Bisquinolines. 2. Antimalarial N,N-Bis(7-chloroquinolin-4- yl)heteroalkanediamines

Article abstract of DOI:10.1021/jm9803828

N,N-Bis(7-chloroquinolin-4-yl)heteroalkanediamines 1-11 were synthesized and screened against Plasmodium falciparum in vitro and Plasmodium berghei in vivo. These bisquinolines had IC₅₀ values from 1 to 100 nM against P. falciparum in vitro. Six of the 11 bisquinolines were significantly more potent against the chloroquine-resistant W2 clone compared to the chloroquine-sensitive D6 clone. For bisquinolines 1-11 there was no relationship between the length of the bisquinoline heteroalkane bridge and antimalarial activity and no correlation between in vitro and in vivo antimalarial activities. Bisquinolines with alkyl ether and piperazine bridges were substantially more effective than bisquinolines with alkylamine bridges against P. berghei in vivo. Bisquinolines 1-10 were potent inhibitors of hematin polymerization with IC₅₀ values falling in the narrow range of 5-20 μM, and there was a correlation between potency of inhibition of hematin polymerization and inhibition of parasite growth. Compared to alkane- bridged bisquinolines (Vennerstrom et al., 1992), none of these heteroalkane- bridged bisquinolines had sufficient antimalarial activity to warrant further investigation of the series.

Full text of DOI:10.1021/jm9803828

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4360
J . Med. Chem. 1998, 41, 4360-4364
Bisqu in olin es. 2. An tim a la r ia l
N,N-Bis(7-ch lor oqu in olin -4-yl)h eter oa lk a n ed ia m in es
J onathan L. Vennerstrom,*,† Arba L. Ager, J r.,§ Arnulf Dorn,| Steven L. Andersen,‡ Lucia Gerena,‡
Robert G. Ridley,| and Wilbur K. Milhous‡
College of Pharmacy, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, Nebraska 68198-6025,
Department of Microbiology and Immunology, University of Miami School of Medicine, Miami, Florida 33136,
Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Washington, D.C., 20307-5100,
and Pharma Division, Preclinical Research, F. Hoffmann-LaRoche Ltd., CH-4070 Basel, Switzerland
Received J une 24, 1998
N,N-Bis(7-chloroquinolin-4-yl)heteroalkanediamines 1-11 were synthesized and screened
against Plasmodium falciparum in vitro and Plasmodium berghei in vivo. These bisquinolines
had IC50 values from 1 to 100 nM against P. falciparum in vitro. Six of the 11 bisquinolines
were significantly more potent against the chloroquine-resistant W2 clone compared to the
chloroquine-sensitive D6 clone. For bisquinolines 1-11 there was no relationship between
the length of the bisquinoline heteroalkane bridge and antimalarial activity and no correlation
between in vitro and in vivo antimalarial activities. Bisquinolines with alkyl ether and
piperazine bridges were substantially more effective than bisquinolines with alkylamine bridges
against P. berghei in vivo. Bisquinolines 1-10 were potent inhibitors of hematin polymerization
with IC50 values falling in the narrow range of 5-20 µM, and there was a correlation between
potency of inhibition of hematin polymerization and inhibition of parasite growth. Compared
to alkane-bridged bisquinolines (Vennerstrom et al., 1992), none of these heteroalkane-bridged
bisquinolines had sufficient antimalarial activity to warrant further investigation of the series.
Although bisquinolines such as piperaquine, hydrox-
ypiperaquine, and dichloroquinazine are active against
chloroquine-resistant Plasmodium falciparum, none
have seen extensive clinical use in malaria chemo-
therapy.1 Several years ago we initiated a reinvestiga-
tion of antimalarial bisquinolines when we disclosed
antimalarial data for 13 new N,N-bis(7-chloroquinolin-
4-yl)alkanediamines.2 Six of the 13 bisquinolines had
superior in vitro and in vivo antimalarial activity
compared to chloroquine, and one, (()-trans-N1,N2-bis-
(7-chloroquinolin-4-yl)cyclohexane-1,2-diamine, was uni-
quely effective. This bisquinoline, WR 268,668 (Ro 48-
6910), is a very effective inhibitor of hematin polymer-
ization3 and, like chloroquine and other antimalarial
4-aminoquinolines,3,4 may exert its antimalarial proper-
ties by this mechanism. Although a subsequent study5
revealed some cross-resistance between bisquinoline WR
268,668 and chloroquine in vitro, its S,S enantiomer (Ro
47-7737) underwent extensive preclinical evaluation at
F. Hoffmann-LaRoche Ltd.,6 but phototoxicity precluded
its further development.
