Synthesis and cytotoxic evaluation of 1-carboxamide and 1-amino side chain substituted β-carbolines

Article abstract of DOI:10.1016/j.ejmech.2010.08.065

The condensation of alkylenediamine with ethyl β-carboline-1- carboxylate and 1-bromo-β-carboline gave β-carboline-1-carboxamides and 1-amino-β-carbolines, respectively. Some of these β-carbolines were active against a panel of human tumor cell lines, and 1-amino derivatives were more potent than their 1-carboxamide congeners. In particular, among the 1-amino-β-carbolines, the N⁹-arylated alkyl substituted β-carbolines exhibited the most interesting cytotoxic activities with IC₅₀ value of lower than 20 μM. The preliminary structure-activity relationships (SARs) analysis suggested that (1) 1-amino substituents were the advisable pharmacophoric group for enhanced cytotoxic activities; (2) the introduction of appropriate arylated alkyl groups into position-9 of β-carboline facilitated their cytotoxic potencies.

Full text of DOI:10.1016/j.ejmech.2010.08.065

European Journal of Medicinal Chemistry 45 (2010) 5513e5519
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Short communication
Synthesis and cytotoxic evaluation of 1-carboxamide and 1-amino side chain
substituted
b-carbolines
,
a
a
b
b
b
a
Chunming Ma a, Rihui Cao a , Buxi Shi , Xiantai Zhou , Qin Ma , Jie Sun , Liang Guo , Wei Yi ,
*
Zhiyong Chen a, Huacan Song a
,
*
a School of Chemistry and Chemical Engineering, Sun Yat-sen University, 135 Xin Gang West Road, Guangzhou 510275, PR China
b Xinjiang Huashidan Pharmaceutical Co. Ltd., 45 He Nan East Road, Urumqi 830011, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
The condensation of alkylenediamine with ethyl
b
-carboline-1-carboxylate and 1-bromo-
-carbolines, respectively. Some of these
were active against a panel of human tumor cell lines, and 1-amino derivatives were more potent than
their 1-carboxamide congeners. In particular, among the 1-amino-
-carbolines, the N9-arylated alkyl
substituted -carbolines exhibited the most interesting cytotoxic activities with IC50 value of lower than
20 M. The preliminary structureeactivity relationships (SARs) analysis suggested that (1) 1-amino
substituents were the advisable pharmacophoric group for enhanced cytotoxic activities; (2) the intro-
b
-carboline
Received 13 March 2010
Received in revised form
24 July 2010
Accepted 29 August 2010
Available online 8 September 2010
gave
b
-carboline-1-carboxamides and 1-amino-
b
b-carbolines
b
b
m
Keywords:
Synthesis
duction of appropriate arylated alkyl groups into position-9 of
potencies.
b-carboline facilitated their cytotoxic
b
-Carboline
Ó 2010 Elsevier Masson SAS. All rights reserved.
Cytotoxic
SARs
1. Introduction
complex polycyclic ring system in position-1 of b-carboline nucleus
of manzamine A can be replaced with simpler amino substituents
to give active compounds [9].
Our previous attention was focused on the incorporating various
substituents into position-3 and 9 of b-carboline nucleus [22e27].
Structure-activity relationships (SARs) for in vitro and in vivo anti-
tumor activities disclosed that (1) the antitumor potential of
The
synthetic products associated with a wide spectrum of biochemical
and pharmaceutical functions [1]. Recently, the -carboline alka-
loids have been characterized as a class of potential antitumor
agents, and a large number of natural and synthetic -carbolines
b-carboline nucleus is present in many natural and
b
b
acting as antitumor agents were reported [2e10]. Many studies
suggested that these compounds exerted their antitumor activities
through multiple mechanisms of action including intercalation into
DNA [3,8,11], inhibition topoisomerase I and II [5,12,13], CDK
(cyclin-dependent kinase) [14e16], MK-2 (mitogen activated
protein kinase-activated protein kinase 2) [17,18], PLK1 (polo-like
kinase) [19], kinesin-like protein Eg5 [20] and IKK (I-kappa-B
kinase) [21].
b
-carbolines was correlated to both the planarity of the molecule
and the presence of substituents in position-3 and 9 of -carboline
nucleus; (2) the introduction of appropriate substituents into
position-9 of -carboline nucleus played a vital role in the modu-
b
b
lation of their antitumor efficacies.
In continuing search for novel antitumor agents endowed with
better pharmacological profiles and study in depth the influence of
the substituent in position-1 and 9 of b-carboline nucleus, in the
Previous attempts were focused on incorporating substituents
present investigation, we reported the design, synthesis and cyto-
toxic evaluation of novel antitumor agents bearing carboxamide or
amino substituents in position-1 and alkyl or arylated alkyl groups
into position-1 and 3 of
b-carboline nucleus. The b-carbolines
bearing a flexible alkylamine side chain in position-3 showed
potent DNA intercalating abilities resulting in remarkable anti-
in position-9 of b-carboline nucleus, respectively.
tumor potencies [3], and the b-carboline amino acid ester conju-
gates exhibited potent cytotoxic activities [6]. In addition, the
2. Chemistry
The ethyl 1,2,3,4-tetrahydro-b-carboline-1-carboxylate 2employed
in this investigation was accomplished via the well-
known PicteteSpengler reaction of tryptamine hydrochloride 1 with
ethyl glyoxylate in ethanol [28]. Oxidative aromatization of 2 with
* Corresponding authors. Tel.: þ86 20 84110918; fax: þ86 20 84112245.
E-mail addresses: caorihui@mail.sysu.edu.cn (R. Cao), yjhxhc@mail.sysu.edu.cn
(H. Song).
0223-5234/$ e see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2010.08.065

5514
C. Ma et al. / European Journal of Medicinal Chemistry 45 (2010) 5513e5519
addition of the relevant appropriate alkylating and arylating agents
to provide 12aed. The reaction of 10 and 12aed with an access of
various diamines without solvent by microwave-assisted heating
(170 ꢀC, 30min) provided the corresponding amines 11aeb and
13aef in good yield (Scheme 2). The chemical structures of all the
synthesized compounds were characterized by MS, IR, 1H NMR and
13C NMR spectra.
3. Results and discussion
The cytotoxic potential of all synthesized
b-carbolines was
evaluated in vitro against a panel of human tumor cell lines and
compared with the reference drugs cisplatin that has been in wide
clinical use. In order to enhance the solubility in aqueous solution,
all compounds were prepared in the form of hydrochloride salt
a
Scheme 1. Synthesis of 1-carboxamide substituted
b-carbolines 4aec, 5aeb and
before use. As predicted, the hydrochloride salt of
b-carbolines
7aeb. a(i) OHCeCO2Et, EtOH, reflux; (ii) MnO2, toluene, reflux; (iii) NH2(CH2)2NH2 or
NH2(CH2)6NH2 or NH2(CH2)3N(C2H5)2, stirred at RT or microwave irradiation, 170 ꢀC,
30 min; (iv) CH3I or C6H5Br, EA, reflux; (v) DMF, NaH, C6H5(CH2)3Br; (vi) NH2(CH2)2NH2
or NH2(CH2)3N(C2H5)2, microwave irradiation, 170 ꢀC, 30 min.
bearing carboxamide or amino substituents in position-1 showed
excellent water-solubility (more than 200 mg/ml). The tumor cell
line panel consisted of gastric carcinoma (BGC-823), liver carci-
noma (HepG2), breast carcinoma (MCF-7), renal carcinoma (OS-RC-
2, 786-0 and 769-P), melanoma (A375), colon carcinoma (HT-29),
epidermoid carcinoma of the nasopharynx (KB) and prostate
carcinoma (22RV1). The results were summarized in Table 1.
