Schiff bases of indoline-2,3-dione (isatin) derivatives and nalidixic acid carbohydrazide, synthesis, antitubercular activity and pharmacophoric model building

Article abstract of DOI:10.1016/j.ejmech.2010.07.020

Tuberculosis (TB) remains among the world's great public health challenges. Worldwide resurgence of TB is due to two major problems: the AIDS epidemic, which started in the mid-1980s, and the outbreak of multidrug resistant (MDR) TB. Thus, there is an urgent need for anti-TB drugs with enhanced activity against MDR strains. In recent years, Schiff bases of 1H-indole-2,3-diones are reported to exhibit anti-TB activity. On the other hand, several quinolone antibacterial agents have been examined as inhibitors of TB, as well as other mycobacterial infections. Accordingly, the current work involved design and synthesis of Schiff bases of nalidixic acid carbohydrazide and isatin derivatives (5,6a-f and 7,8a-c). Structures of the synthesized derivatives were confirmed on the bases of spectral methods of analyses. Anti-TB activity of the synthesized derivatives was investigated against four Mycobacterium strains: Mycobacterium intercellulari, Mycobacterium xenopi, Mycobacterium cheleneo and Mycobacterium smegmatis. Modest anti-TB activity was observed within the investigated compounds, however, compound 5f revealed potent anti-TB activity with MIC 0.625 μg/ml, which is 20 times greater than the reference drug isoniazid, INH, (MIC = 12.5 μg/ml). A hypothetical pharmacophore model was built using Molecular Operating Environment (MOE) program and 10 compounds structurally related to the synthesized ones with reported anti-TB activity. The Pharmacophoric model built revealed the necessity of the following pharmacophoric features for anti-TB activity: aromatic center, hydrogen bond acceptor/metal ligator center, hydrogen bond donor center and aromatic center/hydrophobic area. Theses features were consistent with the found anti-TB activity of the tested compounds.

Full text of DOI:10.1016/j.ejmech.2010.07.020

European Journal of Medicinal Chemistry 45 (2010) 4578e4586
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Schiff bases of indoline-2,3-dione (isatin) derivatives and nalidixic acid
carbohydrazide, synthesis, antitubercular activity and pharmacophoric model
building
*
Tarek Aboul-Fadl , Fayzah A.S. Bin-Jubair, Omima Aboul-Wafa
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457 e Riyadh 14511, Saudi Arabia
a r t i c l e i n f o
a b s t r a c t
Article history:
Tuberculosis (TB) remains among the world’s great public health challenges. Worldwide resurgence of TB
is due to two major problems: the AIDS epidemic, which started in the mid-1980s, and the outbreak of
multidrug resistant (MDR) TB. Thus, there is an urgent need for anti-TB drugs with enhanced activity
against MDR strains. In recent years, Schiff bases of 1H-indole-2,3-diones are reported to exhibit anti-TB
activity. On the other hand, several quinolone antibacterial agents have been examined as inhibitors of
TB, as well as other mycobacterial infections. Accordingly, the current work involved design and
synthesis of Schiff bases of nalidixic acid carbohydrazide and isatin derivatives (5,6aef and 7,8aec).
Structures of the synthesized derivatives were confirmed on the bases of spectral methods of analyses.
Anti-TB activity of the synthesized derivatives was investigated against four Mycobacterium strains:
Mycobacterium intercellulari, Mycobacterium xenopi, Mycobacterium cheleneo and Mycobacterium smeg-
matis. Modest anti-TB activity was observed within the investigated compounds, however, compound 5f
Received 9 May 2010
Received in revised form
9 July 2010
Accepted 12 July 2010
Available online 8 August 2010
Keywords:
Schiff bases
Isatin derivatives
Nalidixic acid carbohydrazide
Antitubercular activity
Pharmacophore
MOE
revealed potent anti-TB activity with MIC 0.625
mg/ml, which is 20 times greater than the reference drug
isoniazid, INH, (MIC ¼ 12.5 g/ml). A hypothetical pharmacophore model was built using Molecular
m
Operating Environment (MOE) program and 10 compounds structurally related to the synthesized ones
with reported anti-TB activity. The Pharmacophoric model built revealed the necessity of the following
pharmacophoric features for anti-TB activity: aromatic center, hydrogen bond acceptor/metal ligator
center, hydrogen bond donor center and aromatic center/hydrophobic area. Theses features were
consistent with the found anti-TB activity of the tested compounds.
Ó 2010 Elsevier Masson SAS. All rights reserved.
1. Introduction
developnewanti-TBdrugs tocombat the spreadof TB, particularlyin
its hard-to-kill multidrug-resistant, persistent and latent forms.
Although drugs for treatment of tuberculosis (TB) have been
available for nearly 50 years, TB remains a global health crisis, killing
2e3 million people annually and for a global economic toll of $12
billion each year [1]. The recent emergence of multidrug-resistant
(MDR) and extensively drug-resistant (XDR) tuberculosis resulted in
a major setback in the global fight against TB. The prevailing situa-
tion is made worse by the continuous increase in the number of
immune-compromised patients livingwith HIV who are moreprone
toTB and other bacterial infections [2e4]. These results have further
stimulated research efforts globally [5]. No new drugs have been
developed specifically against mycobacteria since the 1960s and
only within the last few years have some promising drug candidates
emerged [6,7]. Thus, more than ever, there is an urgent need to
There are two basic approaches to develop a new drug for TB:
i
Synthesis of new analogues, modifications or derivatives of
existing compounds for shortening and improving TB treat-
ment [8].
ii Searching for novel structures, that the TB organism has never
been presented with before, for the treatment of MDR-TB [9].
To pursue this goal, the current work is directed to synthesize
derivatives starting from chemical moieties reported to have poten-
tial antimycobacterial activity. Indoline-2,3-dione (isatin) derivatives
are reported to show antitubercular activities [8,10]. Moreover, it was
recently reported that indoline-2-one structural scaffold as potent
DNA gyrase inhibitors [11]. DNA gyrase is a bacterial enzyme that
catalyzes the introduction of negative supercoils in a closed-circular
DNA using the energy of the ATP hydrolysis. Since it is found only in
* Corresponding author. Tel.: þ966 146 77341; fax: þ966 146 76220.
E-mail address: fadl@ksu.edu.sa (T. Aboul-Fadl).
0223-5234/$ e see front matter Ó 2010 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2010.07.020

T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
4579
prokaryotes and is vital for their survival, it has become an attractive
target for antibacterial agents [12]. Accordingly isatin is a versatile
lead molecule for designing of potential antitubercular agent. In view
of the antitubercular property of this pharmacophore, it was envis-
aged that its combined effect with an active moiety may result in
increased antitubercular activity [13]. In recent years, Schiff and
Mannich bases of isatins are reported to exhibit anti-TB activity.
Investigation of the structureeactivity relationships in 1H-indoline-
2,3-dione derivatives revealed that 5-halogenation, N-alkylation, and
N-Mannich bases were effective in causing a marked enhancement in
the activity against various bacteria [14]. Accordingly, design of the
Schiff’s bases of 5-bromo-1-substitued and/or 1-substitued isatin
(alkyl, aralkyl or Mannich bases) and nalidixic acid carbohydrazide
was undertaken. Evaluation of the anti-TB activity of the synthesized
Schiff’s bases together with the estimation of their pharmacophoric
model using Molecular Operating Environment (MOE) software were
of great interest.
solvents, the phenomena that hindered the structural verification
of these products by NMR. However, the mass spectra of these
compounds were in agreement with their structures. An interesting
observation appeared in the IR spectra of the Mannich derivatives,
7 and 8(aec), where distinguished absorption bands appeared
around 2813.70e2940.54 cmꢁ1 attributed to NeCH2eN. This
observation is consistent with similar reported compounds [16],
and is another evidence for the formation of the Mannich bases.
