Synthesis and biological evaluation of novel alkyl diamine linked bivalent β-carbolines as angiogenesis inhibitors

Article abstract of DOI:10.1016/j.ejmech.2016.08.050

We have synthesized and evaluated a series of novel alkyl diamine linked bivalent β-carbolines as potent angiogenesis inhibitors. The results demonstrated that most bivalent β-carbolines exhibited significant antiproliferative effects against human umbilical vein cell lines EA.HY926. Compound 4m was found to be the most potent antiproliferative agent with IC₅₀value of 2.16?μM against EA.HY926?cell lines. Mechanism investigations revealed that compound 4m could significantly inhibit EA.HY926?cells migration and tube formation in a dose-dependent manner. Moreover, compound 4m also showed obvious angiogenesis inhibitory effects in CAM assay, and the antiangiogenetic potency was more potent than the reference drug Endostar. The bivalent β-carbolines might be served as candidates for the development of vascular targeting antitumor drugs.

Full text of DOI:10.1016/j.ejmech.2016.08.050

Accepted Manuscript
Synthesis and biological evaluation of novel alkyl diamine linked bivalent β-carbolines
as angiogenesis inhibitors
Wei Chen, Guoxian Zhang, Liang Guo, Wenxi Fan, Qin Ma, Xiaodong Zhang, Runlei
Du, Rihui Cao
PII:
S0223-5234(16)30703-6
10.1016/j.ejmech.2016.08.050
EJMECH 8846
DOI:
Reference:
To appear in: European Journal of Medicinal Chemistry
Received Date: 3 July 2016
Revised Date: 20 August 2016
Accepted Date: 22 August 2016
Please cite this article as: W. Chen, G. Zhang, L. Guo, W. Fan, Q. Ma, X. Zhang, R. Du, R. Cao,
Synthesis and biological evaluation of novel alkyl diamine linked bivalent β-carbolines as angiogenesis
inhibitors, European Journal of Medicinal Chemistry (2016), doi: 10.1016/j.ejmech.2016.08.050.
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ACCEPTED MANUSCRIPT
Graphic abstract