antimalarial properties of three analogues of WR 268,-
668, while Cowman et al.9 described the excellent
activity of a novel bisquinolinemethanol which was
regrettably too toxic for further investigation. Raynes
et al.7 prepared nine bisquinoline bisamides with low
resistance indices, the most potent of which had IC50
values in the 100 nM range against P. falciparum in
vitro. A subsequent investigation10 revealed an excel-
lent correlation between inhibition of parasite growth
and inhibition of hematin polymerization for these nine
bisquinolines.
In this work, we describe the synthesis of a series of
11 N,N-bis(7-chloroquinolin-4-yl)heteroalkanediamine
bisquinolines and examine the effects of incorporating
oxygen and nitrogen atoms in the alkane bridge on
antimalarial activity and inhibition of hematin polym-
erization.
Ch em istr y
Bisquinolines 1-10 were obtained in yields of 12-
86% (Table 1) via a displacement reaction with 4,7-
dichloroquinoline, heteroalkanediamine, and triethy-
lamine in a 2:1:2 molar ratio in refluxing N-methyl-
pyrrolidinone.2,11 Bisquinolines 1-10 were isolated
by adding water and ethyl ether or ethyl acetate to
the cooled reaction mixtures which initiated product
precipitation and dissolved any unreacted starting
materials. In some cases, crystallization was required
to obtain an analytically pure sample (Table 1). Bis-
quinoline 11 was obtained by treatment of 7-chloro-4-
(piperazin-1-yl)quinoline (12)12 with aqueous formalde-
hyde. For only bisquinoline 9 was flash column
chromatography required for purification. For the alkyl
ether-bridged bisquinolines 1-4, melting point de-
creased as the length of the bridge increased; a similar
Nevertheless, interest in antimalarial bisquinolines
continues.7-9 For example, Ismail et al.8 disclosed the
† University of Nebraska Medical Center.
‡ Walter Reed Army Institute of Research.
§ University of Miami.
| F. Hoffmann-LaRoche Ltd.
10.1021/jm9803828 CCC: $15.00 © 1998 American Chemical Society
Published on Web 09/25/1998

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Antimalarial Bisquinolines
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 22 4361
Ta ble 1. Heteroalkane-Bridged Bisquinolines 1-11
yield
(%)
crystallization
solvent
compd
R
mp (°C)
1
2
3
4
5
6
7
8
9
HN(CH2)2O(CH2)2NH
257-262 dec
181-182
33
79
86
23
33
37
26
50
12
54
HN(CH2)2O(CH2)2O(CH2)2NH
HN(CH2)3O(CH2)4O(CH2)3NH
HN(CH2)3O(CH2)2O(CH2)2O(CH2)3NH
HN(CH2)2NH(CH2)2NH
HN(CH2)3NH(CH2)2NH
HN(CH2)3NH(CH2)3NH
CH3CN
156-166a
99-106
CH3CN
EtOH
MeOH
EtOH
248-253 dec
255-258 dec
199-201b
162-167c
134-137
HN(CH2)3NCH3(CH2)3NH
HN(CH2)6NH(CH2)6NH
CH3CN
10
216-218
11
237-239
65
CH3CN/CHCl3
a
b
Lit.19 mp 124-126 °C. Softening at 76-85 °C. c Softening at 115-118 °C.
