Synthesis and characterization of novel monoazo N-ester-1,8-naphthalimide disperse dyestuffs

Article abstract of DOI:10.1002/jccs.200700147

Five novel monoazo disperse dyestuffs based on N-ester-1,8-naphthalimide were synthesized. Acenaphthene was nitrated, then oxidized to 4-nitro-1,8-naphthalic anhydride. 4-Nitro-1,8-naphthalic anhydride was reacted with methyl and ethyl glycinate in alcoholic media, followed with reduction. 4-Amino-N-methyl and ethyl glycinate-1,8-naphthalimide were obtained. These products were diazotized and coupled with appropriate aromatic amines to give bluish-red or violet dyestuffs. All intermediates and dyestuffs were purified and characterized by ¹H-NMR, FTIR, DSC, UV-VIS and Elemental Analysis. Dispersion of dyestuffs was prepared in water and applied to polyester fabrics. The dyed fabrics showed that four of the synthesized dyestuffs were suitable for coloring polyester fibers, producing deep bluish red with very good build up properties.

Full text of DOI:10.1002/jccs.200700147

Journal of the Chinese Chemical Society, 2007, 54, 1021-1028
1021
Synthesis and Characterization of Novel Monoazo
N-ester-1,8-naphthalimide Disperse Dyestuffs
Kamaladin Gharanjig,a,b Mokhtar Arami,a* Shohre Rouhani,b Hajir Bahrami,a
Barahman Movassaghc and Niyaz Mohammad Mahmoodib
aAmirkabir University of Technology, Faculty of Textile Engineering, P.O. Box 15875-4413, Tehran-Iran
bIran Color Research Center, Department of Colorant Manufacture and Environmental Protection,
P.O. Box 1665618481, Tehran-Iran
cK. N. Toosi University of Technology, Department of Chemistry, P.O. Box 15875-4413, Tehran-Iran
Five novel monoazo disperse dyestuffs based on N-ester-1,8-naphthalimide were synthesized.
Acenaphthene was nitrated, then oxidized to 4-nitro-1,8-naphthalic anhydride. 4-Nitro-1,8-naphthalic an-
hydride was reacted with methyl and ethyl glycinate in alcoholic media, followed with reduction.
4-Amino-N-methyl and ethyl glycinate-1,8-naphthalimide were obtained. These products were diazo-
tized and coupled with appropriate aromatic amines to give bluish-red or violet dyestuffs.
All intermediates and dyestuffs were purified and characterized by 1H-NMR, FTIR, DSC, UV-VIS
and Elemental Analysis. Dispersion of dyestuffs was prepared in water and applied to polyester fabrics.
The dyed fabrics showed that four of the synthesized dyestuffs were suitable for coloring polyester fibers,
producing deep bluish red with very good build up properties.
Keywords: Disperse dyestuffs; 4-Amino-N-alkylglycinate-1,8-naphthalimide; Azo dyestuffs;
Dyeing; Diazotization; Coupling.
INTRODUCTION
Consumption of disperse azo dyestuffs is more than
methylglycinate-naphthalimide and 4-amino-N-ethyl gly-
cinate-1,8-naphthalimide as diazo components and N,N-
diethylaniline and N,N-diethyl-m-toluidine, as the cou-
pling components. In this respect, acenaphthene was ni-
trated and further treated using different unit processes
such as oxidation, imidation, reduction, diazotisation and
finally coupled with selected amines (Fig. 1). The interme-
diates and dyestuffs were purified and characterized by an-
alytical methods (1H-NMR, FTIR, DSC, UV-VIS and Ele-
mental Analysis). The spectrophotometric properties of the
synthesized dyestuffs in various solvents were examined.
These dyestuffs were applied to polyester fibers and dyeing
properties were investigated.
