Synthesis and evaluation of molluscicidal and larvicidal activities of some novel enaminones derived from 4-hydroxyquinolinones: Part IX

Article abstract of DOI:10.1016/j.bmc.2005.06.038

A series of 10 3-(hetarylaminomethylene)quinolinediones, 12 3-(substituted aminopropenoyl)-4-hydroxyquinolinones, and 10 3-(substituted aminomethylene-5-oxo-pyrazolinyl)-4-hydroxyquinolinones were synthesized as novel enaminones derived from 3-(un)substit

Full text of DOI:10.1016/j.bmc.2005.06.038

Bioorganic & Medicinal Chemistry 13 (2005) 6133–6144
Synthesis and evaluation of molluscicidal and larvicidal activities
of some novel enaminones derived from
4-hydroxyquinolinones: Part IX
Mohamed Abassa,* and Bayaumy B. Mostafab
aDepartment of Chemistry, Faculty of Education, Ain Shams University, Roxy 11757, Cairo, Egypt
bEnvironmental Research Laboratory, Theodor Bilharz Research Institute, Imbaba, Giza, Egypt
Received 8 May 2005; revised 2 June 2005; accepted 13 June 2005
Available online 21 July 2005
Abstract—A series of 10 3-(hetarylaminomethylene)quinolinediones, 12 3-(substituted aminopropenoyl)-4-hydroxyquinolinones,
and 10 3-(substituted aminomethylene-5-oxo-pyrazolinyl)-4-hydroxyquinolinones were synthesized as novel enaminones derived
from 3-(un)substituted 4-hydroxyquinolin-2(1H)-ones in 72–94% yields and assayed for their molluscicidal activities against
Biomphalaria alexandrina and Lymnaea natalensis snails. Some of the tested enaminones presented high molluscicidal activities
(LC50 6 20 ppm). The new compounds showed more potency against hatchability of B. alexandrina egg masses, the infection
rate and prepatent period of the snails. In addition, these derivatives revealed potential larvicidal effects (100% mortality) on
both miracidia and cercariae of Schistosoma mansoni at reduced exposure time. The selected active derivatives were examined
against Daphnia magna and their nontoxic effect at all sublethal, lethal, and higher concentrations suggests that these com-
pounds can play an important role as molluscicides and larvicides with environmental safe properties.
Ó 2005 Elsevier Ltd. All rights reserved.
1. Introduction
as an integrated control scheme including chemothera-
py, molluscicidal, ecological, and biological control
methods.4 Thus, it was reported that a problem of resis-
tance of Schistosoma mansoni to praziquantel had been
sought and further research is needed for exploring
alternative drugs to treat praziquantel-resistant schisto-
somiasis.5 On the other hand, the well-known environ-
mental hazardous effects of the most used
molluscicides, for example, copper sulfate and niclosa-
mide, promoted a considerable and systematic search
for new molluscicides which might provide effective con-
trol agents for snails and be harmless to the nontargeted
beings in the environment.6 Many quinoline alkaloids7
and quinolinone derivatives8 were reported to exhibit
important molluscicidal potency. In addition, atanine,
a quinolinone alkaloid, showed potential activity against
larvae, adults of Caenorhabditis elegans and miracidia,
and cercariae of S. mansoni.9 As a part of our research
work on synthesis of substituted quinolinones attached
with biological properties, we describe the synthesis
and investigation of the molluscicidal and larvicidal
activity of new enaminones derived from 4-hydroxy-
quinolin-2(1H)-ones as potential drug candidates
against schistosomiasis at transmission stages.
Schistosomiasis is the second most imperative tropical
parasitic disease of humans after malaria especially in
the developing world with an estimation that at least
200 million people, in 74 countries, are currently infect-
ed and 600 million are at risk of infection. Annual mor-
tality due to schistosomiasis was estimated at 15,000
deaths/year and the burden of disease at 1.702 million
DALYs lost per year. About 20 million people suffer
several consequences from the disease and 120 million
are symptomatic.1,2 Although the current strategy for
morbidity control is largely based on chemotherapy,2
control of the snail host using molluscicides to stop
transmission cycle is still considered a vital role because
the use of molluscicides in the prophylactic treatment
leads to the rupture of evolutionary lifecycle of the
worm via destructing its intermediate host.3 The success-
ful control program of the disease should be constructed
Keywords: Quinolinone; Enaminone; Molluscicide; Larvicide.
*
Corresponding author. Tel.: +2 010 5689310; fax: +2 02 2581243;
e-mail: quinolinone@yahoo.com
0968-0896/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.bmc.2005.06.038

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2. Results and discussion
4-hydroxyquinolin-2(1H)-ones 3a–d using chloroform
and sodium hydroxide14 afforded the corresponding
aldehydes 6a–d that on condensation with 4-aminoanti-
pyrine (7) in the presence of glacial acetic acid gave 3-
(pyrazolinylaminomethylene)quinolinediones 8a–d in
81–94% yields. The synthesis of 3-(pyridyl or pyrim-
idyl-aminomethylene)quinolinediones 9a–f was conve-
niently achieved in one pot by heating compound 3a
or 3b with the adequate amounts of 2- or 3-aminopyri-
dine or 2-aminopyrimidine and dimethylformamide
dimethylacetal (DMF-DMA) (Scheme 2).
2.1. Synthesis of the compounds
As illustrated in the Scheme 1, compounds 2a–d10,11 and
3a–d12 were prepared by condensation of the proper
N-alkylanilines or diphenylamine with diethyl malonate.
Alkaline hydrolysis of 2a–d furnished the 3-acetylquin-
olinones 4a–d,11 while the hydrazinolysis of 2a,b led to
the formation of 3-(pyrazolinyl)quinolinones 5a,b.13
Compounds 3a–d, 4a–d, and 5a,b were utilized as
synthetic precursors for three groups of enaminone
derivatives. Thus, Riemer–Tiemann formylation of the
3-[3-(Dimethylamino)prop-2-enoyl]-4-hydroxyquinolin-
2(1H)-one derivatives 10a–d were prepared in fair yields
Scheme 1. Reagents and conditions: (i) diethyl malonate, 220 °C, 8 h; (ii) diethyl malonate, PPA, 170–200 °C, 2 h; (iii) NaOH (15 %), reflux, 2 h;
(iv) N2H4ÆH2O, DMF, reflux, 1 h.
Scheme 2. Reagents and conditions: (i) CHCl3, NaOH (15%), reflux, 6 h; (ii) AcOH, reflux, 2 h; (iii) DMF-DMA, toluene, 110 °C, 2 h.

M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
6135
via thermal condensation of their respective 1-substitut-
ed 3-acetylquinolinones 4a–d with DMF-DMA. The
structure of these propenoylquinolinones was assigned
as the E-form, where the coupling constant of the olefin-
ic protons is in the range 13–16 Hz. To obtain other
enaminone derivatives bearing heterocycles of biological
interest, the compounds 10a–d were subjected to react
with 4-aminoantipyrine (7) affording the corresponding
4-hydroxy-3-[3-(pyrazolinylamino)propenoyl]quinoli-
nones 11a–d. The probable product 12 for the later reac-
spectral data which evidently revealed that the product
does not include the N,N-dimethylamino group, a result
which was fortified by the found analytical data. Simi-
larly, reaction of the compounds 10a,b with piperidine
and morpholine as alicyclic secondary amines smoothly
proceeded leading to the corresponding 1-alkyl-3-[3-
(piperidinyl or morpholinyl)propenoyl]quinolinones
13a–d in good yields (Scheme 3).
In analogy to the above methodology, the pyrazolinones
5a,b were subjected to condensation with DMF-DMA
1
tion was definitely excluded on the basis of H NMR
Scheme 3. Reagents and conditions: (i) 4-aminoantipyrine (71), DMF-DMA, toluene, 110 °C, 2 h; (ii) AcOH, reflux, 2 h; (iii) reflux, 2 h.
Scheme 4. Reagents and conditions: (i) DMF-DMA, p-xylene, reflux, 2 h; (ii) AcOH, reflux, 1 h; (iii) 4-aminoantipyrine (7), CH(OEt)3, (CH2OH)2,
110–190 °C, 1 h.