Ta ble 2. Antimalarial Activity and Inhibition of Hematin Polymerization for Bisquinolines 1-11
hematin
polymerization
IC50 (µM)
P. falciparum
IC50 (nM)
D6, W2
number of P. berghei-infected mice dead/day dieda
compd
40 mg/kgb
160 mg/kg
640 mg/kg
1
2
3
4
5
6
7
8
20 ( 1
15 ( 1
19 ( 1
20 ( 1
20 ( 1
16 ( 2
14 ( 1
8 ( 1
16, 89
2.5, 9.9
22, 21
1/7 3/8 1/10
2/7 2/9 1/13
1/7 1/8 2/9 1/10
1/8 3/9 1/11
4/6 1/7
4/6 1/7
2/6 3/7
2/8 2/9 1/11
4/6 1/7
1/8 1/9 1/12 2/13
1/6 4/7
1/8 2/9 1/10 1/18
3/8 1/9 1/C
2/10 1/11 1/12 1/26
2/12 1/13 2/14
3/6 1/7 1/11
5/6
1/6 3/7 1/8
3/13 2/18
2/6 3/7
2/13 1/14 1/24 1/29c
1/T 1/6 1/13 1/15 1/C
3/12 2/13
24, 48
1/14 1/19 3/Cc
3/6 2/7
30, 8.9
26, 7.0
86, 26
5.9, 2.8
11, 5.4
1.2, 9.0
>1000, >1000
6.5, 99
5/6
3/8 1/10 1/12
1/12 1/13 1/14 1/16 1/33
5/7
1/16 1/18 1/20 1/22 1/C
1/14 1/22 3/C
3/T 1/25 1/C
9
10
11
7 ( 1
5 ( 1
>2500
80 ( 3
3/13 1/14 1/17 1/C
3/9 1/10 1/16
1/16 1/18 1/20 1/23 1/C
chloroquined
1/12 2/14 1/15 1/16
a
Controls died on day 6 or 7 postinfection, survival beyond 60 days was considered curative (C), and deaths from 0-2 days posttreatment
were attributed to toxicity (T). Compounds were administered in a single sc dose 3 days postinfection, n ) 5. c Skin lesions observed at
site of injection. In vivo data for chloroquine was obtained from multiple experiments at WRAIR.
b
d
trend was observed for the secondary alkylamine-
In h ibition of Hem a tin P olym er iza tion
bridged bisquinolines 5-7 and 9.
Bisquinolines 1-10 were potent inhibitors of hematin
polymerization with IC50 values falling in the narrow
range of 5-20 µM (Table 2). The complete lack of
inhibition of hematin polymerization for bisquinoline 11
corresponded to its complete lack of activity against P.
falciparum in vitro. We next analyzed our data to
assess if the potency of inhibition of hematin polymer-
ization by these bisquinolines correlated with the po-
tency of inhibition of parasite growth in culture. As it
is probable that resistance to 4-aminoquinolines (and
perhaps bis(4-aminoquinolines)) is associated with re-
duced drug permeability,13 we took the lowest IC50 value
against the D6 and W2 parasite clones for a given
bisquinoline to use in the analysis, assuming that drug
uptake was optimal for that clone. For bisquinolines
1-10 we observed a modest correlation (r ) 0.61, p )
0.06) between the potency of inhibition of hematin
polymerization and inhibition of parasite growth.14
An tim a la r ia l Activity
These bisquinolines had IC50 values from 1 to 100 nM
against P. falciparum in vitro (Table 2). Only bisquino-
lines 1, 2, and 10 were cross-resistant with chloroquine,
but in each case the potency difference between the D6
and W2 clones was less than that observed for chloro-
quine. Bisquinolines 3 and 4 were roughly equipotent
against the two P. falciparum clones, while the remain-
ing compounds were more active against the chloro-
quine-resistant W2 clone. For bisquinolines 1-11, there
was a poor correlation between in vitro and in vivo
antimalarial activities, especially evident for bisquino-
line 11. It was also clear that those bisquinolines with
alkyl ether (1-4) and piperazine (10, 11) bridges were
substantially more effective than bisquinolines with
alkylamine (5-9) bridges against Plasmodium berghei
in vivo. There was no relationship between the length
of the bisquinoline heteroalkane bridge and antimalarial
activity. Skin lesions at the site of injection were
observed for bisquinolines 1 and 4 at the 640 mg/kg
dose.
