Design of?β-carboline derivatives as?DNA-targeting antitumor agents

Article abstract of DOI:10.1016/j.ejmech.2006.05.004

This research studied the structure-activity relationship of β-carboline derivatives as antitumor agents, in which 41 synthesized compounds and their cytotoxicity to tumor and normal cell lines were assayed. It was proved that substituent in position-9 of

Full text of DOI:10.1016/j.ejmech.2006.05.004

European Journal of Medicinal Chemistry 41 (2006) 1167–1179
http://france.elsevier.com/direct/ejmech
Original article
Design of β-carboline derivatives as DNA-targeting antitumor agents
Huaji Guan, Hongsheng Chen, Wenlie Peng, Yan Ma, Rihui Cao, Xiaodong Liu, Anlong Xu *
State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Therapeutic Functional Genes, Department of Biochemistry,
College of Life Sciences, Sun Yat-sen (Zhongshan) University, 135, Xin Gang Xi Road, Guangzhou 510275, China
Received in revised form 29 April 2006; accepted 5 May 2006
Available online 21 June 2006
Abstract
This research studied the structure-activity relationship of β-carboline derivatives as antitumor agents, in which 41 synthesized compounds
and their cytotoxicity to tumor and normal cell lines were assayed. It was proved that substituent in position-9 of the β-carboline ring could
reinforce the DNA intercalating ability and consequently cytotoxicity to tumor cell lines, and the amidation of amino group at the end of the
DNA targeting side chain in position-3 could cripple the DNA intercalating activity of these compounds, which resultingly initiated the cytotoxic
selectivity to tumor cell lines rather than to normal ones. Furthermore, the S and G2-M arrest induced by these compounds confirmed that they
could target DNA and lead to DNA destructions in Hela cells. In short, this study may provide a framework to design a novel antitumor drug that
could surpass Adriamycin.
©
2006 Elsevier Masson SAS. All rights reserved.
Keywords: Harmine; β-carboline; DNA intercalator; Prodrug
1
. Introduction
bit photosensitivity [14]. Thus far, series of structure modifica-
tion on β-carboline have been carried out, with an expected
enhancement either in antitumor activity or affinity to 5-HT
or benzodiazepine receptors, which could be served as an
inspiration for rational drug design in this research.
Researches on antitumor alkaloids isolated from plants have
been actively explored in the last thirty years, in which the
antitumor effect of the naturally occurring β-carboline deriva-
tives have been noticed recently after an intensive concentra-
tion on their high affinity to 5-HT [1] and benzodiazepine
receptors [2–5] that causes prominent CNS (central nervous
system) effects. As for the antitumor activity, harmine,
known as one of the β-carboline alkaloids isolated from Pega-
num harmala L., has been shown to have strong cytotoxicity to
tumor cell lines in vitro [6]. Recently it is discovered that β-
carboline derivatives may function their antitumor activity
through multiple mechanisms, such as intercalating into DNA
In the β-carboline ring system, a methyl group in position-1
is desirable to reduce the binding of the compound to the ben-
zodiazepine receptor [4,5], and among all the substituents
added to position-1 in our previous research, a methyl group
achieved the lowest IC50 to tumor cell lines [15]. The 2-sub-
stituted β-carboline derivatives might be one of the metabolic
forms of β-carboline in vivo that may lead to distinct neuro-
toxic effects [16]. A DNA targeting side chain in position-3
could reinforce the DNA intercalating ability of the compound
hence boost the cytotoxicity to tumor cell lines in vitro [7],
implying that for further chemical modification to increase
antitumor activity, position-3 would present a great potential
to be worked on. Hydrogen atoms in position-4, 5, 6, 7 and 8
are with the similar chemical activity and consequently diffi-
cult to control the substitution reaction when the cyclization of
β-carboline ring in this research underwent a Pictet–Spengler
reaction from L-tryptophan. Moreover, substituent in position-
[
9], inhibiting Topoisomerase I and II [8,9], CDK [10,11] and
IκK (IκB kinase complex) [12]. Our previous study has
demonstrated that they can downregulate Bcl-2 and upregulate
death receptor Fas without dependence on P53 [13], and exhi-
*
Corresponding author. Tel.: 86 20 8411 3655, fax: 86 20 8403 8377.
E-mail address: lssxal@mail.sysu.edu.cn (A. Xu).
0223-5234/$ - see front matter © 2006 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2006.05.004

1168
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
Scheme 1. Design and synthesis of β-carboline derivatives.
6
would impair the CDK (cyclin-dependent kinases) inhibition
intact β-carboline ring was reserved with a methyl group in
position-1 to reduce the binding to benzodiazepine receptor,
then different carboxylate or carboxamide chains were added
to position-3 in pursuit of the descent substituents in position-
3 that could perform strong cytotoxicity to tumor cell lines. In
succession, combining the substituent in position-3 obtained
above and the methyl group in position-1, different alkyl and
aryl groups were added to position-9 in order to boost the anti-
tumor activity.
activity [10]. In terms of position-7 and 9, our previous
research has demonstrated that the methoxyl group in posi-
tion-7 could bring up remarkable neurotoxicity in mice, and
substituent in position-9 could greatly enhance the antitumor
activity both in vitro and in vivo [15,17].
Here we report our further chemical modification on β-car-
boline derivatives aiming at better understanding of chemical
biology of these newly synthesized compounds. Firstly the

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1169
2
. Chemistry and biological results
puter-modeling result [7]. For the theory of isosterism, the
replacement of this amino group to hydroxyl group (Com-
pound 14) could possibly reserve the DNA targeting function
of the side chain. Then for further chemical modification,
importing substituents to position-9 to compounds 11, 13, 14
and 15 may help understanding the relationship between DNA
intercalating ability and the reinforced cytotoxicity induced by
adding groups to position-9 [17].
2
.1. Influence of the side chain in position-3 on cytotoxicity
The design and synthesis of β-carboline derivatives were
displayed as Scheme 1. Proper substituents in position-3 were
obtained based on the comparison in cytotoxicity of those 3-
substituted 1-methyl-β-carboline derivatives (Compounds 6–
1
5) listed in Table 1, in which the butyl carboxylate side
2
.2. Methyl group in position-1 does not influence cytotoxicity
chain (Compound 11) showed the lowest IC50 and was then
considered as the most appropriate substituent in position-3.
On the other hand, the side chains in position-3 of compounds
Methyl group in position-1 is supposed to hinder the com-
1
3 and 15 have been proved to be DNA targeting due to the
pound from binding to benzodiazepine receptor [4,5]. Since
substituents in position-9 can also cripple the affinity to benzo-
diazepine receptor [4,5], this methyl group might be futile after
hydrogen bonding between the amino group at the end of the
side chain and DNA bases, which was supported by the com-
Table 1
Cytotoxicity of β-carboline derivatives to tumor and normal cell lines
Comp.
IC50 (µmol/ml)
Bel7402
0.0260
>3.0
0.244
0.233
>3.0
0.114
0.496
1.96
Hela
0.0640
>3.0
0.338
0.197
2.93
C6
0.0713
>3.0
Lovo
0.0704
1.57
0.535
0.085
0.157
0.0274
0.235
0.370
0.379
0.342
0.00942
1.44
0.0607
0.225
0.244
0.0508
0.0477
0.0308
0.0114
0.00699
0.0670
0.0127
0.0204
0.00696
1.315
0.0711
>3.0
0.805
0.114
0.192
0.0941
0.00821
0.846
0.424
0.120
0.0864
0.0162
>3.0
>3.0
0.0275
0.00923
PLA801
0.0482
>3.0
0.371
0.160
>3.0
BGC823
0.0725
>3.0
0.250
0.125
2.63
HFL-1
0.0623
VSMC
0.0552
Harmine
6
7
9
0.146
0.114
0.503
0.0841
0.405
1.43
0.124
0.305
0.532
0.144
0.523
0.438
0.104
1.43
0.0204
0.0114
0.00610
0.0229
0.0432
0.0212
0.0275
0.0229
0.128
0.125
>3.0
0.366
0.0368
0.0226
0.0933
0.0671
0.322
0.383
0.150
0.0421
0.00648
>3.0
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
5
5
5
5
5
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
0.0769
0.525
0.405
0.243
0.168
0.237
0.141
0.334
0.268
0.548
0.0492
0.0158
0.00680
0.0117
0.0190
0.0339
0.0318
0.0159
0.190
0.238
0.197
>3.0
0.0335
0.0990
0.0315
0.362
0.0154
>3.0
0.332
0.706
0.0660
0.00953
>3.0
0.0874
1.38
0.0635
0.852
0.315
0.342
0.213
0.137
0.987
0.209
0.174
0.577
0.429
0.0419
0.0220
0.0402
0.0206
0.0497
0.0163
0.0313
0.0205
0.0465
0.148
>3.0
0.893
0.0638
0.0761
0.0706
0.0562
1.68
0.377
0.111
0.161
0.0265
>3.0
0.752
0.333
0.266
0.817
1.36
0.594
0.456
0.560
0.251
0.306
0.359
0.0999
>3.0
0.0160
0.0298
0.00560
0.0336
0.0138
0.0293
0.00714
0.0335
0.123
0.174
>3.0
0.109
0.108
0.0328
0.121
0.0268
>3.0
0.418
0.422
0.235
0.0191
>3.0
0.261
0.437
0.262
0.593
0.0661
0.0431
0.0597
0.0232
0.0823
0.0384
0.0346
0.0231
0.0287
0.146
>3.0
0.113
0.0570
0.146
1.14
0.0239
1.73
0.515
0.131
0.0942
0.0347
>3.0
0.0411
0.0471
0.0380
0.0380
0.0326
0.0256
>3.0
0.0354
0.00583
>3.0
0.0575
0.00989
>3.0
0.0109
0.00544
>3.0
0.0389
0.00957
>3.0
0.0376
0.0132
0.0269
0.00881
0.0821
0.0630
Bel7402, Hela, C6, Lovo, PLA801and BGC823 were chosen as tumor cell lines and HFL-1 and VSMC as normal ones.