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M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
Table 1. Molluscicidal activity of the enaminone derivatives against Biomphalaria alexandrina and Lymnaea natalensis (10 snails per concentration)
after 24 h exposure at ambient temperature 24 1 °C
Compound
Snail
LC10 (ppm)
LC25 (ppm)
LC50 (ppm)
LC90 (ppm)
Slopea
8a
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
B. alexandrina
L. natalensis
9.24
8.65
7.90
2.01
3.77
—
18.14
13.69
13.69
8.10
28.14
19.31
20.13
14.90
41.19
—
46.83
29.96
32.36
27.96
78.65
—
1.88
1.64
1.74
2.54
2.78
—
9a
9b
21.49
—
10a
10b
10c
14a
14.84
12.91
11.41
4.04
2.66
4.80
11.21
—
30.31
30.31
18.69
10.61
6.11
47.51
40.41
20.20
19.01
15.88
15.80
66.21
—
89.18
59.88
29.00
53.03
34.40
61.10
121.20
—
2.00
1.72
1.38
2.72
2.96
2.99
2.38
—
8.30
37.26
—
a Slope = (LC84/LC50 + LC50/LC16)/2.24
in boiling xylene to give 3-[4-(dimethylaminomethyl-
ene)pyrazolinyl]-4-hydroxyquinolinones 14a,b. Herein
again the dimethylamino group in this enaminone sys-
tem acts as a good leaving group when these two com-
pounds were treated with 2- or 3-aminopyridine or
2-aminopyrimidine in glacial acetic acid to afford the
corresponding 4-(hetarylaminomethyene)pyrazolinones
15a–f in 73–93% yields. A high yield and efficient synthe-
sis of 4-(pyrazolinylaminomethyene)pyrazolinones 16a,b
was achieved via one pot reaction13 of the pyrazolinones
5a,b with 4-aminoantipyrine and triethyl orthoformate
(Scheme 4).
2.2. Molluscicidal assays
Biomphalaria alexandrina is the historically implicated
snail in the transmission of S. mansoni in Egypt.15 In re-
cent years, introduction of Biomphalaria glabrata and
the recognized hybrids of the two species of intermediate
host in Egyptian habitat has been reported.16 For this
reason, B. alexandrina is still a target for molluscicidal
studies. In addition, many reports showed that B. alex-
andrina snails are more tolerant to the action of mollusc-
icides than Bulinus truncatus snails which are also
widespread in Egypt.17 The examination of the new
compounds against B. alexandrina would show their
molluscicidal potency. Thus, Table 1 shows the evalua-
tion of the toxic effect of some new enaminone deriva-
tives on the adult B. alexandrina and Lymnaea
natalensis snails. This table indicates the results of assays
performed with LC10, LC25, LC50, and LC90 (ppm) for
some selected derivatives. The LC50 values in Table 1
indicated high molluscicidal activity of compounds
8a, 9a,b, and 10a–c against B. alexandrina (LC50
15.88–47.51 ppm). The rest of tested compounds esti-
mated LC50 > 100 ppm, and hence they are considered
inactive. Similar behavior for the screened compounds
against L. natalensis snails (LC50 14.90–40.41 ppm)
was observed. The LC50 results revealed that the most
active compounds against B. alexandrina snails are in
the following sequence: 10c > 9a P 10b > 8a > 10a.
Against L. natalensis snails, the order of activity is
9a P 10c > 10b P 8a > 10a. The structure–activity
relationship in the group of compounds 10a–c revealed
Figure 1. Effect of increment of (CH2) units in N-alkyl group of
compounds 10a–c on LC10–50 values as function of activity against (A)
Biomphalaria alexandrina and (B) Lymnaea natalensis snails.

M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
6137
Figure 2. Effect of the tested enaminone derivatives (at LC25 values) on hatching % of B. alexandrina snails egg masses at the early and late stages.
Table 2. Effect of the enaminone derivatives on the infection rate and
prepatent period of Biomphalaria alexandrina snails, pre-exposed to
LC25 concentrations
that the activity of these derivatives increases within
the increase of the lipophilicity of the molecule against
either B. alexandrina or L. natalensis snails at sublethal
Compound No. of
Infection
Prepatent period (day)
Min Max Mean
and lethal concentrations (LC10, LC25, and LC50).
The relationship between LC10 values against B. alex-
andrina snails and the number of (CH2) units, in the
N-alkyl group in compounds 10a–c, is linear and can
be formulated as: LC10 = 15À4n, where n is the number
of (CH2) units. However, this equation is limited to
n = 0–3, but the mode of lines in Figure 1 shows a fast
change on going from N-methyl to N-ethyl derivatives
and smaller differences with further alkyl chain
elongation.
shedding rate (%)
snailsa
8a
9a
15
18
12
14
21
68.19
81.82
54.54
63.64
95.45
32
32
32
40
28
60
46
66
46
30
46 19.8b
39 9.9b
49 24.0c
43 4.2c
29 1.4
10b
10c
Control
a Number exposed per test = 22 snails.
b Normal distribution statistical significant P < 0.01.
c Normal distribution statistical significant P < 0.001.
Figure 2 represents the hatchability of B. alexandrina
snailsꢀ egg masses exposed to the sublethal concentration
LC25 of compounds 8a, 9a, 10b, and 10c. The figure
indicates that the tested compounds reduced the hatch-
ing percentage and their effect is extended to the aged
eggs. Even if hatchability increases on late stage by ca.
7–20%, it is obvious that the values are still lesser than
control value by ca. 24–40% (Fig. 2). Interestingly, it
was found that LC50 concentrations of the cited four
compounds caused a maximum effect on hatching
percentage (0–5%) at both early and late stages after
exposure for 24 h. These results showed that these com-
pounds, in particular compound 9a, can be considered
for excellent control of generation of snails at lethal
concentration.
Comparison of the prepatent period of S. mansoni in the
B. alexandrina snails exposed to LC25 concentrations of
compounds 8a, 9a, 10b, and 10c with the control value
can indicate their strong effect. Table 2 shows that the
exposure to the tested compounds extended the mean
prepatent period to 39–49 days, while the control value
is only 29 days. Normal distribution patterns were esti-
mated and are statistically significant at P < 0.01 for
compounds 8a and 9a and P < 0.001 for compounds
10b and 10c (Table 2).
2.3. Larvicidal assays
The larvicidal activity of compounds 8a, 9a, 10a, 10b,
and 10c was carried out against the free larval stages
of S. mansoni: miracidia and cercariae. The miracidal
activity is presented in Table 3, which indicated very
high efficiency of the tested compounds on using their
sublethal or lethal concentrations LC10, LC25, and
LC50. Compound 9a caused 100% mortality at concen-
tration of 7.9 ppm in 65 min, while compound 10c
showed the same activity at 6.11 ppm in 55 min. It is
notable that 100% mortality took place on exposure to
The infection rate of B. alexandrina snails treated with
S. mansoni miracidia was studied in both test and con-
trol aquaria. In test aquaria, the snails were exposed
to the sublethal concentration (LC25) of the tested com-
pounds 8a, 9a, 10b, and 10c. It was found that com-
pound 10b is the most effective as it reduced the
infection rate to 54.54%, a result that is about 40% less
than control value (Table 2).