It was apparent that 1-amino derivatives 13aef showed more
potent cytotoxic potencies than the corresponding 1-carboxamide
derivatives 4aec, 5aeb and 7aeb. Of all 1-carboxamide derivatives,
compounds 4aec exhibited moderate cytotoxic activities against
MnO2 in refluxing toluene afforded the desired ethyl b-carboline-1-
carboxylate 3. This sequence of reactions can be easily scaled up to give
enough material 3 for further transformations. The reaction of
1-bromo-3-phenylpropane with compound 3 by the action of sodium
hydride in anhydrous DMF furnished ethyl 9-(3-phenylpropyl)-b-car-
boline-1-carboxylate 6. The condensation of compounds 3 and 6 with
an excess of diamines by heating or subjecting to microwave irradia-
tion (170 ꢀC, 30 min) gave the amidated derivatives 4aec and 7aeb in
good yield. The methylated or benzylated quarternary
5aeb were prepared from the corresponding -carboline 4c by the
human tumor cell lines with IC50 values range from 22.1 to 243
As predicted, incorporating a 3-phenylpropyl group into position-9
of -carboline nucleus of compounds 4a and 4c led to compounds
7a and 7b, which demonstrated significant cytotoxic potencies
with IC50 values of lower than 50 M against 10 human tumor cell
lines. Unfortunately, the quarternary -carboline salts 5aeb were
almost inactive at the concentration of 300 M.
mM.
b-carboline salts
b
b
addition of methyl iodide or benzyl bromide in refluxing ethyl acetate,
respectively (Scheme 1).
m
b
The intermediate 1-bromo-b-carboline 10 was prepared readily
m
from tryptamine 1 in three steps according to already published
methods [29]. The N9-position of compound 10 was alkylated or
arylated by the action of sodium hydride in dry DMF followed by
As shown in Table 1, compound 11a bearing a aminoethylamino
side chain group showed moderate cytotoxic activity, while
replacement of aminoethylamino group of 11a with
ii
i
NH
NH
NH2
N
N
N
H
H
O
O
H
8
9
1
iv
iii
N
N
N
N
R1
H
Br
H
10
11a R1=NH(CH2)2NH2
11b R1=NH(CH2)2OH
v
vi
N
N
N
R1
N
Br
R9
R9
13a R1=NH(CH2)2NH2 R9=n-C4H9
12a R9= n-C4H9
13b R1=NH(CH2)2NH2 R9=CH2C6H4 (p-F)
13c R1=NH(CH2)2NH2 R9=CH2C6F5
13d R1=NH(CH2)2NH2 R9=(CH2)3C6H5
13e R1=NH(CH2)4NH2 R9=(CH2)3C6H5
13f R1=NH(CH2)6NH2 R9=(CH2)3C6H5
12b R9 = CH2C6H4 (p-F)
12c R9 = CH2C6F5
12d R9 = (CH2)3C6H5
Scheme 2. a Synthesis of 1-amino substituted
b
-carbolines 11aeb and 13aef. a(i) toluene, triphosgene, Et3N, 30% HBr/HAc, reflux; (ii) THF, DDQ, stirred at RT; (iii) POBr3, C6H5OCH3,
120 ꢀC; (iv) NH2(CH2)2NH2 or HO(CH2)2NH2, CuI, reflux; (v) DMF, NaH, alkyl halogenide, stirred at RT; (vi) NH2(CH2)nNH2, microwave irradiation, 170 ꢀC, 30 min.

C. Ma et al. / European Journal of Medicinal Chemistry 45 (2010) 5513e5519
5515
Table 1
Cell growth inhibitory activity (IC50
,
m
M) of compounds 4aec, 5aeb, 7aeb, 11aeb, 12aed and 13aef against ten human cancer cell lines.
Compound
IC50
(m
M)ꢃSDa
BGC823
HepG2
MCF7
OS-RC-2
786e0
769-P
A375
HT-29
KB
22RV1
4a
4b
4c
5a
77.7 ꢃ 8.2
109 ꢃ 13.6
174 ꢃ 25.3
>300
122 ꢃ 15.6
85.5 ꢃ 9.3
243 ꢃ 26.8
>300
80.4 ꢃ 9.85
46.8 ꢃ 6.20
164 ꢃ 18.9
>300
63.9 ꢃ 5.82
58.5 ꢃ 7.61
93.9 ꢃ 14.3
>300
86.1 ꢃ 10.2
72.7 ꢃ 6.89
111 ꢃ 15.2
>300
124 ꢃ 18.6
75.3 ꢃ 8.84
54.0 ꢃ 4.86
>300
65.3 ꢃ 7.42
37.7 ꢃ 4.25
107 ꢃ 15.4
>300
55.6 ꢃ 4.85
73.2 ꢃ 6.54
61.2 ꢃ 5.86
>300
118 ꢃ 14.3
86.9 ꢃ 10.2
62.3 ꢃ 7.41
>300
124 ꢃ 20.5
33.6 ꢃ 4.25
46.2 ꢃ 4.89
>300
5b
7a
7b
>300
>300
51.1 ꢃ 6.23
22.3 ꢃ 1.87
31.4 ꢃ 3.65
87.2 ꢃ 12.1
>300
>300
137 ꢃ 16.7
11.8 ꢃ 1.04
31.4 ꢃ 2.87
31.9 ꢃ 3.56
>300
>300
>300
>300
>300
18.9 ꢃ 2.32
18.8 ꢃ 2.47
5.8 ꢃ 0.63
6.9 ꢃ 0.68
2.7 ꢃ 0.32
11.3 ꢃ 0.85
9.4 ꢃ 1.28
101 ꢃ 13.6
32.5 ꢃ 4.25
61.0 ꢃ 8.62
31.5 ꢃ 2.89
272 ꢃ 25.2
>300
>300
>300
>300
71.4 ꢃ 8.62
10.8 ꢃ 1.09
26.9 ꢃ 2.26
41.3 ꢃ 5.45
136 ꢃ 15.6
236 ꢃ 28.7
>300
20.0 ꢃ 1.56
22.3 ꢃ 2.43
36.0 ꢃ 3.81
>300
>300
>300
15.9 ꢃ 2.20
22.1 ꢃ 3.12
30.6 ꢃ 4.56
130 ꢃ 20.1
>300
>300
>300
>300
6.6 ꢃ 0.56
4.4 ꢃ 0.39
12.8 ꢃ 1.18
13.3 ꢃ 2.30
4.0 ꢃ 0.52
