4-Substituted anilino imidazo[1,2-a] and triazolo[4,3-a]quinoxalines. Synthesis and evaluation of in vitro biological activity

Article abstract of DOI:10.1016/j.ejmech.2006.05.015

Fifteen imidazo[1,2-a] and [1,2,4]triazolo[4,3-a]quinoxalines were prepared. These compounds bear at position 4 various substituents related to the moieties present in classical and non-classical antifolic agents. And we evaluated in vitro antimicrobial,

Full text of DOI:10.1016/j.ejmech.2006.05.015

European Journal of Medicinal Chemistry 41 (2006) 1102–1107
http://france.elsevier.com/direct/ejmech
Laboratory note
4-Substituted anilino imidazo[1,2-a] and triazolo[4,3-a]quinoxalines.
Synthesis and evaluation of in vitro biological activity
a
a
a
a,
b,
*
*
Paola Corona , Gabriella Vitale , Mario Loriga , Giuseppe Paglietti , Paolo La Colla ,
Gabriella Collub, Giuseppina Sannab, Roberta Loddob
a Dipartimento Farmaco Chimico Tossicologico, University of Sassari, Via Muroni 23/a, 07100 Sassari, Italy
b Dipartimento di Scienze e Tecnologie Biomediche, Sezione di Microbiologia e Virologia Generale e Biotecnologie Microbiche,
University of Cagliari, Cittadella Universitaria, Strada Statale, 554-09042 Cagliari, Italy
Received in revised form 20 May 2006; accepted 29 May 2006
Available online 07 July 2006
Abstract
Fifteen imidazo[1,2-a] and [1,2,4]triazolo[4,3-a]quinoxalines were prepared. These compounds bear at position 4 various substituents related
to the moieties present in classical and non-classical antifolic agents. And we evaluated in vitro antimicrobial, antiviral and antiproliferative
activities. In particular, title compounds were evaluated in vitro against representative strains of Gram-positive and Gram-negative bacteria
(S. aureus, Salmonella spp.), mycobacteria (M. fortuitum, M. smegmatis ATCC 19420 and M. tuberculosis ATCC 27294), yeast and moulds
(C. albicans ATCC 10231 and A. fumigatus). Furthermore, their antiretroviral activity against HIV-1 was determined in MT-4 cells together with
cytotoxicity. In these assays title compounds were tested for their capability to prevent MT-4 cell growth. Among the examined series, the
compounds 5, 7 and 10 showed cytotoxicity against mock-infected MT-4 cells.
© 2006 Elsevier SAS. All rights reserved.
Keywords: Imidazo[1,2-a]quinoxalines; Triazolo[4,3-a]quinoxalines; Biological activity
1. Introduction
Our research group has been for long involved in a wide
program aimed to discover anticancer activity in quinoxaline
antifolate analogues on the basis that quinoxaline ring may
act as bioisoster of both pteridine and quinazoline rings present
in the most representative drugs as MTX, trimetrexate and
tomudex. The results on the anticancer activity recorded at
NCI (Bethesda) of our compounds showed that most of them
were endowed with both anticancer and antifolic activity in the
range of 10–0.1 μM concentration [2–17]. In this context we
have also designed heterocyclic-fused quinoxalines of Fig. 3
Structural analogy with the substrate has been successfully
employed for developing an antimetabolite strategy in the case
of antifolate drugs. Methotrexate (MTX), the closest drug to
folic acid, inhibits dihydrofolate reductase (DHFR) and
remains an unvaluable antifolic agent even though accompa-
nied with drug resistance (Fig. 1).
Research efforts have concentrated on the discovery of safer
or more potent compounds and a survey of these results has
recently appeared [1]. In the past decade only two new agents
have been introduced endowed with strong thymidilate
synthase (TS) inhibitory activity (Tomudex and pemetrexed)
(Fig. 2).
* Corresponding authors. Tel.: +39 079 22 8704; fax: +39 079 22 8720
(G.P.), tel.: +39 070 675 4147; fax: +39 070 675 4210 (P.L.C.).
E-mail addresses: paglietti@uniss.it (G. Paglietti), placolla@unica.it
(P. La Colla).
Fig. 1.
