Synthesis and anti-measles virus activity of new isoquinolin-4-one derivatives

Article abstract of DOI:10.1016/j.farmac.2003.07.003

Despite intense efforts to increase vaccine coverage, measles virus (MV) still causes significant morbidity and mortality in the world sometimes as a results of severe, chronic and lethal diseases. In an effort to develop therapies to supplement immunization strategies a number of 1-oxo-2-{[(1E)- phenylmethylene]amino}-1,2-dihydroisoquinoline-4-carboxylic acid derivatives were synthesized and evaluated for anti-measles activity. The substituents on the aromatic ring were chosen in order to evaluate the influence of electron-withdrawing or electron-donating effects on the electronic density of the aromatic moiety. We also evaluated the introduction of a vinyl chain between the exocyclic nitrogen and phenyl moiety. The biological results allow to outline some preliminary considerations on structure-activity relationship.

Full text of DOI:10.1016/j.farmac.2003.07.003

Il Farmaco 58 (2003) 1217ꢀ1225
/
www.elsevier.com/locate/farmac
Synthesis and anti-measles virus activity of new isoquinolin-4-one
derivatives
a,
N.A. Santagati *, E. Bousquet , A. Garozzo , O. Prezzavento , A. Spadaro ,
a
b
a
a
a
G. Ronsisvalle
a
Dipartimento di Scienze Farmaceutiche, Facolta di Farmacia, Universit a` degli Studi di Catania, Viale Andrea Doria, 6, 95125 Catania, Italy
b
Dipartimento di Scienze Microbiologiche e Ginecologiche, Universit a` degli Studi di Catania, Via Androne 81, 95124 Catania, Italy
Received 28 May 2003; accepted 18 July 2003
Abstract
Despite intense efforts to increase vaccine coverage, measles virus (MV) still causes significant morbidity and mortality in the
world sometimes as a results of severe, chronic and lethal diseases. In an effort to develop therapies to supplement immunization
strategies a number of 1-oxo-2-{[(1E)-phenylmethylene]amino}-1,2-dihydroisoquinoline-4-carboxylic acid derivatives were synthe-
sized and evaluated for anti-measles activity. The substituents on the aromatic ring were chosen in order to evaluate the influence of
electron-withdrawing or electron-donating effects on the electronic density of the aromatic moiety. We also evaluated the
introduction of a vinyl chain between the exocyclic nitrogen and phenyl moiety. The biological results allow to outline some
preliminary considerations on structureꢀ
/
activity relationship.
2003 Editions scientifiques et m e´ dicales Elsevier SAS. All rights reserved.
´
#
Keywords: Isoquinolin-4-one derivatives; Synthesis; Structureꢀ/activity relationship; Anti-viral activity; Measles virus
1
. Introduction
Despite the availability of efficacious vaccines and
eradication efforts measles virus (MV) is one of leading
MV demonstrates substantial heterogeneity [4]. In the
last decade, genotyping studies have indicated that the
RNA sequences of the MV strains currently circulating
have changed considerably from those isolated pre-
viously. This suggests that MV may contribute con-
siderably to worldwide morbidity and mortality as it
evolves consequently to the elimination efforts. There-
fore, to treat unexpected outbreak infections rapidly and
efficiently may be useful to supplement global immuni-
zation with non-toxic treatments.
No chemotherapeutic agents are currently approved
for use for the prophylaxis or treatment of measles,
although ribavirin has reportedly been efficacious when
administered intravenously and orally for treatment of
causes of infectious disease-induced morbidity and
mortality in childhood in the world. Currently 30ꢀ40
/
million measles infections occurs worldwide each year
lead to 1 million deaths due to MV-related infections [1].
In addition to causing an acute respiratory infection,
measles is also correlated with an important, but
transient suppression of cell-mediated immunity that
can lead to secondary infections, and complications such
as pneumonia and diarrhoea.
There are highly effective vaccines available, although
their safety has been occasionally questioned because of
tenuous and questionable link to Crohn disease and to
autism [2,3].
MV infections [5ꢀ7] alone or in combination with
/
immune serum globulin in patients [8,9]. Regardless of
their clinical efficacies, both ribavirin and immune
serum globulin are costly [10,11] and require hospitali-
zation for administration [12], limiting the use of either
of these agents for the treatment of measles, particularly
in developing countries where this disease is most
preponderant. To date no other clinical trials have
been done that support these findings of efficacy; on
Of interest for the eradication of MV outbreaks is that
virus isolates are not of single geno- or serotype, hence
* Corresponding author.
E-mail address: santagat@unict.it (N.A. Santagati).
´
0
014-827X/03/$ - see front matter # 2003 Editions scientifiques et m e´ dicales Elsevier SAS. All rights reserved.
doi:10.1016/j.farmac.2003.07.003

1218
N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ1225
/
the contrary, a number of studies have also been done
showing that ribavirin has no obvious clinical efficacy in
MV infections when given as small-particle aerosol or
intravenously [13]. The continued prevalence of measles
and the paucity of available agents for the prevention or
treatment of MV infections make the elucidation and
development of new chemotherapeutic and/or biologic
agents effective against this virus highly desirable.
Several compounds with antiviral activity versus
myxovirus and paramyxovirus such as UK 2054 (famo-
Canada). Elemental analyses (C, H, N) were determined
on an elemental analyser Carlo Erba Model 1106 (Carlo
Erba, Milano, Italy), and were within 9
/
0.4% of the
theoretical values.
2.2. Synthesis of 2-amino-1-oxo-1,2-dihydroisoquinoline-
4-carboxylic acid (2)
A solution of 1 (2.0 g, 10 mmol) and hydrazine
monohydrate (15 ml, 309 mmol) in 40 ml of absolute
ethanol was refluxed for 1 h. The solution was allowed
to cool to room temperature (r.t.) and subsequently
diluted hydrochloric acid was added until to pH 4. The
precipitate obtained was collected by filtration and
washed with water until to neutral pH. Finally the
tine),
the corresponding p-methoxy analogous UK 2371
memotine), and DIQA, 2-(3,4-dihydroisoquinolin-1-
1-[(p-clorofenoxymethyl]-3,4-dihydroquinoline,
(
yl)acetamide, have an isoquinoline nucleus in their
structure [14,15] (Fig. 1). As part of our ongoing interest
in the area of isoquinoline derivatives [16], in this paper,
white solid was crystallised from ethyl alcohol to give
1
1.32 g of desired acid (65%). H NMR (DMSO-d ): d,
we disclose our synthetic efforts and structureꢀ
/
activity
relationship (SAR) studies that led to the identification
6
12.92 (s broad, 1H, COOH), 8.67 (d, 1H, ArH), 8.15 (d,
1H, ArH), 8.14 (s, 1H, ArH), 7.72 (t, 1H, ArH), 7.46 (t,
of a novel group of analogues with isoquinoline scaffold
(
A) having antiviral activity against MV (Fig. 1).