ACCEPTED MANUSCRIPT
Synthesis and biological evaluation of novel alkyl diamine
linked bivalent β-carbolines as angiogenesis inhibitors
c
a
c
c
c
b
Wei Chen , Guoxian Zhang , Liang Guo , Wenxi Fan , Qin Ma , Xiaodong Zhang ,
*
, b
, a
Runlei Du * , Rihui Cao
a
School of Chemistry and Chemical Engineering, Sun Yat-sen University,
135 Xin Gang West Road, Guangzhou 510275, P R China
b
College of Life Sciences, Wuhan University, 299 Ba Yi Road, Wuchang, 430072, P R China
c
Xinjiang Huashidan Pharmaceutical Co. Ltd., 45 He Nan East Road, Urumqi 830011,
P R China
Abstract
We have synthesized and evaluated a series of novel alkyl diamine linked bivalent
β-carbolines as potent angiogenesis inhibitors. The results demonstrated that most bivalent
β-carbolines exhibited significant antiproliferative effects against human umbilical vein cell lines
EA.HY926. Compound 4m was found to be the most potent antiproliferative agent with IC50 value
of 2.16 ꢀM against EA.HY926 cell lines. Mechanism investigations revealed that compound 4m
could significantly inhibit EA.HY926 cells migration and tube formation in a dose-dependent
manner. Moreover, compound 4m also showed obvious angiogenesis inhibitory effects in CAM
assay, and the antiangiogenetic potency was more potent than the reference drug Endostar. The
bivalent β-carbolines might be served as candidates for the development of vascular targeting
antitumor drugs.
Keywords: Synthesis; Bivalent β-carbolines; Antitumor; Angiogenesis inhibitors;
Structure-activity relationships.
*Corresponding authors Tel: 86-20-84110918 fax: 86-20-84112245, E-mail addressed:
runleidu@163.com (Runlei Du); caorihui@mail.sysu.edu.cn (Rihui Cao)
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1. Introduction
Angiogenesis, the sprouting of new blood capillaries from pre-existing vessels,
is a physiological process involving endothelial cells activation, invasion, migration,
proliferation, tube formation, and finally capillary network formation[1].
Angiogenesis is also vital for the sustained growth, proliferation, invasion and
metastasis of solid tumors [2]. Without the development and progression of new blood
vessels, tumors cannot deteriorate beyond a critical size or metastasize to other organs
[3]. Endothelial cells play an important role in the complicated process of tumor
angiogenesis. Therefore, inhibition of the proliferation, migration, and tube formation
of endothelial cells might be an effective therapy for suppressing tumor progression
and metastasis. Accordingly, the search for inhibitors of this process has become a hot
topic in the treatment of tumor, and several tumor angiogenesis drugs have been
marketed. Nowadays, there are still more than 80 angiogenesis inhibitors currently in
clinical trials [4].
The β-carbolines represent a large group of naturally occurring and synthetic
alkaloids associated with a broad spectrum of biochemical and pharmaceutical effects
[5]. In the last two decades, the β-carbolines have been characterized as a new class of
potential antitumor agents, and a large number of synthetic β-carbolines acting as
antitumor agents were reported [6-13, 51]. Previous investigations indicated that this
class of compounds exerted their antitumor effects through multiple mechanisms of
action including intercalating into DNA [14-15], inhibiting Topo I and II
(topoisomerase I and II) [16-17], CDK (cyclin-dependent kinase) [18-19], MK-2
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(mitogen activated protein kinase-activated protein kinase 2) [20], kinesin-like protein
Eg5 [21] and IKK (I-Kappa-B kinase) [22].
In our previous reports, we described the preparation and antitumor activities in
vitro [23-36] and in vivo [23, 25, 35-36] of numerous β-carboline derivatives bearing
various substituents in position-1, 2, 3, 7 and 9 of β-carboline nucleus. The SARs
analysis indicated that (1) the common β-carboline moiety was very important for
their potential antitumor activities; (2) the introduction of appropriate substituents into
position-1, 3 and 9 of β-carboline nucleus faciliated their antitumor potencies. Our
previous studies on the mechanism of action demonstrated that the ability of
β-carbolines to act as DNA intercalating agents and Top I inhibitors was related to
their potent antitumor activities [37], and these molecules could pass through cell
membrane and penetrate into cell nucleus quickly resulting in intercalating into DNA
in cells [26]. In addition, some β-carbolines were observed to induce apoptosis in
HepG2 cells and down-regulate the expression of Bcl-2 gene and upregulate the
expression of death receptor Fas without altering the level of Bax and p53 [38]. Our
recent investigations revealed that N2-benzyl substituted quaternary β-carbolines was
new and potent PLK inhibitors with potential for cancer treatment [39-40].
Previous reports [41-45] demonstrated that dimerization of various antitumor
agents by an appropriate linker could lead to significantly improved antitumor
activities (100 to 500-fold better than the corresponding monomers). Consequently,
dimers of β-carboline were also expected to show more significant in vitro antitumor
activity and more potent in vivo efficacy than monomers. Firstly, our group reported
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the synthesis, in vitro evaluation, in vivo efficacies and structure-activity relationships
for the new bivalent β-carbolines linked at the N-9 and C-3 position with a spacer of
three to ten methylene units, respectively (Figure 1) [46-47], however, these bivalent
β-carbolines had limited utility for cancer therapy because of their poor water
solubility. To circumvent the water solubility problem and find congeners more active
as potential antitumor agents, recently, we described the synthesis and cytotoxic
potencies of novel bivalent β-carbolines linked with piperazine group (Figure 1), and
these compounds exhibited significantly improved antitumor activities and water
solubility [48]. The bivalent β-carbolines was originally expected to exerted their
antitumor effects by DNA intercalating or Top I inhibiting effect. Unfortunately, our
group found that these compounds had no effect on DNA and Top I, but exhibitd
significant inhibitory effect on the vessel growth in chicken chorioallantoic membrane
(CAM) assay [48]. These molecules might be served as angiogenesis inhibitors for the
development of vascular targeting antitumor drugs.
In a continuing effort to develop novel bivalent β-carbolines endowed with
better antiangiogenic activity, in the present investigation, we designed and
synthesized a series of novel alkyl diamine linked bivalent β-carbolines as potent
antivascular agents. These compounds were expected to exhibit significantly
improved antivascular activity due to the improved water solubility. We report herein
the preparation of novel bivalent β-carbolines and their biological evaluation as
angiogenesis inhibitors.
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2. Chemistry
The synthetic route for the preparation of monovalent and bivalent β-carbolines
is shown in Scheme 1. The monovalent β-carboline 1 was obtained by the
condensation of L-tryptophan with acetaldehyde in acid solution and followed by
aromatization, oxidation and decarboxylation in a single step through the action of
potassium dichromate [49]. The N9 of monovalent β-carboline 1 was alkylated or
arylated by the action of sodium hydride in anhydrous DMF followed by the addition
of the appropriate alkylating and arylating agents to afford intermediates 2a–l [23] in
65-82% yield. The methyl group in position-1 of 2a–l was further oxidized to
carboxaldehyde
by
SeO2
in
anhydrous
dioxane
to
provide
β-carboline-1-carboxaldehydes 3a–l in 31-61% yield [34].
The reaction of compounds 3a-l with the corresponding sym-diamines to form
schiff bases took place readily at room temperature in good yield. The crude schiff
bases without further purification were directly reduced with NaBH3CN in anhydrous
methanol to give the target bivalent β-carbolines 4a-ad in 48-89% yield. The chemical
1
structures of all new bivalent β-carbolines were characterized by ESI-MS, H NMR,
13C NMR and HRMS.
3. Results and Discussion
3.1 Inhibitory effect on EA.HY926s proliferation
The inhibitory potencies of novel bivalent β-carbolines against human umbilical
vein cell lines EA.HY926 were investigated and compared with the reference drugs
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CA4P and Endostar. In order to enhance the solubility in aqueous solution, all bivalent
β-carbolines were prepared in the form of hydrochloride salt before use. As predicted,
the hydrochloride salt of novel bivalent β-carbolines linked with a spacer of alkyl
diamine in position-3 showed good water-solubility (more than 10 mg/ml). The
results were summarized in Table 1.
As shown in Table 1, most bivalent β-carbolines exhibited good antiproliferative
effects with IC50 value of lower than 10.0ꢀM against human umbilical vein cell lines
EA.HY926. Compounds 4l, 4m, 4n, 4v, 4x, 4z, 4ab, 4ac and 4ad displayed
significant antiproliferative potencies with IC50 value of lower than 5.0ꢀM
against EA.HY926 cell lines, and compound 4m was found to be the most potent
antiproliferative agent with IC50 value of 2.16ꢀM against EA.HY926 cell lines, and
the antiproliferative potency of compound 4m was comparable with positive control
drug Endostar (1.76 ꢀM).
We examined the influence of the substituents in position-9 of β-carboline ring
on antiproliferative effects. Compounds 4a and 4b having no substituent in position-9
of β-carboline nucleus showed weak antiproliferative effects with IC50 value of higher
than 10ꢀM against EA.HY926 cell lines. Similarly, compounds 4c and 4d bearing a
methyl group in position-9 of β-carboline nucleus also displayed weak
antiproliferative potencies against EA.HY926 cell lines. While compounds 4e-ad
bearing an ethyl (4e-f), isorpropyl (4g-h), isobutyl (4i-j), n-butyl (4k-n), n-hexyl
(4o-r), n-octyl (4s-t), benzyl (4u-v), 4-fluorobenzyl (4w-x), 3-chlorobenzyl (4y-z) and
3-phenylpropyl (4aa-ad) group in position-9 of β-carboline ring, respectively,
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exhibited good to potent antiproliferative potencies with IC50 value of lower than
10.0ꢀM against EA.HY926 cell lines.
Of all bivalent β-carbolines with a linker of five methylene units, compound 4b
with no subsitiuent in position-9 of β-carboline nucleus showed weak antiproliferative
effect against EA.HY926 cell lines. Interestingly, compounds bearing an n-butyl (4m),
n-hexyl (4q), n-octyl (4t), 3-chlorobenzyl (4z) and 3-phenylpropyl (4ac) group in
position-9 of β-carboline nucleus, respectively, exhibited good to strong
antiproliferative effects with the tendency of n-butyl > 3-phenylpropyl >
3-chlorobenzyl > n-hexyl > n-octyl. Similarly, the antiproliferative potencies of
compounds 4d, 4h, 4j, 4n, 4r, 4v and 4ad with a linker of six methylene units
followed the sequence of 4n (n-butyl) > 4ad (3-phenylpropyl) > 4v (benzyl) > 4f
(ethyl) > 4j (isobutyl) > 4r (n-hexyl) > 4h (isopropyl) > 4d (methyl), and the
antiproliferative potencies of compounds 4a, 4c, 4f, 4i, 4l, 4p, 4s, 4x and 4ab with a
linker of four methylene units followed the sequence of 4l (n-butyl) > 4ab
(3-phenylpropyl) > 4x (4-fluorobenzyl) > 4f (ethyl) > 4p (n-hexyl) > 4i (isobutyl) > 4s
(n-octyl) > 4c (methyl) > 4a (H). Exceptionally, compounds 4e, 4g, 4k, 4o, 4u, 4w, 4y
and 4aa with a linker of three methylene units showed no distinct difference and the
IC50 values of this class of compounds ranged from 7.77 to 9.39ꢀM. These data
suggested that the introduction substituent into position-9 of β-carboline ring might
facilitated their antiproliferative potencies, and the four to six methylene linear alkyl
and arylated alkyl subsitituents were the optimal group giving rise to potent
antiproliferative agents.
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We also examined the influence of the linker length of bivalent β-carbolines on
antiproliferative activities. Compounds 4b, 4t and 4z with a linker of five methylene
units exhibited more potent antiproliferative effects than the analogues 4a (n=4), 4s
(n=4) and 4y (n=3). Of all bivalent β-carbolines having an n-butyl group in position-9
of β-carboline nucleus, compounds 4m with a linker of five methylene units exhibited
more potent antiproliferative effects than the analogues 4k, 4l and 4n and followed
the tendency of 4m (n=5) > 4n (n=6) > 4l (n=4) > 4k (n=3). A similar tendency also
applied to compounds 4o-r and 4aa-ad bearing an n-hexyl and 3-phenylpropyl group
in position-9 of of β-carboline nucleus, respectively. These results showed clearly that
the length of the linker had a major effect on the bivalent β-carbolines to inhibit tumor
cell growth and five to six methylene units might be more favorable.
3.2 Inhibitory effect on EA.HY926s migration
Cell migration is an essential feature for vascular endothelial cells in angiogenesis.
Logically, we investigated the inhibitory effect on the EA.HY926s chemotactic
motility of the most potent compound 4m by wound-healing assay. As shown in
Figure 2, compound 4m could inhibit VEGF-induced EA.HY926s migration in a
dose-dependent manner ranging from 0.3ꢀM to 30ꢀM. Treatment with compound 4m
significantly inhibited EA.HY926s migration at concentration of 30ꢀM and the
inhibitory potency of compound 4m was more potent than positive drug Endostar.
3.3 Inhibitory effect on EA.HY926s tube formation
We also evaluated the ability of the selected compound 4m in a tube formation
assay. EA.HY926s plated on a Matrigel coated plate could formed capillary-like
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tubules with multicentric junctions in cell cultured in the absence of compound
(control). After 24 h treatment in different concentrantions (0.3-30ꢀM) of compound
4m, the capillary-like tubes were interrupted in different levels (Figure 3A).
Quantitative image analysis showed that compound 4m significantly decreased the
capillary-like tubules in a concentration-dependent manner (Figure 3B).
3.4 Anti-angiogenic activity in vivo
The most potent compound 4m was selected to evaluate the angiogenetic activity
by CAM assay. The inhibitory effects of compound 4m on angiogenesis of CAM are
shown in Figure 4A. The anti-angiogenetic activities of compounds 7g was
semiquantitatively analyzed using Graph Pad Prism 5.0 (shown in Figure 4B). The
result showed that compound 4m (p < 0.05) could inhibit the angiogenesis of CAM.
The anti-angiogenetic activity of compound 4m was more potent than Endostar in
vivo CAM assay at the same dose (30ꢀM).
4. Conclusion
A series of novel alkyl diamine linked bivalent β-carbolines with linkers of
various lengths and incorporating different substituents into position-9 was
synthesized and evaluated as angiogenesis inhibitors. Most bivalent β-carbolines
exhibited significant antiproliferative activities against human umbilical vein cell lines
EA.HY926. Preliminary structure-activity relationships information revealed that (1)
the introduction substituent into position-9 of β-carboline ring might facilitate their
antiproliferative potencies, and the four to six methylene linear alkyl and arylated
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alkyl subsitituents were the optimal group giving rise to potent antiproliferative agents.
(2) the length of the linker had a major effect on the bivalent β-carbolines to inhibit
tumor cell growth and five to six methylene units might be more favorable. The most
potent compound 4m was found to significantly inhibit EA.HY926s migration and
tube formation in a dose-dependent manner. Moreover, compound 4m showed
obvious angiogenesis inhibitory effects in CAM assay, and the anti-angiogenetic
potency was more potent than the reference drug Endostar. Further investigations to
confirm antitumor efficacy in animal models and elucidate the pharmacological
mechanisms of this class of compounds are underway in our laboratory, and the data
will be published elsewhere.
5. Experimental protocols
5. Experimental Section
5.1 Reagents and general methods
All reagents were purchased from commercial suppliers and were dried and
purified when necessary, and the preparation of monovalent β-carbolines 2a-c, 2f, 2i-l,
3a-c, 3f and 3i-l has been already described in our previous reports [25, 34].
Melting points were determined in capillary tubes on an electrothermal PIF
YRT-3 apparatus and without correction. MS spectra were obtained from VG
1
ZAB-HS spectrometer. H NMR and 13C NMR spectra were recorded on a
Mercury-Plus 300 spectrometer at 300 MHz and 75 MHz, respectively, using TMS as
internal standard and CDCl3 as solvent and chemical shifts (δ) were expressed in ppm.
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HRMS were obtained from ESI-Q-TOF maxis 4G spectrometer. Silica gel F254 were
used in analytical thin-layer chromatography (TLC) and silica gel were used in
column chromatography respectively.
5.2 General procedure for the preparation of 9-alkyl substituted β-carbolines 2d-e
and 2g-h.
A mixture of 1-methyl-β-carboline (3.64 g, 20 mmol) and anhydrous DMF (75
ml) was stirred at room temperature until clear, and then 60% NaH (1.2 g, 30 mmol)
and halogenated alkane (40 mmol) were added. The mixture was stirred at room
temperature. After completion of the reaction as indicated by TLC, the solution was
poured into H2O (100 mL) and extracted with ethyl acetate. The organic phase was
washed with water and brine, then dried over anhydrous sodium sulfate, filtered and
evaporated. The resulting oil was purified by silica column chromatography with
ethyl acetate as the eluent to successfully afford the desirable products.
5.2.1 9-Isopropyl-1-methyl-β-carboline (2d): White solid was obtained (2.91g, 65％).
1
Mp 135.3-138.1℃. ESI-MS m/z: 224.9 [M+H]+. H NMR (300MHz, CDCl3): δ 8.31
(d, J = 5.1 Hz, 1H, ArH); 8.12 (d, J = 7.8 Hz, 1H, ArH); 7.82 (d, J = 5.1 Hz, 1H, ArH);
7.70 (d, J = 8.4 Hz, 1H, ArH); 7.51 (t, J = 8.4 Hz, 1H, ArH); 7.29-7.22 (m, 1H, ArH);
5.62-5.50 (m, 1H, NCH[CH3]2); 3.06 (s, 3H, CH3); 1.76 (d, J = 7.2 Hz, 6H,
NCH[CH3]2). 13C NMR (75MHz, CDCl3): δ 141.2, 140.0, 137.8, 135.9, 129.1, 127.6,
122.8, 121.8, 119.5, 113.4, 113.0, 48.4, 25.2, 21.7.
5.2.2 9-Isobutyl-1-methyl-β-carboline (2e): White solid was obtained (3.76g, 79％).
Mp 71.8-72.6℃. ESI-MS m/z: 238.8 [M+H]+. 1H NMR (300MHz, CDCl3): δ 8.33 (d,
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J = 5.1 Hz, 1H, ArH); 8.11 (d, J = 7.8 Hz, 1H, ArH); 7.84 (d, J = 5.1 Hz, 1H, ArH);
7.55 (t, J = 8.4 Hz, 1H, ArH); 7.46 (d, J = 8.4 Hz, 1H, ArH); 7.28-7.23 (m, 1H, ArH);
4.36 (d, J = 7.5 Hz, 2H, NCH2CH[CH3]2); 3.04 (s, 3H, CH3); 2.35-2.20 (m, 1H,
13
NCH2CH[CH3]2 ); 0.94 (d, J = 6.6 Hz, 6H, NCH2CH[CH3]2). C NMR (75MHz,
CDCl3): δ 142.1, 141.5, 138.2, 135.5, 129.1, 128.0, 121.5, 119.6, 113.0, 110.6, 52.0,
31.0, 24.2, 20.5.
5.2.3 9-n-Hexyl-1-methyl-β-carboline (2g): White solid was obtained (4.36g, 82％).
Mp 49.2-52.3℃. ESI-MS m/z: 266.9 [M+H]+. 1H NMR (300MHz, CDCl3): δ 8.31 (d,
J = 5.1 Hz, 1H, ArH); 8.11 (d, J = 7.8 Hz, 1H, ArH); 7.83 (d, J = 5.1 Hz, 1H, ArH);
7.57 (t, J = 8.4 Hz, 1H, ArH); 7.45 (d, J = 8.4 Hz, 1H, ArH); 7.29-7.25 (m, 1H, ArH);
4.52 (t, J = 8.1 Hz, 2H, NCH2[CH2]4CH3); 3.06 (s, 3H, CH3); 1.91-1.77 (m, 2H,
NCH2CH2[CH2]3CH3); 1.50-1.23 (m, 6H, NCH2CH2[CH2]3CH3); 0.90 (t, J = 6.6 Hz,
3H, NCH2[CH2]4CH3). 13C NMR (75MHz, CDCl3): δ 141.4, 141.2, 137.9, 135.1,
129.0, 128.1, 121.5, 121.3, 119.6, 113.0, 109.7, 45.0, 31.8, 31.0, 26.9, 23.8, 22.9,
14.3.
5.2.4 9-n-Octyl-1-methyl-β-carboline (2h): Yellow oil was obtained (4.76g, 81％).
1
ESI-MS m/z: 294.8 [M+H]+. H NMR (300MHz, CDCl3): δ 8.31 (d, J = 5.1 Hz, 1H,
ArH); 8.10 (d, J = 7.8 Hz, 1H, ArH); 7.82 (d, J = 5.1 Hz, 1H, ArH); 7.57 (t, J = 8.4 Hz,
1H, ArH); 7.44 (d, J = 8.4 Hz, 1H, ArH); 7.29-7.22 (m, 1H, ArH); 4.50 (t, J = 7.8 Hz,
2H, NCH2[CH2]6CH3); 3.05 (s, 3H, CH3); 1.90-1.77 (m, 2H, NCH2CH2[CH2]5CH3);
1.48-1.23 (m, 10H, NCH2CH2[CH2]5CH3); 0.89 (t, J = 6.6 Hz, 3H, NCH2[CH2]6CH3).
13C NMR (75MHz, CDCl3): δ 141.6, 141.4, 138.1, 135.3, 129.2, 128.2, 121.6, 121.5,
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119.7, 113.1, 109.9, 45.2, 32.1, 31.1, 29.6, 29.5, 27.3, 23.9, 22.9, 14.4.
5.3. General procedures for the synthesis of 9-alkyl substituted β-carboline-1-
carboxaldehydes 3a-d and 3g-h.
To a solution of 2a-d and 2g-h (15 mmol) in dioxane (100 mL) was added SeO2
(40 mmol). The suspension was refluxed for 2 h. After completion of the reaction as
indicated by TLC, the mixture was cooled and filtered through Celite. The filtrate was
evaporated under reduced pressure. The residue was crystallized from acetone or
acetone-petroleum ether to afford the desirable products.
5.3.1 β-Carboline-1-carboxaldehyde (3a): Yellow solid was obtained (1.09g, 31％).
Mp 197.5-199.3℃. ESI-MS m/z: 294.8 [M+H]+. 1H NMR (300MHz, CDCl3): δ 10.35
(s, 1H, CHO); 10.06 (s, 1H, NH); 8.64 (d, J = 5.1 Hz, 1H, ArH); 8.20-8.14 (m, 2H,
13
ArH); 7.67-7.57 (m, 2H, ArH); 7.37 (t, J = 6.3 Hz, 1H, ArH). C NMR (75MHz,
CDCl3): δ 195.7, 141.4, 139.7, 136.1, 135.3, 131.7, 129.7, 122.0, 121.3, 120.6, 119.4,
112.2.
5.3.2 9-Methyl-β-carboline-1-carboxaldehyde (3b): Yellow solid was obtained (1.63g,
1
52％). Mp 130.4-132.4℃. ESI-MS m/z: 196.8 [M+H]+. H NMR (300MHz, CDCl3):
δ 10.31 (s, 1H, CHO); 8.62 (d, J = 4.8 Hz, 1H, ArH); 8.17-8.12 (m, 2H, ArH); 7.67 (t,
J = 8.4 Hz, 1H, ArH); 7.52 (d, J = 8.4 Hz, 1H, ArH); 4.24 (s, 3H, NCH3). 13C NMR
(75MHz, CDCl3): δ 193.6, 143.1, 138.3, 137.6, 135.9, 132.2, 129.4, 121.3, 120.8,
120.5, 118.5, 110.2, 34.6.
5.3.3 9-Ethyl-β-carboline-1-carboxaldehyde (3c): Yellow solid was obtained (1.71g,
1
51％). Mp 58.3-59.9℃. ESI-MS m/z: 224.9 [M+H]+. H NMR (300MHz, CDCl3): δ
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10.33 (s, 1H, CHO); 8.64 (d, J = 4.8 Hz, 1H, ArH); 8.20-8.14 (m, 2H, ArH); 7.67 (t, J
= 7.2 Hz, 1H, ArH); 7.56 (d, J = 8.1 Hz, 1H, ArH); 7.36 (t, J = 7.2 Hz, 1H, ArH);
4.98-4.88 (m, 2H, NCH2CH3); 1.43 (t, J = 6.9 Hz, 1H, NCH2CH3). 13C NMR (75MHz,
CDCl3): δ 193.9, 142.0, 138.2, 137.5, 134.8, 132.4, 129.4, 121.4, 120.8, 120.8, 118.6,
110.3, 41.9, 15.2.
5.3.4 9-Isopropyl-β-carboline-1-carboxaldehyde (3d): Yellow solid was obtained
1
(1.89g, 53％). Mp 43.3-46.7℃. ESI-MS m/z: 238.8 [M+H]+. H NMR (300MHz,
CDCl3): δ 10.31 (s, 1H, CHO); 8.62 (d, J = 4.8 Hz, 1H, ArH); 8.18-8.12 (m, 2H, ArH);
7.79 (t, J = 8.4 Hz, 1H, ArH); 7.60 (d, J = 7.2 Hz, 1H, ArH); 7.33 (t, J = 7.2 Hz, 1H,
13
ArH); 5.88-5.72 (m, 1H, NCH[CH3]2); 1.74 (d, J = 6.9 Hz, 6H, NCH[CH3]2). C
NMR (75MHz, CDCl3): δ 194.1, 140.9, 138.4, 137.8, 136.3, 132.3, 128.7, 122.6,
121.8, 120.6, 118.5, 114.1, 51.4, 21.4.
5.3.5 9-n-Hexyl-β-carboline-1-carboxaldehyde (3g):Yellow solid was obtained
1
(2.56g, 61％). Mp 39.1-42.5℃. ESI-MS m/z: 280.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 10.32 (s, 1H, CHO); 8.63 (d, J = 4.8 Hz, 1H, ArH); 8.20-8.13 (m, 2H, ArH);
7.66 (t, J = 8.4 Hz, 1H, ArH); 7.54 (d, J = 8.4 Hz, 1H, ArH); 7.35 (t, J = 7.5 Hz, 1H,
ArH); 4.86 (t, J = 7.5 Hz, 2H, NCH2[CH2]4CH3); 1.83-1.71 (m, 2H,
NCH2CH2[CH2]3CH3); 1.43-1.21 (m, 6H, NCH2CH2[CH2]3CH3); 0.87 (t, J = 6.6 Hz,
3H, NCH2[CH2]4CH3). 13C NMR (75MHz, CDCl3): δ 193.9, 142.5, 138.3, 137.8,
135.2, 132.6, 129.4, 121.5, 120.9, 120.8, 118.7, 110.7, 47.1, 31.8, 30.0, 26.7, 22.9,
14.3.
5.3.6 9-n-Octyl-β-carboline-1-carboxaldehyde (3h): Yellow solid was obtained
14