0223-5234/$ - see front matter © 2006 Elsevier SAS. All rights reserved.
doi:10.1016/j.ejmech.2006.05.015

P. Corona et al. / European Journal of Medicinal Chemistry 41 (2006) 1102–1107
1103
Fig. 2.
Fig. 3.
which bear the usual side chains of classical and non-classical
antifolate drugs.
ment in the quinoxaline structure might exhibit this type of
activity.
This modification originates from the observations reported
in the literature that this type of annelation was successful in
causing selectivity and stronger affinity of a pharmacophore
element towards different receptor binding sites. As examples
we can cite many current benzodiazepine drugs (alprazolam,
triazolam, midazolam) [18]; pyrrolo[1,2-a]quinoxalines as
5-HT3 receptor agonists [19]; non-peptide glucagons
antagonists [20]; [1,2,4]triazolo[4,3-a]quinoxalines [21] and
[1,2,4]triazolo[1,5-a]quinoxalylamines [22] and imidazo[1,2-a]
quinoxalylamines [23] as adenosin antagonists as well as 1,2-
dihydro-imidazo[1,2-a]quinoxaline-N-oxides as anticancer
agents [24].
2. Chemistry
The preparation of the compounds was accomplished
according to the reactions described in Scheme 1. The starting
material
chloroimidazo[1,2-a]
and
chlorotriazolo[4,3-
a]quinoxalines (1a–c) were obtained according to previously
reported procedure [23,29]. Nucleophilic attack by the corre-
sponding anilines 17–20, in refluxing ethanol or 1-propanol
gave the anilinoimidazo[1,2-a] and anilinotriazolo[4,3-
a]quinoxalines 2–10 and the esters 11, 13, 15 in good yields.
The desired acids 12, 14, 16 were obtained on alkaline hydro-
lysis in hydro-alcoholic medium of the esters 11, 13 and 15.
Thus, annelating the 1,2-bond of the pyrazine ring with an
additional “electron-rich” ring might extend on one hand the
planarity of the heteroring and on the other hand modulate
either the lipophilicity or hydrogen bond accepting property.
In other words two requirements for a better alleged affinity
for the folate receptor.
3. Experimental protocols
Melting points are uncorrected and were determined by a
Kofler hot stage or Digital Electrothermal apparatus. UV spec-
tra are qualitative and were recorded in nm for solutions in
ethanol with Perkin–Elmer Lambda 5 spectrophotometer. IR
spectra (Nujol mulls) were recorded with Perkin–Elmer 781
instrument. 1H NMR spectra were recorded with a Varian
XL-200 (200 MHz) instrument, using TMS as internal stan-
dard. Elemental analyses were performed by the Laboratorio
di Microanalisi, Dipartimento di Chimica, University of
Sassari, Italy. The analytical results for C, H, N were within
0.4% of the theoretical values.
With this in mind we previously described a series of pyr-
roloquinoxalines (a) of Fig. 3 and we found that some of these
compounds were endowed with in vitro antiproliferative activ-
ities as low as 3.4 μM against a panel of cell lines derived from
hematological and solid tumors [25]. In this note we have
taken into account the preparation of compounds of b and c
type 2–10 and 11–16 (Fig. 4) where pyrrole[1,2-a]quinoxaline
ring has been bioisosterically replaced by both imidazo[1,2-a]-
and triazolo[4,3-a]quinoxaline. In addition, they display a sub-
stituent in the azole ring that, in our opinion, was supposed to
modulate both the lipophilicity and its possible interaction with
the target.
3.1. Chemistry
3.1.1. Intermediates
Furthermore, the title molecules were also considered for an
investigation of whatsoever antimicrobial and antiviral activity
since both imidazole and triazole rings are good representatives
of different classes of antiinfectives [26–28] and their embodi-
4-Chloroimidazo[1,2-a]quinoxaline (1a), 4-chlorotriazolo
[4,3-a]quinoxaline (1b) and 1-methyl-4-chlorotriazolo[4,3-a]
quinoxaline (1c) necessary for this work were known and

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P. Corona et al. / European Journal of Medicinal Chemistry 41 (2006) 1102–1107
yields, melting points, analytical and spectroscopic data were
reported.
