Molecular design, chemical synthesis, and biological evaluation of '4-1' pentacyclic aryl/heteroaryl-imidazonaphthalimides

Article abstract of DOI:10.1016/j.bmc.2007.05.032

A novel series of '4-1' pentacyclic naphthalimides, where the chromophore consists of a naphthalimide moiety, fused to an imidazole ring containing an unfused aryl or heteroaryl ring, were synthesized and evaluated for in vitro antitumor activity. In gene

Full text of DOI:10.1016/j.bmc.2007.05.032

Bioorganic & Medicinal Chemistry 15 (2007) 5114–5121
Molecular design, chemical synthesis, and biological evaluation
of ‘4-1’ pentacyclic aryl/heteroaryl-imidazonaphthalimides
a
a,
b
a,c,
*
*
Feng Li, Jingnan Cui, Lianying Guo, Xuhong Qian,
a
a
a
Weimin Ren, Kewei Wang and Fengyu Liu
a
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, China
b
Institute for Cancer Biotherapy, Dalian Medical University, Dalian 116027, China
Shanghai Key Laboratory of Chemical Biology, East China University of Science and Technology, Shanghai 200237, China
c
Received 15 April 2007; revised 10 May 2007; accepted 11 May 2007
Available online 17 May 2007
Abstract—A novel series of ‘4-1’ pentacyclic naphthalimides, where the chromophore consists of a naphthalimide moiety, fused to
an imidazole ring containing an unfused aryl or heteroaryl ring, were synthesized and evaluated for in vitro antitumor activity. In
general, the new derivatives showed an improved cytotoxic activity over amonafide. DNA binding experiments supported that this
class of compounds behaves as effective DNA-intercalating agents.
ꢀ
2007 Elsevier Ltd. All rights reserved.
1. Introduction
N
O
O
H
N
H
N
DNA-intercalating agents, containing a planar chromo-
phore with two to four fused aromatic rings, represent a
O
N
O
N
N
1
large family of antitumor drugs. They exhibit cytostatic
activity through DNA intercalation, which causes enzy-
matic blockade and reading errors during the replication
O
O
NH2
2
Amonafide
Elinafide
process. Naphthalimides are typically DNA-intercalat-
3
ing agents and two lead compounds of naphthalimides,
4
Figure 1. The lead compounds of naphthalimides: Amonafide (left)
and Elinafide (right).
5
amonafide and elinafide, were selected for phase I and
II clinical trials (Fig. 1).
Over the past decade, a great deal of work has been de-
voted toward the modification of the chromophore of
naphthalimide in order to enhance the potency of naph-
cellular cytotoxic activity over amonafide. More
recently, another series of naphthalimides, where an
unfused benzene or furan ring was introduced, was
reported by the same research group and exhibited
extraordinary cytotoxicity and growth delays for cancer
6
–8
thalimides.
Recently, increasing attention has been
focused on the design of new naphthalimides where het-
erocyclic systems have been ‘fused’ to the naphthalimide
7
d
cell lines in vitro.
6
e,7,8
chromophore.
Brana and co-workers synthesized
several series of naphthalimides, where the chromo-
phore consisted of a naphthalimide moiety, fused to
an imidazole, pyrazine, furan, or thiophene ring,
and some of them showed significant improvement in
Our research group also developed several series of
naphthalimides with extended heteroaromatic systems
as effective artificial photonucleases and antitumor
7
a
7b
7c
8
agents. In an attempt to further explore structurally
novel DNA-intercalating agents, we herein wish to
report the design, synthesis, and biological evaluation
of a series of ‘4-1’ pentacyclic naphthalimides, where
the chromophore consists of a naphthalimide moiety,
fused to an imidazole ring containing an unfused aryl
or heteroaryl ring (Fig. 2). The introduction of a fused
Keywords: Aryl/heteroaryl-imidazonaphthalimides; ‘4-1’ Pentacyclic
DNA-intercalating agents.
*
Corresponding authors. Tel.: +86 411 88993872; fax: +86 411
3673488 (J.C.); e-mail addresses: jncui@dlut.edu.cn; xhqian@ecust.
edu.cn
8
0
968-0896/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2007.05.032

F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
5115
N
pounds and could be prepared using the method of Bra-
7
na and co-workers.
N
b
O
N
O
6
6
6
6
6
6
6
6
6
6
a: R1 = R2 = H
O
N
O
An alternatively shorter route for the synthesis of
diamine 4 was explored and is outlined in Scheme 1.
Nitration of commercially available 4-bromo-naphtha-
lene-1,8-dicarboxylic anhydride 1 and treatment of the
resulting 2 with sodium azide in DMF at 100 ꢁC gave
the compound 3, which was further reduced by hydroge-
nation over Pd/C to afford the desired diamine 4 with
79% overal yield. The last two steps in new three-step
procedure were achieved in nearly quantitative yield
without any purification. To the best of our knowledge,
this is the first example of the preparation of diamine by
catalytic hydrogenation of nitro and azide groups at the
same time.
b: R1 = H, R2 = Cl
c: R1 = H, R2 = CF3
d: R1 = H, R2 = Me
e: R1 = H, R2 = N(Me)2
f: R1 = H, R2 = OH
g: R1 = H, R2 = OMe
h: R1 = H, R2 = OEt
i: R1 = OH, R2 = OMe
j: R1 = R2 = OMe
6k: X = O
l: X = S
6
NH
NH
N
N
X
R1
R2
N
N
O
N
O
O
N
O
6m: Y = O
6
6
6
q: W = Z = H, K = N
r: K = Z = H, W = N
s: K = W = H, Z = N
6
6
6
n: Y =S
o: Y = N, R3 = H
p: Y = N, R3 = Me
NH
The next step in the synthesis involved the formation of
aryl/heteroaryl-imidazole ring system. Condensation of
diamine 4 and aldehydes using sodium bisulfite as the
oxidant in presence of DMF at 100 ꢁC gave the corre-
sponding aryl/heteroaryl-naphthalene-1,8-dicarboxylic
anhydrides 5a–s with 67–79% yields.
NH
N
N
R3
K
Z
Y
W
Figure 2. Molecular structures of aryl/heteroaryl-imidazonaphthalimides.
In the final step, aryl/heteroaryl-imidazonaphthalimides
imidazole ring can lead to the formation of a larger aro-
matic system and consequently to a higher affinity for
the DNA molecular, and must have an effect on the elec-
6a–s were obtained by treatment of the corresponding
anhydrides 5a–s with N,N-dimethylethane-1,2-diamine
in ethanol at reflux temperature with 70–77% yields.
7
a
trostatic properties of the chromophore. The conform-
ationally flexible, unfused aryl or heteroaryl ring not
only further extends the conjugated system, but also
2.2. Biological evaluation
9
was expected to amplify the antitumor activity and to
be relatively nontoxic to human cells, as has been shown
The aryl/heteroaryl-imidazonaphthalimides were evalu-
ated for in vitro cytotoxicity against P388 (murine leuke-
mia), A-549 (human lung cancer), SMMC-7721 (human
hepatoma), HeLa (human cervical carcinoma), and HL-
1
0
for other unfused aromatic compounds.