ACCEPTED MANUSCRIPT
1
(2.72g, 59％). Mp 45.5-47.4℃. ESI-MS m/z: 308.8 [M+H]+. H NMR (300MHz,
CDCl3): δ 10.32 (s, 1H, CHO); 8.64 (d, J = 5.1 Hz, 1H, ArH); 8.20-8.14 (m, 2H, ArH);
7.66 (t, J = 8.4 Hz, 1H, ArH); 7.54 (d, J = 8.4 Hz, 1H, ArH); 7.36 (t, J = 7.2 Hz, 1H,
ArH); 4.87 (t, J = 7.5 Hz, 2H, NCH2[CH2]6CH3); 1.83-1.71 (m, 2H,
NCH2CH2[CH2]5CH3); 1.43-1.21 (m, 10H, NCH2CH2[CH2]5CH3); 0.87 (t, J = 6.6 Hz,
3H, NCH2[CH2]6CH3). 13C NMR (75MHz, CDCl3): δ 193.9, 142.5, 138.3, 137.8,
135.2, 132.6, 129.4, 121.5, 120.9, 120.8, 118.7, 110.7, 47.1, 32.1, 30.0, 29.7, 29.5,
27.0, 23.0, 14.5.
5.4. General procedure for the preparation of bivalent β-carbolines 4a-ad.
A mixture of β-carboline-1-carboxaldehydes (2.2 mmol), anhydrous methanol
(30mL) and anhydrous CH2Cl2 (10 mL) was stirred at room temperature for 10 min,
and the corresponding sym-diamine (1.0 mmol) was added. The mixture was refluxed
for 2 h, and the solvent was evaporated under vacuum to give the crude Schiff base,
which was used directly in the next step without further purification.
NaBH3CN (5 mmol) was added to a solution of the above-mentioned crude
o
Schiff base in anhydrous CH3OH (30 mL) at 0 C. The mixture was stirred at room
temperature for 4-6 h. After completion of the reaction as indicated by TLC, the
reaction mixture was concentrated under vacuum. The residue was dissolved in
CH2Cl2 (150 mL) and washed with aqueous Na2CO3 (pH 10, 50 mL). The organic
layer was separated, dried over anhydrous Na2SO4, filtered, and concentrated under
vacuum. The residue was purified by flash chromatography on silica gel
(CH2Cl2/CH3OH/NH4OH, 100:1:0.8) to provide target products.
15