50% of the total amount of the production of disperse dye-
stuffs in the world.1 Relatively simple synthesis method for
these dyestuffs enables the production of a wide range of
colours of high tensity and brightness from greenish yellow
to cyan with this chromophore system.2
4-Amino-N-substituted-1,8-naphthalimides are use-
ful intermediates for the synthesis of monoazo disperse
dyestuffs. These dyestuffs have been considered for dyeing
of polyester fibers.3-5
Diazotization of 4-amino-N-alkyl-1,8-naphthalimides
and coupling to aryl amines or naphthols gives red to bluish
red disperse dyestuffs while, similar coupling to p-amino-
acetophenone produces yellow disperse dyestuffs.4,6
The synthesized dyestuffs have very good affinity to-
wards polyester fibers with good color fastness properties
and also they possess excellent sublimation fastness.3,5
In the present study, a series of novel monoazo dis-
perse dyestuffs have been synthesized using 4-amino-N-
EXPERIMENTAL
Materials and Apparatus
Acenaphthene, N,N-diethylaniline, N,N-diethyl-m-
toluidine, methyl glycinate, ethyl glycinate and 3-(N,N-di-
ethylamino)acetanilide were purchased from Aldrich Co.
* Corresponding author. Tel: +98-21-64542614; Fax: +98-21-66400245; E-mail: arami@aut.ac.ir

1022 J. Chin. Chem. Soc., Vol. 54, No. 4, 2007
Gharanjig et al.
CH2COOR
O
O
O
N
O
O
HNO3
H2NCH2COOR
NaCr2O7
H2SO4
CH3COOH
NO2
NO2
1,2
NO2
CH2COOR
CH2COOR
CH2COOR
O
N
O
O
N
O
O
N
O
SnCl2
HCl
NaNO2
H2SO4
Coupling
-
X
+
N=N HSO4
CH2CH3
CH2CH3
NH2
3,4
N=N
N
5,6,7,8,9
1,3) R=CH3 2,4) R=C2H5 5) R=CH3 X=H 6) R=CH3 X=CH3 7) R=C2H5 X=H 8) R=C2H5 X=CH3 9) R=C2H5 X=NHCOCH3
Fig. 1. Synthesis of dyestuffs from acenaphthene.
and used without further purification. Melting points were
determined by DSC using a Differential Scanning Calorim-
eter 2010 TA Instrument. The 1H-NMR spectra were ob-
tained with a Bruker AVANCE-300 MHZ using the appro-
priate deuterated solvent. FTIR absorption spectra were
recorded on a Nicolet 470/670/870. UV-VIS absorption
spectra were measured in a Cecil 9200 double beam spec-
trophotometer. The colorimetric properties of the dyeings
(D65 illumination, 10° observer) were obtained using a
Gretag-Macbeth 7000A spectrophotometer.
Synthesis of 4-nitro-N-methylglycinate-1,8-naphtha-
limide
5.94 g (0.03 mol) of 4-nitro-1,8-naphthalic anhydride
was dissolved in 200 mL absolute ethanol with stirring and
heating. 3.56 g (0.04 mol) methyl glycinate was added and
the mixture was refluxed until TLC showed no 4-nitro-
1,8-naphthalic anhydride left; this reaction was completed
in 16 hours. The mixture was solidified in water, filtered off
and recrystallized.
Synthesis of 4-amino-N-ethylglycinate-1,8-naphtha-
limide
Synthesis of Intermediates
A mixture of 6 g (18 mmol) 4-nitro-N-ethylglycinate-
1,8-naphthalimide and 20.31 g (90 mmol) stannous chlo-
ride in 90 mL ethanol was refluxed for 1 hour with 22.5 mL
hydrochloric acid till the reaction completed. The mixture
was poured into 300 mL water and the precipitated solid
was filtered off. The crude product was purified by column
chromatography (eluent: acetone/toluene = 2/1).
Synthesis of 4-amino-N-methylglycinate-1,8-naphtha-
limide
Synthesis of 5-nitroacenaphthene and 4-nitronaphthalic
anhydride
5-Nitroacenaphthene and 4-nitronaphthalic anhy-
dride were synthesized following the method of Okazaki
and Taniguchi.7
Synthesis of 4-nitro-N-ethylglycinate-1,8-naphthalimide
3.96 g (0.02 mol) of 4-nitro-1,8-naphthalic anhydride
was dissolved in 100 mL absolute ethanol with stirring and
heating. 3.09 g (0.03 mol) ethyl glycinate was added and
the mixture was refluxed until TLC showed no 4-nitro-
1,8-naphthalic anhydride remained. This reaction was
completed in 10 hours. The mixture was then poured into
water. The precipitated solid was filtered off and recrys-
tallised.