12.1 ꢃ 1.08
4.6 ꢃ 0.32
15.7 ꢃ 2.21
36.9 ꢃ 4.20
40.0 ꢃ 5.59
220 ꢃ 30.5
136 ꢃ 16.5
>300
13.7 ꢃ 1.19
33.8 ꢃ 4.23
33.4 ꢃ 3.26
>300
>300
>300
17.9 ꢃ 2.68
53.4 ꢃ 6.59
33.4 ꢃ 2.89
>300
186 ꢃ 26.8
245 ꢃ 30.5
>300
86.6 ꢃ 10.3
13.3 ꢃ 1.06
9.1 ꢃ 0.87
9.9 ꢃ 1.12
5.6 ꢃ 0.48
17.5 ꢃ 1.56
21.5 ꢃ 2.56
85.7 ꢃ 10.2
9.9 ꢃ 0.96
14.0 ꢃ 2.08
25.4 ꢃ 3.26
>300
>300
>300
11a
11b
12a
12b
12c
12d
13a
13b
13c
13d
13e
13f
Cisplatin
256 ꢃ 35.2
>300
252 ꢃ 32.6
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
93.9 ꢃ 12.8
9.3 ꢃ 1.22
16.3 ꢃ 2.62
12.0 ꢃ 1.28
4.6 ꢃ 0.36
4.2 ꢃ 0.34
8.4 ꢃ 0.75
4.9 ꢃ 0.56
123 ꢃ 15.6
68.7 ꢃ 6.65
1.8 ꢃ 0.16
10.4 ꢃ 1.26
11.1 ꢃ 1.43
2.2 ꢃ 0.18
13.6 ꢃ 1.45
3.4 ꢃ 0.42
88.0 ꢃ 10.3
14.2 ꢃ 2.10
17.9 ꢃ 2.36
12.5 ꢃ 1.10
8.6 ꢃ 0.78
2.9 ꢃ 0.22
11.5 ꢃ 0.98
12.4 ꢃ 1.20
25.3 ꢃ 3.64
9.7 ꢃ 0.86
11.9 ꢃ 1.23
9.6 ꢃ 0.81
8.0 ꢃ 0.75
12.4 ꢃ 1.32
19.2 ꢃ 1.62
33.6 ꢃ 4.58
21.4 ꢃ 3.45
15.1 ꢃ 2.26
9.3 ꢃ 0.78
12.8 ꢃ 1.12
17.9 ꢃ 2.62
13.4 ꢃ 1.45
22.8 ꢃ 3.21
15.6 ꢃ 1.42
12.0 ꢃ 1.54
7.3 ꢃ 0.86
9.5 ꢃ 1.03
16.3 ꢃ 2.38
16.0 ꢃ 2.36
20.5 ꢃ 2.87
19.1 ꢃ 3.15
11.8 ꢃ 1.28
4.9 ꢃ 0.45
11.3 ꢃ 1.42
13.0 ꢃ 1.13
4.6 ꢃ 0.40
a
Cytotoxicity as IC50 for each cell line is the concentration of compound, which reduced by 50% the optical density of treated cells with respect to untreated using the MTT
M indicate less than 50% growth inhibition at 300 M.
assay. Values with standard deviations (SD) are averages of at least five independent determinations. Values >300
m
m
hydroxylethylamino group led to compound 11b, which showed no
cytotoxic efficacy at the concentration of 300 M. 1-Bromo- -car-
bolines 12aed failed to display cytotoxic activities, while
compounds 13aef, the condensation products of compounds
12aed with various diamines, showed potent cytotoxic potencies
cytotoxic potential and to elucidate SARs between substituent
properties in position-1 of -carboline nucleus and cytotoxic
efficacies, design and synthesis of more novel -carboline deriva-
m
b
b
b
tives bearing various amino side chains are needed.
with IC50 values of lower than 20
lines. Among 1-amino derivatives 13aef, compound 13bef, bearing
an arylated alkyl substituents in position-9 of -carboline nucleus
mM against most of tumor cell
5. Experimental section
b
Reagents and general methods: All reagents were purchased from
commercial suppliers and were dried and purified when necessary.
Melting points were determined with a Kofler micromelting point
apparatus without correction. ESI-MS spectra were obtained from
VG ZAB-HS spectrometer. 1H NMR and 13C NMR spectra were
recorded on a Mercury-Plus 300 spectrometer at 300 MHz and
75 MHz respectively, using TMS as internal standard and CDCl3 or
exhibited more potent cytotoxic effects than compound 13a having
an n-butyl group in position-9. In addition, compounds 13d and 13e
bearing a flexible amino side chain with two or four methylene
spacer, respectively, displayed more potent cytotoxic potencies
than compound 13f having six methylene spacer. These results
suggested that (1) the amino side chain substituents were the
advisable pharmacophoric group for the enhanced cytotoxic
activities; (2) the introduction of appropriate arylated alkyl groups
DMSO-d6 as solvent and chemical shifts (d) were expressed in ppm.
All reactions were monitored by TLC and spots were visualized with
UV light or iodine. HPLC was performed on Agilent 1100 series,
using a Waters C18 column (4.6 ꢁ 150 mm). All compounds (free
bases) were greater than 95% pure. All commercially available
reagents and solvents were used without further purification. The
into position-9 of
potencies.
b-carboline nucleus facilitated the cytotoxic
4. Conclusion
intermediate ethyl
phenylpropyl)- -carboline-1-carboxylate (6) were prepared as
previously described [22,28]. The intermediate 1-oxo-tetrahydro-
-carboline (8), 1-oxo-1,2-dihydro- -carboline (9) and 1-bromo-
carboline (10) were prepared according to literature methods [29].
