Novel series of N-acylhydrazone based on acridone: Synthesis, conformational and theoretical studies

Article abstract of DOI:10.1016/j.molstruc.2020.129079

In this work, novel N-acylhydrazone derivatives from acridone have been synthesized by condensation of 9-oxoacridin-10(9H)-yl)acetohydrazide with various aldehyde and ketone. The structures of these novel compounds were elucidated by ¹H NMR, ¹³C NMR, IR and mass spectroscopy. The NMR data shows two conformations (E, trans and E, cis) due to N–C(O) bond rotation, the conformations of synthesized compounds have been investigated by different NMR methods. The rotational barriers around N–C(O) bond for compound 5a was measured in DMSO using dynamic NMR spectroscopy, this result was confirmed by DFT calculations at B3LYP/6–31 G (d) level in DMSO.

Full text of DOI:10.1016/j.molstruc.2020.129079

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Novel series of N-acylhydrazone based on acridone: synthesis,
conformational and theoretical studies
Mohammed Aarjane , Siham Slassi , Amina Amine
PII:
S0022-2860(20)31401-0
DOI:
Reference:
https://doi.org/10.1016/j.molstruc.2020.129079
MOLSTR 129079
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10 July 2020
12 August 2020
Please cite this article as: Mohammed Aarjane , Siham Slassi , Amina Amine , Novel series of N-
acylhydrazone based on acridone: synthesis, conformational and theoretical studies, Journal of Molec-
ular Structure (2020), doi: https://doi.org/10.1016/j.molstruc.2020.129079
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HIGHLIGHTS
 Novel N-acylhydrazone compounds having acridone moiety were synthesized.
 Structures and physical properties of the hybrid compounds were elucidated.
 The NMR data shows two conformations (E, trans and E, cis) due to N–C(O) bond
rotation
 Conformational analysis were made by means of DFT calculations.

Novel series of N-acylhydrazone based on acridone: synthesis,
conformational and theoretical studies
Mohammed Aarjane1*, Siham Slassi1, Amina Amine1
a Laboratory of Chemistry/Biology Applied to the Environment, Faculty of Science,
University Moulay Ismail, BP 11201 Zitoune, Meknes, Morocco.
*Corresponding author: e-mail: aarjane.mohammed@gmail.com
Abstract
In this work, novel N-acylhydrazone derivatives from acridone have been synthesized
by condensation of 9-oxoacridin-10(9H)-yl)acetohydrazide with various aldehyde and ketone.
1
13
The structures of these novel compounds were elucidated by H NMR, C NMR, IR and
mass spectroscopy. The NMR data shows two conformations (E, trans and E, cis) due to N–
C(O) bond rotation, the conformations of synthesized compounds have been investigated by
different NMR methods. The rotational barriers around N-C(O) bond for compound 5a was
measured in DMSO using dynamic NMR spectroscopy, this result was confirmed by DFT
calculations at B3LYP/6-31G (d) level in DMSO.
Keywords: Acylhydrazone; Acridone; Conformation; DNMR spectroscopy; Theoretical
study.
Introduction
Acridones are well known as chemical intermediates used in the preparation of many
alkaloids such as Acronycine, Cystodytin A and Pyridoacridine [1]. Some of the acridone
derivatives are known for many years for their biological activities such as antitumor [2],
antiviral [3], antimalarial [4] and antimicrobial bioactivity [5,6]. Several methods are reported
for the synthesis of the acridone ring, among them Ullman reaction which was considered as
the most efficient [7]. On the other hand acylhydrazone compounds are an important chemical
intermediates used in the synthesis of many heterocyclic skeletons and they are also
considered as interesting ligands for metal complexes formation [8], some acylhydrazone
derivatives are used as highly selective and sensitive sensor of several metals [9,10].
Acylhydrazone derivatives are reported for their biological activities such as antibacterial
[11,12], anticonvulsant [13], anti-inflammatory [14,15], antimalarial [16–18] and

