Synthesis and in vitro antitumor activity of new quinoxaline derivatives

Article abstract of DOI:10.1016/j.ejmech.2008.07.025

A series of novel 5,7-diamino-3-phenyl-2-benzylamino, 2-phenoxy, and 2-thiophenyl substituted quinoxalines has been designed, synthesized and evaluated for their in vitro antitumor activity towards cell lines of nine different types of human cancers. Some

Full text of DOI:10.1016/j.ejmech.2008.07.025

European Journal of Medicinal Chemistry 44 (2009) 1579–1591
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis and in vitro antitumor activity of new quinoxaline derivatives
*
Paola Corona , Antonio Carta, Mario Loriga, Gabriella Vitale, Giuseppe Paglietti
`
Dipartimento Farmaco Chimico Tossicologico, Universita degli Studi di Sassari, Via Muroni 23/A, 07100 Sassari, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 3 April 2008
Received in revised form 14 July 2008
Accepted 17 July 2008
Available online 26 July 2008
A
series of novel 5,7-diamino-3-phenyl-2-benzylamino, 2-phenoxy, and 2-thiophenyl substituted
quinoxalines has been designed, synthesized and evaluated for their in vitro antitumor activity towards
cell lines of nine different types of human cancers. Some of these compounds exhibited inhibitory
effects on the growth of a wide range of cancer cell lines generally at 10ꢀ6 M, in some cases at 10ꢀ7 M and
10ꢀ8 M concentrations. Within this series the benzylamino quinoxaline derivatives 1b–7b were the most
active, whereas compound 2c showed the highest MG_MD value (ꢀ5.66).
Keywords:
Ó 2008 Elsevier Masson SAS. All rights reserved.
5,7-Diamino-3-phenyl-2-benzylamino,
2-phenoxy and 2-phenylthio substituted
quinoxalines
Antitumor activity
1. Introduction
and ovarian cancer [33]. In this series compounds 2a and 4a,
possessing the 3,5-dimethoxyanilino and 3,4,5-trimethoxyanilino,
Cancer is the second leading cause of death in industrialized
countries. Although an upsurge in the search for new antitumor
agents has recently been observed, the survival rate of patients
still remains low. One of the reasons is the poor sensitivity of
tumours to drugs. Therefore, major progress in chemotherapy
would require new and useful antitumor agents to eradicate the
entire range of cancer diseases in the world over. New
compounds can be identified by a wide variety of approaches
from empirical screening to rational design [1,2]. Many synthetic
small molecules derived from different groups of heterocycles
with influence on carcinogenesis have been reported and
several of them are currently in clinical trials [3,4]. Quinoxalines
have shown a broad spectrum of biological activities such as
antibacterial [5], antiviral [6], herbicidal [7] and anti-inflam-
matory activity [8,9], hence they are an important class of
nitrogen-containing heterocycles and useful intermediates in
organic synthesis [10,11]. Recently some of this type of mole-
cules have been reported as candidates for the treatment of
cancer and disorders associated with angiogenesis functions
[12–17].
respectively, moiety at 2-position of the quinoxaline ring, were the
most active as they showed growth inhibitory activity at nanomolar
concentrations against both leukemia CCRF-CEM and ovarian
cancer OVCAR-4 cell lines. In the light of these results and in order
to further explore the structure–activity relationships for this class
of compounds, in the present study we synthesized a new series
of 5,7-diamino-3-phenylquinoxalin-2-yl substituted derivatives
depicted in Fig. 2. The antitumor activity of all new compounds was
preliminarily evaluated on three human tumor cell lines according
to the protocols available at the National Cancer Institute (NCI,
Bethesda, MD), and successively the active compounds were tested
on the whole panel of 60 tumor cell lines.
2. Results and discussion
2.1. Chemistry
The synthetic routes to obtain the designed compounds 1b–7b,
c and 1d–5d (Fig. 2) and their intermediates are described in
Scheme 1. 5,7-Dinitro-3-phenyl-2-chloroquinoxaline (8), synthe-
sized as previously reported by us [33], underwent nucleophilic
attack by the corresponding benzylamines 9–13, phenols 14, 16–21,
thiophenols 23–26 and esters 15 [34], 22 [35], 45 [36,37] to give
both the 5,7-dinitrosubstituted quinoxalines 27–44 and 46. The
desired 5,7-diamino-3-phenylquinoxalines 1b–3b, 5b–7b, 1c–5c,
7c, 1d–5d were obtained by reduction with an excess of hydrazine
hydrate in ethanol and in presence of 10% palladised charcoal or by
catalytic hydrogenation with hydrogen and 10% palladised charcoal
(4b, 6c).
Our continuous interest in the synthesis of new quinoxalines
derivatives as potential antitumor agents [18–33] led to the
discovery of the 5,7-diamino-3-phenyl-2-anilino substituted qui-
noxalines 1–7a (Fig. 1), which exhibited potent activity against
some cell lines of leukemia, CNS cancer, melanoma, renal cancer
* Corresponding author. Tel.: þ39 079228764; fax: þ39 079228720.
E-mail address: pcorona@uniss.it (P. Corona).
0223-5234/$ – see front matter Ó 2008 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2008.07.025

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P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
determinations were made with alamar blue. Results for each
NH2
compound were reported as the percent of growth of the treated
cells compared to the untreated control cells (Table 1). For the NCI
criteria, compounds which reduce the growth of anyone of the
cancer cell lines to ca. 32% or less (negative numbers indicate cell
kill) are identified as ‘active’ and subsequently are evaluated in
a full panel of 60 cell lines over a 5-log dose range. The diamino-
quinoxalines 1b–7b, 1c, 2c, 5c, 6c, 1d, 3d, 4d matched these criteria
and were evaluated for their anti-cancer activity following the
known in vitro disease-oriented antitumor screening program
which is based upon the use of a multiple panel of 60 human tumor
cell lines [38,39]. A 48 h drug exposure protocol was used and
a sulforhodamine B (SRB) protein assay was employed to estimate
cell viability or growth [40]. Moreover, based upon the data of anti-
cancer activities of 7b, two more compounds (7c and 5d) with the
same benzoyl glutamic moiety were included for evaluation against
the full panel of 60 tumor cell lines. The anti-cancer activity of
a tested compound is given by three parameters for each cell line:
log10 GI50 value (GI50 ¼ molar concentration of the compound that
inhibits 50% net cell growth), log10 TGI value (TGI ¼ molar
concentration of the compound leading to total inhibition of net
cell growth), and log10 LC50 value (LC50 ¼ molar concentration of
the compound leading to 50% net cell death). Furthermore, a mean
graph midpoint (MG_MID) is calculated for each of the mentioned
parameters, giving an averaged activity of each compound deduced
from dose–response curves. For the calculation of the MG_MID,
insensitive cell lines are included with the highest concentration
tested [41–43]. Selectivity of the compound with respect to one or
N
N
H2N
NH
R1
R
R2
1a: R = R2 = H; R1 = OCH3
2a: R = R2 = OCH3; R1 = H
3a: R = R1= OCH3; R2 = H
4a: R = R1 = R2 = OCH3
5a: R= R1 = Cl; R2 = H
6a: R = R2 = H; R1 = F
7a: R = R2 = H; R1 = CO-Glu-Et
Fig. 1. Chemical structure of the series of quinoxalines previously described [33].
2.2. Biology
Evaluation of anti-cancer activity for the diamino-quinoxalines
1b–7b, c and 1d–5d, described in this paper, was performed at the
National Cancer Institute (NCI), Bethesda, MD. First, all compounds
were evaluated in the three-cell line panel consisting of NCI-H460
(Lung), MCF-7 (Breast), and SF-268 (CNS) cell lines. In the assay
protocol, each cell line was inoculated and preincubated on
a microtiter plate. Test agents were added in a single concentration
(10ꢀ4 M) and the culture was incubated for 48 h. End-point
more cell lines of the screen is characterized by a high deviation (D)
of the particular cell line parameter compared to the MG_MID
value.
The log10 GI50, log10 TGI and log10 LC50 values provided by NCI
for compounds 1b–7b, 1c, 2c, 5c–7c, 1d, 3d–5d are reported in
Tables 2 and 3. From the analysis of the values of anti-cancer
activity it is evident that most compounds were active against the
60 human tumor cell lines and showed inhibitory activities at sub-
micromolar concentrations. The aminobenzyl quinoxalines 2b–6b
and the phenoxy derivative 2c proved to be the most active within
the series, showing both potent and broad spectrum of antitumor
activity (MG_MID log GI50 values ranged from ꢀ5.01 to ꢀ5.66).
Compounds 7b, 1c, 5c–7c, 1d, 3d–5d exhibited a moderate to high
selectivity towards one or more tumor cell lines. The 5,7-diamino-
3-phenyl-2-[(3,5-dimethoxy)phenoxy]quinoxaline (2c) was the
most active in the series showing high cytostatic activity on all 60
human tumor cell lines (MG_MID log GI50 value ꢀ5.66), remark-
able anti-cancer activity has been observed against non-small cell
lung cancer NCI-H522 (log GI50 value ꢀ6.05), CNS cancer SNB-75
(log GI50 value ꢀ6.90), melanoma MALME-3M (log GI50 ꢀ6.37),
breast cancer MDA-MB-435 (log GI50 ꢀ6.41) and MDA-N (log GI50
ꢀ6.12). The 5,7-diamino-3-phenyl-2-[(3,5-dimethoxy-benzyl)ami-
no]quinoxaline (2b) exhibited high sensitivity against ovarian
cancer OVCAR-4 (log GI50 value ꢀ7.85). Introduction of one or
more methoxy groups into the aminobenzyl or into the phenoxy
groups induced a significant antiproliferative activity. In fact
compounds 1b, 2b, 3b and 4b showed log MG_MID values of
ꢀ4.87, ꢀ5.23, ꢀ5.01, ꢀ5.42, respectively, and compound 2c was
more potent than 1c (log MG_MID values ꢀ5.66 and ꢀ4.51).
Significantly, the 5,7-diamino-3-phenyl-2-[(3,4,5-trimethoxy-ben-
zyl)amino]quinoxaline (4b) exhibited high sensitivity against
several leukemia RPMI-8226, SR (log GI50 value ꢀ6.16, ꢀ6.05),
colon cancer KM 12 (log GI50 value ꢀ6.32), CNS cancer SNB-75 (log
GI50 value ꢀ6.09), melanoma SK-MEL-5 (log GI50 value ꢀ6.14) and
breast cancer MDA-MB-435 (log GI50 value ꢀ6.64) cell lines.
Compound 5b, which bears two chlorine atoms at 3- and 4-posi-
tion on the benzyl ring, showed good cytotoxic activities against all
leukemia cell lines, especially on CCRF-CEM (log GI50 value ꢀ6.88)
NH2
NH2
N
N
N
N
O
H2N
NH
H2N
R2
R1
R
R2
R
R1
1b: R = R2 = H; R1 = OCH3
2b: R = R2 = OCH3; R1 = H
3b: R = R1 = OCH3; R2 = H
4b: R = R1 = R2 = OCH3
5b: R = R1 = Cl; R2 = H
6b: R = R2 = H; R1 = F
1c: R = R2 = H; R1 = OCH3
2c: R = R2 = OCH3; R1 = H
3c: R = R1 = OCH3; R2 = H
4c: R = R1 = R2 = OCH3
5c: R = R1 = Cl; R2 = H
6c: R = R2 = H; R1 = F
7c: R = R2= H; R1 = CO-Glu-Et
7b: R = R2 = H; R1 = CO-Glu-Et
NH2
N
N
H2N
S
R
R2
R1
1d: R = R2 = H; R1 = OCH3
2d: R = R1 = OCH3; R2 = H
3d: R = R1=Cl; R2 = H
4d: R = R2 = H; R1=F
5d: R = R2 = H; R1 = CO-Glu-Et
Fig. 2. Designed compounds 1–7b, c and 1–5d.

P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
1581
S
O
H3CH2COOC
N
H
v
COOCH2CH3
-
S
2
45
O
N
H3CH2COOC
H
COOCH2CH3
+
Compounds
X
R
R
R
NO2
R2
R
NO2
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
-NH-CH
-NH-CH
-NH-CH
-NH-CH
-NH-CH
-NH-CH
-NH-CH
O
O
O
O
O
O
O
S
OCH
H
OCH
OCH
Cl
F
COGluEt
OCH
H
OCH
OCH
Cl
F
CO-Glu-Et
OCH
OCH
Cl
H
H
OCH
H
OCH
H
H
H
H
OCH
H
N
N
Ph
+
N
N
Ph
X
i for 27-32
OCH
OCH
OCH
Cl
H
X
R1
ii for 33, 34, 36-39, 41-44
iii for 35,40
O2N
Cl
O2N
8
9-26
H
H
OCH
OCH
OCH
Cl
H
H
H
OCH
Cl
H
R
R2
iii
R1
iv
OCH
27-44
H
H
H
H
H
H
H
NO2
vifor 4b, 6c
S
S
S
N
CO-Glu-Et
Ph
S
F
NH2
N
O2N
N
Ph
46
N
H2N
X
iv
R
R2
NH2
R1
N
N
Ph
S
CO-Glu-Et
1-7b,c
1-4d
H2N
5d
Scheme 1. Synthesis of 1–7b, c and 1–5d. Reagents and conditions: (i) 1-propanol, reflux for 30 min to 168 h. (ii) DMF anhydrous, Cs2CO3, 70 ꢁC for 30 min to 6 h. (iii) DMF
anhydrous, N2, Cs2CO3, room temperature for 1 h to 9 h and 45 min. (iv) NH2–NH2$H2O, reflux for 10 min to 6 h. (v) Ethanol, N2, NaBH4, room temperature for 30 min. (vi) H2, 10%
Pd/C, EtOH.
and its counterpart derivative 5c, which has one oxygen atom
between the quinoxaline scaffold and the phenyl ring, displayed
lower cytotoxicity against the same cell lines, accompanied with
higher cytotoxicity against renal cancer A498 cell line (log GI50
value ꢀ6.35). Among all of these compounds 7b and 5d displayed
3,5-dimethoxy phenyl moiety in analogy with 2a (Fig. 1), which is
the most active of the series described [33]. The results of this
investigation prompt us to continue the development and testing of
novel diamino quinoxaline derivatives and to carry out further
studies to investigate SAR and their mechanisms of action.
a moderate to high selectivity towards leukemia cell lines (Dlog
GI50 ranged from 1.38 to 3.12; Table 4), particularly remarkable is
the considerable antiproliferative activity of 5d against leukemia
K-562 (log GI50 value less than ꢀ8.00).
4. Experimental
4.1. Chemistry
3. Conclusion
4.1.1. General remarks
Melting points were carried out with a Ko¨fler hot stage or Digital
Electrothermal melting point apparatus and are uncorrected.
Infrared spectra were recorded as nujol mulls on NaCl plates with
In summary, we have synthesized a series of 5,7-diamino-3-
phenyl-2-benzylamino, 2-phenoxy and 2-phenylthio substituted
quinoxalines. Some of these had excellent growth inhibition
activity against most of the cancer cell lines tested. Among the
examined series the 5,7-diamino-3-phenyl-2-benzylamino qui-
noxaline derivatives 1b–6b exhibited better anti-cancer activity
than the corresponding 5,7-diamino-3-phenyl-2-anylino 1a–7a
analogues previously described [33] (Table 5). Introduction of two
or more methoxy groups on the phenyl side chain at 2-position of
quinoxaline ring produces a favourable effect on the anti-cancer
activity on the whole as well as the presence of fluorine and
chlorine atoms. Compound 2c shows the best antiproliferative
profile of all the series reported (MG_MD value 5.66). It posses
a Perkin–Elmer 781 IR spectrophotometer and are expressed in
n
(cmꢀ1). UV spectra are qualitative and were recorded in nanometer
(nm) for solutions in EtOH with a Perkin–Elmer Lambda 5 spec-
trophotometer. Nuclear magnetic resonance (1H NMR) spectra
were determined in CDCl3, DMSO-d6, CDCl3/DMSO-d6 (1:3 ratio)
and were recorded with a Varian XL-200 (200 MHz) spectrometer.
Chemical shifts (d scale) are reported in parts per million (ppm)
downfield from tetramethylsilane (TMS) used as internal standard.
Splitting patterns are designated, as follows: s, singlet; d, doublet; t,
triplet; q, quadruplet; m, multiplet; br s, broad singlet; dd, double
doublet.