2.2. Antitubercular screening of the target compounds
The synthesized compounds, 5(aeg), 6(aeg), 7(aec) and 8(aec),
were evaluated for their antimycobacterial activity in vitro against
four Mycobacterium strains: Mycobacterium intercellulari (ATCC
35743), Mycobacterium xenopi (ATCC 14470), Mycobacterium chele-
neo (ATCC 35751) and Mycobacterium smegmatis (ATCC 35797) by
agar dilution method according to the protocol described in the
experimental section similar to that recommended by the National
Committee for Clinical Laboratory Standards (NCCLS) for the deter-
mination of MIC [17]. Isoniazid (INH) was used as a reference drug
and control experiments were done using a growth media free from
drugs or the tested compounds. Results of the in vitro antitubercular
activity of the tested compounds along with the standard drug for
comparison are given in Table 1. The data of the antitubercular
activity screening revealed that with the exception of compound 5f
all the other tested compounds did not show any considerable
activity. The lonely active compound, 5f was found to be 20 times
more potent than the first line antitubercular drug INH in vitro. It is
worthy to mention that the preliminary antimycobacterial evalua-
tion results showed that unlike N-alkyl derivatives of isatin, its
Mannich bases, 7 and 8(aec), are completely devoid of anti-TB
activity. Most probably this observation may be attributed to the
poor solubility of these derivatives in DMSO.
2. Results and discussion
2.1. Chemistry
ThedesignedSchiff’sbaseswereobtainedthrough2stepsreaction
as described in Scheme 1. The first step involved N-substitution of
isatin (1a) or 5-bromoisatin (1b) to obtain the corresponding 1-alkyl,
1-benzyl and 1-hydroxymethyl derivatives. 1-Alkyl or 1-benzylisatin
derivatives, 2 and 3(aee), were achieved in very good yields by
reaction of convenient alkyl halide or benzyl chloride with 1a and 1b
respectively in DMF using 1.5 equivalent of K2CO3 at 80 ꢀC [13].
However, 1-hydroxymethyl isatin derivatives (2f and 3f), were
obtained in a good yield by the reaction of appropriate isatinwith 40%
formaldehyde in water [13]. The second step is the condensation of
the 1-substituted isatins with nalidixic acid carbohydrazide (4). The
later prepared according to a reported procedures [15]. The prepared
derivatives were confirmed by spectral methods of analysis and were
consistent with the proposed structures.
2.3. Pharmacophore generation
Mannich bases on the other hand were obtained from the
reaction of the convenient Schiff’s bases 5a or 6a with formaline
and appropriate secondary amine, Scheme 2. Unfortunately the
crystalline products obtained were insoluble in the available
The aim of this approach is to generate and assess a pharmaco-
phore model (hypothesis) derived from compounds of reported
anti-TB activity [18]. Three steps are usually employed for 3D
pharmacophore-based applications: First, it is necessary to
O
O
R
R
A or B
O
O
N
N
CH2R1
H
A: R1CH2X, K2CO3, DMF, 80oC, 4-16h.
B: HCHO, H2O, Reflux, 2h. 2 and 3 f
1a: R = H
1b: R = Br
R
O
O
N
C2H5OH/H+
N
N
H
+
Reflux
N
R1
O
O
O
N
O
N
CH3
O
CH2CH3
OH
NHNH2
C
H3C
N
N
H3C
N
CH2CH3
CH2CH3
4
C:1. ClCO2C2H5,TEA, DCM,0-4oC, 30 min.
2. H2NNH2, 4h.
Scheme 1.

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T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
R
R
O
O
O
O
N
N
N
H
N
H
A
N
N
N
N
CH3
O
O
R1H2C
N
N
CH3
H
CH2CH3
CH2CH3
A: HCHO, C2H5OH, (C2H5)2N or
7, R = H
8, R = Br
5a, R= H
6a, R=Br
H
H
N
N
R1= a, (C2H5)2N; b,
N
N
or
N
c,
;
CH3
N
CH3
Scheme 2.
Table 1
activity as it was published recently in W. S. Abdel-Aal et al [18].
The classical pharmacophoric features include hydrogen bond
acceptors (Acc), hydrogen bond donors (Don), charged or ioniz-
able groups (Cat and Ani), hydrophobic (Hyd), metal ligator (ML)
and/or aromatic rings (Aro) together with geometrical constraints
like distances, angles and dihedral angles. To carry out pharma-
cophore analyses, relevant features in a molecule need to be
identified. The initial pharmacophoric query was performed and it
is composed of 4 features, as given in Table 2 and illustrated
graphically in Fig. 1.
In vitro anti-TB activity of the synthesized compounds.
Compound
MIC (mg/ml)/Mycobacterium strain
M. intercellulari
M. Xenopi
M. cheleneo
M. smegmatis
5a
5b
5c
5f
6a
6c
6f
NA
NA
NA
100
200
200
0.625
200
NA
200
200
0.625
NA
NA
NA
200
0.625
NA
200
0.625
NA
100
50
100
50
NA
50
50
INH
12.5
12.5
12.5
12.5
NA: no activity at 200 mg/ml
Table 2
Pharmacophoric and structure features of the training set.
generate 3D structures of training set molecules of known biolog-
ical activity. This is generally achieved using automated 3D struc-
ture generation programs that translate 2D molecular descriptions
to 3D ones. Second, the assignment of the pharmacophoric
features. Finally, the application of a method for undertaking
conformational searching of databases for new structures matching
the generated pharmacophoric features [19]. These steps will be
expounded in the building of a hypothetical pharmacophoric
model for certain reported anti-TB compounds and testing the
synthesized compounds 5(aeg), 6(aeg), 7(aec) and 8(aec).
Chemical Computing Group’s Molecular Operating Environment
(MOE) is used for pharmacophore building. In MOE, 3D pharma-
cophore queries can contain locations of the features or chemical
groups as well as restrictions on shape. Restriction on shape can be
imposed by specifying the included and/or excluded volume areas.
Furthermore, a consensus query from not one but a set of aligned
molecules can be used for the 3D pharmacophore database search
which provides high control. Consequently, both partial and
systemic matching as well as flexible matching rules are offered
[20]. The program expresses the degree of mapping of a given
compound to a generated hypothetical model in term of rmsd
value, which in turn correlated with compound’s activity. Rmsd
value refers to the root of the mean square distance between the
query features and their matching ligand target points [21].
Pharmacophoric features Structure features
F1: Aro
F2: Acc/ML
F3: Don
p-substituted phenyl, 4-pyridyl
C]O
CONHeN]
F4: Aro/Hyd
Methyl, cyclohexyl, p-substituted phenyl, 4-pyridyl,
1-morpholinyl, 4-nitro-five membered heterocycles
(furan or thiophene)
2.3.1. Generating a query
The developed query can be based on one conformation of the
most active molecule. Alternatively, it can be based on an align-
ment of several active molecules (training set), a method that is
used here. Such an alignment can be obtained by using MOE’s
flexible alignment, and all conformations of the molecules were
considered for the alignment [21]. A hypothetical pharmacophore
model was built using MOE program and 10 compounds struc-
turally related to the synthesized ones with reported anti-TB
Fig. 1. Pharmacophore features and distances.

T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
4581
Table 3
Rmsd values of the hit set and their anti-TB activity (MIC).
Compound
MIC (
m
g/ml)
Rmsd
5a
5b
5c
5d
5e
5f
5g
6a
6b
6c
6d
6e
6f
6g
7a
7b
7c
8a
8b
8c
INH
100
200
200
NA
0.5995
0.7413
0.7410
0.7405
0.7404
0.2479
0.7412
0.7431
0.7420
0.7417
0.7414
0.7409
0.2508
0.7416
0.7407
0.7411
0.7408
0.7411
0.7403
0.7415
0.2890
NA
0.625
NA
200
NA
100
NA
NA
50
NA
NA
NA
NA
NA
NA
NA
12.5
Fig. 3. Inadequate fitting of 6a (MIC 200 mg/ml) with the pharmacophore.
From these data it can be concluded that the bulky N1-benzyl
group in compounds 5f and 6f result in change of their orientation
therefore, the two compounds have very good fit with the phar-
macophore, similar to what was obtained with the reference drug
INH. Nonetheless, the observed modest anti-TB activity of
2.3.2. Consensus query searching
A search of the test set using this new consensus query resulted
in 2 hits, 5f and 6f. Results are listed in Table 3 and revealed that the
lower the rmsd values the higher inhibitory activity. In these hits,
the amidic moiety CONHeN]C fitted the region of the Don, F3,
while the amidic carbonyl group fitted the region of the Acc/ML, F2.
Superimposition of compound 5f, the most active compounds, with
the pharmacophoric model is illustrated by Fig. 2. 5f has rmsd value
compound 6f (MIC 50
mg/ml) may be attributed to the steric
hindrance of bromine atom with the fitting of benzene ring of isatin
into the aromatic pocket of the receptor.