1H, ArH), 6.43 (s broad, 2H, Ã
/NH2).
2.3. General procedure for synthesis of N-arylenamine
2
. Experimental procedures
derivatives (3ꢀ16)
/
2
.1. Chemistry
The appropriate aldehydes (3 mmol), was added to a
solution of 2 (2 mmol) in 25 ml of acetic acid, and was
heated for 30 min under reflux. The mixture obtained
was cooled to r.t. and the precipitate was collected by
filtration. Afterward the solid was washed with water
and was crystallised by opportune solvents. Yields,
melting points and crystallization solvents are reported
in Table 1.
Reagents used for synthesis were purchased from
Sigma Aldrich (Milano, Italy) unless otherwise specified.
The course of the reaction was monitored by thin-layer
chromatography (TLC) on precoated silica gel 60 F254
aluminium sheets (Merck, Darmstadt, Germany), visua-
lisation was provided under UV light. Melting points
were obtained in open capillary tubes with a B u¨ chi
apparatus (B u¨ chi Italia, Assago, Italy) and are uncor-
rected. Infrared spectra (IR) were recorder in KBr disks
2.3.1. 1-oxo-2-{[(1E)-phenylmethylene]amino}-1,2-
dihydroisoquinoline-4-carboxylic acid (3)
1
using a 1600 FT-IR Perkinꢀ
/
Elmer (Perkinꢀ
/
Elmer Italia,
H NMR (DMSO-d
N), 8.67 (d, 1H, ArH), 8.41 (s, 1H,
ArH), 8.31 (d, 1H, ArH), 7.93ꢀ7.78 (m, 3H, ArH),
7.68ꢀ7.42 (m, 4H, ArH).
6
): d 13.02 (s broad, 1H, COOH),
Monza, Italy) spectrophotometer and are consistent
with the assigned structures. Nuclear magnetic reso-
nance (NMR) spectra were recorded with a Varian
Inova 200 spectrometer (Varian, Leini, Italy). NOE
experiments were carried out using the standard CY-
CLENOE pulse sequence on the Varian spectrometer.
Log D and solubility were calculated using ACD/Labs
software (version 4.5, 2000, ACD, Toronto, ON,
9.12 (s, 1H, CHÄ
/
/
/
2.3.2. 2-{[(1E)-(4-chlorophenyl)methylene]amino}-1-
oxo-1,2-dihydroisoquinoline-4-carboxylic acid (4)
1
H NMR (DMSO-d ): d 13.02 (s broad, 1H, COOH),
6
9.44 (s, 1H, CHÄ/N), 8.89 (d, 1H, ArH), 8.43 (s, 1H,
Fig. 1. UK 2054 (Famotine), 1-[(p-clorofenoxymethyl]-3,4-dihydroquinoline, the corresponding p-methoxy analogous UK 2371 (memotine), DIQA,
-(3,4-dihydroisoquinolin-1-yl)acetamide and (A) isoquinoline derivatives synthesized in this study.
2

N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ
/1225
1219
Table 1
Structures, yields and melting points of the prepared quinazolinones derivatives
Compound
R
Yield (%)
Melting point (8C)
Formula
a
3
Ã
/
C
C
C
C
C
C
C
C
C
6
6
6
6
6
6
6
6
6
H
H
H
H
H
H
H
H
H
5
4
4
4
4
4
4
4
4
73
78
83
85
90
58
75
64
79
87
81
65
86
68
262ꢀ
293ꢀ
295ꢀ
295ꢀ
298ꢀ
/
4
4
7
6
9
C
C
C
C
C
C
C
C
C
C
C
C
C
C
17
H
17
H
17
H
17
H
17
H
17
H
17
H
17
H
17
H
19
H
17
H
17
H
17
H
17
H
12
N
11
N
12
N
11
N
12
N
11
N
12
N
12
N
12
N
13
N
12
N
12
N
12
N
12
N
2
2
2
2
2
3
2
2
2
2
2
2
2
2
O
3
O
3
O
3
O
3
O
3
O
5
O
3
O
4
O
3
O
3
O
3
O
3
O
3
O
3
a
4
Ã
/
-4-Cl
-2-Cl
-4-Br
-2-Br
-4-NO
/
Cl
Br
a
5
Ã
/
/
a
6
Ã
/
/
a
7
Ã
/
/
b
8
Ã
/
2
ꢀ300
/
b
9
Ã
/
-2-COOH
-4-OH
287ꢀ
280ꢀ
253ꢀ
264ꢀ
261ꢀ
256ꢀ
272ꢀ
268ꢀ
/
9
1
5
6
2
8
4
9
b
1
1
0
1
Ã
/
/
b
a
a
a
Ã
/
-4-OCH
CHÃ
CH
C(CH )ꢁ
CHꢁCHÃ
CHꢁCHÃ
3
/
1
1
2
3
Ã
/
CHꢁ
CH
/
/C
6
H
5
/
Ã
/
2
2
Ã
/
C
6
H
5
/
1
4
b
Ã
/
3
/
CHÃ
/
C
6
H
5
/
1
1
5
6
Ã
/
/
/C
6
H
H
4
-4-NO
-4-N(CH
2
/
b
Ã
/
/
/C
6
4
3
)
2
/
a
Recrystallized from acetic acid.
Recrystallized from dimethylformamide.
b
ArH), 8.38 (d, 1H, ArH), 7.88 (d, 2H, ArH), 7.96ꢀ
/
7.83
2.3.7. 2-{[(1E)-(2-carboxyphenyl)methylene]amino}-
1-oxo-1,2-dihydroisoquinoline-4-carboxylic acid (9)
(
m, 1H, ArH), 7.67 (t, 1H, ArH), 7.52 (d, 2H, ArH).
1
H NMR (DMSO-d ): d 13.24 (s broad, 2H, COOH),
6
9
.86 (s, 1H, CHÄ
/
N), 8.86 (d, 1H, ArH), 8.50 (s, 1H,
7.57 (m, 6H, ArH).
2
.3.3. 2-{[(1E)-(2-chlorophenyl)methylene]amino}-1-
oxo-1,2-dihydroisoquinoline-4-carboxylic acid (5)
ArH), 8.35 (d, 1H, ArH), 8.19ꢀ
/
1
H NMR (DMSO-d ): d 13.27 (s broad, 1H, COOH),
6
2
.3.8. 2-{[(1E)-(4-hydroxyphenyl)methylene]amino}-
9
.91 (s, 1H, CHÄ
/
N), 8.89 (d, 1H, ArH), 8.55 (s, 1H,
7.59 (m, 6H, ArH).