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P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
Table 1
4.1.2.1.2. 5,7-Dinitro-3-phenyl-2-[(3,5-dimethoxy-benzyl)amino]-
quinoxaline (28). This compound was obtained in 95% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol) and 3,5-dimethoxy-benzylamine (10)
(226 mg,1.35 mmol) for 30 min; m.p.178–179 ꢁC (from C2H6O); TLC
Primary assay results for anti-cancer activity of diamino-quinoxalines 1–7b, c and
1–5d
Compound
R
R1
R2
Growth percentage at 10ꢀ4 M
concentration cancer cell line
NCI-H460
(lung)
MCF-7
(breast)
SF-268
(CNS)
(petroleum ether/ethyl acetate 7:3): Rf 0.42; IR (nujol):
1535, 1345 cmꢀ1; UV (EtOH): lmax 402, 285, 244 nm; 1H NMR
(CDCl3):
7.90–7.80 (2H, m, Ar), 7.61–7.50 (3H, m, Ar), 6.49 (2H, d, J ¼ 2.2 Hz,
Ar), 6.39 (1H, t, Ar), 6.07 (1H, t, exc. with D2O, NH), 4.74 (2H, d, CH2),
3.78 (6H, s, 2 ꢃ CH3). GC/MS: m/z 461 [M]þ. Anal. Calcd. for
C23H19N5O6: C, 59.87; H, 4.15; N, 15.18; found C, 60.23; H, 4.15; N,
15.00.
4.1.2.1.3. 5,7-Dinitro-3-phenyl-2-[(3,4-dimethoxy-benzyl)amino]-
quinoxaline (29) [44]. This compound was obtained in 90% yield by
the protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol) and 3,4-dimethoxy-benzylamine (11)
(226 mg, 1.35 mmol) for 30 min; m.p. 190–191 ꢁC (from C2H6O);
n 3440, 1610,
1b
2b
3b
4b
5b
6b
7b
1c
2c
3c
4c
5c
6c
7c
1d
2d
3d
4d
5d
H
OCH3
H
OCH3
OCH3
Cl
F
CO–Glu–Et
OCH3
H
OCH3
OCH3
Cl
F
H
OCH3
H
OCH3
H
H
H
H
OCH3
H
OCH3
H
H
H
H
H
H
H
H
0
ꢀ1
3
7
0
0
ꢀ72
0
0
0
0
ꢀ28
47
15
0
d
8.74 (1H, d, J ¼ 2.6 Hz, H-6), 8.46 (1H, d, J ¼ 2.6 Hz, H-8),
OCH3
OCH3
OCH3
Cl
H
H
1
1
2
1
97
ꢀ48
2
118
N.t.a
0
0
73
0
79
ꢀ56
1
131
N.t.a
0
6
75
7
H
ꢀ89
OCH3
OCH3
OCH3
Cl
H
H
H
OCH3
Cl
H
H
0
117
N.t.a
2
2
42
8
121
12
7
CO–Glu–Et
OCH3
OCH3
Cl
TLC (petroleum ether/ethyl acetate 8:2): Rf 0.39; IR (nujol):
n 3420,
1590, 1525, 1350 cmꢀ1 1H NMR (CDCl3):
;
d
8.76 (1H, d, J ¼ 2.4 Hz,
119
0
0
136
11
0
Ar), 8.49 (1H, d, J ¼ 2.4 Hz, Ar), 7.88–7.80 (2H, m, Ar) 7.60–7.52 (3H,
F
m, Ar), 6.98–6.81 (3H, m, Ar), 6.02 (1H, t, exc. with D2O, NH), 4.73
CO–Glu–Et
97
65
42
(2H, d, CH2), 3.88 (6H, s, 2 ꢃ CH3). 13C NMR (CDCl3):
d 43.2 (CH2), 56
a
Not tested.
(2 ꢃ CH3), 109.3 (CH), 112.4 (CH), 115 (CH), 120 (CH), 126.2 (CH),
127.3 (2 ꢃ CH), 128.5 (CH), 129.3 (2 ꢃ CH), 130 (C), 133.5 (C), 135.2
(C), 138.1 (C), 141.3 (C), 143 (C), 147.6 (C), 148 (C), 149.6 (C), 154.5 (C).
GC/MS: m/z 461 [M]þ. Anal. Calcd. for C23H19N5O6: C, 59.87; H, 4.15;
N, 15.18; found C, 59.76; H, 4.04; N, 14.97.
The assignment of exchangeable protons (OH and NH) was
confirmed by the addition of D2O. Ms spectra were performed on
combined HP 5790-HP 5970 GC/MS apparatus or with a combined
Liquid Chromatograph-Agilent 1100 series Mass Selective Detector
(MSD). Analyticalthin-layerchromatography(TLC)wasperformedon
Merck silicagel F-254plates. Pure compoundsshowed a single spot in
TLC. For flash chromatography, Merck silica gel 60 was used with
a particle size 0.040–0.063 mm (230–400 mesh ASTM). Elemental
analysis was performed on a Perkin–Elmer 2400 instrument at
4.1.2.1.4. 5,7-Dinitro-3-phenyl-2-[(3,4,5-trimethoxy-benzyl)amin
o]quinoxaline (30). This compound was obtained in 95% yield by
the protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol) and 3,4,5-trimethoxy-benzylamine (12)
(266 mg, 1.35 mmol) for 1 h; m.p. 101–102 ꢁC (from C2H6O); TLC
(petroleum ether/ethyl acetate 6:4): Rf 0.35; IR (nujol):
1590, 1535, 1345 cmꢀ1; UV (EtOH): lmax 400, 286, 245 nm; 1H NMR
(CDCl3):
n 3420,
`
Laboratorio di Microanalisi, Dipartimento di Chimica, Universita di
Sassari, Italy, and the results were within ꢂ0.4% of theoretical values.
d
8.76 (1H, d, J ¼ 2.6 Hz, H-6), 8.48 (1H, d, J ¼ 2.6 Hz, H-8),
7.90–7.80 (2H, m, Ar), 7.65–7.55 (3H, m, Ar), 6.60 (2H, s, Ar), 6.04
(1H, t, exc. with D2O, NH), 4.73 (2H, d, CH2), 3.85 (6H, s, 2 ꢃ CH3),
3.84 (3H, s, CH3). GC/MS: m/z 491 [M]þ. Anal. Calcd. for
C24H21N5O7: C, 58.65; H, 4.31; N, 14.25; found C, 58.58; H, 4.00; N,
14.01.
4.1.2. Intermediates
The intermediate chloroquinoxaline (8) has been prepared as
described by us in a recent paper [33]. The esters N-[4(amino-
methyl)benzoyl]glutamic acid diethyl ester [34] (15), N-[4-
(hydroxy)benzoyl]glutamic acid diethyl ester (22) [35] and
tetraethyl 4,40-dithiobis(N-benzoyl-
L-glutamate) (45) [36,37] are
not commercially available and were obtained according to the
procedure described in the cited literature.
4.1.2.1.5. 5,7-Dinitro-3-phenyl-2-[(3,4-dichloro-benzyl)amino]qui
noxaline (31). This compound was obtained in 86% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol) and 3,4-dichlorobenzylamine (13) (238 mg,
1.35 mmol) for 1 h and 50 min; m.p. 217–218 ꢁC (from C2H6O); TLC
4.1.2.1. General procedure for preparation of 5,7-dinitro-3-phenyl-2-
aminobenzyl substituted quinoxalines (27–33). A solution of 8
(150 mg, 0.45 mmol) in 1-propanol (15 mL) was obtained by
heating under reflux. Then to this solution an excess of either the
required substituted benzylamines (9–14) or the ester (15) [34] was
added. Heating was maintained for different times as reported
below. After cooling, the formed coloured precipitates were filtered
off to give the desired aminobenzyl quinoxalines.
(petroleum ether/ethyl acetate 8:2): Rf 0.53; IR (nujol):
1595, 1525, 1350 cmꢀ1; UV (EtOH): lmax 400, 283, 242 nm; 1H NMR
(CDCl3):
8.00 (1H, t, exc. with D2O, NH), 7.87 (2H, dd, J ¼ 6.2 Hz and
J ¼ 2.4 Hz, Ar), 7.66–7.54 (3H, m, Ar), 7.46–7.35 (3H, m, Ar), 4.71 (2H,
d, CH2). GC/MS: m/z 469 [M]þ. Anal. Calcd. for C21H13Cl2N5O4: C,
59.63; H, 2.79; N, 14.89; found C, 59.40; H, 2.55; N, 14.75.
4.1.2.1.6. 5,7-Dinitro-3-phenyl-2-[(4-fluoro-benzyl)amino]quinox
aline (32). This compound was obtained in 89% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol) and 4-fluoro-benzylamine (14) (169 mg,
1.35 mmol) for 1 h and 30 min; m.p. 213–214 ꢁC (from C2H6O); TLC
n 3390,
d
8.61 (1H, d, J ¼ 2.6 Hz, H-6), 8.41 (1H, d, J ¼ 2.6 Hz, H-8),
4.1.2.1.1. 5,7-Dinitro-3-phenyl-2-[(4-methoxy-benzyl)amino]quin
oxaline (27). This compound was obtained in 95% yield by the
protocol described in the general procedure starting from 8 (150 mg,
0.45 mmol) and 4-methoxy-benzylamine (9) (185 mg, 1.35 mmol)
for 1 h; m.p. 201–202 ꢁC (from CH3CN); TLC (petroleum ether/ethyl
(petroleum ether/ethyl acetate 7:3): Rf 0.53; IR (nujol):
1605, 1520, 1350 cmꢀ1; UV (EtOH): lmax 415, 302, 260, 204 nm; 1H
NMR (CDCl3/DMSO-d6):
n 3490,
acetate 8:2): Rf 0.35; IR (nujol):
n
3380, 1610, 1530, 1345 cmꢀ1; UV
8.75 (1H, d,
(EtOH): lmax 403, 287, 247, 210 nm; 1H NMR (CDCl3):
d
d
8.75 (1H, d, J ¼ 2.6 Hz, H-6), 8.48 (1H, d,
J ¼ 2.6 Hz, H-6), 8.46 (1H, J ¼ 2.4 Hz, H-8), 7.89–7.79 (2H, m, Ar),
7.61–7.52 (3H, m, Ar), 7.31 (2H, d, J ¼ 8.6 Hz, Ar), 6.89 (2H, d,
J ¼ 8.6 Hz, Ar), 6.04 (1H, t, exc. with D2O, NH), 4.73 (2H, d, CH2), 3.80
(3H, s, CH3). GC/MS: m/z 431 [M]þ. Anal. Calcd. for C22H17N5O5: C,
61.25; H, 3.97; N, 16.23; found C, 61.15; H, 3.84; N, 16.11.
J ¼ 2.6 Hz, H-8), 7.82 (2H, dd, J ¼ 6.2 Hz and J ¼ 2.4 Hz, Ar), 7.65–7.55
(3H, m, Ar), 7.42–7.32 (2H, m, Ar), 7.12–7.02 (2H, m, Ar), 6.08 (1H, t,
exc. with D2O, NH), 4.77 (2H, d, CH2). GC/MS: m/z 419 [M]þ. Anal.
Calcd. for C21H14FN5O4: C, 60.14; H, 3.36; N, 16.70; found C, 60.00;
H, 3.13; N, 16.45.

