Efficient MW-Assisted Synthesis of Some New Isoquinolinone Derivatives With In Vitro Antitumor Activity

Article abstract of DOI:10.1002/jhet.2916

An efficient and convenient synthesis of novel [1,3]oxazino[3,2-b]isoquinoline-5,12-dione derivative 4 was achieved by the reaction of anthranilic acid with homophthalic anhydride under microwave irradiation, followed by cyclization with acetic anhydride. Some new isoquinolinone and fused isoquinolinone derivatives were prepared via reaction of compound 4 with different nitrogen nucleophiles by using reflux and a focused microwave reactor. Microwave irradiation favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of isoquinolinone derivatives. The structures of the prepared compounds were elucidated by IR, ¹H-NMR, and mass spectroscopy. Some of the newly prepared compounds were tested in vitro against a panel of three human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2, colon cancer HCT-116, and mammary gland breast MCF-7. Almost all of the tested compounds showed satisfactory activity.

Full text of DOI:10.1002/jhet.2916

Month 2017 Efficient MW-Assisted Synthesis of Some New Isoquinolinone Derivatives
With In Vitro Antitumor Activity
*
Mohamed H. Hekal and Fatma S. M. Abu El-Azm
Chemistry Department, Faculty of Science, Ain Shams University, Abbassia, 11566 Cairo, Egypt
*
E-mail: ftmsaber@yahoo.com
Received January 23, 2017
DOI 10.1002/jhet.2916
Published online 00 Month 2017 in Wiley Online Library (wileyonlinelibrary.com).
An efficient and convenient synthesis of novel [1,3]oxazino[3,2-b]isoquinoline-5,12-dione derivative 4
was achieved by the reaction of anthranilic acid with homophthalic anhydride under microwave irradiation,
followed by cyclization with acetic anhydride. Some new isoquinolinone and fused isoquinolinone
derivatives were prepared via reaction of compound 4 with different nitrogen nucleophiles by using reflux
and a focused microwave reactor. Microwave irradiation favored the formation of the desired products with
improved yields and shortened reaction times. This is a simple and green method for the synthesis of
1
isoquinolinone derivatives. The structures of the prepared compounds were elucidated by IR, H-NMR,
and mass spectroscopy. Some of the newly prepared compounds were tested in vitro against a panel of three
human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2, colon cancer HCT-116, and
mammary gland breast MCF-7. Almost all of the tested compounds showed satisfactory activity.
J. Heterocyclic Chem., 00, 00 (2017).
INTRODUCTION
applications, such as antidepressant [8,9], antitumor
[10], and antimicrobial activities [11–13]. Because of
their biological and pharmacological importance, several
methods have been reported for the synthesis of
isoquinolinones. Most of these methods involve the use
of either a preformed isoquinoline or homophthalic
acid, which is in turn obtained by a multistep sequence
[14–19]. Homophthalic acids are transformed into
isoquinolinones via isocoumarins [20,21], isoquinolone-
4-carboxylic acid [14–19], or homophthalimide [19]. In
continuation of our previous work on isoquinolines
[22–24], the present study was designed to synthesize
some new derivatives of isoquinoline and fused
isoquinoline.
Microwave (MW)-assisted synthesis is a branch of green
chemistry that has gained much attention in recent years.
Moreover, it is considered pollution-free and eco-friendly
and typically offers high yields, together with simplified
processing and handling [1] as compared with
conventional synthesis methods. In this method, reactions
occur more rapidly, safely, and with higher chemical
yields, often far better than conventional methods, which
require longer reaction times and larger quantities of
solvents and reagents, cause environmental pollution, and
contribute to health hazards [2]. Many heterocyclic
compounds have been synthetized by using MW
irradiation [3]. Six-membered heterocycles and their
fused derivatives have been reported among the
compounds synthetized via MW irradiation, using
cyclocondensation, cycloaddition, and multicomponent
reactions, generating good yield and short reaction time
in an easy and rapid way [4].
RESULTS AND DISCUSSION
Several isoquinoline and fused isoquinoline derivatives
were synthesized as anticancer [12,25], anti-inflammatory
[26], antimalarial [27] and anti-HIV [28]. In this research,
Isoquinolinones and 1,2-dihydroisoquinolines have
received a big amount of interest in medicinal chemistry
research [5]. Their structures are incorporated in several
alkaloids [6] and other pharmacologically important
compounds [7]. Many compounds containing the
isoquinolinone templates have widespread biological
condensation of homophthalic anhydride
1
with
anthranilic acid 2 under MW irradiation or fusion on an
oil bath at 170°C for 2 h afforded 2-(1,3-dioxo-3,4-
dihydroisoquinolin-2(1H)-yl)benzoic acid 3 (Scheme 1).