antileishmanial activities [19]. The versatility of acylhydrazones is related to the presence of
geometrical isomers Z and E at the C=N bond of the fragment acylhydrazone, as well as cis /
trans at the amide function [20–24]. The NMR spectroscopy is generally used as a powerful
tool to study the isomerization of acylhydrazone in solution [25]. In spite of extensive
conformational NMR studies of acylhydrazone stereochemistry. The conformation studies of
N-acylhydrazone derivatives from acridone have not yet been published. In this work, we
report detailed NMR studies to determine the stereochemistry and conformation of novel N-
acylhydrazone derivatives from acridone. On the other hand, one of the promising directions,
in our opinion to develop new pharmacological compounds is the introduction of
acylhydrazone groups into the acridone skeleton. On the basis of the pharmacological activity
profiles of acylhydrazones and acridones, we focused our work on the preparation of novel
acridone bearing acylhydrazone unite.
Result and discussion
Synthesis
The novel acylhydrazones based on acridone were synthesized via a three-step
reaction (Scheme 1). The first step was the preparation of acridone nucleus via Ullmann
condensation reaction of o-bromobenzoic acid with aniline in the presence of potassium
carbonate as base and copper in isoamyl alcohol at reflux to produce 2-arylamino benzoic
acids (1) [26] which was then cyclized with polyphosphoric acid in a water bath at 90 °C for
four hours to give acridone (2) in good yield 78%.
The second step was the N-alkylation of acridone ring, the tautomerism of acridone
nucleus contributes to the low basicity of the nitrogen, so the N-alkylation of the acridone
nucleus is a relatively difficult reaction. However, the use of a strong base such as potassium
carbonate in an anhydrous medium is required for the deprotonation of acridone. The
preparation of (9-oxo-9,10-dihydroacridin‐10 yl)acetohydrazide (4) was achieved by N-
alkylation of acridone using solid-liquid phase transfer catalyst. Stirring acridone (2) with
ethyl 2-bromoacetate in the presence of anhydrous potassium carbonate as base and tetra-n-
butylammonium bromide (TBAB) as catalyst in DMF at 70 °C give ethyl 2-(9-oxoacridin-
10(9H)-yl)acetate (3). Then the compound (3) was reacted with hydrazine hydrate in DMSO
to produce (9-oxo-9,10-dihydroacridin‐10 yl)acetohydrazide (4) in good yield.
The third step was the condensation reaction of (9-oxo-9,10-dihydroacridin‐10
yl)acetohydrazide (4) with variously substituted aldehydes and ketone, the condensation

reaction was carried out in the presence of a few drops of acetic acid as catalyst, the reaction
was conducted in reflux ethanol for 3h, then the mixture was filtered and purified by
recrystallization in DMF, the novel acylhydrazones (5a-k) were obtained in good yields
(Scheme 1).
Scheme 1: Synthesis of N-acylhydrazone derivatives from acridone
Characterization of compounds (5a-k) and their conformational studies
1
13
The structure of the products was determined by FT-IR, H-NMR, C-NMR IR and
mass spectral data. In FTIR spectra of synthesized compound (5a-k) we observed the absence
of the vibration bonds of amine (NH2) group in the region of 3226 cm-1 confirmed the
formation of compounds. These compounds showed characteristic bands in the region of
1680-1638 cm-1 due to presence of carbonyl group of the acridone ring and the hydrazone
function, and bands corresponding to the stretching vibrations of the imine in the region of
1600-1611 cm-1. Compounds 5b, 5c and 5h showed characteristic FTIR bands at 3500 cm-1
due to O-H groups

NMR spectra of the products (5a-h) are carried out in DMSO-d6 in order to shade
more light about the structure of the produced novel compounds especially the presence of
1
conformational isomers. In H-NMR spectra of the compounds (5a-h) were observed the
presence of two sets of resonance signals for amide, methylene and imine protons, which
resulted from the interconversion and equilibrium between rotamers (and/or configurational
isomers) of each compound in solution [27,28]. It is known that N-acylhydrazones may exist
as geometrical isomers in respect to the C=N double bonds ((E/Z)-configurational isomers)
and as (trans/cis)-rotamers caused by the inversion of amide bonds (Figure 1). Though, the
E/Z isomerization was not observed since these N-acylhydrazones exist completely in the (E)-
configuration about the C=N bond due to steric hindrance on the imine bond [29], which was
supported by means of relative free energy calculations in a former report [30].
Figure 1: Different conformations and configurations in acylhydrazone derivatives
Regarding the novel N-acylhydrazones (5a-h), the HC=N protons appeared as
expected as two separate singlets in the region δ 8.50-8.07 ppm. Also the methylene protons
were observed as two singlets in the region δ 5.80-5.17 ppm. The amide inversion also made
the CONH proton present as two broad singlets in the range δ 12.10-11.77ppm. On the basis
of the amide conformer assignments of the N-acylhydrazones reported in the literature
[27,31], the signal of amide protons most deshielded was related to the E, cis conformer and
the most shielded, to the E, trans conformer. Concerning compound 5k we observed the
presence of splitting signals of methylene (5.59 and 5.36 ppm) and amide protons (10.77 and
10.66 ppm), while the isomerization around the double bond (C=N) is degenerated. These