Table 2
Inhibition of in vitro cancer lines by selected 5,7-diamino-3-phenyl-2-anylino-quinoxalines, 1–7b, 1ca
Cell lines
Respnse parameters: (A) log GI50b [M], (B) log TGIc [M], (C) log LC50d [M]
1b
2b
3b
4b
5b
6b
7b
1c
A
B
C
A
B
C
A
B
C
A
B
–
C
–
A
B
C
A
B
–
C
–
A
B
C
A
B
C
Leukemia
CCRF-CEM
HL-60(TB)
K-562
RPMI-8226
SR
ꢀ5.47 ꢀ4.19 >ꢀ4.00 ꢀ5.76 ꢀ5.25 >ꢀ4.00
ꢀ4.87 ꢀ4.29 >ꢀ4.00 ꢀ5.42 >ꢀ4.00 >ꢀ4.00
ꢀ4.60 ꢀ4.01 >ꢀ4.00 ꢀ5.44 ꢀ5.03 >ꢀ4.00
ꢀ5.38 ꢀ4.80 >ꢀ4.00 ꢀ5.66 ꢀ5.21 >ꢀ4.00
ꢀ5.39 >ꢀ4.00 >ꢀ4.00 ꢀ5.42 >ꢀ4.00 >ꢀ4.00
ꢀ5.46 ꢀ4.15 >ꢀ4.00 –
ꢀ6.88 ꢀ5.74 ꢀ4.76
–
ꢀ4.64 >ꢀ4.00 >ꢀ4.00 ꢀ5.53 ꢀ4.90 >ꢀ4.00
ꢀ4.81 >ꢀ4.00 >ꢀ4.00
ꢀ5.22 >ꢀ4.00 >ꢀ4.00 ꢀ5.75 >ꢀ4.30 >ꢀ4.30 ꢀ5.51 ꢀ4.75 >ꢀ4.00 ꢀ5.36 >ꢀ4.00 >ꢀ4.00 ꢀ5.06 >ꢀ4.00 >ꢀ4.00 ꢀ4.58 >ꢀ4.00 >ꢀ4.00
ꢀ5.50 ꢀ4.09 >ꢀ4.00 ꢀ5.90 >ꢀ4.30 >ꢀ4.30 ꢀ5.74 ꢀ5.10 >ꢀ4.00
5.41 >ꢀ4.00 >ꢀ4.00 ꢀ5.64 ꢀ4.69 ꢀ4.17
ꢀ5.67 ꢀ5.14 >ꢀ4.00 ꢀ6.16
ꢀ5.52 >ꢀ4.30 ꢀ5.78 ꢀ5.43 ꢀ5.08 ꢀ5.60 ꢀ5.20 >ꢀ4.00 ꢀ4.55 >ꢀ4.00 >ꢀ4.00 ꢀ4.98 ꢀ4.15 >ꢀ4.00
ꢀ5.48 ꢀ4.74 >ꢀ4.00 ꢀ6.05 >ꢀ4.30 >ꢀ4.30 ꢀ5.79 ꢀ5.22 >ꢀ4.00 ꢀ5.39 >ꢀ4.00 >ꢀ4.00 ꢀ6.30 ꢀ5.24 ꢀ4.03 ꢀ4.73 >ꢀ4.00 >ꢀ4.00
ꢀ5.46 >ꢀ4.00 >ꢀ4.00 ꢀ4.91 >ꢀ4.30 >ꢀ4.30 ꢀ5.68 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ5.74 ꢀ5.01 ꢀ4.46 ꢀ5.27 ꢀ4.03 >ꢀ4.00
MOLT-4
–
–
–
ꢀ5.52 >ꢀ4.00 >ꢀ4.00
Non-small cell lung cancer
A549/ATCC
EKVX
HOP-62
ꢀ4.67 ꢀ4.22 >ꢀ4.00 ꢀ4.48 >ꢀ4.00 >ꢀ4.00
ꢀ4.83 ꢀ4.55 ꢀ4.27 ꢀ5.55 ꢀ5.05 >ꢀ4.00
ꢀ4.76 ꢀ4.46 ꢀ4.16 ꢀ4.87 ꢀ4.50 ꢀ4.14
ꢀ4.89 ꢀ4.43 >ꢀ4.00 ꢀ5.94 ꢀ5.48 ꢀ5.02
ꢀ4.68 ꢀ4.30 >ꢀ4.00 ꢀ5.37 ꢀ4.48 >ꢀ4.30 ꢀ4.97 ꢀ4.56 ꢀ4.16
ꢀ4.75 ꢀ4.46 ꢀ4.16 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.43 >ꢀ4.00 >ꢀ4.00
ꢀ5.23 ꢀ4.52 >ꢀ4.00 ꢀ5.71 ꢀ5.08 ꢀ4.56 ꢀ4.96 ꢀ4.41 >ꢀ4.00 ꢀ5.72 ꢀ5.39 ꢀ5.06 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.61 ꢀ4.20 >ꢀ4.00
ꢀ4.74 ꢀ4.46 ꢀ4.19
ꢀ4.87 ꢀ4.53 ꢀ4.18
ꢀ4.84 ꢀ4.51 ꢀ4.19
ꢀ4.77 >ꢀ4.30 >ꢀ4.30 ꢀ4.80 ꢀ4.50 ꢀ4.19
ꢀ5.92 ꢀ5.51 >ꢀ4.30
ꢀ5.00 ꢀ4.65 >ꢀ4.30 ꢀ4.65 ꢀ4.33 ꢀ4.02 ꢀ4.65 ꢀ4.32 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 –
ꢀ4.41 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.71 ꢀ4.39 ꢀ4.06
HOP-92
–
–
–
ꢀ5.48 ꢀ5.16 >ꢀ4.00 ꢀ4.04 >ꢀ4.00 >ꢀ4.00 –
ꢀ5.09 ꢀ4.11
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
ꢀ4.69 ꢀ4.15 >ꢀ4.00 –
–
–
–
–
ꢀ4.77 ꢀ4.46 ꢀ4.15 ꢀ4.79 >ꢀ4.00 >ꢀ4.00
ꢀ4.64 ꢀ4.28 >ꢀ4.00 ꢀ4.35 >ꢀ4.00 >ꢀ4.00
ꢀ4.69 ꢀ4.32 >ꢀ4.00 ꢀ4.98 >ꢀ4.00 >ꢀ4.00
ꢀ5.00 ꢀ4.66 ꢀ4.32 ꢀ5.54 ꢀ4.64 >ꢀ4.00
ꢀ4.77 ꢀ4.40 ꢀ4.04 ꢀ5.06 ꢀ4.77 ꢀ4.47 ꢀ4.85 ꢀ4.56 ꢀ4.26 ꢀ5.62 ꢀ5.34 ꢀ5.05 ꢀ4.34 >ꢀ4.00 >ꢀ4.00 ꢀ4.60 >ꢀ4.00 >ꢀ4.00
ꢀ4.64 ꢀ4.32 ꢀ4.00 ꢀ5.52 ꢀ4.80 >ꢀ4.30 ꢀ4.87 ꢀ4.52 ꢀ4.16
ꢀ5.46 ꢀ4.94 ꢀ4.39 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00
ꢀ4.62 ꢀ4.04 >ꢀ4.00 ꢀ5.82 >ꢀ4.30 >ꢀ4.30 ꢀ4.68 ꢀ4.33 >ꢀ4.00 ꢀ5.39 ꢀ4.59 >ꢀ4.00 ꢀ4.50 >ꢀ4.00 >ꢀ4.00 ꢀ4.51 >ꢀ4.00 >ꢀ4.00
ꢀ5.57 ꢀ5.20 ꢀ4.20 >ꢀ4.30 >ꢀ4.30 >ꢀ4.30 ꢀ5.69 ꢀ5.31 ꢀ4.65 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.57 >ꢀ4.00 >ꢀ4.00 ꢀ4.50 >ꢀ4.00 >ꢀ4.00
Colon cancer
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
ꢀ4.81 ꢀ4.47 ꢀ4.13 ꢀ5.62 ꢀ5.22 >ꢀ4.00
ꢀ5.10 >ꢀ4.00 >ꢀ4.00 ꢀ5.42 >ꢀ4.30 >ꢀ4.30 ꢀ4.77 ꢀ4.47 ꢀ4.18
ꢀ5.60 ꢀ5.21 >ꢀ4.00 ꢀ4.71 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00
>ꢀ4.00 >ꢀ4.00 >ꢀ4.00 –
ꢀ5.01 ꢀ4.72 ꢀ4.43 ꢀ4.94 ꢀ4.62 ꢀ4.30 ꢀ4.89 >ꢀ4.00 >ꢀ4.00 ꢀ4.04 >ꢀ4.00 >ꢀ4.00 ꢀ4.54 ꢀ4.12 >ꢀ4.00
ꢀ4.52 >ꢀ4.00 >ꢀ4.00 ꢀ5.49 ꢀ4.86 >ꢀ4.30 ꢀ5.33 >ꢀ4.00 >ꢀ4.00 ꢀ5.48 ꢀ4.72 >ꢀ4.00 ꢀ4.32 >ꢀ4.00 >ꢀ4.00 ꢀ4.28 >ꢀ4.00 >ꢀ4.00
ꢀ5.73 ꢀ4.61 >ꢀ4.00 ꢀ5.06 ꢀ4.71 ꢀ4.36 ꢀ5.50 ꢀ4.90 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.40 >ꢀ4.00 >ꢀ4.00
ꢀ4.88 ꢀ4.51 ꢀ4.14 ꢀ6.32 ꢀ4.99 >ꢀ4.30 ꢀ5.47 ꢀ4.67 >ꢀ4.00 ꢀ5.55 ꢀ5.13 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.43 >ꢀ4.00 >ꢀ4.00
ꢀ5.28 >ꢀ4.00 >ꢀ4.00 ꢀ5.81 ꢀ5.35 >ꢀ4.30 ꢀ5.49 ꢀ5.01 >ꢀ4.00 ꢀ5.66 ꢀ5.02 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.05 >ꢀ4.00 >ꢀ4.00
ꢀ4.66 ꢀ4.29 >ꢀ4.00 –
–
–
ꢀ4.64 ꢀ4.25 >ꢀ4.00 –
–
–
–
–
–
–
–
–
–
–
ꢀ4.84 ꢀ4.56 ꢀ4.28 ꢀ5.51 ꢀ4.95 ꢀ4.14
–
–
–
ꢀ4.80 ꢀ4.46 ꢀ4.12 ꢀ4.71
–
–
ꢀ4.61 ꢀ4.22 >ꢀ4.00 ꢀ5.09 ꢀ4.35 >ꢀ4.00
ꢀ4.88 ꢀ4.58 >ꢀ4.00 ꢀ5.37 ꢀ4.13 >ꢀ4.00
ꢀ4.89 ꢀ4.52 ꢀ4.15 ꢀ5.35 >ꢀ4.00 >ꢀ4.00
–
–
–
CNS cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
ꢀ5.01 ꢀ4.66 ꢀ4.31 ꢀ5.27 >ꢀ4.00 >ꢀ4.00
ꢀ4.75 ꢀ4.49 ꢀ4.23 ꢀ4.85 ꢀ4.45 ꢀ4.06
ꢀ4.83 ꢀ4.22 >ꢀ4.00 ꢀ5.53 ꢀ4.85 ꢀ4.31 ꢀ4.70 ꢀ4.26 >ꢀ4.00 ꢀ5.55 ꢀ5.12 ꢀ4.39 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.68 >ꢀ4.00 >ꢀ4.00
ꢀ4.88 ꢀ4.55 ꢀ4.23 ꢀ5.78 ꢀ5.25 ꢀ4.43 ꢀ4.81 ꢀ4.43 ꢀ4.05 ꢀ5.46 ꢀ4.87 ꢀ4.19 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.63 ꢀ4.28 >ꢀ4.00
ꢀ4.70 ꢀ4.34 >ꢀ4.00 ꢀ5.87 ꢀ5.10 ꢀ4.57 ꢀ5.34 ꢀ4.73 ꢀ4.08 ꢀ5.74 ꢀ5.45 ꢀ5.16 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.63 ꢀ4.21 >ꢀ4.00
–
–
–
–
ꢀ5.28 ꢀ4.67 ꢀ4.11
ꢀ4.38 >ꢀ4.00 >ꢀ4.00 ꢀ4.63 >ꢀ4.00 >ꢀ4.00
ꢀ4.59 >ꢀ4.00 >ꢀ4.00 ꢀ5.14
ꢀ4.79 ꢀ4.40 ꢀ4.01 ꢀ6.09 ꢀ4.84 >ꢀ4.30
ꢀ4.77 ꢀ4.41 ꢀ4.05 ꢀ5.76 ꢀ5.20 ꢀ4.52 ꢀ5.68 –
ꢀ4.68 >ꢀ4.30 ꢀ4.65 ꢀ4.29 >ꢀ4.00 ꢀ5.18
ꢀ4.70 ꢀ4.28 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.19 >ꢀ4.00 >ꢀ4.00
ꢀ5.67 ꢀ5.30 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 –
>ꢀ4.00 ꢀ5.80 ꢀ5.50 5.20 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.58 >ꢀ4.00 >ꢀ4.00
ꢀ4.52 ꢀ4.14
–
–
–
–
–
–
–
–
ꢀ4.87 ꢀ4.58 ꢀ4.29 ꢀ5.29 >ꢀ4.00 >ꢀ4.00
Melanoma
LOX IMVI
MALME-3M
M14
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
ꢀ4.87 ꢀ4.56 ꢀ4.26 ꢀ5.35 ꢀ4.09 >ꢀ4.00
ꢀ4.97 ꢀ4.65 ꢀ4.32 ꢀ5.31 ꢀ4.47 >ꢀ4.00
ꢀ4.74 ꢀ4.49 ꢀ4.24 ꢀ5.00 ꢀ4.31 >ꢀ4.00
ꢀ5.51 ꢀ4.85 >ꢀ4.00 ꢀ5.50 ꢀ4.98 ꢀ4.58 ꢀ5.67
ꢀ5.25 ꢀ4.73 ꢀ4.32 ꢀ5.47 ꢀ4.86 ꢀ4.30
ꢀ5.37 ꢀ5.11 ꢀ4.47 ꢀ5.02 ꢀ4.74 ꢀ4.46 ꢀ4.80 ꢀ4.46 ꢀ4.12 ꢀ4.63 ꢀ4.25 >ꢀ4.00 ꢀ4.34 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00
–
–
ꢀ5.82 ꢀ5.50 ꢀ5.18 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.46 >ꢀ4.00 >ꢀ4.00
–
–
–
–
–
–
ꢀ4.69 ꢀ4.41 ꢀ4.13 ꢀ4.29 >ꢀ4.00 >ꢀ4.00
ꢀ4.83 ꢀ4.54 ꢀ4.24 ꢀ5.11
ꢀ4.39 >ꢀ4.00
ꢀ5.06 ꢀ4.52 >ꢀ4.00 ꢀ4.79 >ꢀ4.30 >ꢀ4.30 ꢀ5.72 ꢀ5.37 ꢀ5.02 ꢀ5.28 >ꢀ4.00 >ꢀ4.00 ꢀ4.56 ꢀ4.11 >ꢀ4.00 ꢀ4.60 ꢀ4.06 >ꢀ4.00
ꢀ4.76 ꢀ4.49 ꢀ4.22 ꢀ5.75 ꢀ5.06 >ꢀ4.00
ꢀ4.75 ꢀ4.50 ꢀ4.25 ꢀ4.89 ꢀ4.38 >ꢀ4.00
ꢀ4.79 ꢀ4.52 ꢀ4.25 ꢀ4.59 >ꢀ4.00 >ꢀ4.00
ꢀ4.83 ꢀ4.53 ꢀ4.23 ꢀ5.27 ꢀ4.51 >ꢀ4.00
ꢀ4.87 ꢀ4.52 ꢀ4.17
ꢀ5.00 ꢀ4.56 ꢀ4.11
ꢀ5.07 ꢀ4.75 ꢀ4.44 ꢀ4.73 ꢀ4.38 ꢀ4.03 ꢀ5.72 ꢀ5.42 ꢀ5.13
ꢀ6.14 ꢀ5.11 ꢀ4.53 ꢀ5.46 ꢀ4.97 ꢀ4.46 ꢀ5.73 ꢀ5.44 ꢀ5.16
ꢀ4.57 ꢀ4.25 >ꢀ4.00 ꢀ4.71 ꢀ4.31 >ꢀ4.00
ꢀ4.16 >ꢀ4.00 >ꢀ4.00 ꢀ4.35 >ꢀ4.00 >ꢀ4.00
ꢀ4.89 ꢀ4.57 ꢀ4.26 ꢀ5.46 ꢀ4.97 ꢀ4.56 ꢀ5.34 ꢀ4.80 ꢀ4.36 ꢀ5.69 ꢀ5.37 ꢀ5.05 ꢀ4.71 ꢀ4.43 ꢀ4.16 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00
ꢀ4.89 ꢀ4.58 ꢀ4.27 ꢀ5.09 ꢀ4.81 ꢀ4.53 ꢀ4.85 ꢀ4.51 ꢀ4.17
ꢀ4.81 ꢀ4.53 ꢀ4.25 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.20 >ꢀ4.00 >ꢀ4.00
Ovarian cancer
IGROV1
ꢀ4.89 ꢀ4.57 ꢀ4.25 ꢀ5.06 ꢀ4.25 >ꢀ4.00
ꢀ4.94 ꢀ4.39 >ꢀ4.00 ꢀ5.04 >ꢀ4.30 >ꢀ4.30 ꢀ5.71 ꢀ5.23 ꢀ4.53 ꢀ5.51 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.60 >ꢀ4.00 >ꢀ4.00
ꢀ5.88 ꢀ5.48 ꢀ5.07 ꢀ5.94 ꢀ5.47 ꢀ4.74 ꢀ5.58 ꢀ5.16 ꢀ4.50 ꢀ5.62 ꢀ5.19 >ꢀ4.00 ꢀ4.31 >ꢀ4.00 >ꢀ4.00 ꢀ4.83 ꢀ4.14 >ꢀ4.00
ꢀ5.57 ꢀ5.13 ꢀ4.28 ꢀ4.93 >ꢀ4.00 >ꢀ4.00 ꢀ5.77 ꢀ5.09 ꢀ4.22 ꢀ4.10 >ꢀ4.00 ꢀ5.43 ꢀ4.61 >ꢀ4.00
ꢀ4.68 ꢀ4.38 ꢀ4.09 ꢀ4.67 >ꢀ4.30 >ꢀ4.30 ꢀ4.62 ꢀ4.39 ꢀ4.16 ꢀ5.58 ꢀ5.12 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.02 >ꢀ4.00 >ꢀ4.00
ꢀ5.17 ꢀ4.47 >ꢀ4.00 ꢀ5.16
ꢀ4.66 ꢀ4.33 >ꢀ4.00 ꢀ5.27 ꢀ4.86 ꢀ4.44 ꢀ4.73 ꢀ4.44 ꢀ4.16
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
SK-OV-3
ꢀ5.65 ꢀ5.11
ꢀ4.41 ꢀ5.73 ꢀ5.34 >ꢀ4.00
ꢀ5.09 ꢀ4.67 ꢀ4.32 ꢀ7.85 ꢀ6.01 ꢀ5.49
ꢀ4.68 ꢀ4.34 >ꢀ4.00 ꢀ5.23 ꢀ4.53 >ꢀ4.00
ꢀ4.83 ꢀ4.40 >ꢀ4.00 ꢀ5.55 ꢀ5.09 >ꢀ4.00
ꢀ4.24 >ꢀ4.00 ꢀ4.82 ꢀ4.27 >ꢀ4.00
–
–
–
–
ꢀ4.83 ꢀ4.50 ꢀ5.47 ꢀ4.87 >ꢀ4.00 ꢀ5.58 ꢀ5.22 ꢀ4.66 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.49 >ꢀ4.00 >ꢀ4.00
–
ꢀ4.89 ꢀ4.58 ꢀ4.27 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.59 ꢀ4.26 >ꢀ4.00
(continued on next page)

Table 2 (continued )
Cell lines
Respnse parameters: (A) log GI50b [M], (B) log TGIc [M], (C) log LC50d [M]
1b
2b
3b
4b
5b
6b
7b
1c
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
Renal cancer
786-0
A498
ꢀ4.82 ꢀ4.38 >ꢀ4.00 ꢀ4.90 ꢀ4.35 >ꢀ4.00
ꢀ4.81 ꢀ4.46 ꢀ4.12 ꢀ4.81 >ꢀ4.30 >ꢀ4.30 ꢀ4.88 ꢀ4.52 ꢀ4.15
ꢀ5.20 ꢀ4.83 ꢀ4.47 ꢀ4.76 ꢀ4.49 ꢀ4.22 ꢀ4.77 ꢀ4.51 ꢀ4.24 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.31 >ꢀ4.00 >ꢀ4.00
ꢀ4.86 ꢀ4.48 ꢀ4.09 ꢀ5.27 ꢀ4.95 ꢀ4.63 ꢀ5.77 ꢀ5.51 ꢀ5.25 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.44 >ꢀ4.00 >ꢀ4.00
ꢀ4.95 ꢀ4.61 ꢀ4.27 ꢀ5.72 ꢀ5.06 ꢀ4.50 ꢀ4.88 ꢀ4.28 >ꢀ4.00 ꢀ4.82 ꢀ4.43 ꢀ4.05 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.10 >ꢀ4.00 >ꢀ4.00
ꢀ4.72 >ꢀ4.00 >ꢀ4.00 ꢀ5.13 ꢀ4.70 >ꢀ4.30 ꢀ5.51 ꢀ4.77 >ꢀ4.00 ꢀ4.91 ꢀ4.57 ꢀ4.22 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.70 ꢀ4.13 >ꢀ4.00
ꢀ5.06 ꢀ4.78 ꢀ4.49 ꢀ5.22 ꢀ4.62 ꢀ4.06 ꢀ5.12 ꢀ4.63 ꢀ4.19 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.30 >ꢀ4.00 >ꢀ4.00
ꢀ4.63 ꢀ4.21 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.61 >ꢀ4.00 >ꢀ4.00
>ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.04 >ꢀ4.00 >ꢀ4.00 –
ꢀ4.83 ꢀ4.47 ꢀ4.12 ꢀ5.03 ꢀ4.32 >ꢀ4.00
ꢀ4.79 ꢀ4.44 ꢀ4.10 ꢀ4.80 >ꢀ4.00 >ꢀ4.00
ꢀ5.27 ꢀ4.74 ꢀ4.35 ꢀ5.22 ꢀ4.23 >ꢀ4.00
ꢀ4.77 ꢀ4.46 ꢀ4.16 ꢀ4.94 >ꢀ4.00 >ꢀ4.00 –
ꢀ4.55 ꢀ4.24 >ꢀ4.00 ꢀ4.61 ꢀ4.20 >ꢀ4.00
ꢀ4.94 ꢀ4.54 ꢀ4.14 ꢀ5.39 >ꢀ4.00 >ꢀ4.00
–
–
ACHN
–
–
–
CAKI-1
RXF393
SN12C
TK-10
–
–
ꢀ4.78 ꢀ4.49 ꢀ4.19
ꢀ5.20 ꢀ4.75 >ꢀ4.30 ꢀ4.89 ꢀ4.52 ꢀ4.14
ꢀ5.23 ꢀ4.70 ꢀ4.27 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.27 >ꢀ4.00 >ꢀ4.00
UO-31
ꢀ4.87 ꢀ4.34 >ꢀ4.00 ꢀ4.95 >ꢀ4.30 >ꢀ4.30 ꢀ5.38 >ꢀ4.00 >ꢀ4.00 ꢀ5.42 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.55 >ꢀ4.00 >ꢀ4.00
Prostate cancer
PC-3
DU-145
ꢀ4.99 ꢀ4.56 ꢀ4.14 ꢀ5.52 ꢀ4.84 >ꢀ4.00
ꢀ5.08 ꢀ4.56 ꢀ4.08 ꢀ5.66 >ꢀ4.30 >ꢀ4.30 ꢀ5.76 ꢀ5.29 ꢀ4.72 ꢀ5.46 ꢀ4.81 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.82 >ꢀ4.00 >ꢀ4.00
ꢀ4.66 ꢀ4.24 >ꢀ4.00 ꢀ4.53 >ꢀ4.00 >ꢀ4.00 ꢀ460
ꢀ4.06 >ꢀ4.00 ꢀ5.28 ꢀ4.70 >ꢀ4.30 ꢀ4.79 ꢀ4.48 ꢀ4.16
ꢀ5.82 ꢀ5.42 ꢀ5.01 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.16 >ꢀ4.00 >ꢀ4.00
Brest cancer
MCF-7
NCI/ADR-RES
ꢀ4.88 ꢀ4.58 ꢀ4.27 ꢀ5.08 >ꢀ4.00 >ꢀ4.00
ꢀ4.64 ꢀ4.08 >ꢀ4.00 ꢀ5.26 ꢀ4.48 >ꢀ4.00
ꢀ4.59 >ꢀ4.00 >ꢀ4.00 ꢀ5.81 >ꢀ4.30 >ꢀ4.30 ꢀ4.91 ꢀ4.27 >ꢀ4.00 ꢀ5.52 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.32 >ꢀ4.00 >ꢀ4.00
ꢀ4.75 ꢀ4.18 >ꢀ4.00 ꢀ4.99 ꢀ4.66 ꢀ4.33 ꢀ4.76 ꢀ4.34 >ꢀ4.00 ꢀ5.61 ꢀ5.24 ꢀ4.55 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.22 >ꢀ4.00 >ꢀ4.00
MDA-MB-231/ ꢀ5.54 ꢀ4.86 ꢀ4.19 ꢀ5.68 ꢀ5.22 >ꢀ4.00
ꢀ4.95 ꢀ4.53 ꢀ4.10
ꢀ5.14
ꢀ4.82 ꢀ4.50 ꢀ5.80 ꢀ5.35 >ꢀ4.00 ꢀ5.67 ꢀ5.29 ꢀ4.71 ꢀ4.58 >ꢀ4.00 >ꢀ4.00 ꢀ4.69 ꢀ4.19 >ꢀ4.00
ATCC
HS 578T
MDA-MB-435
MDA-N
BT-549
T-47D
ꢀ4.57 >ꢀ4.00 >ꢀ4.00 ꢀ5.07 >ꢀ4.00 >ꢀ4.00
ꢀ5.00 ꢀ4.66 ꢀ4.33 ꢀ5.67 ꢀ5.37
ꢀ4.85 ꢀ4.56 ꢀ4.27 ꢀ5.63 ꢀ5.28 >ꢀ4.00 –
ꢀ4.47 >ꢀ4.00 >ꢀ4.00 ꢀ5.52 ꢀ4.48 >ꢀ4.30 ꢀ5.23 ꢀ4.33 >ꢀ4.00 ꢀ5.31 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.61 >ꢀ4.00 >ꢀ4.00
–
ꢀ5.71 ꢀ5.39 ꢀ5.07 ꢀ6.64 ꢀ6.04 ꢀ5.54 ꢀ5.56 ꢀ5.12 ꢀ4.28 ꢀ5.70 ꢀ5.43 ꢀ5.16
ꢀ4.18 >ꢀ4.00 >ꢀ4.00 ꢀ4.39 >ꢀ4.00 >ꢀ4.00
ꢀ4.45 >ꢀ4.00 >ꢀ4.00
ꢀ5.77 ꢀ5.49 ꢀ5.20 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.49 >ꢀ4.00 >ꢀ4.00
ꢀ4.82 ꢀ4.01 >ꢀ4.00
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ꢀ5.19
ꢀ4.51 >ꢀ4.00 ꢀ5.01 >ꢀ4.00 >ꢀ4.00
ꢀ4.87 ꢀ4.49 ꢀ4.10
ꢀ5.42 ꢀ4.95 ꢀ4.56
ꢀ5.55 ꢀ4.96 ꢀ4.14 ꢀ5.78 ꢀ5.34 >ꢀ4.00
ꢀ4.87 ꢀ4.45 ꢀ4.14 ꢀ5.23 ꢀ4.48 ꢀ4.05
ꢀ5.35 >ꢀ4.00 >ꢀ4.00 –
ꢀ5.01 ꢀ4.44 ꢀ4.11
–
–
ꢀ4.71 ꢀ4.26 >ꢀ4.00 –
–
–
–
–
–
MG_MID
ꢀ5.42 ꢀ4.76 ꢀ4.41 ꢀ5.21 ꢀ4.65 ꢀ4.18
ꢀ5.34 ꢀ4.79 ꢀ4.34 ꢀ4.26 ꢀ4.07 ꢀ4.02 ꢀ4.51 ꢀ4.09 ꢀ4.00
– cell line not tested.
a
Data obtained from the NCI’s in vitro disease-oriented human tumor cells screen (see Refs. [38–43]).
The log of the molar concentration that inhibits 50% net cell growth.
The log of the molar concentration giving total growth inhibition.
b
c
d
The log of the molar concentration leading to 50% net cell death.