3. Conclusion
of 0.2479 and MIC 0.625 mg/ml. In addition to F1 and F4, fitting the
In the current work a promising anti-TB lead compound (5f) of
the Schiff bases of isatin derivatives and nalidixic acid carbohy-
drazide has been emerged and a pharmacophoric features have
been recognized. Consequently, further optimization of the anti-TB
activity for these derivatives are requested and are currently in
progress.
isatin aligned to the hydrophobic/aromatic feature F1 and the
naphthyridine ring fitted to the aromatic feature F4. On the other
hand, partially matching compounds to the pharmacophoric model
is displayed by Fig. 3. Compound 6a, with MIC 200
mg/ml, was
selected as a representative example of the practically poor
matching compounds showed fitting only to F1 and F4 features of
the pharmacophoric model, extent of deviation of fitting from the
other features was reflected by increased rmsd value.
4. Experimental
4.1. General notes and methods
Melting Points were determined on Stuart melting point appa-
ratus (Stuart Scientific, England) and were uncorrected. Precoated
silica gel plates, 60G F254, obtained from Merck, Darmstadt
(Germany) and were used for thin layer chromatography (TLC). Spots
were visualized by usingeither UV-lamp at 254 nmor iodine. Infrared
(IR) Spectra were recorded as KBr disk using Perkin Elmer FTeIR
apparatus at the research center, College of Pharmacy, King Saud
University, Saudi Arabia. The data are given in nmax (cmꢁ1). NMR
Spectrawere determined ineither DMSO-d6 orCDCl3 andrecordedon
Bruker NMR Spectrophotometer (500 MHz) at the research center,
CollegeofPharmacy, KingSaudUniversity, Saudi Arabia. Thechemical
shifts are expressed as
d values (ppm) relative to tetramethylsilane
(TMS) as internal standard. The J constant was given in (Hz). Mass
spectraweretakenon aVarian320 e MSspectrometerattheresearch
center, College of Pharmacy, King Saud University, Saudi Arabia. Mass
spectral data were given as m/z (intensity%).
The anti-TB screening was carried out at the research center,
College of Pharmacy, King Saud University, Saudi Arabia.
Pharmacophore building was carried out using “Molecular
Operating Environment (MOE) version 2006.08”, Chemical
Computing Group Inc., 1010 Sherbrooke Street West, Suite 910,
Montreal, H3A 2R7, Canada. Program operated under “Windows
Fig. 2. Superposition of 5f (MIC 0.625 mg/ml) with the query.

4582
T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
XP” operating system installed on an Intel Pentium IV PC with
a 2.8 MHz processor and 512 RAM.
2976.19, 2904.76 (CeH aliphatic), 3057.62 (CeH aromatic), 3367.14
(OeH); 1H NMR dH(DMSO-d6): 5.09 (2H, d, J ¼ 5.5, NCH2OH), 6.45
(1H, bs, NCH2OH), 7.22 (1H, d, J ¼ 10, C7H), 7.75 (1H, s, C4H), 7.86
(1H, d, J ¼ 10, C6H). 13C NMR dC (DMSO-d6): 63.59 (NCH2OH), 114.37
(C4), 115.77 (C7), 119.57 (C6), 127.24 (C3a), 140.44 (C7a), 149.64 (C5),
157.67 (C2), 182.74 (C3). MS m/z(%): 43.8 (100%), 209.6 (1.07%), 224.7
(6.83%), 255.2 (0.53%), 256.6 (2.28%), 257.8 (1.96%), 258.7 (1.18%).
Building blocks 2(aef), 3(aef) and 4 were prepared according to
the reported procedures [13,15]. Compounds 2(aef), 3a and 4 were
described in literature, melting points and spectral data for these
compounds are consistent with the reported ones [13,15,22e24].
Data that were not found in the literature are given in the following
section:
4.2. Synthesis of Schiff’s bases of isatin and its derivatives and
carbohydrazide of nalidixic acid 5(aeg) and 6(aeg)
4.1.1. 5-Bromo-1-ethylindolin-2,3-dione (3b)
Yield: 97%; m.p. 230e231 ꢀC (from EtOH). IR nmax/cmꢁ1: 1120.33
(CeBr), 1475.76 (CeN), 1604.31, 1684.02 (C]O amidic), 1750.22
(C]O), 2853.34, 2879.63, 2922.01 (CeH aliphatic), 3095.24 (CeH
aromatic). 1H NMR dH(DMSO-d6): 1.20 (3H, t, J ¼ 7, NCH2CH3), 3.19
(2H, q, J ¼ 6.25, NCH2CH3), 6.69 (1H, d, J ¼ 9, C7H), 7.41 (1H, dd,
J1 ¼ 2, J2 ¼ 9, C6H), 7.66 (1H, bs, C4H). 13C NMR dC (DMSO-d6): 14.74
(NCH2CH3), 37.01 (NCH2CH3), 104.43 (C4), 113.98 (C7), 116.35 (C6),
136.67 (C3a), 136.74 (C7a), 150.30 (C5), 169.04 (C2), 200.80 (C3). MS
m/z(%): 117.0 (100%), 156.0 (4.04%), 183.0 (6.04%), 184.0 (75.96%),
211.0 (0.58%), 225.0 (12.67%), 253.0 (56.40%), 254.0 (3.15%), 255.0
(50.23%), 256.0 (1.66%).
4.2.1. General procedures
A stirred mixture of appropriate isatin or its derivative, 1a, 1b, 2
(aef) and 3 (aef), (0.5 mmol) and 4 (0.12 g, 0.5 mmol) in EtOH
acidified with 4 drops of glacial acetic acid was refluxed for
a specified time (4e13 h) and the reaction progress monitored by
TLC. The reaction mixture was then concentrated, cooled and
filtered. The filtrate was either crystallized by the appropriate
solvent or washed thoroughly with ethanol.
4.2.2. 1-Ethyl-1,4-dihydro-7-methyl-4-oxo-N0-(2-oxoindolin-3-
ylidene)-1,8-naphthyrid-ine-3-carbohydrazide (5a)
4.1.2. 5-Bromo-1-propylindolin-2,3-dione (3c)
Yield: 79%; m.p. 301e305 ꢀC (charring, from EtOH). IR nmax
/
Yield: 92%; m.p. 127e130 ꢀC(from EtOH). IR nmax/cmꢁ1: 1114.72
(CeBr), 1469.52 (CeN), 1608.51, 1676.06 (C]O amidic), 1735.58 (C]
O), 2928.24 (CeH aliphatic), 3095.24 (CeH aromatic). 1H NMR
dH(CDCl3): 0.99 (3H, bs, NCH2CH2CH3), 1.72 (2H, bs, NCH2CH2CH3),
3.68 (2H, bs, NCH2CH2CH3), 6.83 (1H, bs, C7H), 7.68 (2H, bs, C6 and
C4H).13C NMR dC (CDCl3): 11.28 (NCH2CH2CH3), 20.55 (NCH2CH2CH3),
41.95 (NCH2CH2CH3),111.92 (C4),116.37 (C7),118.74 (C6),128.10 (C3a),
140.49 (C7a), 149.83 (C5), 157.46 (C2), 182.42 (C3). MS m/z(%): 85.0
(0.80%), 156.0 (10.25%), 183.0 (11.67%), 184.0 (56.49%), 210.0 (100%),
211.0 (46.77%), 225.0 (9.52%), 267.0 (67.18%), 268.0 (8.70%), 269.0
(65.62%), 270.0 (8.27%).
cmꢁ1: 1441.31 (NeN), 1463.87 (CeN), 1541.37, 1575.84 (C]N),
1611.45, 1679.04 (C]O amidic), 2940.18, 2963.99 (CeH aliphatic),
3062.91 (CeH aromatic), 3348.62 (NeH). MS m/z(%): 103.0
(16.00%), 104.0 (30.00%), 118.0 (12.60%), 131.0 (25.10%), 132.0
(20.60%), 133.0 (4.90%), 145.0 (6.40%), 146.0 (4.90%), 160.0 (16.40%),
161.0 (2.80%), 173.0 (4.70%), 187.0 (45.60%), 188.0 (60.80%), 203.0
(1.80%), 215.0 (100%), 231.0 (7.60%), 246.0 (0.40%), 347.0 (34.20%),
374.0 (0.90%), 375.0 (14.20%), 376.0 (3.00%), 377.0 (0.50%).