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Table 3. Time required for 100% mortality of Schistosoma mansoni
miracidia and cercariae exposed to sub-lethal and lethal concentrations
of the enaminone derivatives
the lipophilicity of the molecule. The potent mollusci-
cides showed strong effect on hatchability of B. alex-
andrina eggs at different stages. In addition, the
infection rate and prepatent period of B. alexandrina
snails were remarkably controlled on exposure to the
tested enaminones. Larvicidal effect of the new com-
pounds against S. mansoni miracidia and cercariae re-
vealed their high efficacy. Examination of the toxicity
of the candidate molluscicides against D. magna
showed the advantages of these new compounds, which
are environmentally safe, possess potent molluscicidal
and larvicidal activities, and are easily prepared. Fur-
ther experiments and studies on the molluscicidal and
cercaricidal action of these new compounds are cur-
rently carried out along with their application in the
field of chemotherapy of schistosomiasis.
Compound
Time of exposure (min)a
Miracidia Cercariae
LC10
LC25
LC50
LC10
LC25
LC50
8a
9a
160
65
60
60
45
55
65
40
55
640
420
720
180
185
300
260
360
65
195
120
240
40
10a
10b
10c
125
145
140
100
45
55
125
25
a Control gives 100% mortality after 24 h.
the tested compounds at LC50 within an hour (Table 3).
Cercaricidal activity is presented in Table 3, which re-
vealed that 100% mortality occurred on exposure to
LC50 concentrations of the tested compounds 8a, 9a,
10a, 10b, and 10c within time range 25–240 min. It can
be recognized from the results that compound 10c
caused 100% mortality of cercariae in only 25 min at
concentration of 15.88 ppm. Time needed for 100%
mortality using LC10 and LC25 concentrations revealed
that lower concentrations would not give satisfactory
results (Table 3).
4. Experimental
Melting points were uncorrected and were determined in
open capillary tubes on a digital Gallen-kamp MFB-595
apparatus. Infrared spectra were recorded on a Perkin-
Elmer 1650 FT-IR spectrophotometer, using samples
1
in KBr pellets. H and 13C NMR spectra were recorded
on Brucker AC200 (200 MHz) or Varian Gemini
(200 MHz, operating at 50 MHz for 13C), using TMS
as internal standard and CDCl3 or DMSO-d6 as sol-
vents. Mass spectra were taken on a Shimadzu GCMS
QP-1000EX instrument by direct inlet technique at
beam energy 70 eV. Elemental microanalyses were per-
formed on a Perkin-Elmer 2400 analyzer. Compounds
3a–d,12 4a–d,11 5a,b,13 and 6a–d14 were obtained accord-
ing to the previously described procedures.
2.4. Toxicity against Daphnia magna
Daphnia is a commonly used model organism in ecotox-
icological studies. Acute toxicity test against D. magna is
useful as an early warning test for monitoring environ-
ment hazardous chemical treatments of water.18 The
known molluscicides such as niclosamide and copper
sulfate showed considerable toxic effect against Daphnia
at their lethal concentrations.18–21 Remarkably, the
present tested molluscicides showed 0% mortality on
D. magna test at all of their sublethal and lethal concen-
trations (LC10, LC25, LC50, and LC90) after 48 h expo-
sure. Only compound 10b revealed 50% mortality of
D. magna at concentration of 100 ppm after 72 h. More-
over, examination of exposure Daphnia to high concen-
trations (300 ppm) of the tested compounds 8a, 9a, and
10c for 48–72 h showed no significant toxicity toward
this organism, while LC50 of copper sulfate caused
30% Daphnia mortality. The results point to the environ-
mental safety of the use of these new synthetic
molluscicides.
4.1. General procedure for the preparation of 3-[(pyraz-
olinylamino)methylene]quinoline-2,4-diones (8a–d)
A mixture of the appropriate aldehydes 6a–d (10 mmol)
and 4-aminoantipyrine (7) (12 mmol) in glacial acetic
acid (30 mL) was heated under reflux for 2 h. Then,
the reaction mixture was left to stand at room tempera-
ture overnight and the resulting crystalline material was
collected by filtration, washed with cold ethanol, and
recrystallized from the proper solvent.
4.1.1. 3-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-
pyrazol-4-ylamino)methylene]-1-methylquinoline-2,4(1H,3H)-
dione (8a). Prepared from the aldehyde 6a (2.03 g) and
amine 7 (2.44 g) and crystallized from acetic acid. Yield
3.49 g (90%); mp 243–244 °C. IR (KBr): mmax 3218,
3. Conclusions
3062, 2945, 1646 (C@O), 1605, 1580, and 1525 cmÀ1
;
1H NMR (200 MHz, DMSO-d6): d 2.21 (s, 3H, 5-
CH3pyrazoline), 3.21 (s, 3H, N–CH3pyrazoline), 3.80 (s,
3H, N–CH3quinoline), 7.18–7.79 (m, 8H, Harom), 8.18 (d,
J = 7 Hz, 1H, 5-H), 8.45 (d, J = 12.9 Hz, 1H, C@CH–
N), 11.25 (b, 1H, N–H); 13C NMR (50 MHz, DMSO-
d6): d 14.7, 33.6, 35.8, 103.3, 112.7, 119.8, 120.9, 123.6,
124.6, 127.4, 128.1, 128.8, 129.2, 132.3, 139.8, 140.9,
145.2, 160.9, 164.8, 182.6; MS: m/z (I%) 388 (M+, 29),
189 (100). Anal. Calcd for C22H20N4O3 (388.43): C,
68.03; H, 5.19; N, 14.42. Found: C, 67.94; H, 5.15; N,
14.43.
The present study deals with the synthesis of a novel
family of potential molluscicides, in which their prepa-
ration is convenient and their yields are satisfactory.
The synthesis of a series of enaminones derived from
the readily available 4-hydroxy-, 3-acetyl-4-hydroxy-,
and
4-hydroxy-3-(5-oxopyrazolinyl)quinolin-2(1H)-
ones was described. The new compounds showed po-
tent activities against B. alexandrina and L. natalensis
snails. The structure–activity relationship revealed that
molluscicidal activity of 1-alkyl-3-(dimethylamino-
propenoyl)-4-hydroxyquinolinones is correlated with

M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
6139
4.1.2. 3-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-
pyrazol-4-ylamino)methylene]-1-ethylquinoline-2,4(1H,-
3H)-dione (8b). Prepared from the aldehyde 6b (2.17 g)
and amine 7 (2.44 g) and crystallized from ethanol.
Yield 3.69 g (92%); mp 168–169 °C. IR (KBr): mmax
3208, 3073, 2949, 2862, 1643 (C@O), 1621, 1603, 1574,
(83%); mp 274–275 °C. IR (KBr): mmax 3240, 3171,
3067, 2946, 2884, 1660 (C@O), 1632 (C@O), 1618,
1602, 1563, and 1505 cmÀ1
;
1H NMR (200 MHz,
DMSO-d6): d 3.76 (s, 3H, N–CH3), 6.69–7.63 (m, 6H,
Harom), 8.12 (d, J = 8 Hz, 1H, 2-Hpyridine), 8.18 (d,
J = 7 Hz, 1H, 5-Hquinolinone), 8.49 (d, J = 12.6 Hz, 1H,
C@CH–N), 11.51 (b, 1H, N–H); 13C NMR (50 MHz,
DMSO-d6): d 34.5, 108.3, 112.7, 116.6, 120.8, 125.2,
127.6, 129.8, 134.1, 137.8, 147.1, 155.4, 162.8, 163.6,
187.5; MS: m/z (I%) 279 (M+, 36), 186 (100). Anal.
Calcd for C16H13N3O2 (279.30): C, 68.81; H, 4.69; N,
15.04. Found: C, 68.62; H, 4.55; N, 14.84.
1
and 1517 cmÀ1; H NMR (200 MHz, CDCl3): d 1.32
(t, 3H, N–CH2CH3), 2.23 (s, 3H, 5-CH3pyrazoline), 3.19
(s, 3H, N–CH3pyrazoline), 3.52 (q, 2H, N–CH2CH3),
7.15–7.81 (m, 8H, Harom), 8.17 (d, J = 6.8 Hz, 1H,
5-H), 8.43 (d, J = 12.8 Hz, 1H, C@CH–N), 11.65 (b,
1H, N–H); MS: m/z (I%) 402 (M+, 32), 202 (100). Anal.
Calcd for C23H22N4O3 (402.46): C, 68.64; H, 5.51; N,
13.92. Found: C, 68.56; H, 5.55; N, 13.84.
4.2.2. 1-Methyl-3-[(3-pyridylamino)methylene]quinoline-
2,4(1H,3H)-dione (9b). Prepared from the compound
3a (1.75 g), 3-aminopyridine (0.94 g), and DMF-DMA
(1.4 mL) and crystallized from dioxane. Yield 2.32 g
(83%); mp 266–268 °C. IR (KBr): mmax 3225, 3168,
3045, 2949, 2831, and 1658 (C@O), 1631 (C@O), 1622,
4.1.3. 1-Butyl-3-[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihy-
dro-1H-pyrazol-4-ylamino)-methylene]quinoline-2,4(1H,-
3H)-dione (8c). Prepared from the aldehyde 6c (2.45 g)
and amine 7 (2.44 g) and crystallized from methanol.
Yield 3.48 g (81%); mp 146–148 °C. IR (KBr): mmax
3178, 3067, 2927, 2908, 2843, 1641 (C@O), 1622,
1605, 1586, and 1504 cmÀ1
;
1H NMR (200 MHz,
DMSO-d6): d 3.69 (s, 3H, N–CH3), 6.89–7.65 (m, 5H,
Harom), 7.94 (d, J = 8 Hz, 1H, 6-Hpyridine), 8.15 (s, 1H,
2-Hpyridine), 8.18 (d, J = 6.8 Hz, 1H, 5-Hquinolinone),
8.41 (d, J = 12.4 Hz, 1H, C@CH–N), 11.78 (b, 1H, N–
H); MS: m/z (I%) 279 (M+, 54), 186 (100). Anal. Calcd
for C16H13N3O2 (279.30): C, 68.81; H, 4.69; N, 15.04.
Found: C, 68.70; H, 4.62; N, 14.88.
1602, 1571, and 1525 cmÀ1
;
1H NMR (200 MHz,
CDCl3): d 0.97 (t, 3H, N–(CH2)3CH3), 1.30 (m, 4H,
N–CH2(CH2)2CH3), 2.22 (s, 3H, 5-CH3pyrazoline), 3.27
(s, 3H, N–CH3pyrazoline), 3.82 (t, 2H, N– CH2(CH2)2
CH3), 7.12–7.68 (m, 8H, Harom), 8.09 (d, J = 7 Hz,
1H, 5-H), 8.58 (d, J = 12.4 Hz, 1H, C@CH–N), 12.05
(b, 1H, N–H); MS: m/z (I%) 430 (M+, 28), 186 (100).
Anal. Calcd for C25H26N4O3 (430.51): C, 69.75; H,
6.09; N, 13.01. Found: C, 69.73; H, 5.96; N, 12.95.
4.2.3. 1-Methyl-3-[(2-pyrimidylamino)methylene]quino-
line-2,4(1H,3H)-dione (9c). Prepared from the com-
pound 3a (1.75 g), 2-aminopyrimidine (0.95 g), and
DMF-DMA (1.4 mL) and crystallized from NMP. Yield
2.41 g (86%); mp 287–288 °C. IR (KBr): mmax 3246,
3170, 3047, 2945, 2862, 1649 (C@O), 1630 (C@O),
4.1.4. 3-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-
pyrazol-4-ylamino)methylene]-1-phenylquinoline-2,4(1H,-
3H)-dione (8d). Prepared from the aldehyde 6d (2.65 g)
and amine 7 (2.44 g) and crystallized from DMF. Yield
3.80 g (84%); mp 269–270 °C. IR (KBr): mmax 3208,
3073, 2949, 2862, 1643 (C@O), 1621, 1603, 1574, and
1
1621, 1600, 1582, and 1506 cmÀ1; H NMR (200 MHz,
DMSO-d6): d 3.64 (s, 3H, N–CH3), 7.12–7.69 (m, 4H,
Harom), 7.89–7.96 (m, 2H, Harom), 8.18 (d, J = 8 Hz,
1H, 5-Hquinolinone), 8.61 (d, J = 12.4 Hz, 1H, C@CH–
N), 12.18 (b, 1H, N–H). Anal. Calcd for C15H12N4O2
(280.29): C, 64.28; H, 4.32; N, 19.99. Found: C, 64.15;
H, 4.30; N, 20.01.
1
1517 cmÀ1; H NMR (200 MHz, DMSO-d6): d 2.22 (s,
3H, 5-CH3pyrazoline), 3.24 (s, 3H, N–CH3pyrazoline),
7.12–7.83 (m, 13H, Harom), 8.09 (d, J = 6.8 Hz, 1H, 5-
H), 8.55 (d, J = 12.7 Hz, 1H, C@CH–N), 11.46 (b, 1H,
N–H); MS: m/z (I%) 450 (M+, 26), 77 (100). Anal. Calcd
for C27H22N4O3 (450.50): C, 71.99; H, 4.92; N, 12.44.
Found: C, 71.85; H, 4.78; N, 12.32.
4.2.4.
1-Ethyl-3-[(2-pyridylamino)methylene]quinoline-
2,4(1H,3H)-dione (9d). Prepared from the compound
3b (1.89 g), 2-aminopyridine (0.94 g), and DMF-DMA
(1.4 mL) and crystallized from ethanol. Yield 2.37 g
(81%); mp 160–162 °C. IR (KBr): mmax 3172, 3046,
2980, 2822, 2600, 1644–1630 (C@O), 1610, and
4.2. General procedure for the preparation of 1-alkyl-3-
[(pyridyl or pyrimidyl-amino)methylene]quinoline-2,4-diones
(9a–f)
1595 cmÀ1 1H NMR (200 MHz, CDCl3): d 1.37 (t,
;
To a solution of the appropriate hydroxyquinolinones
3a–d (10 mmol) in boiling toluene (50 mL) containing
DMF-DMA (10 mmol), 2- or 3-aminopyridines or 2-py-
rimidine (10 mmol) dissolved in hot toluene (25 mL)
was added dropwise. After complete addition, the reac-
tion mixture was heated at 110 °C for 2 h and then the
excess solvent was evaporated in vacuum. The residual
material was triturated with diethyl ether (25 mL), fil-
tered off, and crystallized from the proper solvent.
3H, N–CH2CH3), 3.69 (q, 2H, N–CH2CH3), 6.82–7.75
(m, 6H, Harom), 8.05 (d, J = 8 Hz, 1H, 2-Hpyridine), 8.12
(d, J = 7 Hz, 1H, 5-Hquinolinone), 8.48 (d, J = 12.5 Hz,
1H, C@CH–N), 12.24 (b, 1H, N–H); MS: m/z (I%)
293 (M+, 26), 201 (100). Anal. Calcd for C17H15N3O2
(293.33): C, 69.61; H, 5.51; N, 14.33. Found: C, 69.50;
H, 5.43; N, 14.08.
4.2.5.
1-Ethyl-3-[(3-pyridylamino)methylene]quinoline-
2,4(1H,3H)-dione (9e). Prepared from the compound
3b (1.89 g), 3-aminopyridine (0.94 g), and DMF-DMA
(1.4 mL) and crystallized from ethanol. Yield 2.49 g
(85%); mp 152–153 °C. IR (KBr): mmax 3187, 2981,
2843, 1651 (C@O), 1637 (C@O), 1612, 1600, and
4.2.1. 1-Methyl-3-[(2-pyridylamino)methylene]quinoline-
2,4(1H,3H)-dione (9a). Prepared from the compound
3a (1.75 g), 2-aminopyridine (0.94 g), and DMF-DMA
(1.4 mL) and crystallized from DMF. Yield 2.32 g