Table 3
Inhibition of in vitro cancer lines by selected 5,7-diamino-3-phenyl-2-anylino-quinoxalines, 2–7c, 1d, 3d, 4d, 5da
Cell lines
Response parameters: (A) log GI50b [M], (B) log TGIc [M], (C) log LC50d [M]
2c
5c
6c
7c
1d
3d
4d
5d
A
B
C
A
B
C
A
B
–
C
–
A
B
C
A
B
C
A
B
C
A
B
–
C
–
A
B
C
Leukemia
CCRF-CEM
HL-60(TB)
K-562
RPMI-8226
SR
ꢀ5.71 ꢀ5.06 ꢀ4.10 ꢀ5.53 >ꢀ4.00 >ꢀ4.00 –
ꢀ4.91 >ꢀ4.00 >ꢀ4.00 ꢀ5.64 ꢀ5.08 >ꢀ4.00 ꢀ5.60 >ꢀ4.00 >ꢀ4.00
–
ꢀ5.38 >ꢀ4.00 >ꢀ4.00
ꢀ5.51 ꢀ4.59 >ꢀ4.00 ꢀ5.29 >ꢀ4.00 >ꢀ4.00 ꢀ4.73 ꢀ4.19 >ꢀ4.00 ꢀ4.50 ꢀ4.02 >ꢀ4.00 ꢀ5.37 >ꢀ4.00 >ꢀ4.00 ꢀ5.10 >ꢀ4.00 >ꢀ4.00 ꢀ4.41 >ꢀ4.00 >ꢀ4.00 ꢀ6.53 >ꢀ4.00 >ꢀ4.00
ꢀ5.42 ꢀ4.49 >ꢀ4.00 ꢀ5.45 >ꢀ4.00 >ꢀ4.00 ꢀ4.96 >ꢀ4.00 >ꢀ4.00 – ꢀ5.01 >ꢀ4.00 >ꢀ4.00 ꢀ4.80 >ꢀ4.00 >ꢀ4.00 ꢀ4.40 ꢀ4.41 >ꢀ4.00 <ꢀ8.00 ꢀ4.61 >ꢀ4.00
–
–
ꢀ5.54 ꢀ5.07 ꢀ4.34 ꢀ5.46 >ꢀ4.00 >ꢀ4.00 ꢀ4.91 ꢀ4.33 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ5.40 ꢀ4.07 >ꢀ4.00 ꢀ5.42 ꢀ4.50 >ꢀ4.00 ꢀ4.55 ꢀ4.09 >ꢀ4.00 ꢀ6.47 >ꢀ4.00 >ꢀ4.00
ꢀ5.73 ꢀ4.54 >ꢀ4.00 ꢀ4.47 ꢀ4.62 >ꢀ4.00 ꢀ5.09 >ꢀ4.00 >ꢀ4.00 –
–
–
–
–
–
ꢀ5.33 ꢀ4.45 >ꢀ4.00 ꢀ4.45 >ꢀ4.00 >ꢀ4.00 ꢀ5.11
ꢀ4.09 >ꢀ4.00
MOLT-4
–
–
–
ꢀ5.20 >ꢀ4.00 >ꢀ4.00 ꢀ5.18 >ꢀ4.00 >ꢀ4.00 ꢀ4.41 >ꢀ4.00 >ꢀ4.00 ꢀ5.38 >ꢀ4.00 >ꢀ4.00 ꢀ5.39 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00
–
>ꢀ4.00 >ꢀ4.00
Non-small cell lung cancer
A549/ATCC
EKVX
HOP-62
ꢀ5.54 ꢀ4.88 ꢀ4.44 ꢀ4.74 ꢀ4.36 >ꢀ4.00 ꢀ4.62 ꢀ4.33 ꢀ4.05 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.37 >ꢀ4.00 >ꢀ4.00 ꢀ4.87 ꢀ4.28 >ꢀ4.00 ꢀ4.87 ꢀ4.51 ꢀ4.15
ꢀ5.42 ꢀ4.71 ꢀ4.31 ꢀ5.67 ꢀ5.08 ꢀ4.38 ꢀ4.83 ꢀ4.47 ꢀ4.11 ꢀ4.21 >ꢀ4.00 >ꢀ4.00 –
ꢀ5.67 ꢀ4.89 ꢀ4.45 ꢀ4.77 ꢀ4.42 ꢀ4.07 ꢀ4.67 ꢀ4.31 >ꢀ4.00 ꢀ4.44 ꢀ4.06 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.91 ꢀ4.11 >ꢀ4.00 ꢀ4.78 ꢀ4.46 ꢀ4.15
ꢀ5.87 ꢀ5.05 ꢀ4.20 ꢀ4.91 ꢀ4.53 ꢀ4.14 ꢀ4.52 >ꢀ4.00 >ꢀ4.00 – ꢀ4.64 ꢀ4.26 >ꢀ4.00 ꢀ5.42 ꢀ4.63 ꢀ4.09
ꢀ5.18 ꢀ4.37 >ꢀ4.00 ꢀ4.82 ꢀ4.31 >ꢀ4.00 ꢀ4.69 ꢀ4.31 >ꢀ4.00 ꢀ5.53 ꢀ4.60 >ꢀ4.00 – >ꢀ4.00 >ꢀ4.00 ꢀ5.52 ꢀ5.04 >ꢀ4.00 ꢀ4.72 ꢀ4.33 >ꢀ4.00 ꢀ4.75 ꢀ4.36 >ꢀ4.00
ꢀ5.77 ꢀ4.90 ꢀ4.45 ꢀ4.81 ꢀ4.40 >ꢀ4.00 ꢀ4.68 ꢀ4.40 ꢀ4.11 ꢀ4.81 ꢀ4.52 ꢀ4.22 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.90 ꢀ4.46 ꢀ4.02 ꢀ4.72 ꢀ4.40 ꢀ4.09 ꢀ4.93 ꢀ4.47 ꢀ4.02
ꢀ4.69 >ꢀ4.00 >ꢀ4.00
–
–
–
–
–
ꢀ4.69 ꢀ4.38 ꢀ4.08 ꢀ4.73 ꢀ4.22 >ꢀ4.00
ꢀ4.81 ꢀ4.07 >ꢀ4.00
HOP-92
–
–
–
–
–
–
–
–
NCI-H226
NCI-H23
NCI-H322M
NCI-H460
NCI-H522
ꢀ5.65 ꢀ4.82 ꢀ4.22 ꢀ4.67 ꢀ4.23 >ꢀ4.00 ꢀ4.77 ꢀ4.43 ꢀ4.09 ꢀ4.17 >ꢀ4.00 >ꢀ4.00 ꢀ4.45 >ꢀ4.00 >ꢀ4.00 ꢀ5.15 ꢀ4.45 >ꢀ4.00 ꢀ4.69 ꢀ4.42 ꢀ4.15
ꢀ4.46 >ꢀ4.00 >ꢀ4.00
ꢀ5.53 ꢀ4.90 ꢀ4.45 ꢀ4.74 ꢀ4.15 >ꢀ4.00 ꢀ4.40 >ꢀ4.00 >ꢀ4.00 ꢀ4.02 >ꢀ4.00 >ꢀ4.00 ꢀ4.70 >ꢀ4.00 >ꢀ4.00 ꢀ4.98 ꢀ4.47 >ꢀ4.00 ꢀ4.66 ꢀ4.18 >ꢀ4.00 ꢀ4.56 >ꢀ4.00 >ꢀ4.00
ꢀ6.05 ꢀ5.37 ꢀ4.67 ꢀ5.08 ꢀ4.47 >ꢀ4.00 ꢀ4.19 >ꢀ4.00 >ꢀ4.00 ꢀ4.56 >ꢀ4.00 >ꢀ4.00 ꢀ5.49 >ꢀ4.00 >ꢀ4.00 ꢀ5.12 ꢀ4.47 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.67 >ꢀ4.00 >ꢀ4.00
Colon cancer
COLO 205
HCC-2998
HCT-116
HCT-15
HT29
KM12
SW-620
ꢀ4.97 ꢀ4.65 ꢀ4.33 ꢀ4.69 ꢀ4.17 >ꢀ4.00 ꢀ4.70 ꢀ4.44 ꢀ4.18
ꢀ5.60 ꢀ4.86 ꢀ4.39
ꢀ4.52 >ꢀ4.00 >ꢀ4.00 ꢀ4.71 >ꢀ4.00 >ꢀ4.00 ꢀ4.97 ꢀ4.47 >ꢀ4.00 ꢀ4.66 ꢀ4.32 >ꢀ4.00 ꢀ4.55 >ꢀ4.00 >ꢀ4.00
ꢀ5.33 ꢀ4.77 ꢀ4.15
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ꢀ5.63 ꢀ5.00 ꢀ4.50 ꢀ4.80 ꢀ4.32 >ꢀ4.00 ꢀ4.83 ꢀ4.09 >ꢀ4.00 ꢀ4.82 ꢀ4.54 ꢀ4.27 ꢀ4.83 >ꢀ4.00 >ꢀ4.00 ꢀ5.03 ꢀ4.32 >ꢀ4.00 ꢀ4.83 ꢀ4.55 ꢀ4.26 ꢀ4.67 >ꢀ4.00 >ꢀ4.00
ꢀ5.69 ꢀ4.91 ꢀ4.37 ꢀ4.70 >ꢀ4.00 >ꢀ4.00 ꢀ4.44 >ꢀ4.00 >ꢀ4.00 ꢀ4.46 >ꢀ4.00 >ꢀ4.00 –
–
–
–
–
–
–
–
–
–
–
ꢀ4.87 ꢀ4.56 ꢀ4.25 ꢀ4.87 ꢀ4.37 >ꢀ4.00
ꢀ4.75 ꢀ4.34 >ꢀ4.00 ꢀ5.02 >ꢀ4.00 >ꢀ4.00
ꢀ5.36 ꢀ4.75 ꢀ4.37
–
–
–
ꢀ4.64 ꢀ4.29 >ꢀ4.00 –
–
–
–
ꢀ5.99 ꢀ5.22 ꢀ4.58 ꢀ5.20 ꢀ4.40 >ꢀ4.00 ꢀ4.84 ꢀ4.39 >ꢀ4.00 ꢀ4.56 >ꢀ4.00 >ꢀ4.00 ꢀ4.55 >ꢀ4.00 >ꢀ4.00 ꢀ4.95 >ꢀ4.00 >ꢀ4.00 ꢀ4.68 ꢀ4.31 >ꢀ4.00 ꢀ4.62 >ꢀ4.00 >ꢀ4.00
ꢀ5.65 ꢀ4.99 ꢀ4.50 ꢀ5.01 ꢀ4.52 ꢀ4.04 ꢀ4.71 ꢀ4.30 >ꢀ4.00 ꢀ4.53 >ꢀ4.00 >ꢀ4.00 ꢀ4.58 >ꢀ4.00 >ꢀ4.00 ꢀ4.68 ꢀ4.08 >ꢀ4.00 ꢀ4.64 ꢀ4.30 >ꢀ4.00 ꢀ4.93 >ꢀ4.00 >ꢀ4.00
CNS cancer
SF-268
SF-295
SF-539
SNB-19
SNB-75
U251
ꢀ5.76 ꢀ5.15
ꢀ5.66 ꢀ5.07 ꢀ4.40 ꢀ4.86 ꢀ4.51 ꢀ4.16 ꢀ4.69 ꢀ4.41 ꢀ4.14
ꢀ4.87 ꢀ4.53 ꢀ4.19 ꢀ4.74 ꢀ4.45 ꢀ4.15
ꢀ5.60 ꢀ4.90 ꢀ4.45 ꢀ4.68 ꢀ4.28 >ꢀ4.00 ꢀ4.76 ꢀ4.47 ꢀ4.18
ꢀ6.90 ꢀ5.57 ꢀ4.92 ꢀ4.63 ꢀ4.31 >ꢀ4.00 –
ꢀ5.58 ꢀ4.97 ꢀ4.48 ꢀ4.92 ꢀ4.50 ꢀ4.08 ꢀ4.63 ꢀ4.10 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.99 >ꢀ4.00 >ꢀ4.00 ꢀ4.79 ꢀ4.50 ꢀ4.21 ꢀ4.84 >ꢀ4.00 >ꢀ4.00
ꢀ4.57 ꢀ4.77 ꢀ4.28 >ꢀ4.00 ꢀ4.86 ꢀ4.32 >ꢀ4.00 ꢀ4.39 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.86 ꢀ4.29 >ꢀ4.00 ꢀ4.75 ꢀ4.41 ꢀ4.07 ꢀ4.79 ꢀ4.35 >ꢀ4.00
ꢀ4.39 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.75 ꢀ4.22 >ꢀ4.00 ꢀ4.86 ꢀ4.52 ꢀ4.19
ꢀ4.47 >ꢀ4.00 >ꢀ4.00 ꢀ5.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.84 ꢀ4.38 >ꢀ4.00 ꢀ4.67 ꢀ4.40 ꢀ4.12
ꢀ4.60 >ꢀ4.00 >ꢀ4.00
–
–
–
–
–
–
ꢀ4.50 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.77 ꢀ4.24 >ꢀ4.00 ꢀ4.70 ꢀ4.38 ꢀ4.06 ꢀ4.25 >ꢀ4.00 >ꢀ4.00
–
–
–
–
–
–
–
–
–
–
–
ꢀ4.68 ꢀ4.32 >ꢀ4.00 ꢀ4.49 ꢀ4.20 >ꢀ4.00
Melanoma
LOX IMVI
MALME-3M
M14
SK-MEL-2
SK-MEL-28
SK-MEL-5
UACC-257
UACC-62
ꢀ5.53 ꢀ4.89 ꢀ4.44 ꢀ4.79 ꢀ4.47 ꢀ4.14 ꢀ4.36 >ꢀ4.00 >ꢀ4.00 ꢀ4.92 ꢀ4.58 ꢀ4.24 ꢀ4.29 >ꢀ4.00 >ꢀ4.00 ꢀ5.13 ꢀ4.61 ꢀ4.14
ꢀ6.37 ꢀ5.29 ꢀ4.52 ꢀ4.80 ꢀ4.43 ꢀ4.05 ꢀ4.73 ꢀ4.45 ꢀ4.18 ꢀ4.48 ꢀ4.02 >ꢀ4.00 ꢀ4.71 ꢀ4.30 >ꢀ4.00
ꢀ4.64 ꢀ4.39 ꢀ4.13
ꢀ5.52 ꢀ5.07 >ꢀ4.00
ꢀ4.71 ꢀ4.43 ꢀ4.15
–
–
–
–
–
–
ꢀ5.80 ꢀ5.11
ꢀ4.54 ꢀ4.85 ꢀ4.15 >ꢀ4.00 ꢀ4.77 ꢀ4.35 >ꢀ4.00 ꢀ4.40 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.49 >ꢀ4.00 >ꢀ4.00 ꢀ4.80 ꢀ4.51 ꢀ4.23 ꢀ4.48 >ꢀ4.00 >ꢀ4.00
ꢀ5.64 ꢀ4.99 ꢀ4.42 ꢀ5.25 ꢀ4.63 ꢀ4.05 ꢀ4.37 >ꢀ4.00 >ꢀ4.00 ꢀ4.39 >ꢀ4.00 >ꢀ4.00 –
>ꢀ4.00 >ꢀ4.00 ꢀ5.21 ꢀ4.51 >ꢀ4.00 ꢀ4.42 >ꢀ4.00 >ꢀ4.00 ꢀ4.72 ꢀ4.20 >ꢀ4.00
ꢀ4.61 >ꢀ4.00 >ꢀ4.00 ꢀ4.86 ꢀ4.24 >ꢀ4.00 ꢀ4.63 ꢀ4.27 >ꢀ4.00 ꢀ5.17 ꢀ4.47 >ꢀ4.00
ꢀ4.61 ꢀ5.01 ꢀ4.54 ꢀ4.08 ꢀ4.91 ꢀ4.50 ꢀ4.08 ꢀ4.74 ꢀ4.27 >ꢀ4.00 ꢀ4.62 >ꢀ4.00 >ꢀ4.00 ꢀ4.67 ꢀ4.02 >ꢀ4.00 ꢀ4.81 ꢀ4.48 ꢀ4.15 ꢀ4.90 ꢀ4.49 ꢀ4.07
ꢀ5.50 ꢀ4.81 ꢀ4.41 ꢀ4.67 ꢀ4.19 >ꢀ4.00 ꢀ4.71 ꢀ4.33 >ꢀ4.00 ꢀ4.84 ꢀ4.52 ꢀ4.19
ꢀ5.72 ꢀ5.19
ꢀ5.66 ꢀ4.91 ꢀ4.43 ꢀ4.55 ꢀ4.06 >ꢀ4.00 ꢀ4.63 ꢀ4.37 ꢀ4.11
ꢀ5.39 ꢀ4.74 ꢀ4.32 ꢀ4.79 ꢀ4.32 >ꢀ4.00 ꢀ4.80 ꢀ4.48 ꢀ4.16
ꢀ4.57 ꢀ4.26 >ꢀ4.00 ꢀ4.36 >ꢀ4.00 >ꢀ4.00 ꢀ4.75 ꢀ4.23 >ꢀ4.00 ꢀ4.78 ꢀ4.50 ꢀ4.22 ꢀ4.76 ꢀ4.39 ꢀ4.02
ꢀ4.79 ꢀ4.51 ꢀ4.23 ꢀ4.42 >ꢀ4.00 >ꢀ4.00 ꢀ5.17
ꢀ4.37 >ꢀ4.00 ꢀ4.78 ꢀ4.50 ꢀ4.22 ꢀ4.75 ꢀ4.41 ꢀ4.06
Ovarian cancer
IGROV1
ꢀ5.58 ꢀ4.91 ꢀ4.42 ꢀ4.94 ꢀ4.49 ꢀ4.04 ꢀ4.55 >ꢀ4.00 >ꢀ4.00 ꢀ4.74 ꢀ4.10 >ꢀ4.00 –
ꢀ5.65 ꢀ5.06 ꢀ4.26 ꢀ4.97 ꢀ4.57 ꢀ4.18 ꢀ4.81 ꢀ4.38 >ꢀ4.00 ꢀ4.79 ꢀ4.39 >ꢀ4.00 –
ꢀ5.54 ꢀ4.79 ꢀ4.23 ꢀ4.48 >ꢀ4.00 >ꢀ4.00 ꢀ5.08 ꢀ4.45 >ꢀ4.00 ꢀ4.45 >ꢀ4.00 >ꢀ4.00 –
>ꢀ4.00 >ꢀ4.00 ꢀ5.53 ꢀ4.56 >ꢀ4.00 ꢀ4.60 >ꢀ4.00 >ꢀ4.00 ꢀ5.32 >ꢀ4.00 >ꢀ4.00
OVCAR-3
OVCAR-4
OVCAR-5
OVCAR-8
SK-OV-3
>ꢀ4.00 >ꢀ4.00 ꢀ4.93 ꢀ4.33 >ꢀ4.00 ꢀ4.79 ꢀ4.47 ꢀ4.16
ꢀ4.91 ꢀ4.42 >ꢀ4.00
>ꢀ4.00 >ꢀ4.00 ꢀ4.70 >ꢀ4.00 >ꢀ4.00 ꢀ4.64 ꢀ4.25 >ꢀ4.00 ꢀ4.78 ꢀ4.27 >ꢀ4.00
ꢀ5.49 ꢀ4.79 ꢀ4.39 ꢀ4.60 ꢀ4.23 >ꢀ4.00 ꢀ4.69 ꢀ4.32 >ꢀ4.00 ꢀ4.10 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.41 ꢀ4.23 ꢀ4.04 ꢀ4.72 ꢀ4.34 >ꢀ4.00 ꢀ4.22 >ꢀ4.00 >ꢀ4.00
ꢀ5.54 ꢀ4.79 ꢀ4.30 ꢀ4.55 ꢀ4.05 >ꢀ4.00 ꢀ4.65 ꢀ4.32 ꢀ4.00 ꢀ4.42 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.61 >ꢀ4.00 >ꢀ4.00 ꢀ4.78 ꢀ4.46 ꢀ4.14
ꢀ4.92 ꢀ4.40 >ꢀ4.00
ꢀ5.46 ꢀ4.79 ꢀ4.16 ꢀ4.62 ꢀ4.18 >ꢀ4.00 ꢀ4.68 ꢀ4.38 ꢀ4.08 ꢀ4.55 ꢀ4.01 >ꢀ4.00 ꢀ4.48 >ꢀ4.00 >ꢀ4.00 ꢀ4.83 ꢀ4.40 >ꢀ4.00 ꢀ4.80 ꢀ4.50 ꢀ4.20 ꢀ4.75 ꢀ4.35 >ꢀ4.00
(continued on next page)

