Synthesis, characterization, antioxidant and antitumor evaluation of new phthalocyanines containing peripherally functionalized fused heterocyclic compounds

Article abstract of DOI:10.1016/j.dyepig.2018.02.048

Our work has been heavily engaged in the synthesis of novel phthalocyanines with various functional groups and/or heterocycles at peripheral and axial positions via the reaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with 1,4-diazabicyclo[2.2.

Full text of DOI:10.1016/j.dyepig.2018.02.048

Accepted Manuscript
Synthesis, characterization, antioxidant and antitumor evaluation of new
phthalocyanines containing peripherally functionalized fused heterocyclic compounds
Ahmed A. Fadda, Rasha E. El-Mekawy, Nanees N. Soliman, Asmaa M. Allam,
Mohammed T. Abdelaal
PII:
S0143-7208(18)30042-1
10.1016/j.dyepig.2018.02.048
DYPI 6581
DOI:
Reference:
To appear in: Dyes and Pigments
Received Date: 5 January 2018
Revised Date: 13 February 2018
Accepted Date: 27 February 2018
Please cite this article as: Fadda AA, El-Mekawy RE, Soliman NN, Allam AM, Abdelaal MT,
Synthesis, characterization, antioxidant and antitumor evaluation of new phthalocyanines containing
peripherally functionalized fused heterocyclic compounds, Dyes and Pigments (2018), doi: 10.1016/
j.dyepig.2018.02.048.
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ACCEPTED MANUSCRIPT
Graphical Abstract
Synthesis, characterization, antioxidant and antitumor evaluation of
new phthalocyanines containing peripherally functionalized fused
heterocyclic compounds
Ahmed A. Faddaa*, Rasha E. El-Mekawyb,c, Nanees N. Solimana, Asmaa M.
Allamd, Mohammed T. Abdelaald
a Chemistry Department, Faculty of Science, Mansoura University, 35516 Mansoura, Egypt
bPermanent address: Department of Petrochemicals, Egyptian Petroleum Research Institute, Nasr
City, Cairo, Egypt
cCurrent address: Present Address: Department of Chemistry, Faculty of Applied Science, Umm Al-
Qura University, Makkah Al Mukarrama, Saudi Arabia
d Chemistry Department, Faculty of Science, Menoufia University, Menoufia, Egypt
SUMMARY
Novel phthalocyanines was synthesized. The synthesized compounds were screened for their
antioxidant and cytotoxicity activity. Compounds 13 and 14 are the most active compound
against antioxidant and cytotoxicity activity.