The chemical structure 3 was confirmed by analytical and
© 2017 Wiley Periodicals, Inc.

M. H. Hekal and F. S. M. Abu El-Azm
Vol 000
Scheme 1. Synthetic route for the preparation of compounds 3 and 4.
1
1
spectroscopic data (IR, H-NMR, and MS). Thus, the IR
spectrum of 3 showed νOH (br) at 3393–2547 cmꢀ1
νC═O (br) at
at 1722 cmꢀ1 and νC═O
at 1677 cmꢀ1. Furthermore, H-NMR spectrum (CDCl3)
revealed the absence of δ- 1H of CH2 protons at
4.39 ppm and the presence of δ-1H of C7-H at 6.34 ppm,
which was completely in accord with the assigned
structure.
,
(acid)
(cyclic amide)
1678 cmꢀ1. Moreover, 1H-NMR spectrum of 3 in
dimethyl sulfoxide (DMSO)-d6 showed the following
signals from low to high field at δ (ppm): 12.91 (s,
1H, COOH, exchangeable with D2O), 8.08–7.36 (m,
8H arom.) and 4.39–4.15 (dd, 2H, CH2, J = 22.5 Hz).
Also, the mass spectrum of compound 3 shows the
respective molecular ion peak at m/z = 281 (11.1%),
which upon loss of water molecule afforded the base
peak at m/z = 263.
The titled compound 5H,12H-benzo[4,5][1,3]oxazino[3,2-
b]isoquinoline-5,12-dione 4 was obtained in fairly good
yield upon cyclization of compound 3 by using freshly
distilled acetic anhydride (Scheme 1). The synthesis of
compound 4 was not possible by MW-assisted synthesis
because it involves the use of acetic anhydride, which is
not amenable to use under MW irradiation. The assigned
structure of 4 was consistent with the study of its IR
spectrum which devoid the broad band of OH and
displayed νC═O (δ-lactone) at 1767 cmꢀ1, νC═O (cyclic amide)
Compound 4 was formed via attack of the nitrogen
nucleophile of the amino group of anthranilic acid at the
carbonyl group of homophthalic anhydride (tetrahedral
mechanism) followed by 1,6-exo-trig cyclization with
elimination of 2 mol of water. The synthetic mechanism
for the target compound 4 is shown in Scheme 2.
[1,3]Oxazino[3,2-b]isoquinolinone derivative 4 was
used as key intermediate to synthesize varieties of
isoquinoline and fused isoquinoline derivatives via its
interaction with different nitrogen nucleophiles with the
aim to obtain more precise and interesting pharmaceutical
compounds. We have developed a new synthetic method
for synthesis of 2-substituted isoquinolinone derivatives
by using MW irradiation, which led to improved yields
and less reaction time.
All new isoquinolinone and fused isoquinolinone
derivatives were synthesized by both conventional
Scheme 2. Proposed mechanism for formation of compound 4.
Journal of Heterocyclic Chemistry
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New Isoquinolinone Derivatives With In Vitro Antitumor Activity
Scheme 5. Synthetic route for the preparation of compounds 8 and 9.
synthesis and MW-assisted synthesis by synthetic
Schemes 3–5.
The [1,3]oxazino[3,2-b]isoquinolinone derivative
4
stirred with hydrazine hydrate (80%) in dioxane at room
temperature afforded the dihydrazide derivative 5,
whereas refluxing dioxane yielded 6-amino-5H-
isoquinolino[2,3-a]quinazoline-5,12(6H)-dione 6 as the
sole product with 60% yield. Compound 6 was also
synthesized by using MW irradiation in fairly good yield
(82%) (Scheme 3).
Some new isoquinolinone derivatives 7a–g were
obtained from the reaction of [1,3]oxazino[3,2-b]
isoquinolinone derivative
4
with some nitrogen
nucleophiles such as cyanoacetohydrazide, ethyl
carbazate, p-toluenesulfonohydrazide, cyclohexylamine,
aniline, 2-aminothiophenol, and sulfanilamide (Scheme 4).
These nucleophilic substitution reactions were performed
under reflux and MW irradiation to determine which
method gives the best results. Reaction conditions,
substituents, yields, and reaction times are listed in Table 1.