1170
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
substituents are added to position-9. Compare the cytotoxicity
of compounds 14–16 and 15–17, Table 1 showed that the
omission of the methyl group in position-1 did not have a
strong influence on cytotoxicity, neither the solubility, suggest-
ing that this methyl group might not have a strong influence on
DNA affinity, which would be validated later in the DNA
melting temperature assay. Based on this result, 1,3,9-trisubsti-
tuted or 3,9-bisubstituted β-carboline derivatives could be
synthesized with respect that they might share similar antitu-
mor activity and affinity to benzodiazepine receptor.
32 and 33, respectively, had a stronger DNA intercalating abil-
ity than compound 13 (P < 0.005, P < 0.005, respectively),
while the benzyl group in compound 34 showed the reversed
effect (P < 0.01), suggesting that proper substituents like ethyl
and n-butyl but not benzyl groups in position-9 were favorable
for the affinity to DNA, which was reserved as the possible
reason for the enhancement in cytotoxicity induced by substi-
tuents in position-9. Nevertheless, Fig. 1 demonstrated that
compound 33 had a much stronger ability to increase the dena-
turation temperature of calf thymus DNA (CT-DNA) than 34
(P < 0.005) when they shared similar cytotoxicity to tumor cell
lines, implying that besides intercalating into DNA, these com-
pounds may have other antitumor mechanisms, such as those
mentioned in the Introduction. And the tested compounds
showed no obvious selectivity in these tumor cell lines, in
which only PLA-801 reacted relatively less sensitive, indicat-
ing that these compounds could be used as broad-spectrum
antitumor drugs. When up to 50% tumor cell lines bearing
mutant or deleted p53 gene exhibit drug resistance to the anti-
tumor drugs that are dependent on the p53 pathway, β-carbo-
line derivatives seem to work universally in respect that they
do not alter the level of P53 [13].
2
.3. Substituent in position-9 could boost cytotoxicity
by enhancing DNA intercalating ability
9
-Substituted β-carboline derivatives containing a proper
side chain in position-3 obtained in 2.1 with or without a
methyl group in position-1 might show decent antitumor activ-
ity. Following this proposal, different substituents were added
to the position-9 of compound 11, 13, 14 and 15 to boost the
cytotoxicity. Firstly, series of 9-substituted β-carboline in the
form of butyl carboxylates (compound 18–21) were synthe-
sized. Phase transfer catalysis was attempted to import a sub-
stituent to position-9, but it was found that the carboxylate
bond in position-3 was instable in the basic water phase
Different groups were added to the position-9 of compound
14. The target compounds (compound 39–48) showed strong
cytotoxicity (Table 1) but weaker than the 9-substituted β-car-
boline derivatives with a short DNA targeting side chain did
(
50% NaOH solution) in the company of a hydrolysis process
in position-3. Then the nucleophilic substitution reaction was
carried out in a less basic DMF medium. However, Table 1
(compound 32–38). Now that compound 40 and 41 also per-
formed a weaker DNA intercalating capability in the DNA
thermal denaturation assay than 32 and 33 did (P < 0.005,
P < 0.005, respectively, Fig. 1), respectively, thus, it could be
concluded that the replacement of hydroxyl group to amino
group at the end of the side chain in position-3 would lead to
a decline in the affinity to DNA and cytotoxicity. As an expla-
nation for this result, the hydroxyl group with strong electro-
negativity is prone to forming intra- or inter-molecule hydro-
gen bonding that is thermodynamically more stable than the
one with DNA base; therefore it would Jeopardize the forma-
tion of hydrogen bonding between the hydroxyl group and
DNA base and consequently the DNA intercalating ability.
This explanation was supported by the fact that the polarity
of compound 13 is stronger than 14 (detected by thin layer
chromatography at 30°C; ethyl acetate, methanol, and ethyl
acetate/methanol/glacial acid = 5:3:1 were used as the develop-
ing systems). At the same time, Fig. 1 showed that compound
(
compound 18–21) showed that substituent in position-9 did
not enhance the cytotoxicity as our previous research did [15,
7] but Jeopardized it instead, which could be accounted for a
1
decrease in the solubility of these compounds in water.
When importing alkyl or aryl groups to position-9 of com-
pound 13, some 9-substituted intermediates (compound 22–31)
were synthesized in advance [15] due to the instability of the
carboxamide bond of compound 13 in the basic DMF medium
for nucleophilic substitution reaction. Groups that added to
position-9 of compound 13 brought up much stronger cytotoxi-
city to tumor cell lines (compound 32–38, Table 1) than that
before substitution, in which both n-butyl group (compound
3
3) and benzyl group (compound 34) seemed to be favorable
for the high cytotoxicity. The DNA thermal denaturation assay
Fig. 1) showed that the ethyl and n-butyl group in compound
(
41 and 46 shared similar DNA affinity, which validated the
proposal in 2.2 that the methyl group in position-1 did not
have a strong influence on DNA intercalating ability hence
cytotoxicity. However, compound 42 completely lost the cyto-
toxicity to tumor cell lines, owing to a drastic decline in solu-
bility in water.
As for the 9-substituted β-carboline with a long DNA target-
ing side chain in position-3 (compound 49–52, Table 1), they
did not have a stronger cytotoxicity than those with a short
DNA targeting side chain (compound 32–38), indicating that
the long one did not work as well as the short one did. The
computer-modeling result has shown that β-carboline with a
Fig. 1. Effect of binding by β-carboline derivatives on the thermal stability of
the CT-DNA. *Adr is short for Adriamycin. Results were expressed as mean
±
S.D. (N = 4).

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1171
medium-length side chain (–CONHCH CH CH CH NH ) in
DNA intercalating ability than 34 did (P < 0.005, Fig. 1), sug-
gesting that the amidation successfully impair the hydrogen
bonding with DNA. However, this electronegative amino
group might endow the compound with the affinity to many
biological molecules; now that only the binding to DNA has
been proved [7], we discuss the DNA intercalating activity
here without consideration of other possible interactions
between this amino group and other biological molecules.
Compound 55 and 56 were both stable in their hydrochloride
salt solutions and showed strong cytotoxicity in Table 1, while
whether they would have a weak effect on normal cell lines
would be tested in the next step.
2
2
2
2
2
position-3 fits the DNA base plane by the square, so that the
steric hindrance between two DNA strands might constrain the
lengthening of the side chain, accordingly β-carboline with a
long DNA targeting side chain would have a decline in the
DNA intercalating ability [7], as observed in Fig. 1 that com-
pound 49 had a lower ΔTm value than compound 34
(
P < 0.005).
2
.4. Failure in hydrogen bonding could decrease DNA affinity
and cytotoxicity to normal cell lines but not tumor ones
To detect the cytotoxic selectivity of these compounds to
tumor and normal cell lines, the normal cell lines selected
were HFL-1, which has normal human genome but proliferates
as fast as tumor cell lines do, and VSMC, which is vascular
smooth muscle cells isolated from rats and barely proliferates
in vitro. Table 1 showed that compounds 32, 33 and 34 per-
formed strong cytotoxicity both to tumor and normal cell lines,
suggesting the DNA targeting side chain worked effectively in
all these cell lines. While the IC50 of the β-carboline dimers 55
and 56 to VSMC was 7.5 and 11.6 times higher than that to
C6, respectively, demonstrating that the amidation of the func-
tional amino group at the end of the DNA targeting side chain
was a practicable method to make compounds into prodrugs,
which could selectively act on tumor cells but with a weak
effect on normal cells.
Among all the synthesized compounds above, 9-substituted
β-carboline with a short DNA targeting side chain in position-3
compounds 32–38) represented the lowest IC50 to tumor cell
lines. But a problem subsequently comes as these compounds
compounds 32–34, Table 1) are also highly cytotoxic to nor-
mal cell lines (HFL-1 and VSMC). And a proposed solution
for this problem is the amidation of the amino group at the
end of the DNA targeting side chain in position-3, which was
supposed to bind to DNA base with hydrogen bonding [7]. The
amidation might lead to a decrease in the affinity of the com-
pound to DNA, but under the hydrolysis effect of amidase in
tumor cells, which is generally accepted to be more active than
the normal ones and commonly involved in prodrug design
(
(
[
18], this functional amino group could be released. As a
result, the amidation product would act as a prodrug and regain
the DNA intercalating ability in tumor cells but with a weak
effect on normal cells in theory. In terms of choosing amida-
tion agents, the preferred ones would be amino acids, because
they might involve the β-carboline molecule into the metabolic
pathway of amino acids. But when the amino acid was
imported, the free amino group that came along with amino
acid molecule might still bind to DNA base with hydrogen
bonding; therefore, as an attempt, tryptophan was introduced
as the amidation agent to prevent the hydrogen bonding
owing to the steric hindrance caused by the large indole ring
2.5. β-carboline derivatives could induce an S and G2-M
arrest in Hela cells
Results of cell cycle analysis by flow cytometry were dis-
played in Fig. 2. At the concentration of 5 µM, no clear cell
cycle arrest had occurred, but up to 78.22% and 81.04% apop-
tosis had achieved after the incubation with compound 33 for
48 and 72 hours, respectively, when our previous research has
demonstrated that β-carboline derivatives induce cell death via
apoptosis [13]. After Hela cells were treated with compound 33
for 24 hours, the G2-M arrest had been triggered (Fig. 2E).
And after treated for 48 and 72 hours, a clear G2-M arrest
could be observed (Fig. 2F, G), which could be accounted for
the DNA damage induced by compound 33 that inhibited mito-
sis. Meanwhile, a distinct S phase arrest was also observed,
which could be caused by the inhibition to Topoisomerase I
and II (our unreported data) at the beginning of DNA synthesis
(Fig. 2E). However, when compound 33 effectively interca-
lates into DNA, it might lead to the DNA structural instability
hence DNA strand breaks like Adriamycin does [19,20]; as a
result, cells that could not reach 2N genome after duplication
were negatively selected at the G2 cell cycle checkpoint due to
the inactivation of CDC-2 [21], and consequently stuck at the S
phase (Fig. 2F, G). Since β-carboline derivatives do not alter
the level of P53 [13], cells might waltz through the p53-led G1
checkpoint into the S phase [22]; after all, no obvious G0-G1
arrest was induced by compound 33. The DNA binding prop-
erty of β-carboline derivatives has been studied well in a cell-
(
compound 54). However, the hydrochloride salt solutions of
compounds 53 and 54 were found to be rather instable with a
hydrolysis process in the carboxamide bond between the amino
acid molecule and β-carboline side chain (detected by thin
layer chromatography), then the alkaloid forms of 53 and 54
were used for the drug screening. But disappointingly, both of
5
3 and 54 lost their cytotoxicity to tumor cell lines by reason
of their weak solubility in water (Table 1).
Considering that the carboxyl group in the alkyl chain of
amino acid might result in the instability of the carboxamide
bond in the hydrochloride salt solution, an aryl carboxyl group
with less chemical activity would be favorable for the amida-
tion reaction. Then the β-carboline carboxylic acids were
selected as the amidation agents to construct the dimer of β-
carboline, which contained two identical carboxamide bonds
that could be hydrolyzed into the same DNA intercalator (com-
pounds 55 and 56). The DNA thermal denaturation assay did
show that after amidation of the amino group at the end of the
side chain in position-3, compound 56 performed a weaker

