Direct one-pot cobalt(II) phthalocyanine catalyzed synthesis of N-substituted isoindolinones

Article abstract of DOI:10.1071/CH12321

A direct one-pot synthetic approach is described wherein cobalt(II) phthalocyanine (CoPc) catalyzed reductive amination of 2-carboxybenzaldehyde, followed by intramolecular amidation afforded N-substituted isoindolinones. The method used diphenylsilane as reducing agent in ethanol. High chemoselectivity with excellent yield was obtained in most of the studied substrates.

Full text of DOI:10.1071/CH12321

RESEARCH FRONT
CSIRO PUBLISHING
Aust. J. Chem. 2012, 65, 1594–1598
Full Paper
http://dx.doi.org/10.1071/CH12321
Direct One-Pot Cobalt(II) Phthalocyanine Catalyzed
Synthesis of N-Substituted Isoindolinones
A
A
A
Vishal Kumar, Upendra Sharma, Bikram Singh,
A B
,
and Neeraj Kumar
A
Natural Plant Products Division, CSIR-Institute of Himalayan Bioresource Technology,
Palampur, Himachal Pradesh-176 061, India.
B
Corresponding author. Email: neerajnpp@rediffmail.com
A direct one-pot synthetic approach is described wherein cobalt(II) phthalocyanine (CoPc) catalyzed reductive amination
of 2-carboxybenzaldehyde, followed by intramolecular amidation afforded N-substituted isoindolinones. The method
used diphenylsilane as reducing agent in ethanol. High chemoselectivity with excellent yield was obtained in most of the
studied substrates.
Manuscript received: 5 July 2012.
Manuscript accepted: 10 September 2012.
Published online: 24 October 2012.
Introduction
isoindolinone as the only product in the reaction of
2-carboxybenzaldehyde and aniline.[15] Inspired by this result
and the importance of these compounds, we explored the
CoPc/Ph2SiH2/EtOH system for the synthesis of different
N-substituted isoindolinone derivatives. More recently, Shi
et al. have reported on a Pt nanowires catalyzed method for
the synthesis of these compounds from 2-carboxybenzaldehyde
in dioxane (Fig. 2).[16] The use of a costly Pt metal catalyst,
which is at high risk of depletion, and a toxic solvent[17] were the
limitations. Also, Capello et al. have found that solvents like
dioxane and DMF are among the worst concerning health,
safety, environmental factors, energy requirements, and envi-
ronmental impact of the synthesis. In contrast, small alcohols
such as ethanol and methanol are among the green solvents.[18]
In this context, we report here on the first CoPc catalyzed
highly chemoselective synthesis of N-substituted isoindolinones
in ethanol as an inexpensive and safe solvent.
The isoindolinone skeleton is widespread among many drugs of
natural and synthetic origin.[1] N-substituted isoindolinones are
known to possess important biological activities such as anti-
inflammation, anticancer, and immunomodulation. (Fig. 1).[2]
Lenalidomide is a United States Food and Drug Administration
(FDA) approved drug for the treatment of multiple myeloma.[3]
It has also been approved for the treatment of hematological
disorders known as myelodysplastic syndromes in 2006.[3]
Another analogue, CC3052, is a potent inhibitor of TNF-a
production.[4] Indoprofen is a non-steroidal antiinflammatory
drug and has been found to increase production of the survival of
the motor neuron protein.[5] Recently, Uno et al. have described
these compounds as potent hypoxia-inducible factor-1a
inhibitors.[6]
Several synthetic strategies have been developed for the
synthesis of N-substituted isoindolinones such as condensation
of amines with phthalide or 2-(bromomethyl)benzoate,[7] mono-
reduction of phthalimide,[7,8] and Pd catalyzed cycloaminocar-
bonylation of 2-iodobenzylbromide, 2-iodobenzylamine,[9] and
2-bromobenzaldehyde (Fig. 2).[10] Cao et al. described Pd
catalyzed carbonylation-hydroamination reactions of 1-halo-2-
alkynylbenzene and amines for the synthesis of isoindolinone
derivatives in ionic liquid.[11] Rousseaux et al. described a Pd
catalyzed intramolecular alkylation of amides to obtain this
skeleton.[12] Marion et al. have developed a Pt catalyzed
approach involving cycloisomerization of o-halobenzyl- or
o-halobenzoylynamides.[13] However, methods involving
environmentally benign reaction conditions, a cheap catalytic
system, and easily available starting material avoiding the use of
highly toxic CO are always in demand.