Discu ssion
On balance, incorporation of nitrogen and oxygen
atoms in the bisquinoline bridge did not improve anti-
malarial activity in these bisquinolines. If one compares

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4362 J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 22
Vennerstrom et al.
disks on a Perkin Elmer 1420 spectrophotometer. NMR
spectra were obtained with either Varian XL-300 or Bruker
AC-200 spectrometers using deuteriated dimethyl sulfoxide
for 1-9 and deuteriated chloroform for 10 and 11 with TMS
as an internal standard. It was not possible to obtain 13C NMR
spectra for 1 due to its low solubility in DMSO. Microanalyses
were performed by M-H-W Laboratories, Phoenix, AZ. The
purity of 1-11 was confirmed with silica gel (75:24:1 CHCl3-
CH3OH-NH4OH) or alumina (95:5 CHCl3-CH3OH) TLC. The
heteroalkanediamines were obtained from Aldrich Chemical
Co., E. I. DuPont De Nemours and Co. Inc., BASF Corp., and
the Texaco Chemical Co. 7-Azatridecane-1,13-diamine (Du-
Pont BHMT amine) was purified by vacuum distillation. All
other reagents were obtained from Aldrich Chemical Co.
the activity of each of these heteroalkane-bridged bis-
quinolines with their alkane-bridged bisquinoline coun-
terparts described earlier,2 only for ether-bridged bis-
quinolines 2-4 was in vivo antimalarial efficacy
enhanced, and only for bisquinoline 9 was in vitro
antimalarial potency increased. The ether functional
groups in 2-4 may have endowed these bisquinolines
with increased water solubility and perhaps better
absorption compared to their purely alkane-bridged
analogues.2 For the remaining heteroalkane-bridged
bisquinolines, activity was no better or in some cases
was substantially lower. This loss of in vivo antima-
larial activity was especially notable for bisquinolines
5-9 with amine functional groups in the connecting
bridge. We suspect that this structural feature probably
allows for rapid N-dealkylation metabolism which would
convert these bisquinolines to monoquinolines. Bis-
quinolines 5-9 would thus offer no advantages over
chloroquine and other monoquinolines, as monoquino-
line metabolic products are uniformly less active than
the parent drug, particularly against drug-resistant
parasites.15
Syn th esis of 1-10. A solution of 4,7-dichloroquinoline (10
mmol, 1.98 g), triethylamine (10 mmol, 1.01 g), and diamino-
heteroalkane (5 mmol) in N-methylpyrrolidinone (10 mL) was
subject to 10 purge cycles using a Firestone valve and then
heated to reflux for 2-6 h under a slight positive N2 pressure.
After the reaction mixture cooled to room temperature, ether
or ethyl acetate (15 mL) and water (15 mL) were added with
stirring, and the resulting solid was filtered and washed with
water and ethyl acetate or ether to provide 1-10. In some
cases, cooling of this two-phase mixture was required to induce
precipitation of product.
The hypothesis that bisquinolines3,10 inhibit parasite
growth via inhibition of hematin polymerization is
supported by our data. However, this also requires that
these diprotic and triprotic bisquinolines, like the dipro-
tic weak base chloroquine,16 concentrate to micromolar
levels in the food vacuole, the organelle in which
hematin polymerization takes place. Whether these
bisquinolines meet this criterion is not known. Recent
data17 implies that if differences in bisquinoline ac-
cumulation were to be considered, the correlation be-
tween inhibition of parasite growth and inhibition of
hematin polymerization would likely improve.
N1,N5-Bis(7-ch lor oqu in olin -4-yl)-3-oxa p en ta n e-1,5-d i-
a m in e (1): 1H NMR δ 3.38-3.61 (m, 4H), 3.73 (t, J ) 5.7 Hz,
4H), 6.50 (d, J ) 5.4 Hz, 2H), 7.32 (t, J ) 5.1 Hz, 2H), 7.43
(dd, J ) 9.0, 2.1 Hz, 2H), 7.80 (d, J ) 2.1 Hz, 2H), 8.25 (d, J
) 9.1 Hz, 2H), 8.37 (d, J ) 5.4 Hz, 2H). Anal. (C22H20Cl2N4O)
C, H, N.
