Synthesis and in vitro and in vivo evaluation of antimalarial polyamines

Article abstract of DOI:10.1016/j.ejmech.2013.07.055

We recently reported that 1,14-diphenylacetamide derivatives of spermine exhibit potent nM in vitro growth inhibition properties of Plasmodium falciparum. In an effort to expand the structure-activity relationship of this compound class towards malaria, we have prepared and biologically tested a library that includes benzamide and 3-phenylpropanamide 'capping acid' groups, and polyamines that include spermine (PA3-4-3) and chain extended analogues PA3-8-3 and PA3-12-3. 2-Hydroxy and 2,5-dimethoxy analogues were typically found to exhibit the most potent activity towards the dual drug resistant strain K1 of P. falciparum with IC₅₀'s in the range of 1.3-9.5 nM, and selectivity indices (SI) of 42,300 to 4880. In vivo evaluation of three analogues against Plasmodium berghei was undertaken, with one demonstrating a modest 27.9% reduction in parasitaemia.

Full text of DOI:10.1016/j.ejmech.2013.07.055

European Journal of Medicinal Chemistry 69 (2013) 22e31
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and in vitro and in vivo evaluation of antimalarial
polyamines
,
,
Lydia P.P. Liewa, A. Norrie Pearce a, Marcel Kaiser b c, Brent R. Copp a
*
a School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
b Swiss Tropical and Public Health Institute, Socinstrasse 57, PO Box, CH-4002 Basel, Switzerland
c University of Basel, CH-4003 Basel, Switzerland
a r t i c l e i n f o
a b s t r a c t
Article history:
We recently reported that 1,14-diphenylacetamide derivatives of spermine exhibit potent nM in vitro
growth inhibition properties of Plasmodium falciparum. In an effort to expand the structureeactivity
relationship of this compound class towards malaria, we have prepared and biologically tested a library
that includes benzamide and 3-phenylpropanamide ‘capping acid’ groups, and polyamines that include
spermine (PA3-4-3) and chain extended analogues PA3-8-3 and PA3-12-3. 2-Hydroxy and 2,5-dimethoxy
analogues were typically found to exhibit the most potent activity towards the dual drug resistant strain
K1 of P. falciparum with IC50’s in the range of 1.3e9.5 nM, and selectivity indices (SI) of 42,300 to 4880.
In vivo evaluation of three analogues against Plasmodium berghei was undertaken, with one demon-
strating a modest 27.9% reduction in parasitaemia.
Received 9 May 2013
Received in revised form
28 July 2013
Accepted 30 July 2013
Available online 14 August 2013
Keywords:
Malaria
Polyamine
Natural product
New orthidine F analogues
Ó 2013 Elsevier Masson SAS. All rights reserved.
1. Introduction
well as the effect of variation, to smaller fragments, of the poly-
amine core. Two analogues, 2-hydroxyphenylacetamide 2 and 2,5-
Historically, natural products have acted as either a rich source
of human therapeutics or as templates from which therapeutics
are developed [1]. In the specific case of malaria, the plant natural
product quinine (Cinchona sp.) spawned the development of
chloroquine, primaquine and mefloquine [2] while investigation of
the active principals of the Chinese plant (Artemisia annua) led
ultimately to the introduction of artemisinin and related semi-
synthetic antimalarials [2,3]. While chloroquine and artemisinin-
type endoperoxides continue to be used in the front-line treat-
ment of malaria, the increased incidence of resistance [4] prompts
the need to develop new mode-of-action antimalarials. The ma-
rine environment is proving to be a useful reservoir from which to
discover new chemical scaffolds possessing antimalarial proper-
ties [5e8].
dimethoxyphenylacetamide 3, were found to exhibit significantly
more pronounced activity towards Plasmodium falciparum, with
IC50 8.6 nM and 19 nM respectively, than orthidine F (1) (IC50
890 nM). In addition, like 1 (L6 IC50 > 120
found to be relatively non-toxic towards the L6 rat myoblast cell
line, with IC50’s of >130 M and 88 M respectively [10].Fig. 1
mM), both 2 and 3 were
m
m
In continuation of our interest in this class of antimalarial agent,
we now report the synthesis of a new library of polyamine di-
amides that explore further polyamine fragments and alternative
‘capping acids’. All analogues were evaluated for antimalarial ac-
tivity against the K1 dual drug resistant strain of P. falciparum and
for cytotoxicity towards the non-malignant L6 rat myoblast cell
line. Three analogues were also tested for their in vivo antimalarial
activity against Plasmodium berghei in mice.
As part of our ongoing search for new antimalarial lead com-
pounds [9], we recently reported the discovery and preliminary
assessment of structureeantimalarial activity for the polyamine
marine natural product orthidine F (1) and new synthesized
structural analogues [10,11]. The study evaluated the influence on
biological activity of a variety of phenylacetic acid ‘capping acids’ as
2. Chemistry
Using similar methodology previously reported by us for the
preparation of spermine-phenylacetamide analogues [10,11], reac-
tion of spermine with three benzoic acid derivatives (benzoic acid,
2-hydrobenzoic acid and 2,5-dimethoxybenzoic acid) and four 3-
phenylpropanoic acid derivatives (3-phenylpropanoic acid, 3-(2-
hydroxyphenyl)propanoic acid, 3-(2,5-dimethoxyphenyl)propanoic
acid and 3-(3,4-dimethoxyphenyl)propanoic acid) using PyBOP as
* Corresponding author. Tel.: þ64 9 923 8284; fax: þ64 9 373 7422.
E-mail address: b.copp@auckland.ac.nz (B.R. Copp).
0223-5234/$ e see front matter Ó 2013 Elsevier Masson SAS. All rights reserved.
http://dx.doi.org/10.1016/j.ejmech.2013.07.055

L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
23
Fig. 1. Lead antimalarial polyamine structures.
the coupling agent afforded, after chromatographic purification,
analogues 4e10 in yields of 47%, 28%, 59%, 92%, 84%, 14% and 72%,
respectively (Fig. 2).
We next sought to explore the influence of polyamines of
extended length on antimalarial activity with the preparation of
spermine analogues bearing longer central hydrocarbon chains.
The tert-butylcarbamate protected octane-1,8-bis(3-aminopropyl)
polyamine 14 required for the preparation of analogues 15e20 was
synthesised by a modification of previously reported methods
[12,13]. Reaction of 1,8-diaminooctane (11) with two equivalents of
acrylonitrile (to give 12), followed by Boc protection (13) and
reduction (NieAl alloy) gave the desired bis-tert-butoxylcarbamate
protected tetraamine 14 (Scheme 1). Subsequent reaction of 14
with phenylacetic acid, 2-hydrophenylacetic acid and 2,5-
dimethoxyphenylacetic acid, again using PyBOP as a coupling
agent, afforded Boc protected diamides 15e17 in yields of 75%, 55%
and 64% respectively. Removal of the Boc groups with TFA in CH2Cl2
gave tetraamineediamides 18e20 as TFA salts.
Scheme 1. Preparation of polyamines 15e20. Reagents and conditions: (i) acryloni-
trile, EtOH, N2, reflux, 3h. (ii) di-tert-butyl dicarbonate, Et3N, CH2Cl2, N2, 22.5 h (iii)
LiOH, 10% Pd/C, 50% NieAl alloy, H2, 50 ꢀC, 21 h (iv) carboxylic acid (2 equiv), PyBOP,
DMF, Et3N, N2, 23 h (v) CH2Cl2, TFA, N2, 2 h.
The preparation of a further set of chain extended polyamine
analogues made use of the previously reported Boc protected
dodecane-1,12-(3-aminopropyl) tetraamine 21 [12,13] (Scheme 2).
Using our general PyBOP-mediated amide coupling reaction meth-
odology, reaction of 21 with three benzoic acids (benzoic acid, 2-
hydroxybenzoic acid, and 2,5-dimethoxybenzoic acid), five phenyl-
acetic acids (phenylacetic acid, 2-hydroxyphenylacetic acid, 2-
methoxyphenylacetic acid, 4-methoxyphenylacetic acid and 2,5-
dimethoxyphenylacetic acid) and four 3-phenylpropanoic acids (3-
phenylpropanoic acid, 3-(2-hydroxyphenyl)propanoic acid, 3-(2,5-
dimethoxyphenyl)propanoic acid and 3-(3,4-dimethoxyphenyl)
propanoic acid) gave Boc protected analogues 22e33. Subsequent
removal of the Boc groups with TFA in CH2Cl2 gave tetraamine-
diamides 34e45 as TFA salts.
3. Biological results and discussion
3.1. In vitro antimalarial activity
The resultant library of polyamine analogues was evaluated for
the ability to inhibit the growth of P. falciparum (strain K1, IEF stage),
and in order to establish selectivity indices, the cytotoxicity of
compounds towards the rat skeletal myoblast cell line L6 were also
determined. Summaries of these assay results are presented in
Table 1. Of the spermine analogues evaluated, benzamides 4e6
(entries 1e3) were either less active or equipotent to our original
natural product lead compound [10] while 3-phenylpropanamides
7e10 (entries 4e7) were typically more active. Of particular note
was the potency (Pf IC50 6.1 nM) and selectivity (SI 16,230) of the 2,5-
dimethoxyphenylacetamide 9 (entry 6). Evaluation of analogues
bearing a longer PA3-8-3 [14] polyamine chain identified that Boc-
protected derivatives 15e17, whilst being modestly active towards
P. falciparum, exhibited markedly enhanced levels of cytotoxicity
(entries 8e10), while the corresponding de-Boc analogues 18e20
exhibited good to potent levels of antimalarial activity, with
negligible cytotoxicity (entries 11e13). A similar observation was
made for the PA3-12-3 [14] library of analogues, in that Boc
protected benzamides (22e24), phenylacetamides (25e29) and 3-
phenylpropanamides (30e33) exhibited only modest antimalarial
activity combined with enhanced cytotoxicity (entries 14e25).
Removal of the Boc protecting group led to no change in Pf activity or
selectivity for benzamide analogues 34e36 (entries 26e28), while
de-protected phenylacetamide and 3-phenylpropanamide ana-
logues 37e45 typically were as active or more potent towards Pf and
exhibited similar or less potent cytotoxicity (entries 29e37). The
pronounced anti-Pf activity of 2-hydroxy (8, 19, 38, 43) and 2,5-
dimethoxy (9, 20) phenylacetamide and phenylpropanamide ana-
logues is noteworthy.
Fig. 2. Benzamide and 3-phenylpropanamide analogues of spermine.

24
L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
Table 1
Polyamine analogues and their antimalarial and cytotoxic biological activities (mM).
Entry
No.
P. falc.a
L6b
SIc
1
2
3
4
5
6
7
8
4
5
6
7
8
0.45
1.9
0.93
0.10
0.015
0.0061
0.46
0.47
0.73
0.048
0.015
0.0013
0.012
0.16
0.50
0.18
0.26
0.17
0.46
0.21
0.16
0.24
0.13
0.18
0.066
0.16
0.38
89
83
75
91
86
99
73
8.6
16
1.9
74
55
61
8.3
93
1.8
8.2
10
2.7
4.7
2.2
4.0
3.6
2.3
2.5
6.9
2.5
2.2
200
44
81
910
5700
16,230
160
18
9
10
15
16
17
18
19
20
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
9
22
40
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
4933
42,300
5083
52
186
10
32
59
5.9
22
14
17
28
13
38
43
6.6
5.6
138
4880
269
95
121
95
0.39
0.16
22
0.0086
0.078
0.200
0.19
0.073
0.0095
0.11
42
21
19
23
6.9
62
6.5
57
6530
59
803
0.071
All data is the mean value from duplicate assays.
a
Plasmodium falciparum. IC50 (mM).
L6 rat skeletal myoblast cell line. IC50 (mM).
Selectivity index (SI) ¼ IC50 L6/IC50 Pf.
b
c
Scheme 2. Preparation of polyamine analogues 22e45. Reagents and conditions: (i)
carboxylic acid (2 equiv), PyBOP, DMF, Et3N, N2, 23 h (ii) CH2Cl2, TFA, N2, 2 h.
substituted phenylacetamide or 3-phenylpropanamide polyamine
analogues were found to be particularly potent antimalarials.
In vitro activity did not translate to in vivo efficacy however,
suggesting elements of poor pharmacokinetics are associated with
this current set of compounds. Further work is needed to identify
analogues that can exhibit in vivo activity e research towards this
goal is currently ongoing.