OCH3
OCH3
O
NH
N
O
N
O
NH2
O
O
Lenalidomide
CC3052
COOH
N
In continuation of our work on metal phthalocyanines as
catalysts,[14] we have recently reported the cobalt(II) phthalocy-
anine (CoPc)/Ph2SiH2/EtOH catalyzed highly chemoselective
reductive amination of carbonyl compounds, and got N-phenyl
O
Indoprofen
Fig. 1. Examples of clinically used N-substituted isoindolinones.
Journal compilation Ó CSIRO 2012
www.publish.csiro.au/journals/ajc

N-Substituted Isoindolinones
1595
Previous art
CHO
Br
Br
OMe
R-NH2, K2CO3
toluene, H2O
reflux
O
[Ref. 10]
R-NH2
PdCl2(PhCN)2
[Ref. 7]
CO, DMF, 100ꢀC
O
O
R-NH2, 205–210ꢀC
R-NH2, Pt nanowires
H
O
N
R
[Ref. 7]
dioxane, 24h
[Ref. 16]
OH
O
O
AcOH, HCl, Sn, reflux
1,4-bichloro-2-butene,
DMF, NaH, 0ꢀC
R-NH2
[Ref. 9]
[Ref. 7]
Pd(OAc)2/PPh3
CO, Et3N, DMF
50ꢀC
O
NH
O
Br
I
Present work
O
NH2
CoPc, Ph2SiH2
EtOH, 8h
H
N
O
ꢁ
OH
O
Fig. 2. Comparison of previous art and present work for the synthesis of N-substituted isoindolinones.
Table 1. Optimization of reaction conditionsA
2-(phenylimino)benzoic acid (Table 1, entries 1–3). Using
cobalt salts such as CoSO4.6H2O and CoCl2ꢀ6H2O afforded the
desired product in traces (Table 1, entries 6 and 7).
O
O
NH2
catalyst,
reducing agent
H
Further, to check the substrate scope, a wide range of
aromatic amines (Fig. 3) was investigated and the results are
summarized in Table 2. The reaction with aniline (2a) afforded
the desired isoindolinone in excellent yield (Table 2, entry 1).
No significant effect of the electron-withdrawing or releasing
nature of the substituent was observed. Aromatic amines having
electron-donating substituents, such as 4-OCH3, 4-CH3, and 4-I
2b–2d, gave the desired products in excellent yields with high
chemo-selectivity (Table 2, entries 2–4). The effect of steric
hindrance was seen in the reaction of o-substituted anilines
2g–2h giving the desired product in comparatively lower yields
(Table 2, entries 7 and 8). The NO2 group is highly susceptible to
reduction;[16] however, in the present case, this group remained
unaffected and the desired product was obtained in good yield
(Table 2, entry 5). An aniline with a strong electron-
withdrawing substituent such as 4-COCH3 generally affords a
low yield of product in the reductive amination step.[14] In the
presence of the CoPc/Ph2SiH2 system, the reaction of
4-acetylaniline (2f) proceeded smoothly and the desired product
was obtained in an excellent yield of 93 % (Table 2, entry 6). The
reaction was also successful with a heteroaromatic amine,
6-aminobenzothiazole (2i) and the product was obtained in good
yield (Table 2, entry 9).
N
ꢁ
EtOH, 70ꢀC
OH
O
Entry
Catalyst
Reducing agent
Yield [%]B
1
–
–
ND
2
–
Ph2SiH2
–
ND
3
4C
CoPc
ND
CoPc
Ph2SiH2
Ph2SiH2
Ph2SiH2
Ph2SiH2
ND
92D
5
CoPc
6
CoSO4ꢀ6H2O
Traces
Traces
7
CoCl2ꢀ6H2O
AReaction conditions: 2-carboxybenzaldehyde (1 mmol), aniline (1 mmol),
catalyst (1 mol-%), reducing agent (1.5 equiv.) at 708C for 8 h.
BYield based on GC-MS analysis. ND, not detected.
CReaction carried out at room temperature for 12 h.
DIsolated yield.
