Synthesis and biological evaluation of novel β-carbolines as potent cytotoxic and DNA intercalating agents

Article abstract of DOI:10.1248/cpb.58.901

A series of novel water-soluble β-carbolines bearing a flexible amino side chain was designed, synthesized and evaluated as potent cytotoxic and DNA intercatalating agents. The N⁹-arylated alkyl substituted β-carbolines represented the most interesting cytotoxic activities. The results suggested that (1) the N⁹-arylated alkyl substituents of β-carboline nucleus played a very important role in the modulation of the cytotoxic potencies; (2) the length of the alkylamino side chain significantly affected their cytotoxic potency, and N,N-dimethylaminopropylamino substituent were more favorable. In addition, these compounds were found to exhibit significant DNA intercalating potencies.

Full text of DOI:10.1248/cpb.58.901

July 2010
Regular Article
Chem. Pharm. Bull. 58(7) 901—907 (2010)
901
b
Synthesis and Biological Evaluation of Novel -Carbolines as Potent
Cytotoxic and DNA Intercalating Agents
Zhiyong CHEN,a Rihui CAO,a Buxi SHI,a Wei YI,a,c Liang YU,a Huacan SONG,*,a and Zhenhua REN*,b
b
a School of Chemistry and Chemical Engineering, Sun Yat-sen University; State Key Laboratory of Biocontrol, School of
c
Life Science, Sun Yat-sen University; 135 Xin Gang West Road, Guangzhou 510275, P. R. China: and Departement de
Pharmacochimie Moleculaire, UMR-CNRS 5063, Faculte de Pharmacie de Grenoble; 5 Avenue de Verdun, BP 138,
Meylan 38243, France. Received January 31, 2010; accepted March 24, 2010; published online April 14, 2010
A series of novel water-soluble b-carbolines bearing a flexible amino side chain was designed, synthesized
and evaluated as potent cytotoxic and DNA intercatalating agents. The N9-arylated alkyl substituted b-carbolines
represented the most interesting cytotoxic activities. The results suggested that (1) the N9-arylated alkyl sub-
stituents of b-carboline nucleus played a very important role in the modulation of the cytotoxic potencies; (2) the
length of the alkylamino side chain significantly affected their cytotoxic potency, and N,N-dimethylaminopropyl-
amino substituent were more favorable. In addition, these compounds were found to exhibit significant DNA in-
tercalating potencies.
Key words b-carboline; synthesis; cytotoxic; intercalating; melting temperature
b-Carboline alkaloids represent a large number of natu-
rally and synthetic indole alkaloids associated with a broad
spectrum of biochemical effects and pharmaceutical proper-
ties.1) Previous investigations focused on the effects of b-car-
boline alkoloids on the central nervous system (CNS).2—9)
Recent reports10—17) have pointed out b-carbolines as a class
of potential antitumor agents, which was discovered to func-
tion their antitumor activity through multiple mechanisms,
such as intercalating into DNA,11,18) inhibiting topoisomerase
I and II,13) CDK,19—21) MAPKAP-K2,22) MK-2,23) PLK124)
and kinesin Eg5.25)
Chart 1. Synthesis of b-Carboline Derivatives
Recently, our group investigations26—31) on the synthesis of
a variety of b-carboline derivatives and the evaluation of 3a—d, 4a—d, 5a—d and 6a—d are outlined in Chart 1. 1-
their antitumor activities unraveled that b-carbolines had po- Methyl-b-carboline-3-carboxaldehydes 1—6 were prepared
tent antitumor activities and the activities were correlated to from the L-tryptophan via six steps including the
both the planarity of the molecule and the presence of the Pictet–Spengler condensation, esterification, aromatization,
ring substituents. Structure–activity relationships (SARs) N-alkylation or N-arylation, reduction and oxidation as previ-
analysis suggested that the introduction of appropriate sub- ously described.26—28) The reaction of compounds 1—6 with
stituents into position-2, 3 and 9 played a vital role in deter- the corresponding diamines to form schiff bases took place
mining their antitumor effects, and the n-butyl, benzyl or readily at room temperature in good yield. The crude schiff
phenylpropyl substituents at position-9 was suitable pharma- bases without further purification were directly reduced with
cophoric group giving rise to some potent antitumor agents.
In continuing search for novel and effective antitumor lines 1a, 2a—d, 3a—d, 4a—d, 5a—d and 6a—d (Table 1)
NaBH3CN in anhydrous methanol to give the target b-carbo-
agents, we designed and synthesized a series of water-soluble in 40—78% yield. The chemical structures of all the synthe-
1
b-carbolines bearing a flexible alkylamino side chain at posi- sized compounds were characterized by MS, IR, H-NMR,
tion-3 and a alkyl or arylated alkyl substituent at position-9, and 13C-NMR spectra.
respectively. The selective introduction of a methyl, n-butyl,
benzyl, 4-fluorobenzyl and phenylpropyl substituents into Results and Discussion
position-9 of b-carboline nucleus was based on the previous
Cytotoxic Activity in Vitro The cytotoxic potential of
SARs analysis results, and the design of the amino sub- all newly synthesized b-carbolines was evaluated in vitro
stituents was limited to diethylaminoethylamino, dimethyl- against a panel of human tumor cell lines according to proce-
aminopropylamino diethylaminopropylamino and diethyl- dures described in our previous reports.26) The tumor cell line
aminobutylamino group. The purpose of this study was to in- panel consisted of renal carcinoma (769-P), epidermoid car-
vestigate effect of the flexible amino side chain moiety on the cinoma of the nasopharynx (KB), gastric carcinoma (BGC-
antitumor activity, with the ultimate aim of developing novel 823), renal carcinoma (786-0 and OS-RC-2), liver carcinoma
antitumor b-carbolines with improved water solubility and (HepG2), melanoma (A375), colon carcinoma (HT-29),
bioavailability.
prostate carcinoma (22RV1) and breast carcinoma (MCF-7).
The results were summarized in Table 1.