1172
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
Fig. 2. Cell cycle analysis of Hela by flow cytometry. A, control; B, C and D, Cells were treated with compound 33 at the concentration of 5 µM after incubated for
4, 48 and 72 hours, respectively; E, F and G, Cells were treated with compound 33 at the concentration of 1.25 µM after incubated for 24, 48 and 72 hours,
respectively. M1, M2, M3 and M4 showed the “sub-G1”, “G0-G1”, “S” and “G2-M” peaks, respectively. Percentages of gated cells in each phase were displayed.
2
free system [7], yet it is still not convincing that it reflects the
practical situation in cells. However, this result can be evidence
that β-carboline derivatives can induce cellular response as the
consequences of compounds binding to DNA.
and the lengthening of the side chain would be constrained
by the steric hindrance between two DNA strands. However,
the amidation of this functional amino group could endow the
compound with the cytotoxic selectivity to tumor cell lines
rather than to normal ones, due to the block out of hydrogen
bonding to DNA, demonstrating that the failure in intercalating
into DNA is closely related to the cytotoxicity to normal cell
lines. While under the hydrolysis effect of amidase in tumor
cells, which is more active than that in normal cells, this
amino group can be released and regain the DNA intercalating.
Proper substituents in position-9 will reinforce the binding of
compound to DNA, increase cytotoxicity but decrease the solu-
bility in water. While in some cases like Compound 34, the
decrease in DNA intercalating ability caused by groups in posi-
tion-9 does not pull down cytotoxicity, suggesting that besides
intercalating into DNA, these compounds may function antitu-
mor activity via other mechanisms. In short, this research may
provide some new inspirations for the design of DNA interca-
lators and prodrugs.
3
. Conclusion
In the β-carboline ring, the methyl group in position-1 can
impair the binding of the compound to benzodiazepine receptor
but not the DNA intercalating ability, cytotoxicity to tumor cell
lines or solubility in water. Though the β-carboline plane alone
can intercalate into DNA with van der Waals interactions, the
short DNA targeting side chain (–CONHCH CH NH ) in posi-
2
2
2
tion-3 is responsible for the hydrogen bonding with DNA base.
Replacement of the amino group at the end of the DNA target-
ing side chain by hydroxyl group or the lengthening the side
chain would lead to a weakened cytotoxicity due to a decline in
the DNA intercalating ability, because the hydroxyl group is
prone to forming an intra- or inter-molecule hydrogen bond

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1173
4
. Experimental
1-CH ); IR (KBr): 3419, 3340, 3267, 3203, 3037, 1623,
3
–
1
1
2
498, 1349, 1254, 732 cm ; UV:λ
44, 225, 215 nm; FAB-MS (M + 1): [M + 1] calcd for
346, 333, 275, 266,
max
+
4
.1. Synthetic protocols
C H N O, 241; found 241; Analysis (calcd, found for
1
3 12 4
C H N O): C (65.0, 64.7), H (5.0, 5.4), N (23.3, 23.0).
1
3 12 4
All reagents were purchased from commercial suppliers and
dried and purified when necessary
4
(
.1.4. N-(2-aminoethyl)-1-methyl-β-carboline-3-carboxamide
13)
Ethylenediamide (18 ml, 20.3 mmol) was heated at 80~90°
C, then compound 6 (1.02 g, 4 mmol) diluted in ethanol
20 ml) was added drop-wise in 1 h. After heated for 48 h,
4
.1.1. Propyl-1-methyl-β-carboline-3-carboxylate (10)
Compound 8 (1.17 g, 5 mmol) was suspended in 1-propanol
(
50 ml), and then SOCl (4 ml) was added drop-wise under ice
2
(
bath. After refluxed for 4 h, the mixture was poured into water
200 ml) neutralized by NaHCO and extracted with ethyl acet-
the mixture was poured into water (200 ml) and extracted
with ethyl acetate (5 × 100 ml). The organic layer was dried
with anhydrous sodium sulfate, removed by evaporation and
the residue was purified by silica column chromatography
with methanol as the eluent to remove the side-product of
dimer and excess ethylenediamide. After recrystallization with
ethanol, white crystals of 13 were obtained (0.24 g, 22%). m.
p.: 198–199°C; H NMR (500 MHz, DMSO-d ): δ 8.69 (s, 1H,
4
8
(
3
ate (4 × 100 ml). The organic layer was dried with anhydrous
sodium sulfate, removed by evaporation and the residue was
recrystallized with ethanol twice. White crystals of 10 were
1
obtained (0.56 g, 42%). m.p.: 220–221°C; H NMR
(
500 MHz, DMSO-d ): δ 9.67 (s, 1H, 9-H), 8.76 (s, 1H,
6
4
-H), 8.18 (d, J = 8 Hz, 1H, 8-H), 7.62 (d, J = 8.5 Hz, 1H,
1
6
5
-H), 7.56 (m, 1H, 7-H), 7.35 (m, 1H, 6-H), 4.39 (t,
-H), 8.62 (t, J = 6 Hz, 1H, CONH), 8.35 (d, J = 8 Hz, 1H,
-H), 7.65 (d, J = 8.5 Hz, 1H, 5-H), 7.52 (m, 1H, 6-H), 7.31
J = 6.5 Hz,COCH CH CH ), 2.84 (s, 3H, 1- CH ), 1.83 (m,
2
2
3
3
2
H, COCH CH CH ), 1.02 (t, J = 7.5 Hz, 3H,
2 2 3
(m, 1H, 7-H), 3.35 (m, 2H, NHCH CH NH ), 3.07 (m, 2H,
2 2 2
COCH CH CH ); IR (KBr): 3237, 3069, 2969, 2884, 1911,
2
2
3
NHCH CH NH ), 2.82 (s, 3H, 1- CH ); IR (KBr): 3264,
2 2 2 3
3042, 2893, 1653, 1534, 1461, 1367, 1235, 752 cm ; UV:
λmax 344, 332, 298, 284, 248, 224, 212 nm; FAB-MS
(M + 1): [M + 1] calcd for C H N O, 269; found 269; Ana-
15 16 4
–
1
1
704, 1453, 1388, 1348, 1260, 972, 742 cm ; UV:λ
356,
–1
max
+
3
41, 307, 289, 249, 212 nm; FAB-MS (M + 1): [M + 1] calcd
for C H N O , 269; found 269; Analysis (calcd, found for
+
1
6
16
2
2
C H N O ): C (71.6, 71.6), H (6.0, 6.0), N (10.4, 10.4).
1
6
16
2
2
lysis (calcd, found for C H N O): C (67.2, 67.3), H (6.0,
15 16 4
5.7), N (20.9, 21.1).
4
.1.2. Butyl-1-methyl-β-carboline-3-carboxylate (11)
Prepared by the same procedure as compound 10 from 8
4.1.5. N-(2-hydroxylethyl)-1-methyl-β-carboline-3-
carboxamide (14)
A mixture of ethanolamide (8 ml, 133 mmol) and ethanol
(40 ml) was heated at 80~90°C, then compound 6 (1.02 g,
(
1.17 g, 5 mmol) and 1-butanol (50 ml). White crystals of 11
1
were obtained (0.65 g, 46%). m.p.: 168–169°C; H NMR
500 MHz, DMSO-d ): δ 9.83 (s, 1H, 9-H), 8.76 (s, 1H, 4-H),
(
8
(
6
.18 (d, J = 8 Hz, 1H, 8-H), 7.62 (d, J = 8.5 Hz, 1H, 5-H), 7.57
m, 1H, 6-H), 7.35 (m, 1H, 7-H), 4.43 (t, J = 7 Hz, COC
H CH CH CH ), 2.81 (s, 3H, 1-CH3), 1.77 (m, 2H,
4
1
mmol) diluted in ethanol (20 ml) was added drop-wise in
h. After heated for 8 h, the mixture was poured into water
2
2
2
3
(200 ml) and extracted with ethyl acetate (5 × 100 ml). The
organic layer was dried with anhydrous sodium sulfate,
removed by evaporation and the residue was recrystallized
with ethanol twice. White crystals of 14 were obtained
COCH CH CH CH ), 1.45 (m, 2H, COCH CH CH CH ),
2
2
2
3
2
2
2
3
0
3
7
.94 (t, J = 7.5 Hz, 3H, COCH CH CH CH ); IR (KBr):
2 2 2 3
236, 2957, 2870, 1698, 1624, 1503, 1461, 1346, 1248,
–
1
1
35 cm ; UV:λ
352, 338, 317, 297, 250, 225, 212 nm;
max
(0.67 g, 62%). m.p.: 198–199°C; H NMR (500 MHz, DMSO-
+
FAB-MS (M + 1): [M + 1] calcd for C H N O , 283;
d6): δ 8.68 (s, 1H, 4-H), 8.61 (t, J = 6 Hz, 1H, CONH), 8.35 (d,
J = 8Hz, 1H, 8-H), 7.64 (d, J = 8.5 Hz, 1H, 5-H), 7.58 (m, 1H,
6-H), 7.28 (m, 1H, 7-H), 4.89 (s, 1H, OH), 3.57 (m, 2H,
NHCH CH OH), 3.46 (m, 2H, NHCH CH OH), 2.50 (s, 3H,
17 18 2 2
found 283; Analysis (calcd, found for C H N O ): C (72.3,
17 18 2 2
7
2.3), H (6.4, 6.5), N (9.9, 9.8).
2
2
2
2
1
1
2
2
- CH ); IR (KBr): 3420, 3219, 2943, 1629, 1542, 1463, 1349,
4
.1.3. 1-methyl-β-carboline-3-carboxazine (12)
Compound 6 (1.02 g, 4 mmol) was diluted and boiled in
3
–
1
250, 741 cm ; UV:λ
12 nm; FAB-MS (M + 1): [M + 1] calcd for C H N O ,
346, 332, 300, 282, 247, 223,
max
+
1
5 15 3 2
ethanol (60 ml), and then hydrazine hydrate (85%, 4 ml) was
added drop-wise in 1 h. After heated for 4 h, the mixture was
poured into water (200 ml) and extracted with ethyl acetate
70; found 270; Analysis (calcd, found for C H N O ): C
1
5 15 3 2
(66.9, 66.8), H (5.6, 5.8), N (15.6, 15.5).
(
4 × 100 ml). The organic layer was dried with anhydrous
sodium sulfate, removed by evaporation and the residue was
4.1.6. N-(2-aminohexyl)-1-methyl-β-carboline-3-carboxamide
(15)
1,6-Hexanediamide (3.48 g, 30 mmol) was diluted in DMF
(30 ml) and boiled, and then compound 6 (1.016 g, 4 mmol)
diluted in DMF (10 ml) was added drop-wise in 1 h. After
heated for 48 h, the mixture was poured into water (200 ml)
recrystallized with ethanol twice. White crystals of 12 were
1
obtained (0.83 g, 86%) m.p.: 204–205°C;
H
NMR
(
500 MHz, DMSO-d ): δ 9.92 (s, 1H, 9-H), 8.82 (s, 1H,
6
4
-H), 8.17 (d, J = 8 Hz, 1H, 8-H), 7.68 (d, J = 8.5 Hz, 1H,
5
-H), 7.49 (m, 1H, 6-H), 7.32 (m, 1H, 7-H), 2.93 (s, 3H,