Results and Discussion
Reaction between 2-carboxybenzaldehyde and aniline was used
as a model reaction to determine the effect of the catalyst and the
reducing agent. While no desired product was obtained at room
temperature using the CoPc/Ph2SiH2 system (Table 1, entry 4),
an excellent yield (92 %) of N-phenyl isoindolinone was
obtained at 708C (Table 1, entry 5). Also, in the absence
of catalyst or reducing agent, the desired product was not
detected and most of the substrate was converted to imine,
A wide range of aliphatic amines (Fig. 3) were also tried and
gave excellent yields of products (Table 3). In a Pd catalyzed
approach by Cho and Ren involving cycloaminocarbonylation
of 2-bromobenzaldehyde for the synthesis of the isoindolinone
skeleton,[10] a very low yield of the product was obtained for
aliphatic amines such as benzylamine. However, under our
present reaction conditions, good to excellent yields were

1596
V. Kumar et al.
NH2
NH2
NH2
NH2
NH2
NH2
NH2
H3CO
H3COC
NH2
O2N
NH2
I
2a
2b
2c
2d
2e
2f
2g
NH2
H2N
S
N
NH2
NH2
OCH3
H3CO
2h
2i
4a
4b
4c
4d
OH
Br
NH2
NH2
NH2
Br
NH2
NH2
H3CO
Br
Br
4e
4f
4g
4h
4i
Fig. 3. Amines employed in the reaction.
Table 3. CoPc catalyzed synthesis of N-substituted isoindolinones
using aliphatic aminesA
Table 2. CoPc catalyzed synthesis of N-substituted isoindolinones
using aromatic aminesA
O
O
NH2
CoPc, Ph2SiH2
CoPc, Ph2SiH2
H
H
N
N
R
ꢁ
R-NH2
ꢁ
EtOH, 70ꢀC
OH
R
EtOH, 70ꢀC
OH
R
O
O
O
1
O
2
3
1
4
5
Entry
Amine
Product
Time [h]
Yield [%]B
Entry
Amine
Product
Time [h]
Yield [%]B
1
2
3
4
5
6
7
8
9
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
3e
3f
6
5
5
7
8
8
7
8
8
92
1
2
3
4
5
6
7
8
9
4a
4b
4c
4d
4e
4f
5a
5b
5c
5d
5e
5f
8
8
8
8
8
8
8
8
8
91C
92
89
93
90
96
93
94
85
94
92
94
75C
93C
70C
58
2g
2h
2i
3g
3h
3i
4g
4h
4i
5g
5h
5i
71
AReaction conditions: 2-carboxybenzaldehyde (1 mmol), amine (1 mmol),
diphenylsilane (1.5 mmol), CoPc (1 mol-%) in EtOH (5 mL) at 708C.
BIsolated yield.
AReaction conditions: 2-carboxybenzaldehyde (1 mmol), amine (1 mmol),
diphenylsilane (1.5 mmol), CoPc (1 mol-%) in EtOH (5 mL) at 708C.
BIsolated yield.
CYield based on GC-MS analysis of reaction mixture.
CYield based on GC-MS analysis of reaction mixture.
obtained (Table 3, entries 1–9). 2-Acetylbenzoic acid was also
tested in the reaction with different amines, however, the
reaction stopped at the imine stage and the desired isoindolinone
was not observed (Scheme 1), which may be due to steric
hindrance of neighbouring groups preventing the attack of
hydride.
NH2
O
R
CoPc, Ph2SiH2
N
ꢁ
OH
OH
EtOH, 70ꢀC, 12h
R
O
O
6
2
7
R ꢂ H,
R ꢂ CH3,
7a
7c
84 %
90 %
Conclusions
Scheme 1.
A series of N-substituted isoindolinones has been synthesized
by reductive amination-intramolecular amidation of 2-
carboxybenzaldehyde in one pot using Ph2SiH2 as reducing
agent in ethanol. Use of a green solvent and easily available
starting material with low loading of catalyst under ambient
reaction conditions makes the present method superior to earlier
reported methods. Other remarkable advantages of this meth-
odology include high isolated yields, clean reactions, and an
easy work-up procedure.