N1,N8-Bis(7-ch lor oq u in olin -4-yl)-3,6-d ioxa oct a n e-1,8-
d ia m in e (2): 1H NMR δ 3.41 (dt, J ) 5.6, 5.4 Hz, 4H), 3.58 (s,
4H), 3.66 (t, J ) 5.6 Hz, 4H), 6.47 (d, J ) 5.4 Hz, 2H), 7.32 (t,
J ) 5.4 Hz, 2H), 7.42 (dd, J ) 9.0, 2.2 Hz, 2H), 7.77 (d, J )
2.2 Hz, 2H), 8.24 (d, J ) 9.0 Hz, 2H), 8.37 (d, J ) 5.4 Hz, 2H);
13C NMR δ 42.23, 68.11, 69.74, 98.68, 117.38, 123.94, 123.98,
127.48, 133.32, 149.05, 149.99, 151.79. Anal. (C24H24Cl2N4O2)
C, H, N.
We hypothesize that these bisquinolines, like bis-
quinoline Ro 48-6910 (WR 268,668), inhibit hematin
polymerization by binding to hematin µ-oxo dimer,
shifting the equilibrium between hematin monomer and
hematin µ-oxo dimer, thereby decreasing hematin mono-
mer incorporation into hemozoin.18 However, bisquino-
line-hematin µ-oxo binding may have other conse-
quences which may or may not contribute to their
antimalarial properties. One example is inhibition of
both glutathione- and glutathione/hydrogen peroxide-
mediated iron release from hematin and inhibition of
hematin-dependent lipid peroxidation by bisquinoline
3 as shown by Scott et al.19 Another is inhibition of
polyamine transport20 as was observed for bisquinoline
N1,N4-bis(7-chloroquinolin-4-yl)-1,4-diaminobutane.2
In summary, compared to alkane-bridged bisquino-
lines,2 none of these heteroalkane-bridged bisquinolines
had sufficient antimalarial activity to warrant further
investigation of the series. However one promising
outcome was that 6 of the 11 bisquinolines were
significantly more potent against the chloroquine-
resistant W2 clone compared to the chloroquine-sensi-
tive D6 clone, an unusual occurence for 4-aminoquino-
lines of any type. This work also adds further evidence
to support the hypothesis that bisquinolines inhibit
parasite growth via inhibition of hematin polymeriza-
tion.
N1,N12-Bis(7-ch lor oq u in olin -4-yl)-4,9-d ioxa d od eca n e-
1,12-d ia m in e (3): H NMR δ 1.57 (br s, 4H), 1.77-2.03 (m,
1
4H), 3.18-3.73 (m, 12H), 6.46 (d, J ) 5.5 Hz, 2H), 7.19-7.39
(m, 2H), 7.44 (dd, J ) 9.0, 2.0 Hz, 2H), 7.79 (d J ) 1.8 Hz,
2H), 8.26 (d, J ) 9.0 Hz, 2H), 8.39 (d, J ) 5.3 Hz, 2H); 13C
NMR δ 26.08, 28.21, 39.58, 67.67, 69.90, 98.50, 117.41, 123.96,
127.45, 133.31, 149.04, 150.08, 151.84. Anal. (C28H32Cl2N4O2)
C, H, N.
N1,N13-Bis(7-ch lor oqu in olin -4-yl)-4,7,10-tr ioxatr idecan e-
1
1,13-d ia m in e (4): H NMR δ 1.84-2.11 (m, 4H), 3.16-3.47
(m, 4H), 3.48-3.83 (m, 12H), 5.93-6.15 (m, 2H), 6.31 (d, J )
5.4 Hz, 2H), 7.31 (dd, J ) 9.0, 2.1 Hz, 2H), 7.70 (d, J ) 9.0 Hz,
2H), 7.92 (d, J ) 2.1 Hz, 2H), 8.48 (d, J ) 5.4 Hz, 2H); 13C
NMR δ 28.10, 42.27, 70.31, 70.46, 70.74, 98.60, 117.34, 121.60,
124.95, 128.55, 134.63, 149.09, 150.03, 152.05. Anal. (C28H32
Cl2N4O3) C, H, N.