ACCEPTED MANUSCRIPT
Synthesis, characterization, antioxidant and antitumor evaluation of
new phthalocyanines containing peripherally functionalized fused
heterocyclic compounds
Ahmed A. Fadda a*, Rasha E. El-Mekawy b,c, Nanees N. Soliman a, Asmaa M. Allam
d, Mohammed T. Abdelaal d
aChemistry Department, Faculty of Science, Mansoura University, 35516 Mansoura,
Egypt
bPermanent address: Department of Petrochemicals, Egyptian Petroleum Research
Institute, Nasr City, Cairo, Egypt
cCurrent address: Present Address: Department of Chemistry, Faculty of Applied
Science, Umm Al-Qura University, Makkah Al Mukarrama, Saudi Arabia
dChemistry Department, Faculty of Science, Menoufia University, Menoufia, Egypt
ABSTRACT
Our work has been heavily engaged in the synthesis of novel phthalocyanines with
various functional groups and /or heterocycles at peripheral and axial positions via the
reaction
of
2,3-dichloro-5,6-dicyano-1,4-benzoquinone
(DDQ)
with
1,4-
diazabicyclo[2.2.2]octane (DBO). Also, reaction of modified phthalonitrile derivatives 4,
8, 9 and 13 with hydroquinone or DDQ afforded the corresponding new phthalocyanine
derivatives 5, 10, 11 and 14, respectively. Moreover, a new generation of phthalocyanine
derivatives 17, 21a,b and 25 has been synthesized by cyclotetramerization of phthalic
anhydride derivatives 15, 20 a, b and 24 in the presence of 1,3-divinyl-1,1,3,3-
tetramethyldisilazane as catalyst. The structures of newly synthesized compounds have
been established by both elemental and spectral analyses. The antioxidant activity of the
products was screened in series of in vitro tests. In addition, the toxicity of the
synthesized compounds was studied at four different cell lines HepG2, WI-38, Vero and
MCF-7 cell lines. According to our results, compounds 13 and 14 have a very strong
activity against all cell lines and act as good antioxidant agents.
* Corresponding author. Tel.: 20502946636; Fax: 20502246781.
E-mail address: afadda50@yahoo.com (Ahmed A. Fadda)
Keywords: Phthalocyanines; Disilazanes; Cyclotetramerization; Phthalic anhydrides;
antioxidant; antitumor
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1.
INTRODUCTION
Phthalocyanines (Pcs) are of continuing interest as organic materials which possess
interesting high thermal stability, semiconductivity, photoconductivity, etc [1].
Phthalocyanines are important heterocyclic nitrogen conjugated compounds. Many Pcs
and their substituted derivatives were found to be of great importance and commercial
interest as dyes and pigments. It has been reported that many of the metal
phthalocyanines were used in medicinal chemistry. The first photosensitizers,
hematoporphyrin derivatives and photofrin have been used in photodynamic therapy
(PDT) [2-4]. Photodynamic therapy is used in the treatment of cancer followed by
activation of the chemical by light [5, 6].
Among the various reported works concerning metal phthalocyanines in photodynamic
therapy, relatively a few studies were done on metal free phthalocyanines despite the
potential use of these compounds as nonlinear optical materials. Our studies have mainly
focused on the synthesis of metal free phthalocyanines to study their biological activity
as antioxidant and anticytotoxic agents. The common method to synthesize substituted
phthalocyanines is to prepare the phthalonitrile precursors with required substituent,
then synthesize the corresponding phthalocyanine by cyclotetramerization of the
substituted phthalonitriles [7-9]. However, the traditional way usually required more
than two reaction steps and time consuming performance. So, it’s necessary to search for
a new strategy to prepare new phthalocyanine compounds. Generally, phthalocyanines
synthesis is performed in a single step reaction, starting from phthalic anhydride,
phthalimide, or phthalonitrile [10- 15]. The main features that phthalocyanines must
meet to have high therapeutic efficacy could be listed as: (1) low toxicity in the dark; (2)
high photo toxicity when light activated; (3) high selectivity and specificity for target
tumor; (4) rapid elimination from the body; (5) absorption in optical transmission
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window of biological tissues; (6) high quantum yield of singlet oxygen production; (7)
solubility in water-based solution; (8) stability under physiological conditions.
On the other hand, pyridine, imidazolone, isooxazole, quinoline, phthalimide and
pyridoquinazoline are among the best known nitrogen heterocyclic compounds which
have a broad spectrum of biological activity. The above mentioned facts prompted us to
synthesize a new series of phthalocyanine derivatives to evaluate their antioxidant and
cytotoxicity against different cell lines. No details regarding the synthesis and the
biological behaviour of the newly synthesized phthalonitriles, phthalic anhydrides and
phthalocyanines as antioxidant and anticytotoxic agents have been reported so far.
2. Materials and methods
2.1. General remarks
All melting points are incorrect in degree centigrade and determined on Gallenkamp
electric melting point apparatus. The infrared (IR) spectra were recorded (KBr disk) on a
Mattson 5000 FTIR spectrometer at the Faculty of Science, Mansoura University, Egypt.
1
The H-NMR and 13C NMR spectra were determined on a Bruker WPSY 200 MHz
spectrometer with tetramethylsilane (TMS) as an internal standard and the chemical shifts
are in δ ppm using dimethylsulfoxide (DMSO-d6) as a solvent. The mass spectra were
recorded at 70 eV with Varian MAT 311 at the Microanalytical Center, Faculty of
Science, Cairo University. Elemental analyses (C, H and N) were carried out at the
Faculty of Science, Cairo University. The results were found to be in a good agreement
(± 0.03) with the calculated values.
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2.2.
Synthesis
of
2,3,9,10,16,17,23,24-octachloro-1,4,8,11,15,18,22,25-
octaoxophthalocyanine (2)
A mixture of 2,3-dichloro-4,5-dicyano-1,4-benzoquinone (DDQ) (0.45 gm, 2 mmol) and
1,4-diazabicyclo[2.2.2]octane (DBO) (0.29 gm, 2.6 mmol) was flushed with nitrogen gas
o
and heated at 200 C for 30 min, then 25 ml of ethylene glycol was added. The mixture
o
was continued heating with stirring under nitrogen gas at 150 C for 10 hrs. After
removing the solvent, the residue was chromatographed (silica gel) with CH2Cl2:CHCl3
(2:2.5) as an eluent to give a dark green product; Yield 71 %; green powder; m.p. >300oc;
1
IR (KBr) ύ/cm-1: 3419 (NH), 1724 (C=O), 1612 (C=N), 1554 (C=C), 750 (C-Cl); H
NMR (DMSO-d6) δ (ppm): 3.55 (s, 2H, 2NH). 13C NMR (DMSO-d6) δ (ppm): 131.3,
134.3, 140.7, 148.9, 155.2, 164.7, 167.2, 178.9, 187.0.MS: m/z (%): 912 (M++2, 50), 910
(M+, 40), 877 (70), 862 (44), 792 (50), 756 (45), 672 (60), 495 (52), 452 (49), 128 (53),
62 (80). UV-vis. spectrum: λmax(nm)/logε 680/ 4.656 nm. Anal.Calcd. for C32H2N8O8Cl8
(910.02): C, 42.24 ; H, 0.22; N, 12.31%. Found: C, 42.13; H, 0.22; N, 12.28%.
2.3. Synthesis of 1,4-Dioxo-1,4-dihydro-pyrido[1,2-a]indolo-2,3,10-tricarbonitrile (4)
A mixture of an equimolar ratio of DDQ (0.68 gm, 3 mmol) and 2-pyridinylacetonitrile
(3) (0.504 gm, 3 mmol) was refluxed in 20 ml ethanol containing a catalytic amount of
pyridine for 4 hrs until the reaction mixture was attained deep green to dark brown colour
at the end of reflux. The reaction mixture was filtered off while hot to remove the
unreacted materials and it was allowed to cool to room temperature, then poured onto ice
cold water. The precipitated solid was filtered off, washed several times with cold water,
dried, then recrystallized from a mixed solvent of acetone and ethanol (0.5:10 ml) to give
a brown product; Yield 85 %; brown powder; m.p 196 o C; IR (KBr) ύ/cm-1: 3065 (Ar-
13
CH), 2260 (C≡N), 2208 (C≡N of DDQ), 1725 (C=O), 1630 (C=N); C NMR (DMSO-
d6) δ (ppm): 85.9, 112.2, 115.8, 117.0, 117.2, 120.2, 124.0, 125.0, 134.8, 138.4, 146.2,
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175.2, 177.0. MS: m/z (%): 272 (M+, 30), 264(50), 196 (49), 158 (40), 106 (100), 78
(40). Anal.Calcd. for C15H4N4O2 (272.22): C, 66.18; H, 1.48; N, 20.58%. Found: C,
66.19; H, 1.43; N, 20.50%.
2.4. Synthesis of Tetra (10-cyano-1,4-dioxo-1,4-dihydropyrido[1',2':1,2]indolo[5,6-yl)
porphyrazine (5)
A mixture of dinitrile 4 (0.66 gm, 2 mmol) and n-propanol was heated for 3 hrs under
nitrogen gas, then a few crystals of iodine were added to initiate the reaction. Then, the
o
reaction mixture was further heated with stirring for 15 hrs. at 130 C. The reaction
mixture was filtered while hot and the residue was washed with CHCl3. The combined
organic layer was evaporated under vacuum and the resulting solid was chromatographed
(CHCl3: MeOH: NH4OH) (3:1.5:0.5).
Yield 55 %; deep green powder; m.p. >300oC; IR (KBr) ύ/cm-1: 3354 (NH), 3065 (=CH),
2240 (C≡N), 1730 (C=O), 1630 (C=N), 1559 (C=C); 1H NMR (CDCl3) δ (ppm): 3.54 (s,
2H, 2 NH), 7.02-7.42 (m, 16H, Ar-H), 9.31 (d, 4H, C2-H pyridine).13C NMR (DMSO-d6)
δ (ppm): 131.329, 134.391, 140.787, 148.929, 155.886, 164.786, 167.176, 178.097,
187.517. UV-vis. spectrum: λmax(nm) / logε 744/ 4.695 nm. Anal. Calcd.for C60H18N16O8
(1090.91): C, 66.06; H, 1.66; N, 20.54%. Found: C, 66.10; H, 1.66; N, 20.48%.
2.5. Synthesis of 2,5,8-trioxo-2,3,5,8-tetrahydro-1H-benzofuro[2,3-d]imidazole-6,7-
dicarbonitrile
(8)
4,7-dioxo-3-phenyl-4,7-dihydrobenzofuro[3,2-d]isoxazole-5,6
dicarbonitrile (9)
General procedure:
A mixture of an equimolar ratio of 2,3-dichloro-4,5-dicyano-p-benzoquinone (DDQ) (1)
(0.68 gm, 3 mmol) and imidazolidine-2,4-dione (6) (0.613 gm, 3 mmol) and/or 3-phenyl-
isoxazol-5-one (7) (0.522 gm, 3 mmol) was refluxed in 20 ml ethanol containing a
catalytic amount of pyridine (4 drops) for 4 hrs until the reaction mixture was attained
5