1174
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
and extracted with ethyl acetate (5 × 100 ml). The organic
layer was dried with anhydrous sodium sulfate, removed by
evaporation and the residue was purified by silica column chro-
matography with methanol as the eluent. After recrystallization
sodium sulfate, removed by evaporation and the residue was
recrystallized with ethanol twice. White crystals of 18 were
1
obtained (0.97 g, 82%). m.p.: 71–72°C; H NMR (500 MHz,
DMSO-d ): δ 8.78 (s, 1H, 4-H), 8.22 (d, J = 7.5 Hz, 1H, 8-H),
6
with methanol, white crystals of 15 were obtained (0.21 g,
7.62 (d, J = 8.5 Hz, 1H, 5-H), 7.58 (m, 1H, 6-H), 7.36 (m, 1H,
7-H), 4.46 (t, J = 6 Hz, 2H, COCH CH CH CH ), 3.25 (s, 3H,
1
1
9%). m.p.: 240–241°C; H NMR (500 MHz, DMSO-d ): δ
6
2
2
2
3
8
.92 (s, 1H, 4-H), 8.61 (t, J = 6 Hz, 1H, CONH), 8.35 (d,
9-CH3), 2.95 (s, 3H, 1-CH3), 1.83 (m, 2H,
J = 8 Hz, 1H, 8-H), 7.74 (d, J = 8.5 Hz, 1H, 5-H), 7.62 (m,
H, 6-H), 7.32 (m, 1H, 7-H), 3.35 (m, 2H, NHC
H (CH ) NH ), 3.00 (m, 2H, NH(CH ) CH NH ), 2.98 (s,
COCH CH CH CH ), 1.51 (m, 2H, COCH CH CH CH ),
2
2
2
3
2
2
2
3
1
1.00 (t, J = 7.5 Hz, 3H, COCH CH CH CH ); IR (KBr):
2 2 2 3
–
1
3371, 2958, 2650, 1727, 1618, 1460, 1348, 1266, 757 cm ;
2
2 5
2
2 5
2
2
3
1
1
3
H, 1- CH ), 1.55 (m, 2H, NHCH CH (CH ) NH ), 1.32–
UV:λmax 350, 336, 299, 280, 248, 227, 213 nm; FAB-MS (M
3
2
2
2 4
2
+
.38 (m, 2H, CH × 3); IR (KBr): 3339, 2932, 2854, 1645,
+ 1): [M + 1] calcd for C H N O , 297; found 297; Analy-
2
18 20 2 2
–
1
544, 1453, 1395, 1370, 1366, 1264, 722 cm ; UV:λ
sis (calcd, found for C H N O ): C (73.0, 73.0), H (6.8, 6.5),
18 20 2 2
N (9.5, 9.6).
max
44, 330, 284, 252, 226, 212 nm; FAB-MS (M + 1):
+
[
(
(
M + 1] calcd for C H N O, 325; found 325; Analysis
calcd, found for C H N O): C (70.4, 70.4), H (7.4, 7.3), N
17.3, 17.2).
19 24 4
1
9
24
4
4.1.10. Butyl-9-ethyl-1-methyl-β-carboline-3-carboxylate (19)
Prepared by the same procedure as compound 18 from 11
(1.13 g, 4 mmol), 60% NaH (0.3 g, 7.5 mmol) and iodoethane
4
.1.7. N-(2-hydroxylethyl)-β-carboline-3-carboxamide (16)
Prepared by the same procedure as compound 14 from 5
(1.6 ml, 19.2 mmol). White crystals of 19 were obtained (0.98
1
g, 79%). m.p.: 96–97°C; H NMR (500 MHz, DMSO-d ): δ
6
(
0.96 g, 4 mmol) and ethanolamide (8 ml, 133 mmol). White
8.76 (s, 1H, 4-H), 8.22 (d, J = 8 Hz, 1H, 8-H), 7.66 (m, 1H,
5-H), 7.54 (m, 1H, 6-H), 7.37 (m, 1H, 7-H), 4.70 (m, 2H, 9- C
H CH ), 4.47 (t, J = 7Hz, 2H, COCH CH CH CH ), 3.21 (s,
crystals of 16 were obtained (0.59 g, 58%). m.p.: 218–219°C;
1
H NMR (500 MHz, DMSO-d ): δ 8.89 (s, 1H, 1-H), 8.85 (s,
6
2
3
2
2
2
3
1
8
1
3
2
3
1
H, 4-H), 8.67 (t, J = 6 Hz, 1H, CONH), 8.40 (d, J = 8 Hz, 1H,
-H), 7.65 (d, J = 8 Hz, 1H, 5-H), 7.58 (m, 1H, 6-H), 7.28 (m,
H, 7-H), 4.87 (s, 1H, OH), 3.57 (m, 2H, NHCH CH OH),
3H, 1-CH ), 1.85 (m, 2H, COCH CH CH CH ), 1.53 (m, 2H,
3 2 2 2 3
COCH CH CH CH ), 1.22 (t, J = 7.5Hz, 3H, 9- CH CH ),
2
2
2
3
2
3
1.01 (t, J = 7.5 Hz, 3H, COCH CH CH CH ); IR (KBr):
2
2
2
2
2
3
.45 (m, 2H, NHCH CH OH); IR (KBr): 3314, 3210, 3056,
3438, 2960, 2601, 1728, 1620, 1557, 1452, 1381, 1344, 1240,
2
2
–
1
–1
935, 1658, 1536, 1460, 1339, 1250, 732 cm ; UV:λ
751 cm ; UV:λ
348, 335, 301, 276, 246, 227, 212 nm;
max
max
+
51, 336, 289, 283, 269, 247, 227, 215 nm; FAB-MS (M +
FAB-MS (M + 1): [M + 1] calcd for C H N O , 311;
19 22 2 2
+
): [M + 1] calcd for C H N O , 256; found 256; Analysis
found 311; Analysis (calcd, found for C H N O ): C (73.5,
19 22 2 2
1
4
13
3
2
(
(
calcd, found for C H N O ): C (65.9, 65.9), H (5.1, 5.3), N
16.5, 16.4).
73.5), H (7.1, 7.3), N (9.0, 8.9).
1
4 13 3 2
4.1.11. Butyl-9-benzyl-1-methyl-β-carboline-3-carboxylate (20)
4
.1.8. N-(2-aminohexyl)-β-carboline-3-carboxamide (17)
Prepared by the same procedure as compound 15 from 5
Prepared by the same procedure as compound 18 from 11
(1.13 g, 4 mmol), 60% NaH (0.3 g, 7.5 mmol) and benzyl
(
0.96 g, 4 mmol) and 1,6-hexanediamide (3.48 g, 30 mmol).
bromide (0.54 ml, 4.3 mmol). White crystals of 20 were
obtained (0.87 g, 58%). m.p.: 112–113°C; H NMR
1
White crystals of 17 were obtained (0.25 g, 20%). m.p.: 192–
1
1
8
7
1
93°C; H NMR (500 MHz, DMSO-d ): δ 8.99 (s, 1H, 4-H),
(500 MHz, DMSO-d ): δ 8.79 (s, 1H, 4-H), 8.24 (d,
6
6
.61 (t, J = 6 Hz, 1H, CONH), 8.35 (d, J = 8 Hz, 1H, 8-H),
.72 (d, J = 8.5 Hz, 1H, 5-H), 7.62 (m, 1H, 6-H), 7.33 (m,
H, 7-H), 3.42 (m, 2H, NHCH (CH ) NH ), 3.08 (m, 2H,
J = 7.5 Hz, 1H, 8-H), 7.58 (m, 1H, 6-H), 7.42 (d, J = 8.5 Hz,
1H, 5-H), 7.37 (m, 1H, 7-H), 7.21–7.35 (m, 5H, 9- CH C H ),
2
6
5
5.86 (s, 2H, 9-CH C H ), 4.46 (t, J = 6 Hz, 2H, COC
2
2 5
2
2 6 5
NH(CH ) CH NH ), 2.98 (s, 3H, 1- CH ), 1.55 (m, 2H,
H CH CH CH ), 2.96 (s, 3H, 1-CH ), 1.85 (m, 2H,
2 2 2 3 3
2
5
2
2
3
NHCH CH (CH ) NH ), 1.30–1.37 (m, 6H, CH ×3); IR
COCH CH CH CH ), 1.53 (m, 2H, COCH CH CH CH ),
2 2 2 3 2 2 2 3
2
2
2 4
2
2
(
1
KBr): 3342, 2924, 2854, 1650, 1533, 1450, 1385, 1370,
1.01 (t, J = 7.5 Hz, 3H, COCH CH CH CH ); IR (KBr):
2 2 2 3
–
1
365, 1254, 725 cm ; UV:λ
345, 330, 266, 230, 212 nm;
3422, 3064, 2956, 1693, 1557, 1452, 1394, 1340, 1236,
max
+
–1
FAB-MS (M + 1): [M + 1] calcd for C H N O, 311; found
3
728 cm ; UV:λ
346, 333, 303, 274, 245, 226, 211 nm;
max
1
8
22
4
+
11; Analysis (calcd, found for C H N O): C (69.7, 69.7), H
FAB-MS (M + 1): [M + 1] calcd for C H N O , 373;
24 24 2 2
1
8
22
4
(
7.1, 7.3), N (18.1, 18.2).
found 373; Analysis (calcd, found for C H N O ): C (77.4,
24 24 2 2
77.4), H (6.5, 6.8), N (7.5, 7.3).
4
.1.9. Butyl-9-methyl-1-methyl-β-carboline-3-carboxylate (18)
A mixture of 11 (1.13 g, 4 mmol) and anhydrous DMF
4.1.12. Butyl-9-(2′,3′,4′,5′,6′-pentafluoro)benzyl-1-methyl-β-
carboline-3-carboxylate (21)
(
60 ml) was stirred at room temperature until clear, and then
6
3
0% NaH (0.3 g, 7.5 mmol) and iodomethane (0.25 ml,
.75 mmol) were added. The resulting mixture was poured
Prepared by the same procedure as compound 18 from 11
(1.13 g, 4 mmol), 60% NaH (0.3 g, 7.5 mmol) and α-bromo-
2,3,4,5,6-pentafluorotoluene (0.65 ml, 4.3 mmol). White crystals
into water (200 ml) and extracted with ethyl acetate
4 × 100 ml). The organic layer was dried with anhydrous
1
(
of 21 were obtained (1.33 g, 72%). m.p.: 120–121°C; H NMR