Chemistry
As shown in Table 1, compound 1a without substituent at
The synthetic routes of novel b-carbolines 1a, 2a—d, position-9 and compounds 2a—d bearing a methyl group at
∗ To whom correspondence should be addressed. e-mail: yjhxhc@mail.sysu.edu.cn; Renzhh@mail.sysu.edu.cn © 2010 Pharmaceutical Society of Japan

902
Vol. 58, No. 7
Table 1. Cytotoxicity of b-Carboline Derivatives in Vitroc) (IC50,a) mM)
Compound
R9
m
n
769-P
KB
BGC-823 786-0
HepG2
A375
HT-29 OS-RC-2 22RV1 MCF-7
1a
2a
2b
2c
2d
3a
3b
3c
3d
4a
4b
4c
4d
5a
5b
5c
5d
6a
6b
6c
6d
H
CH3
CH3
CH3
CH3
n-C4H9
n-C4H9
n-C4H9
1
0
1
1
2
0
1
1
2
0
1
1
2
0
1
1
2
0
1
1
2
0
1
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
Ͼ50
24.6
38.6
Ͼ50
47.1
8.0
Ͼ50
11.0
38.3
11.3
Ͼ50
11.0
40.3
Ͼ50
7.9
28.2
7.6
Ͼ50
36.1
27.8
4.0
Ͼ50
Ͼ50
25.4
Ͼ50
Ͼ50
18.0
16.0
17.4
13.4
29.5
5.1
10.0
13.3
17.3
5.0
5.3
8.6
Ͼ50
Ͼ50
Ͼ50
Ͼ50
Ͼ50
21.1
6.2
25.4
Ͼ50
48.9
Ͼ50
Ͼ50
7.7
13.5
22.1
4.2
34.1
6.2
12.7
13.3
12.8
3.2
12.0
3.2
10.0
5.5
12.8
13.0
16.0
Ͻ0.08
Ͼ50
Ͼ50
Ͼ50
Ͼ50
42.6
41.9
20.7
25.9
13.6
28.9
17.1
11.4
19.3
26.0
14.1
14.3
9.9
Ͼ50
Ͼ50
24.4
Ͼ50
24.9
4.6
12.7
15.1
12.7
19.6
1.6
46.4
Ͼ50
Ͼ50
Ͼ50
Ͼ50
Ͼ50
14.4
17.6
Ͼ50
Ͼ50
14.1
21.9
32.8
38.7
14.1
33.3
39.3
11.4
11.3
25.4
21.7
3.4
Ͼ50
Ͼ50
Ͼ50
Ͼ50
Ͼ50
25.3
7.3
Ͼ50
Ͼ50
Ͼ50
Ͼ50
Ͼ50
Ͼ50
36.6
Ͼ50
12.6
40.8
25.7
24.0
31.7
19.5
30.5
11.1
13.6
12.7
33.7
8.8
5.7
5.3
7.2
4.3
7.6
9.1
n-C4H9
14.4
19.8
1.6
18.1
23.2
26.5
1.5
15.8
12.1
8.7
3.6
6.4
25.7
19.2
7.1
CH2C6H5
CH2C6H5
CH2C6H5
CH2C6H5
CH2C6H4(p-F)
CH2C6H4(p-F)
CH2C6H4(p-F)
CH2C6H4(p-F)
(CH2)3C6H5
(CH2)3C6H5
(CH2)3C6H5
(CH2)3C6H5
Cisplatin
Paclitaxel
48.1
5.8
17.8
18.8
14.3
5.6
2.9
3.8
13.9
7.1
5.0
Ͼ50
4.6
30.8
32.7
5.3
5.4
5.2
6.8
8.1
4.8
3.2
8.9
4.6
8.1
9.0
18.9
2.0
10.9
11.6
27.1
4.2
32.2
7.8
30.1
10.9
25.6
12.3
4.6
7.9
3.8
5.7
20.4
13.4
1.5
15.1
11.9
22.5
13.3
9.4
9.5
11.4
4.9
Ͻ0.08
15.8
Ͼ50
0.38
11.4
12.4
1.3
0.08
0.81
Ͻ0.08
0.08
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
assay. b) Cell lines include renal carcinoma (769-P), epidermoid carcinoma of the nasopharynx (KB), gastric carcinoma (BGC-823), renal carcinoma (786-0 and OS-RC-2), liver
carcinoma (HepG2), melanoma (A375), colon carcinoma (HT-29), prostate carcinoma (22RV1) and breast carcinoma (MCF-7). c) The data represent the mean values of three in-
dependent determinations.
position-9 of b-carboline nucleus were almost inactive to all the binding of the drugs to CT-DNA results in considerable
human tumor cell lines at the concentration of 50 mM. As pre- spectral changes, characterized by a slight bathochromic shift
dicted, introducing an n-butyl, benzyl, 4-fluorobenzyl or and a marked hypochromic effect. Bathochromic shifts and
phenylpropyl substituent into position-9 of b-carboline core hypochromic effects are considered to be evidence of interac-
led to compounds 3a—d, 4a—d, 5a—d and 6a—d respec- tion of small molecules with DNA. Therefore, these results
tively, which all showed significant cytotoxic activity against indicated that this class of b-carboline derivatives had a sig-
most of human tumor cell lines with IC50 values lower than nificant interaction with CT-DNA double helix.
20 mM. Interestingly, the N9-arylated alkyl substituted b-
DNA Thermal Denaturation Studies Intercalation of
carbolines 4a—d, 5a—d and 6a—d displayed the most inter- small molecules into DNA double helix is known to increase
esting cytotoxic activities, and compounds 4b, 5b and 6b the DNA helix melting temperature.11,32,33) In order to con-
bearing a dimethylaminopropylamino group were found to firm the DNA intercalating ability of those compounds, we
be the most potent compounds with IC50 values lower than investigated the stabilization of the DNA helix by the se-
20 mM against nine human tumor cell lines. These results lected b-carbolines 1a, 2b, 3b, 4b and 6b using melting tem-
indicated that (1) the N9-arylated alkyl substituents of b-car- perature (Tm) studies to evaluate relative affinity for DNA of
boline nucleus played an important role in the modulation of the selected compounds. The Tm of CT-DNA in the presence
the cytotoxic potencies; (2) the length of the alkylamino side and absence of compounds 1a, 2b, 3b, 4b and 6b were
chain significantly affected their cytotoxic potency, and N,N- obtained from melting curves (not shown) and the results of
dimethylaminopropylamino substituent were more favorable. Tm analysis performed with CT-DNA are shown in Fig. 2.