4.2.3. 1-Ethyl-1,4-dihydro-7-methyl-N0-(1-methyl-2-oxoindolin-3-
ylidene)-4-oxo-1,8-naphthyridine-3-carbohydrazide (5b)
Yield: 57%; m.p. 312 ꢀC (from DCM). IR nmax/cmꢁ11441.53 (NeN),
1467.98 (CeN), 1541.32 (C]N), 1611.82, 1682.67 (C]O amidic),
2934.16, 2957.97 (CeH aliphatic), 3056.73 (CeH aromatic), 3446.32
4.1.3. 1-Allyl-5-bromoindolin-2,3-dione (3d)
Yield: 98%; m.p. 87e90 ꢀC(from EtOH). IR nmax/cmꢁ1: 904.69,
995.35, 1647.62 (CeH allyl), 1125.41 (CeBr), 1471.42 (CeN), 1606.55,
1674.30 (C]O amidic), 1742.47 (C]O), 2854.00, 2927.23 (CeH
aliphatic), 3096.98 (CeH aromatic). 1H NMR dH(CDCl3): 4.38 (2H, d,
J ¼ 5, NCH2CH]CH2), 5.35 (2H, d, J ¼ 4, NCH2CH]CH2), 5.81e5.88
(1H, m, NCH2CH]CH2), 6.83 (1H, d, J ¼ 8, C7H), 7.70 (1H, dd, J1 ¼1.5,
J2 ¼ 8, C6H), 7.74 (1H, bs, C4H). 13C NMR dC (CDCl3): 42.62
(NCH2CH]CH2), 112.57 (C4), 116.67 (C7), 118.78 (NCH2CH]CH2),
118.94 (C6), 128.14 (NCH2CH]CH2), 130.00(C3a), 140.47 (C7a), 149.52
(C5), 157.15 (C2), 182.00 (C3). MS m/z(%): 82.0 (1.15%), 130.0 (100%),
156.0 (10.78%), 183.0 (6.07%), 184.0 (13.43%), 225.0 (1.61%), 265.0
(45.92%), 266.0 (7.26%), 267.0 (43.59%), 268.0 (5.40%).
(NeH). 1H NMR dH(CDCl3): 1.57 (3H, t, J ¼ 7.25, N1 CH2CH3), 2.71
0
0
(3H, s, C7 CH3), 3.35 (3H, s, N1CH3), 4.62 (2H, q, J ¼ 7, N1CH2CH3),
6.89 (1H, d, J ¼ 7.5, C7H), 7.14 (1H, t, J ¼ 7.75, C5H), 7.33 (1H, d, J ¼ 8,
0
C4H), 7.40 (1H, t, J ¼ 8.75, C6H), 7.90 (1H, d, J ¼ 7.5, C6 H), 8.86 (1H, d,
J ¼ 8, C5 H), 9.05 (1H, s, C2 H), 15.38 0(1H, s, CONH). 13C NMR dC
0
0
0
(CDCl3): 15.28 (N1 CH2CH3), 25.15 (C7 CH3), 25.69 (N1CH3), 47.07
0
0
0
(N1 CH2CH3), 108.53 (C7), 112.01 (C5 ), 120.49 (C3a), 120.64 (C6 ),
0
121.49 (C4a0), 121.96 (C5), 122.97 (C4), 131.09 (C3 ), 137.01 (C3), 137.25
0
0
(C6), 143.80 (C2 ), 148.680(C8a0),148.73 (C7a),160.24 (C2), 163.32 (C7 ),
0
163.37 (C9 ), 176.32 (C4 ). MS m/z(%): 43.8 (100%), 103.3 (17.68%),
104.8 (3.12%), 131.4 (5.10%), 143.9 (0.68%), 147.0 (8.19%), 162.7
(2.82%), 176.6 (2.71%), 230.2 (1.14%), 231.3 (5.46%), 244.7 (1.32%),
388.9 (0.91%), 391.3 (1.00%).
4.1.4. 1-Benzyl-5-bromoindoline-2,3-dione (3e)
Yield: 98%; m.p. 105e108 ꢀC(from EtOH). IR nmax/cmꢁ1: 1126.18
(CeBr), 1470.07 (CeN), 1610.60, 1652.97 (C]O amidic), 1731.81 (C]
O), 2854.11, 2928.24 (CeH aliphatic), 3032.05, 3063.44 (CeH
aromatic). 1H NMR dH(DMSO-d6): 4.91 (2H, s, NCH2-ph), 6.92 (1H, d,
J ¼ 8, C6H), 7.01e7.58 (6H, m, C6H and phenyl protons), 7.74 (1H, d,
J ¼ 11.5, C4H). 13C NMR dC (DMSO-d6): 43.50 (NCH2-ph), 111.06 (C4),
113.63, 127.18, 127.79, 129.10, 135.67, 135.98 (phenyl carbons),
115.55 (C7), 120.02 (C6), 128.02 (C3a), 140.09 (C7a), 149.71 (C5),
158.40 (C2), 182.02 (C3). MS m/z(%): 90.0 (3.72%), 91.0 (100%), 156.0
(1.45%), 183.0 (0.71%), 184.0 (0.96%), 210.0 (0.73%), 225.0 (2.63%),
315.0 (14.86%), 316.0 (2.97%), 317.0 (15.01%).
4.2.4. 1-Ethyl-N0-(1-ethyl-2-oxoindolin-3-ylidene)-1,4-dihydro-7-
methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (5c)
Yield: 75%; m.p. 278 ꢀC(from DCM). IR nmax/cmꢁ1: 1442.21
(NeN), 1464.90, 1493.12 (CeN), 1508.40, 1571.72 (C]N), 1610.72,
1690.69 (C]O amidic), 2977.65 (CeH aliphatic), 3055.48 (CeH
aromatic), 3447.34 (NeH). 1H NMR0 dH(CDCl3): 1.34 (3H, t, J ¼ 7,
0
N1CH2CH3), 1.56 (3H, t, J ¼ 7.25, N1 CH2CH3), 2.69 (3H, s, C7 CH3),
0
3.91 (2H, q, J ¼ 7, N1CH2CH3), 4.61 (2H, q, J ¼ 7, N1 CH2CH3), 6.90
(1H, d, J ¼ 7.5, C7H), 7.12 (1H, t, J ¼ 7.5, C5H), 7.032 (1H, d, J ¼ 8, C4H),
7.38 (1H, t, J ¼ 7.5, C6H), 7.90 (1H, d, J ¼ 7.5, C6 H), 8.86 (1H, d, J ¼ 8,
C5 H), 9.04 (1H, s, C2 H), 15.36 (1H, s, CONH). 13C NM0R dC (CDCl3):
0
0
0
4.1.5. 5-Bromo-1-hydroxymethylindolin-2,3-dione (3f)
12.95 (N1CH2CH3), 15.24 (N1 CH2CH3), 25.25 (C7 CH03), 34.35
Yield: 75%; m.p. 128e131 ꢀC(from AcOEt). IR nmax/cmꢁ1: 1088.73
(CeBr), 1258.51 (CeO), 1474.80 (CeN), 1607.10, 1730.65 (C]O),
(NCH2CH3), 46.99 (N1 CH2CH3), 108.51 (C7), 112.03 (C5 ), 120.60
0
0
0
(C3a), 120.75 (C6 ), 121.45 (C4a0), 122.09 (C5), 122.76 (C4), 130.99 (C3 ),

T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
4583
0
137.04 (C3), 137.39 (C6), 142.99 (C2 ), 148.69 (C8a0), 148.89 (C7a0),
N1CH2ph), 6.76 (1H, d, J ¼ 8, C7H), 7.12 (1H, t, J ¼ 7.5, C5H), 7.029e7.39
(7H, m, C4H, C6H0and phenyl protons), 7.93 (1H, d, J ¼ 7.5, C6 H), 8.88
0
0
0
158.89 (C2), 163.20 (C7 ), 163.30 (C9 ), 176.55 (C4 ). MS m/z(%): 42.8
(100%), 101.2 (2.26%), 103.9 (10.98%), 117.8 (1.05%), 130.2 (1.30%),
132.8 (21.22%), 143.8 (1.64%), 147.0 (10.58%), 160.0 (2.69%), 161.0
(30.02%), 174.1 (2.59%), 186.5 (9.66%), 188.3 (2.90%), 189.3 (0.51%),
203.2 (2.58%), 214.9 (1.58%), 230.8 (0.81%), 245.3 (1.53%), 333.7
(0.65%), 346.8 (2.65%), 375.2 (2.49%), 401.8 (0.50%), 404.4 (1.82%),
405.6 (0.64%).