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1175
(
500 MHz, DMSO-d ): δ 8.74 (s, 1H, 4-H), 8.20 (d, J = 8 Hz,
2H, 9-CH C H ), 3.43 (m, 2H, NHCH CH NH ), 3.34 (m,
2 6 5 2 2 2
6
1H, 8-H), 7.58 (m, 1H, 6-H), 7.42 (d, J = 8.5 Hz, 1H, 5-H), 7.37
2H, NHCH CH NH ), 2.89 (s, 3H, 1- CH ); IR (KBr): 3370,
2 2 2 3
(
m, 1H, 7-H), 6.01 (s, 2H, 9-CH C F ), 4.47 (t, J = 6 Hz, 2H,
3061, 2927, 2864, 1652, 1620, 1559, 1526, 1451, 1342,
2
6 5
–
1
COCH CH CH CH ), 3.17 (s, 3H, 1-CH ), 1.86 (m, 2H,
COCH CH CH CH ), 1.52 (m, 2H, COCH CH CH CH ),
731 cm ; UV:λ
386, 352, 339, 302, 275, 238, 206 nm;
max
2
2
2
3
3
+
FAB-MS (M + 1): [M + 1] calcd for C H N O, 359;
22 22 4
2
2
2
3
2
2
2
3
1
2
7
.02 (t, J = 7.5 Hz, 3H, COCH CH CH CH ); IR (KBr): 3425,
found 359; Analysis (calcd, found for C H N O): C (73.7,
22 22 4
73.6), H (6.1, 6.4), N (15.6, 15.4).
2
2
2
3
961, 2873, 1725, 1695, 1557, 1503, 1451, 1391, 1345, 1220,
–
1
47 cm ; UV:λ
345, 332, 303, 274, 245, 226, 211 nm;
max
+
FAB-MS (M + 1): [M + 1] calcd for C H N O F , 463;
found 463; Analysis (calcd, found for C H N O F ): C
2
4
19
2
2
5
4.1.16. N-(2-aminoethyl)-9-(2′,3′,4′,5′,6′-pentafluoro)benzyl-1-
methyl-β-carboline-3-carboxamide (35)
2
4 19 2 2 5
(62.3, 62.3), H (4.1, 4.1), N (6.1, 6.0).
Prepared by the same procedure as compound 13 from 26
(1.30 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
4
.1.13. N-(2-aminoethyl)-9-ethyl-1-methyl-β-carboline-3-
White crystals of 35 were obtained (0.31 g, 23%). m.p.: 228–
1
carboxamide (32)
229°C; H NMR (500 MHz, DMSO-d ): δ 8.99 (s, 1H, 4-H),
6
Prepared by the same procedure as compound 13 from 23
0.85 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
8.82 (d, J = 7.5 Hz, 1H, 8-H), 8.68 (t, J = 6Hz, 1H, CONH),
8.44 (d, J = 8.0 Hz, 1H, 5-H), 7.73 (m, 1H, 6-H), 7.36 (m, 1H,
7-H), 5.88 (s, 2H, 9-CH2C6F5), 3.52 (m, 2H, NHC
H CH NH ), 3.40 (m, 2H, NHCH CH NH ), 2.50 (s, 3H, 1-
(
Light yellow crystals of 32 were obtained (0.19 g, 21%). m.
1
p.: 163–165°C; H NMR (500 MHz, DMSO-d ): δ 8.68 (s,
6
2
2
2
2
2
2
1
1
7
3
H, 4-H), 8.63 (t, J = 6Hz, 1H, CONH), 8.37 (d, J = 8 Hz,
H, 8-H), 7.65 (d, J = 8.5 Hz, 1H, 5-H), 7.63 (m, 1H, 6-H),
.31 (t, J = 14.5 Hz, 1H, 7-H), 4.69 (m, 2H, 9- CH CH ),
CH ); IR (KBr): 3226, 3061, 2927, 1659, 1613, 1548, 1501,
3
–
1
1470, 1351, 1275, 754 cm ; UV:λ
202 nm; FAB-MS (M + 1): [M + 1] calcd for C H N OF ,
352, 337, 301, 277, 246,
max
+
2
3
22 17
4
5
.35 (m, 2H, NHCH CH NH ), 2.88 (s, 3H, 1- CH ), 2.76
449; found 449; Analysis (calcd, found for C H N OF ): C
22 17 4 5
2
2
2
3
(
m, 2H, NHCH CH NH ), 1.39 (m, 3H, 9- CH CH ); IR
(58.9, 58.8), H (3.8, 3.6), N (12.5, 12.3).
2
2
2
2
3
(
7
KBr): 3353, 3053, 2925, 1642, 1529, 1450, 1346, 1238,
–
1
52 cm ; UV:λ
356, 340, 304, 273, 240, 202 nm; FAB-
max
4.1.17. N-(2-aminoethyl)-9-methyl-β-carboline-3-carboxamide
(36)
+
MS (M + 1): [M + 1] calcd for C H N O, 297; found
1
7 20 4
2
97; Analysis (calcd, found for C H N O): C (68.9, 68.8),
17 20 4
Prepared by the same procedure as compound 13 from 27
H (6.8, 6.9), N (18.9, 18.6).
(1.02 g, 4 mmol) and ethylenediamide (18 ml, 20.3 mmol).
White crystals of 36 were obtained (0.23 g, 21%). m.p.: 105–
1
4
.1.14. N-(2-aminoethyl)-9-n-butyl-1-methyl-β-carboline-3-
106°C; H NMR (500 MHz, DMSO-d ): δ 9.02 (s, 1H, 1-H),
6
carboxamide (33)
8.77 (s, 1H, 4-H), 8.63 (t, J = 6Hz, 1H, CONH), 8.37 (d,
J = 8Hz, 1H, 8-H), 7.65 (d, J = 8.5Hz, 1H, 5-H), 7.62 (m,
1H, 6-H), 7.31 (t, J = 14.5Hz, 1H, 7-H), 4.15 (m, 2H, 9-C
H3), 3.56 (m, 2H, NHCH CH NH ), 3.44 (m, 2H,
Prepared by the same procedure as compound 13 from 24
(
0.93 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
Light yellow crystals of 33 were obtained (0.26 g, 27%). m.
2
2
2
1
p.: 144–145°C; H NMR (500 MHz, DMSO-d ): δ 8.67 (s,
NHCH CH NH ); IR (KBr): 3260, 3048, 2882, 1661, 1538,
2 2 2
6
–
1
1
1
1
9
3
H, 4-H), 8.63 (t, J = 6 Hz, 1H, CONH), 8.37 (d, J = 7.5 Hz,
H, 8-H), 7.75 (d, J = 8.5 Hz, 1H, 5-H), 7.63 (t, J = 15.5 Hz,
H, 6-H), 7.31 (t, J = 15Hz, 1H, 7-H), 4.63 (t, J = 7.5Hz, 2H,
- CH CH CH CH ), 3.43 (m, 2H, NHCH CH NH ), 2.89 (s,
1460, 13492, 1227, 752 cm ; UV:λ
352, 339, 303, 273,
max
+
238, 202 nm; FAB-MS (M + 1): [M + 1] calcd for
C H N O, 269; found 269; Analysis (calcd, found for
1
5 16 4
C H N O): C (67.2, 67.1), H (6.0, 5.8), N (20.9, 20.8).
15 16 4
2
2
2
3
2
2
2
H, 1- CH ), 2.77 (m, 2H, NHCH CH NH ), 1.77 (m, 2H, 9-
3
2
2
2
CH CH CH CH ), 1.39 (m, 2H, 9- CH CH CH CH ), 0.92 (t,
2
2
2
3
2
2
2
3
4.1.18. N-(2-aminoethyl)-9-ethyl-β-carboline-3-carboxamide
(37)
J = 7.5Hz, 3H, 9- CH CH CH CH ); IR (KBr): 3374, 3055,
2
2
2
3
–
1
2
960, 2865, 1644, 1521, 1452, 1352, 1249, 752 cm ; UV:
Prepared by the same procedure as compound 13 from 28
λ
356, 340, 304, 274, 240 nm; FAB-MS (M + 1): [M + 1]
max
(0.80 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
+
calcd for C H N O, 325; found 325; Analysis (calcd, found
1
9 24 4
White crystals of 37 were obtained (0.18 g, 21%). m.p.: 123–
for C H N O): C (70.2, 70.4), H (7.4, 7.8), N (17.3, 17.0).
1
1
9 24 4
1
8
24°C; H NMR (500 MHz, DMSO-d ): δ 9.02 (s, 1H, 1-H),
6
.68 (s, 1H, 4-H), 8.63 (t, J = 6 Hz, 1H, CONH), 8.36 (d,
4
.1.15. N-(2-aminoethyl)-9-benzyl-1-methyl-β-carboline-3-
J = 8Hz, 1H, 8-H), 7.65 (d, J = 8.5Hz, 1H, 5-H), 7.63 (m,
1H, 6-H), 7.32 (t, J = 14.5 Hz, 1H, 7-H), 4.72 (m, 2H, 9- C
H CH ), 3.35 (m, 2H, NHCH CH NH ), 2.83 (m, 2H,
carboxamide (34)
Prepared by the same procedure as compound 13 from 25
2
3
2
2
2
(
1.03 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
NHCH CH NH ), 1.39 (m, 3H, 9- CH CH ); IR (KBr):
2 2 2 2 3
3350, 3053, 2920, 1644, 1529, 1450, 1344, 1224, 751 cm ;
–
1
Light yellow crystals of 34 were obtained (0.26 g, 24%). m.
p.: 122–124°C; H NMR (500 MHz, DMSO-d ): δ 8.79 (s,
1
1
7
1
UV:λmax 356, 341, 304, 272, 239, 202 nm; FAB-MS (M + 1):
6
+
H, 4-H), 8.63 (t, J = 6 Hz, 1H, CONH), 8.46 (d, J = 7.5 Hz,
H, 8-H), 7.78 (d, J = 8.0 Hz, 1H, 5-H), 7.63 (m, 1H, 6-H),
.36 (m, 1H, 7-H), 7.20–7.34 (m, 5H, 9-CH C H ), 5.99 (s,
[M + 1] calcd for C H N O, 283; found 283; Analysis
1
6 18 4
(calcd, found for C H N O): C (68.1, 68.0), H (6.4, 6.2), N
1
6 18 4
(19.9, 19.8).
2
6
5