b-carboline-1-carboxylate (3) and ethyl 9-(3-
In the present investigation, two different types of 1-substituted
-carbolines were designed, synthesized and their cytotoxic
b
b
potential against human tumor cell lines in culture were investi-
gated. Some of these compounds had significant cytotoxic efficacies
in comparable to the reference drug cisplatin. Preliminary struc-
tureeactivity relationships analysis indicated that the 1-amino side
chain substituents were more favorable than 1-carboxamide side
chain groups for their enhanced cytotoxic potencies. In addition,
b
b
b-
5.1. N-(2-aminoethyl)- -carboline-1-carboxamide (4a) [30]
b
the introduction of arylated alkyl groups into position-9 of
b
-car-
A mixture of ethyl b-carboline-1-carboxylate 3 (0.24 g,1.0 mmol)
boline nucleus provided compounds with greatly enhanced cyto-
toxic potencies. These results were agreement with our previous
observation that the N9-arylated alkyl substitution facilitated the
cytotoxic potencies. Moreover, our previous studies suggested that
intercalation into DNA is a major cellular event of this class of
and ethylenediamine (10 mL) was stirred at room temperature for
2 h. Aftercompletion of the reaction as indicated by TLC, the reaction
mixture was evaporated under reduced pressure and the residue
dissolved in EA (50 mL), washed with H2O. The organic phase was
dried over anhydrous Na2SO4, filtered and evaporated to give the
crude product, and then washed with anhydrous ethyl ether to
afford 4a as yellow solid (0.21 g, 85%), mp 118e120 ꢀC. ESI-MS m/z
molecules [31] and b-carbolines can pass through cell membrane
and penetrate into nucleus quickly resulting in intercalating into
DNA in cells [32]. Consequently, such compounds were expected to
exert their tumor cell killing effects through similar mechanisms of
action. Undoubtedly, to acquire more information about the
structural requirements for the possible improvement of the
255 [M þ H]þ; IR (KBr)
n
3379, 3269, 3055, 2927, 2859, 1646, 1624,
10.32 (1H, s, NH),
1528,1321, 724 cmꢂ1; 1H NMR (300 MHz, CDCl3)
d
8.42 (1H, s, NH), 8.37 (1H, d, J ¼ 5.1 Hz, ArH), 8.13 (1H, d, J ¼ 7.8 Hz,
ArH), 8.07 (1H, d, J ¼ 5.1 Hz, ArH), 7.61e7.53 (2H, m, 2ArH), 7.30 (1H, t,

5516
C. Ma et al. / European Journal of Medicinal Chemistry 45 (2010) 5513e5519
J ¼ 7.5 Hz, ArH); 3.62 (2H, q, J ¼ 6.0 Hz, CH2), 3.03 (2H, t, J ¼ 6.0 Hz,
Anal. Calcd for C20H27IN4O: C, 51.51; H, 5.84; N, 12.01. Found: C,
51.68; H, 5.88; N, 12.12.
CH2).
5.5. 3-(b-Carboline-1-carbonyl)aminopropyl diethyl benzyl
ammonium bromide (5b)
5.2. N-(6-Aminohexyl)-b-carboline-1-carboxamide hydrochloride
salt (4b)
A mixture of 4c (0.32 g, 1.0 mmol), benzyl bromide (10 mmol)
and ethyl acetate (20 mL) was stirred under reflux for 4 h, and then
cooled, filtered and washed with ethyl ester to give yellow solid,
which could be recrystallized from ethanol, dried in vacuum to
afford yellow crystal 5b (0.41 g, 83%), mp 214e215 ꢀC. ESI-MS m/z
415 [M ꢂ Br]þ; IR (KBr) v 3292, 3034, 2974, 2905, 2821, 1667, 1628,
In a sealed microwave vial, ethyl b-carboline-1-carboxylate 3
(0.24 g, 1 mmol) and 1, 6-hexanediamine (1.16 g, 10 mmol) were
heated with stirring at 210 ꢀC under microwave irradiation for
30 min. The reaction tube was then cooled to room temperature
and the mixture was poured into H2O (100 mL) and extracted with
CH2Cl2. The organic phase was dried over anhydrous Na2SO4,
filtered and evaporated. The residue obtained was purified by silica
column chromatography with CH2Cl2/MeOH (30:1) as the eluent to
give yellow oil 4b (0.27 g, 85%). The hydrochloride salt of 4b,
prepared with dry HCl gas in MeOH, had mp 237e239 ꢀC. ESI-MS
m/z 311 [M þ H]þ; IR (KBr) v 3330, 3050, 2932, 1659, 1625, 1575,
1591, 1530, 1228, 754 cmꢂ1 1H NMR (300 MHz, DMSO-d6)
; d 11.68
(1H, s, NH), 9.22 (1H, t, J ¼ 6.0 Hz, CONH), 8.41 (1H, d, J ¼ 5.1 Hz,
ArH), 8.37 (1H, d, J ¼ 5.1 Hz, ArH), 8.27 (1H, d, J ¼ 7.8 Hz, ArH), 7.77
(1H, d, J ¼ 8.1 Hz, ArH), 7.55 (1H, t, J ¼ 7.2 Hz, ArH), 7.47 (2H, d,
J ¼ 7.2 Hz, 2ArH), 7.36e7.23 (4H, m, 4ArH), 4.48 (2H, s, NþCH2), 3.48
(2H, q, J ¼ 6.0 Hz, CH2), 3.22e3.10 (6H, m, 3CH2), 2.20e2.10 (2H, m,
CH2), 1.29 (6H, t, J ¼ 6.9 Hz, 2CH3); 13C NMR (75 MHz, DMSO-d6)
1537, 1498, 1246, 788, 753 cmꢂ1 1H NMR (300 MHz, D2O)
; d 7.72
(1H, d, J ¼ 5.7 Hz, ArH), 7.68 (1H, d, J ¼ 5.7 Hz, ArH), 7.36 (1H, d,
J ¼ 8.1 Hz, ArH), 7.23 (1H, t, J ¼ 7.8 Hz, ArH), 6.92 (1H, d, J ¼ 8.1 Hz,
ArH), 6.85 (1H, t, J ¼ 7.8 Hz, ArH), 3.22 (2H, t, J ¼ 7.2 Hz, CH2), 2.90
(2H, t, J ¼ 7.5 Hz, CH2), 1.64e1.50 (4H, m, 2CH2), 1.37e1.32 (4H, m,
d
165.9 (CO), 142.4, 136.6, 134.9, 133.2, 132.6, 131.8, 130.7, 129.8,
129.5, 128.3, 122.6, 120.6, 120.4, 118.8, 113.7, 60.8, 55.5, 53.4, 36.5,
23.1, 8.5. Anal. Calcd for C26H31BrN4O: C, 63.03; H, 6.31; N, 11.31.
Found: C, 63.23; H, 6.28; N, 11.37.
2CH2); 13C NMR (75 MHz, D2O)
d 160.7, 142.6, 134.8, 132.0, 130.1,
125.2, 121.9, 121.6, 117.9, 117.8, 112.0, 40.4, 39.7, 28.2, 27.0, 26.1, 25.6.
5.3. N-[(3-diethylamino)propyl]- -carboline-1-carboxamide (4c)
A mixture of ethyl -carboline-1-carboxylate 3 (0.24 g, 1 mmol)
5.6. N-(2-Aminoethyl)-9-(3-phenylpropyl)-b-carboline-1-
carboxamide hydrochloride salt (7a)
b
A mixture of ethyl 9-(3-phenylpropyl)-b-carboline-1-carbox-
b
ylate 6 (0.36 g, 1 mmol) and ethylenediamine (10 mL) was stirred at
room temperature for 2 h. After completion of the reaction as
indicated by TLC, the reaction mixture was evaporated under
reduced pressure and the residue was dissolved in ethyl acetate,
washed with water. The organic phase was dried over anhydrous
Na2SO4, filtered and evaporated to give the crude product, and then
washed with anhydrous ethyl ether to afford pure product 7a as
yellow solid (0.31g, 83%), mp 102e103 ꢀC. The hydrochloride salt of
7a, prepared with dry HCl gas in methanol, had mp 221e223 ꢀC.
and N, N-diethyl-1, 3-propanediamine (10 mL) was heated with
stirring to 170 ꢀC under microwave irradiation for 30 min. The
mixture was poured into H2O (100 mL) and extracted with CH2Cl2.