(1H, d, J ¼ 8.5, C5 H), 9.07 (1H, s, C2 H), 15.420(1H, s, CONH). 13C NMR
0
0
dC (DMSO0-d6): 15.38 (N1 CH2CH3), 25.19 (C70CH3), 43.44 (N1CH2ph),
47.07 (N1 CH2CH3), 110.03 (C7), 110.94 (C5 ), 120.01 (C3a), 120.37
0
(C6 ), 121.43 (C4a0), 121.92 (C5), 122.27 (C4), 127.39, 0127.83 128.93,
132.68, 135.73, 135.84 (phenyl carbons), 131.39 (C3 ), 136.45 (C3),
0
137.69 (C6), 144.03 (C2 ), 148.48 (C8a0), 149.37 (C7a), 163.12 (C2),
0
0
0
163.72 (C7 ), 164.24 (C9 ), 176.55 (C4 ). MS m/z(%): 43.8 (100%), 90.7
(1.21%), 103.0 (6.91%), 104.1 (8.54%), 117.0 (7.58%), 131.2 (0.78%),
132.8 (22.71%), 145.8 (3.19%), 159.8 (8.66%), 173.1 (1.85%), 188.4
(2.32%), 201.9 (1.30%), 210.2 (6.92%), 214.5 (1.80%), 230.3 (1.16%),
231.4 (0.99%), 238.7 (0.54%), 246.8 (22.17%), 332.2 (3.31%), 346.2
(2.25%), 464.6 (0.45%), 465.8 (2.71%), 466.9 (2.25%).
4.2.5. 1-Ethyl-1,4-dihydro-7-methyl-4-oxo-N0-(2-oxo-1-
propylindolin-3-ylidene)-1,8-naphthyridine-3-carbohydrazide (5d)
Yield: 237e240%; m.p. 278 ꢀC(from DCM). IR nmax/cmꢁ1: 1444.11
(NeN), 1463.45, 1487.09 (CeN), 1508.12, 1541.77, 1575.71 (C]N),
1608.34, 1674.71 (C]O amidic), 2927.70 (CeH aliphatic), 3023.81
(CeH aromatic), 3446.34 (NeH). 1H NMR dH(CDCl3): 1.02 (3H, t,
0
J ¼ 7.5, N1CH2CH2CH3), 1.57 (3H, t, J ¼07, N1 CH2CH3), 1.77e1.82 (2H,
4.2.8. 1-Ethyl-1,4-dihydro-N0-(1-hydroxymethyl-2-oxoindolin-3-
ylidene)-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (5g)
Yield: 83%; m.p. 275e278 ꢀC(charring, from EtOH). IR nmax/cmꢁ1
1206.10 (CeO), 1440.81 (NeN), 1464.06, 1484.97 (CeN), 1540.76,
1576.16 (C]N), 1610.04, 1678.43 (C]O amidic), 1695.95 (C]O),
2936.28, 2960.09 (CeH aliphatic), 3058.24 (CeH aromatic), 3340.74
(OeH and NeH). MS m/z(%): 57.0 (100%), 103.0 (22.30%), 104.0
(35.00%), 118.0 (7.60%), 131.0 (23.40%), 132.0 (24.90%), 145.0 (6.50%),
160.0 (12.80%), 163.2 (1.04%), 173.0 (5.70%), 175.7 (0.97%), 187.0
(49.50%), 188.0 (60.10%), 190.0 (1.30%), 203.0 (1.60%), 215.0 (100%),
230.3 (0.56%), 231.0 (2.80%), 246.6 (0.27%), 332.5 (0.10%), 347.0
(37.70%), 375.0 (12.90%), 403.9 (0.13%), 405.2 (0.20%), 406.1 (0.01%),
407.1 (0.15%).
m, N1CH2CH2CH3), 2.70 (3H, s, C7 CH3), 3.81 (3H, t, J ¼ 7.5,
0
N1CH2CH2CH3), 4.62 (2H, q, J1 ¼ 14.5, J2 ¼ 21.5, N1 CH2CH3), 6.90
(1H, d, J ¼ 8, C7H), 7.12 (1H, t, J ¼ 7.5, C5H), 7.33 (1H, d, J ¼ 8, C4H),
0
7.37 (1H, t, J ¼ 7.75, C6H), 7.90 (1H, d, J ¼ 7.5, C6 H), 8.87 (1H, d, J ¼ 8,
C5 H), 9.05 (1H, s, C2 H), 15.35 (10H, s, CONH). 13C NMR dC (CDCl3):
0
0
11.41 (N1CH2CH2CH3), 15.27 (N1 CH2CH3), 20.96 (N1CH2CH2CH3),
0
0
25.1 (C7 CH3), 41.37 (N1CH2CH2CH3), 47.07 (N1 CH2CH3), 108.83 (C7),
112.15 (C5 ), 120.00 (C3a), 120.60 (C6 ), 121.49 (C4a0), 122.04 (C5),
0
0
0
0
122.73 (C4), 131.00 (C3 ), 137.04 (C3), 137.31 (C6), 143.34 (C2 ), 148.68
(C8a0), 148.74 (C7a), 160.16 (C2), 163.28 (C7 ), 167.00 (C9 ), 176.35 (C4 ).
MS m/z(%): 43.8 (100%), 102.6 (25.57%), 104.0 (12.03%), 118.0
(11.08%), 130.6 (7.05%), 131.7 (13.99%), 145.8 (6.04%), 146.9 (18.76%),
160.1 (11.55%), 172.7 (4.94%), 175.5 (0.41%), 187.4 (1.60%), 188.3
(4.64%), 203.4 (1.49%), 214.9 (2.93%), 229.4 (0.48%), 230.6 (1.53%),
246.7 (3.32%), 346.7 (2.94%), 375.4 (2.03%), 417.0 (10.45%), 419.5
(3.76%).
0
0
0
4.2.9. N0-(5-Bromo-2-oxoindolin-3-ylidene)-1-ethyl-1,4-dihydro-
7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (6a)
Yield: 99%; m.p. 362 ꢀC(from DMF). IR nmax/cmꢁ1 1111.32 (CeBr),
1441.92 (NeN), 1466.03 (CeN), 1542.34 (C]N), 1609.54, 1664.04
(C]O amidic), 1666.42 (C]O nalidixic acid hydrazide), 2935.12,
2982.74 (CeH aliphatic), 3095.24 (CeH aromatic), 3447.18 (NeH).1H
4.2.6. N0-(1-Allyl-2-oxoindolin-3-ylidene)-1-ethyl-1,4-dihydro-7-
methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (5e)
Yield: 58%; m.p. 281 ꢀC(from DCM). IR nmax/cmꢁ1: 910.91,
1018.21, 1656.20 (CeH allyl), 1441.89 (NeN), 1474.89 (CeN),
1542.64 (C]N), 1608.58, 1679.16 (C]O amidic), 2891.68, 2963.11
(CeH aliphatic), 3053.19 (CeH aromatic), 3447.34 (NeH). 1H0NMR
NMR dH(, DMSO-d6): 1.44 (3H, m, N1 CH2CH3), 2.71 (3H, s, C7 CH3),
0
0
0
4.64 (2H, m0, N1 CH2CH3), 6.91 (1H, dd, J1 ¼8.5, J2 ¼ 8, C7H), 7.52 (1H,
d, J ¼ 7.5, C6 H), 7.59 (1H, d, J ¼ 7.5, C6H), 8.59 (1H, s, C4H), 8.64 (1H, d,
0
0
J ¼ 8, C5 H), 9.28 (1H, s, C2 H), 13.740(1H, s, NH), 14.96 (1H, s, CONH).
dH(CDCl3): 1.56 (3H, t, J ¼ 7.25, N1 CH2CH3), 2.68 (3H, s, C7 CH3),
13C0NMR dC (DMSO-d6): 15.48 (N1 CH2CH3), 25.30 (C7 CH3), 46.00
0
0
0
0
4.48 (2H, d, J ¼ 5, N1CH2CH]CH2), 4.60 (2H, q, J1 ¼ 14.5, J2 ¼ 21.5,
(N1 CH2CH3),112.00 (C4),113.77 (C5 ),115.01 (C7),120.00 (C6 ),121.00
0
0
N1 CH2CH3), 5.25 (1H, d, J ¼ 10.5, N1CH2CH]HCH), 5.30 (1H, d,
(C4a0),122.00 (C6),123.86 (C3a),133.89 (C3 ),136.56 (C7a),137.40 (C3),
0 0
146.00 (C2 ), 148.00 (C8a0), 148.99 (C5), 159.98 (C2), 163.00 (C7 ),
J ¼ 17.5, N1CH2CH]HCH), 5.85e5.90 (1H, m, N1CH2CH]CH2),
6.87 (1H, d, J ¼ 8, C7H), 7.12 (1H, t, J ¼ 7.75, C5H), 7.30e7.36 (2H,
0
0
165.00 (C9 ),176.00 (C4 ). MS m/z(%): 45.0 (100%),132.1 (1.21%),145.1
(3.51%), 160.0 (6.29%), 183.3 (1.14%), 186.8 (1.95%), 187.9 (4.09%),
202.3 (11.43%), 208.0 (26.57%), 213.6 (0.55%), 215.7 (5.55%), 222.8
(3.16%), 245.7 (1.01%), 411.0 (0.48%), 426.5 (4.08%), 435.9 (3.32%),
452.9 (7.31%), 454.8 (0.56%), 456.0 (2.17%).