6
0 (human acute promyelocytic leukemia) cell lines. The
2
. Results and discussion
results are summarized in Table 1 and compared with
the activities of amonafide. In general, the new deriva-
tives showed an improved cytotoxic activity over
amonafide. Among them, arylimidazonaphthalimides
2
.1. Chemistry
,4-Diamino-naphthalene-1,8-dicarboxylic anhydride was
the key intermediate for the synthesis of targeted com-
3
6
g and 6j, bearing a methoxyl group and two methoxyl
groups, were found to be the most effective compounds
against HeLa and SMMC-7721, with IC50 values of
0
O
O
O
O
O
O
O
O
O
.21 lM and 0.22 lM, respectively. Heteroaryl-imidazo-
i
ii
naphthalimides 6l, 6p, and 6q exhibit the highest activi-
ties against P388, A-549, and HL-60, presenting values
that are 28.5-fold, 31.7-fold, and 5.4-fold lower than
the values found for amonafide under the same experi-
mental conditions, respectively.
NO2
NO2
Br
N
Br
N3
1
2
3
iii
2.3. DNA binding properties
O
N
O
O
O
O
O
O
O
To evaluate the DNA binding properties of aryl/het-
eroaryl-imidazonaphthalimides, the melting tempera-
ture (T ) measurements were performed with calf
v
iv
m
NH2
NH
Ar (Hete)
NH
thymus DNA (CT-DNA). It is known that thermal
denaturation profiles provide the simplest means for
detecting binding and asserting relative binding
strength. As shown in Table 1, binding of any of
the compounds tested resulted in Tm being raised,
indicative of stabilization of DNA double helix. Obvi-
ously, the stabilization of DNA double helix may be
contributing to the inhibition of DNA replication,
N
N
NH2
Ar (Hete)
6
5
4
Scheme 1. Reagents and conditions: (i) HNO
ii) NaN , H
O, DMF, 100 ꢁC, 97%; (iii) Pd/C, H
Ar/heteroaryl-CHO, NaHSO
DMF, 100 ꢁC, 67–79%; (v)
NH (CH N(CH /C OH, refluxed, 70–77%.
3
, AcOH, 0–5 ꢁC, 85%;
(
3
2
2
, DMF, rt, 96%; (iv)
3
,
2
2
)
2
3
)
2
2 5
H

5116
F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
Table 1. Growth-inhibitory properties for aryl/heteroaryl-imidazonaphthalimides
a
b
c
d
e
f
m
Entry
Compound
Ar/heteroaryl
Phenyl
P388
A-549
SMMC-7721
Hela
HL-60
DT
(ꢁC)
IC50 (lM)
IC50 (lM)
IC50 (lM)
IC50 (lM)
IC50 (lM)
1
2
3
4
5
6
7
8
9
6a
6b
0.86
0.95
0.71
5.50
1.68
1.10
3.72
2.48
1.92
1.07
0.71
0.16
0.65
4.15
0.21
0.21
0.77
2.31
5.65
4.56
7.54
9.13
26.2
5.53
8.50
17.8
2.16
14.7
5.08
0.60
7.48
8.59
7.23
6.67
0.45
0.41
9.33
9.97
60.9
13.0
3.36
0.27
1.63
0.58
2.86
>100
1.35
1.02
>100
0.22
0.88
0.93
1.30
3.27
2.99
2.90
3.36
1.29
1.76
4.15
0.40
0.28
0.40
0.32
0.25
13.1
0.21
0.52
>100
5.19
13.9
0.54
1.73
1.34
3.30
7.98
2.71
1.16
5.35
1.40
0.86
3.28
4.90
1.04
1.08
23.0
0.46
4.58
50.5
10.4
5.21
0.58
6.24
0.59
3.03
3.66
0.30
1.33
2.66
1.63
7.2
7.1
4.8
6.6
0
4 -Cl-phenyl
0
0
0
0
0
0
6c
4 -CF
3
-phenyl
6d
4 -Me-phenyl
6e
4 -N( Me) -phenyl
4 -OH-phenyl
2
12.1
6.3
7.0
10.5
7.8
13.3
6.7
8.4
6.8
6.9
5.7
6.2
3.8
4.0
4.8
6f
6g
4 -OMe-phenyl
4 -OEt-phenyl
6h
6i
0
0
3 -OMe-4 -OH-phenyl
0
0
10
11
12
13
14
15
16
17
18
19
20
6j
6k
3 ,4 -(OMe)
Furan-3-yl
2
-phenyl
6l
6m
Thiophen-3-yl
Furan-2-yl
6n
6o
Thiophen-2-yl
1H-pyrrol-2-yl
1-Me-1H-pyrrol-2-yl
Pyridin-2-yl
6p
6q
6r
Pyridin-3-yl
Pyridin-4-yl
6s
Amonafide
g
NT
a
b
c
d
e
f
Murine leukemia cell line.
Human lung cancer cell line.
Human hepatoma cell line.
Human cervical carcinoma cell line.
Human acute promyelocytic leukemia cell line.
complex
m
DNA
m
Variation in melting temperature ðDTm ¼ T
ꢀ T
Þ. T
m
measurements were performed in BPE buffer, pH 7.1 (6 mM Na
2
HPO
4
, 2 mM
2 4 m
NaH PO , 1 mM EDTA), using 10 lM compound and 20 lM calf thymus DNA (CT-DNA) at 260 nm with a heating rate of 1 ꢁC/min T of CT-
DNA = 69.0 ꢁC.
NT, not test.
g
thus resulting in antitumor activity. In some cases,
the compounds that were found to bind strongly to
DNA correspond to the most cytotoxic agent. For
example, compounds 6e, 6l, and 6j, which are highly
cytotoxic, gave DTm values of >8 ꢁC with CT-DNA.
However, there is no direct relationship between
DNA binding and cytotoxicity. It indicated that
DNA is a potential, but not a unique, target for anti-
tumor activity.
1.08
.07
1.06
.05
1.04
1
1
1.03
1.02
1.01
1.00
The DNA binding properties of compound 6a as a
model of aryl-imidazonaphthalimide and 6m as a
model of heteroaryl-imidazonaphthalimide were fur-
ther studied by viscosimetric titration and UV–visible
spectrometry with CT-DNA. Viscosity measurement
is regarded as the least ambiguous and the most crit-
ical tests of a binding model in solution in the absence
of X-ray and NMR structural data. A classical inter-
calation model demands that the DNA helix lengthens
as base pairs are separated to accommodate the
bound ligand, leading to the increase of DNA viscos-
0.00
0.02
0.04
0.06
0.08
0.10
[Compound]/[DNA]
Figure 3. Effect of increasing amounts of compounds 6a (black curve)
and 6m (red curve) on the relative viscosities of CT DNA at 25
(
±0.1) ꢁC. [DNA] = 20 lM. g is the viscosity of DNA in the presence of
compound and g
0
is the viscosity of DNA in the absence of compound.