The organic phase was dried over anhydrous Na2SO4, filtered and
evaporated. The residue obtained was purified by silica column
chromatography with CH2Cl2/MeOH (30:1) as the eluent to give
yellow oil 4c (0.29 g, 88%). ESI-MS m/z 325 [M þ H]þ; IR (KBr)
n
3427, 3049, 2943, 2774, 1664, 1626, 1529, 1452, 1246, 753 cmꢂ1; 1H
ESI-MS m/z 373 [M þ H]þ; IR (KBr)
n
3432, 3054, 2929, 1625, 1496,
8.32 (1H, d, J ¼ 6.0 Hz,
NMR (300 MHz, CDCl3)
d 10.37 (1H, s, NH), 8.87 (1H, s, NH), 8.35
1454, 749 cmꢂ1; 1H NMR (300 MHz, D2O)
d
(1H, d, J ¼ 5.1 Hz, ArH), 8.12 (1H, d, J ¼ 7.8 Hz, ArH), 8.04 (1H, d,
J ¼ 5.1 Hz, ArH), 7.59e7.52 (2H, m, 2ArH), 7.30 (1H, td, J ¼ 6.8,1.8 Hz,
ArH), 3.62 (2H, q, J ¼ 6.3 Hz, CH2), 2.65e2.56 (6H, m, 3CH2),
1.90e1.81 (2H, m, CH2), 1.09 (6H, t, J ¼ 7.2 Hz, 2CH3). 13C NMR
ArH), 8.22 (1H, d, J ¼ 6.0 Hz, ArH), 8.10 (1H, d, J ¼ 8.1 Hz, ArH), 7.65
(1H, t, J ¼ 7.5 Hz, ArH), 7.46 (1H, t, J ¼ 7.5 Hz, ArH), 7.30 (1H, t,
J ¼ 7.5 Hz, ArH), 7.02e6.84 (5H, m, 5ArH), 4.27 (2H, t, J ¼ 7.2 Hz,
CH2), 3.61 (2H, t, J ¼ 6.3 Hz, CH2), 3.20 (2H, t, J ¼ 6.6 Hz, CH2), 2.47
(2H, t, J ¼ 7.2 Hz, CH2), 1.98e1.87 (2H, m, CH2).
(75 MHz, CDCl3) d 166.7, 141.2, 137.3, 135.6, 132.6, 131.3, 129.1, 121.9,
120.8, 120.2, 117.6, 112.1, 51.9, 47.1, 38.9, 27.0, 12.0. The hydrochlo-
ride salt of 4c, prepared with dry HCl gas in MeOH, had mp
203e205 ꢀC.
5.7. N-[(3-diethylamino)propyl]-9-(3-phenylpropyl)-b-carboline-
1-carboxamide hydrochloride salt (7b)
5.4. 3-(b-Carboline-1-carbonyl)aminopropyl diethyl methyl
ammonium iodide (5a)
A mixture of ethyl 9-(3-phenylpropyl)-b-carboline-1-carbox-
ylate 6 (0.36 g, 1 mmol) and N, N-diethyl-1, 3-propanediamine
(10 mL) was heated with stirring to 170 ꢀC under microwave irra-
diation for 30 min. The mixture was poured into H2O (100 mL) and
extracted with CH2Cl2. The organic phase was dried over anhydrous
Na2SO4, filtered and evaporated. The residue obtained was purified
by silica column chromatography with CH2Cl2/MeOH (30:1) as the
eluent to give compound 7b as yellow oil (0.36 g, 81%). The
hydrochloride salt of 7b, prepared with dry HCl gas in methanol,
had mp 201e203 ꢀC. ESI-MS m/z 443 [M þ H]þ; IR (KBr) v 3159,
A mixture of 4c (0.32 g, 1.0 mmol), methyl iodide (1 mL) and
ethyl acetate (20 mL) was stirred under reflux for 4 h, and then
cooled and filtered under reduced pressure and washed with ethyl
ester to give yellow solid, which could be recrystallized from
ethanol, dried in vacuum to afford yellow crystal 5a (0.40 g, 86%).
mp 192e193 ꢀC. ESI-MS m/z 339 [M ꢂ I]þ; IR (KBr) v 3368, 3314,
3035, 2922, 2873, 1658, 1623, 1526, 1460, 734 cmꢂ1 1H NMR
;
(300 MHz, DMSO-d6)
d
11.68 (1H, s, NH), 9.15 (1H, t, J ¼ 6.3 Hz,
CONH), 8.39 (1H, d, J ¼ 4.8 Hz, ArH), 8.34 (1H, d, J ¼ 4.8 Hz, ArH),
8.26 (1H, d, J ¼ 7.8 Hz, ArH), 7.78 (1H, d, J ¼ 8.1 Hz, ArH), 7.56 (1H, t,
J ¼ 7.5 Hz, ArH), 7.26 (1H, t, J ¼ 7.5 Hz, ArH), 4.48 (2H, s, NþCH2), 3.48
(2H, q, J ¼ 6.3 Hz, CH2), 3.32e3.26 (6H, m, 3CH2), 2.92 (3H, s, CH3),
2.06e1.96 (2H, m, CH2), 1.20 (6H, t, J ¼ 6.9 Hz, 2CH3); 13C NMR
3026, 2941, 2650, 1672, 1625, 1553, 1496, 1302, 750, 704 cmꢂ1
;
1H
NMR (300 MHz, DMSO-d6)
d
8.66 (1H, d, J ¼ 5.7 Hz, ArH), 8.52 (1H,
d, J ¼ 5.7 Hz, ArH), 8.46 (1H, d, J ¼ 8.1 Hz, ArH), 7.82e7.73 (2H, m,
2ArH), 7.41 (1H, t, J ¼ 8.1 Hz, ArH), 7.25e7.12 (5H, m, 5ArH), 4.60
(2H, t, J ¼ 7.2 Hz, CH2), 3.47 (2H, q, CH2), 3.27e3.17 (2H, m, CH2),
3.14e1.02 (4H, m, 2CH2), 2.58 (2H, t, J ¼ 7.2 Hz, CH2), 2.07e1.95 (4H,
m, 2CH2), 1.22 (6H, t, J ¼ Hz, 2CH3). 13C NMR (75 MHz, CDCl3)
(75 MHz, DMSO-d6)
d 166.4 (CO), 142.1, 137.2, 135.0, 132.9, 131.3,
129.4, 122.4, 120.5, 120.4, 118.6,113.6, 58.4, 56.4, 47.4, 36.6, 23.0, 8.3.

C. Ma et al. / European Journal of Medicinal Chemistry 45 (2010) 5513e5519
5517
d
166.9, 142.8, 141.6, 136.7, 134.6, 132.5, 129.0, 128.5, 126.1, 121.4,
ESI-MS m/z 354, 356 [M þ H]þ; 1H NMR (300 MHz, CDCl3)
d
8.23
121.1, 120.2, 116.9, 110.7, 51.9, 47.1, 45.8, 39.6, 33.4, 31.3, 26.8, 11.9.