3.1.3. Diethyl N-[4-(imidazo[1,2-a]quinoxalin-4-yl)amino]
benzoyl-L-glutamate (11), diethyl N-[4-(triazolo[4,3-a]
quinoxalin-4-yl)amino]benzoyl-L-glutamate (13) and diethyl N-
[4-(1-methyl-triazolo[4,3-a]quinoxalin-4-yl)amino]benzoyl-L-
glutamate (15)
A solution of equimolar amounts (1.5 mmol) of 1a–c and
the p-aminobenzoyl-L-glutamate (20) in ethanol (90 ml) for 11
and 13 or in 1-propanol (25 ml) for 15 was refluxed for 9 h
(11, 15) and 4 h (13). After cooling a cream colored solid pre-
cipitate (11 and 15) was filtered off and washed with ethanol or
1-propanol. In the case of compound 13 the solution was eva-
porated in vacuo to give a solid residue. Purification methods,
yields, melting points, analytical and spectroscopic data are
reported in Table 1.
3.1.4. General procedure for the preparation of the acids 12,
14, 16
A mixture of ester (11, 13, 15) (0.5 mmol) in ethanol
(15 ml) and 1 M NaOH aqueous solution (6 ml) was refluxed
for 1 h for 12 and 16, or 4 h in the case of compound 14. After
cooling the reaction mixture was quenched with an equimolar
amount of 1 M HCl aqueous solution. The solids precipitated
were filtered off and washed with water.
Compounds 12, 14 and 16 were purified by recrystallization
as reported below. Yields, reaction conditions, melting points,
analytical and spectroscopic data are reported in Table 1.
4. Microbiology
The new compounds were evaluated in vitro against
representative strains of Gram-positive and Gram-negative
bacteria (S. aureus, Salmonella spp.), various mycobacterial
strains (M. fortuitum, M. smegmatis ATCC 19420 and
M. tuberculosis ATCC 27294), and yeast and mould strain
(C. albicans ATCC 10231 and A. fumigatus). Title compounds
were also evaluated for anti-HIV-1 activity in MT-4 cells.
4.1. Microbiological assays
Fig. 4.
4.1.1. Compounds
Test compounds were solubilized in DMSO at 100 mM and
then diluted into culture medium.
were prepared according to the data of literature: 1a [23], 1b, c
[29].
4.2. Cells and viruses
3.1.2. General procedure for the preparation of 4-anilino
imidazo[1,2-a]quinoxalines (2–4) and of 4-anilino triazolo
[4,3-a]quinoxalines (5–10)
A mixture of equimolar amounts (1.2 mmol) of 1a–c and
the corresponding substituted anilines 17–19 of Scheme 1 in
ethanol (for 3–7) or 1-propanol (for 2, 8–10) was refluxed for
4–5 h (3–7) and for 2 h (2, 8–10). After cooling the solvent
was removed under reduced pressure and the colored residues
2–10 were further purified as described in Table 1 where
Cell lines were purchased from American Type Culture Col-
lection (ATCC). The absence of mycoplasma contamination
was checked periodically by the Hoechst staining method.
Cell lines supporting the multiplication of RNA viruses were
the following: CD4+ human T-cells containing an integrated
HTLV-1 genome (MT-4); Madin Darby bovine kidney
(MDBK); baby hamster kidney (BHK-21); monkey kidney
(Vero 76).

P. Corona et al. / European Journal of Medicinal Chemistry 41 (2006) 1102–1107
1105
Scheme 1. Reaction conditions: i, EtOH reflux Δ/5.5h; ii, propOH, reflux 2h; iii, propOH, reflux 9h; iv; EtOH, NaOH 1M, reflux 2/13h
4.3. Cytotoxicity and antiproliferative assays
ried out in Tryptose agar for S. aureus, Salmonella spp. and
Sabouraud dextrose broth for C. albicans and A. fumigatus,
with an inoculum of 103 bacteria per ml and 5 × 103 yeast
per ml. A. fumigatus inocula were obtained from cultures
grown at 37 °C for 1 day and then diluting to 0.05 OD50 per
ml. Minimum inhibitory concentrations (MIC) were deter-
mined after incubations at 37 °C for 18 h in the presence of
serial dilutions of test compounds.