1
-oxo-1,2-dihydroisoquinoline-4-carboxylic acid (10)
1
H NMR (DMSO-d ): d 12.97 (s broad, 1H, COOH),
6
ArH), 8.39 (d, 1H, ArH), 8.23ꢀ
/
9
.82 (s broad, 1H, ArÃ
/
OH), 9.03 (s, 1H, CHÄ
/
N), 8.85
2.3.4. 2-{[(1E)-(4-bromophenyl)methylene]amino}-1-
oxo-1,2-dihydroisoquinoline-4-carboxylic acid (6)
(d, 1H, ArH, 8 Hz), 8.40 (s, 1H, ArH), 8.33 (d, 1H, ArH,
8.4 Hz), 7.89 (d, 2H, ArH, 9 Hz), 7.92ꢀ7.78 (m, 1H,
ArH), 7.61 (t, 1H, ArH, 7.2 Hz), 7.11 (d, 2H, ArH, 8.6
Hz).
/
1
H NMR (DMSO-d ): d 13.09 (s broad, 1H, COOH),
6
9
.64 (s, 1H, CHÄ
/
N), 8.91 (d, 1H, ArH), 8.47 (s, 1H,
7.85
m, 1H, ArH), 7.71 (t, 1H, ArH), 7.67 (d, 2H, ArH).
ArH), 8.41 (d, 1H, ArH), 7.82 (d, 2H, ArH), 7.98ꢀ
(
/
2.3.9. 2-{[(1E)-(4-methoxyphenyl)methylene]amino}-
1-oxo-1,2-dihydroisoquinoline-4-carboxylic acid (11)
1
H NMR (DMSO-d ): d 12.97 (s broad, 1H, COOH),
6
2.3.5. 2-{[(1E)-(2-bromophenyl)methylene]amino}-1-
oxo-1,2-dihydroisoquinoline-4-carboxylic acid (7)
9
1
9
.09 (s, 1H, CHÄ
H, ArH), 8.35 (d, 1H, ArH, 8.4 Hz), 7.91 (d, 2H, ArH,
Hz), 7.94ꢀ7.79 (m, 1H, ArH), 7.63 (t, 1H, ArH, 7.2
/
N), 8.87 (d, 1H, ArH, 8 Hz), 8.41 (s,
1
H NMR (DMSO-d ): d 13.31 (s broad, 2H, COOH),
6
/
9
.96 (s, 1H, CHÄ
/
N), 8.92 (d, 1H, ArH), 8.59 (s, 1H,
7.63 (m, 6H, ArH).
Hz), 7.12 (d, 2H, ArH, 8.6 Hz), 3.86 (s, 3H, OCH3)
ArH), 8.43 (d, 1H, ArH), 8.29ꢀ
/
2.3.10. 1-oxo-2-{[(1E,2E)-3-phenylprop-2-
enylidene]amino}-1,2-dihydroisoquinoline-4-carboxylic
2.3.6. 2-{[(1E)-(4-nitrophenyl)methylene]amino}-1-
oxo-1,2-dihydroisoquinoline-4-carboxylic acid (8)
acid (12)
1
1
H NMR (DMSO-d ): d 13.25 (s broad, 1H, COOH),
6
H NMR (DMSO-d ): d 12.95 (s broad, 1H, COOH),
6
9
.71 (s, 1H, CHÄ
ArH), 8.39 (d, 1H, ArH), 8.11 (d, 2H, ArH), 7.99ꢀ
m, 1H, ArH), 7.69 (t, 1H, ArH), 8.23 (d, 2H, ArH).
/
N), 8.92 (d, 1H, ArH), 8.46 (s, 1H,
8.85 (d, 1H, CHÄ
1H, ArH), 8.23 (dd, 1H, ArH, 8.6, 1.2 Hz), 7.80ꢀ
/
N, 9.27 Hz), 8.63 (d, 1H, ArH), 8.25 (s,
/
7.83
/7.20
(
(m, 1H, ArH), 7.66ꢀ7.57 (m, 2H, ArH), 7.54ꢀ7.43 (m,
/
/

1220
N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ1225
/
1
H, ArH), 7.35ꢀ
C, 15.62 Hz), 7.10 (dd, 1H, ArCHÄ
5.62, 9.27 Hz).
/
7.24 (m, 3H, ArH), 7.35 (d, 1H,
2.5. General procedure for synthesis of N-arylenamine
ester derivatives (18ꢀ31)
ArCHÄ
1
/
/
CH Ã
/
,
/
The appropriate aldehydes (3 mmol), was added to a
solution of 2 (2 mmol) in 25 ml of acetic acid, and was
heated for 30 min under reflux. The mixture obtained
was cooled to r.t. and the precipitate was collected by
filtration. Afterward the solid was washed with water
and was crystallised from the opportune solvents.
Yields, melting points and crystallization solvents are
reported in Table 2.
2
1
.3.11. 1-oxo-2-{[(1E)-3-phenylpropylidene]amino}-
,2-dihydroisoquinoline-4-carboxylic acid (13)
H NMR (DMSO-d ): d 12.96 (s broad, 1H, COOH),
6
1
8
.84 (d, 1H, ArH), 8.48 (t, 1H, CHÄ
/N), 8.30 (d, 1H,
ArH), 8.21 (s, 1H, ArH), 7.81 (t, 1H, ArH), 7.58 (t, 1H,
ArH), 7.28ꢀ7.14 (m, 5H, ArH), 3.02ꢀ2.91 (m, 2H, ArÃ
CH2Ã), 2.86ꢀ2.74 (m, 2H, ÃCH2ÃCÄN).
/
/
/
/
/
/
/
/
2.5.1. Methyl 1-oxo-2-{[(1E)-phenylmethylene]-
amino}-1,2-dihydroisoquinoline-4-carboxylate (18)
2.3.12. 2-{[(1E,2E)-2-methyl-3-phenylprop-2-
enylidene]amino}-1-oxo-1,2-dihydroisoquinoline-4-
1
H NMR (DMSO-d ): d 9.22 (s, 1H, CHÄ
/
N), 8.75 (d,
6
1
7
H, ArH), 8.48 (s, 1H, ArH), 8.36 (d, 1H, ArH), 7.98ꢀ
/
carboxylic acid (14)
1
.81 (m, 3H, ArH), 7.94ꢀ
/
7.79 (m, 3H, ArH), 7.77ꢀ7.50
/
H NMR (DMSO-d ): d 12.99 (s broad, 1H, COOH),
6
(
m, 4H, ArH), 3.85 (s, 3H, Ã
/
COOCH3).
8
.90 (s, 1H, CHÄ
ArH), 8.33 (d, 1H, ArH), 7.83 (t, 1H, ArH), 7.57ꢀ
m, 6H, ArH), 7.25 (s, 1H, ArH), 2.21 (s, 3H, CH3ÃCÄ
/
N), 8.86 (d, 1H, ArH), 8.35 (s, 1H,
7.35
).