0
m, C4H and C6H), 7.89 (1H, d, J ¼ 7.5, C6 H), 8.84 (1H, d, J ¼ 8,
C5 H), 9.04 (1H, s, C2 H), 15.34 (1H, s, CONH). 13C NMR dC (CDCl3):
0
0
0
0
15.26 (N1 CH2CH3), 25.13 (C7 CH3), 42.03 (N1CH2CH]CH2), 47.08
0
0
(N1 CH2CH3), 109.48 (C7), 112.07 (C5 ), 118.15 (N1CH2CH]CH2),
120.54 (C3a0), 120.59 (C6 ), 121.49 (C4a0), 121.94 (C5), 122.93 (C4),
0
130.98 (C3 ), 131.17 (N1CH2CH]CH2), 137.96 (C3), 136.99 (C6),
4.2.10. N0-(5-Bromo-1-methyl-2-oxoindolin-3-ylidene)-1-ethyl-
1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide
(6b)
143.00 (C20), 148.66 (C80a0), 148.75 (C7a), 159.84 (C2), 163.25 (C7 ),
163.39 (C9 ), 176.34 (C4 ). MS m/z(%): 41.0 (100%), 103.0 (9.97%),
104.9 (3.51%), 118.2 (2.68%), 131.6 (5.40%), 145.1 (9.68%), 160.1
(12.79%), 172.3 (1.20%), 184.5 (17.98%), 186.9 (0.51%), 188.2 (9.02%),
203.1 (1.41%), 214.9 (0.53%), 230.3 (0.67%), 231.1 (0.66%), 246.5
(3.72%), 330.9 (1.69%), 347.0 (1.36%), 414.3 (2.29%), 415.7 (4.34%),
417.2 (5.52%).
0
0
Yield: 59%; m.p. 369e372(charring, from DMF). IR nmax/cmꢁ1
:
1101.83 (CeBr), 1441.98 (NeN), 1478.41 (CeN), 1543.16 (C]N),
1611.30, 1679.50 (C]O), 2924.59 (CeH aliphatic), 3011.90, 3071.43
(CeH aromatic), 3446.70 (NeH). MS m/z(%): 40.2 (100%), 131.9
(8.48%),145.6 (1.63%),159.0 (0.92%),172.8 (3.20%),183.7 (1.35%),188.3
(3.80%),197.7 (3.40%), 203.3 (0.76%), 210.0 (3.12%), 214.6 (1.11%), 225.6
(5.49%), 231.3 (0.61%), 239.5 (1.37%), 245.1 (1.26%), 254.9 (2.81%),
425.1 (1.18%), 452.6 (0.93%), 466.7 (1.16%), 470.2 (1.49%).
4.2.7. N0-(1-Benzyl-2-oxoindolin-3-ylidene)-1-ethyl-1,4-dihydro-7-
methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (5f)
Yield: 55%; m.p. 292 ꢀC(from DCM). IR nmax/cmꢁ11441.03 (NeN),
1466.24, 1489.30 (CeN), 1510.87, 1541.11 (C]N), 1611.46, 1679.65
(C]O amidic), 2926.03 (CeH aliphatic), 3058.36 (CeH aromatic),
4.2.11. N0-(5-Bromo-1-ethyl-2-oxoindolin-3-ylidene)-1-ethyl-1,4-
dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (6c)
Yield: 93%; m.p. 331 ꢀC(from EtOH). IR nmax/cmꢁ1: 1106.76
(CeBr), 1441.59 (NeN), 1473.49 (CeN), 1543.54 (C]N), 1608.48,
3446.27 (NeH). 1H NMR dH(CDCl3) 1.58 (3H, 0t, J ¼ 6.5, N1 CH2CH3),
0
0
2.73 (3H, s, C7 CH3), 4.63 (2H, q, J ¼ 7.5, N1 CH2CH3), 5.08 (2H, s,

4584
T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
0
1682.08 (C]O), 2922.00 (CeH aliphatic), 3071.43 (CeH
aromatic), 3447.43 (NeH). 1H NMR dH(DMSO-d6): 1.150e1.25 (3H,
and phenyl0 protons), 8.04 (1H, bs, C4H), 8.84 (1H, bs, C5 H), 9.05
(1H, bs, C2 H), 15.40 (1H, s, CONH). 13C NMR dC (CDCl3): 15.22
0
0
0
0
m, N1CH2CH3), 1.43 (3H, m, N1 CH2CH3), 2.69 (3H, s, C7 CH3), 3.80
(N1 CH2CH3), 25.10 (C70CH3), 43.57 (N1CH2ph), 47.10 (N1 CH2CH3),
0
0
(2H, m, N1CH2CH3), 4.62 (2H, m, N1 CH2CH3), 7.19 (1H, d, J ¼ 15,
111.08 (C4), 111.97 (C5 ), 115.97 (C7), 120.61 (C6 ), 121.53 (C4a0),
0
C7H), 7.54 (1H, d, J ¼ 10, C6 H), 7.62 (1H, m, C6H), 7.70 (1H, s, C4H),
122.46 (C6), 124.71 (C3a), 127.41, 127.88, 128.87, 129.50, 134.99,
135.25 (phenyl carbons), 133.28 (C3 ), 135.51 (C7a), 136.97 (C3),
0
0
0
8.62 (1H, d, J ¼ 15, C5 H), 9.15 (1H, s, C2 H), 15.00 (1H, s, CONH).
MS m/z(%): 91.0 (100%), 145.0 (1.57%), 187.0 (1.07%), 188.0 (0.87%),
197.0 (1.17%), 203.0 (0.90%), 210.0 (0.44%), 253.0 (0.44%), 482.0
(0.44%).
141.61 (C2 0), 148.67 (C80a0), 148.85 (C5), 159.76 (C2), 163.24 (C7 ),
163.46 (C9 ), 176.38 (C4 ). MS m/z(%): 40.6 (100%), 91.0 (14.15%),
131.5 (5.68%), 143.7 (1.92%), 159.9 (1.84%), 173.5 (0.70%), 181.9
(1.36%), 182.9 (7.39%), 186.9 (0.84%), 198.2 (1.13%), 203.3 (2.15%),
209.0 (9.74%), 231.1 (1.34%), 246.3 (2.51%), 300.4 (0.90%), 315.5
(2.46%), 330.4 (1.74%), 410.2 (4.26%), 454.6 (1.28%), 544.1 (2.23%),
546.6 (2.23%).
0
0
4.2.12. N0-(5-Bromo-2-oxo-1-propylindolin-3-ylidene)-1-ethyl-1,4-
dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (6d)
Yield: 97%; m.p. 314 ꢀC(from DMF). IR nmax/cmꢁ11109.32 (CeBr),
1442.28 (NeN), 1472.23 (CeN), 1542.15 (C]N), 1608.34, 1680.70
(C]O), 2933.60, 2981.22 (CeH aliphatic), 3047.60 (CeH aromatic),
4.2.15. N0-(5-Bromo-1-hydroxymethyl-2-oxoindolin-3-ylidene)-1-
ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-
carbohydrazide (6g)
3446.84 (NeH). 1H NMR dH(CDCl3)0: 1.00 (3H, t,
J
¼
7.25,
N1CH2CH2CH3), 1.57 (3H, t, J ¼ 7.25, N1 CH2CH3), 1.75e1.80 (2H, m,
0
N1CH2CH2CH3), 2.71 (3H, s, C7 CH3), 3.79 (2H, t,
J
¼
7.5,
Yield: 75%; m.p. 315e318 ꢀC(charring, from EtOH). IR nmax/cmꢁ1
1111.70 (CeBr), 1253.95 (CeO), 1441.20 (NeN), 1465.56 (CeN),
1541.85 (C]N), 1609.19, 1684.10 (C]O amidic), 2939.91, 2987.53
(CeH aliphatic), 3047.62 (CeH aromatic), 3357.14 (OeH), 3452.38
(NeH). MS m/z(%): 132.0 (48.10%), 145.0 (16.20%), 160.0 (34.30%),
173.0 (10.00%), 182.0 (3.30%), 183.0 (6.20%), 187.0 (61.40%), 188.0
(97.10%), 198.0 (8.10%), 203.0 (2.90%), 215.0 (100%), 231.0 (12.40%),
425.0 (10.00%), 453.0 (5.20%).