1
1
ity. The viscosity of DNA increases steadily with
increasing concentration of the compounds, and the
experiment results suggested that compounds bind to
DNA through a classical intercalation mode (Fig. 3).
Addition of CT-DNA caused the absorptions for free
3. Conclusions
In summary, we developed a novel series of ‘4-1’ penta-
cyclic DNA-intercalating agents based on an aryl/het-
eroaryl-imidazonaphthalimide system. The present
work also opens up new perspectives for further devel-
opment of DNA-targeted antitumor agents. Further
studies to carry out structure–activity relationships
(SARs) for cellular growth inhibition and stabilization
of ternary complex DNA-naphthalimide-Topo II as well
6
a at 396 nm and 6m at 408 nm (kmax) to decrease in
intensity, and exhibited 8 nm and 5 nm red shifts,
respectively (Fig. 4). The well-defined spectral changes
also further confirmed that they behave as DNA-inter-
1
2
calating agents.

F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
5117
0
0
0
0
0
0
0
0
0
0
0
.20
.18
.16
.14
.12
.10
.08
.06
.04
.02
.00
dicarboxylic anhydride 1 (15.0 g, 54.3 mmol) in AcOH
(130 ml) at 0–5 ꢁC was added slowly a mixture of 65%
HNO (5.8 g, 59.7 mmol), keeping the temperature at
3
0–5 ꢁC. The mixture was allowed to stand at room
temperature for 2 h, and the solution was poured into
water and ice. The precipitate formed was filtered,
washed with water, and dried. Recrystallization from
AcOH gave 2 (14.8 g, 85%) as a yellow solid, mp
1
3
1
2
33–234 ꢁC (lit. 231–232 ꢁC); H NMR (400 MHz,
DMSO-d ) d 8.92 (d, J = 8.4, 1H, ArH), 8.82 (m, 2H,
6
ArH), 8.16 (t, J = 8.0, 1H, ArH), 8.06 (t, J = 8.8,
1H, ArH).
350
400
450
4.1.2. 3-Azido-4-nitro-naphthalene-1,8-dicarboxylic anhy-
dride (3). To a suspension of 2 (10.0 g, 31.2 mmol) in
DMF (30 ml) was added a suspension of sodium azide
(2.2 g, 34.3 mmol) in water (0.5 ml). The mixture was
heated to 100 ꢁC for 10 min and then poured into
water and ice. The precipitate formed was filtered,
washed with water, and dried. Compound 3 (8.6 g,
Wavelength (nm)
0
0
0
0
0
0
0
0
.35
.30
.25
.20
.15
.10
.05
.00
9
2
7%) was obtained as a yellow solid, mp 217–
1
18 ꢁC; H NMR (400 MHz, DMSO-d ) d 8.90 (d,
6
J = 8.8, 1H, ArH), 8.86 (s, 1H, ArH), 8.69 (d,
J = 8.8, 1H, ArH), 8.06 (t, J = 8.8, 1H, ArH);
1
3
C
NMR (100 MHz, DMSO-d ) d 159.9, 159.1, 139.7,
6
137.9, 135.3, 131.7, 131.4, 129.3, 127.4, 126.2, 119.8,
1
ꢀ
1
15.7; IR (KBr, cm ) 1770.1, 1740.5; HRMS-EI
(
70 eV) m/z calcd for C H N O 284.0182, found
5
1
2
4
2
3
50
400
450
284.0187.
Wavelength (nm)
Figure 4. Absorption spectra of compounds 6a (top) and 6m (bottom)
in Tris–HCl buffer upon addition of CT DNA with subtraction of the
DNA absorbance ([Compound] = 20 lM; [DNA]/[Compound] = 0, 2,
4
.1.3. 3,4-Diamino-naphthalene-1,8-dicarboxylic anhydride
(4). A mixture of 3 (7.0 g, 24.6 mmol) and 10% Pd/C
(300 mg) in DMF (100 ml) was shaken in a Parr hydro-
4, 6, 8).
genator under hydrogen at 50 PSI pressure for 24 h. The
catalyst was then filtered off and washed with DMF. The
filtrate was concentrated, and water was added. The
precipitate was then filtered, washed with water, and
as to select a part of compounds for in vivo antitumoral
assays are currently under way.
dried. Compound 4 (5.4 g, 96%) was obtained as a
brown solid, mp > 300 ꢁC;
1
H NMR (400 MHz,
DMSO-d ) d 8.78 (d, J = 8.4, 1H), 8.43 (d, J = 6.8,
4. Experimental
6
1H, ArH), 8.28 (s, 1H, ArH), 7.76 (dd, J = 8.4, 6.8,
1H, ArH).
4
.1. Chemistry
Melting points were determined by a X-6 micro-melting
point apparatus and are uncorrected. Infrared (IR) spec-
tra were measured on a Nicolet 20DXB FR-I infrared
spectrometer, with samples analyzed as KBr disks.
High-resolution mass spectra (HRMS) were obtained
on a HPLC-Q-Tof MS (Micro) spectrometer. The purity
of compounds was checked by ascending TLC on
Merck’s silica gel plates (0.25 mm) with fluorescent bak-
ing. NMR measurements (data reported in ppm) were
performed on a Varian INOVA spectrometer operating
at 400 MHz or a AVANCE spectrometer operating at
4.2. General procedure for the preparation of anhydride
and the corresponding naphthalimide
A mixture of diamine 4, aldehyde and NaHSO in DMF
3
was heated at 100 ꢁC until the reaction was completed
(TLC). After the solution was cooled, water was added
and then the precipitate was filtered. Recrystallization
from DMF gave the corresponding anhydride as a
solid.
A suspension of the corresponding anhydride was trea-
ted with an excess of the N,N-dimethylethane-1,2-dia-
mine in absolute EtOH. The mixture was heated at
reflux temperature until the reaction was completed
(TLC). After removal of organic solvent under reduced
pressure, the crude mixture was purified by flash chro-
matography (silica gel, CHCl /CH OH, 10:1, v/v) to af-
5
00 MHz, respectively. Chemical shifts d are reported
in ppm downfield from tetramethylsilane, J values are
in hertz, and the splitting patterns were designated as
follows: s, singlet; d, doublet; t, triplet; q, quartet; m,
multiplet; b, broad. UV spectra were recorded on HP
8
453 UV–visible spectrophotometer.
3
3
ford the pure naphthalimide. In all cases, no peak of
impurity was detected by H NMR spectrum of the
products.