UV Spectral Absorbance In order to elucidate the CT-DNA which melt at a low temperature (53.5 °C in
DNA-binding ability of this series of b-carboline derivatives, PE buffer) affords a sensitive determination of the DNA
the modification of the UV absorption spectra of the selected binding capacity of the studied molecules. As indicated in
compounds 1a, 2b, 3b, 4b and 6b in the absence and pres- Fig. 2, compound 1a without substituent at position-9 stabi-
ence of increasing concentrations of calf thymus DNA (CT- lized CT-DNA against heat denaturation with DTm value
DNA) was examined by UV spectroscopy based on the prin- (DTmϭTmdrug-DNA complexϪTmDNA alone) of 19.3 °C. 9-Methyl
ciple that the UV spectra of a substance changes if it inter- (compound 2b) and 9-n-butyl (compound 3b) substituted b-
acts with the DNA.11,32) Figure 1 illustrates the absorption carboline congeners markedly stabilized CT-DNA against
spectra of compounds 1a, 2b, 3b, 4b and 6b in the phosphate heat denaturation with DTm value of 24.4 and 21.4 °C, re-
ethylenediaminetetraacetic acid (PE) buffer (1 mM Na2HPO4, spectively. Whereas 9-benzyl (compound 4b) and 9-(3-
0.1 mM ethylenediaminetetraacetic acid (EDTA), pH 7.4) in phenyl)propyl (compound 6b) substituted b-carboline con-
the presence of increasing amounts of CT-DNA. In all cases, geners exhibited more weaker effect on CT-DNA thermal sta-

July 2010
903
Fig. 1. Absorption Spectra for Compounds 1a, 2b, 3b, 4b and 6b in 1 ml PE Buffer (1 mM Na2HPO4, 0.1 mM EDTA, pH 7.4 ) at Different Molarities of
CT-DNA
Top curve (0.0) and bottom curve (0.2 mM) were recorded in quartz cells (10 mm path length) by a UV–visible spectrophotometer at room temperature.
line nucleus facilitated the intercalating potency, and short
alkyl group was superior to arylated aklyl substituent. Unex-
pectedly, these data showed no obvious correlation between
their cytotoxic activities and DNA binding potencies.
Fluorescence Studies Fluorescence spectra measure-
ment is another useful technique to determine the binding
mode of small molecules with DNA helix.16,32) Compounds
1a, 2b, 3b, 4b and 6b present intrinsic fluorescence proper-
ties which could be used to evaluate their respective DNA-
binding potency. The effect of CT-DNA on the fluorescence
intensity of the selected b-carbolines 1a, 2b, 3b, 4b and 6b
was determined by the use of fluorescence spectroscopy.
Fig. 2. Variation of the DTm of the Complexs between the Tested Com-
pounds and CT-DNA
Melting temperature measurements were performed in PE buffer (1 mM Na2HPO4, From the titration of compounds 1a, 2b, 3b, 4b and 6b (Fig.
0.1 mM EDTA) at pH 7.4 with a drug/DNA ration of 0.2. Adr is abbreviation of adri-
3), the fluorescence intensity of all investigated compounds
amycin (doxorubicin hydrochloride).
gradually decreased with the increasing concentrations of
added CT-DNA. When the concentration of added CT-DNA
bility with DTm value of 15.6 and 18.0 °C, respectively. The was increased to 90 mM, the fluorescence intensity of all in-
results suggested that (1) these compounds could signifi- vestigated compounds was lowered to their minimum. In ad-
cantly stabilize the double helix of CT-DNA; (2) the intro- dition, over the course of the fluorescence quenching of all
duction of appropriate substituent into position-9 of b-carbo- investigated compounds, a slight bathochromic shift was also

904
Vol. 58, No. 7
Fig. 3. Fluorescence Spectra of the Various b-Carbolines Upon Incubation with Graded Concentration of CT-DNA
A fixed concentration of the various b-carbolines (10 mM) was incubated with increasing concentration of CT-DNA from 0 to 90 mM in PE buffer (1 mM Na2HPO4, 0.1 mM EDTA,
pH 7.4).
observed. These results indicated that such b-carbolines the significant spectral changes (bathochromic shifts and
could effectively interact with DNA.
hypochromic effects), elevating Tm value and fluorescence
quenching effects of these compounds in the presence of CT-
DNA were observed, suggesting that these compounds could
Conclusion
A series of water-soluble b-carbolines bearing a flexible significantly interact with DNA and remarkedly stabilizes the
amino side chain described in this paper were proved to be double helix of DNA. However, these data showed no obvi-
significantly cytotoxic activities. The N9-arylated alkyl sub- ous correlation between cytotoxic activity and DNA binding
stituented b-carbolines represented the most interesting cyto- capacity of the newly synthetic b-carbolines.
toxic activities. These results indicated that (1) the N9-ary-
In order to confirm the utility of the water-soluble b-car-
lated alkyl substituents of b-carboline nucleus played an bolines bearing a flexible amino side chain moiety as an
important role in the modulation of the cytotoxic potencies; interesting antitumor agent, compounds 4b, 5b and 6b are
(2) the length of the alkylamino side chain moiety also now selected and submitted to further acute toxicity and anti-
affected their cytotoxic potency, and N,N-dimethylamino- tumor activity studies in animal models, and the relative pos-
propylamino substituent were more favorable. In addition, sible results will be reported in due course.

July 2010
905
Experimental
20.7, 18.0, 8.3; ESI-MS m/z: 353.4 (Mϩ1)ϩ.
Reagents and General Procedures NMR spectra were recorded on a
3-[N-(2-Diethylamino)-ethyl]-aminomethyl-9-n-butyl-1-methyl-b-carbo-
Varian Mercury-Plus 300 spectrometers, Bruker AVANCE 400 and Varian line Hydrochloride Salt (3a): Yield 55%; IR (KBr, cmϪ1) n: 2969, 2619,
1
INOVA500NB in D2O or DMSO-d6 or D2OϩDMSO-d6 at 25 °C. All chemi-
1629, 1462, 1385, 1339, 1253, 1137, 1058, 1026, 755; H-NMR (500 MHz,
cal shifts (d) are quoted in parts per million downfield from tetramethylsi- D2O) d: 8.62 (s, 1H), 8.34 (d, Jϭ8.0 Hz, 1H), 7.88 (t, Jϭ7.5 Hz, 1H), 7.80
lane (TMS) and coupling constants (J) are given in Hz. Mass spectra were (d, Jϭ8.5 Hz, 1H), 7.52 (t, Jϭ7.5 Hz, 1H), 4.84 (s, 2H), 4.64 (t, Jϭ7.5 Hz,
obtained from VG ZAB-HS and LCMS-2010A. High-resolution mass spec-
2H), 3.74—3.77 (m, 2H), 3.65—3.68 (m, 2H), 3.37—3.42 (m, 4H), 3.27 (s,
trometry (HR-MS) was performed on MAT95XP. Infrared (IR) spectra were 3H), 1.82—1.88 (m, 2H), 1.43—1.46 (m, 2H), 1.40 (t, Jϭ7.5 Hz, 6H), 0.95
measured on VECTOR 22 spectrometer using a potassium bromide (KBr) (t, Jϭ7.5 Hz, 3H); 13C-NMR (100 MHz, D2O) d: 144.4, 139.8, 133.2, 133.0,
disk, scanning from 400 to 4000 cmϪ1. All reactions were monitored by TLC 132.1, 130.2, 122.6, 122.2, 119.0, 117.3, 111.1, 48.3, 47.8, 47.0, 44.9, 41.9,
(Merck Kieselgel GF254) and spots were visualized with UV light or iodine. 32.4, 19.4, 18.1, 13.0, 8.3; ESI-MS m/z: 367.4 (Mϩ1)ϩ.