results can be explained by the existence of cis/trans-amide conformers only. In 13C NMR,
the spectra also show two sets of signals to 47.11-48.50 ppm and 168.94-163.38 ppm
corresponding to the signal of the methylene (-N-CH2-) and amide (-NHCO), respectively,
while the signal of the imine (C=N) to 149.85-145.30 ppm appears as a single signal.
1
The H NMR spectrum of the compound 5a (Figure 2) shows two signals at 5.80
(75%, E, trans conformation) and 5.35 ppm (25%, E, cis conformation) attributable to the
protons of the methylene (NCH2). Approximately the same abundance is found in the case of
the imine proton (N=CH) signals at δ 8.33 ppm (25%, E, cis conformation) and δ 8.18 ppm
(75%, E, trans conformation) and for amide proton (CONH) at δ 12.01 ppm (23%, E, cis
conformation) and 11.97 ppm (77%, E, trans conformation)
Figure 2: 1H NMR of compound 5a (DMSO-d6)
The signals intensities of the methylene, imine, and amide protons allowed us to
measure the ratio of cis/trans-amide conformers of 5a-h, the percentage of cis/trans
conformers in DMSO-d6 are summarized in Table 1.
Table 1: E,cis/trans conformer ratios in DMSO-d6
compound
E, cis (%)
E, trans (%)

27
41
26
24
26
27
28
27
33
73
59
74
76
74
73
72
73
67
5a
5b
5c
5d
5e
5f
5g
5h
5k
N–C(O) Rotational Barrier
In order to study the cis/trans isomerization around the N–C(O) bond of the novel
acylhydrazone, dynamic NMR experiments study was carried out in DMSO-d6 to evaluate
rate constants of the cis/trans amide equilibrium and estimate the energy barriers of the
1
rotation. As examples, the variable-temperature H NMR spectra of compound 5a in DMSO
are presented in Figure 3. The spectrum of compounds 5a show two sets of signals due to the
1
presence of cis/trans-amide conformers at 298 K, with increasing temperature the H NMR
spectra of compound 5a are simplified and at a temperature above 348 K only unique signals
are observed for the protons of the methylene (NCH2) and amide (CONH). The rate constants
kc at the coalescence temperature was calculated using the Gutowsky equation Eqn (1) [32]
and free energy of activation for the rotation G# was calculated at the coalescence
temperature Tc= 348 K, using the Eyring equation Eqn (2) [33].
kc = (π x ∆) / 2) ½
Eqn 1
Eqn 2
∆G ≠ = 19.14 Tc (10.32 + log Tc / kc) 10-3
1
In the H NMR spectrum (Fig. 3, 298 K) of compound 5a, the chemical shift
difference for the two resonance signals of amide proton is 16 Hz, corresponding to G#=
75.2 kJ/mol at Tc= 348 K. Hence the activation barriers found for compound 5a is very close
to literature data for exchange between rotamers of similar N–C(O) bonds [28,34].

Figure 3: a) NCH2 and b) CONH regions of 1H NMR spectra of compound 5a in DMSO d6 at
variable temperatures.
Computational methods
In order to confirm the experimentally determined barrier to rotation of the CONH
group, theoretical calculations were carried out with the Gaussian 09 package [35]. Molecular
geometries obtained through theoretical methods by the optimization of the synthesized
compounds using the B3LYP/6-31G (d) level in DMSO are useful to describe the stability of
E, trans and E, cis conformation. For further investigation on the conformational features of
compounds 5a-h, conformational analysis was performed to determine the stable conformers
in DMSO, via sampling points on the potential energy surface. Relaxed potential energy scan
was performed on the dihedral angle O28-C27-N29-N31 around an idealized rotatable bond,
which is scanned from −180° to 180° in steps of 20°, while all of the other geometrical
parameters have been simultaneously relaxed. The stationary points were confirmed by the
frequency analysis as minima with all real frequencies and with no imaginary frequency
implying no transition state. Compound 5a was used as a model in this study, as shown in
Figure 4, three minimum energy conformers were found at about 0.1°, -179.9° and 180°. Two
minimum geometries are equal and detected at  values 180.0° and -179.9°, correspond to the
E, trans conformer. The other minimum geometries observed at 0.1° correspond to the
geometry of conformer E, cis. The difference of energy between E, trans and E, cis
conformers is only 1.1 kcal/mol. Two maximum points are detected at  values 90.1° and -
89.8°, correspond to the transition geometries between E, trans and E, cis conformers. The
energies of the two transition states (90.1° and -89.8°) are also very close each other. The
barriers to the rotation is 73–74 kJ/mol (at 298 K). These results are in agreement with the