3.2. In vivo antimalarial evaluation
Three analogues, 2-hydroxyphenylacetamido-spermine 2, 2-
hydroxyphenylpropanamido-spermine 8 and phenylacetamido-
PA383 18 were selected for preliminary in vivo evaluation in P.
berghei infected mice. Preliminary ip acute toxicity of the three test
compounds was determined to be 150 mg/kg (2) and 100 mg/kg
(18) whereas 8 showed no toxicity up to the highest test dose of
150 mg/kg. Using a standard test protocol [15], repeated ip doses of
50 (mg/kg)/day (for 8) or 20 (mg/kg)/day (for 18) for four days failed
to demonstrate any antimalarial efficacy and no increase in mean
survival time was observed. Repeated 30 (mg/kg)/day ip dosing of 2
did lead to a 27.9% reduction in parasitaemia, but again, no increase
in mean survival time was observed.
5. Experimental
5.1. General experimental
Mass spectra were recorded on a Bruker micrOTOF Q II mass
spectrometer. Infrared spectra were run as dry films on an ATR
crystal and acquired with a Perkin Elmer Spectrum One Fourier
Transform infrared spectrometer with a Universal ATR Sampling
Accessory. Melting points were obtained on an Electrothermal
melting point apparatus and are uncorrected. 1H NMR (300.13 or
400.13 MHz) and 13C NMR (75.47 or 100.62 MHz) spectra were run
on a Bruker Avance 300 MHz or a Bruker DRX 400 MHz spec-
trometer. Chemical shifts are expressed in parts per million (ppm)
relative to TMS in CDCl3 1H NMR and to deuterated solvent in 1H
NMR (DMSO-d6: 2.50 ppm, CD3OD: 3.31 ppm) and to deuterated
solvent signals in 13C NMR (CDCl3: 77.16 ppm, DMSO-d6: 39.52 ppm,
CD3OD: 49.00 ppm). Complete assignment of 1H and 13C NMR
4. Conclusions
A series of diamido-polyamine derivatives have been identified
that exhibit potent in vitro activity against P. falciparum. In addi-
tion to a range of different ‘capping acids’, different lengths of
polyamine chains and the presence (or absence) of mid-chain ni-
trogen substitution were investigated for their effects on the
growth inhibition of P. falciparum. While mid-chain Boc derivatives
were typically found to have enhanced cytotoxicity, 2-hydroxy-

L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
25
resonances was based on interpretation of standard 2D NMR data.
0.62 mmol) and Et3N (228
mL, 1.65 mmol) afforded 6 as a clear
Pressurized (flash) column chromatography was performed on
Kieselgel 60 0.063e0.200 mesh (Merck) silica gel or C8/C18/CN/LH-
20 solid supports. Analytical thin layer chromatography (TLC) was
carried out on 0.2 mm thick plates of Kieselgel F254 (Merck).
Analytical reversed phase HPLC analyses were run on either a
Waters 600 HPLC photodiode array system or a Dionex UltiMate
3000 with diode array detection using a C8 column (Grace Platinum
colourless gum (123 mg, 59% yield). Rf (10% MeOH/CH2Cl2) 0.43; IR
nmax (ATR) 3374, 2951, 2839, 1672, 1494, 1175, 720 cmꢂ1 1H NMR
(DMSO-d6, 400 MHz) 8.61 (2H, br s, NH2-12), 8.40 (1H, t,
;
d
J ¼ 6.1 Hz, NH-8), 7.28 (1H, d, J ¼ 3.0 Hz, H-6), 7.09e7.03 (2H, m, H-3
and H-4), 3.83 (3H, s, OMe-16), 3.72 (3H, s, OMe-15), 3.35 (2H, td,
J ¼ 6.5, 6.1 Hz, H2-9), 2.94 (4H, br s, H2-11 and H2-13), 1.85 (2H, tt,
J ¼ 6.5, 6.5 Hz, H2-10), 1.64 (2H, br s, H2-14); 13C NMR (DMSO-d6,
3
m
m, 33 ꢁ 7 mm Rocket) eluting with a linear gradient of H2O
100 MHz) d 165.3 (C-7), 153.0 (C-5), 151.1 (C-2), 123.5 (C-1), 117.5 (C-
(þ0.05% TFA) to MeCN over 13.5 min at 2 mL/min with monitoring
at 278 nm. Reactions were heated by immersion in oil or by use of
DrySynÔ MULTI reaction block kit while the temperature was taken
from a thermometer touching the bottom of the pyrex bath. Poly-
amine 21 was prepared using literature methods [12,13].
4), 115.2 (C-6), 113.5 (C-3), 56.4 (C-16), 55.5 (C-15), 46.1 (C-13), 44.7
(C-11), 36.3 (C-9), 26.1 (C-10), 22.8 (C-14); (þ)-HRESIMS m/z
531.3179 [M þ H]þ (calcd for C28H43N4O6, 531.3177); Purity 99%
tR ¼ 5.27 min.
5.2.5. N1,N4-Bis(3-(3-phenylpropanamido)propyl)butane-1,4-
diaminium 2,2,2-trifluoroacetate (7)
5.2. Synthesis of diamides 4e10
Using general procedure A, 3-phenylpropanoic acid (120 mg,
0.80 mmol), spermine (81 mg, 0.40 mmol), PyBOP (437 mg,
5.2.1. General procedure A: amide bond formation
To a solution of carboxylic acid (2.05 equiv.), diamine (1 equiv.),
and PyBOP (2.05 equiv.) in DMF (1 mL) was added Et3N (3 equiv.).
The reaction mixture was allowed to stir under N2 at room tem-
perature for 23 h. The solution was dried in vacuo and the crude
reaction product purified by C8 reversed-phase column chroma-
tography (20e30% MeOH/H2O (þ0.05%TFA)) to afford the target
diamide as the bis-trifluoroacetate salt or by silica gel column
chromatography to afford the target diamide as the free base.
0.84 mmol) and Et3N (332
yellow gum (255 mg, 92% yield). Rf (10% MeOH/CH2Cl2) 0.44; IR nmax
(ATR) 3260, 3030, 2834, 1666, 1639, 1201, 1141, 839, 722 cmꢂ1 1H
NMR (DMSO-d6, 400 MHz) 8.64e8.58 (2H, m, NH2-14), 8.06 (1H, t,
mL, 2.40 mmol) afforded 7 as a pale
;
d
J ¼ 5.9 Hz, NH-10), 7.29e7.25 (2H, m, H-3, and H-5), 7.19e7.15 (3H,
m, H-2, H-4, and H-6), 3.11 (2H, td, J ¼ 6.7, 5.9 Hz, H2-11), 2.87 (2H,
br s, H2-15), 2.84e2.80 (4H, m, H2-7, and H2-13), 2.40 (2H, t,
J ¼ 8.1 Hz, H2-8), 1.69 (2H, tt, J ¼ 6.7 Hz, H2-12), 1.61 (2H, br s, H2-
16); 13C NMR (DMSO-d6, 100 MHz)
d 172.0 (C-9), 141.2 (C-1), 128.3
5.2.2. N1,N4-Bis(3-benzamidopropyl)butane-1,4-diaminium 2,2,2-
trifluoroacetate (4)
Using general procedure A, benzoic acid (100 mg, 0.82 mmol),
spermine (83 mg, 0.41 mmol), PyBOP (426 mg, 0.82 mmol) and Et3N
(C-2, C-6), 128.2 (C-3, and C-5), 126.0 (C-4), 46.1/46.0 (C-15), 44.6/
44.5 (C-13), 36.9/36.8 (C-8), 35.6/35.4 (C-11), 31.0 (C-7), 26.1 (C-12),
22.7 (C-16); (þ)-HRESIMS m/z 467.3371 [M þ H]þ (calcd for
C28H43N4O2, 467.3381); Purity 99% tR ¼ 4.81 min.
(340
Mp 150 ꢀC; Rf (20% MeOH/CH2Cl2) 0.22; IR nmax (ATR) 3289, 3069,
2851, 1668, 1638, 1130, 719 cmꢂ1 1H NMR (DMSO-d6, 400 MHz)
mL, 2.46 mmol) afforded 4 as a white solid (124 mg, 47% yield).
5.2.6. N1,N4-Bis(3-(3-(2-hydroxyphenyl)propanamido)propyl)
butane-1,4-diaminium 2,2,2-trifluoroacetate (8)
;
d
8.65 (1H, t, J ¼ 5.8 Hz, NH-8), 8.60 (2H, br s, NH2-12), 7.87e7.84
Using general procedure A, 3-(2-hydroxyphenyl)propanoic acid
(100 mg, 0.60 mmol), spermine (61 mg, 0.30 mmol), PyBOP
(344 mg, 0.66 mmol) and Et3N (500 mL, 3.61 mmol) afforded 8 as a
(2H, m, H-2 and H-6), 7.56e7.52 (1H, m, H-4), 7.49e7.45 (2H, m, H-3
and H-5), 3.34 (2H, td, J ¼ 6.5, 5.8 Hz, H2-9), 2.94 (4H, br s, H2-11 and
H2-13), 1.86 (2H, tt, J ¼ 6.5, 6.5 Hz, H2-10), 1.63 (2H, br s, H2-14); 13
C
clear colourless gum (183 mg, 84% yield). Rf (50% MeOH/CH2Cl2)
0.36; IR nmax (ATR) 3283, 3075, 2835, 1671, 1635, 1456, 1199, 1131,
NMR (DMSO-d6, 100 MHz)
d 166.6 (C-7), 134.2 (C-1), 131.3 (C-4),
128.3 (C-3 and C-5), 127.2 (C-2 and C-6), 46.1 (C-13), 44.8 (C-11),
36.3 (C-9), 26.1 (C-10), 22.7 (C-14); (þ)-HRESIMS m/z 411.2744
[M þ H]þ (calcd for C24H35N4O2, 411.2755); Purity 97% tR ¼ 5.91 min.
721 cmꢂ1; 1H NMR (DMSO-d6, 400 MHz)
d 9.40 (1H, br s, OH), 8.62
(2H, br s, NH2-14), 8.04 (1H, t, J ¼ 6.0 Hz, NH-10), 7.03 (1H, dd,
J ¼ 7.6, 1.6 Hz, H-6), 6.99 (1H, ddd, J ¼ 7.6, 7.6, 1.6 Hz, H-4), 6.78 (1H,
dd, J ¼ 7.6, 1.0 Hz, H-3), 6.69 (1H, ddd, J ¼ 7.6, 7.6, 1.0, H-5), 3.11 (2H,
td, J ¼ 6.6, 6.0 Hz, H2-11), 2.89 (2H, br s, H2-15), 2.83 (2H, br s, H2-
13), 2.74 (2H, t, J ¼ 7.7 Hz, H2-7), 2.36 (2H, t, J ¼ 7.7 Hz, H2-8), 1.70
(2H, tt, J ¼ 6.6, 6.6 Hz, H2-12), 1.62 (2H, br s, H2-16); 13C NMR
5.2.3. N1,N4-Bis(3-(2-hydroxybenzamido)propyl)butane-1,4-
diaminium 2,2,2-trifluoroacetate (5)
Using general procedure A, 2-hydroxybenzoic acid (100 mg,
0.72 mmol), spermine (73 mg, 0.36 mmol), PyBOP (396 mg,
(DMSO-d6, 100 MHz) d 172.6 (C-9), 155.1 (C-2), 129.6 (C-6), 127.3 (C-
0.76 mmol) and Et3N (105
colourless gum (68 mg, 28% yield). Rf (20% MeOH/CH2Cl2) 0.17; IR
nmax (ATR) 3347, 2989, 2844, 1674, 1638, 1596, 1201, 1133, 722 cmꢂ1
1H NMR (DMSO-d6, 400 MHz)
12.51 (1H, s, OH-2), 8.96 (1H, t,
m
L, 0.76 mmol) afforded 5 as a clear
1), 127.0 (C-4), 118.9 (C-5), 115.0 (C-3), 46.1 (C-15), 44.6 (C-13), 35.6
(C-11), 35.3 (C-8), 26.1 (C-12), 25.8 (C-7), 22.7 (C-16); (þ)-HRESIMS
m/z 499.3264 [M þ H]þ (calcd for C28H43N4O4, 499.3279); Purity
99% tR ¼ 4.01 min. The 1H and 13C data were in agreement with the
literature values [16].