A comparative analysis of percentage yields and total
reaction time for all synthesized isoquinolinone
derivatives by both conventional method and
MW-assisted method was carried out to find out if the
MW-assisted synthesis of isoquinolinone derivatives adds
any advantage or not. It was found that there is
improvement in percentage yields and reduction in the
reaction time of the synthesized isoquinolinone
derivatives. By using MW irradiation, reaction is possible
within few minutes, and it also improves the yield. This
would be highly advantageous for drug discovery
laboratories where small amounts of different analogues
have to be synthesized in short periods of time. MW-
assisted synthesis is quicker, high yielding, environment-
friendly, and shows cleaner chemistry [1,2]
After spectral analysis of all synthesized isoquinolinone
derivatives, it was observed that for all synthesized
isoquinolinone derivatives, the IR spectra value of N─H
stretching ranges between 3141 and 3371 cmꢀ1 and the
value of C═O stretches for amides of 2-substituted
Scheme 3. Synthetic route for the preparation of compounds 5 and 6.
isoquinolinone ranges between 1660 and 1721 cmꢀ1
.
After analyzing the 1H-NMR data, the presence of dd
δ-1H value of CH2 protons of isoquinolinone ring (Ha,
Hb) between 3.59 and 4.42 ppm for all 2-substituted
isoquinolinone derivatives was observed (Fig. 1).
Furthermore, new fused isoquinolinone derivatives were
obtained when compound
4
was reacted with
semicarbazide hydrochloride in the presence of
anhydrous sodium acetate under reflux in glacial acetic
acid or MW irradiation to yield the annelated
triazoloquinazoline derivative 8. The structure of
Scheme 4. Synthetic route for the preparation of compounds 7a–g. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

M. H. Hekal and F. S. M. Abu El-Azm
Vol 000
Table 1
Comparative study of conventional versus MW method.
Reflux
Microwave (MW)
Time
reaction
(h)
Yield
(%)
700 W
Time reaction
(min)
Compound
R
Yield (%)
mp °C
7a
7b
7c
7d
7e
7f
NHCOCH2CN
NHCOOEt
4-CH3C6H4SO2NH
C6H11
C6H5
2-SHC6H4NH
4-NH2SO2C6H4NH
8
7
10
6
7
8
62
69
45
53
61
42
66
3
4
6
3
5
3
4
85
89
90
92
96
82
93
264–266
188–190
234–236
90–92
251–253
124–126
322–324
7g
9
Table 2
Cytotoxicity (IC50) of the tested compounds on different cell lines.
IC50 (μg/mL)a
Compd.
no.
HePG2
HCT-116
MCF-7
3
4
5
6
7a
7b
7c
7d
7e
7f
7g
8
49.4 2.9
25.9 1.8
9.0 0.8
86.2 4.3
17.9 1.4
58.1 3.2
13.3 1.2
64.0 3.6
7.6 0.7
80.3 3.9
32.5 2.1
69.7 3.8
43.0 2.7
7.9 0.5
69.4 3.3
15.4 1.4
11.3 1.1
80.1 4.1
39.4 2.3
33.0 2.0
9.3 0.9
74.5 3.9
36.5 2.8
25.8 2.5
90.2 4.9
41.3 2.9
17.0 1.8
20.4 2.0
65.4 3.7
8.3 0.8
81.3 4.2
54.4 3.2
92.1 4.5
10.6 1.3
5.4 0.3
Figure 1. General structure for isoquinolinone derivatives. [Color figure
can be viewed at wileyonlinelibrary.com]
compound 8 was confirmed by spectroscopic data. The IR
spectrum showed that bands at 3310, 1686, and
1625 cmꢀ1 attributed to NH, C═O, and C═N groups,
respectively. The 1H-NMR spectrum of compound 8
showed the following signals from low to high field at δ
(ppm): 10.9 (s, 1H, NH, exchangeable with D2O),
9.04–7.43 (m, 8H arom.), 6.61 (s, 1H, C4─H). The
recorded peak in the mass spectrum of compound 8 at
m/z = 302 (5.22%) indicates the removal of two molecules
of water under the reaction conditions via ring opening
followed by double cyclization in situ (Scheme 5).
However, fusion of compound 4 with ammonium
acetate on an oil bath at 170°C or under MW irradiation
afforded 5H-isoquinolino[2,3-a]quinazoline-5,12(6H)-dione
9 (Scheme 5).
47.8 2.6
7.2 0.5
74.3 3.6
51.6 2.9
89.7 4.6
23.2 1.7
5.3 0.2
9
5-FU
5-FU, 5-fluorouracil.
aIC50 (μg/mL): 1–10 (very strong), 11–20 (strong), 21–50 (moderate), 51–
100 (weak), and above 100 (noncytotoxic).
strong activity) with IC50 9.0 0.8 and 7.6 0.7 μg/mL for
HePG-2 cell line, respectively. Compounds 7e and 7c
exhibited very strong activity with IC50 7.2
0.5 and
9.3 0.9 μg/mL for HCT-116 cell line, respectively.