(1H, d, J ¼ 4.8 Hz, ArH), 8.15 (1H, d, J ¼ 7.8 Hz, ArH), 7.98 (1H, d,
J ¼ 4.8 Hz, ArH), 7.58 (1H, t, J ¼ 7.8 Hz, ArH), 7.39 (1H, d, J ¼ 7.8 Hz,
ArH), 7.34 (1H, t, J ¼ 7.8 Hz, ArH), 7.08e6.93 (4H, m, 4ArH), 6.04 (2H,
s, CH2). Anal. Calcd for C18H12BrFN2: C, 60.86; H, 3.41; N, 7.89.
Found: C, 60.93; H, 3.46; N, 7.94.
5.8. 1-(2-Aminoethylamino)-
b
-carboline (11a)
-carboline 10 (0.50 g, 2.0 mmol),
A mixture of 1-bromo-
b
cuprous iodide (0.19 g, 1.0 mmol) and ethylenediamine (10 mL) was
stirred under reflux for 12 h. After completion of the reaction as
indicated by TLC, the mixture was evaporated under reduced
pressure and the residue was added H2O (50 mL) and extracted
with CH2Cl2. The organic phase was dried over anhydrous Na2SO4,
filtered and evaporated. The crude product obtained was purified
by silica column chromatography with CH2Cl2/MeOH (30:1) as the
eluent to give the target product 11a (0.28 g, 62%). The hydro-
chloride salt of 11a, prepared with dþry HCl gas in MeOH, had mp
5.12. 1-Bromo-9-perfluorobenzyl-b-carboline (12c)
A mixture of perfluorobenzyl bromide (0.31g, 1.2 mmol),
potassium iodide (0.17g, 1.0 mmol) and anhydrous DMF (10 mL)
was stirred at room temperature for 10 min, and 60% NaH (0.06 g,
1.5 mmol) was added. After 5 min, the 1-bromo-b-carboline 10
(0.25 g, 1.0 mmol) was added and stirred for 5 min. Later the
mixture was treated in a manner similar to that described for 12a
to afford pale yellow needle crystal 12c (0.36 g, 85%), mp
145e146. ESI-MS m/z 426, 428 [M þ H]þ; 1H NMR (300 MHz,
253e255 ꢀC. ESI-MS m/z 227 [M þ H] ; IR (KBr)
n
3432, 3229, 3057,
2965, 1660, 1628, 1563, 1112, 1067, 739 cmꢂ1
;
1H NMR (300 MHz,
D2O)
d
7.99 (1H, t, J ¼ 7.5 ArH), 7.51e7.47 (3H, m, 3ArH), 7.39 (1H, t,
J ¼ 7.5 Hz, ArH), 7.27 (1H, t, J ¼ 7.2 Hz, ArH), 3.81e3.73 (2H, m, CH2),
3.31 (2H, t, J ¼ 6.0 Hz, CH2).
CDCl3)
d
8.25 (1H, d, J ¼ 5.1 Hz, ArH), 8.12(1H, dt, J ¼ 7.5, 0.9 Hz,
ArH), 7.96 (1H, d, J ¼ 5.1 Hz, ArH), 7.59 (1H, td, J ¼ 7.8, 1.2 Hz,
ArH), 7.35 (2H, t, J ¼ 7.8 Hz, 2ArH), 6.35e6.27 (1H, m, CH2). Anal.
Calcd for C18H8BrF5N2: C, 50.61; H, 1.89; N, 6.56. Found: C, 50.74;
H, 1.84; N, 6.63.
5.9. 1-(2-Hydroxylethylamino)-b-carboline (11b) [9]
A mixture of 1-bromo- -carboline 10 (0.50 g, 2.0 mmol) and
b
ethanolamine (10 mL) were subjected to the same procedure
which was used to produce 11a afford the target product 11b with
56% yield. The hydrochloride salt of 11b, prepared with dryþHCl
gas in MeOH, had mp 187e189 ꢀC. ESI-MS m/z 228 [M þ H] ; IR
5.13. 1-Bromo-9-(3-phenylpropyl)-b-carboline (12d)
A mixture of 1-bromo-3-phenylpropane (0.60 g, 3.0 mmol),
potassium iodide (0.17 g, 1.0 mmol) and anhydrous DMF (10 mL)
was stirred at room temperature for 1 h, and 60% NaH (0.06 g,
(KBr)
n 3254, 3027, 2921, 2847, 1649, 1603, 1531, 1506, 1304, 1069,
753 cmꢂ1; 1H NMR (300 MHz, D2O)
d
7.36 (1H, d, J ¼ 7.8 Hz, ArH),
7.25 (1H, t, J ¼ 7.2 Hz, ArH), 7.09 (H, d, J ¼ 6.3 Hz, 2ArH),
6.96e6.90 (3H, m, 3ArH), 4.04 (2H, t, J ¼ 4.2 Hz, CH2), 3.86 (2H, t,
J ¼ 4.2 Hz, CH2).
1.5 mmol) was added. After 15 min,1-bromo-b-carboline 10 (0.25 g,
1.0 mmol) was added and stirred for 1 h. Later the mixture was
treated in a manner similar to that described for 12a to afford pale
yellow needle crystal 12d (0.34 g, 93%), mp 113e114 ꢀC. ESI-MS m/z
5.10. 1-Bromo-9-butyl-
b
-carboline (12a)
364, 366 [M þ H]þ; IR (KBr)
n
3424, 3050, 3031, 2930, 2860, 1620,
1533, 1437, 1178, 834, 748, 701 cmꢂ1
;
1H NMR (300 MHz, CDCl3)
To the solution of 1-iodobutane (0.74 g, 3.0 mmol) in anhydrous
DMF (10 mL), 60% NaH (0.08 g, 2.0 mmol) was added. The mixture
was stirred at room temperature for 10 min, and then 1-bromo-b-
d
8.18 (1H, d, J ¼ 5.1 Hz, ArH), 8.10 (1H, d, J ¼ 7.8 Hz, ArH), 7.92 (1H,
d, J ¼ 5.1 Hz, ArH), 7.59 (1H, t, J ¼ 7.5 Hz, ArH), 7.36e7.18 (7H, m,
7ArH), 4.79 (2H, t, J ¼ 7.8 Hz, CH2), 2.80 (2H, t, J ¼ 7.8 Hz, CH2),
2.56e2.48 (2H, m, CH2). Anal. Calcd for C20H17BrN2: C, 65.76; H,
4.69; N, 7.67. Found: C, 75.89; H, 4.60; N, 7.73.
carboline 10 (0.25 g, 1.0 mmol) was added and stirred for 30 min.
After completion of the reaction as indicated by TLC, the mixture
was evaporated and the residue was added H2O (50 mL) and
extracted with EA. The organic phase was washed with H2O and
brine, then dried over anhydrous Na2SO4, filtered and evaporated.