;
d
J ¼ 5.9 Hz, NH-8), 8.67 (2H, br s, NH2-12), 7.84 (1H, dd, J ¼ 7.9,1.6 Hz,
H-6), 7.40 (1H, ddd, J ¼ 7.9, 7.9, 1.6 Hz, H-4), 6.92e6.86 (2H, m, H-3
and H-5), 3.37 (2H, td, J ¼ 6.6, 5.9 Hz, H2-9), 2.94 (4H, br s, H2-11 and
5.2.7. N1,N4-Bis(3-(3-(2,5-dimethoxyphenyl)propanamido)propyl)
butane-1,4-diaminium 2,2,2-trifluoroacetate (9)
Using general procedure A, 3-(2,5-dimethoxyphenyl)propanoic
acid (100 mg, 0.48 mmol), spermine (35 mg, 0.24 mmol), PyBOP
H2-13), 1.88 (2H, tt, J ¼ 6.6, 6.6 Hz, H2-10), 1.63 (2H, br s, H2-14); 13
C
NMR (DMSO-d6, 100 MHz)
d
169.2 (C-7), 159.9 (C-2), 133.7 (C-4),
127.8 (C-6), 118.6 (C-5), 117.4 (C-3), 115.3 (C-1), 46.1 (C-13), 44.7 (C-
11), 36.2 (C-9), 25.8 (C-10), 22.7 (C-14); (þ)-HRESIMS m/z 443.2642
(300 mg, 0.58 mmol) and Et3N (198 mL, 1.43 mmol) afforded 9 as a
[M
þ
H]þ (calcd for C24H35N4O4, 443.2653); Purity 99%
clear colourless gum (28 mg, 14% yield). Rf (20% MeOH/CH2Cl2)
0.44; IR nmax (ATR) 3279, 2949, 2836, 1673, 1500, 1224, 1200, 1026,
tR ¼ 5.18 min.
719 cmꢂ1; 1H NMR (DMSO-d6, 400 MHz)
d 8.63 (2H, br s, NH2-14),
5.2.4. N1,N4-Bis(3-(2,5-dimethoxybenzamido)propyl)butane-1,4-
diaminium 2,2,2-trifluoroacetate (6)
Using general procedure A, 2,5-dimethoxybenzoic acid (100 mg,
0.55 mmol), spermine (56 mg, 0.27 mmol), PyBOP (322 mg,
8.04 (1H, t, J ¼ 5.9 Hz, NH-10), 6.86e6.84 (1H, m, H-3), 6.74e6.71
(2H, m, H-4 and H-6), 3.72 (3H, s, OMe-17), 3.67 (3H, s, OMe-18),
3.11 (2H, td, J ¼ 6.6, 5.9 Hz, H2-11), 2.89 (2H, br s, H2-15), 2.84
(2H, br s, H2-13), 2.74 (2H, t, J ¼ 7.4 Hz, H2-7), 2.34 (2H, t, J ¼ 7.4 Hz,

26
L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
H2-8), 1.71 (2H, tt, J ¼ 6.6, 6.6 Hz, H2-12), 1.62 (2H, br s, H2-16); 13
C
5.3.3. Di-tert-butyl octane-1,8-diylbis((3-aminopropyl)carbamate)
(14)
NMR (DMSO-d6, 100 MHz)
d 172.1 (C-9), 153.0 (C-5), 151.2 (C-2),
130.1 (C-1), 115.8 (C-6), 111.5 (C-3), 111.1 (C-4), 55.7 (C-17), 55.3 (C-
18), 46.1 (C-15), 44.6 (C-13), 35.6 (C-11), 35.2 (C-8), 26.1 (C-12), 25.8
(C-7), 22.7 (C-16); (þ)-HRESIMS m/z 587.3787 [M þ H]þ (calcd for
To a solution of 13 (379 mg, 0.84 mmol) in dioxane/H2O (4:1,
30 mL) was added LiOH (141 mg, 3.36 mmol), 10% Pd/C (450 mg,
0.42 mmol), and 50% nickelealuminium alloy (790 mg, 6.73 mmol).
The reaction mixture was heated to 50 ꢀC and allowed to stir over-
night (21 h) under H2 atmosphere. After cooling to room tempera-
ture, a solution of 1% K2CO3 (50 mL) was added to the reaction
mixture and the product was extracted with CH2Cl2 (3 ꢁ 50 mL). The
organic fractions were combined, dried (MgSO4) and solvent
removed in vacuo to give the desired product 14 as a pale yellow oil
(272 mg, 71% yield). Rf (10% MeOH/CH2Cl2) 0.23; IR nmax (ATR) 3367,
2973, 2928, 2857,1683,1416,1364,1158, 771 cmꢂ1; 1H NMR (DMSO-
C
32H51N4O6, 587.3803); Purity 99% tR ¼ 5.55 min.
5.2.8. N1,N4-Bis(3-(3-(3,4-dimethoxyphenyl)propanamido)propyl)
butane-1,4-diaminium 2,2,2-trifluoroacetate (10)
Using general procedure A, 3-(3,4-dimethoxyphenyl)propanoic
acid (113 mg, 0.54 mmol), spermine (52 mg, 0.26 mmol), PyBOP
(268 mg, 0.51 mmol) and Et3N (198
pale yellow gum (150 mg, 72% yield). Rf (20% MeOH/CH2Cl2) 0.21; IR
nmax (ATR) 3358, 2944, 2840, 1672, 1515, 1136, 1024, 838, 720 cmꢂ1
1H NMR (DMSO-d6, 400 MHz)
8.56 (2H, br s, NH2-14), 8.04 (1H, t,
mL, 1.43 mmol) afforded 10 as a
;
d6, 400 MHz)
d
3.14 (2H, t, J ¼ 6.6 Hz, H2-3), 3.08 (2H, t, J ¼ 7.2 Hz, H2-
d
5), 2.48e2.46 (2H, m, H2-1), 1.53e1.48 (2H, m, H2-2), 1.44e1.43 (2H,
m, H2-6),1.38 (9H, s, 3H3-11),1.25 (2H, br m, H2-8),1.22e1.20 (2H, m,
J ¼ 5.9 Hz, NH-10), 6.83 (1H, d, J ¼ 8.2 Hz, H-5), 6.79 (1H, d,
J ¼ 1.9 Hz, H-2), 6.69 (1H, dd, J ¼ 8.2, 1.9 Hz, H-6), 3.72 (3H, s, OMe-
17), 3.70 (3H, s, OMe-18), 3.11 (2H, td, J ¼ 6.6, 5.9 Hz, H2-11), 2.87
(2H, br s, H2-15), 2.80 (2H, br s, H2-13), 2.75 (2H, t, J ¼ 7.7 Hz, H2-7),
2.37 (2H, t, J ¼ 7.7 Hz, H2-8), 1.69 (2H, tt, J ¼ 6.6 Hz, H2-12), 1.61 (2H,
H2-7); 13C NMR (DMSO-d6, 100 MHz)
d 154.7 (C-9), 78.0 (C-10), 46.3
(C-5), 44.2:43.8 (C-3), 39.1 (C-1), 32.5:31.8 (C-2), 28.7 (C-8), 28.1 (C-
11), 27.9 (C-6), 26.2 (C-7); (þ)-HRESIMS m/z 459.3891 [M þ H]þ
(calcd for C24H51N4O4, 459.3905).
br s, H2-16); 13C NMR (DMSO-d6, 100 MHz)
d 172.1 (C-9), 148.6 (C-
3), 147.1 (C-4), 133.7 (C-1), 119.9 (C-6), 112.1 (C-2), 111.9 (C-5), 55.5
(C-18), 55.4 (C-17), 46.1 (C-15), 44.6 (C-13), 37.2 (C-8), 35.5 (C-11),
30.7 (C-7), 26.1 (C-12), 22.7 (C-16); (þ)-HRESIMS m/z 587.3771
5.3.4. Di-tert-butyl octane-1,8-diylbis((3-(2-phenylacetamido)
propyl)carbamate) (15)
Using general procedure A, reaction of phenylacetic acid (59 mg,
0.44 mmol), 14 (100 mg, 0.22 mmol), PyBOP (284 mg, 0.55 mmol)
[M
þ
H]þ (calcd for C32H51N4O6, 587.3803); Purity 99%
tR ¼ 4.41 min.
and Et3N (181 mL, 1.31 mmol) yielded a crude product that was
purified by silica gel column chromatography (2% MeOH/CH2Cl2) to
afford 15 as clear colourless gum (114 mg, 75% yield). Rf (10% MeOH/
CH2Cl2) 0.77; IR nmax (ATR) 3292, 2974, 2929, 2857, 1687, 1647, 415,
5.3. Synthesis of diamides 15e17
5.3.1. 3,30-(Octane-1,8-diylbis(azanediyl))dipropanenitrile (12)
To a solution of 1,8-diaminooctane (11) (100 mg, 0.69 mmol) in
EtOH (2 mL) was added acrylonitrile (92 mL, 1.39 mmol). The re-
action mixture was purged with N2 and heated to reflux for 3 h. The
crude product was concentrated in vacuo and purified by Et3N-
deactivated silica gel column chromatography (10% MeOH/CH2Cl2)
and reversed-phase cyanopropyl column chromatography (25%
MeOH/H2O (TFA)) to give 12 as a white solid (117 mg, 38% yield). Mp
143 ꢀC; Rf (10% MeOH/CH2Cl2) 0.85; IR nmax (ATR) 3091, 2940, 2863,
2258, 1663, 1462, 1416, 1195, 1162, 1122, 719 cmꢂ1; 1H NMR (DMSO-
1154, 721, 696 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d 7.35e7.26 (5H, m,
H-2, H-3, H-4, H-5 and H-6), 6.70 (1H, br s, NH-9), 3.55 (2H, s, H2-7),
3.18e3.17 (4H, m, H2-10 and H2-12), 3.06 (2H, t, J ¼ 7.0 Hz, H2-14),
1.61e1.67 (2H, m, H2-11), 1.49e1.44 (2H, m, H2-15), 1.41 (9H, s, 3H3-
20), 1.26e1.22 (4H, m, H2-16 and H2-17); 13C NMR (CDCl3, 100 MHz)
d
171.2 (C-8), 156.6 (C-18), 135.4 (C-1), 129.5 (C-2 and C-6), 128.9 (C-
3 and C-5), 127.2 (C-4), 79.6 (C-19), 47.1 (C-14), 44.2 (C-7), 43.4 (C-
12), 36.0 (C-10), 29.5 (C-17), 28.5 (C-15 and C-20), 27.8 (C-11), 26.9
(C-16); (þ)-HRESIMS m/z 695.4725 [M þ H]þ (calcd for C40H63N4O6,
695.4742); Purity 95% tR ¼ 7.44 min.
d6, 400 MHz)
2.95e2.90 (4H, m, H2-3 and H2-5), 1.59e1.55 (2H, m, H2-6), 1.27
(4H, br m, H2-7 and H2-8); 13C NMR (DMSO-d6, 100 MHz)
117.8 (C-
d
9.02 (1H, br s, NH-4), 3.26 (2H, t, J ¼ 7.0 Hz, H2-2),
5.3.5. Di-tert-butyl octane-1,8-diylbis((3-(2-(2-hydroxyphenyl)
acetamido)propyl) carbamate) (16)
d
1), 46.7 (C-5), 42.0 (C-2), 28.2 (C-8), 25.8 (C-7), 25.3 (C-6), 14.4 (C-
3); (þ)-HRESIMS m/z 251.2236 [M þ H]þ (calcd for C14H27N4,
251.2230).