Compound 7e showed very strong activity with IC50
8.3 0.8 μg/mL for MCF-7 cell line. Compounds 7a and
7c showed strong activity toward HePG-2 cell IC50
17.9 1.4 and 13.3 1.2 μg/mL, while compounds 4
and 5 showed strong activity toward HCT-116 cell IC50
Pharmacological activity. Antitumor activity using in vitro
Ehrlich ascites assay. We assessed the cytotoxic activity
of the compounds (listed in Table 2 and shown in Fig. 2)
against three human tumor cell lines, namely,
hepatocellular carcinoma (liver) HePG2, colon cancer
HCT-116, and mammary gland breast MCF-7.
In general, the cytotoxic activity of the tested
compounds ranged from very strong to weak activity.
Compound 7e showed approximately equal activity to the
5-FU as a standard for HePG-2 cell line with IC50
7.6 0.7 and 7.9 0.5 μg/mL, respectively. The optimal
results were observed for compounds 5 and 7e (very
15.4
strong activity toward MCF-7 cell line was observed with
compounds 7b, 7c, and 9 with IC50 17.0 1.8,
1.4 and 11.3
1.1 μg/mL, respectively. Also,
20.4 2.0, and 10.6 1.3 μg/mL, respectively. Moderate
activity toward HePG-2, HCT-116, and MCF-7 cell lines
was observed with compounds 3, 4, 5, 7a, 7b, 7d, 7g,
and 9.
Journal of Heterocyclic Chemistry
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Month 2017
New Isoquinolinone Derivatives With In Vitro Antitumor Activity
Figure 2. Cytotoxic activity of the tested compounds on different cell lines. [Color figure can be viewed at wileyonlinelibrary.com]
Structure–activity relationship.
DNA is made up of
with either one of the nucleobases of the DNA and
causes it damage.
• Compound 5 showed very strong activity; this is due to
the presence of 3 NH and 2 NH2 groups available to
form hydrogen bond with either one of the nucleobases
of the DNA and causes it damage.
• Compound 7c showed very strong activity; this is
due the presence of 2 NH which can form hydrogen
bond with either one of the nucleobases of the DNA
and causes it damage. Also, the presence of the
SO2Ph group as a strong electron attracting group
rendered the molecule positively charged forming
electrostatic attraction with the DNA nucleobases.
Moreover, the SO2 group acts on the mitotic spindle
[31].
chemical building blocks called nucleotides. The four
types of nitrogen bases found in nucleotides are as
follows: adenine (A), thymine (T), guanine (G), and
cytosine (C). The base adenine always pairs with
thymine, while guanine always pairs with cytosine
through hydrogen bond. The cytotoxic activity of the
tested compounds toward different cell lines depends on
two factors [29,30]: (i) the formation of intermolecular
hydrogen bond with DNA bases and (ii) the positive
charge on the tested compounds attracted to the negative
charge on the cell wall. By comparing the experimental
cytotoxicity of the compounds reported in this study to
their structures, the following structure-activity relationship
was postulated.
• Compounds 7a, 7b, and 9 contain NH group forming
hydrogen bond with either one of the nucleobases of
the DNA and causes it damage.
• Compound 7e showed very strong activity; this is due to
the presence of the NH group which may be added to any
unsaturated moiety in DNA or forming hydrogen bond
Scheme 6. Mechanism of the antitumor action of CNDAC. [Color figure can be viewed at wileyonlinelibrary.com]
Journal of Heterocyclic Chemistry
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M. H. Hekal and F. S. M. Abu El-Azm
Vol 000
Scheme 7. Mechanism of the antitumor action of compound 7e. [Color figure can be viewed at wileyonlinelibrary.com]
20-C-Cyano-20-deoxy-1-β-D-arabinopentofuranosylcytosine
(CNDAC) [32] is a nucleoside analogue with a novel
mechanism of action that is being evaluated in clinical
trials. Incorporation of CNDAC triphosphate into DNA
and extension during replication lead to single-strand
breaks directly caused by β-elimination. These breaks, or
the lesions that arise from further processing, cause cells
to arrest in G2. The electron withdrawing effect [33] of the
cyano group at the arabinose 20-β-position increases the
acidity of the 20-α proton and facilitates a β-elimination
reaction involving an oxygen of the phosphate group at
the 30-β position that leads to single strand break that
affords a DNA molecule lacking a 30-hydroxyl, which
prevents its repair by ligation and leads to inhibition of the
cell cycle at the G2 phase (Scheme 6).
green method for the synthesis of isoquinolinone
derivatives. The tested compounds showed very strong to
weak cytotoxic activity against three anticancer cell lines.
The best results were observed for compounds 5, 7e, and
7c (very strong activity). Compound 7e showed
approximately equal activity to the 5-FU as a standard
against HePG2 cell line.