Experimental
General
Cobalt phthalocyanine was synthesized by a reported proce-
dure[19] with some modification and characterized by infrared
spectroscopy and UV-VIS spectroscopy. Silica gel (60–120
mesh) was used for column chromatography and was purchased

N-Substituted Isoindolinones
1597
from Sisco Research Laboratories Pvt. Ltd India. Other che-
micals were purchased from Spectrochem (India), Merck
(Germany), and Sigma–Aldrich (USA) and were used without
further purification. NMR spectra were recorded on a Bruker
Avance-300 spectrometer. Mass spectra were recorded on a
QTOF-Micro instrument from Waters Micromass and Maxis-
Bruker. The GC-MS analysis was carried out on a Shimadzu (QP
2010) series Gas Chromatogram-Mass Spectrometer (Tokyo,
Japan), AOC-20i auto-sampler coupled, and a DB-5MS capil-
lary column, (30 m ꢁ 0.25 mm i.d., 0.25 mm). The initial tem-
perature of the column was 708C held for 4 min and was
programmed to 2308C at 48C minꢂ1, then held for 15 min at
2308C; the sample injection volume was 2 mL in GC grade
dichloromethane. Helium was used as carrier gas at a flow rate
of 1.1 mL minꢂ1 on split mode (1 : 50).
N-(2,6-Dimethylphenyl)isoindolinone 3h
Eluent –ethyl acetate : n-hexane (2 : 8), RF 0.45, brown oil.
dH (300 MHz, CDCl3) 7.99 (d, J 7.8, 1H), 7.61–7.63 (m, 1H),
7.52–7.56 (m, 2H), 7.16–7.21 (m, 3H), 4.62 (s, 2H), 2.20 (s, 6H);
dC (75 MHz, CDCl3) 168.3, 142.1, 137.2, 134.8, 132.7, 132.1,
128.98, 128.91, 128.6, 124.7, 123.3, 51.6, 18.3.
N-Phenethylisoindolinone 5b
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.50, brown solid,
mp 88–908C. dH (300 MHz, CDCl3) 7.86 (d, J 7.2, 1H), 7.43–
7.54 (m, 2H), 7.39 (d, J 7.2, 1H), 7.21–7.33 (m, 5H), 4.22 (s, 2H),
3.89 (t, J 7.3, 2H), 3.01 (t, J 7.3, 2H); dC (75 MHz, CDCl3) 168.8,
141.5, 139.2, 133.2, 131.5, 129.1, 129.0, 128.3, 126.9, 124.0,
123.0, 51.0, 44.5, 35.3; HRESIMS calcd for C16H15NNaO
[MþNa]þ 260.1051, found 260.1042.
General Procedure for the Synthesis of N-Substituted
Isoindolinones
N-(20-Methoxyphenethyl)isoindolinone 5c
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.55, brown oil.
dH (300 MHz, CDCl3) 7.85 (d, J 7.3, 1H), 7.42–7.51 (m, 2H),
7.38 (d, J 7.3, 1H), 7.14–7.24 (m, 2H), 6.83–6.89 (m, 2H), 4.25
(s, 2H), 3.84–3.89 (m, 2H), 3.81 (s, 3H), 2.99–3.04 (m, 2H); dC
(75 MHz, CDCl3) 168.8, 158.0, 141.7, 133.4, 131.4, 130.9,
128.2, 127.5, 123.9, 122.9, 121.0, 110.6, 55.6, 50.9, 42.9,
30.0; HRESIMS calcd for C17H17NNaO2 [MþNa]þ 290.1157,
found 290.1156.
To a stirred suspension of CoPc (0.01 mmol) in ethanol were
added 2-carboxybenzaldehyde (1.0 mmol), amine (1.0 mmol),
and diphenylsilane (1.5 mmol) at room temperature. The tem-
perature was then raised to 708C. After, completion of the
reaction (as monitored by TLC), the reaction mixture was fil-
tered and passed through anhydrous Na2SO4. The crude
product was purified by column chromatography over silica-gel
(60–120) mesh.
N-(40-Methoxyphenethyl)isoindolinone 5d
Characterization Data of Products
Eluent – ethyl acetate : n-hexane (3 : 7), RF 0.60, yellow solid,
mp 95–978C. dH (300 MHz, CDCl3) 7.85 (d, J 7.3, 1H), 7.42–
7.53 (m, 2H), 7.38 (d, J 7.3, 1H), 7.16 (d J 8.3, 2H), 6.83 (d, J 8.3,
2H), 4.20 (s, 2H), 3.81–3.86 (m, 2H), 3.78 (s, 3H), 2.92–2.97 (m,
2H); dC (75 MHz, CDCl3) 168.8, 158.6, 141.5, 133.2, 131.5,
131.2, 130.0, 128.3, 123.9, 123.0, 114.4, 55.6, 51.0, 44.6, 34.3;
HRESIMS calcd for C17H17NNaO2 [MþNa]þ 290.1157, found
290.1162.