1
4.1.1. 3-Bromo-4-nitro-naphthalene-1,8-dicarboxylic anhy-
dride (2). To a suspension of 4-bromo-naphthalene-1,8-

5118
F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
1
4.2.1. 5-[2-(Dimethylamino)ethyl]-9-phenyl-5,8-dihydro-
benz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6a). From
H NMR (400 MHz, DMSO-d ) d 8.84 (d, J = 8.8, 1H,
6
ArH), 8.58 (s, 1H, ArH), 8.40 (d, J = 7.2, 1H, ArH),
4
1
(200 mg, 0.88 mmol) and benzaldehyde (116 mg,
.10 mmol), and NaHSO3 (137 mg, 1.32 mmol) in
8.15 (d, J = 8.0, 2H, ArH), 7.88 (dd, J = 8.8, 7.2,
1H, ArH), 7.41 (d, J = 8.0, 2H, ArH), 4.15 (t, J = 6.4,
2H, CH NCO), 2.54 (t, J = 6.4, 2H, CH N), 2.23
DMF (15 ml) yielded 5a (212 mg, 77%) as a yellow solid,
mp > 300 ꢁC. From 5a (150 mg, 0.48 mmol) and N,N-
dimethylethane-1,2-diamine (103 mg, 1.17 mmol) in
absolute EtOH (15 ml) yielded 6a (136 mg, 74%) as a
yellow solid, mp 275–276 ꢁC; H NMR (400 MHz,
DMSO-d ) d 8.86 (d, J = 8.0, 1H, ArH), 8.61 (s, 1H,
ArH), 8.42 (d, J = 6.8, 1H, ArH), 8.28 (d, J = 6.8,
2H, ArH), 7.89 (dd, J = 8.0, 6.8, 1H, ArH), 7.61 (d,
J = 6.8, 2H, ArH), 7.60 (m, 1H, ArH), 4.15 (t, J = 6.4,
2
6
2
2
ꢀ
1
(s, 6H, 2· CH ); IR (KBr, cm ), 3294.0, 1692.7,
3
1638.6; HRMS-EI (70 eV) m/z calcd for C H N O
2
2
4
22
4
398.1743, found 398.1745.
1
4.2.5. 5-[2-(Dimethylamino)ethyl]-9-[4-(dimethylamino)
phenyl]-5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-
dione (6e). From 4 (200 mg, 0.88 mmol) and 4-dimethyl-
6
amino-benzaldehyde
(144 mg,
0.97 mmol),
and
NaHSO (137 mg, 1.32 mmol) in DMF (15 ml) yielded
H, CH NCO), 2.54 (t, J = 6.4, 2H, CH N), 2.23 (s,
2
2
3
ꢀ
1
H, 2· CH ); IR (KBr, cm ) 3250.3, 1691.6, 1642.0;
5e (248 mg, 75%) as a red solid, mp > 300 ꢁC. From 5e
(150 mg, 0.42 mmol) and N,N-dimethylethane-1,2-di-
amine (103 mg, 1.17 mmol) in absolute EtOH (15 ml)
3
HRMS-EI (70 eV) m/z calcd for C H N O
2
3
2
3
20
4
84.1586, found 384.1584.
yielded 6e (128 mg, 77%) as a red solid, mp 272–
1
4
.2.2. 5-[2-(Dimethylamino)ethyl]-9-(4-chlorophenyl)-5,8-
273 ꢁC; H NMR (400 MHz, DMSO-d ) d 8.82 (d,
6
dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6b).
From 4 (200 mg, 0.88 mmol) and 4-chloro-benzalde-
hyde (148 mg, 1.05 mmol), and NaHSO3 (137 mg,
J = 7.6, 1H, ArH), 8.52 (s, 1H, ArH), 8.38 (d, J = 7.2,
1H, ArH), 8.07 (d, J = 8.8, 2H, ArH), 7.84 (dd,
J = 7.6, 7.2, 1H, ArH), 6.86 (d, J = 8.8, 2H, ArH),
4.14 (t, J = 6.8, 2H, CH NCO), 3.18 (s, 6H, N(CH ) ),
1
.32 mmol) in DMF (15 ml) yielded 5b (223 mg, 73%)
as a yellow solid, mp > 300 ꢁC. From 5b (150 mg,
.43 mmol) and N,N ꢀ dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
b (137 mg, 76%) as a yellow solid, mp 274–275 ꢁC;
2
3 2
2.51 (t, J = 6.8, 2H, CH N), 2.51 (s, 6H, 2· CH ), 2.22
2
3
ꢀ
1
0
(
6
(s, 6H, 2· CH ); IR (KBr, cm ) 3261.4, 1691.0,
3
1642.3; HRMS-EI (70 eV) m/z calcd for C H N O
2
2
5
25
5
427.2008, found 427.1998.
1
H NMR (400 MHz, DMSO-d ) d 8.81 (d, J = 8.0,
6
1
ArH), 8.23 (d, J = 8.4, 2H, ArH), 7.88 (dd, J = 8.0,
H, ArH), 8.57 (s, 1H, ArH), 8.40 (d, J = 7.6, 1H,
4.2.6. 5-[2-(Dimethylamino)ethyl]-9-[4-(hydroxyl)phenyl]-
5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6f).
From 4 (200 mg, 0.88 mmol) and 4-hydroxy-benzaldehyde
7
.6, 1H, ArH), 7.66 (d, J = 8.4, 2H, ArH), 4.15 (t,
J = 6.4, 2H, CH NCO), 2.55 (t, J = 6.4, 2H, CH N),
(118 mg, 0.97 mmol), and NaHSO (137 mg, 1.32 mmol)
3
2
2
ꢀ
1
2
1
4
.25 (s, 6H, 2· CH ); IR (KBr, cm ) 3274.7, 1682.5,
in DMF (15 ml) yielded 5f (226 mg, 78%) as a yellow solid,
mp > 300 ꢁC. From 5f (150 mg, 0.45 mmol) and N,N-
dimethylethane-1,2-diamine (103 mg, 1.17 mmol) in abso-
3
647.7; HRMS-EI (70 eV) m/z calcd for C H ClN O
4
2
3
19
2
18.1197, found 418.1198.
lute EtOH (15 ml) yielded 6f (140 mg, 77%) as a yellow
1
4
.2.3. 5-[2-(Dimethylamino)ethyl]-9-[4-(trifluoromethyl)
solid, mp > 300 ꢁC; H NMR (400 MHz, DMSO-d ) d
6
phenyl]-5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-
dione (6c). From 4 (200 mg, 0.88 mmol) and 4-trifluo-
romethyl-benzaldehyde (168 mg, 0.97 mmol), and
8.85 (d, J = 8.4, 1H, ArH), 8.58 (s, 1H, ArH), 8.41 (d,
J = 7.2, 1H, ArH), 8.12 (d, J = 8.8, 2H, ArH), 7.88 (dd,
J = 8.4, 7.2, 1H, ArH), 6.99 (d, J = 8.8, 2H, ArH), 4.16
(t, J = 6.8, 2H, CH NCO), 2.55 (t, J = 6.8, 2H, CH N),
NaHSO (137 mg, 1.32 mmol) in DMF (15 ml) yielded
3
2
2
ꢀ
1
5
c (226 mg, 74%) as a yellow solid, mp > 300 ꢁC. From
c (150 mg, 0.39 mmol) and N,N-dimethylethane-1,2-
2.25 (s, 6H, 2· CH ); IR (KBr, cm ) 3442.0, 3190.8,
3
5
diamine (103 mg, 1.17 mmol) in absolute EtOH (15 ml)
yielded 6c (135 mg, 76%) as a yellow solid, mp 268–
1687.3, 1646.6; HRMS-EI (70 eV) m/z calcd for
C H N O 400.1535, found 400.1534.