-
N1,N5-Bis(7-ch lor oq u in olin -4-yl)-2-a za p en t a n e-1,5-d i-
a m in e (5): 1H NMR δ 2.88 (t, J ) 6.3 Hz, 4H), 3.04-3.64 (m,
4H), 6.47 (d, J ) 5.5 Hz, 2H), 7.11-7.35 (m, 2H), 7.39 (dd, J
) 8.9, 2.1 Hz, 2H), 7.77 (d, J ) 2.1 Hz, 2H), 8.20 (d, J ) 9.0
Hz, 2H), 8.36 (d, J ) 5.4 Hz, 2H); 13C NMR δ 42.63, 47.07,
98.70, 117.43, 123.99, 127.50, 133.37, 149.06, 150.15, 151.83.
Anal. (C22H21Cl2N5) C, H, N.
N1,N6-Bis(7-ch lor oq u in olin -4-yl)-3-a za h exa n e-1,6-d i-
a m in e (6): 1H NMR δ 1.78-1.92 (m, 2H), 2.72 (t, J ) 6.5 Hz,
2H), 2.86 (t, J ) 6.5 Hz, 2H), 3.26-3.49 (m, 4H), 6.47 (d, J )
5.6 Hz, 1H), 6.53 (d, J ) 5.5 Hz, 1H), 7.22-7.32 (m, 1H), 7.39
(dd, J ) 9.0, 2.3 Hz, 1H), 7.44 (dd, J ) 9.0, 2.2 Hz, 1H), 7.47-
7.58 (m, 1H), 7.78 (d, J ) 2.2 Hz, 1H), 7.80 (d, J ) 2.2 Hz,
1H), 8.21 (d, J ) 9.0 Hz, 1H), 8.25 (d, J ) 9.1 Hz, 1H), 8.38 (d,
J ) 5.4 Hz, 1H), 8.41 (d, J ) 5.4 Hz, 1H); 13C NMR δ 28.10,
41.00, 42.55, 47.03, 47.38, 98.52, 98.66, 117.41, 123.94, 127.46,
Exp er im en ta l Section
Melting points were taken with a Mel-Temp capillary
apparatus. Except where noted, IR spectra were run as KBr
133.26, 133.32, 149.05, 150.08, 150.13, 151.87. Anal. (C23H23
Cl2N5) C, H, N.
-

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Antimalarial Bisquinolines
J ournal of Medicinal Chemistry, 1998, Vol. 41, No. 22 4363
N1,N5-Bis(7-ch lor oq u in olin -4-yl)-4-a za h ep t a n e-1,7-d i-
a m in e (7): 1H NMR δ 1.72-1.95 (m, 4H), 2.68 (t, J ) 6.5 Hz,
4H), 3.33 (t, J ) 6.5 Hz, 4H), 6.45 (d, J ) 5.5 Hz, 2H), 7.43,
(dd, J ) 9.2, 2.0 Hz, 2H), 7.52 (br s, 2H), 7.79 (d, J ) 2.2 Hz,
2H), 8.23 (d, J ) 9.0 Hz, 2H), 8.38 (d, J ) 5.4 Hz, 2H); 13C
NMR δ 27.97, 41.06, 47.37, 98.53, 117.41, 123.92, 123.94,
127.49, 133.29, 149.05, 150.07, 151.86. Anal. (C24H25Cl2N5)
C, H, N.
N1,N7-Bis(7-ch lor oqu in olin -4-yl)-N4-m eth yl-4-a za h ep -
ta n e-1,7-d ia m in e (8): 1H NMR δ 1.70-1.96 (m, 4H), 2.23 (s,
3H), 2.46 (t, J ) 6.7 Hz, 4H), 3.16-3.40 (m, 4H), 6.40 (d, J )
5.5 Hz, 2H), 7.43 (dd, J ) 9.0, 2.3 Hz, 2H), 7.49 (d, J ) 2.2 Hz,
2H), 8.21 (d, J ) 9.0 Hz, 2H), 8.36 (d, J ) 5.4 Hz, 2H); 13C
NMR δ 25.44, 40.93, 41.86, 55.08, 98.49, 117.41, 123.89,
mated microdilution technique of Desjardins et al.21 and
Milhous et al.22 Two P. falciparum malaria parasite clones,23
designated as Sierra Leone (D6) and Indochina (W2), were
used in susceptibility testing. The former is resistant to
mefloquine and the latter to chloroquine, pyrimethamine,
sulfadoxine, and quinine. Test compounds were dissolved in
dimethyl sulfoxide and solutions serially diluted with culture
media. Erythrocytes with 0.25-0.5% parsitemia were added
to each well of a 96-well microdilution plate to give a final
hematocrit of 1.5%. Inhibition of uptake of tritiated hypox-
anthine was used as an index of antimalarial activity. Results
are reported as IC50 (ng/mL) values.