N-Phenylisoindolone 3a
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.47, white solid,
mp 133–1358C. dH (300 MHz, CDCl3) 7.88–7.96 (m, 2H), 7.78
(m, 1H), 7.59–7.61 (m, 1H), 7.52–7.55 (m, 1H), 7.42–7.50 (m,
3H), 7.17–7.22 (m, 1H), 4.76–4.88 (m, 2H); dC (75 MHz,
CDCl3) 168.0, 140.5, 139.9, 133.6, 132.4, 129.5, 128.7, 124.8,
124.5, 123.0, 119.8, 51.1; HRESIMS calcd for C14H11NNaO
[MþNa]þ 232.0738, found 232.0739.
N-(20-Bromophenethyl)isoindolinone 5e
N-(4-Methoxyphenyl)isoindolinone 3b
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.55, yellow solid,
mp 86–888C. dH (300 MHz, CDCl3) 7.84 (d, J 7.4, 1H), 7.51–
7.55 (m, 2H), 7.45 (d, J 7.4, 1H), 7.37–7.40 (m, 1H), 7.27–7.31
(m, 1H), 7.17–7.22 (m, 1H), 7.06–7.11 (m, 1H), 4.26 (s, 2H),
3.84–3.89 (m, 2H), 3.10–3.15 (m, 2H); dC (75 MHz, CDCl3)
168.9, 141.6, 138.4, 133.3, 133.1, 131.6, 131.3, 128.8, 128.3,
128.1, 124.8, 124.0, 123.0, 50.9, 42.7, 35.4; HRESIMS calcd for
C16H14BrNNaO [MþNa]þ 338.0156, found 338.0141.
Eluent – ethyl acetate : n-hexane (3 : 7), RF 0.50, yellow solid,
mp 193–1958C. dH (300 MHz, CDCl3) 7.92 (d, J 7.9, 1H), 7.75
(d, J 8.8, 2H), 7.48–7.60 (m, 3H), 6.97 (d, J 8.8, 2H), 4.79
(s, 2H), 3.82 (s, 3H); dC (75 MHz, CDCl3) 167.6, 157.0, 140.5,
133.6, 132.2, 128.8, 128.0, 124.3, 122.9, 121.8, 114.7, 55.8,
51.5.
N-(4-Methylphenyl)isoindolinone 3c
N-(30-Bromophenethyl)isoindolinone 5f
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.54, brown solid,
mp 134–1358C. dH (300 MHz, CDCl3) 7.93 (d, J 7.6, 1H), 7.75
(d, J 8.0, 2H), 7.57–7.62 (m, 1H), 7.50–7.52 (m, 2H), 7.24 (d, J
8.0, 2H), 4.82 (s, 2H), 2.36 (s, 3H); dC (75 MHz, CDCl3) 167.7,
140.5, 137.3, 134.5, 133.7, 132.3, 130.0, 128.7, 124.4, 122.9,
119.9, 51.2, 21.2.
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.50, light brown
solid, mp 118–1208C. dH (300 MHz, [D4]methanol) 7.68 (d, J
7.4, 1H), 7.49–7.51 (m, 1H), 7.39–7.45 (m, 3H), 7.27–7.29 (m,
1H), 7.13–7.20 (m, 2H), 4.32 (s, 2H), 3.75–3.80 (m, 2H), 2.89–
2.96 (m, 2H); dC (75 MHz, [D4]methanol) 170.2, 142.8, 142.3,
132.8, 132.4, 130.9, 130.2, 128.7, 128.2, 123.7, 123.6, 123.1,
51.3, 44.4, 34.6.
N-(4-Iodophenyl)isoindolinone 3d
N-(40-Bromophenethyl)isoindolinone 5g
Eluent – ethyl acetate : n-hexane (1 : 9), RF 0.43, yellow solid,
mp 140–1428C. dH (300 MHz, CDCl3) 7.90 (d, J 7.5, 1H), 7.64–
7.72 (m, 4H), 7.59–7.61 (m, 1H), 7.50–7.52 (m, 2H), 4.80 (s,
2H); dC (75 MHz, CDCl3) 167.9, 140.2, 139.6, 138.4, 133.2,
132.7, 128.9, 124.5, 123.0, 121.3, 88.2, 50.8.