Table 3 (continued )
Cell lines
Response parameters: (A) log GI50b [M], (B) log TGIc [M], (C) log LC50d [M]
2c
5c
6c
7c
1d
3d
4d
5d
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
Renal cancer
786-0
A498
ꢀ5.66 ꢀ4.94 ꢀ4.47 ꢀ4.71 ꢀ4.39 ꢀ4.06 ꢀ4.80 ꢀ4.44 ꢀ4.08 ꢀ4.05 >ꢀ4.00 >ꢀ4.00 ꢀ4.28 >ꢀ4.00 >ꢀ4.00 ꢀ4.66 ꢀ4.04 >ꢀ4.00
ꢀ5.71 ꢀ4.84 >ꢀ4.00 ꢀ6.35 ꢀ4.91 ꢀ4.36 ꢀ4.66 ꢀ4.40 ꢀ4.15
ꢀ5.37 ꢀ4.75 ꢀ4.29 ꢀ4.66 ꢀ4.07 >ꢀ4.00 ꢀ4.55 >ꢀ4.00 >ꢀ4.00
ꢀ5.38 ꢀ4.62 >ꢀ4.00 ꢀ4.84 ꢀ4.44 ꢀ4.05 ꢀ4.71 ꢀ4.43 ꢀ4.15 ꢀ4.31 >ꢀ4.00 >ꢀ4.00 ꢀ5.01 >ꢀ4.00 >ꢀ4.00 ꢀ4.85 ꢀ4.39 >ꢀ4.00 ꢀ4.74 ꢀ4.44 ꢀ4.13
ꢀ5.99 ꢀ5.36 ꢀ4.69 ꢀ4.60 ꢀ4.07 >ꢀ4.00 ꢀ4.68 ꢀ4.33 >ꢀ4.00 ꢀ4.36 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.85 ꢀ4.25 >ꢀ4.00 ꢀ4.88 ꢀ4.53 ꢀ4.19
ꢀ5.36 ꢀ4.65 ꢀ4.06 ꢀ4.84 ꢀ4.50 ꢀ4.17 ꢀ4.71 ꢀ4.28 >ꢀ4.00 – >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.63 >ꢀ4.00 >ꢀ4.00 ꢀ4.75 ꢀ4.45 ꢀ4.15
ꢀ5.76 ꢀ5.07 ꢀ4.53 ꢀ4.75 ꢀ4.42 ꢀ4.09 ꢀ4.69 ꢀ4.33 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.51 >ꢀ4.00 >ꢀ4.00 ꢀ4.84 ꢀ4.50 ꢀ4.16
–
ꢀ4.64 ꢀ4.31 ꢀ4.21 >ꢀ4.00 >ꢀ4.00
–
–
–
>ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.66 ꢀ4.03 >ꢀ4.00 ꢀ4.56 ꢀ4.34 ꢀ4.11
–
–
–
ACHN
–
–
–
–
–
–
–
–
–
ꢀ4.85 ꢀ4.56 ꢀ4.27 ꢀ4.84 ꢀ4.08 >ꢀ4.00
CAKI-1
RXF393
SN12C
TK-10
ꢀ4.72 ꢀ5.52 ꢀ4.71
ꢀ5.52 ꢀ4.71 ꢀ4.02
ꢀ4.75 ꢀ4.35 >ꢀ4.00
–
–
ꢀ4.76 ꢀ4.37 >ꢀ4.00 ꢀ4.51 >ꢀ4.00 >ꢀ4.00
UO-31
ꢀ5.46 ꢀ4.82 ꢀ4.34 ꢀ4.88 ꢀ4.22 >ꢀ4.00 ꢀ4.53 >ꢀ4.00 >ꢀ4.00 ꢀ4.31 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.85 ꢀ4.12 >ꢀ4.00 ꢀ4.49 >ꢀ4.00 >ꢀ4.00 ꢀ4.64 >ꢀ4.00 >ꢀ4.00
Prostate cancer
PC-3
DU-145
ꢀ5.41 ꢀ4.76 ꢀ4.19 ꢀ4.81 >ꢀ4.00 >ꢀ4.00 ꢀ5.14
ꢀ4.33 >ꢀ4.00 ꢀ4.13 >ꢀ4.00 >ꢀ4.00 ꢀ5.19 >ꢀ4.00 >ꢀ4.00 ꢀ5.24 ꢀ4.44 >ꢀ4.00 ꢀ4.53 >ꢀ4.00 >ꢀ4.00 ꢀ4.77 >ꢀ4.00 >ꢀ4.00
ꢀ4.21 >ꢀ4.00 >ꢀ4.00 ꢀ4.84 >ꢀ4.00 >ꢀ4.00 ꢀ4.95 ꢀ4.60 ꢀ4.25 ꢀ4.70 ꢀ4.42 ꢀ4.15 ꢀ4.42 >ꢀ4.00 >ꢀ4.00
ꢀ5.34 ꢀ4.60 ꢀ4.01 ꢀ5.00 ꢀ4.57 ꢀ4.13 ꢀ4.76 ꢀ4.43 ꢀ4.10
Brest cancer
MCF-7
NCI/ADR-RES
ꢀ5.77 ꢀ5.34 ꢀ4.84 ꢀ4.85 ꢀ4.15 >ꢀ4.00 ꢀ4.69 >ꢀ4.00 >ꢀ4.00 ꢀ4.27 >ꢀ4.00 >ꢀ4.00 ꢀ4.78 >ꢀ4.00 >ꢀ4.00 ꢀ5.28 ꢀ4.42 >ꢀ4.00 ꢀ4.70 ꢀ4.20 >ꢀ4.00 ꢀ5.24 >ꢀ4.00 >ꢀ4.00
ꢀ5.95 ꢀ5.41 ꢀ4.74 ꢀ4.93 ꢀ4.44 >ꢀ4.00 ꢀ4.74 ꢀ4.44 ꢀ4.15 ꢀ4.56 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.72 ꢀ4.22 >ꢀ4.00 ꢀ4.78 ꢀ4.46 ꢀ4.14 ꢀ4.67 >ꢀ4.00 >ꢀ4.00
ꢀ4.45 >ꢀ4.00
ꢀ5.88 ꢀ5.38 ꢀ4.59 ꢀ4.97 ꢀ4.47 >ꢀ4.00 ꢀ4.70 ꢀ4.27 >ꢀ4.00 ꢀ4.36 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.52 >ꢀ4.00 >ꢀ4.00 ꢀ4.57 ꢀ4.21 >ꢀ4.00 ꢀ4.86 ꢀ4.12 >ꢀ4.00
MDA-MB-231/ATCC ꢀ5.40 ꢀ4.66 ꢀ4.06 ꢀ4.99 ꢀ4.58 ꢀ4.18 ꢀ5.41 ꢀ4.54 >ꢀ4.00 ꢀ4.95 ꢀ4.49 ꢀ4.03 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.78 ꢀ4.27 >ꢀ4.00 ꢀ4.76 ꢀ4.42 ꢀ4.08 ꢀ5.10
HS 578T
MDA-MB-435
MDA-N
BT-549
T-47D
ꢀ6.41 ꢀ5.74 ꢀ5.30 ꢀ5.30 ꢀ4.68 ꢀ4.03 ꢀ4.80 ꢀ4.49 ꢀ4.17
ꢀ4.52 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.74 ꢀ4.22 >ꢀ4.00 ꢀ4.79 ꢀ4.48 ꢀ4.18
ꢀ4.95 ꢀ4.47 >ꢀ4.00
ꢀ6.12 ꢀ5.65 ꢀ5.27
ꢀ5.83 ꢀ5.16 ꢀ4.42
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ꢀ4.82 ꢀ4.46 ꢀ4.09 ꢀ4.47 >ꢀ4.00 >ꢀ4.00
ꢀ4.66 ꢀ4.36 ꢀ4.05 ꢀ5.20 ꢀ4.28 >ꢀ4.00
ꢀ5.63 ꢀ5.04 ꢀ4.29 ꢀ4.61 ꢀ4.10 >ꢀ4.00
–
–
–
–
–
–
>ꢀ4.00 >ꢀ4.00 >ꢀ4.00 ꢀ4.88 >ꢀ4.00 >ꢀ4.00
–
–
–
ꢀ4.54 >ꢀ4.00 >ꢀ4.00
MG_MID
ꢀ5.66 ꢀ4.96 ꢀ4.40 ꢀ4.93 ꢀ4.34 ꢀ4.05 ꢀ4.74 ꢀ4.29 ꢀ4.04 ꢀ4.48 ꢀ4.11
ꢀ4.03 ꢀ4.48 ꢀ4.02 ꢀ4.00 ꢀ4.93 ꢀ4.27 ꢀ4.01 ꢀ4.67 ꢀ4.33 ꢀ4.09 ꢀ4.88 ꢀ4.21 ꢀ4.01
– cell line not tested.
a
Data obtained from the NCI’s in vitro disease-oriented human tumor cells screen (see Refs. [38–43]).
The log of the molar concentration that inhibits 50% net cell growth.
The log of the molar concentration giving total growth inhibition.
b
c
d
The log of the molar concentration leading to 50% net cell death.