0
N1CH2CH2CH3), 4.62 (2H, q, J1 ¼ 14.5, J2 ¼ 21.5, N1 CH2CH3), 6.78
0
(1H, d, J ¼ 8, C7H), 7.33 (1H, d, J ¼ 8, C6 H), 7.48 (1H, dd, J1 ¼ 2, J2 ¼ 2,
0
0
C6H), 8.05 (1H, s, C4H), 8.86 (1H, d, J ¼ 8.5, C5 H), 9.05 (1H, s, C2 H),
15.36 (1H0, s, CONH). 13C NMR dC (CDCl3): 11.37 (N1CH2CH2CH3),
0
15.27 (N1 CH2CH3), 20.91 (N1CH2CH2CH3), 25.15 (C7 CH3), 41.47
0
0
(N1CH2CH2CH3), 47.13 (N1 CH2CH3), 110.27 (C4), 111.96 (C5 ), 115.61
0
0
(C70), 120.62 (C6 ), 121.54 (C4a0), 122.380 (C6 ), 124.84 (C3a), 133.30
(C3 ), 135.87 (C7a), 137.02 (C3), 142.02 (C2 ), 148.66 (C8a0), 148.84 (C5),
0
0
0
159.72 (C2), 163.29 (C7 ), 163.45(C9 ), 176.38 (C4 ). MS m/z(%): 43.1
(100%), 133.2 (12.82%), 146.8 (1.55%), 160.0 (4.87%), 172.7 (1.21%),
182.4 (2.15%), 187.7 (0.48%), 188.9 (2.35%), 196.8 (3.35%), 203.2
(2.07%), 209.7 (4.64%), 215.1 (0.93%), 231.9 (0.86%), 246.0 (0.76%),
256.0 (6.25%), 266.3 (1.88%), 281.0 (2.65%), 410.7 (1.02%), 426.1
(1.09%), 455.3 (2.61%), 497.5 (2.45%).
4.3. Synthesis of Mannich bases 7(aec) and 8(aec)
Mixture of appropriate Schiff’s base 5a or 6a (0.5 mmol) and 40%
formaldehyde (0.02 g, 0.75 mmol) was stirred at RT in EtOH (20 ml).
Appropriate secondary amine (0.75 mmol) was added and stirring
was continued for overnight and the reaction progress checked by
TLC (DCM:MeOH 95:5 v/v). The solvent was concentrated and the
precipitate was filtrated and washed thoroughly with aqueous
ethanol.
4.2.13. N0-(1-Allyl-5-bromo-2-oxoindolin-3-ylidene)-1-ethyl-1,4-
dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (6e)
Yield: 92%; m.p. 309 ꢀC(from DCM). IR nmax/cmꢁ1: 916.82,
976.37, 1645.18 (CeH allyl), 1114.64 (CeBr), 1443.27 (NeN), 1474.15
(CeN), 1542.13 (C]N), 1609.47, 1679.86 (C]O amidic), 2935.56,
2983.18 (CeH aliphatic), 3071.42 (CeH aromatic), 3447.53 (NeH).
4.3.1. N0-(1-((Diethylamino)methyl)-2-oxoindolin-3-ylidene)-1-
ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-
carbohydrazide (7a)
1H NMR dH(CDCl3): 1.57 (3H, t, J ¼ 10, N1 CH2CH3), 2.71 (3H, s,
0
0
C7 CH3), 4.48 (2H, d, J ¼ 2.5, N1CH2CH]CH2), 4.61 (2H, q, J1 ¼ 9,
Yield: 51%; m.p. 380e385 ꢀC (charring, from EtOH). IR nmax/cmꢁ1
1440.63 (NeN), 1464.14 (CeN), 1505.53, 1540.30, 1576.47 (C]N),
1610.14, 1677.05 (C]O amidic), 1696.19 (C]O), 2885.59, 2933.15
(NeCH2eN), 2980.77 (CeH aliphatic), 3057.33 (CeH aromatic),
3339.77 (NeH). MS m/z(%): 57.0 (100%), 72.0 (8.80%), 86.9 (14.75%),
102.0 (20.60%), 103.0 (32.40%), 104.0 (57.40%), 118.0 (47.10%), 131.0
(48.50%), 132.0 (35.30%), 144.8 (1.96%), 160.0 (4.40%), 173.1 (1.33%),
187.0 (48.50%), 188.0 (41.20%), 203.0 (7.40%), 215.1 (3.08%), 218.1
(1.86%), 230.3 (0.42%), 231.3 (1.62%), 246.1 (0.32%), 331.0 (8.80%),
346.7 (0.59%), 375.0 (22.10%), 459.2 (0.09%), 460.0 (10.30%), 461.0
(4.40%).
0
J2 ¼ 9.5, N1 CH2CH3), 5.28 (2H, m, N1CH2CH]CH2), 5.80e5.90 (01H,
m, N1CH2CH]CH2), 6.78 (1H, d, J ¼ 7, C7H), 7.35 (1H, d, J ¼ 8, C60H),
7.46 (1H, d, J ¼0 7, C6H), 8.06 (1H, s, C4H), 8.86 (1H, d, J ¼ 7.5, C5 H),
9.05 (1H, s, C2 H), 15.38 (1H, s, CONH). 13C NMR dC (CDCl3): 15.28
0
0
(N10CH2CH3), 25.16 (C7 CH3), 42.10 (N1CH2CH]CH2), 47.15
0
(N1 CH2CH3), 110.96 (C4), 0111.91 (C5 ), 115.89 (C7), 118.38
(N1CH2CH]CH2), 120.61 (C6 ), 121.59 (C4a0), 122.33 (C6), 124.78
0
(C3a),130.82 (N1CH2CH]CH2),133.31 (C3 ), 135.60 (C7a), 136.98 (C3),
141.67 (C20), 148.66 (C8a0), 148.86 (C5), 159.41 (C2), 163.29 (C7 ),
0
0
0
163.49 (C9 ), 176.39 (C4 ). MS m/z(%): 40.9 (100%), 130.7 (0.75%),
145.8 (9.38%), 160.0 (0.73%), 173.3 (1.80%), 181.5 (4.35%), 183.6
(4.31%), 196.7 (0.75%), 203.0 (1.07%), 211.5 (4.11%), 213.7 (1.36%),
229.7 (2.94%), 244.5 (1.80%), 251.6 (2.26%), 264.9 (7.54%), 280.5
(12.88%), 410.8 (1.42%), 453.5 (2.76%), 492.6 (1.92%), 493.8 (0.73%),
495.7 (1.90%), 496.8 (0.84%).
4.3.2. 1-Ethyl-1,4-dihydro-7-methyl-N0-(1-((4-methylpiperazin-1-
yl)methyl)-2-oxoindolin-3-ylidene)-4-oxo-1,8-naphthyridine-3-
carbohydrazide (7b)
Yield: 59%; m.p. > 400 ꢀC(from EtOH). IR nmax/cmꢁ1 1440.07
(NeN), 1469.00 (CeN), 1505.69, 1540.21, 1576.22 (C]N),
1610.00, 1676.66 (C]O amidic), 1696.29 (C]O), 2861.54,
2932.97 (NeCH2eN), 2980.59 (CeH aliphatic), 3056.63 (CeH
aromatic), 3338.77 (NeH). MS m/z(%): 103.0 (36.80%), 104.0
(73.50%), 118.0 (15.40%), 131.0 (42.60%), 132.0 (55.90%), 145.0
(22.10%), 160.0 (31.60%), 173.0 (13.20%), 187.0 (95.60%), 188.0
(95.60%), 215.0 (100%), 231.0 (0.70%), 347.0 (50.00%), 375.0
(19.10%), 486.5 (0.02%), 487.4 (0.15%), 488.3 (0.01%), 489.8
(0.06%).