A solution of 6 g (19 mmol) 4-nitro-N-methylgly-
cinate-1,8-naphthalimide and 21 g (93 mmol) stannous
chloride in 150 mL ethanol was refluxed 60 minutes with
30 mL hydrochloric acid and then the mixture was solidi-
fied in 300 mL water and filtered off. The crude product
was purified by column chromatography (eluent : ace-

Novel Monoazo Naphthalimide Dyestuffs
tone/toluene = 2/1).
J. Chin. Chem. Soc., Vol. 54, No. 4, 2007 1023
detergent (5 g/l) at 80 °C for 20 min. prior to being used for
the dyeing. Dyeing was carried out in a Rotadyer apparatus
(Nasaj Sanat Yazd, Ltd) using a liquor ratio of 50:1, pH =
4-5 (Acetic acid). The amounts of the dyestuff dispersion
were 0.1, 0.3, 0.5, 0.7, 1, 1.5, 2 and 4% (owf). Dyeing was
performed by raising the dye bath temperature from 30 °C
to 90 °C at 2 °C/min, followed by 90 °C to 130 °C at 1
°C/min, holding at this temperature for 60 min and cooling
to 70 °C at 3 °C/min. The dyed fabrics were reduction
cleared with 2 g/l sodium hydrosulphite, 1 g/l sodium hy-
droxide, 1 g/l detergent for 20 min at 50 °C, then thor-
oughly rinsed by cold water.
Synthesis of Dyestuffs
Diazotisation of 4-amino-N-ethylglycinate-1,8-naphtha-
limide
0.37 g (5.3 mmol) of sodium nitrite was added slowly
to 2.32 mL of concentrated sulphuric acid (98%) at below
10 °C. The temperature of the reaction rose to 65 °C, where
no color change occurred. The solution was then cooled to
5 °C and 1.58 g (5.3 mmol) of the powder of 4-amino-N-
ethylglycinate-1,8-naphthalimide was added slowly to the
solution over 40 min. The reaction mixture was stirred for 3
hours.
Diazotization of 4-amino-N-methylglycinate-1,8-naph-
thalimide
RESULTS AND DISCUSSION
0.37 g (5.3 mmol) of sodium nitrite was added slowly
to 2.2 mL of concentrated sulphuric acid at a temperature
less than 10 °C where no color change occurred. 1.505 g
(5.3 mmol) of the powder of 4-amino-N-methylglycinate-
1,8-naphthalimide was added slowly to the obtained solu-
tion over 40 min. The reaction mixture was stirred for 3
hours.
Synthesis of Intermediates and Dyestuffs
The most convenient starting material for the prepa-
ration of naphthalimide dyestuffs is acenaphthene, which is
reasonably cheap and easily available as a by-product of
processes in the coal industry. In this work acenaphthene
was utilized for preparing a number of novel naphthalimide
disperse dyestuffs. Acenaphthene was reacted with nitric
acid in an acetic acid media at room temperature giving yel-
low needle crystals having an m.p of 101-102 °C. The yield
of the reaction was 85.9%. Naphthalic anhydride or substi-
tuted naphthalic anhydrides reacts with amines such as am-
monia or alkyl amines to form the corresponding naphtha-
limides. Therefore, 4-nitro-1,8-naphthalic anhydride was
reacted with methyl or ethyl glycinate. The reaction was
carried out in absolute ethanol media under reflux condi-
tion, and the end point of the reaction was examined by
TLC on silica gel 60. TLC showed the imidation of 4-ni-
tro-1,8-naphthalic anhydride with ethyl and methyl gly-
cinate completed at 10 and 16 hours, respectively. The time
required for completion of the imidation reaction for 4-ni-
tro-1,8-naphthalic anhydride with methyl or ethyl glycinate
is more than for the imidation of 4-nitro-1,8-naphthalic an-
hydride with alkyl amines.8,9 This can be attributed to the
alkyl amines being more active than the alkyl glycinates in
the nucleophilic displacement reaction in which the attack-
ing group is amine.
Coupling
The N,N-diethylaniline, N,N-diethyl-m-toluidine and
3-(N,N-diethylamino)acetanilide used as coupling compo-
nents were:
Separately, 5.3 mmol of each coupling components
was dissolved in 1 mL acetic acid. Then the clear diazonium
salt solution was added to these solutions. The reaction
mixture was stirred for 1 hour at below 10 °C. Then the pH
of the solution was maintained between 4 and 5 by adding
dropwise sodium acetate solution. Stirring was continued
for 3 hours at less than 10 °C. The dyestuffs were filtered
off, washed with hot water and dried. The crude products
were purified with preparative TLC on silica gel (solvent:
chloroform).