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M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
1
1576 cmÀ1; H NMR (200 MHz, CDCl3): d 1.34 (t, 3H,
N–CH2CH3), 3.53 (q, 2H, N–CH2CH3), 6.97–7.81 (m,
5H, Harom), 8.05–8.12 (m, 3H, Harom), 8.40 (d,
J = 12.7 Hz, 1H, C@CH–N), 12.14 (b, 1H, N–H). Anal.
Calcd for C17H15N3O2 (293.33): C, 69.61; H, 5.51; N,
14.33. Found: C, 69.46; H, 5.37; N, 14.22.
4.3.3. 1-Butyl-3-[2E-3-(dimethylamino)prop-2-enoyl]-4-
hydroxyquinolin-2(1H)-one (10c). Prepared from the acet-
ylquinolinone 4c (2.59 g) and DMF-DMA (1.4 mL) and
crystallized from benzene. Yield 2.54 g (81%); mp 126–
127 °C. IR (KBr): mmax 3131, 3080, 2956, 2924, 2860,
1642 (C@O), 1622, 1526, and 1498 cmÀ1 1H NMR
;
(200 MHz, CDCl3): d 0.96 (t, 3H, N-(CH2)3CH3), 1.31
(m, 4H, N–CH2(CH2)2CH3), 3.02 (s, 3H, N(CH3)2),
3.21 (s, 3H, N(CH3)2), 3.87 (t, 2H, N- CH2(CH2)2CH3),
7.08 (d, J = 13.5 Hz, 1H, COCH@CH–N), 7.21–7.32
(m, 2H, Harom), 7.59 (t, 1H, 7-Hquinolinone), 8.09 (d,
J = 13.5 Hz, 1H, COCH@CH–N), 8.22 (d, J = 8 Hz,
1H, 5-Hquinolinone); MS: m/z (I%) 314 (M+, 28), 270
(100). Anal. Calcd for C18H22N2O3 (314.39): C, 68.77;
H, 7.05; N, 8.91. Found: C, 68.68; H, 6.94; N, 8.56.
4.2.6. 1-Ethyl-3-[(2-pyrimidylamino)methylene]quinoline-
2,4(1H,3H)-dione (9f). Prepared from the compound 3b
(1.89 g), 2-aminopyrimidine (0.95 g), and DMF-DMA
(1.4 mL) and crystallized from ethanol. Yield 2.35 g
(80%); mp 145–147 °C. IR (KBr): mmax 3183, 3076,
2962, 2823, 1645 (C@O), 1623, 1601, 1572, and
1508 cmÀ1 1H NMR (200 MHz, CDCl3): d 1.36 (t,
;
3H, N–CH2CH 3), 3.52 (q, 2H, N–CH2CH3), 7.14–
7.68 (m, 4H, Harom), 7.96–8.14 (m, 3H, Harom), 8.43
(d, J = 12.6 Hz, 1H, C@CH–N), 12.31 (b, 1H, N–H).
Anal. Calcd for C16H14N4O2 (294.34): C, 65.30; H,
4.79; N, 19.04. Found: C, 65.08; H, 4.54; N, 18.72.
4.3.4. 3-[2E-3-(Dimethylamino)prop-2-enoyl]-4-hydroxy-
1-phenylquinolin-2(1H)-one (10d). Prepared from the acet-
ylquinolinone 4d (2.79 g) and DMF-DMA (1.4 mL) and
crystallized from DMF. Yield 3.13 g (94 %); mp 244–
245 °C. IR (KBr): mmax 3173, 3056, 2928, 2805, 1645
4.3. General procedure for the preparation of 3-[3-(di-
methylamino)propenoyl]quinolinones (10a–d)
(C@O), 1603, 1525, and 1492 cmÀ1
;
1H NMR
(200 MHz, CDCl3): d 3.05 (s, 3H, N(CH3)2), 3.19 (s, 3H,
N(CH3)2), 6.62 (d, J = 14.2 Hz, 1H, COCH@CH–N),
7.12–7.78 (m, 8H, Harom), 8.09 (d, J = 14.1 Hz, 1H,
COCH@CH–N), 8.18 (d, J = 8 Hz, 1H, 5-Hquinolinone).
Anal. Calcd for C20H18N2O3 (334.38): C, 71.84; H, 5.43;
N, 8.38. Found: C, 71.52; H, 5.25; N, 8.33.
To a solution of the acetylquinolinones 4a–d (10 mmol),
in dry toluene (50 mL), DMF-DMA (10 mmol) was
added and then the reaction mixture was heated under
reflux for 2 h. The excess solvent was evaporated in vac-
uum and the residual material was triturated with petro-
leum ether (60–80 °C; 25 mL), filtered off, and
crystallized from the proper solvent.
4.4. General procedure for the preparation of 3-[3-(pyrazo-
linylamino)propenoyl]-quinolinones (11a–d)
4.3.1. 3-[2E-3-(Dimethylamino)prop-2-enoyl]-4-hydroxy-
1-methylquinolin-2(1H)-one (10a). Prepared from the
acetylquinolinone 4a (2.17 g) and DMF-DMA (1.4 mL)
and crystallized from methanol. Yield 2.39 g (88%); mp
178–179 °C. IR (KBr): mmax 3075, 2921, 2860, 1660
A mixture of the appropriate enaminones 10a–d
(5 mmol) and amine 7 (5 mmol), in glacial acetic acid
(20 mL), was heated on a water bath under reflux for
1 h. The reaction mixture was left to cool and poured
onto crushed ice to give solid deposits. The product
was filtered off and crystallized from the proper solvent.
(C@O), 1649 (C@O), 1620, 1600, 1567, and 1504 cmÀ1
;
1H NMR (200 MHz, CDCl3): d 3.02 (s, 3H, N(CH3)2),
3.30 (s, 3H, N(CH3)2), 3.51 (s, 3H, N–CH3), 7.05 (d,
J = 15.7 Hz, 1H, COCH@CH–N), 7.21–7.66 (m, 3H,
Harom), 8.08 (d, J = 8 Hz, 1H, 5-Hquinolinone), 8.18 (d,
J = 15.6 Hz, 1H, COCH@CH–N); 13C NMR (50 MHz,
CDCl3): d 30.21, 38.82, 39.01, 93.05, 115.44, 118.21,
122.35, 125.33, 128.82, 134.74, 141.32, 157.45, 161.05,
177.08, 187.39; MS: m/z (I%) 272 (M+, 36), 228 (100).
Anal. Calcd for C15H16N2O3 (272.31): C, 66.16; H, 5.92;
N, 10.29. Found: C, 65.94; H, 5.76; N, 10.20.
4.4.1. 3-{[2E-3-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihy-
dro-1H-pyrazol-4-yl)amino]prop-2-enoyl}-4-hydroxy-1-
methylquinolin-2(1H)-one (11a). Prepared from the
enaminone 10a (1.36 g) and amine 7 (1.02 g) and crystal-
lized from DMF. Yield 1.87 g (87%); mp 234–235 °C. IR
(KBr): mmax 3211, 3056, 2921, 2883, 1662 (C@O), 1645
(C@O), 1618, 1601, and 1575 cmÀ1
;
1H NMR
(200 MHz, DMSO-d6): d 2.23 (s, 3H, 5-CH3pyrazoline),
3.15 (s, 3H, N–CH3pyrazoline), 3.71 (s, 3H, N–
CH3quinolinone), 6.68 (d, J = 12.8 Hz, 1H, COCH@CH–
N), 7.12–7.66 (m, 8H, Harom), 8.21 (d, J = 8 Hz, 1H,
5-Hquinolinone), 8.65 (d, J = 13 Hz, 1H, COCH@CH–
N), 11.33 (b, 1H, N–H); 13C NMR (50 MHz, DMSO-
d6): d 12.8, 34.6, 35.8, 102.7, 109.2, 110.3, 119.6, 120.4,
124.2, 124.6, 126.0, 127.2, 128.2, 128.8, 129.3, 138.8,
139.1, 140.6, 161.7, 162.5, 173.7, 187.4; MS: m/z (I%)
430 (M+, 32), 199 (100). Anal. Calcd for C24H22N4O4
(430.47): C, 66.97; H, 5.15; N, 13.02. Found: C, 66.83;
H, 5.26; N, 12.88.
4.3.2. 3-[2E-3-(Dimethylamino)prop-2-enoyl]-1-ethyl-4-
hydroxyquinolin-2(1H)-one (10b). Prepared from the
acetylquinolinone 4b (2.31 g) and DMF-DMA
(1.4 mL) and crystallized from ethanol. Yield 2.63 g
(92 %); mp 148–149 °C. IR (KBr): mmax 3124, 3038,
2974, 2928, 1643 (C@O), 1606, 1525, and 1493 cmÀ1
;
1H NMR (200 MHz, CDCl3): d 1.35 (t, 3H, N–
CH2CH3), 3.09 (s, 3H, N(CH3)2), 3.25 (s, 3H,
N(CH3)2), 4.27 (q, 2H, N–CH2CH3), 7.12 (d,
J = 12.8 Hz, 1H, COCH@CH–N), 7.18–7.36 (m, 2H,
Harom), 7.60 (t, 1H, 7-Hquinolinone), 8.08 (d,
J = 12.8 Hz, 1H, COCH@CH–N), 8.25 (d, J = 7 Hz,
1H, 5-Hquinolinone); MS: m/z (I%) 286 (M+, 38), 242
(100). Anal. Calcd for C16H18N2O3 (286.33): C, 67.12;
H, 6.34; N, 9.78. Found: C, 66.85; H, 6.21; N, 9.81.
4.4.2. 3-{[2E-3-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-
1H-pyrazol-4-yl)amino]prop-2-enoyl}-1-ethyl-4-hydroxy-
quinolin-2(1H)-one (11b). Prepared from the enaminone
10b (1.43 g) and amine 7 (1.02 g) and crystallized from