/
2.5.2. Methyl 2-{[(1E)-(4-chlorophenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
(
/
/
(
19)
1
2.3.13. 2-{[(1E,2E)-3-(2-nitrophenyl)prop-2-
enylidene]amino}-1-oxo-1,2-dihydroisoquinoline-4-
H NMR (DMSO-d ): d 9.57 (s, 1H, CHÄ
/
N), 9.03 (d,
6
1
2
H, ArH), 8.57 (s, 1H, ArH), 8.52 (d, 1H, ArH), 8.01 (d,
H, ArH), 8.01ꢀ7.96 (m, 1H, ArH), 7.79 (t, 1H, ArH),
COOCH3).
carboxylic acid (15)
1
/
H NMR (DMSO-d ): d 13.01 (s broad, 1H, COOH),
6
7.66 (d, 2H, ArH), 3.85 (s, 3H, Ã
/
9
1
7
.10 (d, 1H, CHÄ
H, ArH), 8.33 (d, 1H, ArH), 8.12ꢀ
.80 (d, 1H, ArCHÄC, 15.8 Hz), 7.85ꢀ
7.60 (m, 3H, ArH), 7.24 (dd, 1H, ArCHÄ
, 15.8, 9.4 Hz).
/
N, 9.4 Hz), 8.84 (d, 1H, ArH), 8.36 (s,
8.02 (m, 2H, ArH),
7.75 (m, 2H,
/
2
.5.3. Methyl 2-{[(1E)-(2-chlorophenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
20)
/
/
ArH), 7.70ꢀ
CH Ã
/
/
(
1
/
H NMR (DMSO-d ): d 10.03 (s, 1H, CHÄ
/
N), 9.02
d, 1H, ArH), 8.69 (s, 1H, ArH), 8.53 (d, 1H, ArH),
6
(
8
.36ꢀ
/
7.73 (m, 6H, ArH), 3.87 (s, 3H, Ã
/
COOCH3).
2
.3.14. 2-({(1E,2E)-3-[4-(dimethylamino)phenyl]
prop-2-enylidene}amino)-1-oxo-1,2-dihydroisoquinoline-
2.5.4. Methyl 2-{[(1E)-(4-bromophenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
4
-carboxylic acid (16)
1
H NMR (DMSO-d ): d 12.94 (s broad, 1H, COOH),
6
(
21)
8
1
7
6
.86 (d, 1H, ArH), 8.76 (d, 1H, CHÄ
H, ArH), 8.29 (s, 1H, ArH), 7.81 (t, 1H, ArH), 7.64ꢀ
.50 (m, 3H, ArH), 7.28 (d, 1H, ArCHÄC, 15.8 Hz),
.92 (dd, 1H, ArCHÄCH Ã, 15.8, 9.4 Hz), 6.72 (d, 2H,
/N, 9.4 Hz), 8.31 (d,
1
H NMR (DMSO-d ): d 9.78 (s, 1H, CHÄ
/
N), 9.03 (d,
H, ArH), 8.61 (s, 1H, ArH), 8.55 (d, 1H, ArH), 7.94 (d,
H, ArH), 8.11ꢀ7.98 (m, 1H, ArH), 7.85 (t, 1H, ArH),
.80 (d, 2H, ArH), 3.87 (s, 3H, ÃCOOCH3).
6
/
1
2
7
/
/
/
/
/
ArH), 2.97 (s, 6H, N(CH ) ).
3
2
2.5.5. Methyl 2-{[(1E)-(2-bromophenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
2.4. Synthesis of 4-acethyl-2-aminoisoquinolin-1-(2H)-
one (17)
(22)
1
H NMR (DMSO-d ): d 10.09 (s, 1H, CHÄ
/
N), 9.04
6
A solution of 2 (10.2 g, 50 mmol) in 100 ml of
methanol 10% H SO was refluxed for 2 h. After cooled
to r.t. an aqueous solution of saturated Na CO was
(d, 1H, ArH), 8.72 (s, 1H, ArH), 8.57 (d, 1H, ArH),
8.43ꢀ7.75 (m, 6H, ArH), 3.87 (s, 3H, ÃCOOCH3).
/
/
2
4
2
3
added and the white precipitate was collected and
washed with water until to neutral pH. The solid was
finally crystallised from absolute ethanol to yield 7.74 g
2.5.6. Methyl 2-{[(1E)-(4-nitrophenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
(23)
1
1
(
71%) of 17. H NMR (DMSO-d ): d 8.79 (d, 1H, ArH),
6
H NMR (DMSO-d ): d 9.85 (s, 1H, CHÄ
/
N), 9.06 (d,
6
8
7
3
.29 (d, 1H, ArH), 8.26 (s, 1H, ArH), 7.79 (t, 1H, ArH),
.57 (t, 1H, ArH), 6.49 (s broad, 2H, ÃNH ), 3.87 (s,
H, ÃCOOCH ).
1H, ArH), 8.60 (s, 1H, ArH), 8.54 (d, 1H, ArH), 8.27 (d,
2H, ArH), 8.13ꢀ7.96 (m, 1H, ArH), 7.83 (t, 1H, ArH),
8.37 (d, 2H, ArH), 3.88 (s, 3H, ÃCOOCH3).
/
/
2
/
/
3

N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ
/1225
1221
Table 2
Structures, yields and melting points of the prepared quinazolinones derivatives
Compound
R
Yield (%)
Melting point (8C)
Formula
a
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Ã
/
C
C
C
C
C
C
C
C
C
6
6
6
6
6
6
6
6
6
H
H
H
H
H
H
H
H
H
5
4
4
4
4
4
4
4
4
78
82
85
86
82
83
77
74
81
95
84
69
88
69
135ꢀ
198ꢀ
183ꢀ
206ꢀ
176ꢀ
257ꢀ
272ꢀ
263ꢀ
222ꢀ
158ꢀ
162ꢀ
158ꢀ
212ꢀ
147ꢀ
/
7
9
4
7
7
9
4
4
4
60
3
9
4
9
C
C
C
C
C
C
C
C
C
C
C
C
C
C
18
H
18
H
17
H
18
H
17
H
18
H
17
H
18
H
17
H
20
H
17
H
17
H
17
H
17
H
14
N
13
N
12
N
13
N
12
N
13
N
12
N
14
N
12
N
15
N
12
N
12
N
12
N
12
N
2
2
2
2
2
3
2
2
2
2
2
2
2
2
O
3
O
3
O
3
O
3
O
3
O
5
O
3
O
4
O
3
O
3
O
3
O
3
O
3
O
3
a
a
a
a
a
a
a
a
a
a
a
a
a
Ã
/
-4-Cl
-2-Cl
-4-Br
-2-Br
-4-NO
/
Cl
Br
Ã
/
/
Ã
/
/
Ã
/
/
Ã
/
2
/
Ã
/
-2-COOH
-4-OH
/
Ã
/
/
Ã
/
-4-OCH
CHÃ
CH
C(CH )ꢁ
CHꢁCHÃ
CHꢁCHÃ
3
/
Ã
/
CHꢁ
CH
/
/C
6
H
5
/
Ã
/
2
2
Ã
/
C
6
H
5
/
Ã
/
3
/
CHÃ
/
C
6
H
5
/
Ã
/
/
/C
6
H
H
4
-4-NO
-4-N(CH
2
/
Ã
/
/
/C
6
4
3
)
2
/
a
Recrystallized from dimethylformamide.