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deep green to blackish brown colour at the end of reflux. It was filtered while hot to
remove the unreacted materials and allowed to cool to room temperature, then poured
onto ice cold water. The precipitated solid was filtered off, washed several times with
cold water, dried, then recrystallized from a mixed solvent of acetone and ethanol in
molar ratio (0.5:10 ml) to give a brown product.
o
Compound (8); Yield 77 %; brown powder; m.p 152 C; IR (KBr) ύ/cm-1: 2208, 1685,
1
1640, 1610, 1110 corresponding to 2 C≡N, 2 C=O, C=N, C-O-C respectively; H NMR
(DMSO-d6) δ (ppm): 9.10 (s, 2H, 2NH). 13C NMR (DMSO-d6) δ (ppm): 115.9 (2C≡N),
119.1 (C=), 137 (C=), 138.5 (C=C), 151.9 (C-O), 156.2 (C=O), 160.1 (O-C), 169.9 (C=O
quinone), 175.1 (C=O quinone). MS: m/z (%): 254 (M+, 30). Anal. Calcd. for C11H2N4O4
(254.16): C, 51.98; H, 0.79; N, 22.04 %. Found: C, 51.87; H, 0.69; N, 21.89 %.
Compound (9); Yield 80 %; m.p 102 o C; IR (KBr) ??/cm-1: 2208 (2 C≡N of DDQ),
13
1685, 1640 (C=O), 1620 (C=N), 1110 (C-O-C). C NMR (DMSO-d6) δ (ppm): 100.5,
115.8, 127.5, 128.7, 129.2, 131.5,138.4, 140.5, 154.6,158.9, 160.6, 170.0, 175.2. MS: m/z
(%): 315 (M+, 46), 274 (20), 259 (30), 234 (25), 207 (32), 179 (100), 153 (34), 113 (40),
113 (42), 89 (29), 63 (24). Anal. Calcd. for C17H5N3O4 (315.24): C, 64.77; H, 1.6; N,
13.33%. Found: C, 64.81; H, 1.70; N, 13.41%
2.6. Synthesis of Tetra (2,5,8-trioxo-1, 3-dihydro-benzofuro[2,3-d]imidazole-6,7-yl)
porphyrinazine
(10)
and
tetra(4,7-Dioxo-3-phenyl-4,7-dihydro-benzofuro[3,2-
d]isoxazole-5,6- 5,6-yl)porphyrinazine (11)
General procedure:
Compound (10); Yield 40 %; deep green powder; m.p. >300 o C; IR (KBr) ύ/cm-1: 3341
(NH), 1685 (C=O amidic), 1645 (C=O), 1624 (C=N). 1H NMR (DMSO-d6) δ (ppm): 9.1
(s, 8H, NH), 11.9 (s, 2H, NH). 13C NMR (DMSO-d6) δ (ppm): 119.1, 137.0, 138.2, 151.9,
152.6, 155.2, 160.7, 170.0, 175.0. UV-vis. spectrum: λmax(nm) / logε 740/ 4.697 nm.
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Anal.Calcd.for C44H10N16O16 (1018.66): C, 51.88; H, 0.99; N, 22.00%. Found: C, 51.69;
H, 1.00; N, 21.89%.
Compound (11); Yield 35 %; m.p. >300 o C; IR (KBr) ύ/cm-1: 3341 (NH), 3065 (=CH),
1728 (C=O), 1624 (C=N).13C NMR (DMSO-d6) δ (ppm): 100.5, 119.1, 127.5, 128.7,
129.2, 131.8, 138.2, 140.5, 152.6, 154.6, 158.9, 161.6, 170.0, 175.0. UV-vis. spectrum:
λmax(nm) /logε 748/ 4.697 nm. Anal. Calcd. for C68H22N12O16 (1262.99): C, 64.67; H,
1.76; N, 13.31%. Found: C, 64.63; H, 1.63; N, 13.42 %.
2.7.
Synthesis
of
Synthesis
of
N,N'-(pyridine-2,3-diyl)bis(4-
methylbenzenesulfonamide) (12)
A pure crystalline sample of bimolar ratio of p-toluenesulfonyl chloride (3.80 gm, 20
mmol) and an equimolar ratio of 2,3-diaminopyridine (1.08 gm, 10 mmol) was stirred in
ethanol (20 ml) containing a catalytic amount of pyridine for 6 hrs. The reaction mixture
was changed from pale red to deep red colour at the end of the stirring. It was filtered to
remove the unreacted materials. Evaporization of solvent until half of its volume gave a
o
colourless needle crystal; Yield 95 %; colourless needle crystal; m.p 198 C; IR (KBr)
1
ύ/cm-1: 3270 (NH), 2952 (CH3), 1320 (SO2); H NMR (DMSO - d6): δ (ppm):δ 2.39 (s,
6H, 2 CH3), 7.22 (d, 4H, 4 Ar-CH), 7.38 (d, 4H, 4 Ar-CH), 7.51- 7.91 (m, 3H, Py-H),
13
10.12 (s, 1H, NH), 11.32 (s, 1H,NH). C NMR (DMSO-d6) δ (ppm): 21.3(CH3), 128.3,
129.4, 136.5, 137.1 (benzene ring), 114.2, 122.7, 123.4 (Pyridine ring). MS: m/z (%): 417
(M+, 25), 386 (48), 326 (40), 247 (100), 231 (39), 171 (50), 155 (40), 77 (52). Anal.
Calcd. for C19H19N3O4S2 (417.50): C, 54.66; H, 4.59; N, 10.06%. Found: C, 54.46; H,
4.60; N, 10.08%.
2.8. Synthesis of 6,9-dioxo-5,10-ditosyl-5,6,9,10-tetrahydropyrido[2,3-b]quinoxaline-
7,8-dicarbonitrile (13)
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A mixture of a pure crystalline sample of compound 12 (1.25 gm, 3 mmol) and 2,3-
dichloro-4,5-dicyano-p-benzoquinone (DDQ) (0.68 gm, 3 mmol) was refluxed in
absolute ethanol (20 ml) containing a catalytic amount of pyridine for 4-5 hrs under
nitrogen gas. The reaction mixture was changed from pale red to deep brown colour at
the end of reflux. The reaction mixture was then filtered while hot to remove the
unreacted materials, then poured onto ice-cold water. The crude product was collected by
filtration, dried well, then recrystallized by ethanol; Yield 75 %; brown powder; m.p >
o
300 C; IR (KBr)ύ/cm-1: 3058 (Ar CH), 2925-2850 (CH3), 2208 (broad band of C≡N),
1726 (C=O), 1612 (C=N), 1300-1150 (SO2); 1H NMR (DMSO - d6) δ (ppm): 2.39 (s, 6H,
13
2 CH3), 7.22 (d, 4H, 4 Ar- CH), 7.38 (d, 4H, 4 Ar-CH), 7.51-7.91 (m, 3H, Py-H). C
NMR (DMSO-d6) δ (ppm): (benzene ring), 121.3, 129.1, 130.1, 130.3, 136.5, 137.2,
(pyridine ring), 114.2, 122.7, 137.5, 149.3, (quinone ring), 148.1, 128.0, 187.0, (C≡N)
110.3. MS: m/z (%) 571 (M+, 24), 544 (40), 516 (100), 423 (30), 347 (46), 259 (52), 105
(53). Anal. Calcd. For C27H17N5O6S2 (571.58):C, 56.74; H, 3.00; N, 12.25%. Found: C,
56.88; H, 3.05; N, 12.42%.
2.9.
Synthesis
of
tetra(6,9-dioxo-5,10-ditosyl-5,6,9,10-tetrahydropyrido[2,3-
b]quinoxaline-7,8- yl)porphyrazine (14)
A mixture of compound 13 (1.14 gm, 2 mmol) and 1,4-diazabicyclo[2.2.2]octane
(DBO) was flushed with nitrogen gas and heated at 200 ˚C for 30 min, then 25 ml of
ethylene glycol was added. The mixture was continued heating with stirring under
nitrogen gas at 150 ˚C for 10 hr. After removing the solvent, the residue was
chromatographed (silica gel) with CH2Cl2:CHCl3 (2:1.5) as an eluent to give a dark
green product; Yield 64 %; dark green powder; m.p. >300 ˚C; IR (KBr) ύ/cm-1: 3350
1
(NH), 1612 (C=N), 1554 (C=C), 1300-1150 (SO2); H NMR (DMSO - d6) δ (ppm):
2.30 (s, 24 H, 8 CH3), 3.52 (s, 2H, 2 NH), 6.15 (d, 16H, 16 Ar-CH), 6.30 (d, 16H, 16
8