M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
6141
dioxane. Yield 1.69 g (76%); mp 191–192 °C. IR (KBr):
mmax 3226, 3174, 3063, 2980, 2675, 1660 (C@O),
3H, N–CH3quinolinone), 7.21–7.32 (m, 3H, 6-Hquinolinome
8-Hquinolinone COCH@CH–N), 7.64 (t, 1H,
7-Hquinolinone), 8.14 (d, J = 16 Hz, 1H, COCH@CH–
N), 8.28 (d, J = 8 Hz, 1H, 5-Hquinolinone); MS: m/z (I%)
312 (M+, 32), 69 (100). Anal. Calcd for C18H20N2O3
(312.37): C, 69.21; H, 6.45; N, 8.97. Found: C, 69.08;
H, 6.41; N, 8.78.
+
+
1639 (C@O), 1617, 1599, and 1572 cmÀ1
;
1H NMR
1.37 (t, 3H, N–CH2
(200 MHz, DMSO-d6):
d
CH3), 2.18 (s, 3H, 5-CH3pyrazoline), 3.26 (s, 3H, N–
CH3pyrazoline), 4.09 (q, 2H, N–CH2CH3), 6.64 (d,
J = 12.5 Hz, 1H, COCH@CH–N), 7.11–7.63 (m, 8H,
Harom), 8.23 (d, J = 8 Hz, 1H, 5-Hquinolinone), 8.49 (d,
J = 12.5 Hz, 1H, COCH@CH–N), 11.28 (b, 1H, N–
H). Anal. Calcd for C25H24N4O4 (444.49): C, 67.56;
H, 5.44; N, 12.60. Found: C, 67.37; H, 5.29; N, 12.41.
4.5.2. 4-Hydroxy-1-methyl-3-[2E-3-(4-morpholinyl)prop-
2-enoyl]quinolin-2(1H)-one (13b). Prepared from the
enaminone 10a (1.36 g) and morpholine (0.5 mL) and
crystallized from ethanol. Yield 1.16 g (74%); mp 231–
232 °C. IR (KBr): mmax 3076, 2944, 2926, 2845, 1646
4.4.3. 1-Butyl-3-{[2E-3-(1,5-dimethyl-3-oxo-2-phenyl-2,3-
dihydro-1H-pyrazol-4-yl)amino]prop-2-enoyl}-4-hydroxy-
quinolin-2(1H)-one (11c). Prepared from the enaminone
10c (1.57 g) and amine 7 (1.02 g) and crystallized
from ethanol. Yield 1.70 g (72%); mp 149–150 °C. IR
(KBr): mmax 3182, 3071, 2992, 2945, 2886, 2676, 1658
(C@O), 1606, 1541, and 1487 cmÀ1
;
1H NMR
(200 MHz, CDCl3): d 3.55 (m, 4H, N(CH2)2morpholine),
3.68 (s, 3H, N–CH3quinolinone), 4.26 (m, 4H, O(CH2)2 mor-
pholine), 7.14–7.34 (m, 3H, 6-Hquinolinome + 8-Hquinolinone
+
COCH@CH–N), 7.66 (t, 1H, 7-Hquinolinone), 8.18 (d,
J = 16 Hz, 1H, COCH@CH–N), 8.28 (d, J = 7 Hz, 1H,
5-Hquinolinone). Anal. Calcd for C17H18N2O4 (314.34): C,
64.96; H, 5.77; N, 8.91. Found: C, 64.80; H, 5.56; N, 8.83.
(C@O), 1641 (C@O), 1622, 1601, 1576, and 1555 cmÀ1
;
1H NMR (200 MHz, CDCl3): d 0.95 (t, 3H, N–
(CH2)3CH3), 1.31 (m, 4H, N–CH2(CH2)2CH3), 2.20 (s,
3H, 5-CH3pyrazoline), 3.28 (s, 3H, N–CH3pyrazoline), 3.81
(t, 2H, N–CH2(CH2)2CH3), 6.87 (d, J = 13.4 Hz, 1H,
COCH@CH–N), 7.16–7.78 (m, 8H, Harom), 8.09 (d,
J = 7 Hz, 1H, 5-Hquinolinone), 8.46 (d, J = 13.3 Hz, 1H,
COCH@CH–N), 11.92 (b, 1H, N–H). Anal. Calcd for
C27H28N4O4 (472.55): C, 68.63; H, 5.97; N, 11.86. Found:
C, 68.62; H, 5.92; N, 11.68.
4.5.3. 1-Ethyl-4-hydroxy-3-[2E-3-(1-piperidyl)prop-2-en-
oyl]quinolin-2(1H)-one (13c). Prepared from the enami-
none 10b (1.43 g) and piperidine (0.5 mL) and
crystallized from ethanol. Yield 1.22 g (75%); mp 168–
169 °C. IR (KBr): mmax 3086, 2952, 2883, 1651 (C@O),
1638 (C@O), 1602, 1544, and 1505 cmÀ1 1H NMR
;
(200 MHz, CDCl3):
d 1.39 (t, 3H, N–CH2CH3),
4.4.4. 3-{[2E-3-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihy-
dro-1H -pyrazol-4-yl)amino]prop-2-enoyl}-4-hydroxy-1-
phenylquinolin-2(1H)-one (11d). Prepared from the
enaminone 10d (1.67 g) and amine 7 (1.02 g) and crystal-
lized from DMF. Yield 2 g (81%); mp 288–289 °C. IR
(KBr): mmax 3064, 2985, 2672, 1662 (C@O), 1645
1.69–1.80 (m, 6H, (CH2)3piperidine), 3.55 (m, 4H,
N(CH2)2piperidine), 3.82 (q, 2H, N–CH2CH3), 7.18–7.36
(m, 3H, 6-Hquinolinome + 8-Hquinolinone + COCH@CH–
N), 7.64 (t, 1H, 7-Hquinolinone), 8.13 (d, J = 14.6 Hz,
1H, COCH@CH–N), 8.24 (d, J = 7 Hz, 1H, 5-Hquinoli-
none). Anal. Calcd for C19H22N2O3 (326.40): C, 69.92;
H, 6.79; N, 8.58. Found: C, 69.73; H, 6.54; N, 8.48.
(C@O), 1620, 1606, 1570, and 1556 cmÀ1 1H NMR
;
(200 MHz, DMSO-d6): 2.22 (s, 3H, 5-CH3pyrazoline),
3.38 (s, 3H, N–CH3pyrazoline), 6.57 (d, J = 14.2 Hz, 1H,
COCH@CH–N), 6.98–7.82 (m, 13H, Harom), 8.12 (d,
J = 8 Hz, 1H, 5-Hquinolinone), 8.38 (d, J = 14.1 Hz, 1H,
COCH@CH–N), 12.08 (b, 1H, N–H). Anal. Calcd for
C29H24N4O4 (492.54): C, 70.72; H, 4.91; N, 11.38.
Found: C, 70.51; H, 5.03; N, 11.20.
4.5.4. 1-Ethyl-4-hydroxy-3-[2E-3-(4-morpholinyl)prop-2-
enoyl]quinolin-2(1H)-one (13d). Prepared from the
enaminone 10b (1.43 g) and morpholine (0.5 mL) and
crystallized from dioxane. Yield 1.18 g (72%); mp 177–
178 °C. IR (KBr): mmax 3072, 2981, 2934, 2844, 1652–
1640 (C@O), 1607, 1556, and 1501 cmÀ1 1H NMR
;
(200 MHz, CDCl3): d 1.38 (t, 3H, N–CH2CH3), 3.52
(m, 4H, N(CH2)2morpholine), 4.03 (q, 2H, N–CH2CH3),
4.25 (m, 4H, O(CH2)2morpholine), 7.22–7.37 (m, 3H, 6-
Hquinolinome + 8-Hquinolinone + COCH@CH–N), 7.61 (t,
1H, 7-Hquinolinone), 8.19 (d, J = 16 Hz, 1H,
COCH@CH–N), 8.26 (d, J = 7 Hz, 1H, 5-Hquinolinone).
Anal. Calcd for C18H20N2O4 (328.37): C, 65.84; H,
6.14; N, 8.53. Found: C, 65.64; H, 6.03; N, 8.39.
4.5. General procedure for the preparation of 3-[3-(1-
piperidyl or 4-morpholinyl)-propenoyl]quinolinones (13a–d)
Equimolar amounts (5 mmol) of the enaminones 10a
or 10b and piperidine or morpholine, in dioxane
(25 mL), were heated under reflux for 1 h. The reac-
tion mixture was left to cool and then poured onto
crushed ice to give yellow precipitates. The product
was collected by filtration off and crystallized from
the proper solvent.
4.6. General procedure for the preparation of 3-[4-(di-
methylaminomethylene)pyrazolyl]-quinolinones (14a,b)
4.5.1. 4-Hydroxy-1-methyl-3-[2E-3-(1-piperidyl)prop-2-
enoyl]quinolin-2(1H)-one (13a). Prepared from the
enaminone 10a (1.36 g) and piperidine (0.5 mL) and
crystallized from ethanol. Yield 1.18 g (76%); mp 214–
215 °C. IR (KBr): mmax 3130, 2941, 2917, 2865, 1650
A mixture of the pyrazolinones 5a or 5b (10 mmol) and
DMF-DMA (15 mmol), in p-xylene (50 mL), was heated
under reflux for 2 h. The reaction mixture was left to cool
in an ice bath for a night. The crystalline product so
formed was collected by filtration and washed with petro-
leum ether (40–60 °C; 50 mL). The products were pure en-
ough and used for subsequent reactions without further
purification.
(C@O), 1626 (C@O), 1603, 1545, and 1499 cmÀ1
;
1H NMR (200 MHz, CDCl3): d 1.71–1.80 (m, 6H,
(CH2)3piperidine), 3.52 (m, 4H, N(CH2)2piperidine), 3.64 (s,