Exponentially growing cells were resuspended in
growth medium containing serial dilutions of the drugs. Cell
viability was determined after 96 h at 37 °C by the 3-
(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide
(MTT) method [30].
4.4. Antiviral assays
4.6. Anti-mycobacterial assays
Activity of compounds against HIV-1 was based on inhibi-
tion of virus-induced cytopathogenicity in MT-4 cells acutely
infected at a multiplicity of infection of 0.01.
M. tuberculosis 27294 and M. smegmatis 19420 were
ATCC strains, M. fortuitum was clinical isolate. MICs were
assessed in microtiter plates by adding 20 μl aliquots of a cul-
ture suspension to 80 μl of Middlebrook 7H9 medium contain-
ing serial dilutions of test compounds. At the end of incuba-
tion, the number of viable mycobacteria was determined by the
MTT method.
Activity against YFV, DENV-2 and WNV was based on
inhibition of virus-induced cytopathogenicity in acutely infected
BHK-21 cells. Activity against BVDV was based on inhibition
of virus-induced cytopathogenicity in acutely infected MDBK
cells. Cells were seeded overnight at a rate of 5 × 104 per well
into 96-well plates in growth medium at 37 °C, in a humidified
CO2 (5%) atmosphere. Cell monolayers were infected with 50 μl
of a proper virus dilution to give an m.o.i. = 0.01. Then, serial
dilutions of test compounds in Dulbecco’s modified Eagle’s
medium, supplemented with 2% inactivated fetal calf serum,
were added. After a 3 days incubation at 37 °C, cell viability
was determined by the MTT method.
5. Results and discussion
All the compounds were evaluated in biological assays (the
most significant results are shown in Table 2) in order to iden-
tify their potential antimicrobial and antiviral activities. How-
ever, none of the extracts showed activity against representa-
tives strains of Gram-positive and Gram-negative bacteria (S.
aureus, Salmonella spp.), nor against mycobacteria
(M. fortuitum, M. smegmatis and M. tuberculosis). Test
extracts were also inactive against representative strains of
4.5. Antibacterial and antimycotic assays
S. aureus, Salmonella spp. and A. fumigatus were clinical
isolates, C. albicans 10231 was ATCC strain. Assays were car-

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P. Corona et al. / European Journal of Medicinal Chemistry 41 (2006) 1102–1107
Table 1
Physical and analytical data of compounds of Fig. 4
1H NMR, δH (J in Hz)
Com-
M.p. (°C) Yield
Analysis for
IR
UV
pounds
(*)
(%)
(Nujol)
(EtOH)
λmax (nm)
Solvent: [A] = CDCl3 [B] = CDCl3/DMSO-d6 (3:1) [C] = CDCl3/DMSO-d6 (1:1)
[D] = DMSO-d6
nmax
(cm−1
3524,
1622
)
2
3
4
74–78a
44
C19H18N4O3
C18H16N4O2
C17H14N4O
351, 335, [A] 8.18 (1H, br s, NH), 8.02 (1H, s, H-1), 7.81 (1H, dd, J9,8 = 7.8 Hz and J9,7 = 1.6 Hz,