Using general procedure A, reaction of 2-hydroxyphenylacetic
acid (40 mg, 0.26 mmol), 14 (60 mg, 0.13 mmol), PyBOP (170 mg,
0.33 mmol) and Et3N (109 mL, 0.78 mmol) yielded a crude product
that was purified by silica gel column chromatography (2% MeOH/
CH2Cl2) to afford 16 as a yellow gum (52 mg, 55% yield). Rf (10%
MeOH/CH2Cl2) 0.49; IR nmax (ATR) 3287, 2973, 2930, 1689, 1651,
5.3.2. Di-tert-butyl octane-1,8-diylbis((2-cyanoethyl)carbamate)
(13)
To a solution of 12 (190 mg, 0.76 mmol) and di-tert-butyl
dicarbonate (414 mg, 1.90 mmol) in CH2Cl2 (10 mL) was added
1420, 1159, 753 cmꢂ1 1H NMR (CDCl3, 400 MHz)
; d 10.16 (1H, br s,
OH), 7.53 (1H, br s, NH-9), 7.16 (1H, ddd, J ¼ 7.5, 7.5,1.7 Hz, H-4), 7.06
(1H, br d, J ¼ 7.5 Hz, H-6), 6.95 (1H, dd, J ¼ 7.5, 1.1 Hz, H-3), 6.81 (1H,
ddd, J ¼ 7.5, 1.1 Hz, H-5), 3.56 (2H, s, H2-7), 3.24e3.17 (4H, m, H2-10
and H2-12), 3.09 (2H, t, J ¼ 7.3 Hz, H2-14), 1.63 (2H, br s, H2-11),
1.47e1.41 (11H, br m, H2-15 and 3H3-20), 1.27e1.24 (4H, br m, H2-
Et3N (420 mL, 3.04 mmol). The reaction mixture was allowed to
stir under N2 at room temperature for 22.5 h. After this time, H2O
(50 mL) was added to the reaction mixture, the organic phase
separated and dried (MgSO4) and solvent removed in vacuo to
give the desired product 13 as a light yellow oil (321 mg, 94%
yield) which was used in the following step without further pu-
rification. Rf (10% MeOH/CH2Cl2) 0.79; IR nmax (ATR) 2976, 2930,
16 and H2-17); 13C NMR (CDCl3, 100 MHz)
d 173.4 (C-8), 156.9 (C-
18), 156.4 (C-2), 130.7 (C-6), 129.0 (C-4), 122.2 (C-1), 120.2 (C-5),
118.0 (C-3), 80.1 (C-19), 47.2 (C-14), 43.4 (C-12), 41.3 (C-7), 36.1 (C-
10), 29.4 (C-17), 28.5 (C-15 and C-20), 27.5 (C-11), 26.9 (C-16);
(þ)-HRESIMS m/z 727.4622 [M þ H]þ (calcd for C40H63N4O8,
727.4640).
2858, 2249, 1686, 1413, 1366, 1154, 773 cmꢂ1
300 MHz)
;
1H NMR (CDCl3,
3.46 (2H, t, J ¼ 6.7 Hz, H2-3), 3.25 (2H, t, J ¼ 7.2 Hz,
d
H2-5), 2.62 (2H, br s, H2-2), 1.54e1.44 (2H, m, H2-6), 1.49 (9H, s,
3H3-11), 1.30e1.27 (4H, m, H2-7 and H2-8); 13C NMR (CDCl3,
75 MHz)
d
155.4:154.6 (C-9), 118.5:117.9 (C-1), 80.3 (C-10),
5.3.6. Di-tert-butyl octane-1,8-diylbis((3-(2-(2,5-dimethoxyphenyl)
acetamido)propyl)carbamate) (17)
Using general procedure A, reaction of 2,5-dimethoxyphenyl
acetic acid (86 mg, 0.44 mmol), 14 (100 mg, 0.22 mmol), PyBOP
48.7:47.9 (C-5), 44.0:43.6 (C-3), 29.4 (C-8), 28.9 (C-6), 28.5 (C-11),
26.8 (C-7), 17.7:17.1 (C-2); (þ)-HRESIMS m/z 473.3089 [M þ Na]þ
(calcd for C24H42N4NaO4, 473.3098).

L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
27
(284 mg, 0.55 mmol) and Et3N (181
m
L, 1.31 mmol) yielded a crude
5.4.4. N1,N8-Bis(3-(2-(2,5-dimethoxyphenyl)acetamido)propyl)
octane-1,8-diaminium 2,2,2-trifluoroacetate (20)
Using general procedure B, reaction of 17 (53 mg, 0.065 mmol) in
CH2Cl2 (2 mL) with TFA (200 L) and subsequent purification by C8
product that was purified by silica gel column chromatography (2%
MeOH/CH2Cl2) to afford 17 as a clear colourless gum (114 mg, 64%
yield). Rf (10% MeOH/CH2Cl2) 0.59; IR nmax (ATR) 3310, 2973, 2930,
m
2856, 1685, 1501, 1225, 1157, 1048, 715 cmꢂ1
;
1H NMR (CDCl3,
reversed-phase column chromatography (50% MeOH/H2O (TFA))
afforded 20 as a clear colourless gum (48 mg, 88% yield). Rf (20%
MeOH/CH2Cl2) 0.55; IR nmax (ATR) 2940, 2839, 1775, 1645, 1502,
400 MHz) d 6.83e6.76 (3H, m, H-3, H-4 and H-6), 6.67 (1H, br s, NH-
9), 3.81 (3H, s, OMe-22), 3.76 (3H, s, OMe-21), 3.52 (2H, s, H2-7),
3.15 (4H, br s, H2-10 and H2-12), 3.05 (2H, br s, H2-14), 1.59 (2H, br s,
H2-11), 1.49e1.44 (2H, m, H2-15), 1.41 (9H, s, 3H3-20), 1.26e1.21
1135,1045, 798, 704 cmꢂ1; 1H NMR (DMSO-d6, 400 MHz)
d 8.51 (2H,
br s, NH2-13), 7.99 (1H, t, J ¼ 6.0 Hz, NH-9), 6.88e6.86 (1H, m, H-3),
6.78e6.76 (2H, m, H-4 and H-6), 3.70 (3H, s, OMe-19), 3.68 (3H, s,
OMe-18), 3.37 (2H, s, H2-7), 3.13 (2H, td, J ¼ 6.7, 6.0 Hz, H2-10), 2.89e
2.80 (4H, m, H2-12 and H2-14), 1.73 (2H, tt, J ¼ 6.7, 6.7 Hz, H2-11),
1.55e1.50 (2H, m, J ¼ 7.3, 7.3 Hz, H2-15), 1.25 (4H, m, H2-16 and H2-
(4H, m, H2-16 and H2-17); 13C NMR (CDCl3, 100 MHz)
d 171.2 (C-8),
156.2 (C-18), 153.7 (C-5), 151.6 (C-2), 124.9 (C-1), 117.0 (C-6), 113.2
(C-4), 111.7 (C-3), 79.3 (C-19), 56.1 (C-22), 55.7 (C-21), 47.1 (C-14),
44.7:43.4 (C-12), 39.0 (C-7), 37.3:36.0 (C-10), 29.4 (C-17), 28.6 (C-
15), 28.4 (C-20), 28.0 (C-11), 26.9 (C-16); (þ)-HRESIMS m/z
815.5179 [M þ H]þ (calcd for C44H71N4O10, 815.5165); Purity 95%
tR ¼ 7.56 min.
17); 13C NMR (DMSO-d6, 100 MHz)
d 170.6 (C-8), 152.9 (C-5), 151.4
(C-2), 125.4 (C-1), 117.1 (C-6), 111.8 (C-4), 111.6 (C-3), 55.9 (C-19),
55.3 (C-18), 46.7 (C-14), 44.5 (C-12), 36.8 (C-7), 35.7 (C-10), 28.3 (C-
17), 26.1 (C-11), 25.8 (C-16), 25.4 (C-15); (þ)-HRESIMS m/z 615.4089
[M þ H]þ (calcd for C34H55N4O6, 615.4116); Purity 99% tR ¼ 5.74 min.
5.4. Synthesis of diamides 18e20
5.4.1. General procedure B: removal of Boc protecting group
5.5. Synthesis of diamides 22e33
A solution of tert-butyl-carbamate derivative in CH2Cl2 (2 mL)
and TFA (0.2 mL) was stirred at room temperature under N2 for 2 h,
then dried in vacuo to afford the deprotected analogue. In some
cases the product required no further purification, while in other
cases, purification was achieved by C18 reversed-phase column
chromatography eluting with 0e50% MeOH/H2O (þ0.05% TFA).
5.5.1. Di-tert-butyl dodecane-1,12-diylbis(3-
benzamidopropylcarbamate) (22)
Using general procedure A, reaction of benzoic acid (31 mg,
0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP (131 mg,
0.25 mmol), andEt3N (54 mL, 0.39 mmol)yielded a crude product that
was purified bysilica gel column chromatography (1% MeOH/CH2Cl2)
to afford 22 (39 mg, 54% yield) as a colourless oil. Rf (5% MeOH/
CH2Cl2) 0.33; IR nmax (ATR) 3326, 2926, 2854,1666, 1644,1538, 1365,
5.4.2. N1,N8-Bis(3-(2-phenylacetamido)propyl)octane-1,8-
diaminium 2,2,2-trifluoroacetate (18)
Using general procedure B, reaction of 15 (35.0 mg, 0.05 mmol)
1302,1156, 731 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d 7.92e7.86 (3H, m,
in CH2Cl2 (2 mL) with TFA (200
m
L) and subsequent purification by
H-2, H-4andNH-8), 7.49e7.40(3H, m, H-3, H-5andH-6), 3.43(2H, dt,
J ¼ 5.9, 5.8 Hz, H2-9), 3.37e3.33 (2H, m, H2-11), 3.14 (2H, t, J ¼ 7.3 Hz,
H2-13),1.77e1.70 (2H, m, H2-10),1.55e1.47 (2H, m, H2-14),1.47 (9H, s,
3H3-21), 1.27 (8H, br s, H2-15, H2-16, H2-17 and H2-18); 13C NMR
C8 reversed-phase column chromatography (50% MeOH/H2O
(TFA)) afforded 18 as a clear pale yellow gum (40.0 mg, quanti-
tative yield). Rf (20% MeOH/CH2Cl2) 0.83; IR nmax (ATR) 3285, 2938,
2860, 1673, 1556, 1201, 1178, 1132, 721 cmꢂ1
;
1H NMR (DMSO-d6,
(CDCl3, 100 MHz) d 167.2 (C-7), 157.0 (C-19), 134.8 (C-1), 131.3 (C-6),
400 MHz)
d
8.52 (2H, br s, NH2-13), 8.27 (1H, t, J ¼ 5.9 Hz, NH-9),
128.6, (C-3 and C-5),127.2 (C-2 and C-4), 79.9 (C-20), 47.1 (C-13), 43.3
(C-11), 35.9 (C-9), 29.7, 29.7, 29.5 (C-16, C-17 and C-18), 28.7 (C-14),
28.6 (C-21), 27.8 (C-10), 27.0 (C-15); (þ)-HRESIMS m/z 723.5039
[M þ H]þ (calcd for C42H67N4O6, 723.5055); Purity 99% tR ¼ 7.96 min.
7.31e7.19 (5H, m, H-2, H-3, H-4, H-5 and H-6), 3.41 (2H, s, H2-7),
3.12 (2H, td, J ¼ 6.7, 5.9 Hz, H2-10), 2.87e2.79 (4H, m, H2-12 and
H2-14), 1.72 (2H, tt, J ¼ 6.7, 6.7 Hz, H2-11), 1.53 (2H, br tt, J ¼ 6.9,
6.9 Hz, H2-15), 1.26 (4H, br s, H2-16 and H2-17); 13C NMR (DMSO-
d6, 100 MHz)
d
170.7 (C-8), 136.3 (C-1), 128.9 (C-2 and C-6), 128.2
5.5.2. Di-tert-butyl dodecane-1,12-diylbis(3-(2-hydoxybenzamido)
propylcarbamate) (23)
Using general procedure A, reaction of 2-hydroxybenzoic acid
(35 mg, 0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP (131 mg,
(C-3 and C-5), 126.4 (C-4), 46.7 (C-14), 44.5 (C-12), 42.3 (C-7), 35.8
(C-10), 28.3 (C-17), 26.0 (C-11), 25.8 (C-16), 25.4 (C-15);
(þ)-HRESIMS m/z 495.3696 [M þ H]þ (calcd for C30H47N4O2,
495.3694).