All commercially available reagents and solvents were used without further
purification.
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-9-n-butyl-1-methyl-b-car-
boline Hydrochloride Salt (3b): Yield 42%; CH2Cl2/CH3OH/NH4OH,
General Procedures for the Synthesis of Substituted b-Carboline De- 95 : 5 : 1; IR (KBr, cmϪ1) n: 2957, 2727, 1625, 1536, 1466, 1382, 1340,
1
rivatives 1a, 2a—d, 3a—d, 4a—d, 5a—d and 6a—d A mixture of 1- 1252, 1133, 1058, 764; H-NMR (500 MHz, D2O) d: 8.57 (s, 1H), 8.24 (d,
methyl-b-carboline-3-carboxaldehyde (1 mmol), diamine (1.2 mmol), anhy- Jϭ8.5 Hz, 1H), 7.81 (t, Jϭ7.5 Hz, 1H), 7.70 (d, Jϭ8.5 Hz, 1H), 7.45 (t,
drous methanol (6 ml) and anhydrous CH2Cl2 (3 ml) was stirred at room Jϭ7.5 Hz, 1H), 4.84 (s, 2H), 4.53 (t, Jϭ7.5 Hz, 2H), 3.42—3.45 (m, 2H),
temperature overnight. The solvent was evaporated under vacuum to give the 3.35—3.38 (m, 2H), 3.22 (s, 3H), 2.99 (s, 6H), 2.30—2.37 (m, 2H), 1.75—
crude schiff base, which was used directly in the next step without further 1.81 (m, 2H), 1.37—1.41 (m, 2H), 0.93 (t, Jϭ7.5 Hz, 3H); 13C-NMR
purification.
(100 MHz, D2O) d: 144.1, 139.5, 132.9, 132.8, 132.1, 130.0, 122.5, 122.1,
NaBH3CN (10 mmol) was added to a solution of the crude schiff base in 118.7, 117.4, 110.9, 54.3, 47.2, 44.9 (2C), 43.0, 32.4, 21.3, 19.3, 18.0, 13.1;
anhydrous CH3OH (10 ml) at 0 °C. The mixture was stirred at room temper- ESI-MS m/z: 353.4 (Mϩ1)ϩ.
ature for 24 h and then concentrated under vacuum. The residue was dis-
solved in CH2Cl2 (50 ml) and washed with aqueous Na2CO3 (pH 10, 50 ml).
3-[N-(3-Diethylamino)-propyl]-aminomethyl-9-n-butyl-1-methyl-b-carbo-
line Hydrochloride Salt (3c): Yield 54%; CH2Cl2/CH3OH/NH4OH, 95 : 5 : 1;
The organic layer was separated, dried over anhydrous Na2SO4, filtered, and IR (KBr, cmϪ1) n: 2960, 2676, 1624, 1570, 1468, 1383, 1340, 1254, 1207,
concentrated under vacuum. The residue was purified by flash chromatogra- 1136, 1033, 755; 1H-NMR (500 MHz, D2O) d: 8.63 (s, 1H), 8.36 (d,
phy on silica gel (CH2Cl2/CH3OH/NH4OH, 95 : 5 : 1) to gain yellow oil. The Jϭ8.0 Hz, 1H), 7.89 (t, Jϭ7.5 Hz, 1H), 7.81 (d, Jϭ8.5 Hz, 1H), 7.53
oil was dissolved in 4 N HCl/ethanol (20 ml) and stirred at room temperature
(t, Jϭ7.0 Hz, 1H), 4.83 (s, 2H), 4.66 (t, Jϭ7.5 Hz, 2H), 3.43 (t, Jϭ7.5 Hz,
for 30 min, then removed the solvent under reduced pressure to obtain yel- 2H), 3.30—3.36 (m, 6H), 3.27 (s, 3H), 2.27—2.33 (m, 2H), 1.83—1.89 (m,
low solid.
2H), 1.39—1.47 (m, 2H), 1.36 (t, Jϭ7.0 Hz, 6H), 0.96 (t, Jϭ7.5 Hz, 3H);
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-1-methyl-b-carboline Hy- 13C-NMR (100 MHz, D2O) d: 144.2, 139.6, 132.9, 132.8, 132.1, 130.1,
drochloride Salt (1a): Yield 68%; IR (KBr, cmϪ1) n: 2937, 2745, 1630, 122.5, 122.1, 118.8, 117.4, 111.0, 48.5, 47.7, 47.3, 45.0, 44.9, 32.4, 20.9,
1473, 1384, 1343, 1241, 1050, 761; H-NMR (500 MHz, D2O) d: 8.22 (s,
1H), 7.90 (d, Jϭ8.0 Hz, 1H), 7.55—7.58 (m, 1H), 7.36 (d, Jϭ8.0 Hz, 1H),
1
19.4, 18.0, 13.1, 8.3; ESI-MS m/z: 381.4 (Mϩ1)ϩ.
3-[N-(4-Diethylamino)-butyl]-aminomethyl-9-n-butyl-1-methyl-b-carbo-
7.22 (t, Jϭ7.5 Hz, 1H), 4.62 (s, 2H), 3.29—3.32 (m, 2H), 3.24—3.28 (m, line Hydrochloride Salt (3d): Yield 60%; CH2Cl2/CH3OH/NH4OH, 95 : 5 : 1;
2H), 2.89 (s, 6H), 2.75 (s, 3H), 2.20—2.25 (m, 2H); 13C-NMR (100 MHz,
IR (KBr, cmϪ1) n: 2968, 2777, 1669, 1628, 1546, 1452, 1381, 1341, 1143,
1
D2Oϩdioxane) d: 142.8, 139.6, 133.1, 131.9, 131.4, 129.8, 122.5, 121.9, 1038, 774; H-NMR (500 MHz, D2O) d: 8.47 (s, 1H), 8.03 (d, Jϭ8.0 Hz,
119.1, 117.3, 112.3, 54.2, 47.4, 44.7, 42.9, 21.3, 15.7; electrospray ioniza- 1H), 7.64 (t, Jϭ7.5 Hz, 1H), 7.47 (d, Jϭ8.5 Hz, 1H), 7.27 (t, Jϭ7.5 Hz, 1H),
tion (ESI)-MS m/z: 297.4 (Mϩ1)ϩ.