23
20
4 3
1
270 ꢁC; H NMR (400 MHz, DMSO-d ) d 8.67 (d,
J = 8.4, 1H, ArH), 8.40 (s, 1H, ArH), 8.34 (d, J = 8.0,
4.2.7. 5-[2-(Dimethylamino)ethyl]-9-(4-methoxylphenyl)-
5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione
(6g). From 4 (200 mg, 0.88 mmol) and 4-methoxy-
benzaldehyde (132 mg, 0.97 mmol), and NaHSO3
(137 mg, 1.32 mmol) in DMF (15 ml) yielded 5g
(211 mg, 70%) as a yellow solid, mp > 300 ꢁC. From
5g (150 mg, 0.44 mmol) and N,N-dimethylethane-1,2-
diamine (135 mg, 1.17 mmol) in absolute EtOH
6
2
2
H, ArH), 8.31 (d, J = 7.6, 1H, ArH), 7.90 (d, J = 8.0,
H, ArH), 7.80 (dd, J = 8.4, 7.6, 1H, ArH), 4.08 (t,
J = 6.8, 2H, CH NCO), 2.51 (t, J = 6.8, 2H, CH N),
2
2
ꢀ
1
2
1
4
.25 (s, 6H, 2· CH ); IR (KBr, cm ) 3254.8, 1700.4,
642.7; HRMS-EI (70 eV) m/z calcd for C H F N O
2
3
2
4
19
3
4
52.1460, found 452.1464.
(
15 ml) yielded 6g (128 mg, 75%) as a yellow solid,
1
4
5
.2.4. 5-[2-(Dimethylamino)ethyl]-9-[4-(methyl)phenyl]-
,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione
mp 249–251 ꢁC; H NMR (400 MHz, DMSO-d ) d
8.84 (d, J = 8.0, 1H, ArH), 8.57 (s, 1H, ArH), 8.40
(d, J = 6.8, 1H, ArH), 8.20 (d, J = 8.8, 2H, ArH),
7.87 (dd, J = 8.0, 6.8, 1H, ArH), 7.16 (d, J = 8.8, 2H,
6
(
6d). From 4 (200 mg, 0.88 mmol) and 4-methyl-benzal-
dehyde (117 mg, 0.97 mmol), and NaHSO3 (137 mg,
.32 mmol) in DMF (15 ml) yielded 5d (241mg, 76%)
as a yellow solid, mp > 300 ꢁC. From 5d (150 mg,
.46 mmol) and N,N-dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
d (138 mg, 72%) as a yellow solid, mp 269–271 ꢁC;
1
ArH), 4.15 (t, J = 6.4, 2H, CH NCO), 3.72 (s, 3H,
2
OCH ,) 2.54 (t, J = 6.4, 2H, CH N), 2.23 (s, 6H, 2·
3
2
ꢀ1
0
(
6
CH ); IR (KBr, cm
)
3288.0, 1685.3, 1640.3;
3
HRMS-EI (70 eV) m/z calcd for C H N O
24 22 4 3
414.1692, found 414.1700.

F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
5119
1
4
5
.2.8. 5-[2-(Dimethylamino)ethyl]-9-[4-(ethoxyl)phenyl]-
,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione
as
a
brown solid, mp 212–213 ꢁC;
H
NMR
(500 MHz, DMSO-d ) d 8.73 (d, J = 6.7, 1H), 8.51
6
(
6h). From 4 (200 mg, 0.88 mmol) and 4-ethoxy-benzal-
dehyde (145 mg, 0.97 mmol) and NaHSO3 (137 mg,
.32 mmol) in DMF (15 ml) yielded 5h (226 mg, 72%)
as a yellow solid, mp > 300 ꢁC. From 5h (150 mg,
.42 mmol) and N,N-dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
(br s, 2H, ArH and FuranH), 8.36 (d, J = 7.0), 7.90
(s, 1H, FuranH), 7.83 (dd, J = 6.7, 7.0, 1H, ArH),
7.16 (s, 1H, FuranH), 4.12 (t, J = 6.7, 2H, CH NCO),
2
1
2.55 (t, J = 6.9, 2H, CH N), 2.24 (s, 6H, 2· CH );
2
3
ꢀ
1
IR (KBr, cm ) 3284.9, 1686.7, 1646.0; HRMS-EI
0
(
(70 eV) m/z calcd for C H N O 374.1379, found
2
1
18
4
3
6
h (133 mg, 74%) as a yellow solid, mp 287–288 ꢁC;
374.1377.
1
H NMR (400 MHz, DMSO-d ) d 8.84 (d, J = 8.8, 1H,
6
ArH), 8.58 (s, 1H, ArH), 8.40 (d, J = 7.2, 1H, ArH),
8
4.2.12. 5-[2-(Dimethylamino)ethyl]-9-(3-thienyl)-5,8-dihy-
drobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6l). From
4 (200 mg, 0.88 mmol) and thiophene-3-carbaldehyde
.15 (d, J = 8.0, 2H, ArH), 7.88 (dd, J = 8.8, 7.2, 1H,
ArH), 7.41 (d, J = 8.0, 2H, ArH), 4.15 (t, J = 6.4, 2H,
CH NCO), 2.54 (t, J = 6.4, 2H, CH N), 2.23 (s, 6H,
(108 mg, 0.97 mg), and NaHSO (137 mg, 1.32 mmol)
3
2
2
ꢀ
1
2
· CH ); IR (KBr, cm ) 3257.4, 1690.2, 1642.6;
HRMS-EI (70 eV) m/z calcd for C H N O
3
in DMF (15 ml) yielded 5l (202 mg, 76%) as a brown so-
lid, mp > 300 ꢁC. From 5l (150 mg, 0.47 mmol) and N,N-
dimethylethane-1,2-diamine (103 mg, 1.17 mmol) in
absolute EtOH (15 ml) yielded 6l (140 mg, 72%) as a yel-
3
2
5
24
4
4
28.1848, found 428.1849.