0.25 mmol), and Et3N (54 mL, 0.39 mmol) yielded a crude product
that was purified by silica gel column chromatography (2% MeOH/
CH2Cl2) to afford 23 (25 mg, 34% yield) as a colourless oil. Rf (5%
MeOH/CH2Cl2) 0.60; IR nmax (ATR) 3331, 2925, 2854,1665,1643,1541,
5.4.3. N1,N8-Bis(3-(2-(2-hydroxyphenyl)acetamido)propyl)octane-
1,8-diaminium 2,2,2-trifluoroacetate (19)
Using general procedure B, reaction of 16 (22 mg, 0.03 mmol)
1479, 1303, 1232, 1157, 754 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d 12.74
in CH2Cl2 (2 mL) with TFA (200
m
L) and subsequent purification by
(1H, br s, OH-22), 8.36 (1H, br s, NH-8), 7.64 (1H, br d, J ¼ 7.8 Hz, H-6),
7.37 (1H, ddd, J ¼ 8.3, 7.8, 1.4 Hz, H-4), 6.96 (1H, dd, J ¼ 8.3,1.4 Hz, H-
3), 6.87 (1H, ddd, J ¼ 8.3, 7.8, 1.4 Hz, H-5), 3.45e3.39 (2H, m, H2-9),
3.36 (2H, t, J ¼ 5.7 Hz, H2-11), 3.15 (2H, t, J ¼ 7.4 Hz, H2-13),1.77e1.70
(2H, m, H2-10), 1.57e1.45 (2H, m, H2-14), 1.49 (9H, s, 3H3-21), 1.28
(8H, br s, H2-15, H2-16, H2-17 and H2-18); 13C NMR (CDCl3,100 MHz)
C8 reversed-phase column chromatography (50% MeOH/H2O
(TFA)) afforded 19 as a clear pale yellow gum (21 mg, 92% yield). Rf
(20% MeOH/CH2Cl2) 0.62; IR nmax (ATR) 3326, 2943, 2863, 1779,
1672, 1459, 1137, 705 cmꢂ1 1H NMR (DMSO-d6, 400 MHz)
; d 9.72
(1H, br s, OH), 8.50 (2H, br s, NH2-13), 8.14 (1H, t, J ¼ 6.0 Hz, NH-
9), 7.08e7.03 (2H, m, H-4 and H-6), 6.80 (1H, d, J ¼ 7.6 Hz, H-3),
6.72 (1H, ddd, J ¼ 7.4, 7.4, 0.6 Hz, H-5), 3.39 (2H, s, H2-7), 3.14 (2H,
td, J ¼ 6.7, 6.0 Hz, H2-10), 2.91e2.80 (4H, m, H2-12 and H2-14), 1.73
(2H, tt, J ¼ 6.7, 6.7 Hz, H2-11), 1.53 (2H, br tt, J ¼ 6.7, 6.7 Hz, H2-15),
1.25 (4H, br s, H2-16 and H2-17); 13C NMR (DMSO-d6, 100 MHz)
d
170.1 (C-7), 161.8 (C-2), 157.3 (C-19), 133.9 (C-4), 126.2 (C-6), 118.8
(C-5), 118.4 (C-3), 114.8 (C-1), 80.2 (C-20), 47.3 (C-13), 43.2 (C-11),
35.2 (C-9), 29.7, 29.7, 29.5 (C-16, C-17 and C-18), 28.7 (C-14), 28.6 (C-
21), 27.7 (C-10), 27.0 (C-15); (þ)-HRESIMS m/z 777.4746 [M þ Na]þ
(calcd for C42H66N4NaO8, 777.4773); Purity 99% tR ¼ 8.10 min.
d
171.6 (C-8), 155.5 (C-2), 130.7 (C-6), 127.7 (C-4), 122.6 (C-1), 118.9
(C-5), 115.2 (C-3), 46.8 (C-14), 44.5 (C-12), 37.2 (C-7), 35.8 (C-10),
28.3 (C-17), 26.0 (C-11), 25.8 (C-16), 25.4 (C-15); (þ)-HRESIMS m/z
527.3585 [M þ H]þ (calcd for C30H47N4O4, 527.3592); Purity 95%
tR ¼ 4.93 min.
5.5.3. Di-tert-butyl dodecane-1,12-diylbis(3-(2,5-
dimethoxybenzamido)propylcarbamate) (24)
Using general procedure A, reaction of 2,5-dimethoxybenzoic
acid (46 mg, 0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP

28
L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
(131 mg, 0.25 mmol), and Et3N (54
m
L, 0.39 mmol) yielded a crude
(2% MeOH/CH2Cl2) to afford 27 (42 mg, 53% yield) as a colourless
cloudy oil. Rf (5% MeOH/CH2Cl2) 0.36; IR nmax (ATR) 3302, 2926,
2854, 1674, 1653, 1465, 1365, 1245, 1155, 732 cmꢂ1 1H NMR
(CDCl3, 400 MHz) 7.26e7.22 (2H, m, H-4 and H-6), 6.95e6.88
product that was purified by silica gel column chromatography (2%
MeOH/CH2Cl2) to afford 24 (55 mg, 65% yield) as a colourless oil. Rf
(5% MeOH/CH2Cl2) 0.32; IR nmax (ATR) 3365, 2926, 2854, 1683, 1651,
;
d
1493, 1154, 1044, 731 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d
8.61 (1H,
(2H, m, H-3 and H-5), 6.63 (1H, br s, NH-9), 3.85 (3H, s, OMe-23),
3.55 (2H, s, H2-7), 3.19e3.11 (4H, m, H2-10 and H2-12), 3.08e3.02
(2H, m, H2-14), 1.63e1.56 (2H, m, H2-11), 1.48e1.41 (2H, m, H2-15),
1.41 (9H, s, 3H3-22), 1.25 (6H, br s, H2-17, H2-18 and H2-19), 1.24e
br s, NH-8), 7.76 (1H, d, J ¼ 3.2 Hz, H-6), 6.98 (1H, dd, J ¼ 8.9, 3.2 Hz,
H-4), 6.90 (1H, d, J ¼ 8.9 Hz, H-3), 3.96 (3H, s, OMe-22), 3.82 (3H, s,
OMe-23), 3.48e3.40 (2H, m, H2-9), 3.33e3.25 (2H, m, H2-11), 3.19e
3.11 (2H, m, H2-13), 1.84e1.75 (2H, m, H2-10), 1.55e1.47 (2H, m, H2-
14), 1.46 (9H, s, 3H3-21), 1.26 (8H, br s, H2-15, H2-16, H2-17 and H2-
1.18 (2H, m, H2-16); 13C NMR (CDCl3, 100 MHz)
d 171.4 (C-8), 157.4
(C-2), 156.3 (C-20), 131.3 (C-6), 128.6 (C-4), 124.0 (C-1), 120.9 (C-5),
110.7 (C-3), 79.3 (C-21), 55.3 (C-23), 47.1 (C-14), 43.5 (C-12), 38.8
(C-7), 36.1 (C-10), 29.7, 29.7, 29.5 (C-17, C-18 and C-19), 28.7 (C-
15), 28.5 (C-22), 28.0 (C-11), 27.0 (C-16); (þ)-HRESIMS m/z
811.5590 [M þ H]þ (calcd for C46H75N4O8, 811.5579); Purity 99%
tR ¼ 8.05 min.
18); 13C NMR (CDCl3, 100 MHz)
d 165.2 (C-7), 156.3 (C-19), 153.8 (C-
5), 152.2 (C-2), 122.4 (C-1), 119.2 (C-4), 115.6 (C-6), 112.9 (C-3), 79.2
(C-20), 56.4 (C-22), 55.9 (C-23), 47.2 (C-13), 43.9 (C-11), 36.6 (C-9),
29.7, 29.7, 29.5 (C-16, C-17 and C-18), 28.7 (C-14), 28.6 (C-21), 28.2
(C-10), 27.0 (C-15); (þ)-HRESIMS m/z 843.5503 [M þ H]þ (calcd for
C
46H75N4O10, 843.5478); Purity 97% tR ¼ 8.19 min.
5.5.7. Di-tert-butyl dodecane-1,12-diylbis(3-(2-(4-methoxyphenyl)
acetamido)propylcarbamate) (28)
Using general procedure A, reaction of 4-methoxyphenylacetic
acid (42 mg, 0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP
5.5.4. Di-tert-butyl dodecane-1,12-diylbis(3-(2-phenylacetamido)
propylcarbamate) (25)
Using general procedure A, reaction of phenylacetic acid (31 mg,
0.23 mmol), 21 [12,13] (53 mg, 0.10 mmol), PyBOP (118 mg,
(131 mg, 0.25 mmol), and Et3N (54 mL, 0.39 mmol) yielded a crude
0.23 mmol), and Et3N (58
m
L, 0.41 mmol) yielded a crude product
product that was purified by silica gel column chromatography (2%
MeOH/CH2Cl2) to afford 28 (45 mg, 52% yield) as a colourless cloudy
oil. Rf (5% MeOH/CH2Cl2) 0.31; IR nmax (ATR) 3306, 2927, 2854, 1652,
that was purified by silica gel column chromatography (1.5% MeOH/
CH2Cl2) to afford 25 (27 mg, 35% yield) as a cloudy colourless oil. Rf
(5% MeOH/CH2Cl2) 0.33; IR nmax (ATR) 3298, 2925, 2854,1548,1365,
1511, 1418, 1365, 1245, 1155, 730 cmꢂ1 1H NMR (CDCl3, 400 MHz)
;
1154, 726 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d
7.35e7.27 (5H, m, H-2,
d
7.20 (2H, d, J ¼ 7.8 Hz, H-2 and H-6), 6.86 (2H, d, J ¼ 8.6 Hz, H-3
H-3, H-4, H-5 and H-6), 6.72 (1H, br s, NH-9), 3.55 (2H, s, H2-7),
3.22e3.14 (4H, m, H2-10 and H2-12), 3.06 (2H, t, J ¼ 7.1, 7.1 Hz, H2-
14), 1.63e1.57 (2H, m, H2-11), 1.49e1.41 (2H, m, H2-15), 1.41 (9H, s,
3H3-22), 1.27e1.19 (2H, m, H2-16), 1.20 (6H, br s, H2-17, H2-18 and
and H-5), 6.68 (1H, br s, NH-9), 3.79 (3H, s, OMe-23), 3.49 (2H, s, H2-
7), 3.21e3.13 (4H, m, H2-10 and H2-12), 3.06 (2H, t, J ¼ 6.6 Hz, H2-
14), 1.63e1.56 (2H, m, H2-11), 1.49e1.44 (2H, m, H2-15), 1.41 (9H, s,
3H3-22), 1.25 (8H, br s, H2-16, H2-17, H2-18 and H2-19); 13C NMR
H2-19); 13C NMR (CDCl3, 100 MHz)
d
171.2 (C-8), 156.4 (C-20), 135.3
(CDCl3, 100 MHz) d 171.6 (C-8), 158.8 (C-4), 156.5 (C-20), 130.6 (C-2
(C-1), 129.5 (C-2 and C-6), 128.9 (C-3 and C-5), 127.1 (C-4), 79.6 (C-
21), 47.1 (C-14), 44.0 (C-7), 43.3 (C-12), 35.9 (C-10), 29.7, 29.6, 29.5
(C-17, C-18 and C-19), 28.5 (C-22), 28.5 (C-15), 27.8 (C-11), 27.0 (C-
16); (þ)-HRESIMS m/z 751.5356 [M þ H]þ (calcd for C44H71N4O6,
751.5368); Purity 97% tR ¼ 7.94 min.
and C-6), 127.5 (C-1), 114.3 (C-3 and C-5), 79.5 (C-21), 47.1 (C-14),
43.4 (C-12), 43.2 (C-7), 35.9 (C-10), 29.7, 29.7, 29.5 (C-17, C-18 and
C-19), 28.6 (C-15), 28.5 (C-22), 27.8 (C-11), 27.0 (C-16); (þ)-HRE-
SIMS m/z 811.5571 [M þ H]þ (calcd for C46H75N4O8, 811.5579);
Purity 98% tR ¼ 7.94 min.