barrier height of 75 kJ/mol deduced from analysis of the temperature dependence of 1H NMR
spectra and previous data on N–C(O) bonds rotation in acylhydrazone [34].
Figure 4: Potential energy surface scan of compound 5a with dihedral angle O28-C27-N29-N31.
Optimized geometries of compounds 5a-k (E, trans and E, cis) showed that the
acridone nucleus is not completely planar; it is a slight bend of approximately 1.8° relative to
the axis that passes through the keto and the nitrogen of the amino group. In addition, the
value of dihedral angle between acylhydrazone group and phenyl ring (178°-179°), indicate
the planarity between the acylhydrazone group and the phenyl ring. Moreover acylhydrazone
group in E, trans conformation of compounds 5a-h show perpendicular orientation for
acridone nucleus and it is quite obvious from their corresponding interplanar angle of about
89°, whereas in the case of conformations E, cis the interplanar angle is between 37°-52°
(Figure S1-9).

Figure 5: Optimized structures of the E, trans and E, cis conformers of 5a
According to the computational results, two minimum energy conformers were
obtained at about 0° and 180°, corresponding to the E, trans and E, cis conformers. The
comparison of the energies of the compounds 5a-h (Table 2), shows that E, trans conformer is
more stable than E, cis conformer, with energy differences between 2.17 and 8.87 kcal/mol.
Table 2: The cis/trans amide conformer energies for compounds 5a-h in DMSO.
E (a.u)
E (Kcal/mol)
trans
cis
-1162.977
-1238.236
-1238.190
-1622.579
-1277.478
-1296.929
-1360.241
-1352.648
-1162.975
-1238.229
-1238.187
-1622.567
-1277.466
-1296.915
-1360.227
-1352.638
1.16
4.17
2.17
7.53
7.35
8.78
8.87
6.27
5a
5b
5c
5d
5e
5f
5g
5h
Theoretical NMR spectra
In order to confirm the proposed experimental structures of the synthesized
compounds, NMR spectra were simulated. The optimized structures of compounds 5a-k (E,
trans and E, cis) are used to calculate the NMR spectra at DFT (B3LYP) /6-31G(d) level
1
13
using the GIAO method with IEFPCM/DMSO solution. The theoretical H and C NMR
chemical shift values have been compared with the experimental data in Table 3. Theoretical
1H NMR spectra of conformers E, trans and E, cis of compounds (5a-k) in DMSO, displays a
difference in chemical shift at the level of the methylene, imine and amide protons. The

signals of methylene protons (NCH ) for E,trans conformers were observed between 5.13-
2
4.70 ppm, While the signals of conformers E, cis were observed between 4.90-4.36 ppm.
Similarly the signals of imine protons (HC=N) for E, cis conformers resonate between 7.69-
7.00 ppm are shielded with respect to the signals of the conformers E, trans. Regarding the
amide protons (NHCO), for conformers E, cis, the signals are deshielded with respect to the
signals of the conformers E, trans. The results of theoretical 1H NMR study are in agreement
with the experimental NMR data that show splitting of signals for amide (CONH), methylene
(NCH
) and imine (N=CH) protons. The same results are observed in 13C NMR, the
2
conformers E, trans and E, cis displays a difference in chemical shift at the level of the
13
methylene and amide carbons. According to the C NMR spectra, the two signals between
47.6-47.1 ppm and 48.7-47.4 ppm are undoubtedly assigned to the methylene carbons of the
conformers E, trans and E, cis, respectively, which is in agreement with predicted values at
49.0-47.2 ppm and 50.1-46.2 ppm, respectively. The amide carbons of the conformers E,
trans and E, cis were observed between 168.9-168 ppm and 166.5-163.4 ppm, respectively in
agreement with estimated values using B3LYP method.