297, 225, H-9), 7.74 (1H, dd, J6,7 = 7.8 Hz and J6,8 = 1.6 Hz, H-6), 7.63 (1H, s, H-2), 7.56–7.40
201
332, 293, [C] 8.54(1H, br s, NH), 8.08 (1H, dd, J9,8 = 7.8 Hz and J9,7 = 1.6 Hz, H-9 and 1H, s, H-1),
284, 261, 7.78 (1H, dd, J6,7 = 7.8 Hz and J6,8 = 1.6 Hz, H-6), 7.71 (1H, s, H-2), 7.50 (2H, s, H-2′,
227, 211 6′), 7.50–7.39 (2H, m, H-7,8), 6.21 (1H, s, H-4′), 3.82 (6H, s, 3′, 5′, –OCH3)
340, 295, [A] 10.58 (1H, br s, NH), 8.02 (1H, s, H-1), 7.93 (2H, d, J = 8.2 Hz, H-2′, 6′), 7.85 (1H,
286, 264, dd, J6,7 = 8.2 Hz and J6,8 = 1.6 Hz, H-6), 7.74 (1H, dd, J9,8 = 8.2 Hz and J9,7 = 1.6 Hz, H-
227, 202 9), 7.63 (1H, s, H-2), 7.56–7.30 (2H, m, H-7, 8), 6.97 (2H, d, J = 8.2 Hz, H-3′, 5′), 3.81
(3H, s, 4′-OCH3)
(2H, m, H-7,8), 7.39 (2H, s, H-2′, 6′), 3.95 (6H, s, 3′,5′-OCH3), 3.86 (3H, s, 4′-OCH3)
114–115a 69
3356,
1610
145.5–
89.74
3308,
1622
147.5a
5
225–226a 91
229–230a 81
216–219b 79
242–244a 67
233–234a 65
214–216a 60
179–181a 55
C18H17N5O3
C17H15N5O2
C16H13N5O
C19H19N5O3
C18H17N5O2
C17H15N5O
C26H27N5O5
3574,
1584
391, 324, [B] 10.58 (1H, br s, NH), 9.55 (1H, s, H-1), 7.96 (1H, d, J6,7 = 7.8 Hz, H-6), 9.74 (1H, d,
296, 196 J9,8 = 7.8 Hz, H-9), 7.55 (2H, s, H-2′, 6′), 7.48–7.35 (2H, m, H-7,8), 3.94 (6H, s, 3′,
5′-OCH3), 3.83 (3H, s, 4′-OCH3)
6
3403,
1630
319, 293, [A] 9.21 (1H, s, H-1), 8.19 (1H, br s, NH), 7.89 (1H, dd, J6,7 = 6.8 Hz, and J6,8 = 1.4 Hz,
197
H-6), 7.79 (1H, dd, J9,8 = 6.8 Hz and J9,7 = 1.4 Hz, H-9), 7.61–7.57 (2H, m, H-7,8), 7.27
(2H, d, J2′,6′ = 2.2 Hz, H-2′, 6′), 6.29 (1H, t, H-4′), 3.87 (6H, s, OCH3)
7
3355,
1659
338, 314, [B] 10.58 (1H, br s, NH), 10.05 (1H, s, H-1), 8.24 (1H, dd, J6,7 = 7.8 Hz and J6,8 = 1.6 Hz,
224, 202 H-6), 7.92 (2H, d, J2′,6′ = 9 Hz, H-2′, 6′), 7.78 (1H, dd, J9,8 = 7.8 Hz and J9,7 = 1.6 Hz, H-
9), 7.60-7.40 (2H, m, H-7, 8), 6.98 (2H, d, J3′,5′ = 9 Hz, H-3′, 5′), 3.83 (3H, s, 4′-OCH3)
340, 311, [A] 8.72 (1H, s, NH), 8.01 (1H, d, J6,7 = 8.2 Hz, H-6), 7.82 (1H, d, J9,8 = 8.2 Hz, H-9),
298, 212 7.57 (1H, t, H-7), 7.43 (1H, t, H-8), 7.29 (2H, s, H-2′, 6′), 3.88 (6H, s, 3′, 5′-OCH3), 3.84
(3H, s, 4′-OCH3), 3.14 (3H, s, CH3)
334, 310, [A] 8.30 (1H, s, NH), 7.99 (1H, d, J6,8 = 8.4 Hz, H-6), 7.85 (1H, d, J6,7 = 8.4 Hz, H-9),
297, 213 7.52 (1H, t, H-7), 7.30 (1H, t, H-8), 7.24 (2H, d, J2′,6′ = 1.6 Hz, H-2′, 6′), 6.25 (1H, s, H-
4′), 3.84 (6H, s, 3′, 5′-OCH3), 3.13 (3H, s, CH3)
8
3464,
1611
9
3410,
1614
10
11
3190,
1611
338, 310, [A] 8.10 (1H, pr s, NH), 8.05 (1H, d, J6,9 = 7.9 Hz, H-6), 7.88 (2H, d, J3′,5′ = 8.8 Hz, H-3′,
218
5′) 7.85 (1H, d, J = 7.8 Hz, H-9, partially obscured) 7.51 (1H, t, H-7), 7.38 (1H, t, H-8),
6.97 (2H, d, J2′,6′ = 8.8 Hz, H-2′,6′), 3.84 (3H, s, 4′-OCH3), 3.13 (3H, s, CH3)