EXPERIMENTAL
All melting points were taken on a Griffin and George
melting-point apparatus (Griffin & George Ltd., Wembley,
Middlesex, UK) and are uncorrected. IR spectra were
recorded on Pye Unicam SP1200 spectrophotometer (Pye
Unicam Ltd., Cambridge, UK) by using the KBr wafer
Also, the presence of NH and OH groups enhances the
cytotoxicity of compound 7e. The proposed mechanism
of DNA interaction with compound 7e as compared with
CNDAC is shown in Scheme 7.
1
technique. H-NMR spectra were determined on a Varian
Gemini 300 MHz (Santa Clara, CA) by using
tetramethylsilane as internal standard (chemical shifts in δ
scale). EI-MS was measured on a Shimadzu GC-MS
(Columbia, MD) operating at 70 eV. Elemental analyses
were carried out at the Microanalytical Unit, Faculty of
Science, Ain Shams University, using a Perkin-Elmer
2400 CHN elemental analyzer (Waltham, MA), and
satisfactory analytical data ( 0.4) were obtained for all
compounds. MW experiments were carried out by using a
CEM Discover Labmate microwave apparatus (300 W
with CHEMDRIVER software; Matthews, NC, USA). The
homogeneity of the synthesized compounds was
CONCLUSION
The objectives of the present study were to synthesize
some new isoquinolinone and fused isoquinolinone
derivatives by using reflux and a focused MW reactor
and study their cytotoxic activity. MW irradiation favored
the formation of the desired products with improved
yields and shortened reaction times. This is a simple and
Journal of Heterocyclic Chemistry
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Month 2017
New Isoquinolinone Derivatives With In Vitro Antitumor Activity
controlled by thin layer chromatography (TLC), using
aluminum sheet silica gel F254 (Merck).
dried, and then recrystallized from dioxane to give 6 as
yellow crystals, yield 60%. mp 230–232°C. IR (υ/cmꢀ1):
3302, 3201 (NH2), 1669 (C═O). H-NMR (DMSO-d6) δ
1
Synthesis of 2-(1,3-dioxo-3,4-dihydroisoquinolin-2(1H)-yl)
benzoic acid 3.
A mixture of homophthalic anhydride
(ppm): 9.09–7.36 (m, 8H arom.), 7.01 (s, 1H, C7─H),
5.71 (s, 2H, NH2, exchangeable with D2O). MS m/z (%):
277 (M+; 100), 248 (54.7), 220 (10.8), 205 (4.6), 190
(4.6), 115 (8.9), 89 (14.76), 77 (7.3). Anal. Calcd. for
C16H11N3O2 (277.28): C, 69.31; H, 4.00; N, 15.15.
Found: C, 69.21; H, 3.92; N, 14.99.
(1.62 g, 10 mmol) and anthranilic acid (1.37 g, 10 mmol)
was exposed to MW at 900 W for 5 min and undergoes
fusion on an oil bath at 170°C for 2 h. After cooling, the
reaction mixture was treated with ethanol and the solid
formed was filtered, dried, and recrystallized from EtOH
to give 3 as pale yellow crystals (yield 72% with MW
and 53% with fusion), mp 224–226°C. IR (ν/cmꢀ1): br
3393–2547 (OHacid), 1722 (C═Oacid), 1678 (C═Ocyclic
Method 2.
A mixture of compound 4 (2.63 g,
10 mmol) and hydrazine hydrate (0.5 mL, 10 mmol) was
exposed to MW at 700 W for 3 min. After cooling, the
reaction mixture was treated with ethanol and the solid
formed was filtered, dried, and recrystallized from
dioxane to give 6 as yellow crystals, yield 82% (identity
mp mixed mp, TLC, and IR).
1
amide). H-NMR (DMSO-d6) δ (ppm): 12.91 (s, 1H, OH,
exchangeable with D2O), 8.08–7.36 (m, 8H arom.),
4.39–4.15 (dd, 2H, CH2, J = 22.5 Hz). ms m/z (%): 281
(M+; 11.1), 263 (100), 236 (78.97), 207 (52.42), 118
(61.49), 90 (92.39), 77 (9.65). Anal. Calcd. for
C16H11NO4 (281.26): C, 68.32; H, 3.94; N, 4.98. Found:
C, 68.29; H, 3.82; N, 4.93.
General procedure for synthesis of isoquinolinone
derivatives (7a–g). Method A (reflux).
A mixture of
compound 4 (10 mmol) and hydrazine derivatives
(10 mmol) or 1°ry amines (10 mmol) in dioxane (20 mL)
was heated under reflux for 6–10 h. The precipitated
solid product was filtered, washed with ethanol, dried,
and finally recrystallized from the appropriate solvent.