In vivo activity against P. berghei was obtained against a
drug-sensitive strain of P. berghei (strain KBG 173).24 Each
test compound was administered sc to five male mice per
dilution in a single subcutaneous dose 3 days after infection.
Untreated mice survived on average 6.2 days. Compounds
were classified as curative (C) when one or more test animals
lived 60 days postinfection. Deaths from 0-2 days posttreat-
ment were attributed to toxicity (T).
123.97, 127.48, 133.29, 149.03, 150.05, 151.84. Anal. (C25H27
Cl2N5) C, H, N.
-
N1,N13-Bis(7-ch lor oqu in olin -4-yl)-7-a za tr id eca n e-1,13-
d ia m in e (9). The crude reaction product was purified by
column chromatography using neutral alumina eluting suc-
cessively with 99:1 and then 99:5 CHCl3-CH3OH. Bisquino-
line 9 was collected during elution with the 99:5 solvent
mixture: 1H NMR δ 1.34 (br s, 12H), 1.60-1.67 (m, 4H), 2.42-
2.46 (m, 4H), 3.12-3.27 (m, 4H), 6.44 (d, J ) 5.4 Hz, 2H), 7.29
(t, J ) 5.1 Hz, 2H), 7.44 (dd, J ) 9.0, 2.4 Hz, 2H), 7.78 (d, J )
2.4 Hz, 2H), 8.28 (d, J ) 9.0 Hz, 2H), 8.38 (d, J ) 5.4 Hz, 2H);
13C NMR δ 26.61, 26.67, 27.77, 29.59, 42.36, 49.40, 98.55,
117.43, 123.89, 124.08, 127.45, 133.29, 149.10, 150.05, 151.87.
Anal. (C30H37Cl2N5) C, H, N.
Hem a tin P olym er iza tion Assa y. Hematin polymeriza-
tion experiments were performed as described by Dorn et al.3,4c
with P. falciparum K1 trophozoite acetonitrile extract to
initiate the reaction. Bisquinolines were added to the reaction
mixtures as DMSO solutions up to a maximum DMSO
concentration of 10%. The values of triplicate assays were
plotted semilogarithmically (DeltaGraph Pro 3.5 and CA-
Cricket Graph III 1.5.2) and the IC50 values (µM) calculated
graphically ( SD.