Table 3: Theoretical and experimental 1H and 13C chemical shifts (with respect to TMS, all
values in ppm) for compounds 5a-k using B3LYP/6‒31G (d) level of theory.
Experimental 1H
chemical shifts
Theoretical 1H
chemical shifts
Experimental 13C
chemical shifts
Theoretical 13C
chemical shifts
NCH
N=CH
trans
cis
NH
trans
cis
NCH2 N=CH
NH
trans
cis
NCH2
trans
cis
CONH
trans
cis
NCH2
trans
cis
CONH
trans
cis
2
trans
cis
trans
cis
trans
cis
5.80
5.35
8.18
8.33
11.96
12.01
4.82
4.64
7.44
7.48
9.73
10.07
47.6
48.5
168.9
164.3
47.9
48.6
178
170.7
5a
5b
5.71
5.32
8.40
8.50
11.84
12.15
5.12
4.80
7.72
7.52
9.68
10.23
47.6
48.4
168.5
164.2
48.1
49.1
177.4
171.6
5.47
5.31
5.79
5.17
5.71
5.28
5.72
5.30
5.84
5.38
8.07
8.20
8.16
8.31
8.07
8.22
8.03
8.15
8.26
8.43
11.77
11.82
12.03
12.10
11.78
11.81
11.68
11.71
12.24
12.30
4.74
4.36
4.92
4.74
5.13
4.90
4.71
4.38
4.76
4.57
7.29
7.00
7.54
7.57
7.82
7.69
7.13
7.22
7.58
7.50
9.8
10.1
9.93
10.19
9.78
10.25
9.31
9.79
9.67
10.80
47.1
47.9
47.2
47.4
47.6
48.5
47.1
48.0
47.2
48.3
168.0
163.3
168.5
166.5
168.6
164.0
49.0
49.9
48.3
47.3
48.2
48.9
48.7
46.9
50.1
45.9
177.3
169.0
177
172.7
176.4
171.5
176.1
168.2
177.7
168.8
5c
5d
5e
5f
167.7
168.8
163.7
5g
5.76
5.32
8.05
8.19
11.82
11.78
4.70
4.57
7.23
7.29
9.59
10.07
47.2
48.7
168.0
163.4
49.1
47.5
178
168
5h
5k
5.59
5.36
10.77
10.66
4.89
4.46
9.56
9.73
47.2
47.5
168.3
163.4
47.2
46.5
171.4
169.3
-
-
Conclusion
In this study, novel N-acylhydrazone derivatives from acridone (5a-k) were
synthesized by using an efficient and simple procedure. The structures of the compounds (5a-
1
13
1
k) were confirmed by H NMR, C NMR, IR and mass spectroscopy data. In the H NMR
13
and C NMR spectra, two sets of signals were observed, which suggests that the compounds
(5a-k) exists in two conformations (E, trans and E, cis). The results of dynamic NMR
spectroscopy show that rotation around the N—CO bond in compound 5a generate two
rotameric forms (E, trans and E, cis) separated by a free energy of activation barrier of 75
kJ/mol, this result was confirmed by DFT calculations at B3LYP/6-31G (d) level in DMSO.
Experimental Section
Materials

All materials were purchased from commercial suppliers. IR spectra were recorded
using JASCO FT-IR 4100 spectrophotometer. Mass spectrometric measurements were
1
13
recorded using SHIMADZU 8040 LC/MS/MS. The H, C NMR spectra was recorded with
Bruker Avance 300 at 25°C.
Synthesis
Synthesis of acridone (2)
A mixture of aniline (1.13 g, 14 mmol), o-bromobenzoic acid (2 g, 10 mmol), anhydrous
potassium carbonate (1.64 g, 12 mmol), 0.2 g of copper powder and 0.08 g of copper oxide
was refluxed for 4h in 20 ml of amyl alcohol. The amyl alcohol was evaporated then poured
into (100 ml) hot water, cooled to room temperature, acidification with HCl lead to (1) as a
white precipitate which was then recrystallized from ethanol. The N-phenylantranilic acid (2g,
9.4 mmol) was taken in 7 ml of concentrated sulfuric acid and heated on water bath for 3 h.
Reaction mixture was added to hot water and the resulting precipitates were filtered to get
acridone. The sample of acridone 2 was recrystallized from acetic acid.
1
Yellow solide, yield 78%, m.p. > 330 C. IR (KBr) 3275, 3084, 1640, 1570 cm-1. H NMR
(300 MHz, DMSO-d6, 25°C, TMS): 11.74 (s, 1H, NH), 8.23 (dd, J = 8.1, 1.2 Hz, 2H, H1-H8),
7.70 (td, J = 8.4, 1.5 Hz, 2H, H3-H6), 7.53 (d, J= 8.1 Hz, 2H, H4-H5), 7.23 (td, J = 8.4, 1.5 Hz,
13
2H, H2-H7). C NMR (75 MHz, DMSO-d6, 25°C, TMS): 177.29, 141.35, 133.94, 126.46,
121.49, 120.91, 117.80.
ethyl 2-(9-oxoacridin-10(9H)-yl)acetate (3)
To a mixture of acridone 2 (1g, 5 mmol) and sodium hydride (90 mg, 7.2 mmol) in DMF (5
ml), ethyl 2-bromoacetate (1.2g, 7.2 mmol) was added dropwise and the mixture was stirred
at 60°C for 3h. After that, it was poured into crushed ice and the white yellow formed
precipitate was recrystallized from ethanol-DMF.
Yellow solide, yield 75%, m.p.= 187 °C. IR (KBr) 3107, 2984, 2932, 1751, 1631, 1594, 1495
1H NMR (300 MHz, DMSO-d6, 25°C, TMS): 8.36 (dd, J = 8.1, 1.5 Hz,2H, H1-H8), 7,95 (d,
J= 8,7 Hz, 2H, H4, H5), 7.80 (td,J= 15.6, 6.9 1.5 Hz, 2H, H3, H6), 7.33 (t, J = 7.5 Hz, 2H,
13
H2,H7), 5.75 (s, 2H, CH2), 4,33 (q, J= 7.2 Hz, 2H, CH2), 1,14 (t, J= 7.2 Hz, 3H,CH3). C
NMR (75 MHz, DMSO-d6, 25°C, TMS):177.07, 168.64, 143.01, 142.23, 134.65, 127.13,
122.20, 122.00, 116.74, 61.89, 55.66, 15.12.
Synthesis of (9-oxo-9,10-dihydroacridin‐10‐yl)acetohydrazide (4)
To the compound 3 (1.12g, 4 mmol), dissolved in DMSO (2 mL), was added hydrazine
monohydrate (8 ml) and this mixture was refluxed for 24 hrs. Then the solvent was eliminated