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Ar-CH), 7.25-7.58 (m, 12H, Py-H). 13C NMR (DMSO-d6) δ (ppm): 24.5, 117.2,
119.6, 127.3, 129.5, 131.2, 132.4, 134.1, 135.0, 139.8, 141.0, 141.2, 155.2, 164.5,
168.2, 174.2, 177.9. UV-vis. spectrum: λmax(nm) / logε 735/4.698 nm. Anal. Calcd. for
C108H70N20O24S8 (2286.26): C, 56.69; H, 3.08; N, 12.24%. Found: C, 56.51; H,
3.11; N, 12.28 %
2.10. Synthesis of phthalocyanine derivatives 17 and 21a, b.
2.10.1. General procedure:
Phthalic anhydride derivatives 15 and/ or 20a, b (0.68 mmol), urea (0.122 g, 2.04 mmol)
and 1,3-divinyl-1,1,3,3-tetramethyldisilazane (16) (0.49 g, 2.7 mmol) were mixed in dry
DMF in a round bottomed flask equipped with a reflux condenser. The reaction mixture
was heated at 150 ˚C under nitrogen gas for 10 hr. A dark green solid immediately
appeared and was filtered in pump. The solid was washed with methanol and then
dissolved in concentrated sulphuric acid (5 mL). The solution was then poured into water
(100 mL). The resulting green precipitates were filtered off and washed successively with
dilute sulphuric acid, water and methanol. The solid product was further purified by
column chromatographic technique (silica gel) (CHCl3: hexane) (2:1.5) to give
compounds 17 and 21a, b, respectively.
2.10.1.1. Synthesis of Tetra (pyrido-2,3-yl) porphyrinazine (17)
Yield 57 %; blue crystals; m.p. >300 oC; IR (KBr) ύ/cm-1: 3302 (NH), 1622 (C=N),
1554 (C=C); 1H NMR (DMSO-d6) δ (ppm): 7.10 (s, 1H, NH), 7.60-8.11 (m, 12H, Ar-
13
H), 9.62 (s, 1H, NH). C NMR (DMSO-d6) δ (ppm): 109.2, 117.00, 122.60, 124.3,
126.30, 126.81, 129.63, 129.72, 135.9, 134.40, 136.30, 141.00, 149.70, 150.60,
151.40, 153.00, 168.0, 169.7, 171.4. MS: m/z (%): 520 (M+,50), 506 (59), 480 (75),
466 (95), 404 (64), 390 (26), 376 (29), 261 (24), 247 (100), 224 (46), 195 (50), 171
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(48), 145 (23) 119 (16). UV-vis. spectrum: (λmax) / (ξ), 680 nm / 5.13. Anal. Calcd. for
C28H14N12 (518.15): C, 64.86; H, 2.72; N, 32.42 %. Found: C, 62.84; H, 2.70; N,
32.40 %.
2.10.1.2. Synthesis of 2,3,9,10,16,17,23,24-Tetra[1-((8-(phenoxy-2,3-yl)quinolin-5-
yl)diazenyl)naphthalen-2-ol]phthalocyanine (21a)
Yield 59%; green crystals; m.p. >300 oC; IR (KBr) ύ/cm-1: 3352 (NH), 1612 (C=N),
1554 (C=C), 1210 (C-O-C); 1H NMR (DMSO-d6) δ (ppm): 5.62 (s, 1H, NH), 7.32 (d,
J= 7.0, 4H, 4CH), 7.47 (d, J= 7.0, 4H, 4CH), 7.58 (d.d, J= 6.9, 4H, 4CH), 7.65 (d.d,
J= 6.8, 4H, 4CH), 7.77 (d.d, J= 6.8, 4H, 4CH), 7.89 (d, J= 6.8, 4H, 4CH), 8.08 (d, J=
6.7, 4H, 4CH), 8.55 (d, J=6.8, 4H, 4CH), 8.89 (d, J= 6.8, 4H, 4CH) 11.94 (s, 1H,
NH). UV-vis. spectrum: (λmax) / (ξ), 682 nm / 5.13. Anal. Calcd. For C108H62N20O8
(1766.51): C, 73.38; H, 3.54; N, 15.85%. Found: C, 73.16; H, 3.55; N, 15.60 %.
2.10.1.3. Synthesis of 2,3,9,10,16,17,23,24-Tetra[1-((8-(phenoxy-3,4-yl)quinolin-5-
yl)diazenyl)naphthalen-2-ol] phthalocyanine(21b)
Yield 53%; green crystals; m.p> 300 ˚C; IR (KBr)ύ/cm-1: 3343 (NH), 1725 (C=O), 1685
1
(C=O), 1611 (C=N), 1559 (C=C); H NMR (DMSO-d6) δ (ppm): 7.32 (d.d, J= 8.8, 4H,
4CH), 7.52 (d.d, J= 7.8, 4H, 4CH), 7.82 (d, J= 8.0, 4H, 4CH), 8.01 (d, J= 8.1, 4H, 4CH),
8.19 (d, J= 7.8, 4H, 4CH), 8.32 (d, J= 7.3, 4H, 4CH), 8.72 (d.d, J= 7.1, 4H, 4 CH); 8.90
(s, 2H, 2NH), UV-vis. spectrum: (λmax)/ (ξ), 676 nm / 5.13. Anal. Calcd. for
C108H62N20O8 (1766.51): C, 73.38; H, 3.54; N, 15.85%. Found: C, 73.21; H, 3.75; N,
15.35 %.
2.11. Synthesis of phthaleic anhydride derivatives 20a, b.
2.11.1. General procedure:
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A mixture of 3- and/or 4-nitrophthalic anhydride 18a, b (0.97 g, 5 mmol), 5-(2-hydroxy
naphthalene-1-yl) diazeneyl) quinolin-8-ol (16) (0.715 g, 5 mmol) and anhydrous
potassium hydroxide pellets (0.42 g, 7.5 mmol) was refluxed with stirring in dry DMF
(20 mL) at 250 ˚C under N2 gas. The reaction mixture colour was changed at the end of
reflux. It was allowed to cool to room temperature, then poured onto ice blocks (200 mL)
and neutralized with conc. HCl to give a precipitate which was collected by filtration,
washed with water and dried. The crude product was purified by recrystallization with
CH2Cl2: EtOH (5:20 mL) to afford brown precipitates of compounds 20a, b, respectively.
2.11.1.1. Synthesis of 4-[5((2-Hydroxy-naphthalen-1-yl)diazenyl)-quinolin-8-yl)oxy]-
isobenzofuran-1,3-dione (20a)
o
Yield 65%; deep brown powder; m.p 58 C; IR (KBr) ύ/cm-1: 3095 (Ar-CH), 1732
13
(C=O), 1689 (C=O), 1550 cm-1 (N=N). C NMR (DMSO-d6) δ (ppm): (anhydride
ring) 121.5, 136.2, 129.3, 122.6, 139.0, 155.5, 162.3, (quinoline ring) 112.5, 122.0,
124.9, 137.2, 137.7, 144.3, 154.9, 150.1 (α- naphthol ring) 123.0, 126.8, 127.7, 126.0,
129.3, 129.5, 128.0, 123.7, 145.3, 156.2. MS: m/z (%) 461 (M+, 24), 292 (50), 263
(37), 247 (27), 219 (30), 193 (100), 172 (24), 179 (40), 167 (30), 153 (39), 127 (35),
117 (42), 77 (43), 64 (23). Anal. Calcd. for C27H15N3O5 (461.1): C, 70.28; H, 3.28; N,
9.11%. Found: C, 70.11; H, 3.13; N, 9.05 %.
2.11.1.2. Synthesis of 5-[(5(2-Hydroxy-naphthalen-1-yl)diaazenyl)quinolin-8-yl)oxy]-
isobenzofuran-1,3-dione (20b)
Yield 71%; reddish brown powder; m.p 230oC; IR (KBr) ύ/cm-1: 3105 (Ar-H), 1732,
1725, 1689 and 1630 (4 C=O), 1555 (N=N). MS: m/z (%): 461 (M+, 70), 295 (43), 267
(35), 239 (87), 223 (100), 195 (34), 169 (33), 141 (28), 120 (26), 117 (46), 78 (69), 68
(28). Anal. Calcd. for C27H15N3O5 (461.1): C, 70.28; H, 3.28; N, 9.11%. Found: C,
70.14; H, 3.10; N, 8.92 %.
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2.12. Synthesis of 2,9-bis(2-hydroxy ethyl)anthra[2,1,9 -def:6,5,10- dʹeʹfʹ]
diisoquiuoline-1,3,8,10 (2H, 9H)tetraone (23)
A mixture of perylene dianhydride (1.36g, 4 mmol), ethanolamine (0.488g, 8mmol)
and sodium acetate (1g) was heated in pressure tube at 150 ˚C in silicon oil for 2hrs.
The mixture was left to cool at room temperature and recrystallized from a mixture of
ethanol : DMF (2 : 1) to give compound 23; Yield 85%; m.p> 300 oC; IR (KBr) ύ/cm-
1: 3450 (OH), 1685 (C=O).1H NMR (DMSO-d6) δ (ppm): 3.40 (t- 2H, N-CH2), 3.66 (t,
13
2H, O-CH2), 7.84 (d, 4H, Ar-H), 8.20 (d, 4H, Ar-H), 13.85 (s, 1H, OH), C NMR
(DMSO-d6) δ (ppm): 44.2 (N-C), 58.3 (O-C), 124.2, 130.0, 135.7, 160.0 (C=O). MS
m/z (%): 478 (M+, 40%). Anal. Calcd. for C28H18N2O6 (478.46): C, 70.29; H, 3.79; N,
5.86%. Found: C, 70.16; H, 3.67; N, 5.80 %.
2.13.
Synthesis
of
2,9-bis[2-((1,3-dioxo-1,3-dihydro
isobenzofuran-5-
yl)oxy)ethyl)anthra[2,1,9-def : 6,5,10- dʹeʹfʹ] diisoquiuoline- 1,3,8,10- (2H, 9H)tetraone
(24)
It was prepared according to the previously mentioned procedure for the synthesis of
o
compounds 20a, b. Yield 65%; m.p > 300 C; IR (KBr) ύ/cm-1: 1696 and 1680 (2
C=O); 1H NMR (DMSO-d6) δ (ppm): 3.64 (t- 2H, N-CH2), 4.34 (t, 2H, O-CH2), 7.48
(d, 2H, Ar-H), 7.78 (d, 4H, Ar-H), 7.98 (s, 2H, Ar-H), 8.13 (d, 2H, Ar-H), 8.22 (d, 4H,
Ar-H). MS: m/z (%): 770 (M+, 35%). Anal. Calcd. for C44H22N2O12 (770.66): C, 68.58;
H, 2.88; N, 3.64%. Found: C, 68.50; H, 2.81; N, 3.61%.
2.14. Synthesis of phthalocyanine polymer 25
In a round bottomed flask equipped with a reflux condenser, the mixture of perylene
diimide (24) (0.385 g, 5 mmol), urea (0.244 g, 4.08 mmol) and 1,3-divinyl-1,1,3,3-
tetramethyldisilazane (16) (0.99 g, 5.4 mmol) was mixed in dry DMF. After that, it
was heated at 150 ˚ C under nitrogen gas. A dark coloured solid immediately appeared
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and was filtered. The solid was washed with methanol and then dissolved in
concentrated sulfuric acid (5 mL). The solution was then poured into water (100 mL).
The resulting precipitates were filtered and washed successively with dilute sulfuric
acid, water and methanol. The solid was further purified by a column chromatographic
technique (silica gel) (CHCl3: hexane: MeOH) (2:1.5:0.5) as eluent; Yield 61%;
intense red powder; m.p. >300 ˚ C; IR (KBr) ύ/cm-1: 3350 (NH), 3030 (Ar-CH), 1636,
1623 (C=N), 1610 (C=C); UV-vis. spectrum: (λmax) / (ξ), 675 nm / 5.13.
3.
Biochemical assays:
3.1. Antioxidant properties:
Biological methods: Free radical scavenging activity of tested compounds was evaluated
by measuring their ability to neutralize DPPH and OH radicals.
DPPH assay: The DPPH (2,2-diphenyl-1-picrylhydrazyl) assay was used as the reported
literature [16]. The different aliquots (0.1–2 mL) of 0.01 M sample solution in methanol
were added to1 mL of 90 ꢀM DPPH• in methanol and filled up with 95 % (v/v) methanol
to a final volume of 4 mL. Another reaction mixture under the same condition and
without tested compound was used as the control. Absorbance of the reaction mixtures
and control was recorded at 515 nm after 1 h. Commercial synthetic antioxidants, BHT
and BHA, were used as positive controls. For each sample, three replicates were
recorded. DPPH scavenging activity was expressed as radical scavenging activity (DPPH
RSC). The percentage of DPPH RSC was calculated using the following equation:
RSC (%) = (Ablank – Asample /Ablank) X 100
Where A blank is the absorbance of control (1·10−4 mol dm−3 DPPH methanol solution),
and A sample is the absorbance of the test sample, IC50 values (the concentration of the
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tested compound in the reaction mixture that causes 50% of RSC) were determined by
linear regression analysis from the obtained RSC values.
Hydroxyl-radical scavenging assay: Hydroxyl-radical scavenging capacity (HO• RSC)
of the tested compounds was characterized by determining the degradation of 2-deoxy-D-
ribose by OH radicals, formed in situ in Fenton’s reaction [16]. These radicals react with
sugar 2-deoxy-D-ribose and degrade it into a group of fragments, some or all of which
react on heating with 2-TBA at low pH to produce a pink chromogen, which can be
determined by spectrophotometric method at 532 nm. Different aliquots (0.005–0.5 mL)
of sample solution in methanol were added to test tubes (final concentration ranged
between 0.01 and 8 mM), each containing 0.1 mL of 5 mM H2O2, 0.1 mL of 10 mM
FeSO4 and 0.1 mL of0.05 M 2-deoxy-D-ribose and 0.067 M KH2PO4-K2HPO4 buffer pH
7.4 to a final volume of 3 mL. Another reaction mixture under the same condition and
without sample was used as the control. After an incubation period of 1 h at 37 °C, 2 mL
of TBA reagent (10.4 mL of 60% (v/v) HClO4, 3 g TBA and 120 g of trichloroacetic
acid, and0.2 mL of 0.1 M EDTA were added to the reaction mixture, and the tubes were
heated at 100°C for 20 min. After cooling, absorbance of the reaction mixtures and
control was recorded at 532 nm. Percentage of HO• RSC was calculated using the
following equation:
RSC (%) = (Ablank – Asample /Ablank) X 100
Three replicates were recorded for each sample; BHT and BHA were used as reference
compounds.
3.2. Cytotoxicity and antitumor assay:
14