3321,
1725,
1631
350, 335, [B] 10.50 (1H, br s, NH), 8.47 (1H, s, H-1), 8.37 (1H, d, CONH), 8.27 (2H, d,
296, 287, J3′,5′ = 7.8 Hz, H-3′, 5′), 8.04 (1H, d, J5,6 = 7.8 Hz, H-5), 7.95 (2H, d, J2′,6′ = 8.6 Hz, H-2′,
220, 204 6′), 7.85 (1H, d, J8,7 = 7.2 Hz, H-8), 7.76 (1H, s, H-2), 7.60–7.41 (2H, m, H-7,6),
4.70–4.56 (1H, m, CH), 4.20 (2H, q, COOCH2CH3), 4.11 (2H, q, COOCH2CH3),
2.55–2.00 (4H, m, CH2CH3), 1.30 (3H, t, COOCH2CH3), 1.24 (3H, t, COOCH2CH3)
350, 335, [B] 10.50 (1H, br s, NH), 8.63 (1H, s, H-1), 8.46 (1H, s, CONH), 8.33 (2H, d,
306, 294, J3′,5′ = 8.8 Hz, H-3′, 5′), 8.15 (1H, dd, J6,7 = 6.8 Hz and J6,8 = 5 Hz, H-6), 7.94 (2H, d,
286, 220, J2′,6′ = 8.8 Hz, H-2′,6′), 7.81 (1H, dd, J9,8 = 7.6 Hz and J9,7 = 5 Hz, H-9), 7.72 (1H, s, H-
12
13
14
15
16
> 300c
42
94
74
C22H19N5O5
3518,
3400(sh)
3306,
1702,
1609
3296,
1713,
202
2), 7.53–7.40 (2H, m, H-7,8), 6.00 (2H, br s, COOH), 4.55–4.40 (1H, m, CH), 2.50–1.98
(4H, m, CH2CH2)
208–210
> 300d
C
25H26N6O5
323, 295, [B] 10.50 (1H, br s, NH), 9.88 (1H, s, H-1), 8.39 (1H, d, CONH), 10.27 (2H, d,
283, 250, J3′,5′ = 8.8 Hz, H-3′, 5′), 8.15 (1H, d, J6,7 = 8 Hz, H-6,7), 7.95 (2H, d, J2′,6′ = 8.Hz, H-
1632, 160 202
2′,6′), 7.8 (1H, d, J9,8 = 8. Hz, H-9), 7.58-7.40 (2H, m, H-7,8), 6.00 (2H, br s, COOH),
4.70–4.50 (1H, m, CH), 4.20 (2H, q, CH2CH3), 4.11 (2H, q, CH2CH3), 2.0-2.00 (4H, m,
CH2CH2), 1.30 (3H, t, CH2CH3), 1.25 (3H, t, CH2CH3)
C21H18N6O5
C26H28N6O5
C22H20N6O5
3500 (sh), 338, 311, [A] 10.55 (1H, br s, NH), 10.11 (1H, s, H-1), 8.55 (1H, d, CONH), 8.34–8.30 (2H, d,
3250,
1704,
1643,
1606
3342,
3309,
1743,
1631,
1605
3315,
1710,
1635,
1610
263, 218, J3′,5′ = 8.2 Hz, H-3′, 5′ and 1H, H-6), 7.95 (2H, d, J2′,6′ = 8.8 Hz, H-2′, 6′), 7.81 (1H, dd,
203
J9,8 = 7.8 Hz and J9,7 = 1.8 Hz, H-9), 7.65–7.55 (2H, m, H-7, 8), 6.00 (2H, br s, COOH),
4.50-4.40 (1H, m, CH), 2.55-1.90 (4H, m, CH2CH2)
226–228a 54
294–296d 77
335, 321, [D] 10.41 (1, s, NH), 6.65 (1H, d, J = 7.2 Hz, CONH), 8.33 (2H, d, J3′,5′ = 8.6 Hz, H-3′,
295, 281, 5′), 8.21 (1H, d, J6,7 = 8.2 Hz, H-6), 7.92 (2H, d, J2′,6′ = 8.8 Hz, H-2′, 6′), 9.80 (1H, dd,
249, 204 J9,8 = 7.8 Hz and J9,7 = 1.6 Hz, H-9), 7.62–7.44 (2H, m, H-7, 8), 4.50–4.40 (1H, m, CH),
4.13 (2H, q, COOCH2CH3), 4.07 (2H, q, COOCH2CH3), 3.09 (3H, s, CH3), 2.48 (2H, t,
CH2CO), 2.20-1.9 (2H, m, COCHCH2), 1.21 (3H, t, CH2CH3), 1.18 (3H, t, CH2CH3)
336, 310, [D] 10.39 (1H, s, NH), 8.58 (1H, d, CONH), 8.32 (2H, d, J3′,5′ = 8.4 Hz, H-3′, 5′), 8.20
297, 220, (1H, d, J6,7 = 8.4 Hz, H-6), 7.93 (2H, d, J2′,6′ = 8.4 Hz, H-2′,6′), 7.81 (1H, d, J9,8 = 8.4 Hz,
202
H-9), 7.70–7.40 (2H, m, H-7,8), 6.07 (2H, br s, COOH), 4.52–4.35 (1H, m, CH), 3.09
(3H, s, 1-CH3), 2.60-1.90 (4H, m, CH2CH2)
(*) Purification procedure.