Method B (MW). A mixture of compound 4 (10 mmol)
and hydrazine derivatives (10 mmol) or 1°ry amines
(10 mmol) was subjected to MW irradiation (Table 1 ).
After cooling, the reaction mixture was treated with
ethanol and the solid formed was filtered, dried, and
Synthesis
isoquinoline-5,12-dione 4.
of
5H,12H-benzo[4,5][1,3]oxazino[3,2-b]
A mixture of compound 3
(2.81 g, 10 mmol) and acetic anhydride (10 mL) was
heated on water bath for 15 min. The deposited solid on
hot was collected by filtration, washed with petroleum
ether (bp 80–100°C), dried, and recrystallized from
dioxane to give 4 as yellow crystals, yield 82%, mp
226–228°C. IR (ν): 1767 (C═Oδ-lactone), 1677 cmꢀ1
1
(C═Ocyclic amide). H-NMR (CDCl3) δ (ppm): 9.36–7.42
(m, 8H arom.), 6.34 (s, 1H, C7-H). ms m/z (%): 263 (M+;
67.1), 235 (58.6), 207 (100), 179 (47.4), 89 (54.2), 77
(9.5). Anal. Calcd. for C16H9NO3 (263.25): C, 73.00; H,
3.45; N, 5.32. Found: C, 73.07; H, 3.37; N, 5.35.
recrystallized from the appropriate solvent.
N0-(2-Cyanoacetyl)-2-(1,3-dioxo-3,4-dihydroisoquinolin-2(1H)-
yl)benzohydrazide 7a.
Recrystallized from dioxane as
white crystals, mp 264–266°C. IR (υ/cmꢀ1): 3274 (NH),
1
2250 (C☰N), 1721, 1667 (C═O). H-NMR (DMSO-d6) δ
Synthesis
hydrazinyl-2-oxoethyl)benzamide 5.
of
N-(2-(hydrazinecarbonyl)phenyl)-2-(2-
(ppm): 10.40 (s, 1H, NH, exchangeable with D2O), 10.21
(s, 1H, NH, exchangeable with D2O), 8.04–7.37 (m, 8H
arom.), 4.33–4.12 (dd, 2H, CH2, J = 22.5 Hz), 3.67 (s,
2H, CH2). MS m/z (%): 362 (M+; 1.43), 337 (100), 322
(48.7), 207 (5.8), 115 (66.9), 89 (83). Anal. Calcd. for
C19H14N4O4 (362.34): C, 62.98; H, 3.89; N, 15.46.
Found: C, 63.00; H, 3.91; N, 15.50.
Hydrazine hydrate
(0.5 mL, 10 mmol) was added dropwise to a solution of
compound 4 (2.63 g, 10 mmol) in dioxane (30 mL) with
stirring at room temperature for 0.5 h. The separated
solid was filtered off, dried, and recrystallized from
ethanol to give 5 as white crystals, yield 43%. mp
196–198°C. IR (υ/cmꢀ1): 3325, 3250, 3203 (NH, NH2),
Ethyl
2-(2-(1,3-dioxo-3,4-dihydroisoquinolin-2(1H)-yl)
1
1675, 1659 (C═O). H-NMR (DMSO-d6) δ (ppm): 11.81
benzoyl)hydrazinecarboxylate 7b.
Recrystallized from
benzene as buff crystals, mp 188–190°C. IR (υ/cmꢀ1):
(s, 1H, NH, exchangeable with D2O), 10.11 (s, 1H, NH,
exchangeable with D2O), 9.13 (s, 1H, NH, exchangeable
with D2O), 8.50–7.14 (m, 8H arom.), 4.42 (br s, 4H,
2NH2, exchangeable with D2O), 3.71 (s, 2H, CH2). MS
m/z (%): 327 (M+; 52.53), 277 (10.97), 264 (5.82), 236
(10.17), 120 (100), 115 (14.3), 89 (86.73), 77 (30.12).
Anal. Calcd. for C16H17N5O3 (327.34): C, 58.71; H,
5.23; N, 21.39. Found: C, 58.82; H, 5.15; N, 21.28.
1
3256, 3185 (NH), 1729, 1677 (C═O). H-NMR (CDCl3)
δ (ppm): 8.21–7.24 (m, 8H arom.), 7.90 (s, 1H, NH,
exchangeable with D2O), 6.66 (s, 1H, NH, exchangeable
with D2O), 4.42–4.15 (dd, 2H, CH2, J = 24 Hz), 4.05 (q,
2H, CH2), 1.16 (t, 3H, CH3). MS m/z (%): 349 (M+;
ꢀ18, 1.23), 330 (1.07), 264 (7.06), 236 (26.58), 180
(28.91), 152 (16.33), 90 (100). Anal. Calcd. for
Synthesis of 6-amino-5H-isoquinolino[2,3-a]quinazoline-
5,12(6H)-dione 6. Method 1. A mixture of compound 4
(2.63 g, 10 mmol) and hydrazine hydrate (0.5 mL,
10 mmol) in dioxane (30 mL) was heated under reflux
for 2 h. The solid formed after cooling was filtered off,
C19H17N3O5 (367.36): C, 62.12; H, 4.66; N, 11.44.