2
2
.5.7. 2-((E)-{[4-(methoxycarbonyl)-1-oxoisoquinolin-
(1H)-yl]imino}methyl)benzoic acid (24)
H NMR (DMSO-d ): d 13.26 (s broad, 1H, COOH),
6
ArH, 8.6, 1.2 Hz), 7.92ꢀ
(m, 2H, ArH), 7.69ꢀ7.59 (m, 1H, ArH), 7.53ꢀ
3H, ArH), 7.48 (d, 1H, ArCHÄC, 15.62 Hz), 7.23 (dd,
1H, ArCHÄCH Ã, 15.62, 9.27 Hz), 3.87 (s, 3H, Ã
COOCH ).
/
7.82 (m, 1H, ArH), 7.79ꢀ
/
7.70
/
/7.42 (m,
1
/
9
.99 (s, 1H, CHÄ
/
N), 8.97 (d, 1H, ArH), 8.62 (s, 1H,
7.69 (m, 6H, ArH), 3.87
/
/
/
ArH), 8.49 (d, 1H, ArH), 8.33ꢀ
/
3
(
s, 3H, Ã/COOCH3).
2.5.11. Methyl 1-oxo-2-{[(1E)-3-phenylpropylidene]-
amino}-1,2-dihydroisoquinoline-4-carboxylate (28)
2
.5.8. Methyl 2-{[(1E)-(4-hydroxyphenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
1
H NMR (DMSO-d ): d 8.96 (d, 1H, ArH), 8.60 (t,
6
(
25)
1
H, CHÄ
/
N, 4.6/9.2 Hz), 8.41 (d, 1H, ArH), 8.32 (s, 1H,
1
H NMR (DMSO-d ): d 9.96 (s broad, 1H, ArÃ
/
OH),
N), 8.97 (d, 1H, ArH, 8 Hz), 8.54 (s,
H, ArH), 8.47 (d, 1H, ArH, 8.4 Hz), 8.03 (d, 2H, ArH,
Hz), 8.05ꢀ7.91 (m, 1H, ArH), 7.75 (t, 1H, ArH, 7.2
COOCH3).
6
ArH), 7.93 (t, 1H, ArH), 7.70 (t, 1H, ArH), 7.40ꢀ
/7.27
9
1
9
.17 (s, 1H, CHÄ
/
(
2
m, 5H, ArH), 3.87 (s, 3H, Ã
/
COOCH ), 3.11ꢀ
/
3.01 (m,
N)
3
H, ArÃ
/
CH2Ã
/
), 2.95ꢀ
/
2.82 (m, 2H, Ã
/
CH2Ã
/
CÄ
/
/
Hz), 7.25 (d, 2H, ArH, 8.6 Hz), 3.86 (s, 3H, Ã
/
2.5.12. Methyl 2-{[(1E,2E)-2-methyl-3-phenylprop-2-
enylidene]amino}-1-oxo-1,2-dihydroisoquinoline-4-
2.5.9. Methyl 2-{[(1E)-(4-methoxyphenyl)methylene]-
amino}-1-oxo-1,2-dihydroisoquinoline-4-carboxylate
carboxylate (29)
1
H NMR (DMSO-d ): d 9.01 (s, 1H, CHÄ
/
N), 8.99 (d,
6
(
26)
1
1H, ArH), 8.47 (s, 1H, ArH), 8.45 (d, 1H, ArH), 7.96 (t,
H NMR (DMSO-d ): d 9.22 (s, 1H, CHÄ
/
N), 8.98 (d,
H, ArH, 8 Hz), 8.52 (s, 1H, ArH), 8.45 (d, 1H, ArH,
.4 Hz), 8.04 (d, 2H, ArH, 9 Hz), 8.04ꢀ7.93 (m, 1H,
6
1H, ArH), 7.69ꢀ/7.47 (m, 6H, ArH), 7.36 (s, 1H, ArH),
1
8
3
.86 (s, 3H, ÃCOOCH ), 2.31 (s, 3H, CH Ã
/
/
CÄ).
/
3
3
/
ArH), 7.77 (t, 1H, ArH, 7.2 Hz), 7.25 (d, 2H, ArH, 8.6
Hz), 3.89 (s, 3H, ÃCOOCH ), 3.86 (s, 3H, ÃOCH3)
/
/
2.5.13. Methyl 2-{[(1E,2E)-3-(2-nitrophenyl)prop-2-
enylidene]amino}-1-oxo-1,2-dihydroisoquinoline-4-
3
2
.5.10. Methyl 1-oxo-2-{[(1E,2E)-3-phenylprop-2-
enylidene]amino}-1,2-dihydroisoquinoline-4-carboxylate
27)
carboxylate (30)
1
H NMR (DMSO-d ): d 9.22 (d, 1H, CHÄ
/
N, 9.4 Hz),
6
(
8.95 (d, 1H, ArH), 8.48 (s, 1H, ArH), 8.46 (d, 1H, ArH),
8.24ꢀ8.15 (m, 2H, ArH), 7.92 (d, 1H, ArCHÄC, 15.8
Hz), 7.98ꢀ7.87 (m, 2H, ArH), 7.82ꢀ7.71 (m, 3H, ArH),
1
H NMR (DMSO-d ): d 8.96 (d, 1H, CHÄ
/
N, 9.27
/
/
6
Hz), 8.76 (d, 1H, ArH), 8.39 (s, 1H, ArH), 8.36 (dd, 1H,
/
/

1222
N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ1225
/
7
COOCH ).
.35 (dd, 1H, ArCHÄ
/
CH Ã
/
, 15.8, 9.4 Hz), 3.85 (s, 3H, Ã
/
DMEM without phenol red was replaced in each well.
After 90 min incubation at 37 8C, the overlay was
removed and isopropanol (100 ml) was added; plates
were then mixed twice to dissolve the dark blue crystals.