4.79 (s, 2H), 4.29 (t, Jϭ7.5 Hz, 2H), 3.39 (t, Jϭ7.0 Hz, 2H), 3.23—3.29 (m,
6H), 3.10 (s, 3H), 1.88—1.97 (m, 4H), 1.57—1.63 (m, 2H), 1.26—1.34 (m,
8H), 0.86 (t, Jϭ7.0 Hz, 3H); 13C-NMR (125 MHz, D2O) d: 144.5, 139.9,
133.2, 133.1, 132.4, 130.7, 122.9, 122.4, 119.1, 117.6, 111.2, 51.4, 47.9
(2C), 47.5, 45.2, 32.7, 23.3, 21.2, 19.7, 18.4, 13.4, 8.7; ESI-MS m/z: 395.4
3-[N-(2-Diethylamino)-ethyl]-aminomethyl-1,9-dimethyl-b-carboline Hy-
drochloride Salt (2a): Yield 70%; IR (KBr, cmϪ1) n: 2942, 2685, 1628,
1
1466, 1387, 1341, 1136, 1027, 770; H-NMR (500 MHz, D2O) d: 8.31 (s,
1H), 7.81 (d, Jϭ8.0 Hz, 1H), 7.46—7.49 (m, 1H), 7.21 (d, Jϭ8.0 Hz, 1H),
7.11 (t, Jϭ7.5 Hz, 1H), 4.76 (s, 2H), 3.71—3.74 (m, 5H), 3.61—3.64 (m, (Mϩ1)ϩ.
2H), 3.30—3.34 (m, 4H), 2.97 (s, 3H), 1.31 (t, Jϭ7.5 Hz, 6H); 13C-NMR
3-[N-(2-Diethylamino)-ethyl]-aminomethyl-9-benzyl-1-methyl-b-carbo-
(100 MHz, D2Oϩdioxane) d: 144.0, 140.0, 133.2, 131.9, 131.7, 129.9, line Hydrochloride Salt (4a): Yield 48%; IR (KBr, cmϪ1) n: 2739, 1627,
1
122.0, 121.8, 118.2, 117.1, 110.2, 48.2, 47.6, 46.8, 41.9, 31.9, 17.9, 8.2; 1462, 1388, 1344, 1261, 1203, 1135, 1025, 765; H-NMR (500 MHz, D2O)
ESI-MS m/z: 325.4 (Mϩ1)ϩ.
d: 8.66 (s, 1H), 8.15 (d, Jϭ8.0 Hz, 1H), 7.37 (t, Jϭ8.0 Hz, 1H), 7.19 (t,
Jϭ7.5 Hz, 1H), 7.13 (d, Jϭ8.5 Hz, 1H), 6.98—7.00 (m, 3H), 6.70—6.72 (m,
2H), 5.52 (s, 2H), 4.89 (s, 2H), 3.81—3.84 (m, 2H), 3.68—3.71 (m, 2H),
3.33—3.38 (m, 4H), 2.84 (s, 3H), 1.34 (t, Jϭ7.5 Hz, 6H); 13C-NMR
(125 MHz, D2O) d: 144.3, 139.8, 136.1, 133.3, 133.1, 132.1, 130.6, 128.8,
127.6, 125.1, 122.8, 122.3, 118.9, 117.5, 110.5, 48.1, 47.7, 47.4, 46.8, 41.8,
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-1,9-dimethyl-b-carboline
Hydrochloride Salt (2b): Yield 78%; IR (KBr, cmϪ1) n: 2954, 2733, 1628,
1
1470, 1384, 1344, 1252, 1057, 773; H-NMR (500 MHz, D2O) d: 8.29 (s,
1H), 7.82 (d, Jϭ8.0 Hz, 1H), 7.46—7.49 (m, 1H), 7.21 (d, Jϭ8.5 Hz, 1H),
7.12 (t, Jϭ7.5 Hz, 1H), 4.71 (s, 2H), 3.73 (s, 3H), 3.35 (t, Jϭ8.0 Hz, 2H),
3.27—3.30 (m, 2H), 2.97 (s, 3H), 2.91 (s, 6H), 2.23—2.30 (m, 2H); 13C- 17.6, 8.1; ESI-MS m/z: 401.4 (Mϩ1)ϩ.
NMR (100 MHz, D2Oϩdioxane) d: 144.0 139.9, 133.2, 131.9, 131.7, 129.9,
122.1, 121.8, 118.2, 117.1, 110.2, 54.2, 47.2, 44.8, 42.9, 31.9, 21.3, 18.0;
ESI-MS m/z: 311.4 (Mϩ1)ϩ.
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-9-benzyl-1-methyl-b-car-
boline Hydrochloride Salt (4b): Yield 44%; CH2Cl2/CH3OH/NH4OH,
95 : 5 : 1; IR (KBr, cmϪ1) n: 2952, 2693, 1623, 1538, 1465, 1340, 1260,
1
3-[N-(3-Diethylamino)-propyl]-aminomethyl-1,9-dimethyl-b-carboline 1209, 760; H-NMR (500 MHz, D2O) d: 8.57 (s, 1H), 8.20 (d, Jϭ8.0 Hz,
Hydrochloride Salt (2c): Yield 75%; IR (KBr, cmϪ1) n: 2951, 2741, 1630,
1469, 1386, 1344, 1254, 1136, 1045, 768; 1H-NMR (500 MHz, D2O) d: 8.36
(s, 1H), 7.94 (d, Jϭ8.0 Hz, 1H), 7.56—7.60 (m, 1H), 7.34 (d, Jϭ8.5 Hz,
1H), 7.22 (t, Jϭ7.5 Hz, 1H), 4.72 (s, 2H), 3.85 (s, 3H), 3.35 (t, Jϭ8.0 Hz,
1H), 7.52—7.55 (m, 1H), 7.29—7.34 (m, 2H), 7.12—7.13 (m, 3H), 6.79—
6.80 (m, 2H), 5.66 (s, 2H), 4.75 (s, 2H), 3.34—3.37 (m, 2H), 3.26—3.29 (m,
2H), 2.90 (s, 6H), 2.87 (s, 3H), 2.22—2.29 (m, 2H); 13C-NMR (100 MHz,
D2Oϩ1,4-dioxane) d: 144.7, 140.3, 136.6, 133.8, 133.5, 132.5, 131.1,
2H), 3.21—3.28 (m, 6H), 3.03 (s, 3H), 2.20—2.25 (m, 2H), 1.27 (t, 129.2, 128.1, 125.5, 123.1, 122.7, 119.4, 117.7, 111.0, 54.4, 48.0, 47.5,
Jϭ7.5 Hz, 6H); 13C-NMR (100 MHz, D2Oϩdioxane) d: 144.2, 140.1, 133.4, 44.9, 43.0, 21.5, 17.9; ESI-MS m/z: 387.4 (Mϩ1)ϩ.