ACCEPTED MANUSCRIPT
5.4.1 N,N-Bis[(β-carboline-1-yl)methyl]butane-1,4-diamine (4a). Yellow oil was
1
obtained (0.33g, 75％). ESI-MS m/z: 449.1 [M+H]+. H NMR (300MHz, CDCl3): δ
10.25 (s, 2H, 2NH), 8.31 (d, J = 5.4 Hz, 2H, ArH), 8.09 (d, J = 7.8 Hz, 2H, ArH), 7.84
(d, J = 5.4 Hz, 2H, ArH), 7.52-7.45 (m, 4H, ArH), 7.27-7.22 (m, 2H, ArH), 4.35 (s,
4H, 2CH2), 2.77-2.59 (m, 4H, HNCH2CH2CH2CH2NH), 1.68-1.54 (m, 4H,
13
HNCH2CH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 143.5, 140.5, 138.0, 135.1,
129.1, 128.4, 121.9, 121.6, 119.8, 114.0, 112.0, 54.8, 49.9, 28.0. HRMS (ESI) calcd
for C28H34Cl6N6 [M+H]+ 449.2448, found 449.2446.
5.4.2 N,N-Bis[(β-carboline-1-yl)methyl]pentane-1,5-diamine (4b)：Yellow oil was
1
obtained (0.36g, 78％). ESI-MS m/z: 462.9 [M+H]+. H NMR (300MHz, CDCl3)：δ
10.37 (s, 2H, 2NH), 8.32 (d, J = 5.4 Hz, 2H, ArH), 8.07 (d, J = 7.8 Hz, 2H, ArH), 7.82
(d, J = 5.4 Hz, 2H, ArH), 7.52-7.41 (m, 4H, ArH), 7.26-7.18 (m, 2H, ArH), 4.33 (s,
4H, 2CH2), 2.57 (t, J = 6.6 Hz, 4H, HNCH2CH2CH2CH2CH2NH), 1.50-1.38 (m, 4H,
HNCH2CH2CH2CH2CH2NH), 1.33-1.20 (m, 2H, HNCH2CH2CH2CH2CH2NH). 13C
NMR (75MHz, CDCl3)：δ 143.6, 140.5, 138.0, 135.1, 129.1, 128.4, 121.9, 121.6,
119.8, 113.9, 111.9, 54.9, 50.0, 30.1, 25.3. HRMS (ESI) calcd for C29H36Cl6N6
[M+H]+ 463.2605, found 463.2596.
5.4.3 N,N-Bis[(9-methyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4c)
：Yellow
1
oil was obtained (0.30g, 65％). ESI-MS m/z: 476.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.30 (d, J = 5.1 Hz, 2H, ArH), 8.08 (d, J = 7.8 Hz, 2H, ArH), 7.84 (d, J =
5.1 Hz, 2H, ArH), 7.58 (t, J = 7.2 Hz, 2H, ArH), 7.42 (d, J = 7.8 Hz, 2H, ArH),
7.29-7.22 (m, 2H, ArH), 4.38 (s, 6H, 2NCH3), 4.18 (s, 4H, 2CH2), 2.88-2.78 (m, 4H,
16