Found: C, 62.02; H, 4.53; N, 11.40.
N0-(2-(1,3-Dioxo-3,4-dihydroisoquinolin-2(1H)-yl)benzoyl)-4-
methylbenzene sulfonohydrazide 7c.
Recrystallized from
ethanol as yellow crystals, mp 234–236°C. IR (υ/cmꢀ1):
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

M. H. Hekal and F. S. M. Abu El-Azm
Vol 000
3325, 3141 (NH), 1718, 1684, 1660 (C═O). 1H-NMR
(DMSO-d6) δ (ppm): 10.49 (s, 1H, NH, exchangeable
with D2O), 9.79 (s, 1H, NH, exchangeable with D2O),
8.02–7.16 (m, 12H arom.), 4.25–3.95 (dd, 2H, CH2,
J = 22.2 Hz), 2.28 (s, 3H, CH3). MS m/z (%): 449
(M+; 4.54), 431 (46.47), 384 (7.17), 247 (64.05), 219
(37.05), 191 (31.98), 165 (87.90), 115 (44.93), 40 (100).
Anal. Calcd. for C23H19N3O5S (449.48): C, 61.46; H,
4.26; N, 9.35; S, 7.13. Found: C, 61.31; H, 4.33; N, 9.22;
acetate (1 g) in glacial acetic acid (20 mL) was refluxed
for 10 h. The deposited solid on hot was filtered off,
washed with ethanol, dried, and recrystallized from
dioxane to give 8 as pale yellow crystals, yield 56%, mp
290–292°C. IR (υ/cmꢀ1): 3310 (NH), 1686 (C═O), 1625
1
(C═N). H-NMR (DMSO-d6) δ (ppm): 10.9 (s, 1H, NH,
exchangeable with D2O), 9.04–7.43 (m, 8H arom.), 6.61
(s, 1H, C4─H). MS m/z (%): 302 (M+; 5.22), 277 (46.7),
234 (19.8), 190 (85.1), 179 (52), 115 (83.3), 90 (63.7),
77 (48). Anal. Calcd. for C17H10N4O2 (302.29): C, 67.55;
H, 3.33; N, 18.53. Found: C, 67.45; H, 3.29; N, 18.50.
S, 6.96.
N-Cyclohexyl-2-(1,3-dioxo-3,4-dihydroisoquinolin-2(1H)-yl)
benzamide 7d.
Recrystallized from petroleum ether
Method 2.
A mixture of compound 4 (2.63 g,
80–100°C as white crystals, mp 90–92°C. IR (υ/cmꢀ1):
3326 (NH), 2930, 2853 (aliph. CH2), 1723, 1677 (C═O).
1H-NMR (CDCl3) δ (ppm): 8.23–7.23 (m, 8H arom.),
5.85 (s, 1H, NH, exchangeable with D2O), 4.35–4.12
(dd, 2H, CH2, J = 22 Hz), 3.66 (m, 1H, CHcyclohexane),
1.65–1.07 (m, 10H, CH2cyclohexane). MS m/z (%): 362
(M+; 8.60), 264 (100), 263 (37.25), 236 (89.37), 208
(18.75), 90 (46.17), 77 (11.88). Anal. Calcd. for
C22H22N2O3 (362.42): C, 72.91; H, 6.12; N, 7.73.
10 mmol), semicarbazide hydrochloride (1.11 g,
10 mmol), and anhydrous sodium acetate (1 g) was
exposed to MW at 800 W for 3 min. After cooling, the
reaction mixture was treated with boiling water and the
solid formed was filtered, dried, and recrystallized from
dioxane to give 8 as pale yellow crystals, yield 85%
(identity mp mixed mp, TLC, and IR).
Synthesis of 6H-isoquinolino[2,3-a]quinazoline-5,12-dione
9. Method 1.
A mixture of compound 4 (2.63 g,
Found: C, 73.00; H, 5.95; N, 7.66.