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Samples were prepared for assay by dissolving test dyes in 50 µL of DMSO and diluting
aliquots into sterile culture medium at 0.4 mg/mL. These solutions were sub-diluted to
0.02 mg/mL in sterile medium and the two solutions were used as stocks to test samples
at 100, 50, 20, 10, 5, 2, and 1 mg/mL in triplicate in the wells of microtiter plates. The
tested dyes were assayed in triplicate on monolayers grown in Dulbecco’s modified
Eagle’s medium supplemented with 10% v/v calf serum (Hyclone Laboratories, Ogden,
UT), 60 mg/mL pencillin G and 100 mg/mL streptomycin sulfate maintained at 37 ˚C in a
humidified atmosphere containing about 15% v/v CO2 in air. All medium components
were obtained from Sigma Chemical Co., St. Louis, MO, unless otherwise indicated. Cell
stocks were maintained at 34 ˚C in culture flasks filled with medium supplemented with
1% v/v calf serum. Subcultures of cells for screening were grown in the wells of
microtiter trays (Falcon Microtest III 96-wells trays, Becton Dickinson Labware, Lincolin
Park, NJ) by suspending cells in medium followed by trypsin-EDTA treatment, counting
the suspension with a hemocytometer, diluting in medium containing 10% calf serum to
2* 104 cells per 200 mL culture, aliquoting into each well of a tray and culturing until
confluent. Microtiter trays with confluent monolayer cultures of cells were inverted, the
medium was shaken out and replaced with serial dilutions of sterile dyes in triplicate in
100 µL medium followed by titered virus in 100 µL medium containing 10% v/v calf
serum in each well. In each tray, the last row of wells was reversed for controls that were
not treated with dyes. The trays were cultured for 96 h. The trays were inverted onto a
pad of paper towels. The remaining cells were rinsed carefully with medium and fixed
with 3.7% v/v formaldehyde in saline for at least 20 min. The fixed cells were rinsed with
water and examined visually. The cytotoxic activity is identified as confluent, relatively
unaltered monolayers of stained cells treated with compounds. Cytotoxicity was
15