1
4.2.9. 5-[2-(Dimethylamino)ethyl]-9-(3-methoxy-4-hydroxyl-
low solid, mp 249–250 ꢁC; H NMR (500 MHz, DMSO-
phenyl)-5,8-dihydrobenz[de]imidazo[4,5-g]iso-quinoline-4,6-
dione (6i). From 4 (200 mg, 0.88 mmol) and 3-methyl-
oxy-4-hydroxy-benzaldehyde (147 mg, 0.97 mmol), and
d ) d 8.76 (d, J = 7.8, 1H, ArH), 8.53 (s, 1H, ArH), 8.36
6
(d, J = 9.5, 1H, ArH), 8.35 (s, 1H, ThiopheneH), 7.85
(dd, J = 7.8, 9.5, 1H, ArH), 7.77 (q, 1H, ThiopheneH),
NaHSO (137 mg, 1.32 mmol) in DMF (15 ml) yielded
3
4.11 (t, J = 7.0, 2H, CH NCO), 2.51 (t, J = 6.9, 2H,
2
ꢀ
1
5
i (246 mg, 78%) as a yellow solid, mp > 300 ꢁC. From
i (150 mg, 0.42 mmol) and N,N-dimethylethane-1,2-
diamine (103 mg, 1.17 mmol) in absolute EtOH (15 ml)
CH N), 2.21 (s, 6H, 2· CH ); IR (KBr, cm ) 3332.3,
2
3
5
1683.8, 1637.2; HRMS-EI (70 eV) m/z calcd for
C H N O S 390.1150, found 390.1147.
2
1
18
4
2
yielded 6i (126 mg, 70%) as an orange solid,
1
mp > 300 ꢁC; H NMR (400 MHz, DMSO-d ) d 8.89
4.2.13. 5-[2-(Dimethylamino)ethyl]-9-(2-furyl)-5,8-di-
hydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6m).
From 4 (200 mg, 0.88 mmol) and furan-2-carbaldehyde
6
(
d, J = 7.6, 1H, ArH), 8.60 (s, 1H, ArH), 8.44 (d,
J = 6.8, 1H, ArH), 7.91 (dd, J = 7.6, 6.8, 1H, ArH),
.83 (s, 1H, ArH), 7.74 (d, J = 8.0, 1H, ArH), 6.98 (d,
J = 8.0, 1H, ArH), 4.19 (t, J = 6.4, 2H, CH NCO),
7
(93 mg, 0.97 mmol), and NaHSO (137 mg, 1.32 mmol)
3
in DMF (15 ml) yielded 5m (200 mg, 75%) as a brown
solid, mp > 300 ꢁC. From 5m (135 mg, 0.49 mmol) and
N,N-dimethylethane-1,2-diamine (103 mg, 1.17 mmol)
in absolute EtOH (15 ml) yielded 6m (128 mg, 73%) as
2
3
(
.98 (s, 3H, OCH ), 2.56 (t, J = 6.4, 2H, CH N), 2.22
3 2
ꢀ
1
s, 6H, 2· CH ); IR (KBr, cm ) 3369.8, 3189.8,
683.5, 1648.7; HRMS-EI (70 eV) m/z calcd for
C H N O 430.1641, found 430.1641.
3
1
1
an orange solid, mp 240–241 ꢁC; H NMR (500 MHz,
2
4
22
4
4
DMSO-d ) d 8.77 (d, J = 8.1, 1H, ArH), 8.52 (s, 1H,
6
4
.2.10. 5-[2-(Dimethylamino)ethyl]-9-[3,4-(dimethoxyl)-
phenyl]-5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,
-dione (6j). From 4 (200 mg, 0.88 mmol) and 3,4-dimeth-
yloxy-benzaldehyde (160 mg, 0.97 mmol), and NaHSO3
137 mg, 1.32 mmol) in DMF (15 ml) yielded 5j (260 mg,
ArH), 8.37 (d, J = 7.2, 1H, ArH), 8.01 (br s, 1H, Fur-
anH), 7.83 (dd, J = 8.1, 7.2, 1H, ArH), 7.34 (d,
J = 3.4, 1H, FuranH), 6.78 (q, 1H, FuranH), 4.14 (t,
J = 6.9, 2H, CH NCO), 2.56 (t, J = 4.7, 2H, CH N),
6
2
2
ꢀ
1
(
2.25 (s, 6H, 2· CH ); IR (KBr, cm ) 3113.3, 1690.3,
3
7
0
9%) as a yellow solid, mp > 300 ꢁC. From 5j (150 mg,
.40 mmol) and N,N-dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded 6j
1651.2; HRMS-EI (70 eV) m/z calcd for C H N O
3
2
1
18
4
374.1379, found 374.1375.
(
(
1
135 mg, 76%) as an orange solid, mp 247–249 ꢁC; H
4.2.14. 5-[2-(Dimethylamino)ethyl]-9-(2-thienyl)-5,8-dihy-
drobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6n).
From 4 (200 mg, 0.88 mmol) and thiophene-2-carbalde-
hyde (108 mg, 0.97 mg), and NaHSO3 (137 mg,
1.32 mmol) in DMF (15 ml) yielded 5n (222 mg, 79%)
as a yellow solid, mp > 300 ꢁC. From 5n (150 mg,
NMR (400 MHz, DMSO-d ) d 8.77 (d, J = 7.6, 1H,
6
ArH), 8.46 (s, 1H, ArH), 8.33 (d, J = 7.2, 1H, ArH),
7.81 (dd, J = 7.6, 7.2, 1H, ArH), 7.78–7.77 (m, 2H,
ArH), 7.12 (d, J = 8.4, 1H, ArH), 4.10 (t, J = 7.2, 2H,
CH NCO), 3.92 (s, 3H, OCH ), 3.87 (s, 3H, OCH ), 2.52
2
(t, J = 6.4, 2H, CH N), 2.24 (s, 2· CH , 6H); IR (KBr,
cm ) 3294.7, 1686.5, 1639.8; HRMS-EI (70 eV) m/z calcd
3
3
0.47 mmol)
and
N,N-dimethylethane-1,2-diamine
2
3
ꢀ
1
(103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
6n (129 mg, 70%) as a yellow solid, mp 248–250 ꢁC;
for C H N O 444.1798, found 444.1799.
4
2
5
24
4
1
H NMR (400 MHz, DMSO-d ) d 8.80 (d, J = 8.0, 1H,
6
4
.2.11. 5-[2-(Dimethylamino)ethyl]-9-(3-furyl)-5,8-di-
ArH), 8.57 (s, 1H, ArH), 8.41 (d, J = 6.4, 1H, ArH),
7.95 (d, J = 3.2, 1H, ThiopheneH), 7.87 (dd, J = 8.0,
6.4, 1H, ArH), 7.82 (d, J = 4.0, 1H, ThiopheneH), 7.30
(d, J = 3.2, 4.0, 1H, ThiopheneH), 4.16 (t, J = 6.8,
hydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6k).
From 4 (200 mg, 0.88 mmol) and furan-3-carbaldehyde
(
93 mg, 0.97 mmol), and NaHSO (137 mg, 1.32 mmol)
3
in DMF (15 ml) yielded 5k (205 mg, 77%) as a yellow
solid, mp > 300 ꢁC. From 5k (150 mg, 0.49 mmol) and
N,N-dimethylethane-1,2-diamine (103 mg, 1.17 mmol)
in absolute EtOH (15 ml) yielded 6k (138 mg, 75%)
1H, ArH), 2.54 (t, J = 7.2, 2H, CH N), 2.24 (s, 6H, 2·
2
ꢀ1
CH ); IR (KBr, cm ) 3287.3, 1685.1, 1615.2; HRMS-
EI (70 eV) m/z calcd for C H N O S 390.1150, found
3
2
1
18
4
2
390.1147.