by evaporation and the obtained product was purified using recrystallization from DMF-
ethanol.
1
Yellow solide yield: 76%; m.p> 300°C; IR (KBr) 3320 , 3084 , 1670, 1640, 1570 cm-1; H
NMR (300 MHz, DMSO-d6, 25°C, TMS): 9.55 (s, 1H, NH), 8.34 (dd, J 8.1 Hz, 1.5 Hz, 2H),
7.80 (m, 2H), 7.62 (d, J= 8.1Hz, 2H), 7.34 (td, 2H, J = 8.4, 1.5 Hz, 2H), 5.13 (s, 2H, CH2),
4.35 (s, 2H, NH2). 13C NMR (300 MHz, DMSO-d
126.98, 122.15, 121.89, 116.42 and 47.98.
6) δ (ppm): 177.23, 167.00, 142.98, 134.45,
Synthesis of N-acylhydrazones derivatives from acridone (5a-k)
An equimolar mixture of 2-(9-oxoacridin-10(9H)-yl)acetohydrazide 3 (0.1g, 4mmol) and
aldehyde or ketone (4mmol) was refluxed in ethanol for 3 hrs. The reaction mixture was
filtered and the obtained solid was dried then recrystallized from a mixture of DMF and
ethanol.
N-benzylidene-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5a)
Yellow solid; yield: 86 %, mp > 300 °C. IR (KBr): 3226, 3070, 2984, 1680, 1640, 1605, 1495
1
cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 12.00 (s, 1H, NH, 27%), 11.95 (s, 1H,
NH, 73%), 8.40 (dd, J = 8.0, 1.7 Hz, 2H), 8.32 (s, 1H, N=CH, 25%), 8.17 (s, 1H, N=CH,
75%), 7.84 – 7.65 (m, 6H), 7-52-7.45 (m, 3H), 7.39–7.34 (m, 2H), 5.79 (s, 2H, CH2, 73%),
5.34 (s, 2H, CH2, 27%). 13C NMR (75 MHz, DMSO-d6, 25°C, TMS): 177.22, 168.94, 164.34,
147.99, 144.87 142.98, 142.90, 134.63, 134.47, 130.59, 129.30, 127.61, 127.20, 122.09,
122.03, 121.90, 116.39, 48.50, 47.67. MS (ESI) for C22H17N3O2 [M + 1]+, calcd: 356,12,
found: 356.13.
N-(2-hydroxybenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5b)
Yellow solid; yield: 74 %, mp > 300 °C. IR (KBr): 3390, 3227, 3084, 2967, 1680, 1635,
1
1602, 1595, 1498 cm-1. H NMR (300 MHz, DMSO-d6J = 8.0, 1.7 Hz, 2H), 8.22 (s, 1H,
CH=N, 41%), 8.07 (s, 1H, CH=N, 59%), 7.83 (ddd, J = 8.7, 6.9, 1.7 Hz, 2H), 7.71 – 7.66 (m,
4H), 7.40 – 7.34 (m, 2H), 6.88-6.83 (m, 2H), 5.71 (s, 2H, CH2, 59%), 5.28 (s, 2H, CH2,
13
41%). C NMR (75 MHz, DMSO-d6, 25°C, TMS): 177.22, 168.63, 164.01, 161.23, 147.23
144.54, 142.61, 142.53, 134.14, 128.86, 126.51, 124.99, 124.92, 121.53, 121.40, 114.89,
114.67, 48.51, 47.56. MS (ESI) for C22H17N3O3 [M + 1]+, calcd: 372,13, found: 372.13
N-(4-hydroxybenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5c)
White solid; yield: 88 %, mp > 300 °C. IR (KBr): 3368, 3226, 3081, 2980, 1685, 1631, 1610,
1
1596, 1497 cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 11.83 (s, 1H, NH, 24%),
11.77 (s, 1H, NH, 75%), 10.01 (s, 1H, OH), 8.40 (dd, J = 8.0, 1.7 Hz, 2H), 8.20 (s, 1H,
CH=N, 26%), 8.07 (s, 1H, CH=N, 74%), 7.81 (ddd, J = 8.7, 6.9, 1.7 Hz, 2H), 7.74 – 7.52 (m,
4H), 7.44 – 7.34 (m, 2H), 6.86 (dd, J = 8.4, 5.8 Hz, 2H), 5.74 (s, 2H, CH2, 75%), 5.31 (s, 2H,