P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
1587
Table 4
C31H30N6O9: C, 59.04; H, 4.80; N, 13.33; found C, 59.10; H, 4.72; N,
13.20.
The in vitro selectivity towards leukemia cell lines for compounds 7b and 5d
Compound Leukemia log
cell lines GI50
[M]
Selectivity towards
leukemia cell lines (
for log GI50
Mean value for all tested
cell lines (MG_MID)c for
log GI50 [M]
a
D)
4.1.2.2. General procedure for preparation of 5,7-dinitro-3-phenyl-2-
phenoxy substituted quinoxalines (34–40) and 5,7-dinitro-3-phenyl-
2-thiophenol substituted quinoxalines (41–44). A mixture of
equimolar amounts (150 mg, 0.45 mmol) of 8 and the corre-
sponding phenols (16–22) or thiophenols (23–26) (0.45 mmol) in
anhydrous DMF (5 mL) in the presence of one mole equivalent of
Cs2CO3 was stirred at 70 ꢁC or at room temperature (35, 40) for the
time reported below. Then, water was added to give solids which
were filtered off or solutions which were extracted several times
with CHCl3. The crude products were purified by flash chroma-
tography using a mixture of petroleum ether/ethyl acetate as eluent
in different ratios or by recrystallization as reported below.
b
7b
SR
HL-60(TB) ꢀ5.64 1.38
MOLT-4
ꢀ5.74 1.48
ꢀ6.30 2.04
ꢀ4.26
5d
HL-60(TB) ꢀ6.53 1.65
ꢀ4.88
K-562
RPMI-
8226
<ꢀ8.00 3.12
ꢀ6.47 1.59
a
The log of the molar concentration that inhibits 50% net cell growth, data
obtained from the NCI’s in vitro disease-oriented human tumor cells screen (see
Refs. [19–21]).
b
The reported data represent the logarithmic difference between the parameter
values referred to the leukemia cell line and the same mean graph midpoint,
D is
4.1.2.2.1. 5,7-Dinitro-3-phenyl-2-[(4-methoxy)phenoxy]quinoxali
ne (34). This compound was obtained in 97% yield by the protocol
described in the general procedure starting from 8 (150 mg,
0.45 mmol), 4-methoxyphenol (16) (56 mg, 0.45 mmol) and Cs2CO3
(147 mg, 0.45 mmol) at 70 ꢁC for 2 h; m.p. 201–202 ꢁC (from
CH3CN); TLC (petroleum ether/ethyl acetate 8:2): Rf 0.5; IR (nujol):
considered low <1, moderate >1 and >3, high if >3.
c
MG_MID ¼ mean graph midpoint ¼ arithmetical mean value for all tested cancer
cell lines.
4.1.2.1.7. N-[4-[(5,7-Dinitro-3-phenylquinoxalin-2-ylamino)methy
l]benzoyl]glutamic acid diethyl ester (33) [44]. This compound was
obtained in 29% yield by the protocol described in the general
procedure starting from 8 (150 mg, 0.45 mmol) and N-[4(amino-
methyl)benzoyl]glutamic acid diethyl ester (15) [34] (454 mg,
1.35 mmol) for 168 h; m.p. 301–303 ꢁC (from C3H8O); TLC (petro-
n
1600, 1535, 1345 cmꢀ1; UV (EtOH): lmax 345, 206 nm; 1H NMR
(CDCl3):
d
8.78 (1H, d, J ¼ 2 Hz, H-6), 8.71 (1H, d, J ¼ 2 Hz, H-8),
8.50–8.38 (2H, m, Ar), 7.68–7.50 (3H, m, Ar), 7.20 (2H, d, J ¼ 9 Hz,
Ar), 7.02 (2H, d, J ¼ 9 Hz, Ar), 3.66 (3H, s, CH3). GC/MS: m/z 418 [M]þ.
Anal. Calcd. for C21H14N4O6: C, 60.29; H, 3.37; N, 13.39; found C,
60.18; H, 3.29; N, 13.20.
leum ether/ethyl acetate 4:6): Rf 0.30; IR (nujol):
n
3370, 3320, 1720,
8.73 (1H, d,
1645, 1620, 1525, 1410, 1350 cmꢀ1 1H NMR (CDCl3):
;
d
4.1.2.2.2. 5,7-Dinitro-3-phenyl-2-[(3,5-dimethoxy)phenoxy]quino
xaline (35). This compound was obtained in 88% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol), 3,5-dimethoxyphenol (17) (69 mg,
0.45 mmol) and Cs2CO3 (147 mg, 0.45 mmol) under a N2 atmo-
sphere at room temperature for 6 h and 30 min; the compound was
purified by silica gel column chromatography eluting with a 8:2
mixture of petroleum ether/ethyl acetate; m.p. 169–171 ꢁC (from
CH3CN); TLC (petroleum ether/ethyl acetate 8:2): Rf 0.43; IR (nujol):
J ¼ 2.4 Hz, H-6), 8.48 (1H, d, J ¼ 2.2 Hz, H-8), 7.90–7.79 (4H, m, Ar),
7.60 (3H, d, J ¼ 7.8 Hz, Ar), 7.45 (2H, d, J ¼ 8.2 Hz, Ar), 7.09 (1H, d,
J ¼ 7.4 Hz, exc. with D2O, CONH), 6.17 (1H, t, exc. with D2O, NHCH2),
4.86 (2H, d, J ¼ 5.6 Hz, NHCH2), 4.86–4.70 (1H, m, CH), 4.23 (2H, q,
J ¼ 7.2 Hz, CH2), 4.11 (2H, q, J ¼ 7.2 Hz, CH2), 2.60–2.02 (4H, m,
CH2CH2), 1.30 (3H, t, J ¼ 7.2 Hz, CH3), 1.23 (3H, t, J ¼ 7.2 Hz, CH3). 13
C
NMR (CDCl3):
d
14 (2 ꢃ CH3), 26.3 (CH2), 30.3 (CH2), 43.3 (CH2), 52.8
(CH), 61.2 (2 ꢃ CH2), 116 (CH), 126.3 (CH), 126.9 (2 ꢃ CH), 127.3
(2 ꢃ CH), 127.6 (2 ꢃ CH), 128.6 (CH), 129.1 (2 ꢃ CH), 130 (C), 132.3
(C), 135.4 (C), 138.3 (C), 141.5 (C), 143 (C), 143.4 (C), 147 (C), 154.3 (C),
167.3 (C), 171.3 (C), 173 (C). GC/MS: m/z 630 [M]þ. Anal. Calcd. for
n
1625, 1535, 1345 cmꢀ1; UV (EtOH): lmax 364, 203 nm; 1H NMR
(CDCl3):
d
8.84 (1H, d, J ¼ 2.8 Hz, H-6), 8.74 (1H, d, J ¼ 2.8 Hz, H-8),
8.48–8.36 (2H, m, Ar), 7.65–7.53 (3H, m, Ar), 6.50–6.40 (3H, m, Ar),
3.83 (6H, s, 2 ꢃ CH3). GC/MS: m/z 448 [M]þ. Anal. Calcd. for
C22H16N4O7: C, 58.93; H, 3.60; N, 12.50; found C, 58.75; H, 3.49; N,
12.33.
Table 5
Antitumor activity (log GI50 (MG_MID)) comparison between compounds 1–7b, 5
4.1.2.2.3. 5,7-Dinitro-3-phenyl-2-[(3,4-dimethoxy)phenoxy]quino
xaline (36) [44]. This compound was obtained in 61% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol), 3,4-dimethoxyphenol (18) (69 mg,
0.45 mmol) and Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 4 h and
40 min; m.p. 192–194 ꢁC (from CH3CN); TLC (petroleum ether/ethyl
and 1–5d and the corresponding 2-anylino derivatives 1–7a previously reported
[33]
MG_MID log GI50
Series 2-benzylamino
MG_MID log GI50
Series 2-anylino
1a [33]
2a [33]
3a [33]
4a [33]
5a [33]
6a [33]
7a [33]
1b
2b
3b
4b
5b
6b
7b
ꢀ4.87
ꢀ5.23
ꢀ5.01
ꢀ5.42
ꢀ5.21
ꢀ5.34
ꢀ4.26
ꢀ4.73
ꢀ5.04
ꢀ4.72
ꢀ4.90
ꢀ5.08
ꢀ4.82
ꢀ4.87
acetate 7:3): Rf 0.41; IR (nujol):
(CDCl3):
n ;
1600, 1510, 1340 cmꢀ1 1H NMR
d
8.80 (1H, d, J ¼ 2.4 Hz, H-6), 8.73 (1H, d, J ¼ 2.4 Hz, H-8),
7.45–7.40 (2H, m, Ar), 7.64–7.56 (3H, m, Ar), 6.99 (1H, d, J ¼ 8.8 Hz,
Ar), 6.86 (1H, d, J ¼ 2.6 Hz, Ar), 6.83–6.77 (1H, m, Ar), 3.96 (3H, s,
CH3), 3.90 (3H, s, CH3). 13C NMR (CDCl3):
d
56 (2 ꢃ CH3), 108.3 (CH),
Series 2-phenoxy
115.8 (CH), 116.2 (CH), 118 (CH), 127.3 (2 ꢃ CH), 128.2 (CH), 128.6
(CH), 129.1 (2 ꢃ CH), 131.6 (C), 132 (C), 139.5 (C), 142.5 (C), 144 (C),
145.8 (C), 148.4 (C), 150 (C), 150.6 (C), 175 (C). GC/MS: m/z 448 [M]þ.
Anal. Calcd. for C22H16N4O7: C, 58.93; H, 3.60; N, 12.50; found C,
58.76; H, 3.58; N, 12.30.
1c
2c
3c
4c
5c
6c
7c
ꢀ4.51
1a [33]
2a [33]
3a [33]
4a [33]
5a [33]
6a [33]
7a [33]
ꢀ4.73
ꢀ5.04
ꢀ4.72
ꢀ4.90
ꢀ5.08
ꢀ4.82
ꢀ4.87
ꢀ5.66
–
No tested
ꢀ4.93
ꢀ4.74
ꢀ4.48
4.1.2.2.4. 5,7-Dinitro-3-phenyl-2-[(3,4,5-trimethoxy)phenoxy]qui
noxaline (37). This compound was obtained in 93% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol), 3,4,5-trimethoxyphenol (19) (83 mg,
0.45 mmol) and Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 1 h and
40 min; the compound was purified by silica gel column chroma-
tography eluting with a 9:1 mixture of petroleum ether/ethyl
acetate; m.p. 230–231 ꢁC (from CH3CN); TLC (petroleum ether/ethyl
Series 2-thiophenyl
1d
2d
3d
4d
5d
ꢀ4.48
1a [33]
3a [33]
5a [33]
6a [33]
7a [33]
ꢀ4.73
ꢀ4.72
ꢀ5.08
ꢀ4.82
ꢀ4.87
–
ꢀ4.93
ꢀ4.67
ꢀ4.88
– no evaluated in the full panel of 60 cell lines.

1588
P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
acetate 8:2): Rf 0.33; IR (nujol):
n
1625,1535,1345 cmꢀ1; UV (EtOH):
8.84 (1H, d, J ¼ 2.4 Hz, H-6),
0.45 mmol), 3,4-dimethoxythiophenol (24) (77 mg, 0.45 mmol) and
lmax 364, 203 nm; 1H NMR (CDCl3):
d
Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 30 min; m.p. 196–198 ꢁC
8.72 (1H, d, J ¼ 2.4 Hz, H-8), 8.42 (2H, dd, J ¼ 1.4 and J ¼ 7 Hz, Ar),
7.68–7.57 (3H, m, Ar), 6.50 (2H, m, Ar), 3.93 (3H, s, CH3), 3.87 (6H, s,
2 ꢃ CH3). GC/MS: m/z 478 [M]þ. Anal. Calcd. for C23H18N4O8: C,
57.74; H, 3.79; N, 11.71; found C, 57.86; H, 3.66; N; 11.60.
4.1.2.2.5. 5,7-Dinitro-3-phenyl-2-[(3,4-dichloro)phenoxy]quinoxa
line (38). This compound was obtained in 98% yield by the protocol
described in the general procedure starting from 8 (150 mg,
0.45 mmol), 3,4-dichlorophenol (20) (73 mg, 0.45 mmol) and
Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 1 h; m.p. 196–198 ꢁC (from
(from CH3CN); TLC (petroleum ether/ethyl acetate 7:3): Rf 0.47; IR
(nujol): n d 8.78–8.70 (2H,
1580, 1530, 1350 cmꢀ1; 1H NMR (CDCl3):
m, H-6, 8), 8.09–8.00 (2H, m, Ar), 7.68–7.55 (3H, m, Ar), 7.16 (1H, dd,
J ¼ 1.4 Hz and J ¼ 8.4 Hz, Ar), 7.01 (1H, d, J ¼ 1.8 Hz, Ar), 7.00 (1H, d,
J ¼ 9.8 Hz, Ar), 3.99 (3H, s, CH3), 3.89 (3H, s, CH3). 13C NMR (CDCl3):
d
56 (2 ꢃ CH3), 111.5 (CH), 115 (CH), 118.2 (CH), 120 (CH), 127.2
(2 ꢃ CH), 128.6 (CH), 129.1 (2 ꢃ CH), 129.5 (CH), 129.8 (CH), 133 (C),
137 (CH), 139.1 (C), 141.5 (C), 148.1 (C), 150 (C), 150.2 (C), 152 (C), 155
(C). GC/MS: m/z 464 [M]þ. Anal. Calcd. for C22H16N4O6S: C, 56.89; H,
3.47; N, 12.06; found C, 56.59; H, 3.97; N, 11.76.
CH4O); TLC (petroleum ether/ethyl acetate 8:2): Rf 0.63; IR (nujol):
1625, 1535, 1345 cmꢀ1; UV (EtOH): lmax 364, 203 nm; 1H NMR
(CDCl3/DMSO-d6):
n
4.1.2.2.10. 5,7-Dinitro-3-phenyl-2-[(3,4-dichloro)phenylthio]quin
oxaline (43). This compound was obtained in 81% yield by the
protocol described in the general procedure starting from 8 (150 mg,
0.45 mmol), 3,4-dichlorothiophenol (25) (81 mg, 0.45 mmol) and
Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 45 min; the compound was
purified by silica gel column chromatographyeluting with a 95:5 and
1:1 mixture of petroleum ether/ethyl acetate; m.p.195–197 ꢁC (from
d
9.02 (1H, d, J ¼ 2.2 Hz, H-6), 8.74 (1H, d,
J ¼ 2.4 Hz, H-8), 8.27 (2H, dd, J ¼ 2.0 and J ¼ 6.6 Hz, Ar), 7.84 (1H, d,
J ¼ 2.6 Hz, Ar), 7.78 (1H, d, J ¼ 8.8 Hz, Ar), 7.69–7.58 (3H, m, Ar), 7.48
(1H, dd, J ¼ 8.8 Hz and J ¼ 2.8 Hz, Ar). GC/MS: m/z 456 [M]þ. Anal.
Calcd. for C20H10Cl2N4O5: C, 52.54; H, 2.20; N, 12.25; found C, 52.33;
H, 2.13; N, 12.23.
4.1.2.2.6. 5,7-Dinitro-3-phenyl-2-[(4-fluoro)phenoxy]quinoxaline
(39). This compound was obtained in 88% yield by the protocol
described in the general procedure starting from 8 (150 mg,
0.45 mmol), 4-fluorophenol (21) (50 mg, 0.45 mmol) and Cs2CO3
(147 mg, 0.45 mmol) at 70 ꢁC for 2 h; m.p. 248–249 ꢁC (from
CH3CN); TLC (petroleum ether/ethyl acetate 8:2): Rf 0.63; IR (nujol):
1570, 1530, 1350 cmꢀ1; UV (EtOH): lmax 366, 203 nm; 1H NMR
(CDCl3/DMSO-d6):
J ¼ 2.4 Hz, H-8), 8.08–7.95 (2H, m, Ar), 7.71 (1H, d, J ¼ 2 Hz, Ar), 7.70–
7.58 (4H, m, Ar), 7.46 (1H, dd, J ¼ 8.4 Hz and J ¼ 2.2 Hz, Ar). GC/MS: m/
z 471 [M]þ. Anal. Calcd. for C20H10Cl2N4O4S: C, 50.75; H, 2.13; N,
11.84; found C, 50.30; H, 2.00; N, 11.70.
4.1.2.2.11. 5,7-Dinitro-3-phenyl-2-[(4-fluoro)phenylthio]quinoxa-
line (44). This compound was obtained in 68% yield by the protocol
described in the general procedure starting from 8 (150 mg,
0.45 mmol), 4-fluorothiophenol (26) (58 mg, 0.45 mmol) and
Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 30 min; m.p. 162–164 ꢁC
(from CH3CN); TLC (petroleum ether/ethyl acetate 8:2): Rf 0.35; IR
n
d
8.79 (1H, d, J ¼ 2.4 Hz, H-6), 8.75 (1H, d,
CH3CN); TLC (cyclohexane/ethyl acetate 9:1): Rf 0.35; IR (nujol):
1580, 1530, 1350 cmꢀ1; UV (EtOH): lmax 308, 236, 226, 203 nm; 1H
NMR (CDCl3/DMSO-d6):
n
d
8.81 (1H, d, J ¼ 2.2 Hz, H-6), 8.74 (1H, d,
J ¼ 2.4 Hz, H-8), 8.50–8.30 (2H, m, Ar), 7.71–7.50 (3H, m, Ar), 7.41–
7.13 (4H, m, Ar). GC/MS: m/z 406 [M]þ. Anal. Calcd. for C20H11FN4O5:
C, 59.12; H, 2.73; N, 13.79; found C, 59.01; H, 2.50; N, 13.58.
4.1.2.2.7. N-[4-(5,7-Dinitro-3-phenylquinoxalin-2-yloxy)benzoyl]
glutamic acid diethyl ester (40) [44]. This compound was obtained
in 50% yield by the protocol described in the general procedure
(nujol):
n
1580, 1530, 1360 cmꢀ1; UV (EtOH): lmax 389, 298, 237,
starting
from
8
(150 mg,
0.45 mmol),
N-[4-(hydrox-
205 nm; 1H NMR (CDCl3):
d 8.71 (2H, s, Ar), 8.10–7.99 (2H, m, Ar),
y)benzoyl]glutamic acid diethyl ester (22) [35] (145 mg,
0.45 mmol) and Cs2CO3 (147 mg, 0.45 mmol) under a N2 atmo-
sphere at room temperature for 9 h and 45 min; m.p. 227–228 ꢁC
(from C2H6O); TLC (petroleum ether/ethyl acetate 6:4): Rf 0.41; IR
7.70–7.50 (5H, m, Ar), 7.30–7.18 (2H, m, Ar). GC/MS: m/z 422 [M]þ.
Anal. Calcd. for C20H11FN4O4S: C, 56.87; H, 2.62; N, 13.26; found C,
56.60; H, 2.43; N, 13.00.
(nujol):
n
3320, 1745, 1640, 1600, 1540, 1350 cmꢀ1; 1H NMR (CDCl3):
4.1.2.3. N-[4(5,7-Dinitro-3-phenylquinoxalin-2-ylthio)-benzoyl]gluta
mic acid diethyl ester (46). Compound 45 (304 mg, 0.45 mmol),
prepared as previously reported in the literature [36,37] was
reduced in absolute EtOH (5 mL) with NaBH4 (33 mg, 0.9 mmol) at
room temperature. When the reduction was completed (30 min),
5,7-dinitro-3-phenyl-2-chloroquinoxaline (8) [33] (298 mg,
0.9 mmol) in 3 mL was added. The mixture was stirred under a N2
atmosphere at room temperature for 1 h. After removal of the
solvent in vacuo, the residue was suspended inwater (22 mL) and the
solid residue was collected by filtration and purified by flash chro-
matography over silica gel eluting with a 7:3 mixture of petroleum
ether/ethyl acetate (31% yield); m.p. 160–161 ꢁC (from C3H8O); TLC
d
8.81–8.75 (2H, m, H-6, 8), 8.42 (2H, dd, J ¼ 6 Hz and J ¼ 2.4 Hz, Ar),
8.02 (2H, d, J ¼ 8.8 Hz, Ar), 7.66–7.55 (3H, m, Ar), 7.35 (2H, d,
J ¼ 8.8 Hz, Ar), 7.23 (1H, d, J ¼ 7.4 Hz, exc. with H2O, CONH), 4.90–
4.78 (1H, m, CH), 4.28 (2H, q, J ¼ 7.2 Hz, CH2), 4.15 (2H, q, J ¼ 7.2 Hz,
CH2), 2.60–2.10 (4H, m, CH2CH2), 1.30 (3H, t, J ¼ 7.2 Hz, CH3), 1.22
(3H, t, J ¼ 7.2 Hz, CH3). 13C NMR (CDCl3):
d
14 (2 ꢃ CH3), 26.3 (CH2),
30.4 (CH2), 52.5 (CH), 61.2 (2 ꢃ CH2), 118 (CH), 121.3 (2 ꢃ CH), 127.4
(2 ꢃ CH),128.2 (CH),128.4 (2 ꢃ CH),128.7 (CH),129.1 (2 ꢃ CH),130.1
(C), 131.5 (C), 132 (C), 139.5 (C), 142.5 (C), 144 (C), 151 (C), 158.3 (C),
167.5 (C), 171.4 (C), 173 (C), 176 (C). GC/MS: m/z 617 [M]þ. Anal.
Calcd. for C30H27N5O10: C, 58.35; H, 4.41; N,11.34; found C, 58.66; H,
4.47; N, 11.13.
(petroleum ether/ethyl acetate 1:1): Rf 0.40; IR (nujol):
1640, 1530, 1350 cmꢀ1; UV (EtOH): lmax 388, 222, 201 nm; 1H NMR
(CDCl3): 8.73 (2H, s, H-6, 8), 8.10–8.00 (2H, m, Ar), 7.97 (2H, d,
n 3300, 1720,
4.1.2.2.8. 5,7-Dinitro-3-phenyl-2-[(4-methoxy)phenylthio]quinox
aline (41). This compound was obtained in 96% yield by the
protocol described in the general procedure starting from 8
(150 mg, 0.45 mmol), 4-methoxythiophenol (23) (63 mg,
0.45 mmol) and Cs2CO3 (147 mg, 0.45 mmol) at 70 ꢁC for 2 h; m.p.
192–193 ꢁC (from CH3CN); TLC (petroleum ether/ethyl acetate 8:2):
d
J ¼ 8.2 Hz, Ar), 7.66 (2H, d, J ¼ 8.2 Hz, Ar), 7.65–7.58 (3H, m, Ar), 4.82–
4.79 (1H, m, OCH–CH2), 4.28 (2H, q, CH2CH3), 4.15 (2H, q, CH2CH3),
2.70–2.10 (4H, m, CH2CH2),1.30 (3H, t, CH2CH3),1.25 (3H, t, CH2CH3).
13C NMR (CDCl3):
d
14.2 (2 ꢃ CH3), 26.4 (CH2), 30.3 (CH2), 52.5 (CH),
Rf 0.53; IR (nujol):
n
1625, 1535, 1345 cmꢀ1; UV (EtOH): lmax 366,
61.1 (2 ꢃ CH2), 121 (CH), 127.3 (2 ꢃ CH), 127.6 (2 ꢃ CH), 128.5 (CH),
129.8 (CH),129.4 (2 ꢃ CH),129.1 (2 ꢃ CH),131 (C),133 (C),135 (C),137
(C), 139.2 (C), 141.6 (C), 148 (C), 150.2 (C), 152 (C), 167.5 (C), 171.5 (C),
173.2 (C). GC/MS: m/z 633 [M]þ. Anal. Calcd. for C30H27N5O9S: C,
56.87; H, 4.30; N, 11.05; found C, 56.51; H, 4.08; N, 10.88.
203 nm; 1H NMR (CDCl3):
d
8.71 (1H, d, J ¼ 2.2 Hz, H-6), 8.69 (1H, d,
J ¼ 2.4 Hz, H-8), 8.10–8.00 (2H, m, Ar), 7.70–7.55 (3H, m, Ar), 7.46
(2H, d, J ¼ 8.8 Hz, Ar), 7.03 (2H, d, J ¼ 8.8 Hz, Ar), 3.91 (3H, s, CH3).
GC/MS: m/z 434 [M]þ. Anal. Calcd. for C21H14N4O5S: C, 58.06; H,
3.25; N, 12.90; found C, 57.98; H, 3.15; N, 12.70.
4.1.2.2.9. 5,7-Dinitro-3-phenyl-2-[(3,4-dimethoxy)phenylthio]qui
noxaline (42) [44]. This compound was obtained in 81% yield by the
protocol described in the general procedure starting from 8 (150 mg,
4.1.2.4. General procedure for preparation of 5,7-diamino-quinoxa-
lines 1–3b, 5–7b, 1–5c, 7c and 1–5d. A mixture of 27–29, 31–38,
40–44 and 46 (0.28–0.82 mmol) and an excess of hydrazine hydrate