5.5.5. Di-tert-butyl dodecane-1,12-diylbis(3-(2-(2-hydroxyphenyl)
acetamido)propylcarbamate) (26)
5.5.8. Di-tert-butyl dodecane-1,12-diylbis(3-(2-(2,5-
dimethoxyphenyl)acetamido)propylcarbamate) (29)
Using general procedure A, reaction of 2-hydroxyphenylacetic
acid (34 mg, 0.22 mmol), 21 [12,13] (52 mg, 0.10 mmol), PyBOP
Using general procedure A, reaction of 2,5-dimethoxyphenyl
acetic acid (42 mg, 0.21 mmol), 21 [12,13] (50 mg, 0.10 mmol),
(116 mg, 0.22 mmol), and Et3N (56
mL, 0.40 mmol) yielded a crude
PyBOP (111 mg, 0.21 mmol), and Et3N (54 mL, 0.39 mmol) yielded a
product that was purified by silica gel column chromatography (2%
MeOH/CH2Cl2) to afford 26 (17 mg, 21% yield) as a pale yellow
cloudy oil. Rf (5% MeOH/CH2Cl2) 0.31; IR nmax (ATR) 3287, 2928,
crude product that was purified by silica gel column chromatog-
raphy (2% MeOH/CH2Cl2) to afford 29 (47 mg, 56% yield) as a col-
ourless cloudy oil. Rf (5% MeOH/CH2Cl2) 0.38; IR nmax (ATR) 3309,
2854, 1685, 1647, 1456, 1418, 1147, 752 cmꢂ1
;
1H NMR (CDCl3,
2926, 2854, 1675, 1652, 1417, 1224, 1156, 1048, 715 cmꢂ1 1H NMR
;
400 MHz)
d
10.18 (1H, br s, OH-2), 7.53 (1H, br s, NH-9), 7.17 (1H,
(CDCl3, 400 MHz)
d
6.83 (1H, d, J ¼ 2.7 Hz, H-6), 6.79 (1H, d,
ddd, J ¼ 8.0, 7.8, 1.3 Hz, H-4), 7.06 (1H, d, J ¼ 7.4 Hz, H-6), 6.96 (1H,
dd, J ¼ 8.0, 1.1 Hz, H-3), 6.82 (1H, ddd, J ¼ 7.8, 7.4, 1.1 Hz, H-5), 3.57
(2H, s, H2-7), 3.27e3.19 (4H, m, H2-10 and H2-12), 3.09 (2H, t,
J ¼ 7.4 Hz, H2-14), 1.66e1.60 (2H, m, H2-11), 1.53e1.47 (2H, m, H2-
15), 1.46 (9H, s, 3H3-22), 1.26 (8H, br s, H2-16, H2-17, H2-18 and H2-
J ¼ 8.8 Hz, H-3), 6.77 (1H, dd, J ¼ 8.8, 2.7 Hz, H-4), 6.66 (1H, br s, NH-
9), 3.81 (3H, s, OMe-24), 3.76 (3H, s, OMe-23), 3.52 (2H, s, H2-7),
3.18e3.13 (4H, m, H2-10 and H2-12), 3.09e3.02 (2H, m, H2-14),
1.63e1.56 (2H, m, H2-11), 1.47e1.43 (2H, m, H2-15), 1.41 (9H, s, 3H3-
22), 1.25 (8H, br s, H2-16, H2-17, H2-18 and H2-19); 13C NMR (CDCl3,
19); 13C NMR (CDCl3, 100 MHz)
d
173.5 (C-8), 157.0 (C-20), 156.6 (C-
100 MHz) d 171.2 (C-8), 156.2 (C-20), 153.8 (C-5), 151.6 (C-2), 125.0
2), 130.7 (C-6), 129.1 (C-4), 122.3 (C-1), 120.3 (C-5), 118.2 (C-3), 80.2
(C-21), 47.3 (C-14), 43.3 (C-12), 41.5 (C-7), 36.1 (C-10), 29.7, 29.7,
29.5 (C-17, C-18 and C-19), 28.6 (C-22 and C-16), 27.5 (C-11), 27.0 (C-
15); (þ)-HRESIMS m/z 783.5258 [M þ H]þ (calcd for C44H71N4O8,
783.5266); Purity 96% tR ¼ 7.60 min.
(C-1), 117.1 (C-6), 113.2 (C-4), 111.8 (C-3), 79.3 (C-21), 56.1 (C-24),
55.8 (C-23), 47.2 (C-14), 43.5 (C-12), 38.0 (C-7), 36.1 (C-10), 29.7,
29.7, 29.5 (C-17, C-18 and C-19), 28.7 (C-15), 28.5 (C-22), 28.0 (C-11),
27.0 (C-16); (þ)-HRESIMS m/z 871.5760 [M þ H]þ (calcd for
C
48H79N4O10, 871.5791); Purity 96% tR ¼ 8.05 min.
5.5.6. Di-tert-butyl dodecane-1,12-diylbis(3-(2-(2-methoxyphenyl)
acetamido)propylcarbamate) (27)
5.5.9. Di-tert-butyl dodecane-1,12-diylbis(3-(3-
phenylpropanamido)propylcarbamate) (30)
Using general procedure A, reaction of 2-methoxyphenylacetic
acid (36 mg, 0.21 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP
Using general procedure A, reaction of 3-phenylpropionic acid
(38 mg, 0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol), PyBOP (131 mg,
(111 mg, 0.21 mmol), and Et3N (54
m
L, 0.39 mmol) yielded a crude
0.25 mmol), and Et3N (54
mL, 0.39 mmol) yielded a crude product that
product that was purified by silica gel column chromatography
was purified by silica gel column chromatography (2% MeOH/CH2Cl2)

L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
29
to yield 30 (48 mg, 63%) as a colourless oil. Rf (5% MeOH/CH2Cl2) 0.41;
IR nmax (ATR) 3298, 2925, 2854, 1651, 1545, 1477, 1454, 1365, 1158,
(2% MeOH/CH2Cl2) to afford 33 (46 mg, 51% yield) as a colourless oil.
Rf (5% MeOH/CH2Cl2) 0.33; IR nmax (ATR) 3311, 2926, 2854,1650,1514,
732 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d
7.28e7.17 (5H, m, H-2, H-3, H-
1417, 1235, 1155, 1028, 764 cmꢂ1; 1H NMR (CDCl3, 400 MHz)
d 6.82
4, H-5 and H-6), 6.82 (1H, br s, NH-10), 3.21e3.13 (4H, m, H2-11 and
H2-13), 3.08 (2H, t, J ¼ 6.6 Hz, H2-15), 2.97 (2H, t, J ¼ 7.9 Hz, H2-7), 2.49
(2H, t, J ¼ 7.9 Hz, H2-8), 1.61e1.54 (2H, m, H2-12), 1.51e1.46 (2H, m,
H2-16),1.44 (9H, s, 3H3-23),1.27 (8H, br s, H2-17, H2-18, H2-19 and H2-
(1H, br s, NH-10), 6.79e6.73 (3H, m, H-2, H-5 and H-6), 3.86 (3H, s,
OMe-24), 3.84 (3H, s, OMe-25), 3.21e3.13 (4H, m, H2-11 and H2-13),
3.11e3.05 (2H, m, H2-15), 2.92 (2H, t, J ¼ 7.6 Hz, H2-7), 2.47 (2H, t,
J ¼ 7.6 Hz, H2-8), 1.61e1.54 (2H, m, H2-12), 1.52e1.45 (2H, m, H2-16),
1.44 (9H, s, 3H3-23), 1.26 (8H, br s, H2-17, H2-18, H2-19 and H2-20);
20); 13C NMR (CDCl3,100 MHz)
d 172.5 (C-9),156.6 (C-21),141.1 (C-1),
128.7, 128.5, 128.5, 128.4, 126.1 (C-2, C-3, C-4, C-5 and C-6), 79.6 (C-
22), 47.1 (C-15), 43.2 (C-13), 38.6 (C-8), 35.6 (C-11), 31.8 (C-7), 29.7,
29.6, 29.4 (C-18, C-19 and C-20), 28.5 (C-23), 28.5 (C-16), 27.7 (C-12),
26.9 (C-17); (þ)-HRESIMS m/z 779.5643 [M þ H]þ (calcd for
13C NMR (CDCl3, 100 MHz)
d 172.3 (C-9), 156.7 (C-21), 148.9 (C-3),
147.4 (C-4), 133.8 (C-1), 120.3 (C-6), 111.8 (C-2), 111.4 (C-5), 79.6 (C-
22), 56.0 (C-24), 55.9 (C-25), 47.0 (C-15), 43.1 (C-13), 38.9 (C-8), 35.5
(C-11), 31.5 (C-7), 29.7, 29.6, 29.4, 26.9 (C-17, C-18, C-19 and C-20),
28.6 (C-16), 28.5 (C-23), 27.7 (C-12); (þ)-HRESIMS m/z 899.6076
[M þ H]þ (calcd for C50H83N4O10, 899.6104); Purity 99% tR ¼ 7.95 min.
C46H75N4O6, 779.5681); Purity 96% tR ¼ 8.13 min.
5.5.10. Di-tert-butyl dodecane-1,12-diylbis(3-(3-(2-hydroxyphenyl)
propanamido)propylcarbamate) (31)
5.6. Synthesis of diamides 34e45
Using general procedure A, reaction of 3-(2-hydroxyphenyl)
propanoic acid (40 mg, 0.24 mmol), 21 [12,13] (50 mg, 0.10 mmol),
PyBOP (156 mg, 0.30 mmol), and Et3N (55 mL, 0.40 mmol) yielded a
5.6.1. N1,N12-Bis(3-benzamidopropyl)dodecane-1,12-diaminium
2,2,2-trifluoroacetate (34)
crude product that was purified by silica gel column chromatog-
raphy (2% MeOH/CH2Cl2) to afford 31 (20 mg, 25% yield) as a col-
ourless oil. Rf (10% MeOH/CH2Cl2) 0.85; IR nmax (ATR) 3289, 2927,
2855, 1651, 1456, 1419, 1365, 1245, 1153, 751 cmꢂ1; 1H NMR (CDCl3,
Using general procedure B, reaction of 22 (23 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 34 as a colourless oil
(19 mg, 80% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.84; IR nmax (ATR) 3314, 2928, 2855, 1671, 1634,
400 MHz)
d
7.14 (1H, br s, OH-24), 7.10 (1H, dd, J ¼ 7.4, 1.6 Hz, H-6),
1542, 1312, 1199, 1136, 720 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 7.85
7.07 (1H, ddd, J ¼ 7.9, 7.9, 1.6 Hz, H-4), 6.90 (1H, dd, J ¼ 7.9, 1.1 Hz, H-
3), 6.82 (1H, ddd, J ¼ 7.9, 7.4, 1.1 Hz, H-5), 5.74 (1H, br s, NH-10),
3.21e3.13 (4H, m, H2-11 and H2-13), 3.06 (2H, t, J ¼ 7.4 Hz, H2-
15), 2.91 (2H, t, J ¼ 5.7 Hz, H2-7), 2.64 (2H, t, J ¼ 5.7 Hz, H2-8), 1.61e
1.56 (2H, m, H2-12), 1.50e1.44 (2H, m, H2-16), 1.45 (9H, s, 3H3-23),
1.26 (8H, br s, H2-17, H2-18, H2-19 and H2-20); 13C NMR (CDCl3,
(2H, dd, J ¼ 7.8, 1.4 Hz, H-2 and H-6), 7.55 (1H, dddd, J ¼ 8.2, 8.2, 1.4,
1.4 Hz, H-4), 7.47 (2H, ddd, J ¼ 8.2, 7.8, 1.4 Hz, H-3 and H-5), 3.51
(2H, t, J ¼ 6.5 Hz, H2-9), 3.05 (2H, t, J ¼ 7.1 Hz, H2-11), 3.00 (2H, t,
J ¼ 7.7 Hz, H2-13), 1.99 (2H, tt, J ¼ 7.1, 6.5 Hz, H2-10), 1.70 (2H, tt,
J ¼ 7.7, 7.3 Hz, H2-14),1.40e1.33 (8H, m, H2-15, H2-16, H2-17 and H2-
18); 13C NMR (CD3OD, 100 MHz)
d 171.1 (C-7), 135.0 (C-1), 133.0 (C-
100 MHz)
d
174.2 (C-9), 156.8 (C-21), 155.2 (C-2), 130.7 (C-4), 128.3
4), 129.6 (C-3 and C-5), 128.3 (C-2 and C-6), 49.0 (C-13), 46.4 (C-11),
37.5 (C-9), 30.6, 30.5, 30.2 (C-16, C-17 and C-18), 27.8 (C-10), 27.5 (C-
15), 27.3 (C-14); (þ)-HRESIMS m/z 523.3990 [M þ H]þ (calcd for
(C-1), 128.0 (C-6), 120.3 (C-5), 117.8 (C-3), 80.0 (C-22), 47.2 (C-15),
43.5 (C-13), 37.5 (C-8), 36.2 (C-11), 29.7, 29.6, 29.5 (C-18, C-19 and
C-20), 28.6 (C-16), 28.6 (C-23), 27.4 (C-12), 24.7 (C-7), 27.0 (C-17);
(ꢂ)-HRESIMS m/z 809.5427 [M ꢂ H]- (calcd for C46H73N4O8,
809.5434); Purity 96% tR ¼ 7.64 min.
C
32H51N4O2, 523.4007); Purity 99% tR ¼ 6.67 min.
5.6.2. N1,N12-Bis(3-(2-hydroxybenzamido)propyl)dodecane-1,12-
diaminium 2,2,2-trifluoroacetate (35)
5.5.11. Di-tert-butyl dodecane-1,12-diylbis(3-(3-(2,5-
dimethoxyphenyl)propanamido)propylcarbamate) (32)
Using general procedure A, reaction of 3-(2,5-dimethoxyphenyl)
propanoic acid (63 mg, 0.30 mmol), 21 [12,13] (51 mg, 0.10 mmol),
PyBOP (156 mg, 0.30 mmol), and Et3N (111 mL, 0.80 mmol) yielded a
crude product that was purified by silica gel column chromatog-
raphy (2% MeOH/CH2Cl2) to yield 32 (53 mg, 59%) as a colourless oil.