The residue obtained was purified by silica column chromatog-
raphy with ethyl acetate/petroleum ether as the eluent to give
yellow needle crystal 12a (0.28 g, 92%), mp 63e65 ꢀC. ESI-MS m/z
5.14. 1-(2-Aminoethylamino)-9-butyl-b-carboline hydrochloride
salt (13a)
A
mixture of 1-bromo-9-butyl-b-carboline 12a (0.30 g,
302, 304 [M þ H]þ; IR (KBr)
n
3440, 3058, 3034, 2982, 2956, 2926,
1.0 mmol), cuprous iodide (0.19 g, 1.0 mmol) and ethylenediamine
(2 mL) was heated with stirring at 170 ꢀC under microwave irra-
diation for 30 min. Then the mixture was added H2O (50 mL) and
extracted with dichloromethane. The organic phase was dried over
anhydrous Na2SO4, filtered and evaporated. The residue obtained
was purified by silica column chromatography with CH2Cl2/MeOH
(30:1) as the eluent to afford yellow oil 13a (0.23 g, 82%). The
hydrochloride salt of 13a, prepared with dry HCl gas in MeOH, had
2863, 1621, 1565, 1561, 1533, 1464, 1202, 745 cmꢂ1
;
1H NMR
(300 MHz, CDCl3)
d
8.18 (1H, d, J ¼ 5.1 Hz, ArH), 8.11 (1H, d,
J ¼ 7.8 Hz, ArH), 7.93 (1H, d, J ¼ 5.1 Hz, ArH), 7.63 (1H, t, J ¼ 7.5 Hz,
ArH), 7.51 (1H, d, J ¼ 8.4 Hz, ArH), 7.32 (1H, t, J ¼ 7.5 Hz, ArH), 4.78
(2H, t, J ¼ 7.8 Hz, CH2), 1.90 (2H, m, CH2), 1.53e1.46 (2H, m, CH2),
1.01 (3H, t, J ¼ 7.5 Hz, CH3). Anal. Calcd for C15H15BrN2: C, 59.42; H,
4.99; N, 9.24. Found: C, 59.62; H, 5.03; N, 9.18.
mp 224e225 ꢀC. ESI-MS m/z 283 [M þ H]þ; IR (KBr)
n 3388, 3257,
5.11. 1-Bromo-9-(4-fluorobenzyl)-
b
-carboline (12b)
2952, 2924, 2854, 1639, 1604, 1535, 1498, 1459, 1343, 754 cmꢂ1; 1H
NMR (300 MHz, DMSO-d6)
d
8.30 (1H, d, J ¼ 7.8 Hz, ArH), 8.24 (3H, s,
A mixture of 4-fluorobenzyl bromide (0.38g, 2.0 mmol), potas-
sium iodide (0.17g, 1.0 mmol) and anhydrous DMF (10 mL) was
stirred at room temperature for 10 min, and then 60% NaH (0.06 g,
NþH3), 7.89 (1H, d, J ¼ 7.8 Hz, ArH), 7.86 (1H, d, J ¼ 6.6 Hz, ArH), 7.77
(1H, d, J ¼ 6.6 Hz, ArH), 7.67 (1H, t, J ¼ 7.5 Hz, ArH), 7.35 (1H, t,
J ¼ 7.5 Hz, ArH), 4.88 (2H, t, J ¼ 6.9 Hz, NCH2), 4.07e3.98 (2H, m,
CH2), 3.24e3.15 (2H, m, CH2), 1.64e1.58 (2H, m, CH2), 1.19e1.11 (2H,
m, CH2), 0.80 (3H, t, J ¼ 7.2 Hz, CH3). 13C NMR (75 MHz, CDCl3)
1.5 mmol) was added. After 10 min, the 1-bromo-b-carboline 10
(0.25 g, 1.0 mmol) was added and stirred for 15 min. Later the
mixture was treated in a manner similar to that described for 12a to
afford pale yellow needle crystal 12b (0.32 g, 90%), mp 130e131.
d
146.8, 141.3, 136.7, 128.7, 127.2, 124.8, 122.0, 121.4, 119.5, 109.9,
106.2, 45.5, 44.2, 34.0, 30.1, 20.6, 14.3.

5518
C. Ma et al. / European Journal of Medicinal Chemistry 45 (2010) 5513e5519
5.15. 1-(2-Aminoethylamino)-9-(4-fluorobenzyl)-
b
-carboline (13b)
-carboline 12b
124.4, 122.1, 121.4, 119.6, 109.8, 106.1, 44.9, 42.3, 42.2, 33.3, 32.9,
31.6, 27.5. The hydrochloride salt of 13e, prepared with dry HCl gas
in MeOH, had mp 220e222 ꢀC.
A
mixture of 1-bromo-9-(4-fluorobenzyl)-
b
(0.36 g, 1.0 mmol) and ethylenediamine (20 mL) was subjected to
the same procedure which was used to prepare 13a afforded the
target product 13b in 65% yield. ESI-MS m/z 335 [M þ H]þ; IR (KBr)
v 3424, 3057, 2927, 2870, 1620, 1598, 1560, 1508, 1453, 741 cmꢂ1; 1H
5.19. 1-(6-Aminohexylamino)-9-(3-phenylpropyl)-b-carboline
hydrochloride salt (13f)
NMR (300 MHz, CDCl3)
d
8.07 (1H, d, J ¼ 7.8 Hz, ArH), 7.97 (1H, d,
A
mixture of 1-bromo-9-(3-phenylpropyl)-b-carboline 12d
J ¼ 5.4 Hz, ArH), 7.49 (1H, t, J ¼ 7.8 Hz, ArH), 7.38 (1H, d, J ¼ 5.4 Hz,
ArH), 7.34 (1H, d, J ¼ 8.4 Hz, ArH), 7.27 (1H, t, J ¼ 7.8 Hz, ArH),
7.15e7.10 (2H, m, 2ArH), 7.00 (2H, t, J ¼ 8.4 Hz, ArH), 5.67 (2H,
s, CH2), 4.87 (1H, s, NH), 3.46 (2H, t, J ¼ 5.1 Hz, CH2), 2.83 (2H, t,
(0.37 g, 1.0 mmol) and 1, 6-hexanediamine (1.16g, 10 mmol) was
heated with stirring at 210 ꢀC under microwave irradiation for
30 min. Then the mixture was treated in a manner similar to that
described for 13a to afford yellow oil 13f (0.23 g, 56%). The
hydrochloride salt of 13f, prepared with dþry HCl gas in MeOH, had
mp 186e188 ꢀC. ESI-MS m/z 401 [M þ H] ; IR (KBr) v 3170, 3030,
J ¼ 5.1 Hz, CH2); 13C NMR (75 MHz, CDCl3)
d 164.1,160.8,146.9,141.7,
137.5, 133.6, 129.0, 127.7, 127.7, 127.7, 125.1, 122.2, 121.5, 120.2, 116.5,
116.2, 109.6, 106.3, 47.9, 44.8, 41.5. The hydrochloride salt of 13b,
prepared with dry HCl gas in MeOH, had mp 253e255 ꢀC.