a
Crystallization from EtOH.
Crystallization from EtOH/H2O.
Crystallization from CH3COOH.
Crystallization from DMSO; sh, shoulder.
b
c
d

P. Corona et al. / European Journal of Medicinal Chemistry 41 (2006) 1102–1107
1107
Table 2
[10] G. Vitale, P. Corona, M. Loriga, G. Paglietti, Farmaco 53 (1998) 139–
149.
Cytotoxicity of compounds 2–16
CC50a MT-4
= 100
> 100
> 100
40
68
> 100
93
Compounds
CC50a MT-4
51
[11] G. Vitale, P. Corona, M. Loriga, G. Paglietti, Farmaco 53 (1998) 150–
159.
[12] P. Corona, G. Vitale, M. Loriga, G. Paglietti, M.P. Costi, Farmaco 53
(1998) 480–493.
[13] G. Vitale, P. Corona, M. Loriga, G. Paglietti, Farmaco 53 (1998) 594–
601.
[14] P. Corona, G. Vitale, M. Loriga, G. Paglietti, Farmaco 55 (2000) 77–86.
[15] S. Piras, M. Loriga, G. Paglietti, Farmaco 57 (2002) 1–8.
[16] M. Loriga, S. Piras, G. Paglietti, M.P. Costi, A. Venturelli, Farmaco 58
(2003) 51–61.
[17] S. Piras, M. Loriga, G. Paglietti, Farmaco 59 (2004) 189–194.
[18] P.V. Nickell, H.E. Ward Jr., R.G. Booth, in: M.E. Wolff (Ed.), Anti
Anxiety Agents in Burger’s Medicinal Chemistry and Drug Chemistry,
Fifth ed., Vol. 5, J. Wiley & Sons, New York, 1997, p. 153 (and refer-
ences cited therein).
[19] G. Campiani, A. Cappelli, V. Nacci, M. Anzini, S. Vomero, M. Hamon,
A. Cagnotto, C. Fracasso, C. Uboldi, S. Caccia, S. Consolo, T. Mennini,
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Compounds
2
3
4
5
7
8
9
a
10
11
12
13
14
15
16
> 100
> 100
> 100
> 100
> 100
> 100
Compound dose (μM) required to reduce the viability of mock-infected
MT-4 cells by 50%, as determined by the MTT method.
yeasts and moulds (C. albicans ATCC 10231 and
A. fumigatus).
The compounds were also tested for antiviral activity
against HIV, BVDV and YFV (which are used as surrogate
models for HCV), other RNA viruses, such as Coxsackie B
and Reo, and DNA viruses (HSV-1, HSV-2, Vaccinia and
HBV). None of the compounds showed any activities against
all viruses we tested. However, the compounds 5, 7 and 10
showed cytotoxicity against the T-lymphocyte cell line used
for the anti-HIV-1 activity.
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Acknowledgements
The authors gratefully acknowledge MIUR-Rome for sup-
port COFIN 2004 project on antitumor compounds.
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