Preparation of dye dispersions
0.5 g of the crude dye, 1 g of the dispersing agent
(Lyoprint EV, Ciba Co.) and 2 mL water were added to a
mortar and milled for 60 min. Then, 20 mL water was
added to this mixture. The mixture was transferred to a ball
mill and treated for 20 hours. The mixture was diluted with
an addition of water to 100 mL and then filtered by Micro-
Prazisions Sieb Fritsch (5 mm).
The yields (Y%), melting points, the form and color
of crystals of intermediate products: 4-nitro-N-alkylgly-
cinate-1,8-naphthalimides are given in Table 1. The FTIR,
1H-MNR spectra and Elemental Analysis data of 4-nitro-
N-alkyl-glycinate-1,8-naphthalimides are given in Table 2.
Dyeing
Polyester fabric (1 g) was pretreated with a nonionic

1024 J. Chin. Chem. Soc., Vol. 54, No. 4, 2007
Gharanjig et al.
Table 1. Characteristics of synthesized intermediates
Reaction conditions
Reaction Solvent time (hrs.) mp (°C)
Product
Series No.
Y (%)
Form
Color
1
2
3
4
Imidation Ethanol
Imidation Ethanol
Reduction Ethanol
Reduction Ethanol
16
10
1
196.22
169.75
228.05
227.55
82.75
92.28
77.82
84.97
needle
needle
needle
needle
fawn
fawn
orange
orange
1
Table 2. FTIR,1H NMR and elemental analysis of intermediates
Intermediates
1
FTIR, 1H NMR and elemental analysis
1H NMR (CDCl3): d 3.82 (3H, s, CH3), 4.96-4.98 (2H, s, NCH2), 8.00-8.05 (1H, J = 7.4
Hz, 6-H), 8.42-8.45 (1H, d, J = 8.0 Hz, 3-H), 8.72-8.79 (2H, 2-H, 5-H), 8.87-8.89 (1H, J
= 8.7 Hz, 7-H);
FTIR (KBr): n 3075.17 cm-1 (C-H str. Ar.), 2956.57 cm-1 (C-H str. Aliphatic), 1749.19
cm-1 (C=O str. ester), 1708.45, 1670.99 (C=O str. Carbonyl), 1583.33 (C=C str. Ar.),
1532.88, 1379.24 (NO2 str.);
Anal. Calcd for C15H10N2O6: C, 57.32%; H, 3.18%; N, 8.92%; Found: C, 57.4%; H,
3.3%; N, 9.1%.
2
1H NMR (CDCl3): d 1.30-1.35 (3H, t, J = 7.1 Hz, CH3), 4.24-4.31 (2H, q, J = 7.1 Hz,
CH2CH3), 4.954 (2H, s, NCH2), 7.98-8.03 (1H, J = 7.4 Hz, 6-H), 8.40-8.43 (1H,d, J =
8.0 Hz, 3-H), 8.70-8.77 (2H, 2-H, 5-H), 8.84-8.87 (1H, d, J = 8.7 Hz,7-H);
FTIR (KBr): n 3118.31 cm-1 (C-H str. Ar.), 2987.36 cm-1 (C-H str. Aliphatic), 1742.85
cm-1 (C=O str. ester), 1709.30 cm-1 (C=O str. Carbonyl), 1673.47 cm-1 (C=O str.
Carbonyl), 1595.44 cm-1 (C=C str. Ar.), 1523.20 cm-1 (NO2 str.), 1382.28 cm-1 (NO2
str.);
Anal. Calcd for C16H12N2O6: C, 68.78%; H, 4.19%; N, 9.27%; Found: C, 68.9%; H,
4.3%; N, 9.5%.
3
1H NMR (CD3COCD3): d 3.987 (3H, s, CH3), 4.84 (2H, s, N-CH2), 6.89 (2H, s, NH2),
6.93-7.01 (1H, d, J = 8.4 Hz, 3-H), 7.68-7.73 (1H, J = 7.8 Hz, 6-H), 8.29-8.32 (1H, d, J
= 8.4 Hz, 2-H), 8.51-8.52 (1H, d, J = 7.3 Hz, 5-H), 8.61-8.64 (1H, d, J = 8.3 Hz, 7-H);
FTIR (KBr): n 3364.98, 3258.08 cm-1 (N-H str. Primary amine), 2927.51 cm-1 (C-H str.