The optical density (OD) was read at 540 and 690 nm on
a Titertek Multiscan MCC/340, within 15 min of adding
the isopropanol [17,18]. The absorbance at 690 nm was
automatically subtracted from the absorbance at 540
nm, so as to eliminate the effect of non-specific
absorption. Cell viability values obtained in the presence
of the compounds were expressed as the percentage of
those obtained in untreated controls and were calculated
by the following formula:
3
2.5.14. Methyl 2-({(1E,2E)-3-[4-(dimethylamino)-
phenyl]prop-2-enylidene}amino)-1-oxo-1,2-
dihydroisoquinoline-4-carboxylate (31)
1
H NMR (DMSO-d ): d 8.98 (d, 1H, ArH), 8.87 (d,
6
1
H, CHÄ
ArH), 7.94 (t, 1H, ArH), 7.76ꢀ
d, 1H, ArCHÄC, 15.8 Hz), 7.04 (dd, 1H, ArCHÄ
5.8, 9.4 Hz), 6.84 (d, 2H, ArH), 3.84 (s, 3H, Ã
/
N, 9.4 Hz), 8.43 (d, 1H, ArH), 8.42 (s, 1H,
7.61 (m, 3H, ArH), 7.40
CH Ã
/
(
1
/
/
/,
/
COOCH ), 3.02 (s, 6H, N(CH ) ).
3
3 2
2
2
.6. Virology
(
OD) ꢂ (OD)
c t
ꢃ100
(
OD)c
.6.1. Viruses and cells
ECHO virus 9 (Hill strain), Poliovirus 1 (Brunhilde
where (OD) and (OD) indicated the absorbances of the
t
c
strain), Coxsackievirus B1, measles (Edmonston strain)
and adenovirus type 2 were purchased from the Amer-
ican Type Culture Collection (ATCC) and propagated
in human epidermoid carcinoma larynx cells (Hep-2).
Encephalomyocarditis (EMC strain) and Herpes sim-
plex type 1 (F strain) were purchased from the ATCC
and propagated in mouse connective tissue cells (L-929)
and African green monkey kidney cells (Vero), respec-
tively. Cells were kept in a humidified 5% carbon
dioxide atmosphere at 37 8C and grown in Dulbecco
modified Eagle’s Minimum Essential medium (DMEM)
supplemented with 6% heat inactivated fetal calf serum
untreated cell control and the test sample, respectively.
The 50% cytotoxic dose (CC ), calculated by doseꢀ
response curves and linear regression, was expressed as
the concentration of the compound that reduced the
absorbance of the control sample by 50%.
/
5
0
2.6.4. Antiviral activity
The antiviral activity was estimated using a plaque
reduction assay. Confluent cells were grown in 6-well
tissue culture plates and infected with 300 plaque
forming units (PFU) of the virus stock for well. During
and after 1 h of virus adsorption at 37 8C (half hour for
picornavirus), overlay medium containing 1% of methyl-
cellulose with or without the test compound at doses
below CC50 was added. After 24 h of incubation at
ꢂ1
ꢂ1
(
FCS), 200 mg ml of streptomycin and 200 units ml
of penicillin G. For all viruses tested working stocks
were prepared as cellular lysates using DMEM without
FCS (maintenance medium).
37 8C, when the plaques appeared clearly in virus
controls, the overly was removed and cells were stained
with 1% crystal violet in methanol. The number of
visible plaques was then counted under light micro-
scopy. The antiviral activity of each compound was
determined as the percentage decrease in the number of
plaques, which was calculated by the following formula:
2
.6.2. Test compounds
All compounds were dissolved in dimethylsulphoxide
DMSO) and diluted in maintenance medium to achieve
(
the final concentration need. Dilution of the test
compounds contained a maximal concentration of
0
.01% DMSO, which was not toxic to cell lines.
no: of plaques (control) ꢂ no: of plaques (test)
ꢃ100
2
.6.3. Cell viability
The cytotoxicity of the test compounds was evaluated
no of plaques (control)
by measuring the effect produced on cell morphology
and cell growth. Cell monolayers were prepared in 24-
well tissue culture plates and exposed to various
concentrations (mM) of the compounds. Plates were
checked by light microscopy after 12, 24 and 48 h.
Cytotoxicity was scored as morphological alterations
The compound concentration required to inhibit virus
plaque formation by 50% was expressed as IC50 and
calculated by doseꢀ
/
response curves and linear regres-
sion.
(
rounding up, shrinking and detachment). The viability
3
. Results and discussion
of the cells was determined by the 3-(4,5-dimethylthia-
zol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)
method. Briefly, Hep-2, L929 and Vero cells were
prepared in 96-well tissue culture plates and serial
concentrations of the compounds were added. After
3.1. Chemistry
Twenty-eight new isoquinolin-4-one derivatives, re-
ported in Tables 1 and 2, were synthesized and their
ꢂ1
incubation for 48 h at 37 8C, MTT (0.5 mg ml ) in

N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ
/1225
1223
inhibition of MV replication were evaluated. The
synthetic pathway (Scheme 1) starts from the isocou-
marin-4-carboxylic acid (1) previously described [15].
Reaction of 1 with hydrazine monohydrate in absolute
ethanol under reflux for 1 h yielded the corresponding 2-
amino-1-oxo-1,2-dihydroisoquinoline-4-carboxylic acid
due to the H-1? produced NOE signals for H-3 proton of
the dihydroisoquinoline ring and for the aromatic H-2?/
H-6? protons with values in the range 2ꢀ
/
5 and 16ꢀ21%,
/
respectively.
3.2. Antiviral activity and SAR studies
(
2). The enamines 3ꢀ
compound 2 with the suitable aldehydes, commercially
available, in acetic acid. Compounds 10ꢀ15 were pre-
/
8 were obtained by treating
A series of new isoquinoline analogues were evaluated
/
for anti-measles activity using Edmonston strain of MV.
All compounds were evaluated with respect to the
inhibition of MV in human epidermoid carcinoma
larynx cells (Hep-2). Table 3 shows the 50% cytotoxic
dose values (CC ), the compound concentrations
pared in a similar way from the compound 9, obtained
by esterification of 2 with methanol in 10% H SO .
2
4
All the synthesized compounds were obtained in the E
or E,E configurations. The stereochemistry of the
5
0
propenylideneamino chain for compounds 12ꢀ
/
16 and
required to inhibit virus plaque formation by 50%
IC ) and the selectivity indexes (SI) calculated dividing
CC50 by IC50.
2
7ꢀ31 (Tables 1 and 2) was assigned as all trans on the
/
(
5
0
1
basis of H NMR coupling constants analysis as well as
nuclear Overhauser effects (NOE) enhancement experi-
ments. The coupling constant between hydrogen atom
The appearance of anti-MV activity was obtained
with the introduction of phenylmethanimine side chain
on the exocyclic nitrogen of the inactive derivative 2, to
give 1-oxo-2-{[(1E)-phenylmethylene]amino}-1,2-dihy-
droisoquinoline-4-carboxylic acid (3) with an IC50 of
H-2? and H-3? (15ꢀ16 Hz) are indicative of 2? trans
/
geometry. The geometry of the 1? double bond is clearly
established by NOE. In these studies, NOE cross peaks
were observed between the H-1? proton and the proton
H-3 of the dihydroisoquinoline ring with values in the
45 mM and a CC50 of 100 mM. Therefore, our medicinal
chemistry effort was directed toward the effect of
substituents on the phenyl ring of phenylmethanimine
moiety with the intention to examine the effect of
electron-donating and electron-withdrawing groups on
the antiviral activity.
range 8ꢀ
/
12%. In addition, the irradiation of H-1? proton
resonances intensified the H-3? signal (16ꢀ
/
19%), identi-
fying unequivocally the dominance of planar or near-
planar s-trans conformations of the propenylidenea-
mino chain.