ACCEPTED MANUSCRIPT
HNCH2CH2CH2CH2NH), 1.74-1.66 (m, 4H, HNCH2CH2CH2CH2NH). 13C NMR
(75MHz, CDCl3): δ 142.9, 142.2, 137.7, 135.6, 129.4, 128.3, 121.4, 121.1, 119.6,
113.9, 109.6, 54.3, 50.3, 32.1, 28.4. HRMS (ESI) calcd for C30H38Cl6N6 [M+H]+
477.2761, found 477.2764.
5.4.4 N,N-Bis[(9-methyl-β-carboline-1-yl)methyl]hexane-1,6-diamine (4d)
：Yellow
1
oil was obtained (0.33g, 66％). ESI-MS m/z: 506.1 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.31 (d, J = 5.1 Hz, 2H, ArH), 8.06 (d, J = 7.8 Hz, 2H, ArH), 7.83 (d, J =
5.1 Hz, 2H, ArH), 7.56 (t, J = 8.1 Hz, 2H, ArH), 7.40 (d, J = 8.1 Hz, 2H, ArH),
7.27-7.20 (m, 2H, ArH), 4.35 (s, 6H, 2NCH3), 4.16 (s, 4H, 2CH2), 2.78 (t, J = 6.9 Hz,
4H, HNCH2CH2CH2CH2CH2CH2NH), 1.64-1.52 (m, 4H, HNCH2CH2CH2CH2-
CH2CH2NH)，1.43-1.35 (m, 4H, HNCH2CH2CH2CH2CH2CH2NH). 13C NMR
(75MHz, CDCl3): δ 143.10, 142.2, 137.7, 135.7, 129.4, 128.3, 121.4, 121.1, 119.6,
113.9, 109.6, 54.5, 50.5, 32.1, 30.6, 27.7. HRMS (ESI) calcd for C32H42Cl6N6 [M+H]+
505.3074, found 505.3170.
5.4.5 N,N-Bis[(9-ethyl-β-carboline-1-yl)methyl]propyl-1,3-diamine (4e)
：Yellow oil
was obtained (0.28g, 56％). ESI-MS m/z: 491.1 [M+H]+. 1H NMR (300MHz, CDCl3):
δ 8.27 (d, J = 5.4 Hz, 2H, ArH), 8.05 (d, J = 7.5 Hz, 2H, ArH), 7.81 (d, J = 5.4 Hz, 2H,
ArH), 7.53 (t, J = 7.5 Hz, 2H, ArH), 7.37 (d, J = 8.4 Hz, 2H, ArH), 7.26-7.18 (m, 2H,
ArH), 4.65-4.52 (m, 4H, 2NCH2CH3), 4.37 (s, 4H, 2CH2), 2.97 (t, J = 6.6 Hz, 4H,
HNCH2CH2CH2NH), 1.97-1.86 (m, 2H, HNCH2CH2CH2NH), 1.41 (t, J = 7.2 Hz, 6H,
2NCH2CH3). 13C NMR (75MHz, CDCl3): δ 141.7, 141.4, 137.6, 134.6, 129.9, 128.5,
17

ACCEPTED MANUSCRIPT
121.6, 121.5, 119.9, 114.1, 109.8, 53.8, 49.0, 40.0, 30.0, 16.1. HRMS (ESI) calcd for
C31H40Cl6N6 [M+H]+ 491.2918, found 491.2913.
5.4.6 N,N-Bis[(9-ethyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4f)：Yellow oil
was obtained (0.28g, 55％). ESI-MS m/z: 504.9 [M+H]+. 1H NMR (300MHz, CDCl3):
δ 8.29 (d, J = 5.4 Hz, 2H, ArH), 8.03 (d, J = 7.5 Hz, 2H, ArH), 7.78 (d, J = 5.4 Hz, 2H,
ArH), 7.53 (t, J = 7.5 Hz, 2H, ArH), 7.39 (d, J = 8.1 Hz, 2H, ArH), 7.27-7.18 (m, 2H,
ArH), 4.68-4.53 (m, 4H, 2NCH2CH3), 4.32 (s, 4H, 2CH2), 2.88-2.80 (m, 4H,
HNCH2CH2CH2CH2NH), 1.75-1.66 (m, 4H, HNCH2CH2CH2CH2NH), 1.41 (t, J =
13
6.9 Hz, 6H, 2NCH2CH3); C NMR (75MHz, CDCl3) δ 142.1, 141.3, 137.7, 134.7,
129.8, 128.4, 121.6, 119.8, 114.0, 109.8, 54.2, 50.30, 40.0, 28.4, 16.1. HRMS (ESI)
calcd for C32H42Cl6N6 [M+H]+ 505.3074, found 505.3067.
5.4.7 N,N-Bis[(9-isopropyl-β-carboline-1-yl)methyl]propyl-1,3-diamine (4g)：Yellow
1
oil was obtained (0.28g, 53％). ESI-MS m/z: 518.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.26 (d, J = 5.1 Hz, 2H, ArH), 8.12 (d, J = 7.8 Hz, 2H, ArH), 7.87 (d, J =
5.1 Hz, 2H, ArH), 7.63 (d, J = 8.4 Hz, 2H, ArH), 7.48 (t, J = 8.4 Hz, 2H, ArH),
7.25-7.20 (m, 2H, ArH), 5.68-5.57 (m, 2H, 2NCH[CH3]2), 4.04 (s, 4H, 2CH2),
2.75-2.66 (m, 4H, HNCH2CH2CH2NH), 1.80-1.70 (m, 2H, HNCH2CH2CH2NH), 1.52
(d, J = 7.2 Hz, 12H, 2NCH[CH3]2). 13C NMR (75MHz, CDCl3): δ 141.5, 139.9, 137.1,
136.4, 129.7, 127.6, 122.7, 121.6, 119.3, 114.1, 113.5, 61.7, 52.6, 48.4, 23.9, 21.6.
HRMS (ESI) calcd for C33H44Cl6N6 [M+H]+ 519.3231, found 519.3296.
5.4.8
N,N-Bis[(9-isopropyl-β-carboline-1-yl)methyl]hexane-1,6-diamine (4h) ：
1
Yellow oil was obtained (0.50g, 89％). ESI-MS m/z: 560.9 [M+H]+. H NMR
18

ACCEPTED MANUSCRIPT
(300MHz, CDCl3) δ 8.31(d, J = 5.4 Hz, 2H, ArH), 8.12 (d, J = 7.8 Hz, 2H, ArH), 7.86
(d, J = 5.4 Hz, 2H, ArH), 7.70 (d, J = 8.4 Hz, 2H, ArH), 7.51 (t, J = 8.4 Hz, 2H, ArH),
7.28-7.20 (m, 2H, ArH), 5.74-5.62 (m, 2H, 2NCH[CH3]2), 4.31 (s, 4H, 2CH2), 2.78 (t,
J = 6.9 Hz, 2H, HNCH2CH2CH2CH2CH2CH2NH), 1.73 (d, J = 6.9 Hz, 12H,
2NCH[CH3]2), 1.63-1.52 (m, 4H, HNCH2CH2CH2CH2CH2CH2NH), 1.45-1.38 (m,
13
4H, HNCH2CH2CH2CH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 142.7, 140.1,
137.5, 135.8, 129.6, 127.6, 122.9, 121.7, 119.4, 113.8, 113.5, 55.9, 50.5, 48.8, 30.6,
27.8, 21.8. HRMS (ESI) calcd for C36H50Cl6N6 [M+H]+ 561.3700, found 561.3703.
5.4.9 N,N-Bis[(9-isobutyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4i)：Yellow
1
oil was obtained (0.42g, 74％). ESI-MS m/z: 562.1 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.32 (d, J = 5.1 Hz, 2H, ArH), 8.08 (d, J = 7.8 Hz, 2H, ArH), 7.86 (d, J
=5.1 Hz, 2H, ArH), 7.53 (t, J = 7.8 Hz, 2H, ArH), 7.46 (d, J = 8.4 Hz, 2H, ArH),
7.28-7.20 (m, 2H, ArH), 4.39 (d, J = 7.5 Hz, 4H, 2NCH2CH[CH3]2), 4.33 (s, 4H,
2CH2), 2.86-2.79 (m, 4H, HNCH2CH2CH2CH2NH), 2.32-2.17 (m, 2H,
2NCH2CH[CH3]2), 1.30-1.24 (m, 4H, HNCH2CH2CH2CH2NH), 0.93 (d, J =6.6 Hz,
13
12H, 2NCH2CH[CH3]2). C NMR (75MHz, CDCl3): δ 142.4, 142.2, 137.7, 135.0,
129.8, 128.1, 121.4, 121.2, 119.6, 113.9, 110.7, 54.2, 52.1, 50.3, 31.0, 28.5, 20.7.
HRMS (ESI) calcd for C36H50Cl6N6 [M+H]+ 561.3700, found 561.3699.
5.4.10 N,N-Bis[(9-isobutyl-β-carboline-1-yl)methyl]hexane-1,6-diamine (4j)：Yellow
1
oil was obtained (0.46g, 78％). ESI-MS m/z: 588.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.36 (d, J = 5.4 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.89 (d, J
=5.4 Hz, 2H, ArH), 7.55 (t, J = 7.8 Hz, 2H, ArH), 7.47 (d, J = 8.4 Hz, 2H, ArH),
19