Aliphatic), 1734.82 cm-1 (C=O str. ester), 1685.45, 1642.62 (C=O str. carbonyl),
1577.96 (C=C str. Ar.);
Anal. Calcd for C15H12N2O4: C, 63.38%; H, 4.23%; N, 9.86%; Found: C, 63.5%; H,
4.4%; N, 9.6%.
4
1H NMR (CD3COCD3): d 1.24-1.29 (3H, t, J = 7.1 Hz, CH3), 4.16-4.23 (2H, q, J = 7.1
Hz, CH2CH3), 4.84 (2H, s, NCH2), 6.89 (2H, s, NH2), 6.99-7.02 (1H, d, J = 8.3 Hz, 3-
H), 7.68-7.73 (1H, J = 7.7 Hz, 6-H), 8.29-8.32 (1H, d, J = 8.4 Hz, 2-H), 8.51-8.54 (1H,
d, J = 7.3 Hz, 5-H), 8.61-8.64 (1H, d, J = 7.4 Hz,7-H);
FTIR (KBr): n 3367.89, 3256.39 cm-1 (N-H str. Primary amine), 2924.08 cm-1 (C-H str.
Aliphatic), 1730.04 cm-1 (C=O str. ester), 1686.12 cm-1, 1643.14 cm-1 (C=O str.
carbonyl), 1577.56 cm-1 (C=C Ar.);
Anal. Calcd for C16H14N2O4: C, 64.43%; H, 4.7%; N, 9.39%; Found: C, 65%; H, 4.9%;
N, 9.3%.
4-Amino-1,8-naphthalimides have been prepared by
reduction of the 4-nitro group of the appropriate naphthalic
anhydride or imide. Therefore, 4-amino-N-alkylglycinate-
1,8-naphthalimides were synthesized by the reaction of
4-nitro-N-alkylglycinate-1,8-naphthalimide with stannous
chloride(II) in hydrochloric acid as reducing agent and eth-
anol as solvent. Purification of product was carried out by
column chromatography on silica gel G (60-120) using ac-
etone and toluene (2/1) mixtures as eluent. The yields (Y%)
of obtained products: 4-amino-N-alkylglycinate-1,8-naph-
thalimides, their melting points and the form and color of
crystals are given in Table 1. The FTIR, 1H-NMR spectra

Novel Monoazo Naphthalimide Dyestuffs
J. Chin. Chem. Soc., Vol. 54, No. 4, 2007 1025
and elemental analysis of 4-amino-N-alkylglycinate-1,8-
naphthalimides are given in Table 2.
chromism shifts between toluene and DMF of the acetyl-
amino derivatives related to toluidine-based dyestuffs are
smaller.12 Comparing lmax of dyestuffs showed that for
dyestuffs lacking acetylamino substituents (dyestuffs 5-8)
the solvatochromism shifts are ~24-32 nm, while for dye-
stuff containing an acetylamino group (dyestuff 9), it is less
than 19 nm. This difference can be attributed to the weaker
solvatochromism of the acetylamino derivatives, despite
the fact that the acetylamino group of these dyestuffs causes
the dyestuff to be bright and bathochromic as a result of
intramolecular hydrogen bonding.12
The general method of diazotisation of 4-amino-1,8-
naphthalimide derivatives uses nitrosyl sulphuric acid.10,11
Thus 4-amino-N-alkylglycinate-1,8-naphthalimide was re-
acted with nitrosyl sulfuric acid. This reaction was com-
pleted in 3 hours. The obtained diazonium salts were re-
acted with various coupling components such as N,N-di-
ethylaniline, N,N-diethyl-m-toluidine and 3-(N,N-diethyl-
amino)acetanilide in weak acid media (pH = 4-5) (Fig. 1).
All analytical data of the synthesized dyestuffs (the yields
(Y%), DSC, FTIR, 1H-MNR spectra and Elemental Analy-
sis) are shown in Table 3.