An inspection of data reported in Table 3 reveals that
the introduction of electron-withdrawing group in 4-
position of the phenyl ring increased the anti-MV
activity. The most active compound was the 4-bromo
The geometry of the 1? double bond in the derivative
3
interpretation of NOE data. Irradiation of the singlet
ꢀ
/
11 and 18ꢀ/26 (Tables 1 and 2) was clearly assigned by
2 2 2 4
Scheme 1. (a) H NNH ; (b) MeOH, H SO ; (c) R-phenyl-CHO.

1224
N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ1225
/
Table 3
Antiviral activity and SI of isoquinoline derivatives
a,c
b,c
d
CC50 (mM)
IC50 (mM)
SI
Compound
R
HEp-2 L-929/VERO
Measles virus
3
4
5
6
7
8
9
Ã
/
C
C
C
C
C
C
C
C
C
6
6
6
6
6
6
6
6
6
H
H
H
H
H
H
H
H
H
5
4
4
4
4
4
4
4
4
100
100
30
48.0
25.0
2
4
Ã
/
-4-Cl
-2-Cl
-4-Br
-2-Br
-4-NO
Ã
/
ꢀ
/
30
15.0
30
42.0
1
Ã
/
80
30
5
Ã
/
ꢀ
/
1
Ã
/
2
250
600
300
500
100
750
500
150
150
6
Ã
/
-2-COOH
-4-OH
ꢀ
/
600
300
500
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
Ã
/
ꢀ
/
1
Ã
/
-4-OCH
CHÃ
CH
C(CH )ꢁ
CHꢁCHÃ
CHꢁCHÃ
3
ꢀ/
1
Ã
/
CHꢁ
CH
/
/C
6
H
5
12.5
8
Ã
/
2
2
Ã
/
C
6
H
5
ꢀ/750
1
Ã
/
3
/
CHÃ
/
C
6
H
5
10.0
25.0
50
6
Ã
/
/
/C
6
H
4
-4-NO
-4-N(CH
2
Ã
/
/
/C
6
H
4
3
)
2
ꢀ/150
1
a
b
c
CC50: concentration which inhibited cell growth by 50% as compared with control cultures.
IC50: concentration which inhibited virus plaque formation by 50%.
Values are mean9
/
0.5 SD (maximal standard deviation estimated) of three separate assays.
d
SI was determined for the effective compounds dividing CC50 by IC50
.
ymethyl moiety of the 4-chloro-phenyl-derivative
UK2054, that was reported active against MV, whereas,
the corresponding 4-methoxy-phenyl- analogous UK
derivative 6. In this series the increase of the anti-MV
activity follow the order 4-Brꢀ4-Cl (4)ꢀ4-NO2 (8)
with IC50 of 15, 25 and 42 mM, respectively. For these
latter three derivatives the activity is well separated from
their cytotoxicity, as underlined by their respective SI.
/
/
2371 was totally inactive (Fig. 1) [19].
With the aim to further explore the structural
requirements for an optimum interaction with the viral
target, we synthesized the vinylogous compounds 12ꢀ16
The SI value followed the order 4-NO (8)ꢀ
/
-4-Br (6)ꢀ
/
2
/
4
-Cl (4). Interestingly, the meta-analogues (5, 7) showed
listed in Table 1. The insertion of a vinyl group is
beneficial for the activity, as is demonstrated by
vinylogous compound 12, 14 and 15. Compound 12,
vinylogous of compound 3, maintain the same CC50
an increase in the cytotoxicity and a loss of activity at
concentrations lower than their respective the CC50
values.
Despite their lower cytotoxicity, derivatives with
electron-donor groups -4-OH (10) -4-OCH (11) at the
position 4 in the phenyl ring showed no activity against
(
100 mM) of the parent compound and showed a
twofold increase in the anti-MV activity (from 25 to
2.5 mM) with a resulting doubling of the SI from 4 to 8.
Compound 15, vinylogous of compound 8, showed a
.68-fold increase in the anti-MV activity as highlighted
3
1
MV. It is interesting to note that the inactive -4-OCH3
derivative (11), has a calculated log D value comprised
between the one of the active phenyl (3) and that of 4-
1
by the IC50 reduction from 42 to 25 mM. The vinylogous
15 was more cytotoxic with respect to the parent
compound 8 with a 60% decrease of CC50 (from 250
to 150 mM).
NO -phenyl (8) derivatives (log D at pH 7.4ꢁ
/0.0099,
2
ꢂ
/
0.13 and ꢂ/0.22, respectively). Therefore, for the
above mentioned compounds (3ꢀ11), the electronic
/
factor seems to be more important when compared to
lipophilicity in improving the recognition at the biolo-
gical target. The correlation between anti-MV activity
and the electron-withdrawing effect of the substituents
on the phenyl ring outlined in this study is in agreement
with literature data. In fact, the same trend was
observed for the aromatic substituents of the phenox-
Regarding the electronic effect of substituents at the
4-position of aromatic ring in the vinylogous derivatives
12ꢀ
11, in fact, the non-substituted compounds 12 and 14
together with the electron-withdrawing substitute deri-
vative 15 were active. On the contrary, the introduction
of an electron donor group in the 4-position like in the
/
16, we observed the same trend as the analogues 3ꢀ
/

N.A. Santagati et al. / Il Farmaco 58 (2003) 1217ꢀ
/1225
1225
4
-N(CH ) derivative 16 determined a loss of antiviral
2
References
3
activity. In addition, as above discussed for the com-
pound 11, the 4-N(CH3)2 derivative 16, despite of
similar calculated log D value with respect to non-
[
[
1] M. Manchester, D. Naniche, T. Steele, CD46 as a measles virus
receptor form follow function, J. Virol. 274 (2000) 5ꢀ10.
2] H. Kawashima, T. Mori, Y. Kashiwagi, K. Takekuma, A.
Hoshika, A. Wakefield, Detection and sequencing of measles
virus from peripheral mononuclear cells from patients with
/
substituted compounds 12 (log D at pH 7.4ꢁ
.85, respectively), is inactive. Therefore, also for
vinylogous 12ꢀ16 the electronic factor seems to be
/0.98 and
0
/
inflammatory bowels and autism, Dig. Dis. Sci. 45 (2000) 723ꢀ
/
more relevant with respect to lipophilicity. Moreover,
the saturated derivative 13, despite its lowest cytotoxi-
city (CC50 750 mM) was inactive. Interestingly, the
729.