Rf (5% MeOH/CH2Cl2) 0.76; IR nmax (ATR) 3298, 2926, 2854, 1690,
1672, 1646, 1499, 1417, 1222, 1156, 1049, 740 cmꢂ1; 1H NMR (CDCl3,
Using general procedure B, reaction of 23 (20 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) followed by purification by C18
reversed-phase column chromatography (50% MeOH/H2O (þ0.05%
TFA)) afforded 35 as a colourless oil (19 mg, 92% yield). Rf (10%
MeOH/CH2Cl2) 0.36; IR nmax (ATR) 3315, 2929, 2856, 1670, 1634,
1547, 1200, 1133, 722 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 7.77 (1H,
dd, J ¼ 7.8, 1.6 Hz, H-6), 7.39 (1H, ddd, J ¼ 7.4, 7.4, 1.5 Hz, H-4), 6.93e
6.87 (2H, m, H-3 and H-5), 3.53 (2H, t, J ¼ 6.5 Hz, H2-9), 3.06 (2H, t,
J ¼ 7.2 Hz, H2-11), 3.00 (2H, t, J ¼ 7.7 Hz, H2-13), 2.00 (2H, tt, J ¼ 7.2,
6.5 Hz, H2-10), 1.70 (2H, tt, J ¼ 7.7, 7.7 Hz, H2-14), 1.43e1.35 (2H, m,
H2-15), 1.33 (6H, br s, H2-16, H2-17 and H2-18); 13C NMR (CD3OD,
400 MHz)
d 6.77e6.74 (3H, m, H-3, H-6 and NH-10), 6.69 (1H, dd,
J ¼ 8.8, 2.9 Hz, H-4), 3.79 (3H, s, OMe-24), 3.74 (1H, s, OMe-25),
3.21e3.14 (4H, m, H2-11 and H2-13), 3.11e3.06 (2H, m, H2-15),
2.92 (2H, t, J ¼ 7.8 Hz, H2-7), 2.47 (2H, t, J ¼ 7.8 Hz, H2-8), 1.62e1.55
(2H, m, H2-12), 1.52e1.45 (2H, m, H2-16), 1.44 (9H, s, 3H3-23), 1.26
(8H, br s, H2-17, H2-18, H2-19 and H2-20); 13C NMR (CDCl3,
100 MHz)
d 171.7 (C-7), 160.9 (C-2), 135.0 (C-4), 129.2 (C-6), 120.2
(C-5), 118.4 (C-3), 116.9 (C-1), 49.2 (C-13), 46.4 (C-11), 37.0 (C-9),
30.6, 30.5, 30.2 (C-16, C-17 and C-18), 27.7 (C-10), 27.5 (C-15), 27.3
(C-14); (þ)-HRESIMS m/z 555.3873 [M þ H]þ (calcd for C32H51N4O4,
555.3910); Purity 99% tR ¼ 6.91 min.
100 MHz)
d 172.7 (C-9), 156.7 (C-21), 153.6 (C-5), 151.8 (C-2), 130.6
(C-1), 116.3 (C-6), 111.8 (C-4), 111.4 (C-3), 79.6 (C-22), 56.0 (C-24),
55.8 (C-25), 47.1 (C-15), 43.3 (C-13), 37.0 (C-8), 35.7 (C-11), 29.7,
29.6, 29.5 (C-18, C-19 and C-20), 28.5 (C-23), 28.5 (C-16), 27.8 (C-
12), 27.1 (C-7), 27.0 (C-17); (þ)-HRESIMS m/z 921.5889 [M þ Na]þ
(calcd for C50H82N4NaO10, 921.5923); Purity 97% tR ¼ 8.13 min.
5.6.3. N1,N12-Bis(3-(2,5-dimethoxybenzamido)propyl)dodecane-
1,12-diaminium 2,2,2-trifluoroacetate (36)
Using general procedure B, reaction of 24 (38.0 mg, 0.05 mmol)
in CH2Cl2 (2 mL) with TFA (0.2 mL) followed by purification by C18
reversed-phase column chromatography (50% MeOH/H2O (þ0.05%
TFA)) afforded 36 as a colourless oil (34.0 mg, 87% yield). Rf (10%
MeOH/CH2Cl2) 0.82; IR nmax (ATR) 3375, 2930, 2856, 1674, 1640,
5.5.12. Di-tert-butyl dodecane-1,12-diylbis(3-(3-(3,4-
dimethoxyphenyl)propanamido)propylcarbamate) (33)
Using general procedure A, reaction of 3-(3,4-dimethoxyphenyl)
propionic acid (53 mg, 0.25 mmol), 21 [12,13] (50 mg, 0.10 mmol),
1494, 1200, 1174, 721 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 7.48 (1H,
d, J ¼ 1.8 Hz, H-6), 7.10e7.05 (2H, m, H-3 and H-4), 3.92 (3H, s, OMe-
19), 3.78 (3H, s, OMe-20), 3.54 (2H, t, J ¼ 6.5 Hz, H2-9), 3.05 (2H, t,
J ¼ 7.2 Hz, H2-11), 3.00 (2H, t, J ¼ 7.7 Hz, H2-13), 1.99 (2H, tt, J ¼ 7.2,
PyBOP (131 mg, 0.25 mmol), and Et3N (54
mL, 0.39 mmol) yielded a
crude product that was purified by silica gel column chromatography

30
L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
6.5 Hz, H2-10), 1.70 (2H, tt, J ¼ 7.7, 7.2 Hz, H2-14), 1.45e1.36 (2H, m,
(20.0 mg, 96% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.54; IR nmax (ATR) 3284, 2929, 2855, 1673, 1638,
H2-15), 1.32 (6H, br s, H2-16, H2-17 and H2-18); 13C NMR (CD3OD,
100 MHz)
d
169.0 (C-7), 155.1 (C-5), 153.3 (C-2), 123.0 (C-1), 119.7
1514, 1199, 1138, 1032, 720 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 7.21
(C-4), 116.8 (C-6), 114.2 (C-3), 56.9 (C-19), 56.2 (C-20), 49.2 (C-13),
46.3 (C-11), 37.3 (C-9), 30.6, 30.5, 30.2 (C-16, C-17 and C-18), 27.7 (C-
10), 27.5 (C-15), 27.3 (C-14); (þ)-HRESIMS m/z 643.4394 [M þ H]þ
(calcd for C36H59N4O6, 643.4435); Purity 99% tR ¼ 6.92 min.
(2H, dd, J ¼ 8.7, 2.9 Hz, H-2 and H-6), 6.87 (2H, dd, J ¼ 8.7, 2.9 Hz, H-
3 and H-5), 3.77 (3H, s, OMe-20), 3.45 (2H, s, H2-7), 3.29 (2H, t,
J ¼ 6.5 Hz, H2-10), 2.90e2.85 (4H, m, H2-12 and H2-14), 1.84 (2H, tt,
J ¼ 6.5, 6.5 Hz, H2-11), 1.65e1.58 (2H, m, H2-15), 1.33 (8H, br s, H2-
16, H2-17, H2-18 and H2-19); 13C NMR (CD3OD, 100 MHz)
d 175.8 (C-
5.6.4. N1,N12-Bis(3-(2-phenylacetamido)propyl)dodecane-1,12-
diaminium 2,2,2-trifluoroacetate (37)
8), 160.3 (C-4), 131.1 (C-2 and C-6), 128.8 (C-1), 115.1 (C-3 and C-5),
55.7 (C-20), 49.1 (C-14), 46.1 (C-12), 42.9 (C-7), 36.9 (C-10), 30.6,
30.5, 30.2 (C-17, C-18 and C-19), 27.6 (C-11), 27.5 (C-16), 27.2 (C-15);
(þ)-HRESIMS m/z 611.4495 [M þ H]þ (calcd for C36H59N4O4,
611.4531); Purity 98% tR ¼ 6.38 min.
Using general procedure B, reaction of 25 (22 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 37 (22 mg, 96% yield) as a
colourless oil which required no further purification. Rf (10% MeOH/
CH2Cl2) 0.35; IR nmax (ATR) 3273, 2929, 2856, 1643, 1554, 1435, 1136,
720 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d
7.33e7.29 (4H, m, H-2, H-3,
5.6.8. N1,N12-Bis(3-(2-(2,5-dimethoxyphenyl)acetamido)propyl)
dodecane-1,12-diaminium 2,2,2-trifluoroacetate (41)
Using general procedure B, reaction of 29 (38 mg, 0.04 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 41 as a colourless oil
(28 mg, 71% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.55; IR nmax (ATR) 3290, 2930, 2855, 1671, 1650,
1501, 1226, 1199, 1174, 1024, 719 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
H-5 and H-6), 7.28e7.22 (1H, m, H-4), 3.53 (2H, s, H2-7), 3.30 (2H, t,
J ¼ 6.9 Hz, H2-10), 2.91e2.85 (4H, m, H2-12 and H2-14), 1.85 (2H, tt,
J ¼ 6.9, 6.9 Hz, H2-11),1.62 (2H, tt, J ¼ 7.4, 7.1 Hz, H2-15),1.30 (8H, br s,
H2-16, H2-17, H2-18 and H2-19); 13C NMR (CD3OD, 100 MHz)
d 175.4
(C-8),136.9 (C-1),130.1 (C-2 and C-6),129.7 (C-3 andC-5),128.1 (C-4),
49.3 (C-14), 46.1 (C-12), 43.8 (C-7), 36.9 (C-10), 30.6 (C-17, C-18 andC-
19), 27.6 (C-11), 27.5 (C-16), 27.2 (C-15); (þ)-HRESIMS m/z 551.4286
[M þ H]þ (calcd for C34H55N4O2, 551.4325); Purity 99% tR ¼ 6.48 min.
d
6.89 (1H, d, J ¼ 7.9 Hz, H-3), 6.82e6.78 (2H, m, H-4 and H-6), 3.79
(3H, s, OMe-20), 3.74 (3H, s, OMe-21) 3.51 (2H, s, H2-7), 3.30 (2H,
obsc. H2-10), 2.94 (2H, t, J ¼ 7.1 Hz, H2-12), 2.88 (2H, t, J ¼ 7.7 Hz, H2-
14), 1.85 (2H, tt, J ¼ 7.1, 6.8 Hz, H2-11), 1.62 (2H, tt, J ¼ 7.7, 7.1 Hz, H2-
15), 1.31 (8H, br s, H2-16, H2-17, H2-18 and H2-19); 13C NMR (CD3OD,
5.6.5. N1,N12-Bis(3-(2-(2-hydroxyphenyl)acetamido)propyl)
dodecan-1,12-diaminium 2,2,2-trifluoroacetate (38)
Using general procedure B, reaction of 26 (20 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 38 as a colourless oil
(20 mg, 96% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.34; IR nmax (ATR) 3090, 2929, 2856, 1670, 1642,
100 MHz) d 175.5 (C-8),155.1 (C-5),153.1 (C-2),125.9 (C-1),118.6 (C-
6), 113.8 (C-4), 112.7 (C-3), 56.5 (C-20), 56.1 (C-21), 49.3 (C-14), 45.9
(C-12), 38.7 (C-7), 36.7 (C-10), 30.6, 30.5, 30.2 (C-17, C-18 and C-19),
27.7 (C-11), 27.5, (C-16), 27.2 (C-15); (þ)-HRESIMS m/z 671.4716
1457, 1200, 1178, 1134, 721 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d
7.14
[M
þ
H]þ (calcd for C38H63N4O6, 671.4748); Purity 99%
(1H, dd, J ¼ 8.7, 1.8 Hz, H-6), 7.09 (1H, dd, J ¼ 7.7, 1.8 Hz, H-4), 6.82e
6.79 (2H, m, H-3 and H-5), 3.54 (2H, s, H2-7), 3.32 (2H, obsc. H2-10),
2.96 (2H, t, J ¼ 6.9 Hz, H2-12), 2.88 (2H, t, J ¼ 7.0 Hz, H2-14),1.85 (2H,
tt, J ¼ 6.9, 6.6 Hz, H2-11), 1.62 (2H, tt, J ¼ 7.4, 7.0 Hz, H2-15), 1.32 (8H,
br s, H2-16, H2-17, H2-18 and H2-19); 13C NMR (CD3OD, 100 MHz)
tR ¼ 6.30 min.