The measurement of lmax in toluene and DMF showed
that lmax of the intramolecular charge transfer bands exhibit
a marked red shift on transfer from nonpolar to polar sol-
vents. This behavior indicates that the polar excited states
of the synthesized dyestuffs are stabilized by polarization
interaction forces as the polarizibility of the solvent is in-
creased.15
Electronic Absorption Spectra
It is a well-accepted fact that the constitution of dye-
stuffs have a fundamental role in producing desired color
over substrate. The correlation between the colour and con-
stitution is a highly interesting aspect of dyestuff develop-
ment and commercialization. Due to the abovementioned
points, the subject has attracted the attention of the compa-
nies producing commercial azo disperse dyestuffs.12,13 The
wavelength of maximum absorption (lmax) and the molar
absorption coefficients (emax) are all equally important for
dyestuffs.14 The absorption spectra of the dyestuffs 5-9
were determined in toluene, chloroform and DMF solvents,
respectively, and are summarized in Table 4. Comparing
the lmax of dyestuffs in chloroform for 5 and 6 with 7 and 8
shows that the nature of imide residue CH2COOR (R=CH3,
C2H5) is not very significant in the context of color change.
This finding is in good agreement with work of other re-
search groups.4 It is well known that the color of dyestuffs
is influenced by the introduction of additional donor groups
into the coupling component. One can easily deduce from
Table 4 that the presence of a methyl group in the 3-position
of N,N-diethyl-m-toluidine related to N,N-diethylaniline
was caused by the bathochromic effect (~ 8-10 nm) in dye-
stuffs 6 and 8.
Dyeing and Fastness Properties
The dyestuffs 5-9 were applied to polyester fabric un-
der high temperature dyeing conditions at concentrations
of 0.1, 0.3, 0.5, 0.7, 1, 1.5, 2 and 4 percent of dyestuffs
based on the weight of fabric. 0.5% Acetic acid (pH =
4.5-5) was added and the dyeing was carried out according
to Fig. 2. Dyed fabric was reduction cleared in an aqueous
solution containing 2 g/l of sodium hydrosulphite, 1 g/l of
sodium hydroxide and 1 g/l detergent for 20 min at 50 °C.
The treated polyester was then rinsed with hot and cold wa-
ter.
For elaborating on the buildup of the synthesized dye-
stuffs, the K/S was calculated by using the Kubelka-Mank
Equation (Eq. 1):
K/S = (1 - R)2/2R;
(1)
where K, S and R are absorption coefficient, scatter coeffi-
The introduction of a –NHCOCH3 group into the cou-
pling component of the dye 7 caused bathochromic shifts,
which is seen in dye 9 (~ 26 nm). The bathochromic shift of
the –NHCOCH3 group is particularly large. This batho-
chromic shift has been reported for other azo heterocyclic
compounds.12
The measurement of absorption at lmax in toluene and
DMF showed that the lowest Dlmax belongs to the dye 9.
Absorption maxima in Table 4 revealed that the solvato-
Fig. 2. Conditions of dyeing, L:R, liquor to goods ra-
tio, the volume of liquor employed on the
weight of fabric.

1026 J. Chin. Chem. Soc., Vol. 54, No. 4, 2007
Gharanjig et al.
Table 3. FTIR, 1H-NMR and elemental analysis of dyestuffs
Dyestuffs
5
FTIR, 1H NMR and elemental analysis
1H NMR (CDCl3): 1.276-1.346 (6H, CH2CH3), 3.50-3.57 (4H, q, J = 7.1 Hz,
CH2CH3), 3.81 (3H, s, COOCH3), 4.98-4.999 (2H, s, NCH2), 6.786-6.82 (2H, 3¢-H,
5¢-H), 7.83-7.88 (1H, J = 8.2 Hz, 6-H), 7.97-8.06 (3H, 2²-H, 6¢-H, 5-H), 8.66-8.699
(2H, 2-H, 7-H), 9.28-9.30 (1H, d, J = 8.7 Hz,3-H);
FTIR (KBr): n 2948.17 (C-H str. Ar.), 2929.34 cm-1 (C-H str. Aliphatic), 1738.74
cm-1 (C=O str. ester), 1688.95 cm-1, 1652.05 cm-1 (C=O str. Carbonyl), 1585.44 cm-1
(N=N str.);
Anal. Calcd for C25H24N4O4: C, 67.57%; H, 5.4%; N, 12.6%; Found: C, 67.2%; H,
5.1%; N, 12.8%.