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4.6.1. 3-{4-[(Dimethylamino)methylene]-5-oxo-4,5-dihy-
dro-1H-pyrazol-3-yl}-4-hydroxy-1-methylquinolin-2(1H)-
one (14a). Prepared from the pyrazolinone 5a (2.57 g) and
DMF-DMA (2.1 mL). Yield 2.52 g (81%); mp 297–
300 °C. IR (KBr): mmax 3225 (N–H), 3174, 2945, 1662
DMF. Yield 1.42 g (78 %); mp 279–280 °C (lit.,13 yield
68%; mp 279–281 °C).
4.7.4. 1-Ethyl-4-hydroxy-3-{5-oxo-4-[(2-pyridylamino)-
methylene]-4,5-dihydro-1H-pyrazol-3-yl} quinolin-2(1H)-
one (15d). Prepared from compound 14b (1.63 g) and
2-aminopyridine (0.48 g) and crystallized from ethanol.
Yield 1.40 g (75%); mp 226–228 °C. IR (KBr): mmax
3320 (N–H), 3180, 2989, 2846, 1663 (C@O), 1648
1
(C@O), 1642 (C@O), 1620, 1552, and 1476 cmÀ1; H
NMR (200 MHz, DMSO-d6): d 3.05 (s, 3H, N(CH3)2),
3.28 (s, 3H, N(CH3)2), 3.64 (s, 3H, N–CH3), 7.23–7.65
(m, 3H, 6-H + 8-H + 7-H), 8.09 (d, J = 7 Hz, 1H, 5-H),
8.26 (s, 1H, C@CH–N), 11.52 (b, 1H, N–H), 12.61 (b,
1H, O–H); MS: m/z (I%) 312 (M+, 25), 267 (100). Anal.
Calcd for C16H16N4O3 (312.33): C, 61.53; H, 5.16; N,
17.94. Found: C, 61.36; H, 4.92; N, 18.08.
(C@O), 1618, 1607, and 1566 cmÀ1
;
1H NMR
(200 MHz, DMSO-d6): d 1.38 (t, 3H, N–CH2CH3),
3.84 (q, 2H, N–CH2CH3), 6.94–8.05 (m, 8H, Harom),
8.35 (d, J = 12.2 Hz, 1H, C@CH–N), 9.45 (b, 1H,
N–H), 11.86 (b, 1H, N–H), 12.68 (b, 1H, O–H). Anal.
Calcd for C20H17N5O3 (375.39): C, 63.99; H, 4.56; N,
18.66. Found: C, 63.81; H, 4.52; N, 18.40.
4.6.2. 3-{4-[(Dimethylamino)methylene]-5-oxo-4,5-dihy-
dro-1H-pyrazol-3-yl}-1-ethyl-4-hydroxyquinolin-2(1H)-
one (14b). Prepared from the pyrazolinone 5b (2.71 g)
and DMF-DMA (2.1 mL). Yield 2.41 g (74%); mp
264–265 °C. IR (KBr): mmax 3245 (N–H), 3178, 2972,
2861, 1654 (C@O), 1644 (C@O), 1618, 1573, and
4.7.5. 1-Ethyl-4-hydroxy-3-{5-oxo-4-[(3-pyridylamino)-
methylene]-4,5-dihydro-1H-pyrazol-3-yl}quinolin-2(1H)-
one (15e). Prepared from compound 14b (1.63 g) and
3-aminopyridine (0.48 g) and crystallized from acetone.
Yield 1.74 g (93 %); mp 220–221 °C. IR (KBr): mmax
3335 (N–H), 3176, 2978, 2864, 1658 (C@O), 1641
1
1503 cmÀ1; H NMR (200 MHz, DMSO-d6): d 1.40 (t,
3H, N–CH2CH3), 3.03 (s, 3H, N(CH3)2), 3.22 (s, 3H,
N(CH3)2), 3.86 (q, 2H, N–CH2CH3), 7.28–7.62 (m,
3H, 6-H + 8-H + 7-H), 8.13 (d, J = 7 Hz, 1H, 5-H),
8.25 (s, 1H, C@CH–N), 11.84 (b, 1H, N–H), 12.66 (b,
1H, O–H); MS: m/z (I %) 326 (M+, 44), 281 (100). Anal.
Calcd for C17H18N4O3 (326.36): C, 62.57; H, 5.56; N,
17.17. Found: C, 62.30; H, 5.51; N, 16.92.
(C@O), 1621, 1608, and 1562 cmÀ1
;
1H NMR
(200 MHz, DMSO-d6): d 1.42 (t, 3H, N–CH2CH3),
3.87 (q, 2H, N–CH2CH3), 6.88–8.08 (m, 8H, Harom),
8.41 (d, J = 12.4 Hz, 1H, C@CH–N), 9.28 (b, 1H,
N–H), 11.60 (b, 1H, N–H), 12.45 (b, 1H, O–H). Anal.
Calcd for C20H17N5O3 (375.39): C, 63.99; H, 4.56; N,
18.66. Found: C, 63.78; H, 4.43; N, 18.47.
4.7. General procedure for the preparation of 3-[4-(hetaryl-
aminomethylene)pyrazolyl]-quinolinones (15a–f)
4.7.6. 1-Ethyl-4-hydroxy-3-{5-oxo-4-[(2-pyrimidylamino)-
methylene]-4,5-dihydro-1H-pyrazol-3-yl}quinolin-2(1H)-
one (15f). Prepared from compound 14b (1.63 g) and
2-aminopyrimidine (0.49 g) and crystallized from DMF.
Yield 1.38 g (73%); mp 256–257 °C. IR (KBr): mmax 3324
(N–H), 3208, 2943, 2852, 1661 (C@O), 1638 (C@O),
A mixture of compound 14a or 14b (5 mmol) and 2- or
3-aminopyridine or 2-aminopyrimidine (5 mmol), in gla-
cial acetic acid (25 mL), was heated under reflux for 1 h.
The reaction mixture was left to cool to room tempera-
ture and the precipitate so formed was collected by
filtration and crystallized from the suitable solvent.
1616, 1605, and 1556 cmÀ1
;
1H NMR (200 MHz,
DMSO-d6): d 1.41 (t, 3H, N–CH2CH3), 3.86 (q, 2H,
N–CH2CH3), 7.12–8.08 (m, 7H, Harom), 8.40 (d,
J = 12.6 Hz, 1H, C@CH–N), 9.84 (b, 1H, N–H), 12.08
(b, 1H, N–H), 13.21 (b, 1H, O–H). Anal. Calcd for
C19H16N6O3 (376.38): C, 60.63; H, 4.28; N, 22.23. Found:
C, 60.45; H, 4.31; N, 22.05.
4.7.1. 4-Hydroxy-1-methyl-3-{5-oxo-4-[(2-pyridylamino)-
methylene]-4,5-dihydro-1H-pyrazol-3-yl} quinolin-2(1H)-
one (15a). Prepared from compound 14a (1.56 g) and
2-aminopyridine (0.48 g) and crystallized from ethanol.
13
Yield 1.53 g (85%); mp 237–238 °C (lit.,
mp 235–236 °C).
yield 76%;
4.8. General procedure for the preparation of 3-[4-(pyraz-
olylaminomethylene)pyrazolyl]-quinolinones (16a,b)
4.7.2. 4-Hydroxy-1-methyl-3-{5-oxo-4-[(3-pyridylamino)-
methylene]-4,5-dihydro- 1H-pyrazol-3-yl}quinolin-2(1H)-
one (15b). Prepared from compound 14a (1.56 g) and
3-aminopyridine (0.48 g) and crystallized from acetone.
Yield 1.45 g (80%); mp 242–244 °C. IR (KBr): mmax 3380
(N–H), 3135, 2992, 2883, 1666 (C@O), 1645 (C@O),
A mixture of equimolar amounts (5 mmol) of the pyraz-
olinone 5a or 5b, triethyl orthoformate, and amine 7, in
ethylene glycol (20 mL), was heated under short air
condenser at 110 °C for 30 min. Then, the reaction
temperature was raised gradually to 190 °C during 1 h.
The reaction mixture was left to cool to room tempera-
ture and triturated with cold methanol (20 mL). The
solid deposits so obtained was collected by filtration
and crystallized from the suitable solvent.
1
1619, 1611, 1586, and 1545 cmÀ1; H NMR (200 MHz,
DMSO-d6): d 3.64 (s, 3H, N–CH3), 6.98–8.09 (m, 8H,
Harom), 8.31 (d, J = 12.8 Hz, 1H, C@CH–N), 9.28 (b,
1H, N–H), 11.30 (b, 1H, N–H), 12.55 (b, 1H, O–H). Anal.
Calcd for C19H15N5O3 (361.36): C, 63.15; H, 4.18; N,
19.38. Found: C, 63.05; H, 3.95; N, 19.21.
4.8.1. 3-{4-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-
pyrazol-4-ylamino)-methylene]-5-oxo-4,5-dihydro-1H-pyr-
azol-3-yl}-4-hydroxy-1-methylquinolin-2(1H)-one (16a).
Prepared from compound 5a (1.29 g), triethyl orthofor-
mate (0.9 mL), and amine 7 (1.04 g) and crystallized from
4.7.3. 4-Hydroxy-1-methyl-3-{5-oxo-4-[(2-pyrimidylami-
no)methylene]-4,5-dihydro-1H-pyrazol-3-yl}quinolin-2(1H)-
one (15c). Prepared from compound 14a (1.56 g) and
2-aminopyrimidine (0.49 g) and crystallized from