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estimated as the concentration that caused approximately 50% loss of the monolayer.
[17]. 5-Fluorouracil was used as a positive control [18].
4.
Results and discussion
Chemistry
4.1.
A great deal of effort has been made to study the optical properties of phthalocyanines
and associated compounds. Because of the very good optical absorption of these
molecules in the UV-vis region, there is a considerable interest in the characterization of
the electronic structure of phthalocyanines. In the case of higher cyclic oligomers, the
design of the suggested symmetrical hexa-deca substituted phthalocyanine requires the
phthalonitrile precursors which are crucial for creation of fully substituted materials with
desired properties. Moreover, numerous halogenated (F, Cl) organic compounds are
soluble in most organic solvents and have various bioactivities which render them as
valuable active ingredients [19-21]. Thus, it was found that 2,3-dichloro-5,6-dicyano-1,4-
benzoquinone (DDQ) (1) was firstly fused with hydroquinone at 200 ˚C under nitrogen
gas for about 10 hrs, route (A). It gave a deep green product 2 analyzed as C32H2N8O8Cl8
corresponding to phthalocyanine structure 2 which showed a UV-vis spectrum band at
λmax = 680 nm and a molecular ion peak at m/z = 912 (M+ + 2, 50 %) in its mass spectrum
(Scheme 1). Also, it was more confirmed by 13C-NMR as outlined in experimental
section. The same reaction when repeated by route (B) in which 1 was fused with 1,4-
o
diazabicyclo[2.2.2]octane (DBO) at 200 C, then ethylene glycol was added and the
reaction was continued heating for about 10 hrs. under nitrogen gas, they gave identical
product in all respects (IR, UV, 13C NMR & MS) to 2. Yield was improved from 35% in
case of route (A) to 71% in case of route (B) (Scheme 1). The reaction may be proceeded
according to the proposed mechanism (Scheme 2, supplementary information file).
16