3] M.A. Afzal, P.D. Minor, G.C. Schild, Clinical safety issues of
[
[
[
measles, mumps and rubella vaccines, Bull. World Health Organ.
7
4] J.S. Rota, P.A. Rota, S.D. Redd, S.C. Redd, S. Pattamadilok,
8 (2000) 199ꢀ204.
/
insertion of a Ã/CH group in the double bound in
3
position 1 of (1E,2E)-3-phenylprop-2-enylidene moiety
seemed to optimize the antiviral activity, since the
compound 14 showed the highest anti-MV activity (10
mM) and exhibited highest SI value of 50.
W.J. Bellini, Genetic analysis of measles viruses isolated in the
United States, 1995ꢀ
/
1996, J. Infect. Dis. 177 (1998) 204ꢀ208.
/
5] G. Banks, H. Fernandez, Clinical use of ribavirin in measles: a
summarized review, in: A.D. Smith, V. Knight, J.A.D. Smith
(
Eds.), Clinical Applications of Ribavirin, Academic Press Inc,
Taken together these experimental data for the series
New York, 1980, pp. 203ꢀ209.
/
1
2ꢀ16, support two implications: the importance of the
/
[
6] A.L. Forni, N.W. Schluger, R.B. Roberts, Severe measles
pneumonitis in adults: evaluation of clinical characteristics and
therapy with intravenous ribavirin, Clin. Infect. Dis. 19 (1994)
transmission of electronic effects between the 1-oxo-2-
dihydroisoquinoline nucleus and the aromatic ring, and/
or the relevance planar or near-planar s-trans conforma-
tion of the propenylideneamino chain.
4
54ꢀ
7] S. Gururangan, R.F. Stevens, D.J. Morris, Ribavirin response in
measles pneumonia, J. Infect. Dis. 20 (1990) 219ꢀ221.
8] L.A. Ross, S.K. Kwang, W.H. Mason, Jr., E. Gomperts,
Successful treatment of disseminated measles in a patient with
acquired immunodeficiency syndrome: consideration of antiviral
/462.
[
[
/
All ester derivatives 18ꢀ31 were not active against
/
MV. The loss of activity upon esterification could be
due to the strong reduction of water solubility at pH 7.4
of these compounds that, in turn, can reduce the
intracellular bioavailability. In fact, the calculated water
and passive immunotherapy, Am. J. Med. 88 (1984) 313ꢀ314.
/
[
9] S.W. Stogner, J.W. King, C. Black-Payne, J. Bocchini, Ribavirin
and intravenous immune globulin therapy for measles pneumonia
solubility values for the acid (3ꢀ
/
16) and the esters (18ꢀ
1) derivatives were in the ranges 0.13ꢀ3.53 and 9.2ꢃ
g l , respectively, with a solubility
250 fold.
/
in HIV infection, South. Med. J. 141 (1993) 1415ꢀ1418.
/
3
1
/
/
[
10] T.J. Feldstein, J.L. Swegarden, G.F. Atwood, C.D. Peterson,
ꢂ4
ꢂ2
ꢂ1
0
ꢀ
/
1.4ꢃ/10
Ribavirin therapy: implementation of hospital guidelines and
effect on usage and cost of therapy, Pediatrics 96 (1995) 14ꢀ17.
/
reduction for ester compounds of 140ꢀ
/
[
[
11] E.D. Marquardt, Cost of ribavirin therapy for respiratory
Exceptions for both series were represented by the 2-
COOH-phenyl derivatives (9 and 24) that have good
calculated water solubility but are both inactive. Alter-
natively, the lack of activity of the esters derivatives
could also suggests that the presence of a carboxylic acid
group is essential for the antiviral activity.
syncytial virus infection, J. Pediatr. 126 (1995) 847.
12] M.G. Ottolini, V.G. Hemming, Prevention and treatment recom-
mendations for respiratory syncytial virus infection*
and clinical experience 40 years after discovery, Drugs 54 (1997)
867ꢀ884.
/background
/
[
13] P.R. Wyde, D.K. Moore-Poveda, E. De Clercq, J. Neyts, A.
Matsuda, N. Minakawa, E. Guzman, B.E. Gilbert, Use of cotton
rats to evaluate the efficacy of antivirals in treatment of measles
All the compounds (3ꢀ
for their antiviral activity against RNA (polio 1, ECHO
, Coxsackie Bl, EMC) and DNA (adeno 2, HSV-1)
viruses in Hep-2 cells or mouse connective tissue cells
L-929) and African green monkey kidney cells (Vero).
/
16 and 18ꢀ
/
31) were also tested
virus infections, Antimicrob. Agents Chemother. 44 (2000) 1146ꢀ
152.
[14] A.S. Beare, M.L. Bynoe, D.A. Tyrrell, Prophylaxis of influenza
with a synthetic isoquinoline, Lancet 20 (1968) 843ꢀ845.
15] D.L. Swallow, Antiviral agents, Prog. Drug Res. 22 (1978) 267ꢀ
26.
16] N.A. Santagati, E. Bousquet, S. Tirendi, A Caruso, V. Cutuli, M.
Amico-Roxas, Research on isoquinoline derivative*V. Synthesis
/
9
1
/
(
[
[
/
The compounds synthesized in this study displayed an
interesting selectivity against MV since only compound
12 was active against EMC strain with IC50 of 25 mM
and a selectively index of 4.
3
/
and pharmacological evaluation of a series of amid derivatives of
isoquinolin and isocoumarin carbozylic acids, Il. Farmaco. 48
In conclusion, the facile synthesis and the information
(
17] T. Mosmann, Rapid colorimetric assay for cellular growth and
1993) 21ꢀ30 (and references therein cited).
/
obtained from the structureꢀactivity relationship may
/
[
[
constitute the basis for the future development of more
active compounds.
survival: application to proliferation and cytotoxicity assays, J.
Immunol. Methods 65 (1983) 55ꢀ63.
/
18] F. Denizot, R. Lang, Rapid colorimetric assay for cell growth and
survival. Modifications to the tetrazolium dye procedure giving
improved sensitivity and reliability, J. Immunol. Methods 89
Acknowledgements
(
1986) 271ꢀ277.
/
[
19] N.M. Larin, A.S. Beare, M.P. Copping, C.R. McDonald, J.K.
McDougall, B. Roberts, J.B. Smith, Spectrum and characteristics
of the virus-inhibitory action of two isoquinoline derivatives,
The authors are grateful to the Ministero dell’Istru-
zione dell’Universit a` e della Ricerca (MIUR) for
financial assistance.
Antimicrob. Agents Chemother. 7 (1967) 646ꢀ653.
/