132.1, 131.8, 129.9, 122.2, 121.9, 118.4, 117.2, 110.4, 48.4, 47.6, 47.3,
3-[N-(3-Diethylamino)-propyl]-aminomethyl-9-benzyl-1-methyl-b-carbo-
44.9, 32.0, 20.8, 18.0, 8.2; ESI-MS m/z: 339.4 (Mϩ1)ϩ.
line Hydrochloride Salt (4c): Yield 52%; IR (KBr, cmϪ1) n: 2949, 2764,
3-[N-(4-Diethylamino)-butyl]-aminomethyl-1,9-dimethyl-b-carboline Hy- 1627, 1463, 1384, 1346, 1135, 1045, 749; 1H-NMR (500 MHz, D2O) d: 8.70
drochloride Salt (2d): Yield 75%; IR (KBr, cmϪ1) n: 2952, 2139, 1629, (s, 1H), 8.37 (d, Jϭ8.0 Hz, 1H), 7.73 (t, Jϭ7.5 Hz, 1H), 7.54 (d, Jϭ8.5 Hz,
1
1469, 1386, 1027, 766; H-NMR (300 MHz, D2O) d: 8.29 (s, 1H), 7.92 (d, 1H), 7.48 (t, Jϭ7.5 Hz, 1H), 7.28—7.29 (m, 3H), 6.95—6.96 (m, 2H), 5.85
Jϭ7.8 Hz, 1H), 7.55 (t, Jϭ7.2 Hz, 1H), 7.32 (d, Jϭ8.7 Hz, 1H), 7.18 (t,
(s, 2H), 4.85 (s, 2H), 3.45 (t, Jϭ7.5 Hz, 2H), 3.29—3.36 (m, 6H), 3.01 (s,
Jϭ7.2 Hz, 1H), 4.61 (s, 2H), 3.84 (s, 3H), 3.21 (t, Jϭ6.3 Hz, 2H), 3.11— 3H), 2.28—2.35 (m, 2H), 1.35 (t, Jϭ7.5 Hz, 6H); 13C-NMR (125 MHz,
3.16 (m, 6H), 2.99 (s, 3H), 1.75—1.77 (m, 4H), 1.18 (t, Jϭ8.0 Hz, 7.2H);
D2O) d: 145.2, 140.6, 137.0, 134.2, 133.9, 132.8, 131.4, 129.5, 128.3, 125.7,
13C-NMR (100 MHz, D2Oϩdioxane) d: 144.0, 139.9, 133.2, 131.9, 131.7, 123.4, 123.0, 119.7, 117.9, 111.3, 48.8, 48.3, 48.0, 47.8, 45.3, 21.2, 18.2,
130.2, 122.1, 121.8, 118.2, 117.1, 110.2, 50.9, 47.4 (2C), 47.1, 31.9, 22.8,
8.6; ESI-MS m/z: 415.4 (Mϩ1)ϩ.

906
Vol. 58, No. 7
2943, 2730, 1623, 1536, 1498, 1470, 1385, 1340, 1304, 1057, 758; 1H-NMR
(500 MHz, D2O) d: 8.39 (s, 1H), 8.12 (d, Jϭ8.0 Hz, 1H), 7.66—7.69 (m,
1H), 7.40 (d, Jϭ8.5 Hz, 1H), 7.35 (t, Jϭ7.0 Hz, 1H), 7.12—7.19 (m, 3H),
7.02 (t, Jϭ7.0 Hz, 2H), 4.69 (s, 2H), 4.33 (t, Jϭ7.5 Hz, 2H), 3.32 (t,
Jϭ7.5 Hz, 2H), 3.21—3.27 (m, 6H), 2.86 (s, 3H), 2.61 (t, Jϭ7.0 Hz, 2H),
2.18—2.24 (m, 2H), 1.98—2.04 (m, 2H), 1.26 (t, Jϭ7.0 Hz, 6H); 13C-NMR
(100 MHz, D2O) d: 143.9, 140.6, 139.4, 132.9, 132.8, 132.0, 130.4, 128.5,
128.2, 126.2, 122.7, 122.2, 119.0, 117.4, 110.6, 48.5, 47.7, 47.3, 45.0, 44.1,
31.8, 31.2, 20.8, 17.8, 8.3; ESI-MS m/z: 443.4 (Mϩ1)ϩ.
3-[N-(4-Diethylamino)-butyl]-aminomethyl-9-(3-phenyl)propyl-1-methyl-
b-carboline Hydrochloride Salt (6d): Yield 62%; IR (KBr, cmϪ1) n: 2945,
2733, 1626, 1464, 1387, 1345, 1033, 761; 1H-NMR (500 MHz, D2O) d: 8.46
(s, 1H), 8.17 (d, Jϭ8.0 Hz, 1H), 7.73 (t, Jϭ7.5 Hz, 1H), 7.39—7.45 (m, 2H),
7.19—7.24 (m, 3H), 7.05—7.07 (d, Jϭ7.0 Hz, 2H), 4.75 (s, 2H), 4.37 (t,
Jϭ7.0 Hz, 2H), 3.36 (t, Jϭ7.0 Hz, 2H), 3.22—3.29 (m, 6H), 2.92 (s, 3H),
2.66 (t, Jϭ6.5 Hz, 2H), 2.02—2.08 (m, 2H), 1.89—1.93 (m, 4H), 1.33 (t,
Jϭ7.5 Hz, 6H); 13C-NMR (300 MHz, DMSO-d6) d: 144.4, 141.5, 139.9,
133.8, 133.6, 132.4, 132.2, 129.0 (2C), 126.7, 123.3, 122.5, 119.8, 118.2,
112.1, 50.5, 46.7 (3C), 44.9, 32.8, 23.6, 21.1, 18.4, 9.3; ESI-MS m/z: 457.5
(Mϩ1)ϩ.