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<Scheme 1>
The precursor 1,4-dioxo-1,4-dihydropyrido[1,2-H]indole-2,3,10-tricarbonitrile (4) was
easily prepared and purified (supplementary information file)
The novel phthalonitrile 4 was dissolved in dry n-propanol by heating at a boiling
temperature for 3 hrs. under N2 gas, and then a few crystals of iodine were added to
initiate the reaction. The reaction mixture was refluxed for further 15 hrs. to give the
corresponding deep green phthalocyanine 5 (Scheme 4).
<Scheme 4>
In this model, structure 5 was confirmed by its correct analytical data. The IR spectrum
revealed absorption bands at ύ 3354, 3065, 2240, 1730 and 1630 cm-1 due to NH, olefinic
CH, C≡N, C=O and C=N, respectively. The 13C-NMR showed an excellent elucidation of
structure 5. The UV-Vis spectrum of compound 5 showed a band centered at λmax = 744
nm (Q band).
The new imidazolo and isoxazolodicarbonitriles 8 & 9 (supplementary information file,
Scheme 5A) when heated with hydroquinone at 200˚C under N2 gas, they afforded the
corresponding phthalocyanine derivatives 10 & 11, respectively, in 40-35 % yield. The
IR spectra of 10 & 11, in general, showed the disappearance of C≡N absorption bands in
the region 2220 cm-1. This is evidence of cyclotetramerization of dinitrile compounds 8 &
9. Also, they showed the intense absorption bands at ύ 3341, 1685, 1645 and 1624 cm-1
corresponding to NH, amidic and α, β- unsaturated ketonic C=O and C=N functional
groups, respectively. The 1H-NMR spectrum of 10 displayed two singlet signals at δ 9.1
and 11.9 ppm corresponding to NH (imidazolo) and endocyclic NH, respectively. The Q
band absorption data was obtained for representative compound in DMF at λmax = 740 nm
(Scheme 5B).
<Scheme 5B>
17

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Starting from the new dicyano derivative 13 (supplementary information file), many
chemical routes may be used to form the corresponding metal-free phthalocyanine 14.
Metal-free phthalocyanine 14 was synthesized by heating the corresponding dicyano
compound 13 with DBO, and then ethylene glycol was added and heating was continued
for 10 hrs. The IR spectrum of metal-free phthalocyanine 14 showed absorption band at
3350 cm-1 for NH vibrations. The disappearance of the C≡N stretching vibration in the IR
spectrum suggested the formation of compound 14. The 13C-NMR showed the
disappearance of a signal at δ 110.1 ppm due to the C≡N group which gave an additional
confirmation of its correct structure. The UV-vis spectrum showed an absorption band at
λmax = 735 nm corresponding to Q-band (Scheme 7).
<Scheme 7>
Moreover, we now report a successful use of disilazane derivatives in the preparation of
new phthalocyanines under a mild condition. As a continuation of our effort to identify
new candidates, the above-mentioned findings may be of a good value in designing new,
potent, selective, and less toxic photosensitizers. Significantly, the synthetic strategies
were adopted for the synthesis of a series of free metallated phthalocyanine as outlined in
(Scheme 8, 10 & 12). Therefore, metal-free phthalocyanine (17) was prepared by heating
quinolinic anhydride derivative 15 with 1,3-divinyl-1,1,3,3-tetramethyldisilazane (16) in
the presence of urea for prolonged time which has a capability to improve the yield. The
role of urea is to convert the acid anhydrides to their corresponding acid imide derivatives
and activate the disilazane to promote the formation of the phthalocyanine frameworks
(Scheme 8).
<Scheme 8>
The UV-vis absorption spectrum of the metal-free phthalocyanine 17 showed
characteristic Q and B bands. Phthalocyanine which contains phthalimide moiety 17
18

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exhibited typical electronic spectra with two strong absorption regions: one in the visible
region (red region) at λmax= 600-700 nm (Q-band) and the other in the UV region (blue
region) at λmax = 300-350 nm (B band) (Fig. 2) . Both of these spectral features are
attributed to π- π* transition and described by the Gouterman four orbital model (Fig. 3)
[17, 22- 24] (supplementary information file).
<Figure 2>
It has been reported that phthalocyanines have unique light absorption in the far visible
region of the solar spectrum (λ = 690 nm) and molecular extinction coefficients (ε) more
than 100,000 dm3 M–1 cm–1 and a good chemical stability [25- 27]. Phthalocyanines 2, 5,
10, 11, and 14 showed typical electronic spectra with two different strong absorption
regions. Firstly, a UV region at around 340 nm called the soret or B band, arising from
the deeper by π-levels → LUMO transition between an a2u and the same eg orbitals and
extending to the green of the visible region at λmax= 600-750 nm called the Q-band, is
attributed to the π- π* transition from the HUMO to the LUMO of the Pc-2 ring [28, 29].
The purity and depth of color of phthalocyanines arising from an isolated Q-band at the
far-red end of the visible spectrum of the metal-free in N, N-dimethylformamide at room
temperature are shown in (Fig.1). The UV spectra of compounds 10 &11 are very similar
to each other and represented as one peak. The metal-free phthalocyanines showed that
the Q-band appeared as intense peaks at λmax= 680, 744, 740, 735 and 748 nm. The low ε
of cell incorporating phthalocyanines might be due to the poor solubility of the
macrocycle in organic solvents, and a strong tendency to aggregate on the film surface,
resulting in a rapid deactivation of the dye excited state.
In order to further improve the overall efficiency of Pc's, one has to increase the molar
extinction coefficient (ε) of the Q-band absorption of phthalocyanine macrocycle. During
the course of our research work on the development of phthalocyanine based dyes, we
19

ACCEPTED MANUSCRIPT
have realized that introduction of extended π-conjugation can increase the ε of the
absorption bands of phthalocyanine macrocycle owing to enhancing the solubility of
phthalocyanine in common organic solvents, reduce the aggregation and tune the lowest
unoccupied molecular orbital (LUMO) level of phthalocyanine regarding to electron
pushing feature of extended π-conjugated system.
<Figure 1>
The cyclotetramerization of phthalic anhydride derivatives 20a & b (supplementary
information file) was performed in refluxing N, N-dimethylformamide in the presence of
urea and disilazane 16 according to the previously mentioned condition. Thus, we
decided to synthesize metal-free phthalocyanines 21a & b (Scheme 10).
<Scheme 10>
UV-vis absorption spectra of the metal-free phthalocyanines 21a, b in N, N
dimethylformamide exhibited the split Q-band [32- 35] which is a characteristic of metal-
free phthalocyanines 21a, b at λmax= 682 and 676 nm, respectively (Fig. 2).
Furthermore, in the present work, we report here the synthesis and characterization of
metal-free phthalocyanine polymers 25 achieved by heating phthalic anhydride derivative
24 with disilazane derivative 16 in the presence of urea according to the previously
mentioned reaction condition (Scheme 11 & 12). Phthalic anhydride derivative 24 was
synthesized by fusion of 3,4.9,10-perylenetetracarboxylic dianhydride (22) with
ethanolamine in silicon oil at 150 ˚C for 2 hrs to give the corresponding diimide 23. The
IR spectrum of 23 showed absorption bands at ύ 3450 and 1685 cm-1 due to C=O
1
function groups. The H-NMR spectrum displayed two triplets at δ 3.40 and 3.66
corresponding to two CH2 groups and singlet a signal at δ 13.85 ppm due to OH proton.
The diimide 23 was then subjected to react with 4-nitrophthalic anhydride in DMF in the
presence of potassium hydroxide under nitrogen gas to give the corresponding phthalic
20