ACCEPTED MANUSCRIPT
7.28-7.22 (m, 2H, ArH), 4.42 (d, J = 7.5 Hz, 4H, 2NCH2CH[CH3]2), 4.33 (s, 4H,
2CH2), 2.78 (t, J = 6.9 Hz, 4H, HNCH2CH2CH2CH2CH2CH2NH), 2.34-2.22 (m, 2H,
2NCH2CH[CH3]2), 1.66-1.53 (m, 4H, HNCH2CH2CH2CH2CH2CH2NH), 1.46-1.36
(m, 4H, HNCH2CH2CH2CH2CH2CH2NH), 0.95 (d,
J
=6.6 Hz, 12H,
13
2NCH2CH[CH3]2). C NMR (75MHz, CDCl3): δ 142.2, 141.3, 137.6, 134.9, 129.9,
128.2, 121.4, 121.1, 119.7, 114.0, 110.7, 53.5, 52.1, 50.1, 30.9, 29.9, 27.4, 20.6.
HRMS (ESI) calcd for C38H54Cl6N6 [M+H]+ 589.4013, found 589.4007.
5.4.11 N,N-Bis (9-butyl-β-carboline-1-yl)methyl]propane-1,3-diamine (4k)：Yellow
1
oil was obtained (0.26g, 48％). ESI-MS m/z: 546.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.31 (d, J = 5.1 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.87 (d, J
=5.1 Hz, 2H, ArH), 7.55 (t, J = 7.8 Hz, 2H, ArH), 7.47 (d, J = 8.4 Hz, 2H, ArH),
7.29-7.22 (m, 2H, ArH), 4.56 (t, J = 7.8 Hz, 2H, 2NCH2[CH2]2CH3), 4.33 (s, 4H,
2CH2), 2.92 (t, J = 6.6 Hz, 4H, HNCH2CH2CH2NH), 1.90-1.78 (m, 6H,
2NCH2CH2CH2CH3, HNCH2CH2CH2NH), 1.51-1.37 (m, 4H, 2NCH2CH2CH2CH3),
13
0.97 (t, J = 7.2 Hz, 6H, 2NCH2[CH2]2CH3). C NMR (75MHz, CDCl3): δ 142.6,
141.7, 137.7, 134.9, 129.8, 128.3, 121.5, 121.4, 119.7, 114.1, 110.0, 54.7, 49.1, 45.9,
33.3, 31.0, 20.8, 14.4. HRMS (ESI) calcd for C35H48Cl6N6 [M+H]+ 547.3544, found
547.3536.
5.4.12 N,N-Bis[(9-butyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4l)
：Yellow
1
oil was obtained (0.33g, 59％). ESI-MS m/z: 560.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.29 (d, J = 5.1 Hz, 2H, ArH), 8.07 (d, J = 7.8 Hz, 2H, ArH), 7.82 (d, J
=5.1 Hz, 2H, ArH), 7.56 (t, J = 7.8 Hz, 2H, ArH), 7.44 (d, J = 8.4 Hz, 2H, ArH),
20

ACCEPTED MANUSCRIPT
7.26-7.21 (m, 2H, ArH), 4.56 (t, J = 7.2 Hz, 2H, 2NCH2[CH2]2CH3), 4.34 (s, 4H,
2CH2), 2.90-2.82 (m, 4H, HNCH2CH2CH2CH2NH), 1.87-1.78 (m, 4H,
2NCH2CH2CH2CH3), 1.77-1.67 (m, 4H, HNCH2CH2CH2CH2NH), 1.52-1.37 (m, 4H,
2NCH2CH2CH2CH3), 0.98 (t, J = 6.9 Hz, 6H, 2NCH2[CH2]2CH3). 13C NMR (75MHz,
CDCl3): δ 142.0, 141.7, 137.6, 134.8, 129.7, 128.3, 121.5, 121.4, 119.7, 114.0, 109.9,
54.1, 50.3, 45.1, 33.2, 28.5, 20.7, 14.3. HRMS (ESI) calcd for C36H50Cl6N6 [M+H]+
561.3700, found 561.3708.
5.4.13 N,N-Bis[(9-butyl-β-carboline-1-yl)methyl]pentane-1,5-diamine (4m)：Yellow
1
oil was obtained (0.37g, 64％). ESI-MS m/z: 575.1 [M+H]+. H NMR (300MHz,
CDCl3)：δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.88 (d, J
=5.1 Hz, 2H, ArH), 7.57 (t, J = 7.8 Hz, 2H, ArH), 7.44 (d, J = 8.4 Hz, 2H, ArH),
7.29-7.22 (m, 2H, ArH), 4.60 (t, J = 8.1 Hz, 4H, 2NCH2[CH2]2CH3), 4.33 (s, 4H,
2CH2), 2.81 (t, J = 6.9 Hz, 4H, HNCH2CH2CH2CH2CH2NH), 1.91-1.79 (m, 4H,
2NCH2CH2CH2CH3), 1.70-1.56 (m, 4H, HNCH2CH2CH2CH2CH2NH), 1.54-1.40 (m,
6H, 2NCH2CH2CH2CH3, HNCH2CH2CH2CH2CH2NH), 1.00 (t, J = 7.2 Hz, 6H,
2NCH2[CH2]2CH3). 13C NMR (75MHz, CDCl3): δ 142.6, 141.8, 137.7, 135.0, 129.8,
128.3, 121.5, 119.7, 114.0, 110.0, 54.5, 50.5, 45.1, 33.3, 30.5, 25.7, 20.7, 14.3. HRMS
(ESI) calcd for C37H52Cl6N6 [M+H]+ 575.3857, found 575.3856.
5.4.14 N,N-Bis[(9-butyl-β-carboline-1-yl)metyl]hexane-1,6-diamine (4n)：Yellow oil
1
was obtained (0.40g, 68％). ESI-MS m/z: 590.2 [M+H]+. H NMR (300MHz,
CDCl3)：δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.11 (d, J = 7.8 Hz, 2H, ArH), 7.88 (d, J
=5.1 Hz, 2H, ArH), 7.57 (t, J = 7.8 Hz, 2H, ArH), 7.46 (d, J = 8.4 Hz, 2H, ArH),
21

ACCEPTED MANUSCRIPT
7.29-7.22 (m, 2H, ArH), 4.61 (t, J = 7.5 Hz, 4H, 2NCH2[CH2]2CH3), 4.32 (s, 4H,
2CH2), 2.79 (t, J = 6.9 Hz, 4H, HNCH2CH2CH2CH2CH2CH2NH), 1.90-1.79 (m, 4H,
2NCH2CH2CH2CH3), 1.66-1.54 (m, 4H, HNCH2CH2CH2CH2CH2CH2NH), 1.54-1.37
(m, 8H, 2NCH2CH2CH2CH3, HNCH2CH2CH2CH2CH2CH2NH), 1.00 (t, J = 7.5 Hz,
13
6H, 2NCH2[CH2]2CH3). C NMR (75MHz, CDCl3): δ 142.8, 141.7, 137.7, 135.0,
129.8, 128.3, 121.5, 121.5, 119.7, 114.0, 110.0, 54.7, 50.6, 45.1, 33.3, 30.6, 27.8, 20.8,
14.4. HRMS (ESI) calcd for C38H54Cl6N6 [M+H]+ 589.4013, found 589.4014.
5.4.15 N,N-Bis[(9-hexyl-β-carboline-1-yl)methyl]propyl-1,3-diamine (4o)
：Yellow
1
oil was obtained (0.43g, 72％). ESI-MS m/z: 603.0 [M+H]+. H NMR (300MHz,
CDCl3) δ 8.31 (d, J = 5.4 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.86 (d, J =5.4
Hz, 2H, ArH), 7.56 (t, J = 7.8 Hz, 2H, ArH), 7.40 (d, J = 8.4 Hz, 2H, ArH), 7.29-7.22
(m, 2H, ArH), 4.54 (t, J = 7.8 Hz, 4H, 2NCH2[CH2]4CH3), 4.32 (s, 4H, 2CH2), 2.92 (t,
J = 6.9 Hz, 4H, HNCH2CH2CH2NH), 1.92-1.76 (m, 6H, 2NCH2CH2[CH2]3CH3,
HNCH2CH2CH2NH), 1.48-1.21 (m, 12H, 2NCH2CH2[CH2]3CH3), 0.87 (t, J = 6.6 Hz,
13
6H, 2NCH2[CH2]4CH3). C NMR (75MHz, CDCl3): δ 137.9, 137.0, 133.0, 130.2,
125.1, 123.6, 116.8, 115.0, 109.3, 105.2, 49.9, 44.3, 40.6, 27.2, 26.4, 26.3, 22.4, 18.2,
9.6. HRMS (ESI) calcd for C39H56Cl6N6 [M+H]+ 603.4170, found 603.4172.
5.4.16 N,N-Bis[(9-hexyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4p)：Yellow
1
oil was obtained (0.46g, 75％). ESI-MS m/z: 616.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.33 (d, J = 5.4 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.87 (d, J
=5.4 Hz, 2H, ArH), 7.55 (t, J = 7.8 Hz, 2H, ArH), 7.43 (d, J = 8.4 Hz, 2H, ArH),
7.28-7.22 (m, 2H, ArH), 4.57 (t, J = 8.1 Hz, 4H, 2NCH2[CH2]4CH3), 4.32 (s, 4H,
22