5120
F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
4
.2.15. 5-[2-(Dimethylamino)ethyl]-9-(2-pyrrolyl)-5,8-
(103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
1
dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6o).
From 4 (200 mg, 0.88 mmol) and 1H-pyrrole-2-carbal-
dehyde (92 mg, 0.97 mmol), and NaHSO3 (137 mg,
6r (135 mg, 74%) as a brown solid, mp 243–244 ꢁC; H
NMR (500 MHz, DMSO-d ) d 9.31 (s, 1H, PyridineH),
6
8.67 (d, J = 4.3, 1H, PyridineH), 8.64 (d, J = 7.9, 1H,
ArH), 8.45 (d, J = 7.10, 1H, ArH), 8.40 (s, 1H, Pyridi-
neH), 8.27 (d, J = 7.2, 1H, PyridineH), 7.76 (dd,
J = 7.9, 7.1, 1H, ArH), 7.56 (q, 1H, pyridineH), 4.06
1
.32 mmol) in DMF (15 ml) yielded 5o (178 mg, 67%)
as a yellow solid, mp > 300 ꢁC. From 5o (150 mg,
.50 mmol) and N,N-dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
o (138 mg, 75%) as a brown solid, mp 247–249 ꢁC;
0
(
6
(t, J = 6.9, 2H, CH NCO), 2.55 (t, J = 7.0, 2H,
2
ꢀ
1
CH N), 2.26 (s, 6H, 2· CH ); IR (KBr, cm ) 3184.3,
2
3
1
H NMR (500 MHz, DMSO-d ) d 8.82 (d, J = 8.1,
1696.8, 1650.0; HRMS-EI (70 eV) m/z calcd for
C H N O 385.1539, found 385.1549.
6
1
H, ArH), 8.57 (s, 1H, ArH), 8.41 (d, J = 7.3, 1H,
ArH), 7.87 (dd, J = 8.1, 7.3, 1H, ArH), 7.03 (br s, 1H,
PyrioleH), 7.00 (d, J = 2.8, 1H, PyrroleH), 6.27 (dd,
J = 3.5, 2.8, 1H, PyrroleH), 4.15 (t, J = 7.0, 2H,
CH NCO), 2.51 (t, J = 7.1, 2H, CH N), 2.21 (s, 6H,
2
2
19
5
2
4.2.19. 5-[2-(Dimethylamino)ethyl]-9-(4-pyridinyl)-5,8-
dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6s).
From 4 (200 mg, 0.88 mmol) and pyridine-4-carbalde-
hyde (103 mg, 0.97 mmol), and NaHSO3 (137 mg,
1.32 mmol) in DMF (15 ml) yielded 5s (216 mg, 78%)
as a brown solid, mp > 300 ꢁC. From 5s (139 mg,
2
2
ꢀ1
2
· CH ); IR (KBr, cm ) 3311.5, 1692.2, 1651.9;
3
HRMS-EI (70 eV) m/z calcd for C H N O
2
3
2
1
19
5
73.1539, found 373.1537.
0
.48 mmol)
and
N,N-dimethylethane-1,2-diamine
4
.2.16. 5-[2-(Dimethylamino)ethyl]-9-(N-methyl-2-py-
(103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
6s (128 mg, 75%) as an orange solid, mp 204–205 ꢁC;
rrolyl)-5,8-dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-
dione (6p). From 4 (200 mg, 0.88 mmol) and 1-methyl-
1
H NMR (400 MHz, DMSO-d ) d 8.74 (d, J = 8.4, 2H,
6
1
NaHSO (137 mg, 1.32 mmol) in DMF (15 ml) yielded
H-pyrrole-2-carbaldehyde (105 mg, 0.97 mmol), and
PyridineH), 8.67 (d, J = 8.0, 1H, ArH), 8.41 (s, 1H,
ArH), 8.28 (d, J = 7.2, 1H, Ar), 8.07 (d, 2H, PyridineH),
7.77 (t, J = 8.0, 7.2, 1H, ArH), 4.07 (br s, 2H,
CH NCO), 2.52 (br s, 2H, CH N), 2.28 (s, 6H, 2·
3
5
p (206 mg, 74%) as a yellow solid, mp >300 ꢁC. From
p (150 mg, 0.47 mmol) and N,N-dimethylethane-1,2-
diamine (103 mg, 1.17 mmol) in absolute EtOH (15 ml)
5
2
2
ꢀ1
CH ); IR (KBr, cm ) 3332.3, 1692.4, 1645.5; HRMS-
3
+
yielded 6p (136 mg, 73%) as a brown solid, mp 252–
EI (70 eV) m/z calcd for C H N O [M+H]
2
2
2
19
5
1
2
J = 6.6, 1H, ArH), 8.53 (s, 1H, ArH), 8.40 (d, J = 6.2,
53 ꢁC; H NMR (500 MHz, DMSO-d ) d 8.81 (d,
386.1617, found 386.1626.
6
1
1
H, ArH), 7.85 (dd, J = 6.6, 6.2, 1H, ArH), 7.09 (br s,
H, PyrroleH), 7.02 (d, J = 2.8, 1H, PyrroleH), 6.23
4.3. In vitro cytotoxicity assays
(
4
dd, J = 3.5, 2.8, 1H, PyrroleH), 4.19 (s, 3H, N–CH3)
.14 (t, J = 6.9, 2H, CH NCO), 2.51 (t, J = 7.2, 2H,
The prepared compounds were submitted to Shanghai
Institute of Materia Medica and Dalian Medical Uni-
versity for in vitro cytotoxicity assays. Growth inhibi-
tory effect on the cell lines (P388, SMMC-7721, HeLa,
2
ꢀ
1
CH N), 2.21 (s, 6H, 2· CH ); IR (KBr, cm ) 3265.0,
1693.8, 1640.0; HRMS-EI (70 eV) m/z calcd for
C H N O 387.1695, found 387.1698.
2
3
1
4
and HL-60) was measured by the MTT assay. For
A-549 cell lines, the growth inhibition was tested by
2
2
21
5
2
1
5
4
.2.17. 5-[2-(Dimethylamino)ethyl]-9-(2-pyridinyl)-5,8-
the sulforhodamine B (SRB) assay.
dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6q).