1176
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
4
(
.1.19. N-(2-aminoethyl)-9-benzyl-β-carboline-3-carboxamide
38)
Prepared by the same procedure as compound 13 from 30
0.99 g, 3 mmol) and ethylenediamide (18 ml, 20.3 mmol).
J = 6Hz, 1H, CONH), 8.36 (d, J = 8Hz, 1H, 8-H), 7.75 (d,
J = 8.5Hz, 1H, 5-H), 7.62 (m, 1H, 6-H), 7.30 (m, 1H, 7-H),
4.79 (t, J = 5.5Hz, 1H, OH), 4.64 (t, J = 8Hz, 2H, 9- C
(
H
2
CH
2H, NHCH
CH CH CH
(t, J = 7.5Hz, 3H, 9- CH
3304, 3061, 2957, 2868, 1642, 1529, 1454, 1342, 1256,
2
CH
2
CH
CH
CH
3
), 3.57 (m, 2H, NHCH
OH), 3.06 (s, 3H, 1- CH
), 1.41 (m, 2H, 9- CH CH
CH CH CH ); IR (KBr): 3386,
2
CH
), 1.77 (m, 2H, 9-
CH CH ), 0.93
2
OH), 3.45 (m,
White crystals of 38 were obtained (0.23 g, 22%). m.p.: 122–
1
8
2
2
3
1
24°C; H NMR (500 MHz, DMSO-d ): δ 9.03 (s, 1H, 1-H),
2
2
2
3
2
2
2
3
6
.87 (s, 1H, 4-H), 8.63 (t, J = 6Hz, 1H, CONH), 8.44 (d,
2
2
2
3
J = 7.5Hz, 1H, 8-H), 7.78 (d, J = 8.0Hz, 1H, 5-H), 7.63 (m,
H, 6-H), 7.31 (m, 1H, 7-H), 7.21–7.32 (m, 5H, 9-
CH C H ), 5.93 (s, 2H, 9- CH C H ), 3.43 (m, 2H, NHC
–
1
1
751 cm ; UV:λmax 356, 340, 304, 274, 264, 240, 230,
223 nm; FAB-MS (M + 1): [M + 1] calcd for C19
326; found 326; Analysis (calcd, found for C19
(70.2, 70.1), H (7.1, 6.9), N (12.9, 12.7).
+
H N
23
N
O
2
,
2
6
5
2 6 5
3
H CH NH ), 3.34 (m, 2H, NHCH CH NH ); IR (KBr):
H
23
3
O
2
): C
2
2
2
2
2
2
3
1
2
367, 3055, 2926, 2864, 1662, 1623, 1585, 1526, 1494,
–
1
462, 1333, 739, 698 cm ; UV:λ
386, 356, 341, 301,
max
+
73, 238, 206 nm; FAB-MS (M + 1): [M + 1] calcd for
4.1.23. N-(2-hydroxylethyl)-9-benzyl-1-methyl-β-carboline-3-
C H N O, 345; found 345; Analysis (calcd, found for
C H N O): C (73.3, 73.4), H (5.8, 5.6), N (16.3, 16.1).
2
1
20
4
carboxamide (42)
2
1
20
4
Prepared by the same procedure as compound 14 from 25
(1.03 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
4
.1.20. N-(2-hydroxylethyl)-9-methyl-1-methyl-β-carboline-3-
crystals of 42 were obtained (0.81 g, 75%). m.p.: 182–183°C;
1
carboxamide (39)
H NMR (500 MHz, DMSO-d ): δ 8.76 (s, 1H, 4-H), 8.56(t,
6
Prepared by the same procedure as compound 14 from 22
0.81 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
J = 6Hz, 1H, CONH), 8.39 (d, J = 7.5Hz, 1H, 8-H), 7.70 (d,
J = 8.5Hz, 1H, 5-H), 7.58 (m, 1H, 6-H), 7.34 (m, 1H, 7-H),
(
crystals of 39 were obtained (0.59 g, 69%). m.p.: 189–190°C;
7.21–7.36 (m, 5H, 9-CH
3.56 (m, 2H, NHCH
CH OH), 2.86 (s, 3H, 1- CH
3
2
C
CH
2 2
6
H
5
), 5.98 (s, 2H, 9-CH
OH), 3.45 (m, 2H, NHC
); IR (KBr): 3340, 2935,
2 6 5
C H ),
1
H NMR (500 MHz, DMSO-d ): δ 8.71 (s, 1H, 4-H), 8.63 (t,
6
J = 6Hz, 1H, CONH), 8.36 (d, J = 8Hz, 1H, 8-H), 7.75 (d,
J = 8.5Hz, 1H, 5-H), 7.65 (t, J = 7.5Hz, 1H, 6-H), 7.32 (m,
H
2
2
–
1
2871, 1635, 1533, 1453, 1348, 1205, 743 cm ; UV:λmax
1
H, 7-H), 4.21 (s, 3H, 9- CH3), 3.58 (m, 2H,
352, 338, 276, 244, 228, 212 nm; FAB-MS (M + 1): [M + 1]
+
NHCH CH OH), 3.45 (m, 2H, NHCH CH OH), 2.83 (s, 3H,
calcd for C22
found for C22
11.7).
H
21
N
3
O
2
, 360; found 360; Analysis (calcd,
H N O ): C (73.5, 73.5), H (5.8, 5.9), N (11.7,
21 3 2
2
2
2
2
1
1
2
2
- CH ); IR (KBr): 3356, 2930, 2862, 1635, 1538, 1458, 1368,
337, 1279, 751 cm ; UV:λ
13 nm; FAB-MS (M + 1): [M + 1] calcd for C H N O ,
84; found 284; Analysis (calcd, found for C H N O ): C
3
–
1
352, 338, 289, 248, 220,
max
+
1
6 17 3 2
1
6
17
3
2
4.1.24. N-(2-hydroxyl)-9-(2′,3′,4′,5′,6′-pentafluoro)benzyl-1-
methyl-β-carboline-3-carboxamide (43)
(
67.8, 67.7), H (6.0, 5.8), N (14.8, 14.7).
Prepared by the same procedure as compound 14 from 26
(1.30 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
4
.1.21. N-(2-hydroxylethyl)-9-ethyl-1-methyl-β-carboline-3-
carboxamide (40)
crystals of 43 were obtained (1.02 g, 76%). m.p.: 212–213°C;
H NMR (500 MHz, DMSO-d ): δ 8.71 (s, 1H, 4-H), 8.59 (t,
6
1
Prepared by the same procedure as compound 14 from 23
(
0.85 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
J = 6Hz, 1H, CONH), 8.39 (d, J = 7.5Hz, 1H, 8-H), 7.61 m,
crystals of 40 were obtained (0.64 g, 72%). m.p.: 174–175°C;
1H, 5-H), 7.57 (m, 1H, 6-H), 7.34 (m, 1H, 7-H), 5.97 (s, 2H,
1
H NMR (500 MHz, DMSO-d ): δ 8.71 (s, 1H, 4-H), 8.63 (t,
9-CH
NHCH
2
C
6
F
5
), 3.58 (m, 2H, NHCH OH), 3.45 (m, 2H,
CH OH), 3.05 (s, 3H, 1- CH ); IR (KBr): 3332,
3
2
CH
2
6
J = 6Hz, 1H, CONH), 8.36 (d, J = 8Hz, 1H, 8-H), 7.75 (d,
J = 8.5Hz, 1H, 5-H), 7.65 (t, J = 7.5Hz, 1H, 6-H), 7.32 (m,
2
2
–
1
2944, 1653, 1548, 1507, 1453, 1342, 1297, 1020, 748 cm ;
1
H, 7-H), 4.72(m, 2H, 9- CH CH ), 3.57 (m, 2H,
UV:λmax 352, 338, 276, 243, 228, 202 nm; FAB-MS (M + 1):
2
3
+
NHCH CH OH), 3.45 (m, 2H, NHCH CH OH), 2.83 (s, 3H,
[M + 1] calcd for C22
H
16
N
O
3
O
2
F
5
, 450; found 450; Analysis
F ): C (58.8, 58.8), H (3.6, 3.4),
5
2
2
2
2
1
- CH ), 1.39 (t, J = 6Hz, 3H, 9- CH CH ); IR (KBr): 3396,
(calcd, found for C22
N (9.4, 9.5).
H
16
N
3
2
3
2
3
–
1
2
933, 2875, 1647, 1534, 1453, 1375, 1340, 1231, 753 cm ;
UV:λmax 352, 339, 276, 248, 220, 202 nm; FAB-MS (M + 1):
+
[
(
M + 1] calcd for C H N O , 298; found 298; Analysis
17 19 3 2
4.1.25. N-(2-hydroxylethyl)-9-methyl-β-carboline-3-
carboxamide (44)
calcd, found for C H N O ): C (68.7, 68.7), H (6.4, 6.2),
17 19 3 2
N (14.1, 14.2).
Prepared by the same procedure as compound 14 from 27
(1.02 g, 4 mmol) and ethanolamide (8 ml, 133 mmol). White
4
.1.22. N-(2-hydroxylethyl)-9-n-butyl-1-methyl-β-carboline-3-
crystals of 44 were obtained (0.80 g, 74%). m.p.: 162–163°C;
1
carboxamide (41)
H NMR (500 MHz, DMSO-d ): δ 9.03 (s, 1H, 1-H), 8.85 (s,
6
Prepared by the same procedure as compound 14 from 24
0.93 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
crystals of 41 were obtained (0.70 g, 72%). m.p.: 126–127°C;
1H, 4-H), 8.64 (t, J = 6Hz, 1H, CONH), 8.42 (d, J = 8Hz, 1H,
8-H), 7.75 (d, J = 8.5Hz, 1H, 5-H), 7.67 (m, 1H, 6-H), 7.34 (m,
1H, 7-H), 4.79 (t, J = 5.5Hz, 1H, OH), 4.05 (s, 3H, 9- CH3),
3.57 (m, 2H, NHCH CH OH), 3.44 (m, 2H, NHCH CH OH);
(
1
H NMR (500 MHz, DMSO-d ): δ 8.68 (s, 1H, 4-H), 8.57 (t,
6
2
2
2
2