N1-[(7-Ch lor oq u in olin -4-yl)a m in oet h yl]-N4-(7-ch lor o-
qu in olin -4-yl)p ip er a zin e (10): 1H NMR δ 2.70-2.86 (m, 6H),
3.11-3.27 (br s, 4H), 3.40-3.56 (m, 2H), 6.55 (d, J ) 5.5 Hz,
1H), 6.98 (d, J ) 5.1 Hz, 1H), 7.30 (t, J ) 5.1 Hz, 1H), 7.48
(dd, J ) 9.0, 2.2 Hz, 1H), 7.55 (dd, J ) 9.1, 2.1 Hz, 1H), 7.84
(d, J ) 2.2 Hz, 1H), 8.00 (d, J ) 2.2 Hz, 1H), 8.02 (d, J ) 8.8
Hz, 1H), 8.28 (d, J ) 9.1 Hz, 1H), 8.45 (d, J ) 5.4 Hz, 1H),
8.71 (d, J ) 5.0 Hz, 1H); 13C NMR δ 51.78, 52.65, 53.65, 98.76,
109.38, 117.44, 121.36, 123.96, 124.14, 125.72, 126.02, 127.55,
128.07, 133.42, 133.55, 149.08, 149.62, 149.99, 151.97, 152.16,
156.25. Anal. (C24H23Cl2N5‚0.5H2O) C, H, N.
Bis[4-(7-ch lor oq u in olin -4-yl)p ip er a zin -1-yl]m et h a n e
(11). Aqueous formaldehyde (37%) (1.5 mmol, 0.045 g) was
added to a solution of 7-chloro-4-(piperazin-1-yl)quinoline (1.0
mmol, 0.248 g) in MeOH (1 mL) and the mixture stirred for 5
h at room temperature. CHCl3 (15 mL) was added, and the
solution was dried over Na2SO4. Removal of solvent in vacuo
provided a viscous oil which was dissolved in hot CHCl3 (1
mL). To this solution was added CH3N (10 mL) which initiated
crystallization of 11 (0.164 g, 65%) as white needles: 1H NMR
(CDCl3) δ 2.85 (t, J ) 5.4 Hz, 8H), 3.28 (t, J ) 5.4 Hz, 8H),
3.19 (s, 2H), 6.85 (d, J ) 5.4 Hz, 2H), 7.42 (dd, J ) 9.0, 1.8
Hz, 2H), 7.97 (d, J ) 9.0 Hz, 2H), 8.04 (d, J ) 1.8 Hz, 2H),
8.72 (d, J ) 5.4 Hz, 2H); 13C NMR (CDCl3) δ 51.38 (t), 52.24
(t), 80.74 (t), 108.96 (d), 121.97 (s), 125.22 (d), 126.03 (d), 128.90
(d), 134.81 (s), 150.19 (s), 151.92 (d), 157.02 (s). Anal.
(C27H28N6Cl2) C, H, N.
7-Ch lor o-4-(p ip er a zin -1-yl)qu in olin e (12). A solution of
4,7-dichloroquinoline (0.03 mol, 5.94 g) and piperazine (0.3 mol,
25.84 g) in 2-ethoxyethanol (30 mL) was refluxed under Ar
for 24 h. The mixture was cooled and then reheated to distill
off the solvent and excess piperazine. Water (100 mL) and 1
N KOH were added, and the aqueous layer was extracted twice
with 150-mL portions of a 1:1:1 mixture of EtOAc-Et2O-CH2-
Cl2. The combined organic layers were washed with 75 mL of
brine and dried over K2CO3. Solvent removal and prolonged
evacuation under low pressure provided 12 (6.68 g, 90%) as a
pale-yellow crystalline solid. Recrystallization from ether
afforded an off-white crystalline solid: mp 113-115 °C (lit.12
mp 113-115 °C); 1H NMR (CDCl3) δ 3.18 (s, 8H), 6.83 (d, J )
5.4 Hz, 1H), 7.41 (dd, J ) 9.0, 1.8 Hz, 1H), 7.96 (d, J ) 9.0 Hz,
1H), 8.03 (d, J ) 1.8 Hz, 2H), 8.72 (d, J ) 5.4 Hz, 2H); 13C
NMR (CDCl3) δ 46.01, 53.49, 108.85, 121.86, 125.16, 125.97,
128.97, 134.70, 150.08, 151.87, 157.29.
Ack n ow led gm en t. This work was funded in part
by DHHS/NIH/NIAID Grant 1 R15 AI28012-01 to J . L.
Vennerstrom and Army Contract DAMD 17-91-1010 to
A. L. Ager. 3-Azahexane-1,6-diamine, 7-azatridecane-
1,13-diamine, and 4-azaheptane-1,7-diamine samples
were graciously provided by Grace A. Pulci, J eff Weeks,
Sally McCoach, Frank E. Herkes, and Robert Smiley of
E. I. DuPont De Nemours and Co. Inc. Bis(3-aminopro-
pyl)methylamine, 3-azapentane-1,5-diamine, 4,9-dioxa-
dodecane-1,12-diamine, 3-azahexane-1,6-diamine, and
4,7,10-trioxatridecane-1,13-diamine were graciously pro-
vided by Gordon Ross, J ohn Banger, and Robert J . Steffl
of BASF Corp. N-Aminoethylpiperazine and 3,6-diox-
aoctane-1,8-diamine were graciously provided by Gor-
don Neville, Howard P. Klein, and Phillip B. Valkovich
of Texaco Chemical Co.
Refer en ces
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