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.55, off white
solid, mp 120–1228C. dH (300 MHz, [D4]methanol) 7.75 (d, J
7.5, 1H), 7.46–7.59 (m, 3H), 7.41–7.43 (m, 2H), 7.17–7.20 (m,
2H), 4.40 (s, 2H), 3.84–3.89 (m, 2H), 2.96–3.01 (m, 2H); dC

1598
V. Kumar et al.
(75 MHz, [D4]methanol) 169.6, 142.2, 138.4, 132.3, 131.8,
131.6, 130.7, 128.1, 123.1, 123.0, 120.2, 50.7, 43.8, 33.8.
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N-(30-Bromo-40-methoxyphenethyl)isoindolinone 5h
Eluent – ethyl acetate : n-hexane (3 : 7), RF 0.45, yellow solid,
mp 114–1168C. dH (300 MHz, CDCl3) 7.84 (d, J 7.4, 1H), 7.43–
7.52 (m, 3H), 7.40 (d, J 7.4, 1H), 7.12–7.16 (m, 1H), 6.80–6.83
(m, 1H), 4.24 (s, 2H), 3.86 (s, 3H), 3.80–3.82 (m, 2H), 2.89–2.94
(m, 2H); dC (75 MHz, CDCl3) 168.9, 154.9, 141.4, 133.8, 133.1,
132.7, 131.6, 129.0, 128.4, 124.0, 123.0, 112.4, 112.0, 56.6,
50.9, 44.4, 34.0.
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N-(1-Hydroxyphenethyl)isoindolinone 5i
Eluent – ethyl acetate : n-hexane (4 : 6), RF 0.60, brown solid,
mp 153–1558C. dH (300 MHz, [D6]DMSO) 7.67 (d, J 7.4, 1H),
7.55–7.61 (m, 2H), 7.44–7.51 (m, 1H), 7.25–7.40 (m, 5H), 5.61–
5.63 (m, 1H), 4.84–4.90 (m, 1H), 4.57–4.63 (m, 1H), 4.33–4.39
(m, 1H), 3.66–3.68 (m, 2H); dC (75 MHz, [D6]DMSO) 167.7,
143.5, 142.3, 132.5, 131.4, 128.3, 127.9, 127.4, 126.2, 123.4,
122.8, 71.4, 51.2, 50.1.
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2-(10-Methyl-N-phenylimino)benzoic acid 7a
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.45, off white
solid, dH (300 MHz, CDCl3) 7.89–7.92 (m, 1H), 7.66–7.71 (m,
1H), 7.55–7.59 (m, 2H), 7.02–7.08 (m, 2H), 6.82–6.87 (m, 1H),
6.54–6.57 (m, 2H), 1.96 (s, 3H); dC (75 MHz, CDCl3) 169.1,
150.6, 142.4, 134.8, 130.5, 129.3, 128.0, 126.1, 122.7, 122.2,
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2-(10-Methyl-N-tolylimino)benzoic acid 7c
Eluent – ethyl acetate : n-hexane (2 : 8), RF 0.50, off white
solid, dH (300 MHz, CDCl3) 7.86–7.88 (m, 1H), 7.66–7.69 (m,
1H), 7.55–7.59 (m, 2H), 6.87 (d, J 8.2, 2H), 6.53 (d, J 8.2, 2H),
2.19 (s, 3H), 1.95 (s, 3H); dC (75 MHz, CDCl3) 169.2, 150.5,
139.5, 134.6, 132.5, 130.4, 129.8, 128.1, 126.0, 122.8, 121.5,
98.6, 28.6, 20.9.
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Supplementary Material
General experimental, procedure for synthesis of cobalt
phthalocyanines, general procedure for the synthesis of
N-substituted isoindolinones, and H and 13C NMR spectra of
synthesized compounds are available on the Journal’s website.
1
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Acknowledgements
Authors are grateful to Dr P. S. Ahuja, Director, IHBT, Palampur for
encouragement and support. VK and US are thankful to UGC and CSIR for
granting senior research fellowships.
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