M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
6143
dioxane. Yield 2.16 g (92%); mp 198–199 °C (lit.,13 yield
84%; mp 195–197 °C).
carried out with the LC25 concentrations of the tested
compounds and control group of eggs were maintained
in dechlorinated water. Infection rate and prepatent
period experiments were carried out using four groups
each of 30 snails (4–6 mm shell diameter) maintained
at the LC25 concentrations of each compound for
24 h. From the surviving snails, four groups of 22 snails
per aquarium were exposed to S. mansoni miracidia with
a dose of 10 miracidia/snail for 24 h at room tempera-
ture and ceiling illumination. A control group of 22
snails was exposed to miracidia in the absence of tested
molluscicides.
4.8.2. 3-{4-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-
pyrazol-4-ylamino)-methylene]-5-oxo-4,5-dihydro-1H-pyr-
azol-3-yl}-1-ethyl-4-hydroxyquinolin-2(1H)-one
(16b).
Prepared from compound 5b (1.36 g), triethyl orthofor-
mate (0.9 mL), and amine 7 (1.04 g) and crystallized
from ethanol. Yield 2.15 g (89%); mp 186–187 °C. IR
(KBr): mmax 3331 (N–H), 3212, 3145, 2956, 2847, 1663
(C@O), 1636 (C@O), 1618, 1608, 1572, 1550, and
1
1444 cmÀ1; H NMR (200 MHz, DMSO-d6): d 1.37 (t,
3H, N–CH2CH3), 2.21 (s, 3H, 5-CH3pyrazolone), 3.30 (s,
3H, N–CH3pyrazolone), 3.71 (q, 2H, N–CH2CH3), 7.06–
7.78 (m, 8H, Harom), 8.08 (d, J = 7H, 1H, 5-Hquinolinone),
8.52 (d, J = 12.3 Hz, 1H, C@CH–N), 9.65 (b, 1H, N–H),
10.25 (b, 1H, N–H), 12.88 (b, 1H, O–H). Anal. Calcd for
C26H24N6O4 (484.52): C, 64.45; H, 4.99; N, 17.35.
Found: C, 64.17; H, 4.95; N, 17.22.
4.9.3. Larvicidal activity. Miracidal and cercaricidal ef-
fect of the tested five compounds was examined at
LC10, LC25, and LC50 concentrations. Twenty-five milli-
liters of dechlorinated water containing 100 freshly
hatched miracidia or freshly sheded cercariae was mixed
with 25 mL of double concentrations of the candidate
molluscicide solutions. Fifty milliliters of dechlorinated
water containing 100 freshly hatched miracidia or fresh-
ly sheded cercariae was used as a control. The mortality
was microscopically checked at intervals of 5 min and
the times required for 100% mortality of both S. manso-
ni miracidia and cercariae were recorded.
4.9. Molluscicidal and larvicidal bioassays
4.9.1. Snails source and conditions. Adult laboratory
bred B. alexandrina and S. mansoni miracidia and cerca-
riae were obtained from Schistosoma Biological Supply
Center (SBSC) at Theodor Bilharz Research Institute
(TBRI) to ensure infection-free snails with high suscep-
tibility for infection experiments. Healthy B. alexandrina
(10–12 mm shell diameter) and L. natalensis (10–13 mm
shell height) snails were collected from local irrigation
canals and ponds at Giza and Kalubia and acclimatized
to laboratory conditions for 3 weeks. Groups of 10
experimental snails were then transferred to well-aerated
glass aquaria containing 2 L of dechlorinated water and
kept at 24 1 °C. The snails were fed on boiled or oven-
dried lettuce leaves. Each aquarium was provided with a
polyethylene sheet for ova-position, and the eggs were
counted using a binuclear stereomicroscope. From each
early and late embryonic stage, 100 eggs were used to
study the effect of the molluscicides on egg development
and hatchability.
4.9.4. Toxicity test against Daphnia. The tests were con-
ducted in D. magna following the European Guideline.18
The Daphnia-bioassay-used daphnids were bred in cul-
ture medium imitating natural fresh water. Test plates
with D. magna neonates were incubated for 24–48 h at
24 1 °C in dark. Acute toxicity was assessed by noting
the effects of the tested compounds on the mobility of D.
magna. The neonates were considered immobile if, after
48 h of incubation with the toxicant, they remained set-
tled at the bottom of the test container and did not re-
sume swimming with 15 s observation period. For each
test, 20 healthy neonates were exposed to 50 mL of
LC10, LC25, LC50, and LC90 concentrations of the tested
compounds. Triplicate and control experiments were
carried out for each concentration and the average mor-
tality (immobilization) value was calculated.
4.9.2. Molluscicidal activity. Molluscicidal effect of the
new compounds was evaluated according to WHO pro-
cedure22 with slight modification23 by inclusion of an in-
ert solvent to help in the dissolution of samples. The
compounds were dissolved first in a small amount of
DMF and added to dechlorinated water to obtain
0.1% solution. The bioassay involved immersion of
adult snails in the mixed aqueous solution of the inves-
tigated compounds at final concentration ranging from
5 to 100 ppm for 24 h, at room temperature and under
normal diurnal lighting. Then, the aquaria were decant-
ed and the snails were rinsed twice with dechlorinated
water and offered lettuce leaves as food. The test snails
were then left in water for another 24 h as a recovery
period and examined to assess mortality and computed
to estimate the LC10, LC25, LC50, and LC90 values.24
Snails were considered dead if they remained motionless
and did not respond to the presence of food. In the con-
trol experiments, snails were exposed to 0.1% DMF
without addition of the test molluscicides at the same
experimental conditions. Hatchability experiments were
References and notes
1. WHO, World Health Report, 2004.
2. WHO, TDR/Schistosomiasis, 2002.
3. (a) Abreu, F. C.; Paula, F. S.; Dos Santos, A. F.; SantAna,
´
´
A. E. G.; Almeida, M. V.; Cesar, E. T.; Trindade, M. N.;
Goulart, M. O. F. Bioorg. Med. Chem. 2001, 9, 659; (b)
Lardans, V.; Dissous, C. Parasitol. Today 1998, 14, 413.
4. Clark, T. E.; Appleton, C. C.; Drewes, S. E. J. Ethno-
pharmacol. 1997, 56, 1.
5. Doenhoff, M. J.; Kusel, J. R.; Coles, G. C.; Cioli, D.
Trans. R. Soc. Trop. Med. Hyg. 2002, 96, 465.
6. Whitfield, P. J. Trans. R. Soc. Trop. Med. Hyg. 1996, 90,
596.
7. Vieira, P. C.; Kubo, I. Phytochemistry 1990, 29, 813.
8. Mohamed, E. A.; Ismail, M. M.; Gabr, Y.; Abass, M.
Chem. Pap. 1994, 48, 285.
9. Perret, S.; Whitfield, P. J. Planta Med. 1995, 61, 276.
10. (a) Bosson, J. A.; Rasmussen, M.; Ritchie, E.; Robertson,
A. V.; Taylor, W. C. Aust. J. Chem. 1963, 16, 480; (b)