10 mmol) and ammonium acetate (10 g) was fused in an
oil bath at 170°C for 1 h. The deposited solid on hot was
filtered off, washed with water for several times, dried,
and recrystallized from DMF to give 9 as yellow crystals,
yield 78%, mp > 320°C. IR (υ/cmꢀ1): 3148 (NH), 1674
2-(1,3-Dioxo-3,4-dihydroisoquinolin-2(1H)-yl)-N-phenylbenzamide
7e. Recrystallized from dioxane as pale yellow crystals,
mp 251–253°C. IR (υ/cmꢀ1): 3276 (NH), 1721, 1674
1
(C═O). H-NMR (DMSO-d6) δ (ppm): 10.17 (s, 1H, NH,
exchangeable with D2O), 8.07–6.61 (m, 13H arom.),
4.34–4.02 (dd, 2H, CH2, J = 22.5 Hz). Anal. Calcd. for
C22H16N2O3 (356.37): C, 74.15; H, 4.53; N, 7.86. Found:
C, 74.03; H, 4.42; N, 7.79.
2-(1,3-Dioxo-3,4-dihydroisoquinolin-2(1H)-yl)-N-(2-mercaptophenyl)
1
(C═O). H-NMR (DMSO-d6) δ (ppm): 11.83 (s, 1H, NH,
exchangeable with D2O), 9.27–7.31 (m, 8H arom.), 6.21
(s, 1H, C7─H). Anal. Calcd. for C16H10N2O2 (262.26): C,
73.27; H, 3.84; N, 10.68. Found: C, 73.31; H, 3.81; N,
10.65.
benzamide 7f.
Recrystallized from ethanol as yellow
Method 2.
A mixture of compound 4 (2.63 g,
crystals, mp 124–126°C. IR (υ/cmꢀ1): 3358 (NH), 1721,
1682 (C═O). 1H-NMR (DMSO-d6) δ (ppm): 10.38 (s,
1H, NH, exchangeable with D2O), 8.08–6.42 (m, 12H
arom.), 5.53 (s, 1H, SH, exchangeable with D2O),
4.33–4.055 (dd, 2H, CH2, J = 22.5 Hz). Anal. Calcd. for
C22H16N2O3S (388.44): C, 68.02; H, 4.15; N, 7.21; S,
10 mmol) and ammonium acetate (10 g) was exposed to
MW at 900 W for 4 min. After cooling, the reaction
mixture was treated with boiling water and the solid
formed was filtered, dried, and recrystallized from DMF
to give 9 as pale yellow crystals, yield 93% (identity mp
mixed pm, TLC, and IR).
8.25. Found: C, 67.94; H, 4.01; N, 7.18; S, 8.23.
Pharmacological activity. Cytotoxicity assay.
The
2-(1,3-Dioxo-3,4-dihydroisoquinolin-2(1H)-yl)-N-(4-sulfamoylphenyl)
benzamide 7g. Recrystallized from dioxane as pale yellow
cytotoxic activity of 13 compounds was tested against
three human tumor cell lines, namely, hepatocellular
carcinoma (liver) HePG-2, colon cancer HCT-116, and
mammary gland (breast) MCF-7. The cell lines were
obtained from the ATCC via the Holding Company for
Biological Products and Vaccines (Cairo, Egypt).
5-Fluorouracil was used as a standard anticancer drug
for comparison. The reagents used were RPMI-1640
medium, MTT, DMSO, and 5-fluorouracil (Sigma Co.,
St. Louis, MO, USA) and fetal bovine serum (GIBCO,
Paisley, UK).
crystals, mp 322–324°C. IR (υ/cmꢀ1): 3371, 3303, 3259
1
(NH, NH2), 1719, 1670 (C═O). H-NMR (DMSO-d6) δ
(ppm): 10.70 (s, 1H, NH, exchangeable with D2O), 8.04–
7.40 (m, 12H arom.), 7.20 (s, 2H, NH2, exchangeable
with D2O), 4.34–4.16 (dd, 2H, CH2, J = 21 Hz). MS
m/z (%): 435 (M+; 1.73), 421 (1.52), 364 (8.99), 278
(19.40), 265 (89.64), 237 (100), 125 (96.12), 90 (86.95).
Anal. Calcd. for C22H17N3O5S (435.45): C, 60.68; H,
3.93; N, 9.65; S, 7.36. Found: C, 60.55; H, 4.09; N, 9.47;
S, 7.22.
The different cell lines [34,35] mentioned in the
preceding texts were used to determine the inhibitory
effects of compounds on cell growth by using the MTT
assay. This colorimetric assay is based on the conversion
Synthesis of 9H-isoquinolino[2,3-a][1,2,4]triazolo[1,5-c]
quinazoline-2,9(1H)-dione 8. Method 1.
A mixture of
(2.63 g, 10 mmol), semicarbazide
hydrochloride (1.11 g, 10 mmol), and anhydrous sodium
compound
4
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DOI 10.1002/jhet

Month 2017
New Isoquinolinone Derivatives With In Vitro Antitumor Activity
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formazan derivative by mitochondrial succinate
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DOI 10.1002/jhet