5.6.9. N1,N12-Bis(3-(3-phenylpropanamido)propyl)dodecane-1,12-
diaminium 2,2,2-trifluoroacetate (42)
Using general procedure B, reaction of 30 (31 mg, 0.04 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 42 as a colourless oil
(31 mg, 97% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.53; IR nmax (ATR) 3290, 2928, 2856, 1671, 1646,
d
176.2 (C-8), 156.7 (C-2), 132.3 (C-6), 129.6 (C-4), 123.2 (C-1), 120.8
(C-5), 116.2 (C-3), 49.2 (C-14), 45.9 (C-12), 39.1 (C-7), 36.6 (C-10),
30.6, 30.5, 30.2 (C-17, C-18 and C-19), 27.6 (C-11), 27.5 (C-16), 27.2
(C-15); (þ)-HRESIMS m/z 583.4190 [M þ H]þ (calcd for C34H55N4O4,
583.4223); Purity 99% tR ¼ 5.70 min.
1200, 1174, 1138, 721 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 7.29e7.16
(5H, m, H-2, H-3, H-4, H-5 and H-6), 3.24 (2H, t, J ¼ 6.6 Hz, H2-11),
2.93 (2H, t, J ¼ 7.5 Hz, H2-7), 2.86 (2H, t, J ¼ 7.6 Hz, H2-15), 2.75 (2H,
t, J ¼ 7.0 Hz, H2-13), 2.55 (2H, t, J ¼ 7.5 Hz, H2-8), 1.77 (2H, tt, J ¼ 7.0,
6.6 Hz, H2-12), 1.66 (2H, tt, J ¼ 7.6, 7.3 Hz, H2-16), 1.41e1.35 (2H, m,
H2-17), 1.35 (6H, br s, H2-18, H2-19 and H2-20); 13C NMR (CD3OD,
5.6.6. N1,N12-Bis(3-(2-(2-methoxyphenyl)acetamido)propyl)
dodecane-1,12-diaminium 2,2,2-trifluoroacetate (39)
Using general procedure B, reaction of 27 (20 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 39 as a colourless oil
(20 mg, 90% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.33; IR nmax (ATR) 3284, 3071, 2927, 2852, 1663,
1634, 1492, 1247, 1198, 1143, 720 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
100 MHz)
d 176.3 (C-9), 142.0 (C-1), 129.5, 129.4, 127.3 (C-2 to C-6),
49.1 (C-15), 46.0 (C-13), 38.3 (C-8), 36.6 (C-11), 32.6 (C-7), 30.6,
30.5, 30.2 (C-18, C-19 and C-20), 27.6 (C-12), 27.5 (C-17), 27.3 (C-16);
(þ)-HRESIMS m/z 579.4597 [M þ H]þ (calcd for C36H59N4O2,
579.4633); Purity 99% tR ¼ 6.67 min.
d
7.65 (1H, ddd, J ¼ 8.2, 8.2, 1.5 Hz, H-4), 7.20 (1H, dd, J ¼ 7.4, 1.4 Hz,
H-6), 6.97 (1H, d, J ¼ 8.2 Hz, H-3), 6.92 (1H, ddd, J ¼ 8.2, 7.4,1.4 Hz, H-
5), 3.83 (3H, s, OMe-20), 3.54 (2H, s, H2-7), 3.29 (2H, t, J ¼ 6.7 Hz, H2-
10), 2.94 (2H, t, J ¼ 7.0 Hz, H2-12), 2.88 (2H, t, J ¼ 7.7 Hz, H2-14), 1.85
(2H, tt, J ¼ 7.0, 6.7 Hz, H2-11), 1.60 (2H, tt, J ¼ 7.7, 6.7 Hz, H2-15), 1.31
(8H, br s, H2-16, H2-17, H2-18 and H2-19); 13C NMR (CD3OD,
5.6.10. N1,N12-Bis(3-(3-(2-hydroxyphenyl)propanamido)propyl)
dodecane-1,12-diaminium 2,2,2-trifluoroacetate (43)
Using general procedure B, reaction of 31 (14 mg, 0.02 mmol)
in CH2Cl2 (2 mL) with TFA (0.2 mL) followed by purification by C18
reversed-phase column chromatography (50% MeOH/H2O (TFA))
afforded 43 as a colourless oil (10 mg, 90% yield). Rf (10% MeOH/
CH2Cl2) 0.46; IR nmax (ATR) 3302, 2931, 2857, 1671, 1441, 1182,
100 MHz) d 175.7 (C-8).159.0 (C-2),132.2 (C-6),129.8 (C-4),124.9 (C-
1), 121.8 (C-5), 111.7 (C-3), 55.9 (C-20), 48.9 (C-14), 46.0 (C-12), 38.6
(C-7), 36.8 (C-10), 30.6, 30.5, 30.2 (C-17, C-18 and C-19), 27.7 (C-11),
27.5 (C-16), 27.2 (C-15); (þ)-HRESIMS m/z 611.4506 [M þ H]þ (calcd
for C36H59N4O4, 611.4531); Purity 99% tR ¼ 6.98 min.
1135, 724 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d
7.07 (1H, dd, J ¼ 7.4,
1.5 Hz, H-6), 7.02 (1H, ddd, J ¼ 7.8, 7.8, 1.5 Hz, H-4), 6.77e6.71 (1H,
m, H-3 and H-5), 3.25 (2H, t, J ¼ 6.5 Hz, H2-11), 2.93e2.86 (4H, m,
H2-7 and H2-15), 2.79 (2H, t, J ¼ 7.2 Hz, H2-13), 2.56 (2H, t,
J ¼ 7.4 Hz, H2-8), 1.78 (2H, tt, J ¼ 7.2, 6.5 Hz, H2-12), 1.66 (2H, tt,
J ¼ 7.2, 6.4 Hz, H2-16), 1.38 (8H, br s, H2-17, H2-18, H2-19 and H2-
5.6.7. N1,N12-Bis(3-(2-(4-methoxyphenyl)acetamido)propyl)
dodecane-1,12-diaminium 2,2,2-trifluoroacetate (40)
Using general procedure B, reaction of 28 (20.0 mg, 0.02 mmol)
in CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 40 as a colourless oil
20); 13C NMR (CD3OD, 100 MHz)
d 177.2 (C-9), 156.5 (C-2), 131.1

L.P.P. Liew et al. / European Journal of Medicinal Chemistry 69 (2013) 22e31
31
(C-6), 128.6 (C-4), 128.1 (C-1), 120.5 (C-5), 116.1 (C-3), 49.2 (C-15),
46.0 (C-13), 36.8 (C-8), 36.6 (C-11), 30.6, 30.5, 30.2 (C-18, C-19 and
C-20), 27.7 (C-12), 27.5 (C-7), 27.5 (C-17), 27.3 (C-16); (þ)-HRE-
SIMS m/z 611.4501 [M þ H]þ (calcd for C36H59N4O4, 611.4531);
Purity 98% tR ¼ 6.84 min.
0 with GFP-transfected P. berghei strain ANKA [17]. Compounds
were formulated in 100% DMSO, diluted 10-fold in distilled water
and administered intraperitoneally in a volume of 10 ml/kg on four
consecutive days (4, 24, 48 and 72 h post infection). Parasitaemia
was determined on day 4 post infection (24 h after last treatment)
by FACS analysis. Activity was calculated as the difference between
the mean per cent parasitaemia for the control (n ¼ 5 mice) and
treated groups expressed as a per cent relative to the control group.
The survival of the animals was usually monitored up to 30 days,
but in the current study all mice were euthanized after the deter-
mination of parasitaemia due to inactivity. A compound was
considered curative if the animal survived to day 30 after infection
with no detectable parasites. All protocols and procedures used in
the current study were reviewed and approved by the local veter-
inary authorities of the Canton Basel-Stadt.
5.6.11. N1,N12-Bis(3-(3-(2,5-dimethoxyphenyl)propanamido)
propyl)dodecane-1,12-diaminium 2,2,2-trifluoroacetate (44)
Using general procedure B, reaction of 32 (25 mg, 0.03 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) afforded 44 as a colourless oil
(18 mg, 95% yield) which required no further purification. Rf (10%
MeOH/CH2Cl2) 0.75; IR nmax (ATR) 3285, 2931, 2855, 1672, 1650,
1500, 1200, 1127, 720 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d 6.84 (1H,
d, J ¼ 7.9 Hz, H-3), 6.75e6.72 (2H, m, H-4 and H-6), 3.78 (3H, s,
OMe-21), 3.72 (3H, s, OMe-22), 3.24 (2H, t, J ¼ 6.5 Hz, H2-15), 2.91e
2.86 (4H, m, H2-7 and H2-11), 2.81 (2H, t, J ¼ 7.1 Hz, H2-13), 2.52
(2H, t, J ¼ 7.3 Hz, H2-8), 1.78 (2H, tt, J ¼ 7.1, 6.5 Hz, H2-12), 1.67 (2H,
tt, J ¼ 7.4, 7.1 Hz, H2-16), 1.42e1.30 (8H, m, H2-17, H2-18, H2-19 and
Acknowledgements
H2-20); 13C NMR (CD3OD, 100 MHz)
d 176.8 (C-9), 154.9 (C-5), 153.2
We acknowledge funding from the University of Auckland (FDRF
3626196 and Biopharma Thematic Research Initiative) and thank
M. Cal, and S. Sax (Swiss TPH) for assistance with parasitic assays,
Dr C. J. Janse (Leiden University) for providing the GFP transfected
P. berghei strain, Dr M. Schmitz for assistance with NMR data
acquisition, and Ms. R. Imatdieva for MS data.
(C-2), 131.1 (C-1), 117.7 (C-6), 112.5 (C-4), 112.4 (C-3), 49.2 (C-15),
46.0 (C-13), 36.7 (C-8), 36.6 (C-11), 30.6, 30.5, 30.2 (C-18, C-19 and
C-20), 27.7 (C-7), 27.7 (C-12), 27.5 (C-17), 27.3 (C-16); (þ)-HRESIMS
m/z 699.5001 [M þ H]þ (calcd for C40H67N4O6, 699.5055); Purity
99% tR ¼ 6.26 min.
5.6.12. N1,N12-Bis(3-(3-(3,4-dimethoxyphenyl)propanamido)
propyl)dodecane-1,12-diaminium 2,2,2-trifluoroacetate (45)
Using general procedure B, reaction of 33 (34 mg, 0.04 mmol) in
CH2Cl2 (2 mL) with TFA (0.2 mL) followed by purification by C18
reversed-phase column chromatography (50% MeOH/H2O (TFA))
afforded 45 as a colourless oil (31 mg, 88% yield). Rf (10% MeOH/
CH2Cl2) 0.68; IR nmax (ATR) 3291, 2930, 2856, 1673,1648,1515,1200,
Appendix A. Supplementary data
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.ejmech.2013.07.
055. These data include MOL files and InChiKeys of the most
important compounds described in this article.
1177, 721 cmꢂ1; 1H NMR (CD3OD, 400 MHz)
d
6.86 (1H, d, J ¼ 8.2 Hz,
H-5), 6.83 (1H, d, J ¼ 1.9 Hz, H-2), 6.76 (1H, dd, J ¼ 8.2, 1.9 Hz, H-6),
3.84 (3H, s, OMe-21), 3.79 (3H, s, OMe-22), 3.24 (2H, t, J ¼ 6.5 Hz,
H2-11), 2.89e2.83 (4H, m, H2-7 and H2-15), 2.76 (2H, t, J ¼ 7.1 Hz,
H2-13), 2.53 (2H, t, J ¼ 7.4 Hz, H2-8), 1.78 (2H, tt, J ¼ 7.1, 6.5 Hz, H2-
12), 1.65 (2H, tt, J ¼ 7.1, 7.0 Hz, H2-16), 1.34 (8H, br s, H2-17, H2-18,
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H2-19 and H2-20); 13C NMR (CD3OD, 100 MHz)
d 176.7 (C-9), 150.4
(C-3), 149.0 (C-4), 134.9 (C-1), 121.7 (C-6), 113.7 (C-2), 113.3 (C-5),
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chloroquine as the positive control (IC50 of 0.20
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(37.3 g/mL). Protocols for these assays have been reported else-
mM (0.065 mg/mL)).
m
m
mM
m
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where [5].
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5.7.2. In vivo antimalarial efficacy studies
In vivo antimalarial activity was assessed as previously
described [15]. Groups of three female NMRI mice (20e22 g) were
intravenously infected with 2 ꢁ 107 parasitized erythrocytes on day