From 4 (200 mg, 0.88 mmol) and pyridine-2-carbalde-
hyde (103 mg, 0.97 mmol), and NaHSO3 (137 mg,
4.4. DNA binding experiments
1
.32 mmol) in DMF (15 ml) yielded 5q (216 mg, 78%)
as a brown solid, mp > 300 ꢁC. From 5q (150 mg,
.48 mmol) and N,N-dimethylethane-1,2-diamine
103 mg, 1.17 mmol) in absolute EtOH (15 ml) yielded
4.4.1. DNA. Calf-thymus DNA was purchased from the
Sino–American Biotechnology Company. Solutions of
DNA in 30 mM Tris–HCl buffer (pH 7.2) and PBE buf-
fer (pH 7.1) gave a ratio of UV absorbance at 260 and
280 nm of 1.8–1.9:1, indicating that the DNA was suffi-
ciently free of protein. The concentration of calf-thymus
DNA was determined spectrophotometrically assuming
0
(
6
q (143 mg, 77%) as a yellow solid, mp 231–233 ꢁC;
1
H NMR (500 MHz, DMSO-d ) d 8.73 (m, 2H, ArH
6
and PyridineH), 8.49 (s, 1H, ArH), 8.29 (m, 2H, ArH
and PyridineH), 7.99 (t, J = 7.3, 1H, PyridineH), 7.77
ꢀ
1
ꢀ1
the molar absorption is 6600 M cm (260 nm).
(
J = 6.9, 2H, CH NCO), 2.56 (t, J = 6.8, 2H, CH N),
t, J = 7.7, 1H, ArH), 7.53 (q, 1H, PyridineH), 4.09 (t,
4.4.2. UV–vis measurements. Spectroscopic titrations
were carried out at room temperature to determine the
binding affinity between DNA and each compound. Ini-
tially, solutions of the blank buffer were placed in the
reference and sample cuvettes (1 cm path length),
respectively, and then the first spectrum was recorded
in the range 200–600 nm. During the titration, aliquots
of buffered DNA solution were added to each cuvette
to eliminate the absorbance of DNA itself, and the solu-
tions were mixed by repeated inversion. After mixing for
10 min, the absorption spectra were recorded. The titra-
tion processes were repeated until there was no change
2
2
ꢀ
1
2
1
3
.26 (s, 6H, 2· CH ); IR (KBr, cm ) 3189.8, 1692.1,
3
650.6; HRMS-EI (70 eV) m/z calcd for C H N O
2
2
2
19
5
85.1539, found 385.1538.
4
.2.18. 5-[2-(Dimethylamino)ethyl]-9-(3-pyridinyl)-5,8-
dihydrobenz[de]imidazo[4,5-g]isoquinoline-4,6-dione (6r).
From 4 (200 mg, 0.88 mmol) and pyridine-3-carbalde-
hyde (103 mg, 0.97 mmol), and NaHSO3 (137 mg,
1
.32 mmol) in DMF (15 ml) yielded 5r (191 mg, 69%)
as a yellow solid, mp > 300 ꢁC. From 5r (150 mg,
.48 mmol) and N,N-dimethylethane-1,2-diamine
0

F. Li et al. / Bioorg. Med. Chem. 15 (2007) 5114–5121
5121
in the spectra for at least four titrations indicating bind-
ing saturation had been achieved. The UV–vis titrations
for each sample were repeated at least three times.
Conlon, D.; Bousquet, P. F.; Romerdahl, C. A.; Robin-
son, S. P. Anti-Cancer Drug Des. 1996, 11, 297.
. (a) Sami, S. M.; Dorr, R. T.; Alberts, D. S.; Remers, W.
A. J. Med. Chem. 1993, 36, 765; (b) Sami, S. M.; Dorr, R.
T.; Alberts, D. S.; Remers, W. A. J. Med. Chem. 1995, 38,
6
4
.4.3. Melting temperature measurements. Measurements
9
83; (c) Sami, S. M.; Dorr, R. T.; Solyom, A. M.; Alberts,
D. S.; Bhashyam, S. I.; Remers, W. A. J. Med. Chem.
996, 39, 1609; (d) Sami, S. M.; Dorr, R. T.; Alberts, D.
were performed using 20 lM CT DNA in BPE buffer,
pH 7.1 (6 mM Na HPO , 2 mM NaH PO , 1 mM
2
4
2
4
1
EDTA). The temperature inside the cuvette was mea-
sured with a platinum probe; it was increased over the
range 50–92 ꢁC with a heating rate of 1 ꢁC/min. The
S.; Solyom, A. M.; Remers, W. A. J. Med. Chem. 1996,
39, 4978; (e) Sami, S. M.; Dorr, R. T.; Alberts, D. S.;
Solyom, A. M.; Remers, W. A. J. Med. Chem. 2000, 43,
3067.
‘
melting’ temperature Tm was taken as the midpoint of
7
. (a) Brana, F. M.; Cacho, M.; Garcia, M. A.; Pascual-
Teresa, B.; Ramos, A.; Acero, N.; Llinares, F.; Munoz-
Mingarro, D.; Abradelo, C.; Rey-Stolle, M. F.; Yuste, M.
J. Med. Chem. 2002, 45, 5813; (b) Brana, F. M.; Cacho,
M.; Ramos, A.; Dominguez, M. T.; Pozuelo, J. M.;
Abradelo, C.; Rey-Stolle, M. F.; Yuste, M.; Carrasco, C.;
Bailly, C. Org. Biomol. Chem. 2003, 1, 648; (c) Brana, F.
M.; Cacho, M.; Garcia, M. A.; Pascual-Teresa, B.;
Ramos, A. M.; Dominguez, T.; Pozuelo, J. M.; Abradelo,
C.; Rey-Stolle, M. F.; Yuste, M.; Banez-Coronel, M.;
Lacal, J. C. J. Med. Chem. 2004, 47, 1391; (d) Brana, F.
M.; Gradillas, A.; Gomez, A.; Acero, N.; Llinares, F.;
Munoz-Mingarro, D.; Abradelo, C.; Rey-Stolle, M. F.;
Yuste, M.; Campos, J.; Gallo, M. A.; Espinosa, A. J. Med.
Chem. 2004, 47, 2236.
the hyperchromic transition. Data are presented as Tm
versus the temperature.
4
.4.4. Viscometric titrations. Viscosity measurements
were carried out using an Ubbelodhe viscometer main-
tained at a constant temperature at 25 (±0.1) ꢁC in a
thermostated bath. The DNA samples contained
approximately 200 base pairs. Flow times were measured
with a digital stopwatch and each sample was measured
three times and an average flow time was calculated.
1
/3
Data are presented as (g/g0) versus the ratio of the con-
centration of compounds to that of DNA, where g is the
viscosity of DNA in the presence of compound and g is
0
the viscosity of DNA in the absence of compound.
8
. (a) Li, Y.; Xu, Y.; Qian, X.; Qu, B. Tetrahedron Lett. 2004,
5, 1247; (b) Li, Z.; Yang, Q.; Qian, X. Bioorg. Med.
4
Chem. Lett. 2005, 15, 3143; (c) Li, Z.; Yang, Q.; Qian, X.
Bioorg. Med. Chem. 2005, 13, 4864.
Acknowledgments
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Strekowski, L.; Wilson, W. D. Biochemistry 2000, 39,
We are grateful to the National Key Project for Basic
Research (2003CB114400), the National Natural Sci-
ence Foundation of China, and the Ministry of Science
and Technology Foundation of Shanghai (04DZ05605)
for financial support of this research.
1
3210.
1
1
0. (a) Strekowski, L.; Mokrosz, J. L.; Honkan, V. A.;
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