6144
M. Abass, B. B. Mostafa / Bioorg. Med. Chem. 13 (2005) 6133–6144
Bownan, R. E.; Campbell, A.; Tanner, E. M. J. Chem.
Soc. 1959, 444.
11. Kappe, T.; Aigner, R.; Hohengassner, P.; Stadlbauer, W.
J. Prakt. Chem. 1994, 336, 596.
18. (a) Commission of the European Communities, ‘‘Methods
for Determination of Ecotoxicity’’, Annex V, C.2, Daph-
nia, Acute Toxicity to Daphnia, L 384 A, EEC Directive
92/69/EEC, 1992, pp 172–178; (b) Hernando, M. D.;
Fernandez-Alba, A. R.; Tauler, R.; Barcelo, D. Talanta
2005, 65, 358.
19. Fjallborg, B.; Dave, G. Environ. Int. 2003, 28, 761.
20. De Oliveira-Filho, E. C.; Lopes, R. M.; Paumgartlen, F. J.
R. Chemosphere 2004, 56, 369.
21. (a) Mostafa, B. B.; Abdel Kader, A.; Ragab, F. M. A.; El-
Said, K. M.; Tantawy, A. A.; El Khayat, H. M. M. Egypt.
J. Schistosom. Infect. Endem. Dis. 2003, 25, 77; (b) Abdel-
Kader, A.; Mostafa, B. B.; Ragab, F. M. A.; El-Said, K.
M.; Tantawy, A. A.; El Khayat, H. M. M. Egypt. J.
Schistosom. Infect. Endem. Dis. 2003, 25, 53.
12. Mohamed, E. A. J. Chem. Soc. Pak. 1991, 13, 166.
13. (a) Abass, M.; Othman, E. S. Synth. Commun. 2001, 31,
3361; (b) Ismail, M. M.; Othman, E. S.; Mohamed, H. M.
Chem. Pap. 2005, 59, 117.
14. Tomita, K. J. Pharm. Soc. Jpn. 1951, 71, 1100.
15. (a) Vrijenhoek, R. C.; Graven, M. A. J. Hered. 1992, 83, 255;
(b) Kalbe, M.; Haberl, B.; Haas, W. Parasitol. Res. 1996, 82, 8.
16. (a) Yousif, F.; Ibrahim, A.; El Bardicy, S. N. J. Egypt.
Soc. Parasitol. 1998, 28, 863; (b) Kristensen, T. K.; Yousif,
F.; Raahauge, P. J. Moll. Stud. 1999, 65, 133; (c) Lotfy,
W. M. R.; DeJong, J.; Black, B. S.; Loker, E. S. Mol. Cell.
Probes 2005, 19, 21.
17. (a) Shoeb, H. A.; El-Emam, M. A. Egypt. J. Bilharz. 1975,
2, 295; (b) Rawi, S. M.; El-Gindy, H.; Abd-El-Kader, A.
Ecotoxicol. Environ. Saf. 1996, 35, 261; (c) Abdel Kader,
A.; Sharaf El Din, A. Egypt. J. Schistosom. Infect. Endem.
Dis. 2000, 22, 159.
22. WHO, Reports of the Scientific Working Group on Plant
Molluscicides, TDR/SCH. SWG/4/83.3, Geneva, 1993.
´
23. Dos Santos, A. F.; SantAna, A. E. G. Phytother. Res.
1999, 13, 660.
24. Litchfield, J. T.; Wilcoxson, F. J. Pharm. Exp. Ther. 1949,
96, 99.