P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
1589
(2.40–12.3 mmol) in ethanol (12–181 mL) in the presence of 10%
palladised charcoal was refluxed for the time reported below. The
desired compounds were obtained by filtration of the palladised
charcoal and evaporation in vacuo of the solvent. The crude solids
were purified either by recrystallization or by flash chromatog-
raphy over silica gel as reported below.
protocol described in the general procedure starting from 32
(200 mg, 0.48 mmol), hydrazine hydrate (360 mg, 7.2 mmol) and
palladised charcoal (20 mg) in ethanol (25 mL) after 10 min under
reflux; m.p. 82–85 ꢁC (from CH4O þ H2O); TLC (petroleum ether/
ethyl acetate 6:4): Rf 0.42; IR (nujol):
n
3440, 3340, 1610 cmꢀ1; UV
(EtOH): lmax 382, 296, 270, 226, 204 nm; 1H NMR (CDCl3):
d 7.69
4.1.2.4.1. 5,7-Diamino-3-phenyl-2-[(4-methoxy-benzyl)amino]qui
noxaline (1b). This compound was obtained in 97% yield by the
protocol described in the general procedure starting from 27
(340 mg, 0.8 mmol), hydrazine hydrate (320 mg, 6.4 mmol) and
palladised charcoal (34 mg) in ethanol (181 mL) after 1 h and
35 min under reflux; m.p. 74–77 ꢁC (from CH4O þ H2O); TLC
(2H, dd, J ¼ 7.8 Hz and J ¼ 1.6 Hz, Ar), 7.58–7.40 (3H, m, Ar), 7.48–
7.22 (2H, m, Ar), 7.18–6.90 (2H, t, Ar), 6.31 (1H, d, J ¼ 2.2 Hz, H-8),
6.08 (1H, d, J ¼ 2.2 Hz, H-6), 5.30 (1H, t, exc. with D2O, NH–CH2),
4.69 (2H, d, CH2). LC/MS: m/z 360 [M þ H]. Anal. Calcd. for
C21H18FN5: C, 70.18; H, 5.05; N, 19.49; found C, 70.00; H, 4.96; N,
19.39.
(petroleum ether/ethyl acetate 4:6): Rf 0.40; IR (nujol):
3350, 1630 cmꢀ1; UV (EtOH): lmax 359, 332, 285 nm; 1H NMR
(CDCl3):
n
3420,
4.1.2.4.6. N-[4-[(5,7-Diamino-3-phenylquinoxalin-2-ylamino)me-
thyl]benzoyl]glutamic acid diethyl ester (7b) [44]. This compound
was obtained in 78% yield by the protocol described in the general
procedure starting from 33 (150 mg, 0.24 mmol), hydrazine hydrate
(180 mg, 3.6 mmol) and palladised charcoal (15 mg) in ethanol
(16 mL) after 10 min under reflux; m.p. 72–75 ꢁC (from
C3H8O þ H2O); TLC (petroleum ether/ethyl acetate 3:7): Rf 0.36; IR
d
7.69 (2H, dd, J ¼ 8 Hz and J ¼ 1.8 Hz, Ar), 7.51–7.40 (3H, m,
Ar), 7.28 (2H, d, J ¼ 8.4 Hz, Ar), 6.85 (2H, d, J ¼ 8.6 Hz, Ar), 6.33 (1H,
d, J ¼ 2.2 Hz, H-8), 6.10 (1H, d, J ¼ 2.2 Hz, H-6), 5.24 (2H, t, exc. with
D2O, NH–CH2), 4.66 (2H, d, NH–CH2), 3.78 (3H, s, OCH3). GC/MS: m/
z 371 [M]þ. Anal. Calcd. for C22H21N5O: C, 71.14; H, 5.70; N, 18.85;
found C, 71.00; H, 5.22; N, 18.60.
(nujol):
7.81 (2H, d, J ¼ 8 Hz, Ar), 7.71 (2H, dd, J ¼ 8.2 Hz and J ¼ 2 Hz, Ar),
n ;
3460, 3340, 1735, 1640, 1600 cmꢀ1 1H NMR (CDCl3):
4.1.2.4.2. 5,7-Diamino-3-phenyl-2-[(3,5-dimethoxy-benzyl)amino
]quinoxaline (2b). This compound was obtained in 77% yield by the
protocol described in the general procedure starting from 28
(150 mg, 0.32 mmol), hydrazine hydrate (130 mg, 2.6 mmol) and
palladised charcoal (15 mg) in ethanol (70 mL) after 2 h under
reflux; m.p. 161–163 ꢁC (from CH4O þ H2O); TLC (petroleum ether/
d
7.48–7.41 (3H, m, Ar), 7.42 (2H, d, J ¼ 8.4 Hz, Ar), 7.01 (1H, d,
J ¼ 7.2 Hz, exc. with D2O, CONH), 6.28 (1H, d, J ¼ 2.2 Hz, H-8), 6.08
(1H, d, J ¼ 2.2 Hz, H-6), 5.36 (1H, t, exc. with D2O, NH), 4.82–4.64
(1H, m, CH), 4.78 (2H, d, CH2), 4.23 (2H, q, CH2), 4.10 (2H, q, CH2),
3.88 (2H, br s, exc. with D2O, NH2), 2.61–2.41 (4H, m, CH2CH2), 1.30
(3H, t, J ¼ 7.2 Hz, CH3), 1.21 (3H, t, J ¼ 7.2 Hz, CH3). 13C NMR (CDCl3):
ethyl acetate 6:4): Rf 0.31; IR (nujol):
n
3440, 3340, 1610 cmꢀ1; UV
7.71
(EtOH): lmax 382, 296, 270, 226, 204 nm; 1H NMR (CDCl3):
d
d
14.0 (2 ꢃ CH3), 26.3 (CH2), 30.3 (CH2), 43.1 (CH2), 52.1 (CH), 61.2
(2H, dd, J ¼ 7.8 Hz and J ¼ 1.8 Hz, Ar), 7.56–7.42 (3H, m, Ar), 6.51
(2H, d, J ¼ 2.2 Hz, Ar), 6.37–6.30 (2H, m, Ar), 6.10 (1H, d, J ¼ 2.4 Hz,
H-8), 5.30 (1H, t, exc. with D2O, NH), 4.68 (2H, d, CH2), 3.76 (6H, s,
2 ꢃ OCH3). GC/MS: m/z 401 [M]þ. Anal. Calcd. for C23H23N5O2: C,
68.81; H, 5.77; N, 17.44; found C, 68.74; H, 5.53; N, 17.24.
(2 ꢃ CH2), 98 (CH), 117 (C), 125.3 (CH),127.0 (2 ꢃ CH), 127.2 (2 ꢃ CH),
127.4 (2 ꢃ CH), 128.5 (CH), 129.1 (2 ꢃ CH), 130 (C), 132.2 (C), 135.3
(C), 141 (C), 142.5 (C), 143.3 (C), 145 (C), 149.6 (C), 167.5 (C), 171.5 (C),
173.1 (C). GC/MS: m/z 570 [M]þ. Anal. Calcd. for C31H34N6O5: C,
65.25; H, 6.01; N, 14.73; found: C, 65.03; H, 45.95; N, 14.54.
4.1.2.4.3. 5,7-Diamino-3-phenyl-2-[(3,4-dimethoxy-benzyl)amino
]quinoxaline (3b) [44]. This compound was obtained in 61% yield by
the protocol described in the general procedure starting from 29
(150 mg, 0.32 mmol), hydrazine hydrate (240 mg, 4.8 mmol) and
palladised charcoal (15 mg) in ethanol (21 mL) after 30 min under
reflux; m.p. 105–108 ꢁC (from C2H6O); TLC (petroleum ether/ethyl
4.1.2.4.7. 5,7-Diamino-3-phenyl-2-[(4-methoxy)phenoxy]quinoxa
line (1c). This compound was obtained in 92% yield by the protocol
described in the general procedure starting from 34 (290 mg,
0.69 mmol), hydrazine hydrate (311 mg, 6.2 mmol) and palladised
charcoal (29 mg) in ethanol (160 mL) after 5 h and 15 min under
reflux; m.p. 189–191 ꢁC (from CH4O þ H2O); TLC (petroleum ether/
acetate 3:7): Rf 0.36; IR (nujol):
(CDCl3):
n
3420, 3340, 1610 cmꢀ1
;
1H NMR
ethyl acetate 1:1): Rf 0.35; IR (nujol):
n
3440, 3340, 1610 cmꢀ1; UV
8.15
d
7.71 (2H, dd, J ¼ 8.0 Hz and J ¼ 2 Hz, Ar), 7.53–7.41 (3H, m,
(EtOH): lmax 382, 296, 270, 226, 204 nm; 1H NMR (CDCl3):
d
Ar), 6.92 (1H, d, J ¼ 3 Hz, Ar), 6.90 (1H, dd, J ¼ 8.0 Hz and J ¼ 2.0 Hz,
Ar), 6.80 (1H, d, J ¼ 8 Hz, Ar), 6.33 (1H, d, J ¼ 2.4 Hz, H-8), 6.08 (1H,
d, J ¼ 2.4 Hz, H-6), 5.26 (1H, t, exc. with D2O, NH), 4.73 (2H, br s, exc.
with D2O, NH2), 4.66 (2H, d, CH2), 3.88 (2H, br s, exc. with D2O,
(2H, dd, J ¼ 7.8 Hz and J ¼ 1.6 Hz, Ar), 7.55–7.39 (3H, m, Ar), 7.13 (2H,
d, J ¼ 9 Hz, Ar), 6.93 (2H, d, J ¼ 9 Hz, Ar), 6.26 (1H, d, J ¼ 2.2 Hz, H-8),
6.06 (1H, d, J ¼ 2.2 Hz, H-6), 5.38 (2H, br s, exc. with D2O, NH2), 4.90
(2H, br s, exc. with D2O, NH2), 3.83 (3H, s, OCH3). LC/MS: m/z 359
[M þ H]. Anal. Calcd. for C21H18N4O2: C, 70.38; H, 5.06; N, 15.63;
found C, 70.01; H, 4.96; N, 15.23.
NH2), 3.86 (3H, s, OCH3), 3.85 (3H, s, OCH3). 13C NMR (CDCl3):
d 43.3
(CH2), 56.0 (2 ꢃ CH3), 98 (CH), 109.1 (CH), 112.1 (CH), 118 (C), 120.1
(CH), 125.0 (CH), 127.4 (2 ꢃ CH), 128.6 (CH), 129.0 (2 ꢃ CH), 131 (C),
133.3 (C), 135.0 (C), 141 (C), 142.5 (C), 145 (C), 147.6 (C), 149.3 (C),
149.7 (C). GC/MS: m/z 401 [M]þ. Anal. Calcd. for C23H23N5O2: C,
68.81; H, 5.77; N, 17.44; found C, 68.72; H, 5.54; N, 17.15.
4.1.2.4.8. 5,7-Diamino-3-phenyl-2-[(3,5-dimethoxy)phenoxy]quin
oxaline (2c). This compound was obtained in 71% yield by the
protocol described in the general procedure starting from 35
(360 mg, 0.8 mmol), hydrazine hydrate (320 mg, 6.4 mmol) and
palladised charcoal (36 mg) in ethanol (181 mL) after 1 h; m.p. 159–
160 ꢁC (from CH4O þ H2O); TLC (petroleum ether/ethyl acetate
4.1.2.4.4. 5,7-Diamino-3-phenyl-2-[(3,4-dichloro-benzyl)amino]q
uinoxaline (5b). This compound was obtained in 38% yield by the
protocol described in the general procedure starting from 31
(300 mg, 0.64 mmol), hydrazine hydrate (480 mg, 9.6 mmol) and
palladised charcoal (30 mg) in ethanol (32 mL) after 10 min under
reflux; m.p. 81–84 ꢁC (from CH4O þ H2O); TLC (petroleum ether/
4:6): Rf 0.49; IR (nujol):
lmax 379, 295, 270, 226, 204 nm; 1H NMR (CDCl3):
n
3420, 3320, 1610, 1220 cmꢀ1; UV (EtOH):
d
8.15 (2H, dd,
J ¼ 6.4 Hz and J ¼ 1.2 Hz, Ar), 7.57–7.42 (3H, m, Ar), 6.41 (2H, d,
J ¼ 2.2 Hz, Ar), 6.35 (1H, d, J ¼ 2.2 Hz, Ar), 6.31 (1H, d, J ¼ 2.2 Hz, H-
6), 6.24 (1H, d, J ¼ 2.2 Hz, H-8), 5.38 (2H, br s, exc. with D2O, NH2),
4.90 (2H, br s, exc. with D2O, NH2), 3.78 (6H, s, 2 ꢃ OCH3). LC/MS: m/
z 389 [M þ H]. Anal. Calcd. for C22H20N4O3: C, 68.03; H, 5.19; N,
14.42; found C, 67.98; H, 5.00; N, 14.22.
4.1.2.4.9. 5,7-Diamino-3-phenyl-2-[(3,4-dimethoxy)phenoxy]quin
oxaline (3c) [44]. This compound was obtained in 69% yield by the
protocol described in the general procedure starting from 36
(300 mg, 0.7 mmol), hydrazine hydrate (526 mg, 10.5 mmol) and
palladised charcoal (30 mg) in ethanol (25 mL) after 20 min; m.p.
ethyl acetate 5:5): Rf 0.36; IR (nujol):
n
3440, 3340, 1610 cmꢀ1; UV
7.70 (2H,
(EtOH): lmax 382, 296, 270, 226, 204 nm; 1H NMR (CDCl3):
d
dd, J ¼ 8.0 Hz and J ¼ 1.6 Hz, Ar), 7.60–7.42 (3H, m, Ar), 7.40–7.10 (3H,
m, Ar), 6.28 (1H, d, J ¼ 2.4 Hz, H-8), 6.08 (1H, d, J ¼ 2.2 Hz, H-6), 5.28
(1H, t, exc. with D2O, NH), 4.67 (2H, d, CH2), 3.90–3.80 (2H, br s, exc.
with D2O, NH2). LC/MS: m/z 410 [M þ H]. Anal. Calcd. for C21H17Cl2N5:
C, 61.47; H, 4.18; N, 17.07; found C, 61.32; H, 4.01; N, 16.90.
4.1.2.4.5. 5,7-Diamino-3-phenyl-2-[(4-fluoro-benzyl)amino]quino
xaline (6b). This compound was obtained in 22% yield by the