ACCEPTED MANUSCRIPT
2CH2), 2.88-2.79 (m, 4H, HNCH2CH2CH2CH2NH), 1.91-1.78 (m, 4H,
2NCH2CH2[CH2]3CH3), 1.73-1.63 (m, 4H, HNCH2CH2CH2CH2NH), 1.51-1.24 (m,
13
12H, 2NCH2CH2[CH2]3CH3), 0.89 (t, J = 6.6 Hz, 6H, 2NCH2[CH2]4CH3). C NMR
(75MHz, CDCl3): δ 142.7, 141.7, 137.7, 134.9, 129.8, 128.3, 121.5, 121.5, 119.7,
114.0, 110.0, 54.7, 50.5, 45.4, 32.0, 31.2, 28.6, 27.1, 23.0, 14.5. HRMS (ESI) calcd
for C40H58Cl6N6 [M+H]+ 617.4326, found 617.4330.
5.4.17 N,N-Bis[(9-hexyl-β-carboline-1-yl)metyl]pentane-1,5-diamine (4q)
：Yellow
1
oil was obtained (0.40g, 71％). ESI-MS m/z: 632.3 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.34 (d, J = 5.4 Hz, 2H, ArH), 8.11 (d, J = 7.8 Hz, 2H, ArH), 7.88 (d, J
=5.4 Hz, 2H, ArH), 7.57 (t, J = 7.8 Hz, 2H, ArH), 7.44 (d, J = 8.4 Hz, 2H, ArH),
7.28-7.24 (m, 2H, ArH), 4.59 (t, J = 7.8 Hz, 4H, 2NCH2[CH2]4CH3), 4.32 (s, 4H,
2CH2), 2.81 (t, J = 6.6 Hz, 4H, HNCH2CH2CH2CH2CH2NH), 1.92-1.79 (m, 4H,
NCH2CH2[CH2]3CH3), 1.68-1.55 (m, 4H, HNCH2CH2CH2CH2CH2NH), 1.53-1.25 (m,
14H, 2NCH2CH2[CH2]3CH3, HNCH2CH2CH2CH2CH2NH), 0.90 (t, J = 6.6 Hz, 6H,
2NCH2[CH2]4CH3). 13C NMR (75MHz, CDCl3): δ 142.7, 141.7, 137.7, 134.9, 129.7,
128.3, 121.5, 121.4, 119.7, 114.0, 109.9, 54.7, 50.6, 45.3, 31.9, 31.1, 30.6, 27.1, 25.7,
23.0, 14.5. HRMS (ESI) calcd for C41H60Cl6N6 [M+H]+ 631.4483, found 631.4485.
5.4.18 N,N-Bis[(9-hexyl-β-carboline-1-yl)methyl]hexane-1,6-diamine (4r)：Yellow
1
oil was obtained (0.53g, 82％). ESI-MS m/z: 645.3 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.34 (d, J = 5.4 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.87 (d, J
=5.4 Hz, 2H, ArH), 7.57 (t, J = 7.8 Hz, 2H, ArH), 7.45 (d, J = 8.1 Hz, 2H, ArH),
7.2-7.22 (m, 2H, ArH), 4.60 (t, J = 8.4 Hz, 4H, 2NCH2[CH2]4CH3), 4.32 (s, 4H,
23

ACCEPTED MANUSCRIPT
2CH2), 2.80 (t, J = 6.9 Hz, 4H, HNCH2CH2CH2CH2CH2CH2NH), 1.92-1.80 (m, 4H,
NCH2CH2[CH2]3CH3), 1.66-1.54 (m, 4H, HNCH2CH2CH2CH2CH2CH2NH),
1.53-1.28 (m, 16H, 2NCH2CH2[CH2]3CH3, HNCH2CH2CH2CH2CH2CH2NH), 0.90 (t,
J = 6.9 Hz, 6H, 2NCH2[CH2]4CH3). 13C NMR (75MHz, CDCl3)： δ 141.7, 137.5,
134.7, 129.8, 128.3, 121.5, 121.3, 119.7, 114.0, 109.9, 53.9, 50.3, 45.3, 31.9, 31.1,
30.2, 27.6, 27.0, 22.9, 14.4. HRMS (ESI) calcd for C42H62Cl6N6 [M+H]+ 645.4639,
found 645.4644.
5.4.19 N,N-Bis[(9-octyl-β-carboline-1-yl)methyl]butane-1,4-diamine (4s)：Yellow oil
was obtained (0.41g, 61％). ESI-MS m/z: 672.9 [M+H]+. 1H NMR (300MHz, CDCl3):
δ 8.33 (d, J = 5.1 Hz, 2H, ArH), 8.07 (d, J = 7.8 Hz, 2H, ArH), 7.84 (d, J =5.1 Hz, 2H,
ArH), 7.55 (t, J = 7.8 Hz, 2H, ArH), 7.41 (d, J = 8.4 Hz, 2H, ArH), 7.26-7.20 (m, 2H,
ArH), 4.55 (t, J = 7.8 Hz, 4H, 2NCH2[CH2]6CH3), 4.33 (s, 4H, 2CH2), 2.89-2.81 (m,
4H, HNCH2CH2CH2CH2NH), 1.90-1.77 (m, 4H, 2NCH2CH2[CH2]5CH3), 1.74-1.65
(m, 4H, HNCH2CH2CH2CH2NH), 1.48-1.20 (m, 20H, 2NCH2CH2[CH2]5CH3), 0.88 (t,
J = 5.4 Hz, 6H, 2NCH2[CH2]6CH3). 13C NMR (75MHz, CDCl3): δ 142.5, 141.7,
137.7, 134.9, 129.7, 128.3, 121.5, 119.7, 113.9, 109.1, 54.5, 50.5, 45.3, 32.1, 31.1,
29.7, 29.6, 28.6, 27.4, 23.0, 14.5. HRMS (ESI) calcd for C44H66Cl6N6 [M+H]+
673.4952, found 673.4954.
5.4.20 N,N-Bis[(9-octyl-β-carboline-1-yl)methyl]pentane-1,5-diamine (4t)：Yellow
1
oil was obtained (0.46g, 66％). ESI-MS m/z: 686.9 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.10 (d, J = 7.8 Hz, 2H, ArH), 7.88 (d, J
=5.1 Hz, 2H, ArH), 7.57 (t, J = 7.8 Hz, 2H, ArH), 7.44 (d, J = 8.4 Hz, 2H, ArH),
24

ACCEPTED MANUSCRIPT
7.29-7.22 (m, 2H, ArH), 4.59 (t, J = 7.8 Hz, 4H, 2NCH2[CH2]6CH3), 4.33 (s, 4H,
2CH2), 2.81 (t, J = 6.9 Hz, 4H, HNCH2CH2CH2CH2CH2NH), 1.92-1.80 (m, 4H,
2NCH2CH2[CH2]5CH3), 1.68-1.55 (m, 4H, HNCH2CH2CH2CH2CH2NH), 1.54-1.20
(m, 22H, 2NCH2CH2[CH2]5CH3, HNCH2CH2CH2CH2CH2NH), 0.88 (t, J = 6.0 Hz,
13
6H, 2NCH2[CH2]6CH3). C NMR (75MHz, CDCl3): δ 142.7, 141.8, 137.7, 135.0,
129.8, 128.3, 121.5, 119.7, 114.0, 110.0, 54.6, 50.5, 45.4, 32.1, 31.2, 30.6, 29.8, 29.6,
27.5, 25.7, 23.0, 14.4. HRMS (ESI) calcd for C45H68Cl6N6 [M+H]+ 687.5109, found
687.5114.
5.4.21 N,N-Bis[(9-benzyl-β-carboline-1-yl)methyl]propane-1,3-diamine (4u)
：
1
Yellow oil was obtained (0.30g, 49％). ESI-MS m/z: 614.9 [M+H]+. H NMR
(300MHz, CDCl3): δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.16 (d, J = 7.8 Hz, 2H, ArH),
7.93 (d, J =5.1 Hz, 2H, ArH), 7.52 (t, J = 7.8 Hz, 2H, ArH), 7.36-7.14 (m, 10H, ArH),
6.94 (d, J = 6.0 Hz, 4H, ArH), 5.94 (s, 4H, 2NCH2Ph), 4.07 (s, 4H, 2CH2), 2.74 (t, J =
13
6.6 Hz, 4H, HNCH2CH2CH2NH), 1.74-1.62 (m, 2H, HNCH2CH2CH2NH). C NMR
(75MHz, CDCl3): δ 143.0, 142.2, 138.8, 138.2, 135.8, 129.2, 128.7, 127.4, 125.4,
121.6, 120.2, 114.3, 110.2, 54.6, 48.8, 48.5, 30.8. HRMS (ESI) calcd for C41H44Cl6N6
[M+H]+ 615.3231, found 615.3229.
5.2.22 N,N-Bis[(9-benzyl-β-carboline-1-yl)methyl]hexane-1,6-diamine (4v)：Yellow
1
oil was obtained (0.49g, 75％). ESI-MS m/z: 656.8 [M+H]+. H NMR (300MHz,
CDCl3): δ 8.38 (d, J = 5.1 Hz, 2H, ArH), 8.16 (d, J = 7.8 Hz, 2H, ArH), 7.94 (d, J
=5.1 Hz, 2H, ArH), 7.53 (t, J = 7.8 Hz, 2H, ArH), 7.38-7.19 (m, 10H, ArH), 6.98 (d, J
= 6.6 Hz, 4H, ArH), 6.00 (s, 4H, 2NCH2Ph), 4.08 (s, 4H, 2CH2), 2.66 (t, J = 6.9 Hz,
25