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1177
IR (KBr): 3380, 2924, 2855, 1666, 1602, 1542, 1466, 1431,
346; found 346; Analysis (calcd, found for C H N O ): C
21 19 3 2
(73.0, 73.1), H (5.5, 5.8), N (12.2, 12.0).
–
1
1
378, 1263, 750 cm ; UV:λ
358, 342, 277, 260, 248,
max
+
2
24, 214 nm; FAB-MS (M + 1): [M + 1] calcd for
C H N O , 270; found 270; Analysis (calcd, found for
1
5 15 3 2
4
.1.29. N-(2-hydroxyl)-9-(2′,3′,4′,5′,6′-pentafluoro)benzyl -β-
C H N O ): C (66.9, 66.8), H (4.1, 4.4), N (15.6, 15.4).
1
5 15 3 2
carboline-3-carboxamide (48)
Prepared by the same procedure as compound 14 from 31
1.26 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
crystals of 48 were obtained (1.02 g, 78%). m.p.: 216–218°C;
4
(
.1.26. N-(2-hydroxylethyl)-9-ethyl-β-carboline-3-carboxamide
45)
Prepared by the same procedure as compound 14 from 28
0.80 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
(
1
H NMR (500 MHz, DMSO-d ): δ 9.07 (s, 1H, 1-H), 8.86 (s,
6
(
1H, 4-H), 8.68(t, J = 6Hz, 1H, CONH), 8.43 (d, J = 7.5Hz, 1H,
8-H), 7.73 (m, 1H, 5-H), 7.67 (m, 1H, 6-H), 7.35 (m, 1H, 7-H),
5.83 (s, 2H, 9-CH2C6F5), 3.57 (m, 2H, NHCH CH OH), 3.41
crystals of 45 were obtained (0.65 g, 77%). m.p.: 214–216°C;
1
H NMR (500 MHz, DMSO-d ): δ 9.03 (s, 1H, 1-H), 8.85 (s,
6
2
2
1
8
1
H, 4-H), 8.63 (t, J = 6Hz, 1H, CONH), 8.42 (d, J = 8Hz, 1H,
-H), 7.73 (d, J = 8.5Hz, 1H, 5-H), 7.67 (m, 1H, 6-H), 7.33 (m,
H, 7-H), 4.92 (t, J = 5.5Hz, 1H, OH), 4.72(m, 2H, 9- C
(m, 2H, NHCH CH OH); IR (KBr): 3340, 2930, 2875, 1658,
2 2
–
1
1538, 1500, 1464, 1334, 1269, 1064, 1014, 746 cm ; UV:λ
max
352, 338, 268, 256, 246, 225, 212 nm; FAB-MS (M + 1): [M +
+
H CH ), 3.56 (m, 2H, NHCH CH OH), 3.44 (m, 2H, NHC
1] calcd for C H N O F , 436; found 436; Analysis (calcd,
2
3
2
2
21 14 3 2 5
H CH OH), 1.39 (t, J = 6Hz, 3H, 9- CH CH ); IR (KBr):
found for C H N O F ): C (57.9, 58.0), H (3.2, 3.4), N (9.7,
21 14 3 2 5
2
2
2
3
3
7
326, 2928, 2851, 1627, 1575, 1534, 1466, 1438, 1312, 1244,
9.5).
.1.30. N-(2-aminohexyl)-9-benzyl-1-methyl-β-carboline-3-
–
1
50 cm ; UV:λ
356, 341, 277, 248, 222, 202 nm; FAB-MS
max
+
(
M + 1): [M + 1] calcd for C H N O , 284; found 284;
16 17 3 2
4
Analysis (calcd, found for C H N O ): C (67.8, 67.7), H
1
6 17 3 2
carboxamide (49)
(
6.0, 5.8), N (14.8, 14.7).
Prepared by the same procedure as compound 15 from 25
(
1.03 g, 3 mmol) and 1,6-hexanediamide (3.48 g, 30 mmol).
4
.1.27. N-(2-hydroxylethyl)-9-n-butyl-β-carboline-3-
Light yellow crystals of 49 were obtained (0.22 g, 18%). m.p.:
9
1
carboxamide (46)
6–97°C; H NMR (500 MHz, DMSO-d ): δ 8.73 (s, 1H, 4-
6
Prepared by the same procedure as compound 14 from 29
H), 8.53 (t, J = 6Hz, 1H, CONH), 8.42 (d, J = 7.5Hz, 1H, 8-H),
7.69 (d, J = 8.5Hz, 1H, 5-H), 7.60 (m, 1H, 6-H), 7.34 (m, 1H,
7-H), 7.21–7.33 (m, 5H, 9-CH C H ), 5.97 (s, 2H, 9-C
(
0.89 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
1
crystals of 46 were obtained (0.63 g, 68%). m.p.: 96–97°C; H
2
6
5
NMR (500 MHz, DMSO-d ): δ 9.05 (s, 1H, 1-H), 8.84 (s, 1H,
H C H ), 3.35 (m, 2H, NHCH (CH ) NH ), 3.00 (m, 2H,
2 6 5 2 2 5 2
6
4
-H), 8.62 (t, J = 6Hz, 1H, CONH), 8.41 (d, J = 8Hz, 1H, 8-
H), 7.76 (d, J = 8.5Hz, 1H, 5-H), 7.65 (m, 1H, 6-H), 7.33 (m,
H, 7-H), 4.80 (t, J = 5.5Hz, 1H, OH), 4.57 (t, J = 8Hz, 2H, 9-
CH CH CH CH ), 3.57 (m, 2H, NHCH CH OH), 3.45 (m,
NH(CH ) CH NH ), 2.98 (s, 3H, 1- CH ), 1.55 (m, 2H,
2 5 2 2 3
NHCH CH (CH ) NH ), 1.33–1.38 (m, 6H, CH ×3); IR
2
2
2
3
2
2
1
(KBr): 3296, 3061, 2928, 2854, 1649, 1620, 1559, 1528,
–
1
1453, 1370, 1342, 1206, 729 cm ; UV:λ 352, 339, 309,
max
2
2
2
3
2
2
2
1
H, NHCH CH OH), 1.82 (m, 2H, 9- CH CH CH CH ),
297, 286, 275, 265, 253, 211 nm; FAB-MS (M + 1):
2
2
2
2
2
3
+
.30 (m, 2H, 9- CH CH CH CH ), 0.88 (t, J = 7.5Hz, 3H, 9-
[M + 1] calcd for C H N O, 436; found 436; Analysis
2
2
2
3
26 30 4
CH CH CH CH ); IR (KBr): 3377, 3056, 2957, 2871, 1651,
(calcd, found for C H N O): C (75.4, 75.4), H (7.3, 7.0), N
26 30 4
(13.5, 13.4).
2
2
2
3
–
1
1
3
1
533, 1497, 1464, 1359, 1334, 1264, 750 cm ; UV:λ
359,
max
45, 292, 267, 255, 250, 225, 214 nm; FAB-MS (M + 1): [M +
+
] calcd for C H N O , 312; found 312; Analysis (calcd,
1
8 21 3 2
4
(
.1.31. N-(2-aminohexyl)-9-methyl-β-carboline-3-carboxamide
50)
Prepared by the same procedure as compound 15 from 27
1.02 g, 4 mmol) and 1,6-hexanediamide (3.48 g, 30 mmol).
found for C H N O ): C (69.5, 69.3), H (6.8, 7.1), N (13.5,
1
8 21 3 2
1
3.3).
(
4
.1.28. N-(2-hydroxylethyl)-9-benzyl-β-carboline-3-
Light yellow crystals of 50 were obtained (0.27 g, 21%). m.p.:
1
carboxamide (47)
1
67–168°C; H NMR (500 MHz, DMSO-d ): δ 8.73 (s, 1H, 4-
6
Prepared by the same procedure as compound 14 from 30
0.99 g, 3 mmol) and ethanolamide (8 ml, 133 mmol). White
crystals of 47 were obtained (0.73 g, 71%). m.p.: 210–211°C;
H), 8.53 (t, J = 6Hz, 1H, CONH), 8.42 (d, J = 7.5Hz, 1H, 8-H),
7.69 (d, J = 8.5Hz, 1H, 5-H), 7.60 (m, 1H, 6-H), 7.34 (m, 1H,
7-H), 7.21–7.33 (m, 5H, 9-CH C H ), 5.97 (s, 2H, 9-C
(
2
6
5
1
H NMR (500 MHz, DMSO-d ): δ 9.02 (s, 1H, 1-H), 8.77 (s,
H C H ), 3.35 (m, 2H, NHCH (CH ) NH ), 3.00 (m, 2H, NH
2 6 5 2 2 5 2
6
1
8
1
H, 4-H), 8.56(t, J = 6Hz, 1H, CONH), 8.38 (d, J = 7.5Hz, 1H,
-H), 7.70 (d, J = 8.5Hz, 1H, 5-H), 7.56 (m, 1H, 6-H), 7.33 (m,
H, 7-H), 7.20–7.38 (m, 5H, 9-CH C H ), 5.89 (s, 2H, 9-C
(CH ) CH NH ), 2.98 (s, 3H, 1- CH ), 1.55 (m, 2H,
2 5 2 2 3
NHCH CH (CH ) NH ), 1.33–1.38 (m, 6H, CH × 3); IR
2
2
2
3
2
2
(KBr): 3397, 2932, 1612, 1564, 1508, 1480, 1397, 1336, 1137,
2
6
5
–
1
H C H ), 3.56 (m, 2H, NHCH CH OH), 3.45 (m, 2H, NHC
H CH OH); IR (KBr): 3332, 2932, 2853, 1631, 1551, 1456,
734 cm ; UV:λ
360, 341, 309, 286, 274, 246, 204 nm;
max
2
6
5
2
2
+
FAB-MS (M + 1): [M + 1] calcd for C H N O, 325;
19 24 4
2
2
–
1
1
366, 1222, 749 cm ; UV:λ
359, 345, 291, 249, 223,
found 325; Analysis (calcd, found for C H N O): C (70.4,
19 24 4
70.2), H (7.4, 7.7), N (17.3, 17.1).
max
+
2
12 nm; FAB-MS (M + 1): [M + 1] calcd for C H N O ,
2
1 19 3 2