2937, 1642, 1618, 1535, 1487, 754, 700 cmꢂ1 1H NMR (300 MHz,
;
DMSO-d6)
d 13.63 (1H, s, NH), 10.60 (1H, s, NH), 8.29 (1H, d,
J ¼ 8.1 Hz, ArH), 8.25 (1H, s, NH), 7.83e7.74 (3H, m, 3ArH), 7.65 (1H,
t, J ¼ 7.8 Hz, ArH), 7.36 (1H, d, J ¼ 7.5 Hz, ArH), 7.22e7.05 (5H, m,
5ArH), 4.91 (2H, t, J ¼ 6.6 Hz, CH2), 3.86e3.80 (2H, m, CH2),
3.22e3.16 (2H, m, CH2), 2.75e2.70 (6H, m, 3CH2), 2.56 (2H, t,
J ¼ 7.8 Hz, CH2), 2.16e2.07 (2H, m, CH2), 1.98e1.90 (2H, m, CH2).
5.16. 1-(2-Aminoethylamino)-9-perfluorobenzyl-
b
-carboline (13c)
A
mixture of 1-bromo-9-perfluorobenzyl-
b
-carboline 12c
(0.43 g, 1.0 mmol) and ethylenediamine (20 mL) was subjected to
the same procedure which was used to prepare 13a afforded the
target product 13c in 37% yield. ESI-MS m/z 407 [M þ H]þ; IR (KBr) v
3303, 3036, 2971, 2914, 1637, 1532, 1504, 1464, 753 cmꢂ1; 1H NMR
5.20. Cytotoxicity assays in vitro
(300 MHz, CDCl3)
d
9.01 (1H, s, NH), 8.46 (1H, d, J ¼ 5.4 Hz, ArH),
Cytotoxicity assays in vitro were carried out using 96 microtitre
plate cultures and MTT staining according to the procedures
described by our group [22]. Briefly, cells were grown in RPMI-1640
8.12 (1H, dt, J ¼ 7.8, 0.9 Hz, ArH), 7.94 (1H, d, J ¼ 5.4 Hz, ArH),
7.62e7.60 (2H, m, 2ArH), 7.32e7.27 (1H, m, ArH), 5.53 (2H, s, CH2),
4.46 (1H, s, NH), 3.41e3.35 (2H, m, CH2), 2.89 (2H, t, J ¼ 6.0 Hz, CH2).
The hydrochloride salt of 13c, prepared with dry HCl gas in MeOH,
had mp >270 ꢀC.
medium containing 10% (v/v) fetal calf serum and 100
m
g mlꢂ1
penicillin and 100
m
g mlꢂ1 streptomycin. Cultures were propagated
at 37 ꢀC in a humidified atmosphere containing 5% CO2. Drug stock
solutions were prepared in DMSO. The final concentration of DMSO
in the growth medium was 2% (v/v) or lower, concentration without
effect on cell replication. The tumor cell line panel consisted of
gastric carcinoma (BGC823), liver carcinoma (HepG2), breast
carcinoma (MCF-7), renal carcinoma (OS-RC-2, 786-0 and 769-P),
melanoma (A375), colon carcinoma (HT-29), epidermoid carcinoma
of the nasopharynx (KB), prostate carcinoma (22RV1). In all of these
experiments, five replicate wells were used to determine each
point.
5.17. 1-(2-Aminoethylamino)-9-(3-phenylpropyl)-b-carboline
hydrochloride salt (13d)
A
mixture of 1-bromo-9-(3-phenylpropyl)-b-carboline 12d
(0.37 g, 1.0 mmol) and ethylenediamine (20 mL) was subjected to
the same procedure which was used to prepare 13a afforded the
target product 13d with 87% yield. The hydrochloride salt of 13d,
prepared with dry HCl gas in MeOH, had mp 256e258 ꢀC. ESI-MS
m/z 345 [M þ H]þ; IR (KBr)
n 3407, 3269, 3027, 2921, 2853, 1638,
1605, 1537, 1405, 1460, 1344, 752, 699 cmꢂ1 1H NMR (300 MHz,
;
Acknowledgements
DMSO-d6)
d
8.29 (1H, d, J ¼ 7.8 Hz, ArH), 8.19 (3H, s, NþH3), 7.84
(1H, d, J ¼ 5.4 Hz, ArH), 7.78e7.75 (2H, m, 2ArH), 7.65 (1H, t,
J ¼ 7.8 Hz, ArH), 7.36 (1H, t, J ¼ 7.8 Hz, ArH), 7.21e7.05 (5H, m,
5ArH), 4.91 (2H, t, J ¼ 7.2 Hz, NCH2), 4.09e4.03 (2H, m, CH2),
3.22e3.16 (2H, m, CH2), 2.56 (2H, t, J ¼ 7.2 Hz, CH2), 2.01e1.91 (2H,
This work was supported by MEGA-Project (2009ZX09103-015)
and the Science and Technology Project of Guangdong Province,
China (2009B060700048) and the Fundamental Research Funds for
the Central Universities and Xinjiang Huashidan Pharmaceutical
Co. Ltd.
m, CH2); 13C NMR (75 MHz, DMSO-d6)
d 143.6, 143.0, 141.6, 134.9,
130.4, 130.0, 128.8, 128.7, 126.4, 123.0, 122.8, 121.9, 120.9, 112.0,
107.3, 45.2, 38.2, 33.1, 32.7.
References
5.18. 1-(4-Aminobutylamino)-9-(3-phenylpropyl)-b-carboline
(13e)
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A
mixture of 1-bromo-9-(3-phenylpropyl)-b-carboline 12d
(0.37 g, 1.0 mmol) and 1, 4-diaminobutane (2 mL) was heated with
stirring at 150 ꢀC under microwave irradiation for 30 min. Then the
mixture was treated in a manner similar to that described for 13a to
afford yellow oil 13e (0.26 g, 71%). ESI-MS m/z 373 [M þ H]þ; IR
(KBr) v 3403, 3056, 3027, 2929, 2860, 1620, 1590, 1560, 1454,
740 cmꢂ1; 1H NMR (300 MHz, CDCl3)
d
8.01 (1H, d, J ¼ 7.8 Hz, ArH),
7.96 (1H, d, J ¼ 5.4 Hz, ArH), 7.47 (1H, t, J ¼ 7.8 Hz, ArH), 7.34e7.15
(8H, m, 8ArH), 4.40e4.31 (3H, m, NH, CH2), 3.47 (2H, t, J ¼ 6.9 Hz,
CH2), 2.76 (2H, t, J ¼ 6.6 Hz, CH2), 2.69 (2H, t, J ¼ 6.6 Hz, CH2),
2.20e2.10 (2H, m, CH2), 1.66e1.53 (4H, m, 2CH2); 13C NMR (75 MHz,
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d 146.5, 141.0, 140.7, 137.0, 128.9, 128.7, 128.6, 127.2, 126.6,

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