ACCEPTED MANUSCRIPT
4H,
HNCH2CH2CH2CH2CH2CH2NH),
1.54-1.43
1.37-1.30
(m,
4H,
4H,
HNCH2CH2CH2CH2CH2CH2NH),
(m,
HNCH2CH2CH2CH2CH2CH2NH). 13C NMR (75MHz, CDCl3): δ 143.2, 142.3, 138.9,
138.2, 135.9, 130.0, 129.2, 128.7, 127.5, 125.4, 121.6, 120.2, 114.2, 110.2, 54.5, 50.4,
48.6, 30.5, 27.7. HRMS (ESI) calcd for C44H50Cl6N6 [M+H]+ 657.3700, found
657.3715.
5.2.23 N,N-Bis[[9-(4-fluorobenzyl)-β-carboline-1-yl]methyl]propane-1,3- diamine
(4w)：
Yellow oil was obtained (0.35g, 53％). ESI-MS m/z: 650.9 [M+H]+. 1H NMR
(300MHz, CDCl3): δ 8.29 (d, J = 5.1 Hz, 2H, ArH), 8.14 (d, J = 7.8 Hz, 2H, ArH),
7.90 (d, J =5.1 Hz, 2H, ArH), 7.52 (t, J = 7.8 Hz, 2H, ArH), 7.31-7.25 (m, 4H, ArH),
6.97-6.87 (m, 8H, ArH), 5.87 (s, 4H, 2NCH2Ph[4-F]), 4.11 (s, 4H, 2CH2), 2.79 (t, J =
13
6.3 Hz, 4H, HNCH2CH2CH2NH), 1.79-1.67 (m, 2H, HNCH2CH2CH2NH). C NMR
(75MHz, CDCl3): δ 163.7, 160.4, 142.9, 142.0, 138.3, 135.7, 134.5, 130.0, 128.7,
127.1, 127.0, 121.6, 120.3, 116.2, 115.9, 114.2, 110.0, 54.5, 48.1, 47.9, 40.7, 34.0.
HRMS (ESI) calcd for C41H42Cl6F2N6 [M+H]+ 651.3042, found 651.3045.
5.2.24
(4x)
N,N-Bis[[9-(4-fluorobenzyl)-β-carboline-1-yl]methyl]butane-1,4-diamine
1
：
Yellow oil was obtained (0.42g, 63％). ESI-MS m/z: 665.9 [M+H]+. H NMR
(300MHz, CDCl3): δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.14 (d, J = 7.8 Hz, 2H, ArH),
7.91 (d, J =5.1 Hz, 2H, ArH), 7.53 (t, J = 7.8 Hz, 2H, ArH), 7.34-7.25 (m, 4H, ArH),
6.92 (d, J =7.2 Hz, 8H, ArH), 5.92 (s, 4H, 2NCH2Ph[4-F]), 4.07 (s, 4H, 2CH2),
2.72-2.66
(m,
4H,
HNCH2CH2CH2CH2NH),
1.60-1.54
(m,
4H,
13
HNCH2CH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 163.7, 160.5, 142.6, 142.1,
26

ACCEPTED MANUSCRIPT
138.3, 135.6, 134.4, 130.1, 128.8, 127.1, 127.0, 126.8, 121.7, 121.6, 120.4, 120.2,
116.2, 116.0, 114.3, 110.0, 54.3, 50.2, 48.0, 28.4. HRMS (ESI) calcd for
C42H44Cl6F2N6 [M+H]+ 665.3199, found 665.3206.
5.2.25 N,N-Bis[[9-(3-chlorobenzyl)-β-carboline-1-yl]methyl]propane-1,3-diamine
1
(4y)：
Yellow oil was obtained (0.35g, 51％). ESI-MS m/z: 684.6 [M+H]+. H NMR
(300MHz, CDCl3): δ 8.34 (d, J = 5.1 Hz, 2H, ArH), 8.13 (d, J = 7.8 Hz, 2H, ArH),
7.91 (d, J =5.1 Hz, 2H, ArH), 7.51 (t, J = 7.8 Hz, 2H, ArH), 7.32-7.24 (m, 4H, ArH),
7.19-7.06 (m, 4H, ArH), 7.00 (s, 2H, ArH), 6.87 (d, J = 7.5 Hz, 2H, ArH), 5.92 (s, 4H,
2NCH2Ph[3-Cl]), 4.07 (s, 4H, 2CH2), 2.77 (t, J = 6.6 Hz, 4H, HNCH2CH2CH2NH),
13
1.74-1.64 (m, 2H, HNCH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 142.8, 142.1,
141.2, 138.4, 135.8, 135.1, 130.5, 130.1, 128.9, 127.7, 125.7, 123.7, 121.7, 121.6,
120.5, 114.4, 110.0, 54.5, 48.8, 48.2, 30.5. HRMS (ESI) calcd for C41H40Cl8N6
[M+H]+ 683.2451, found 683.2442.
5.4.26
(4z)
N,N-Bis[[9-(3-chlorobenzyl)-β-carboline-1-yl]methyl]pentane-1,5-diamine
1
：
Yellow oil was obtained (0.37g, 53％). ESI-MS m/z: 710.5 [M+H]+. H NMR
(300MHz, CDCl3): δ 8.38 (d, J = 5.1 Hz, 2H, ArH), 8.16 (d, J = 7.8 Hz, 2H, ArH),
7.95 (d, J =5.1 Hz, 2H, ArH), 7.50 (t, J = 7.8 Hz, 2H, ArH), 7.34-7.24 (m, 4H, ArH),
7.20-7.13 (m, 4H, ArH), 7.03 (s, 2H, ArH), 6.84 (d, J = 6.3 Hz, 2H, ArH), 6.00 (s, 4H,
2NCH2Ph[3-Cl]), 4.05 (s, 4H, 2CH2), 2.67 (t,
J
=
6.6 Hz, 4H,
13
HNCH2CH2CH2CH2CH2NH), 1.55-1.25 (m, 6H, HNCH2CH2CH2CH2CH2NH). C
NMR (75MHz, CDCl3) δ 143.1, 142.1, 141.2, 138.4, 135.2, 130.5, 130.1, 128.8,
27

ACCEPTED MANUSCRIPT
127.7, 125.7, 123.6, 121.7, 120.4, 114.3, 110.0, 54.8, 50.3, 48.3, 30.5, 25.6. HRMS
(ESI) calcd for C43H46Cl8N6 [M+H]+ 711.2764, found 711.2781.
5.4.27 N,N-Bis[[9-(3-phenylpropyl)-β-carboline-1-yl]methyl]propane-1,3-diamine
(4aa)
：
Yellow oil was obtained (0.33g, 50％). ESI-MS m/z: 670.7 [M+H]+. 1H NMR
(300MHz, CDCl3): δ 8.30 (d, J = 5.1 Hz, 2H, ArH), 8.09 (d, J = 7.8 Hz, 2H, ArH),
7.85 (d, J =5.1 Hz, 2H, ArH), 7.52 (t, J = 7.8 Hz, 2H, ArH), 7.30-7.12 (m, 14H, ArH),
4.57 (t, J = 8.1 Hz, 4H, 2NCH2CH2CH2Ph), 4.19 (s, 4H, 2CH2), 2.78-2.67 (m, 8H,
2NCH2CH2CH2Ph, HNCH2CH2CH2NH), 2.20-2.08 (m, 4H, 2NCH2CH2CH2Ph),
13
1.83-1.68 (m, 2H, HNCH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 142.8, 141.7,
141.0, 137.8, 135.0, 129.9, 128.8, 128.6, 128.4, 126.5, 121.6, 119.8, 114.1, 110.0,
54.8, 48.8, 44.7, 33.6, 32.3, 31.0. HRMS (ESI) calcd for C45H46Cl6N6 [M+H]+
671.3857, found 671.3866.
5.4.28
N,N-Bis[[9-(3-phenylpropyl)-β-carboline-1-yl]methyl]butane-1,4-diamine
(4ab)：Yellow oil was obtained (0.38g, 56％). ESI-MS m/z: 685.1[M+H]+. 1H NMR
(300MHz, CDCl3): δ 8.70 (s, 2H, ArH), 8.11 (d, J = 7.8 Hz, 2H, ArH), 7.95 (s, 2H,
ArH), 7.52 (t, J = 6.9 Hz, 2H, ArH), 7.36-7.12 (m, 14H, ArH), 4.34 (t, J = 7.2 Hz, 4H,
2NCH2CH2CH2Ph), 4.08 (s, 4H, 2CH2), 2.79-2.67 (m, 8H, 2NCH2CH2CH2Ph，
HNCH2CH2CH2CH2NH), 2.29-2.17 (m, 4H, 2NCH2CH2CH2Ph), 1.70-1.64 (m, 4H,
13
HNCH2CH2CH2CH2NH). C NMR (75MHz, CDCl3): δ 149.0, 141.6, 140.8, 135.7,
131.5, 131.4, 129.3, 128.8, 128.4, 126.4, 122.2, 121.4, 119.7, 113.3, 109.6, 56.0, 50.0,
43.0, 33.5, 30.6, 28.5. HRMS (ESI) calcd for C46H54Cl6N6 [M+H]+ 685.4013, found
685.4005.
28