13
CH2, 25%). C NMR (75 MHz, DMSO-d6, 25°C, TMS): 176.75, 168.01, 163.38, 159.38,
144.74, 142.51, 142.43, 134.14, 128.86, 126.51, 124.99, 124.92, 121.53, 121.40, 115.89,
115.67, 47.97, 47.14. MS (ESI) for C22H17N3O3 [M + 1]+, calcd: 372,13, found: 372.13
N-(4-chlorobenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5d)
White solid; yield: 79 %, mp > 300 °C. IR (KBr): 3207, 3079, 2970, 1680, 1633, 1604, 1599,
1493 cm-1. 1H NMR (300 MHz, DMSO-d6, 25°C, TMS): 12.10 (s,1H, NH, 26%)12.03 (s,1H,
NH, 74%), 8.40 (dd, J = 8.1, 1.7 Hz, 2H), 8.31 (s, 1H, N=CH, 26%), 8.15 (s, 1H, N=CH,
74%), 7.90 – 7.83 (m, 2H), 7.79 – 7.76 (m, 2H), 7.71 – 7.64 (m, 2H), 7.56 – 7.52 (m, 2H),
13
7.40-7.33 (m, 2H), 5.79 (s, 2H, CH2, 74%), 5.17 (s, 2H, CH2, 26%). C NMR (75 MHz,
DMSO-d6, 25°C, TMS):176.74, 168.51, 166.51, 146.24, 143.08, 142.48, 134.51, 134.13,
133.95, 132.95, 128.86, 128.77, 126.49, 121.66, 121.56, 121.40, 115.91, 47.49, 47.22. MS
(ESI) for C22H16ClN3O2 [M + 1]+, calcd: 390,09, found: 390.09
N-(4-methoxybenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5e)
Yellow solid; yield: 90 %, mp > 300 °C. IR (KBr): 3210, 3281, 2952, 1680, 1637, 1603, 1493
1
cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 11.82 (s, 1H, NH, 26%), 11.78 (s, 1H,
NH, 74%), 8.36 (dd, J = 8.0, 1.7 Hz, 2H), 8.22 (s, 1H, N=CH, 25%), 8.07 (s, 1H, N=CH,
75%), 7.82 – 7.59 (m, 6H), 7.33 (m, 2H), 7.01 (dd, J = 8.7, 2H), 5.71 (s, 2H, CH2, 75%), 5.28
(s, 2H, CH2, 25%), 3.79( s, 3H, OCH3). 13C NMR (75 MHz, DMSO-d6, 25°C, TMS): 177.20,
168.62, 164.00, 161.30, 147.91, 144.79, 142.93, 134.59, 129.19, 127.00, 122.11, 122.05,
121.86, 116.38, 114.77, 55.79, 48.51, 47.65. MS (ESI) for C23H19N3O3 [M + 1]+, calcd:
386,14, found: 386.14
N-(4-(dimethylamino)benzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5f)
White solid; yield: 74 %, mp > 300 °C. IR (KBr): 3196, 3097, 2980, 1681, 1639, 1605, 1490
1
cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 11.71 (s, 1H, NH, 27%), 11.68 (s, 1H,
NH, 73%), 8.38 (dd, J = 8.0, 1.7 Hz, 2H), 8.15 (s, 1H, N=CH, 27%), 8.03 (s, 1H, N=CH,
73%), 7.82 (tdd, J = 8.7, 6.9, 1.8 Hz, 2H), 7.75 – 7.53 (m, 4H), 7.44 – 7.30 (m, 2H), 6.76 (dd,
J = 9.1, 2.7 Hz, 2H), 5.72 (s, 2H, CH2, 74%), 5.30 (s, 2H, CH2, 26%), 2.98 (s, 6H, NCH3).
13C NMR (75 MHz, DMSO-d6, 25°C, TMS):176.73, 167.73, 151.47, 145.30, 142.53, 142.45,
134.12, 128.48, 128.39, 126.51, 121.61, 121.37, 121.25, 115.90, 111.72, 47.11. MS (ESI) for
C24H22N4O2 [M + 1]+, calcd: 399,17, found: 399.17
N-(4-nitrobenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5g)
Yellow solid; yield: 86 %, mp > 300 °C. IR (KBr): 3234, 3090, 2962, 1693, 1635, 1611,
1
1593, 1521, 1493 cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 12.31 (s, 1H, NH,
26%), 12.24 (s, 1H, NH, 74%), 8.43 (s, 1H, N=CH, 25%), 8.41 (dd, J = 8.0, 1.7 Hz, 2H),
8.33( m,2H), 8.27 (s, 1H, N=CH, 75%), 8.14-8.00 (m, 2H), 7.87-7.67 (m, 4H), 7.41-7.35 (m,
13
2H), 5.85 (s, 2H, CH2, 74%), 5.39 (s, 2H, CH2, 25%). C NMR (75 MHz, DMSO-d6, 25°C,