4.2.14. N0-(1-Benzyl-5-bromo-2-oxoindolin-3-ylidene)-1-ethyl-1,4-
dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazide (6f)
Yield: 99%; m.p. 323 ꢀC(from DCM). IR nmax/cmꢁ1: 1115.18
(CeBr), 1441.62 (NeN), 1472.18 (CeN), 1541.43 (C]N), 1608.23,
1683.65 (C]O amidic), 2869.64, 2934.07 (CeH aliphatic), 3047.62
(CeH aromatic), 3447.36 (NeH). 1H NMR dH(CDCl3): 1.57 (3H, bs,
0
0
0
N1 CH2CH3), 2.70 (3H, bs, C7 CH3), 4.61 (2H, bs, N1 CH2CH3), 5.04
0
(2H, bs, N1CH2ph), 6.61 (1H, bs, C7H), 7.20e7.50 (7H, m, C6 H, C6H

T. Aboul-Fadl et al. / European Journal of Medicinal Chemistry 45 (2010) 4578e4586
4585
4.3.3. 1-Ethyl-1,4-dihydro-7-methyl-4-oxo-N0-(2-oxo-1-
((piperidin-1-yl)methyl)indolin-3-ylidene)-1,8-naphthyridine-3-
carbohydrazide (7c)
for the active compounds were done to give 100, 50, 25, 12.5, 6.25
and up to 0.625 g/ml. The agar and the compound solution were
m
mixed thoroughly and the mixture was poured into Petriedishes on
a level surface to result in an agar depth of 3e4 mm and allowed to
harden. The incula were prepared by growing overnight culture in
MullereHinton broth. The cultures were diluted 1:100. Test
organisms were streaked in a radial pattern and plates were incu-
bated at 35 ꢀC for 48 h. Control experiment consisted of the tested
TB strains, DMSO and the growing media were treated in the same
manner. Complete suspension of growth was observed prior to
declaring the compound to be active. Results are given in Table 1.
Yield: 59%; m.p. > 400 ꢀC (from EtOH). IR nmax/cmꢁ1: 1440.24
(NeN), 1464.02 (CeN), 1505.60, 1540.25, 1576.30 (C]N), 1610.02,
1676.80 (C]O amidic), 1696.19 (C]O), 2892.92, 2940.54
(NeCH2eN), 2964.35 (CeH aliphatic), 3056.59 (CeH aromatic),
3338.90 (NeH). MS m/z(%): 84.0 (3.20%), 98.1 (1.69%), 103.0
(18.50%), 104.0 (23.30%), 113.9 (1.49%), 118.0 (5.70%), 131.0 (20.70%),
132.0 (19.70%), 145.0 (5.50%), 160.0 (10.40%), 173.0 (4.10%), 187.0
(35.90%), 188.0 (53.00%), 203.0 (1.40%), 215.0 (100%), 230.9 (0.39%),
231.0 (4.30%), 243.1 (0.18%), 247.0 (0.70%), 258.0 (0.34%), 331.0
(0.70%), 347.0 (32.80%), 375.0 (10.50%), 471.3 (0.05%), 472.4 (0.11%),
473.9 (0.12%).
4.5. Pharmacophore building
The procedures followed for pharmacophore building explained
in the following points [21].
4.3.4. N0-(1-((Diethylamino)methyl)-5-bromo-2-oxoindolin-3-
ylidene)-1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-
carbohydrazide (8a)
1. Flexible alignment operated for the 10 compounds as a training
set by the following steps: a. The selected compounds were
built using the builder interface of the MOE program; b. Open
the Flexible Alignment panel. The Flexible mode was selected
as it enables all-atom flexibility (and hence conformational
search) during the generation of molecular alignments; c. The
output of flexible alignment contain the following data:
Yield: 75%; m.p. 398e400 ꢀC (charring, from EtOH). IR nmax
/
cmꢁ1: 1111.50 (CeBr), 1441.83 (NeN), 1465.92 (CeN), 1542.86 (C]
N), 1608.49, 1664.23 (C]O amidic), 1685.11 (C]O), 2833.33,
2880.95 (NeCH2eN), 2928.57 (CeH aliphatic), 3029.73, 3101.16,
3148.78 (CeH aromatic), 3447.19 (NeH). MS m/z(%): 72.0 (6.30%),
85.0 (3.10%), 102.0 (16.30%), 132.0 (31.30%), 145.0 (9.40%), 160.0
(33.10%), 173.0 (3.10%), 187.0 (49.40%), 188.0 (81.30%), 196.0
(11.30%), 215.0 (100%), 231.0 (15.60%), 425.0 (13.10%), 538.4 (0.51%),
539.5 (1.28%).
U The average strain energy of the molecules in the alignment in
kcal/mol.
F The total mutual similarity score of the configuration.
S The alignment score of the configuration. Lower values are
intended to indicate better alignments.
4.3.5. N0-(5-Bromo-1-((4-methylpiperazin-1-yl)methyl)-2-
oxoindolin-3-ylidene)-1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-
naphthyridine-3-carbohydrazide (8b)
Yield: 52%; m.p. > 400 ꢀC(from EtOH). IR nmax/cmꢁ1: 1110.75
(CeBr), 1440.87 (NeN), 1464.68 (CeN), 1543.07 (C]N), 1607.82,
1664.29 (C]O amidic), 1688.10 (C]O), 2837.73, 2861.54
(NeCH2eN), 2909.16, 2956.78 (CeH aliphatic), 3047.62, 3119.05,
3147.64 (CeH aromatic), 3474.35 (NeH). MS m/z(%): 43.9 (100%),
99.0 (2.18%), 113.1 (1.35%), 129.0 (2.96%), 132.0 (13.10%), 145.0
(8.30%), 160.0 (12.90%), 173.0 (5.00%), 181.0 (2.20%), 183.0 (1.40%),
187.0 (44.70%), 188.0 (48.40%), 196.0 (3.00%), 203.0 (2.90%), 210.0
(1.30%), 215.0 (62.86%), 230.1 (0.23%), 231.0 (4.30%), 247.0 (0.40%),
323.8 (0.03%), 337.3 (0.04%), 351.4 (0.05%), 412.0 (0.90%), 426.4
(2.30%), 453.0 (2.80%), 566.2 (0.01%), 567.0 (0.06%), 568.2 (0.05%).
2. Copy the aligned structures having the lowest S value to MOE
window.
3. Create a pharmacophore query for the aligned training set
molecules using the Pharmacophore Query Editor.
4. The generated model is subjected to the systemic test set
conformational search using the Pharmacophore Search.
5. The program generate annotations for all ligand conformations
in the test set database using the Pharmacophore Preprocessor
by the
currently selected
PCH
(PolarityeChargee
Hydrophobicity) pharmacophore scheme.
6. Modify the query using consensus query method and search
the same database again.
7. The program expresses the degree of mapping of a given compound
to a generated hypothetical model in term of rmsd value.
4.3.6. N0-(5-Bromo-2-oxo-1-((piperidin-1-yl)methyl)indolin-3-
ylidene)-1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-
carbohydrazide (8c)
Yield: 62%; m.p. > 400 ꢀC(from EtOH). IR nmax/cmꢁ1: 1111.40
(CeBr), 1441.42 (NeN), 1465.81 (CeN), 1543.38 (C]N), 1608.78,
1664.28 (C]O amidic), 1688.09 (C]O), 2813.70, 2861.32
(NeCH2eN), 2932.75, 2980.37 (CeH aliphatic), 3071.43, 3119.05,
3149.30 (CeH aromatic), 3461.68 (NeH). MS m/z(%): 85.0 (2.30%),
99.0 (2.50%), 115.0 (14.10%), 132.0 (27.00%), 145.0 (10.40%), 160.0
(27.90%), 173.0 (8.20%), 182.0 (3.10%), 183.0 (2.00%), 187.0 (45.50%),
188.0 (62.30%), 197.0 (2.00%), 203.0 (3.90%), 210.0 (2.30%), 215.0
(100%), 230.0 (1.40%), 231.0 (4.10%), 246.0 (2.00%), 338.0 (1.40%),
426.0 (3.50%), 454.0 (3.70%).
Results are shown in Table 3.
Acknowledgements
This work was supported in part by a grant from King Abdulaziz
city for Science and Technology (KACST) grant no. AT-17-091.
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