The 95% air.
filtrate was diluted with water and extracted with EtOAc. The
For calcium assay, cells were harvested and dispensed into
combined organic layer was dried over MgSO4, filtered, and 96-well black wall clear bottom plates at a density of 100000
concentrated under reduced pressure. The crude product was cells per a well. After 1h of stabilization, cells were treated
purified by column chromatography on silica gel (EtOAc–hex- with Calcium-5 assay reagent, which is prepared by manu-
ane 1:1) to afford the title compounds 17 (718mg, 93%) as a facturer’s instruction (Molecular Devices Corporation, Cali-
1
yellow solid; H-NMR (CDCl3) δ: 7.87 (d, J=1.2Hz, 1H), 7.78 fornia). During fluorescence-based FDSS6000 assay, mGluR1
(d, J=9.1Hz, 1H), 7.66 (d, J=8.6Hz, 1H), 7.60 (dd, J1=8.7Hz, was activated using a high concentration of L-glutamate
J2=1.6Hz, 1H), 6.76 (d, J=9.1Hz, 1H), 3.62 (brs, 4H), 2.05 (30 µM) in HBSS, and various concentrations of potential an-
(brs, 4H); 13C-NMR (DMSO-d6) δ: 156.9, 150.5, 137.4, 134.2, tagonists were treated to cells 75s before mGluR activation.
131.0, 127.0, 122.3, 120.2, 112.8, 102.6, 47.1, 25.4; MS: m/z All data were collected and analyzed using FDSS6000 and
(EI-MS) 223 (M+).
related software (Hamamatsu, Japan).
2-(Pyrrolidin-1-yl)quinoline-6-carboxamide (18): A mixture
In Vivo Behavioral Test Two behavioral tests (mechani-
of 6-cyanoquinoline 17 (83.8mg, 0.345mmol) and potassium cal allodynia and cold allodynia) were conducted for rats at 1d
hydroxide (70mg, 1.25mmol) in tert-butanol (5mL) was pre- prior to surgery and 14d after surgery. After the postoperative
pared. After the reaction mixture was stirred at 100°C for 2h, behavioral test, the animals were treated orally with 100mg/
it was quenched by excessive water and extracted with EtOAc kg compound 13c or gabapentin. The tests were re-evaluated
(3×20mL). The organic layer was separated, dried over at 1h, 3h, and 5h after administration.
MgSO4, and concentrated under reduced pressure to give the
Mechanical Allodynia: Testing was performed according
title compound 18 (80.7mg, 97%) as a yellow solid, which was to methods described previously.25) Rats were acclimated in
1
used in the next step without further purification; H-NMR a transparent plastic boxes permitting freedom of movement
(DMSO-d6) δ: 8.20 (d, J=1.9Hz, 1H), 7.99 (d, J=9.1Hz, with a wire mesh floor to allow access to the planter surface
1H), 7.92 (dd, J1=8.8Hz, J2=2.9Hz, 2H), 7.48 (d, J=8.7Hz, of the hind paws. A von Frey filament (Stoelting, Wood Dale,
1H), 7.22 (brs, 4H), 6.99 (d, J=9.1Hz, 1H), 3.38 (brs, 4H), IL, U.S.A.) was applied 5 times (once every 3–4s) to hind
1.97–1.95 (m, 4H); 13C-NMR (DMSO-d6) δ: 168.3, 156.5, paw. Von Frey filaments were used to assess the 50% me-
150.1, 138.1, 128.5, 128.4, 127.0, 125.6, 121.6, 111.8, 47.0, 25.5; chanical threshold for paw withdrawal. The 50% withdrawal
MS: m/z (EI-MS) 241 (M+); Purity: (HPLC) 97.68%.
threshold was determined by using the up-down method and
N-Methyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide (12b) formula given by Dixon26): 50% threshold=10(X+kd)/104,
and N,N-Dimethyl-2-(pyrrolidin-1-yl)quinoline-6-carboxamide where X is the value of the final von Frey hair used (in log
(12c): To a solution of carboxamide 18 (28.1mg, 117µmol) in units), k is the tabular value for the pattern of positive/negative
benzene was added 50% aq.NaOH (0.12mL) and tetrabutyl responses modified from Dixon26), and d is the mean differ-
ammonium hydrogen sulfate (3.97mg, 11.7µmol). After the re- ence between stimuli in log units (0.17).
action mixture was stirred at 100°C for 5min, methyl bromde
Cold Allodynia: To quantify cold sensitivity of the paw,
(3.0mL, 54.7mmol) was added. The resulting mixture was brisk paw withdrawal in response to acetone application was
stirred at 100°C for additional 2.5h and quenched with water. measured as described previously.27) The rat was placed under
The organic layer was separated and the aqueous layer was a transparent plastic box on a metal mesh floor and acetone
extracted with ethyl acetate (3×15mL). The combined organic was applied to the plantar surface of the hind paw. To do this,
layer was dried over MgSO4 and concentrated under reduced an acetone bubble was formed at the end of a small piece
pressure. The crude product was purified by column chro- of polyethylene tubing which was connected to a syringe.
matography on silica gel (CH2Cl2–MeOH 20:1) to afford the The bubble was then gently touched to the heel. The acetone
title compounds 12b (5.3mg, 18%) as a white solid and 12c quickly spread over the proximal half of the plantar surface of
1
(22.3mg, 71%) as a white solid; 12b: H-NMR (CDCl3) δ: 8.06 the hind paw. The acetone was applied 5 times to hind paw
(d, J=2.0Hz, 1H), 7.85 (d, J=9.1Hz, 1H), 7.81 (dd, J1=8.8Hz, at 2min interval. The frequency of paw withdrawal was ex-
J2=2.1Hz, 1H), 7.72 (d, J=8.6Hz, 1H), 6.72 (d, J=9.1Hz, pressed as a percentage [(No. of trials accompanied by brisk
1H), 6.31 (brs, 1H), 3.63 (brs, 4H), 3.02 (d, J=4.8Hz, 3H), foot withdrawal/total No. of trials)×l00].
2.05–2.00 (m, 4H); 13C-NMR (MeOD) δ: 169.1, 156.4, 149.5,
138.0, 127.4, 127.3, 126.8, 124.4, 121.6, 111.4, 29.3, 25.5, 25.0;
Acknowledgments This research was supported by the
Purity: (HPLC) 95.47%. 12c: 1H-NMR (CDCl3) δ: 7.79 (d, Korea Institute of Science and Technology (KIST, 2E23870,
J=9.1Hz, 1H), 7.66 (d, J=1.7Hz, 1H), 7.64 (s, 1H), 7.52 (dd, 2E24183, 2E23770) and by a Grant of the Korea Health tech-
J1=8.6Hz, J2=1.8Hz, 1H), 6.70 (d, J=9.0Hz, 1H), 3.59 (brs, nology R&D Project, the Ministry of Health and Welfare,
4H), 3.05 (brs, 6H), 2.00 (t, J=6.5Hz, 4H); 13C-NMR (CDCl3) Republic of Korea (HI11C0998).
δ: 171.8, 156.1, 149.0, 137.3, 128.7, 128.4, 127.2, 125.7, 121.7,
111.0, 46.9, 40.0, 35.7, 25.5; MS: m/z (EI-MS) 269 (M+); Pu-
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