TMS): 178.41, 168.89, 163.73, 147.87, 145.16, 142.42, 140.30, 134.16, 131.00, 128.10,
126.55, 126.41, 124.95, 123.94, 121.58, 121.46, 120.98, 115.90, 48.32, 47.29. MS (ESI) for
C22H16N4O4 [M + 1]+, calcd: 401,12, found: 401,12
N-(4-hydroxy-3-methoxybenzylidene)-2-(9-oxoacridin-10(9H)-yl)acetohydrazide (5h)
Yellow solid; yield: 77 %, mp > 300 °C. IR (KBr): 3327, 3221, 3092, 2986, 2630, 1677,
1
1635, 1604, 1495 cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 11.82 (s, 1H, NH,
27%), 11.78 (s, 1H, NH, 73%), 9.58 (s, 1H, OH), 8.41 (dd, J = 8.0, 1.7 Hz, 2H), 8.20 (s, 1H,
N=CH, 25%), 8.06 (s, 1H, N=CH, 75%), 7.85–7.79 (m, 2H), 7.68–7.63 (m, 2H), 7.46-7.11
(m, 4H), 7.89 (m, 1H), 5.77 (s, 2H, CH2, 73%), 5.32 (s, 2H, CH2, 27%), 3.83( s, 3H, OCH3).
13C NMR (75 MHz, DMSO-d6, 25°C, TMS):176.73, 168.06, 163.40, 148.95, 148.01, 145.61,
144.82, 142.54, 142.46, 134.11, 126.51, 125.45, 121.72, 121.56, 121.38, 115.93, 115.49,
115.49, 109.68, 55.67, 47.28. MS (ESI) for C23H19N3O4 [M + 1]+, calcd: 402,13, found:
402.12
2-(9-oxoacridin-10(9H)-yl)-N'-(propan-2-ylidene)acetohydrazide (5k)
Yellow solid; yield: 68 %, mp > 300 °C. IR (KBr): 3208, 3036, 2934, 1668, 1632, 1598, 1493
1
cm-1. H NMR (300 MHz, DMSO-d6, 25°C, TMS): 10.77 (s, 1H, NH, 27%), 10.66 (s, 1H,
NH, 73%), 8.38 (dd, J = 8.0, 1.7 Hz, 2H), 7.89 – 7.75 (m, 2H), 7.67 (d, J = 8.8 Hz, 1H), 7.57
(d, J = 8.7 Hz, 1H), 7.36 (t, J = 7.4 Hz, 2H), 5.59 (s, 2H, CH2, 73%), 5.36 (s, 2H, CH2, 27%),
2.06 ( s, 3H, CH3), 1.99 ( s, 3H, CH3). 13C NMR (75 MHz, DMSO-d6, 25°C, TMS): 176.71,
168.31, 163.38, 152.33, 142.42, 134.09, 126.50, 121.54, 121.34, 115.89, 115.75, 47.56, 47.29,
25.29, 17.29.
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Mohammed Aarjane: Conceptualization, Methodology, Writing- Original draft preparation
Siham Slassi: Data curation, software, Visualization, Investigation
Amina Amine: Supervision
Graphical