3-[N-(4-Diethylamino)-butyl]-aminomethyl-9-benzyl-1-methyl-b-carbo-
line Hydrochloride Salt (4d): Yield 40%; IR (KBr, cmϪ1) n: 2953, 2733,
1
1627, 1463, 1395, 1345, 1039, 764; H-NMR (500 MHz, D2O) d: 8.67 (s,
1H), 8.30 (d, Jϭ8.0 Hz, 1H), 7.61 (t, Jϭ7.0 Hz, 1H), 7.37—7.41 (m, 2H),
7.19—7.20 (m, 3H), 6.87—6.89 (m, 2H), 5.73 (s, 2H), 4.82 (s, 2H), 3.40 (t,
Jϭ7.0 Hz, 2H), 3.23—3.29 (m, 6H), 2.96 (s, 3H), 1.87—1.98 (m, 2H), 1.32
(t, Jϭ7.0 Hz, 6H); 13C-NMR (100 MHz, D2Oϩdioxane) d: 144.6, 140.0,
136.5, 133.6, 133.4, 132.4, 131.2, 129.1, 127.9, 125.4, 123.0, 122.6, 119.2,
117.6, 110.8, 50.9, 47.9, 47.4 (2C), 47.2, 22.9, 20.8, 17.8, 8.3; ESI-MS m/z:
429.4 (Mϩ1)ϩ.
3-[N-(2-Diethylamino)-ethyl]-aminomethyl-9-(4-fluoro)benzyl-1-methyl-
b-carboline Hydrochloride Salt (5a): Yield 52%; IR (KBr, cmϪ1) n: 2763,
1
2615, 1621, 1505, 1468, 1387, 1255, 1217, 1052, 758; H-NMR (400 MHz,
D2O) d: 8.62 (s, 1H), 8.17 (d, Jϭ8.0 Hz, 1H), 7.53 (t, Jϭ7.2 Hz, 1H), 7.27—
7.32 (m, 2H), 6.74—6.82 (m, 4H), 5.62 (s, 2H), 4.84 (s, 2H), 3.73—3.77 (m,
2H), 3.61—3.65 (m, 2H), 3.27—3.35 (m, 4H), 2.88 (s, 3H), 1.31 (t,
Jϭ7.2 Hz, 1H); 13C-NMR (100 MHz, D2O) d: 163.1, 160.7, 144.5, 140.2,
133.6, 133.5, 132.5, 132.3, 131.0, 127.3, 127.2, 123.0, 122.7, 119.3, 117.7,
115.8, 115.6, 110.8, 48.3, 47.8, 47.4, 46.9, 41.9, 17.8, 8.3; ESI-MS m/z:
419.4 (Mϩ1)ϩ.
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-9-(4-fluoro)benzyl-1-
methyl-b-carboline Hydrochloride Salt (5b): Yield 45%; IR (KBr, cmϪ1) n:
2956, 2652, 1626, 1507, 1466, 1384, 1338, 1220, 1157, 1056, 752; 1H-NMR
(500 MHz, D2O) d: 8.62 (s, 1H), 8.30 (d, Jϭ10.0 Hz, 1H), 7.67—7.71 (m,
1H), 7.49 (d, Jϭ10.5 Hz, 1H), 7.42 (t, Jϭ9 Hz, 1H), 6.87—6.96 (m, 4H),
5.78 (s, 2H), 4.78 (s, 2H ), 3.37 (t, Jϭ9.5 Hz, 2H), 3.27—3.31 (m, 2H), 2.96
(s, 3H), 2.92 (s, 6H), 2.23—2.31 (m, 2H); 13C-NMR (125 MHz, D2O) d:
163.2, 160.8, 144.8, 140.3, 133.9, 133.7, 132.5, 131.1, 127.3, 127.2, 123.1,
122.7, 119.5, 117.6, 115.9, 115.7, 111.0, 54.3, 47.5, 44.8, 42.9, 21.3, 17.9;
ESI-MS m/z: 405.4 (Mϩ1)ϩ.
3-[N-(3-Diethylamino)-propyl]-aminomethyl-9-(4-fluoro)benzyl-1-
methyl-b-carboline Hydrochloride Salt (5c): Yield 56%; IR (KBr, cmϪ1) n:
2943, 1624, 1546, 1509, 1471, 1383, 1222, 1160, 1056, 758; 1H-NMR
(400 MHz, D2O) d: 8.60 (s, 1H), 8.22 (d, Jϭ8.0 Hz, 1H), 7.58 (t, Jϭ7.2 Hz,
1H), 7.31—7.38 (m, 2H), 6.80—6.87 (m, 4H), 5.66 (s, 2H), 4.78 (s, 2H),
3.38 (t, Jϭ8.0 Hz, 2H), 3.21—3.30 (m, 6H), 2.90 (s, 3H), 2.21—2.29 (m,
2H), 1.27 (t, Jϭ6.8 Hz, 6H); 13C-NMR (100 MHz, D2O) d: 163.1, 160.7,
144.6, 140.2, 133.7, 133.5, 132.4, 131.2, 127.3, 127.2, 123.0, 122.7, 119.4,
117.7, 115.9, 115.7, 110.9, 48.5, 47.7, 47.5, 47.4, 45.0, 20.9, 17.9, 8.3; ESI-
MS m/z: 433.4 (Mϩ1)ϩ.
3-[N-(4-Diethylamino)-butyl]-aminomethyl-9-(4-fluoro)benzyl-1-methyl-
b-carboline Hydrochloride Salt (5d): Yield 50%; IR (KBr, cmϪ1) n: 2951,
2772, 1626, 1505, 1465, 1385, 1344, 1220, 1153, 1045, 761; 1H-NMR
(500 MHz, D2O) d: 8.65 (s, 1H), 8.12 (d, Jϭ8.0 Hz, 1H), 7.36 (t, Jϭ7.5 Hz,
1H), 7.12—7.16 (m, 2H), 6.69—6.72 (m, 2H), 6.63 (t, Jϭ8.5 Hz, 2H), 5.49
(s, 2H), 4.82 (s, 2H), 3.40 (t, Jϭ7.0 Hz, 2H), 3.19—3.24 (m, 6H), 2.86 (s,
3H), 1.87—1.95 (m, 4H), 1.27 (t, Jϭ7.0 Hz, 6H); 13C-NMR (100 MHz,
D2Oϩdioxane) d: 162.9, 160.5, 144.2, 139.8, 133.4, 132.3 (2C), 131.6,
127.4, 127.3, 123.1, 122.6, 119.2, 117.8, 115.8, 115.6, 110.6, 51.1, 47.6,
47.5, 47.4, 47.2, 23.1, 21.0, 17.9, 8.5; ESI-MS m/z: 447.4 (Mϩ1)ϩ.