1178
H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
+
4
(
.1.32. N-(2-aminohexyl)-9-ethyl-β-carboline-3-carboxamide
51)
Prepared by the same procedure as compound 15 from 28
0.80 g, 3 mmol) and 1,6-hexanediamide (3.48 g, 30 mmol).
1): [M + 1] calcd for C H N O , 402; found 402; Analysis
2
3 23 5 2
(calcd, found for C H N O ): C (68.8, 68.9), H (5.7, 5.6), N
23 23 5 2
(17.5, 17.7).
(
Light yellow crystals of 51 were obtained (0.20 g, 20%). m.p.:
4.1.35. (2-(N-9-benzyl-β-carboline-3-carboxyl)amino)ethyl-
tryptophan amide (54)
1
1
46–148°C; H NMR (500 MHz, DMSO-d ): δ 9.05 (s, 1H, 1-
6
Prepared by the same procedure as compound 53 from 38
H), 8.77 (s, 1H, 4-H), 8.52 (t, J = 6Hz, 1H, CONH), 8.41 (d,
J = 7.5Hz, 1H, 8-H), 7.69 (d, J = 8.5Hz, 1H, 5-H), 7.61 (m,
(1.03 g, 3 mmol) and tryptophan (0.61 g, 3 mmol). White crys-
1
tals of m were obtained (0.25 g, 16%). m.p.: 178–179°C; H
NMR (500 MHz, DMSO-d ): δ 9.06 (s, 1H, 1-H), 8.86 (s, 1H,
1
H, 6-H), 7.32 (m, 1H, 7-H), 4.66 (s, 3H, 9- CH CH ), 3.35
2 3
(
m, 2H, NHCH (CH ) 5NH2), 3.03 (m, 2H, NH
6
2
2
4
-H), 8.75 (t, J = 6Hz, 1H, NHCH CH NHOCCH), 8.43 (d,
(
CH ) CH NH ), 1.52 (m, 2H, NHCH CH (CH ) CH NH ),
2 2
2
5
2
2
2
2
2
3
2
2
J = 8.5Hz, 1H, 8-H), 8.08 (t, J = 5Hz, 1H, NHCH CH NH
1
.41 (t, J = 6Hz, 3H, 9- CH CH ). 1.32–1.36 (m, 6H, CH ×3);
2
2
2
3
2
OCCH), 7.90–8.03 (m, 5H, 2′,3′,4′,5′,6′-H), 7.77 (d,
J = 8.5Hz, 1H, 5-H), 7.62 (m, 1H, 6-H), 7.34 (m, 1H, 7-H),
IR (KBr): 3342, 2937, 2854, 1645, 1454, 1395, 1371, 1319,
–
1
1
2
3
286, 710 cm ; UV:λ
04 nm; FAB-MS (M + 1): [M + 1] calcd for C H N O,
39; found 339; Analysis (calcd, found for C H N O): C
360, 341, 305, 289, 274, 245,
max
+
7.21–7.30 (m, 5H, 9-CH
4.03 (m, 1H, NHCH CH
CH NHOCCH), 3.32 (m, 2H, NHCH
.89 (d, J = 8Hz, 2H, NHCH CH NHOCCHCH ); IR (KBr):
C
H
), 5.84 (s, 2H, 9-CH
NHOCCH), 3.44 (m, 2H, NHC
CH NHOCCH),
C H ),
2
0 26 4
2
6
5
2 6 5
2
0 26 4
2
2
(
71.0, 70.9), H (7.7, 7.4), N (16.6, 16.3).
H
2
2
2
2
2
2
2
2
4
.1.33. N-(2-aminohexyl)-9-benzyl-β-carboline-3-carboxamide
3469, 3315, 3055, 2941, 2893, 1670, 1642, 1528, 1496, 1463,
–
1
(
52)
Prepared by the same procedure as compound 15 from 30
0.99 g, 3 mmol) and 1,6-hexanediamide (3.48 g, 30 mmol).
1390, 1333, 1264, 738 cm ; UV:λ
259, 252, 231, 226, 213 nm; FAB-MS (M + 1): [M + 1] calcd
for C H N O , 531; found 531; Analysis (calcd, found for
356, 342, 304, 279, 265,
max
+
(
3
2 30 6 2
White crystals of 52 were obtained (0.23 g, 19%). m.p.: 162–
C H N O ): C (72.5, 72.5), H (5.7, 5.5), N (15.8, 15.8).
32 30 6 2
1
1
8
64°C; H NMR (500 MHz, DMSO-d ): δ 9.03 (s, 1H, 1-H),
.74 (s, 1H, 4-H), 8.53 (t, J = 6Hz, 1H, CONH), 8.41 (d,
6
4.1.36. N,N′-bis (9-ethyl-1-methyl-β-carboline-3-carboxyl)-1,
6-diaminohexane (55)
J = 7.5Hz, 1H, 8-H), 7.69 (d, J = 8.5Hz, 1H, 5-H), 7.58 (m,
H, 6-H), 7.34 (m, 1H, 7-H), 7.21–7.36 (m, 5H, 9-
CH C H ), 5.89 (s, 2H, 9-CH2C6H5), 3.35 (m, 2H, NHC
1
1,6-Hexanediamide (1.39 g, 12 mmol) was diluted in DMF
(30 ml) and boiled, and then compound 22 (0.81 g, 3 mmol)
was added drop-wise in 1 h. After heated for 48 h, the mixture
was poured into water (200 ml) and extracted with ethyl acet-
ate (5 × 100 ml). The organic layer was dried with anhydrous
sodium sulfate, removed by evaporation and the residue was
purified by silica column chromatography with methanol as
the eluent. After recrystallization with methanol, Light yellow
2
6
5
H (CH ) NH ), 3.03 (m, 2H, NH(CH ) CH NH ), 1.53 (m,
2
2 5
2
2 5
2
2
2
H, NHCH CH (CH ) NH ), 1.32–1.37 (m, 6H, CH ×3); IR
2 2 2 3 2 2
(
1
KBr): 3295, 3054, 2932, 1646, 1559, 1534, 1453, 1382, 1342,
–
1
206, 730 cm ; UV:λ
360, 344, 290, 250, 202 nm; FAB-
max
+
MS (M + 1): [M + 1] calcd for C H N O, 401; found 401;
2
5 28 4
Analysis (calcd, found for C H N O): C (75.0, 75.1), H (7.0,
2
5 28 4
6
.6), N (14.0, 13.8).
crystals of 55 were obtained (0.21 g, 24%). m.p.: 143–145°C;
1
H NMR (500 MHz, DMSO-d ): δ 8.67 (s, 2H, 4-H), 8.55 (t,
6
4
.1.34. (2-(N-9-benzyl-β-carboline-3-carboxyl)amino)ethyl-
J = 6Hz, 2H, CONH), 8.36 (d, J = 8Hz, 2H, 8-H), 7.75 (d,
J = 8.5Hz, 2H, 5-H), 7.64 (m, 2H, 6-H), 7.31 (m, 2H, 7-H),
glycine amide (53)
Compound 38 (1.03 g, 3 mmol) was diluted and boiled in
ethanol (50 ml), and then glycine (0.23 g, 3 mmol) diluted in
ethanol (10 ml) was added drop-wise in 1 hour. After heated for
another 2 hour at 90°C, the mixture was poured into water
4
3
.69 (s, 4H, 9- CH CH ), 3.36 (m, 4H, CONHCH CH CH ),
2 3 2 2 2
.06 (s, 6H, 1- CH ), 1.57 (m, 4H, CONHCH CH CH ), 1.43
3
2
2
2
(m, 4H, CONHCH CH CH ), 1.38 (t, J = 7Hz, 6H, 9-
2 2 2
CH CH ); IR (KBr): 3290, 3049, 2932, 2857, 1682, 1651,
2
3
–
1
(200 ml) and extracted with ethyl acetate (5 × 100 ml). The
1
3
1
527, 1449, 1377, 1334, 1235, 751 cm ; UV:λ
354, 340,
max
organic layer was dried with anhydrous sodium sulfate,
removed by evaporation and the residue was purified by silica
column chromatography with methanol as the eluent to remove
the side-product of dimmer and excess ethylenediamide. After
recrystallization with methanol twice, white crystals of 53 were
08, 294, 288, 276, 250, 224, 213 nm; FAB-MS (M + 1): [M +
+
] calcd for C H N O , 589; found 589; Analysis (calcd,
3
6 40 6 2
found for C H N O ): C (73.5, 73.4), H (6.8, 7.1), N (14.3,
3
6 40 6 2
14.4).
1
obtained (0.14 g, 12%). m.p.: 171–172°C; H NMR (500 MHz,
4.1.37. N,N′-bis (9-benzyl-1-methyl-β-carboline-3-carboxyl)-1,
2-diaminoethane (56)
DMSO-d ): δ 9.07 (s, 1H, 1-H), 8.87 (s, 1H, 4-H), 8.76 (t,
6
J = 6Hz, 1H, CONH), 8.44 (d, J = 8.5Hz, 1H, 8-H), 7.78 (d,
J = 8.5Hz, 1H, 5-H), 7.63 (m, 1H, 6-H), 7.46 (m, 1H, 7-H),
Prepared by the similar procedure as compound 55 from 25
(1.03 g, 3 mmol) and ethylenediamide (7.1 ml, 8 mmol) except
that DMF was replaced by ethanol. Light yellow crystals of 56
7
4
.20–7.30 (m, 5H, 9-CH C H ), 5.85 (s, 2H, 9-CH C H ),
2 6 5 2 6 5
1
.29 (t, J = 4.29Hz, 2H, NHCH CH NHOCCH NH ), 3.44
were obtained (0.22 g, 22%). m.p.: 210–211°C; H NMR
2
2
2
2
(
m, 2H, NHCH CH NHOCCH NH ), 3.31 (m, 2H,
(500 MHz, DMSO-d ): δ 8.75 (s, 2H, 4-H), 8.71 (t,
2
2
2
2
6
NHCH CH NHOCCH NH ); IR (KBr): 3468, 3237, 3054,
J = 5.5Hz, 2H, CONH), 8.43 (d, J = 7.5Hz, 2H, 8-H), 7.70
(d, J = 8.0Hz, 2H, 5-H), 7.60 (m, 2H, 6-H), 7.34 (m, 2H, 7-
H), 7.21–7.35 (m, 10H, 9-CH C H ), 5.98 (s, 4H, 9-C
2
2
2
2
2
7
946, 2868, 1672, 1644, 1544, 1495, 1464, 1394, 1353, 1264,
–
1
40 cm ; UV:λ
357, 342, 273, 245, 205 nm; FAB-MS (M +
max
2
6
5

H. Guan et al. / European Journal of Medicinal Chemistry 41 (2006) 1167–1179
1179
H C H ), 3.45 (m, 4H, NHCH CH NH), 2.88 (s, 6H, 1- CH );
ethanol for 12 hours. After ethanol was removed, cells were
2
6
5
2
2
3
–
1
IR (KBr): 3286, 3060, 2939, 2840, 1695, 1651, 1449, 1379,
stained with 50 µg ml
10 mg ml RNase A) and analyzed by flow cytometry with
10,000 cells counted.
propidium iodide (containing
–
1
–1
1
342, 1270, 1204, 727 cm ; UV:λ
352, 339, 302,
max
2
87, 275, 264, 256, 245, 222, 213 nm; FAB-MS (M + 1):
+
[
M + 1] calcd for C H N O , 657; found 657; Analysis
42 36 6 2
Acknowledgements
(
calcd, found for C H N O ): C (76.8, 76.6), H (5.5, 5.8),
42 36 6 2
N (12.8, 13.0).
We acknowledge the financial support from Xinjiang Hua-
shidan Pharmaceutical Co. Ltd. We also thank Center for Ana-
lysis & Test of Sun Yat-sen (Zhongshan) University for UV,
4
.2. Cell culture
1
Cell lines were cultured in plastic culture flasks (Life Tech-
FAB-MS, IR and H NMR spectra. This work was supported
nologies) with RPMI 1640 medium (Life Technology) supple-
mented with 10% fetal bovine serum (HyClone Co.),
by grants from the National New Drug Fund for Doctors (96-
901-06-36) of the Ministry of Science & Technology, the Nat-
ural Science Foundation (027-413046) and Guangzhou Com-
mission of Science and Technology (97-Z-12-01).
–
1
–1
1
00 U ml of penicillin, and 100 μl ml of streptomycin in
a humidified atmosphere of 5% CO /95% air at and given fresh
2
medium every 3 or 4 days.
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.3. In vitro cellular proliferation inhibition assay
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