1590
P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
195–198 ꢁC (from CH4O þ H2O); TLC (petroleum ether/ethyl acetate
(EtOH): lmax 284, 257, 229, 202 nm; 1H NMR (CDCl3):
d 8.45 (2H, br
4:6): Rf 0.31; IR (nujol):
n
3440, 3380, 1610 cmꢀ1; 1H NMR (CDCl3):
s, exc. with D2O, NH2), 8.05 (1H, s, H-8), 7.98 (1H, s, H-6), 7.95–7.85
(2H, m, Ar), 7.68–7.55 (3H, m, Ar), 7.46 (2H, dd, J ¼ 2.8 Hz, Ar), 7.00
(2H, d, J ¼ 8.8 Hz, Ar), 5.62 (2H, br s, exc. with D2O, NH2), 3.90 (3H, s,
OCH3). LC/MS: m/z 375 [M þ H]. Anal. Calcd. for C21H18N4OS: C,
67.36; H, 4.85; N, 14.96; found C, 67.25; H, 4.66; N, 14.78.
d
8.19 (2H, dd, J ¼ 8.2 Hz and J ¼ 1.8 Hz, Ar), 7.57–7.40 (3H, m, Ar),
6.90 (1H, d, J ¼ 9.4 Hz, Ar), 6.83–6.75 (2H, m, Ar), 6.25 (1H, d,
J ¼ 2.2 Hz, H-8), 6.21 (1H, d, J ¼ 2.2 Hz, H-6), 4.91 (2H, br s, exc. with
D2O, NH2), 3.94 (3H, s, OCH3), 3.86 (3H, s, OCH3). 13C NMR (CDCl3):
d
56.3 (CH3), 101 (CH), 108.4 (CH), 115.9 (CH), 116.2 (CH), 120 (C),
4.1.2.4.14. 5,7-Diamino-3-phenyl-2-[(3,4-dimethoxy)phenylthio]q
uinoxaline (2d) [44]. This compound was obtained in 33% yield by
the protocol described in the general procedure starting from 42
(210 mg, 0.45 mmol), hydrazine hydrate (338 mg, 6.7 mmol) and
palladised charcoal (21 mg) in ethanol (50 mL) 30 min; m.p. 192–
195 ꢁC (from CH3CN); TLC (petroleum ether/ethyl acetate 6:4): Rf
126.9 (CH), 127.4 (2 ꢃ CH), 128.7 (2 ꢃ CH), 129.2 (2 ꢃ CH), 130 (C),
131.6 (C),142 (C), 143.6 (C), 145.7 (C),147 (C), 148.3 (C), 150.8 (C), 170
(C). LC/MS: m/z 389 [M þ H]. Anal. Calcd. for C22H20N4O3: C, 68.03;
H, 5.19; N, 14.42; found C, 67.98; H, 5.00; N, 14.22.
4.1.2.4.10. 5,7-Diamino-3-phenyl-2-[(3,4,5-trimethoxy)phenoxy]q
uinoxaline (4c). This compound was obtained in 65% yield by the
protocol described in the general procedure starting from 37
(350 mg, 0.7 mmol), hydrazine hydrate (526 mg, 10.5 mmol) and
palladised charcoal (35 mg) in ethanol (26 mL) after 10 min; m.p.
203–205 ꢁC (from CH4O); TLC (petroleum ether/ethyl acetate 4:6):
0.43; IR (nujol):
n ; d 8.98
3400, 3380, 1580 cmꢀ1 1H NMR (CDCl3):
(2H, s, exc. with D2O, NH2), 8.49 (2H, br s, exc. with D2O, NH2), 8.00–
7.88 (4H, m, Ar), 7.58–7.44 (3H, m, Ar), 7.18 (1H, dd, J ¼ 8.4 Hz and
J ¼ 2 Hz, Ar), 7.03 (1H, d, J ¼ 1.8 Hz, Ar), 6.98 (1H, d, J ¼ 9.8 Hz, Ar),
3.96 (3H, s, CH3), 3.87 (3H, s, CH3). 13C NMR (CDCl3):
d 56.0
Rf 0.35; IR (nujol):
n
3420, 3320, 1610, 1220 cmꢀ1; UV (EtOH): lmax
8.17 (2H, dd,
(2 ꢃ CH3), 103 (CH), 111.6 (CH), 115.0 (CH), 118.2 (CH), 126 (C), 127.3
(2 ꢃ CH), 128.4 (CH), 128.7 (CH), 129.2 (2 ꢃ CH), 129.9 (CH), 133.0
(C), 139 (C), 142.7 (C), 143 (C), 144 (C), 147 (C), 150.1 (C), 155.3 (C).
GC/MS: m/z 404 [M]þ. Anal. Calcd. for C22H20N4O2S: C, 65.33; H,
4.98; N, 13.85; found C, 65.23; H, 4.76; N, 13.64.
379, 295, 269, 223, 204 nm; 1H NMR (CDCl3):
d
J ¼ 8.4 Hz and J ¼ 2 Hz, Ar), 7.57–7.40 (3H, m, Ar), 6.49 (2H, s, Ar),
6.29 (1H, d, J ¼ 2.4 Hz, H-8), 6.24 (1H, d, J ¼ 2.4 Hz, H-6), 4.93 (2H, br
s, exc. with D2O, NH2), 3.98 (2H, br s, exc. with D2O, NH2), 3.87 (3H,
s, OCH3), 3.83 (6H, s, 2 ꢃ OCH3). GC/MS: m/z 418 [M]þ. Anal. Calcd.
for C23H22N4O4: C, 66.02; H, 5.30; N, 13.39; found C, 65.97; H, 5.35;
N, 13.15.
4.1.2.4.15. 5,7-Diamino-3-phenyl-2-[(3,4-dichloro)phenylthio]qui
noxaline (3d). This compound was obtained in 61% yield by the
protocol described in the general procedure starting from 43
(150 mg, 0.32 mmol), hydrazine hydrate (240 mg, 4.8 mmol) and
palladised charcoal (15 mg) in ethanol (40 mL) after 30 min; m.p.
178–180 ꢁC (from CH4O þ H2O); TLC (petroleum ether/ethyl acetate
4.1.2.4.11. 5,7-Diamino-3-phenyl-2-[(3,4-dichloro)phenoxy]quino
xaline (5c). This compound was obtained in 86% yield by the
protocol described in the general procedure starting from 38
(150 mg, 0.33 mmol), hydrazine hydrate (248 mg, 4.95 mmol) and
palladised charcoal (15 mg) in ethanol (12 mL) after 10 min; m.p.
178–180 ꢁC (from CH4O þ H2O); TLC (petroleum ether/ethyl acetate
7:3): Rf 0.38; IR (nujol):
286, 252, 204 nm; 1H NMR (CDCl3/DMSO-d6):
n
3500, 3300, 1600 cmꢀ1; UV (EtOH): lmax
d
9.03 (2H, br s, exc.
with D2O, NH2), 8.52 (2H, br s, exc. with D2O, NH2), 7.96 (2H, s, Ar),
7.95–7.81 (2H, m, Ar), 7.68 (1H, d, J ¼ 2 Hz, Ar), 7.69–7.50 (3H, m,
Ar), 7.58 (1H, d, J ¼ 8.6 Hz, Ar), 7.42 (1H, dd, J ¼ 8.8 Hz and J ¼ 1.8 Hz,
Ar). LC/MS: m/z 413 [M þ H]. Anal. Calcd. for C20H14Cl2N4S: C, 58.12;
H, 3.41; N, 13.56; found C, 58.02; H, 3.23; N, 13.35.
5:5): Rf 0.57; IR (nujol):
379, 293, 268, 223, 206 nm; 1H NMR (CDCl3):
n
3420, 3320, 1610 cmꢀ1; UV (EtOH): lmax
d
8.11 (2H, dd,
J ¼ 1.8 Hz and J ¼ 7.8 Hz, Ar), 7.58–7.42 (4H, m, Ar), 7.39 (1H, d,
J ¼ 2.4 Hz, Ar), 7.11 (1H, dd, J ¼ 2.8 Hz and J ¼ 8.8 Hz, Ar), 6.24 (2H, s,
Ar), 4.93 (2H, br s, exc. with D2O, NH2), 4.00 (2H, br s, exc. with D2O,
NH2). LC/MS: m/z 397 [M þ H]. Anal. Calcd. for C20H14Cl2N4O: C,
60.47; H, 3.55; N, 14.10; found C, 60.20; H, 3.86; N, 13.86.
4.1.2.4.12. N-[4-(5,7-Diamino-3-phenylquinoxalin-2-yloxy)benzo
yl]glutamic acid diethyl ester (7c) [44]. This compound was
obtained in 74% yield by the protocol described in the general
procedure starting from 40 (300 mg, 0.48 mmol), hydrazine
hydrate (360 mg, 7.2 mmol) and palladised charcoal (30 mg) in
ethanol (32 mL) after 30 min; m.p. 178–181 ꢁC (from CH4O); TLC
4.1.2.4.16. 5,7-Diamino-3-phenyl-2-[(4-fluoro)phenylthio]quinox
aline (4d). This compound was obtained in 54% yield by the protocol
described in the general procedure starting from 44 (150 mg,
0.35 mmol), hydrazine hydrate (260 mg, 5.2 mmol) and palladised
charcoal (15 mg) in ethanol (85 mL) after 3 h; m.p.163–165 ꢁC (from
CH4O þ H2O); TLC (petroleum ether/ethyl acetate 7:3): Rf 0.45; IR
(nujol):
203 nm; 1H NMR (CDCl3):
n
3410, 3300, 1590 cmꢀ1; UV (EtOH): lmax 370, 279, 246,
d
8.10–8.00 (2H, m, Ar), 8.00–7.84 (2H, m,
Ar), 7.71–7.50 (5H, m, Ar), 7.28–7.11 (2H, m, Ar), 4.80 (2H, br s, exc.
with D2O, NH2). LC/MS: m/z 363 [M þ H]. Anal. Calcd. for C20H15FN4S:
C, 66.28; H, 4.17; N, 15.46; found C, 66.04; H, 4.00; N, 15.37.
(petroleum ether/ethyl acetate 4:6): Rf 0.30; IR (nujol):
n 3420,
3320, 1740, 1635, 1600 cmꢀ1 1H NMR (CDCl3):
;
d
8.14 (2H, dd,
J ¼ 8.2 Hz and J ¼ 2.6 Hz, Ar), 7.89 (2H, d, J ¼ 8.8 Hz, Ar), 7.59–7.40
(3H, m, Ar), 7.30 (2H, d, J ¼ 8.8 Hz, Ar), 7.09 (1, d, J ¼ 7.4 Hz, exc. with
H2O, CONH), 6.26–6.20 (2H, m, H-8, 6), 4.94 (2H, br s, exc. with H2O,
NH2), 4.84–4.68 (1H, m, CH), 4.25 (2H, q, J ¼ 7.2 Hz, CH2), 4.13 (2H,
q, J ¼ 7.2 Hz, CH2), 3.99 (2H, br s, exc. with H2O, NH2), 2.64–2.00
(4H, m, CH2CH2), 1.32 (3H, t, J ¼ 7.2 Hz, CH3), 1.25 (3H, t, J ¼ 7.2 Hz,
4.1.2.4.17. N-[4(5,7-Diamino-3-phenylquinoxalin-2-ylthio)-benzo
yl]glutamic acid diethyl ester (5d) [44]. This compound was
obtained in 56% yield by the protocol described in the general
procedure starting from 46 (180 mg, 0.28 mmol), hydrazine
hydrate (210 mg, 4.2 mmol) and palladised charcoal (18 mg) in
ethanol (20 mL) after 45 min; m.p. 103–105 ꢁC (from CH4O þ H2O);
CH3). 13C NMR (CDCl3):
d
14.0 (2 ꢃ CH3), 26.3 (CH2), 30.5 (CH2), 52.7
TLC (petroleum ether/ethyl acetate 1:1): Rf 0.51; IR (nujol): n 3400,
(CH), 61.3 (2 ꢃ CH2), 102 (CH), 120 (C), 121.6 (2 ꢃ CH), 126.3 (CH),
127.5 (2 ꢃ CH), 128.5 (2 ꢃ CH), 128.7 (CH), 129.2 (2 ꢃ CH), 130 (C),
130.4 (C), 131.6 (C), 143 (C), 143.6 (C), 147 (C), 158.3 (C), 167.5 (C), 171
(C), 171.5 (C), 173.0 (C). GC/MS: m/z 557 [M]þ. Anal. Calcd. for
C30H31N5O6: C, 64.62; H, 5.60; N, 12.56; found C, 64.41; H, 5.35; N,
12.43.
3300, 1720, 1630 cmꢀ1; UV (EtOH): lmax 288, 224, 203 nm; 1H NMR
(CDCl3): 8.50 (2H, br s, exc. with D2O, NH2), 8.08–7.98 (2H, m, Ar),
d
7.92 (2H, J ¼ 8.4 Hz, Ar), 7.91–7.85 (2H, m, Ar), 7.65 (2H, d, J ¼ 8.4 Hz,
Ar), 7.64–7.58 (3H, m, Ar), 7.24 (1H, d, exc. with D2O, CONH), 5.94
(2H, br s, exc. with D2O, NH2), 4.81–4.91 (1H, m, CH), 4.27 (2H, q,
CH2CH3), 4.14 (2H, q, CH2CH3), 2.61–2.10 (4H, m, CH2CH2), 1.33 (3H,
4.1.2.4.13. 5,7-Diamino-3-phenyl-2-[(4-methoxy)phenylthio]quin
oxaline (1d). This compound was obtained in 54% yield by the
protocol described in the general procedure starting from 41
(150 mg, 0.34 mmol), hydrazine hydrate (135 mg, 2.7 mmol) and
palladised charcoal (15 mg) in ethanol (50 mL) after 8 h and
30 min; m.p.162–163 ꢁC (from CH4O þ H2O); TLC (petroleum ether/
t, CH2CH3), 1.25 (3H, t, CH2CH3). 13C NMR (CDCl3):
d
14.0 (2 ꢃ CH3),
26.6 (CH2), 30.4 (CH2), 52.7 (CH), 61.2 (2 ꢃ CH2), 104 (CH), 125 (C),
127.5 (2 ꢃ CH2), 127.8 (2 ꢃ CH), 128.2 (CH), 128.7 (CH), 129.1
(2 ꢃ CH), 129.7 (2 ꢃ CH), 131 (C), 134 (C), 135 (C), 138 (C), 142.7 (C),
143 (C),145 (C),146 (C), 167.5 (C),171.2 (C), 173.1 (C). LC/MS: m/z 574
[M þ H]. Anal. Calcd. for C30H31N5O5S: C, 62.81; H, 5.45; N, 12.21;
found C, 62.52; H, 5.23; N, 12.00.
ethyl acetate 7:3): Rf 0.41; IR (nujol):
n
3480, 3300, 1600 cmꢀ1; UV

P. Corona et al. / European Journal of Medicinal Chemistry 44 (2009) 1579–1591
1591
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in 100 mL of ethanol followed by the addition of 30 mg of 10%
palladised charcoal. This mixture was hydrogenated at 3 atm for 1 h
and 30 min. After filtering and washing the catalyst thoroughly
with ethanol, the filtrate was concentrated in vacuo. The crude
residue was then purified by flash chromatography over silica gel
eluting with 3:7 petroleum ether/ethyl acetate (65% yield); m.p.
61–63 ꢁC (from CH4O þ H2O); TLC (petroleum ether/ethyl acetate
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4:6): Rf 0.46; IR (nujol):
n
3420, 3300, 1600 cmꢀ1; UV (EtOH): lmax
7.71 (2H, dd, J ¼ 8 Hz and
287, 223, 203 nm; 1H NMR (CDCl3):
d
J ¼ 4.2 Hz, Ar), 7.58 (3H, m, Ar), 6.60 (2H, s, Ar), 6.32 (1H, d,
J ¼ 2.4 Hz, H-8), 6.08 (1H, d, J ¼ 2.4 Hz, H-6), 5.28 (1H, t, exc. with
D2O, NH), 4.67 (2H, d, CH2), 3.82 (9H, s, 3 ꢃ OCH3). LC/MS: m/z 432
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found C, 66.70; H, 5.76; N, 16.03.
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4.1.2.6. 5,7-Diamino-3-phenyl-2-[(4-fluoro)phenoxy]quinoxaline (6c).
Compound 39 (200 mg, 0.49 mmol) was dissolved in 100 mL of
ethanol followed by the addition of 20 mg of 10% palladised charcoal.
This mixture was hydrogenated at 3 atm for 1 h and 30 min. After
filtering and washing the catalyst thoroughly with ethanol, the filtrate
was concentrated in vacuo. Then the crude residue was purified by
flash chromatography over silica gel eluting 1:1 petroleum ether/
ethyl acetate (59% yield); m.p. 141–144 ꢁC (from CH4O þ H2O); TLC
(petroleum ether/ethyl acetate 1:1): Rf 0.36; IR (nujol):
n
3420, 3300,
8.17
1600 cmꢀ1; UV (EtOH): lmax 287, 223, 203 nm; 1H NMR (CDCl3):
d
(2H, dd, J ¼ 8.2 Hz and J ¼ 2.4 Hz, Ar), 7.58–7.38 (3H, m, Ar), 7.23–7.00
(4H, m, Ar), 6.22 (2H, s, H-6, 8), 4.91 (2H, br s, exc. with D2O, NH2), 3.94
(2H, br s, exc. with D2O, NH2). LC/MS: m/z 347 [M þ H]. Anal. Calcd. for
C20H15FN4O: C, 69.35; H, 4.37; N, 16.18; found C, 69.25; H, 4.20; N,
16.02.
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