ACCEPTED MANUSCRIPT
anhydride derivative 24. Structure 24 was confirmed by both analytical and spectral data.
The IR spectrum showed two characteristic absorption bands at ύ 1696 and 1685 cm-1
due to two types of C=O groups. The IR spectral data clearly indicated the formation of
compound 25 by the disappearance of the carbonyl bands of dianhydrides at ύ 1680 &
1696 cm-1 and the appearance of new absorption bands at 1623 &1636 cm-1 due to C=N.
The UV-vis spectrum showed characteristic Q and B bands at regions of λmax=675 and
355 nm, respectively (Fig.2). The characteristic Q bands of all metal-free
phthalocyanines are represented in (Table 1).
<Scheme 11>
<Scheme 12>
<Figure 2>
4.2.Pharmacology
4.2.1. Antioxidant activities:
The antioxidant properties of the synthesized compounds 2, 4, 5, 8, 9, 10, 11, 13, 14, 17,
21a, 21b, 23, and 24 were investigated in a chain of in vitro tests. In the 2,2-diphenyl-1-
picrylhydrazyl (DPPH) assay, the behavior of tested compounds to donate protons or
electrons in converting DPPH• into its reduced form, DPPH-H, was measured by
spectrophotometric method [16]. All tested compounds reduced the stable, purple-colored
radical DPPH• into yellow-colored DPPH-H form (Table 2). Commercial synthetic
antioxidants, 3,5-di-tert-butyl-4-hydroxytoluene(BHT) and 3-tert-butyl-4-hydroxyanisole
(BHA) were used as positive controls. Compounds 13 and 14 showed the strongest
radical scavenging activity. The excellent free radical scavenging activity of compounds
13 and 14 may be because of the unique structure, which is rich in nitrogen atoms besides
sulfur atom. These results agreed with the reported literatures showing that the sulfur
21

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atom present in quinolone derivatives acts as a good radical scavenger [36]. The hydroxyl
radical scavenging activity of the synthesized compounds (Table 2) was measured by the
deoxyribose assay [16]. Protective effect of the new compounds was followed as they can
remove hydroxyl radicals from the tested solution and inhibit the degradation. High
prevention of degradation was observed for all tested compounds, especially for
compounds 13 and 14. Comparison of the IC50 values for the synthesized compounds
with the IC50 values for BHT and BHA indicates that 3-hterocyclylquinolinone skeletons
are very strong scavengers of OH radicals (generated in Fenton’s reaction). The
prevention of lipid peroxidation (LP) was characterized by determining the formation of
MDA, using liposomes as an oxidizable substance [16]. Some of the synthesized
compounds revealed notable inhibition of the Fe2+/ascorbate induced LP in liposomes.
Compounds 13 and 14 showed the highest inhibition. Comparison of the IC50 values for
the new compounds with the IC50 values for BHT and BHA shows that 13 and 14 could
be classified as very inhibitors of LP. As depicted in (Table 2), compounds 13 and 14
were the most active compounds in this assay showing a free radical scavenging activity
comparable to BHT and BHA. This was in excellent agreement with the previous
reported work that quinones are good antioxidants at lower concentration. [37]
<Table 2>
4.2.2. Cytotoxicity
The synthesized compounds were evaluated and screened for cytotoxic activity (Table 3)
against Vero (an African green monkey kidney cell line), WI-38 (lung fibroblast cell
line), HepG2 (hepatoma cells or human liver hepato carcinoma cell line) and MCF-7 cells
(human breast adenocarcinoma cell line) (Fig. 4) (supplementary information file).
Compound 14 exhibited the best cytotoxic activity against the HepG2 cell line, whereas
compounds 13, 10, 11, 21a and 21b exhibited a good cytotoxic activity against HepG2.
22

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Other compounds showed low activity against HepG2. By comparing the results of the
tested compounds with 14, we found that the sulfonyl group enhances the activity against
different cell lines. Also, compound 14 displayed the best cytotoxic activity against the
WI-38 cell line due to the presence of the sulfonyl group which revealed a more potent
activity. However, compound 13 exhibited moderate cytotoxicity owing to the presence
of chlorine atom in the ortho position for quinone, which acts as electron withdrawing
group, while the rest of the compounds showed a weak activity. Moreover, compounds
13 and 14 showed a moderate cytotoxic activity against the Vero cell line, whereas the
rest of compounds displayed the lowest cytotoxic activity against the Vero cell line.
Furthermore, compound 14 was found to exhibit an excellent ability for cytotoxic activity
against MCF-7 cells due to the presence of a sulfonyl group and rich in nitrogen atoms,
whereas compounds 13, 21a and 21b displayed a moderate cytotoxic activity against the
MCF-7 cell line. Finally, the rest of compounds exhibited the lowest cytotoxic activity
against the MCF-7 cell line. Further in vitro studies are warranted to confirm the
biological activity of the newly synthesized phthalocyanines and to investigate the
molecular mechanisms responsible for the antitumor activity at the most compounds with
a potential pharmaceutical use.
<Table 3>
5. Conclusion
In the present work, we reported a convenient synthesis of some new phthalonitrile and
phthalic anhydride derivatives and their synthetic utility as excellent precursors to get a
diversity of some new functionalized phthalocyanine derivatives in remarkable good
yield.
23

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Our aim of work was focused on the synthesis of biologically active phthalonitrile and
phthalic anhydride derivatives containing active heterocyclic moieties such as pyridine,
imidazole, isoxazole, sulphonamide moieties and aryl azo quinolone derivatives, which
were used as precursors to synthesize their corresponding phthalocyanine derivatives.
The reactions are experimentally very simple, and the reaction mechanisms were
discussed. The results obtained by preliminary screening of antioxidant activity and
cytotoxicity against different cell lines suggested that compounds 13 & 14 may serve as
interesting compounds for the development of new antioxidant and antitumor agents.
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Moser FH, Tomas AL. The Phthalocyanines, Vols. 1-2, CRC press, Boca Ration
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[7]
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