3-[N-(2-Diethylamino)-ethyl]-aminomethyl-9-(3-phenyl)propyl-1-methyl-
b-carboline Hydrochloride Salt (6a): Yield 64%; IR (KBr, cmϪ1) n: 2931,
2669, 1621, 1494, 1435, 1384, 1337, 1247, 1139, 1053, 1024, 777, 753; 1H-
NMR (500 MHz, D2O) d: 8.52 (s, 1H), 8.27 (d, Jϭ8.0 Hz, 1H), 7.83 (t,
Jϭ7.5 Hz, 1H), 7.59 (d, Jϭ8.5 Hz, 1H), 7.49 (t, Jϭ7.0 Hz, 1H), 7.21—7.27
(m, 3H), 7.11 (d, Jϭ8.5 Hz, 2H), 4.79 (s, 2H), 4.54 (t, Jϭ7.0 Hz, 2H),
3.70—3.74 (m, 2H), 3.64—3.68 (m, 2H), 3.37—3.42 (m, 4H), 3.02 (s, 3H),
2.73 (t, Jϭ6.5 Hz, 2H), 2.15—2.21 (m, 2H), 1.40 (t, Jϭ7.5 Hz, 6H); 13C-
NMR (100 MHz, D2O) d: 143.7, 140.5, 139.3, 132.8, 132.7, 132.0, 130.3,
128.4, 128.2, 126.2, 122.6, 122.2, 118.9, 117.3, 110.4, 48.3, 47.6, 46.9,
44.0, 42.0, 31.8, 31.2, 17.7, 8.3; ESI-MS m/z: 429.4 (Mϩ1)ϩ.
Cytotoxicity Assays in Vitro Cytotoxicity assays in vitro were carried
out using 96 microtitre plate cultures and 3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide (MTT) staining according to the procedures
described in our previous report.22) Briefly, cells were grown in RPMI-1640
medium containing 10% (v/v) fetal calf serum and 100 U/ml penicillin and
100 U/ml streptomycin. Cultures were propagated at 37 °C in a humified
atmosphere containing 5% CO2. Cell lines were obtained from Shanghai
Cell Institute, Chinese Academy of Science. Drug stock solutions were pre-
pared in pure water. The human tumor cell line panel consisted of renal car-
cinoma (769-P), epidermoid carcinoma of the nasopharynx (KB), gastric
carcinoma (BGC-823), renal carcinoma (786-0 and OS-RC-2), liver carci-
noma (HepG2), melanoma (A375), colon carcinoma (HT-29), prostate carci-
noma (22RV1) and breast carcinoma (MCF-7). In all of these experiments,
three replicate wells were used to determine each point.
DNA Binding Studies The interaction of the selected b-carboline deriv-
atives with CT-DNA was studied by UV spectrometry following the methods
described by Xiao et al.11) with some modification. Measurements were
taken in PE buffer (1 mM Na2HPO4, 0.1 mM EDTA, pH 7.4) in a 1 cm path-
length quartz cuvette at room temperature using a Shimadzu UV 2501PC
Spectrometer. The cuvette initially held 0.75 ml of a 20 mM solution of com-
pounds 1a, 2b, 3b, 4b and 6b, respectively, and then was progressively
titrated by increasing amounts of CT-DNA to obtain the spectrum of fully
bound drugs in the presence of a large excess of DNA by means of a dis-
penser equipped with a 25 ml syringe and adequate Teflon tubing.
Determination of DTm Tm measurements were performed using a Shi-
madzu UV 2501PC Spectrometer and following the methods described by
Xiao et al.11) with slight modification. Experiments were carried out in PE
buffer (1 mM Na2HPO4, 0.1 mM EDTA, pH 7.4) in a thermostatically con-
trolled cell hold, and the quartz cuvette (1 cm path length) was heated by cir-
culating water at a heating rate of 0.5 °C/min from 25 to 95 °C. Doxorubicin
Hydrochloride was used as standards. In all cases, the ratio of compound to
CT-DNA is 0.2.
Fluorescence Spectroscopy Fluorescence spectral measurement16,32)
was recorded using 10 mM of the fluorescent drugs incubated in 1 ml of PE
buffer in the presence or absence of increasing concentrations of CT-DNA
(0, 10, 20, 30, 40, 50, 60, 70, 80, 90 mM) in a quartz cuvette of 10 mm path
length. The corresponding changes in the fluorescence intensity of the se-
lected compounds were observed on a Shimadzu RF-5310PC spectrofluo-
rometer at a fluorescence excitation wavelength of 372 nm.
Acknowledgements We are thankful for the financial support of this
3-[N-(3-Dimethylamino)-propyl]-aminomethyl-9-(3-phenyl)propyl-1-
work by Xinjiang Huashidan Pharmaceutical Co., Ltd.
methyl-b-carboline Hydrochloride Salt (6b): Yield 55%; IR (KBr, cmϪ1) n:
2936, 2711, 2407, 1632, 1508, 1454, 1381, 1336, 1056, 1026, 751; 1H-NMR References
(500 MHz, D2O) d: 8.68 (s, 1H), 8.31 (d, Jϭ8.0 Hz, 1H), 7.85 (t, Jϭ7.0 Hz,
1H), 7.55 (t, Jϭ7.5 Hz, 1H), 7.49 (d, Jϭ8.5 Hz, 1H), 7.35—7.41 (m, 3H),
7.20—7.22 (m, 2H), 5.01 (s, 2H), 4.44 (t, Jϭ7.5 Hz, 2H), 3.64 (t, Jϭ7.5 Hz,
2H), 3.54—3.59 (m, 2H), 3.20 (s, 6H), 3.10 (s, 3H), 2.78 (t, Jϭ7.5 Hz, 2H),
2.52—2.58 (m, 2H), 2.11—2.17 (m, 2H); 13C-NMR (75 MHz, D2O) d:
143.9, 140.6, 139.3, 132.8, 132.1, 130.4, 128.6, 128.4, 126.3, 122.9, 122.3,
119.0, 117.7, 110.5, 54.6, 47.4, 45.3, 44.3, 43.3, 32.1, 31.6, 21.7, 18.0; ESI-
MS m/z: 415.4 (Mϩ1)ϩ.
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3-[N-(3-Diethylamino)-propyl]-aminomethyl-9-(3-phenyl)propyl-1-
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July 2010
907
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