6
1H NMR (CDCl3): 1.275-1.347 (6H,CH3), 2.79 (3H, s, Ph-CH3), 3.48-3.56 (4H, q, J
= 7.0 Hz, N(CH2CH3)2, 3.82 (3H, s, COOCH3), 4.98 (2H, s, NCH2), 6.69-6.78 (2H,
3¢-H, 5¢-H), 7.83-7.89 (1H, J = 7.4 Hz, 6-H), 7.97-8.05 (2H, 6¢-H, 5-H), 8.65-8.698
(2H, 2-H, 7-H), 9.27-9.31 (1H, J = 8.5 Hz, 3-H);
FTIR (KBr): n 2970.25 cm-1 (C-H str. Ar.), 2928.32 cm-1 (C-H str. Aliphatic),
1748.91 cm-1 (C=O str. ester), 1693.74, 1649.56 cm-1 (C=O str. carbonyl), 1589.74
cm-1 (N=N str.);
Anal. Calcd for C26H26N4O4: C, 68.12%; H, 5.68%; N, 12.22%; Found: C, 68.25%;
H, 5.27%; N, 12.56%.
7
1H NMR (CDCl3): 1.27-1.34 (9H, t, CH2CH3), 3.50-3.57 (4H, q, J = 6.9,
N(CH2CH3)2), 4.24-4.31 (2H, q, J = 7.1 Hz, COOCH2CH3), 4.98 (2H, s, N-CH2),
6.79-6.82 (2H, 3¢-H, 5¢-H), 7.83-7.89 (1H,J = 8.3, 6-H), 7.97-8.06 (3H, 2¢-H, 6¢-H,
5-H), 8.66-8.70 (2H, 2-H, 7-H), 9.28-9.31 (1H, d, J = 8.6 Hz, 3-H);
FTIR (KBr): n 2960.77 (C-H str. Ar.), 2924.95 cm-1 (C-H str. Aliphatic), 1748.4 cm-
1 (C=O str. ester), 1698.61 cm-1, 1662.05 cm-1 (C=O str. Carbonyl), 1596.4 cm-1
(N=N str.);
Anal. Calcd for C26H26N4O4: C, 68.12%; H, 5.68%; N, 12.2%; Found: C, 68.1%; H,
5.6%; N, 11.5%.
mp = 201.27 °C
8
1H NMR (CDCl3): 1.27-1.34 (9H, CH3), 2.79 (3H, s, Ph-CH3), 3.48-3.55 (4H, q, J =
7.0 Hz, N(CH2CH3)2), 4.24-4.31 (2H, q, J = 7.1 Hz, COOCH2CH3), 4.98 (2H, s,
NCH2), 6.60-6.65 (2H, 3¢-H, 5¢-H), 7.82-7.87 (1H, J = 7.4 Hz, 6-H), 7.96-8.03 (2H,
6¢-H, 5-H), 8.65-8.69 (2H, 2-H, 7-H), 9.32-9.35 (1H, d, J = 8.4 Hz, 3-H.);
FTIR (KBr): n 2972.25 cm-1 (C-H str. Ar.), 2932.22 cm-1 (C-H str. Aliphatic),
1752.02 cm-1 (C=O str. ester), 1695.59, 1659.37 cm-1 (C=O str. carbonyl), 1588.21
cm-1 (N=N str.);
Anal. Calcd for C27H28N4O4: C, 68.64%; H, 5.93%; N, 11.86%; Found: C, 68.8%; H,
6%; N, 11.8%.
mp = 202.38 °C
9
1H NMR (CDCl3): 1.27-1.34 (9H, CH3), 1.61 (1H, NHCOCH3, D2O exchangeable),
2.35 (3H, NHCOCH3), 3.52-3.59 (4H, q, J = 6.7 Hz, N(CH2CH3)2), 4.24-4.31 (2H,
q, J = 6.9 Hz, COOCH2CH3), 4.98 (2H, N-CH2), 6.54-6.56 (1H, d, J = 7.7 Hz, 5¢-H),
7.82-7.96 (3H, 6-H, 5-H, 6¢-H), 8.18 (1H, s, 3¢-H), 8.65-8.70 (2H, 2-H, 7-H), 9.12-
9.15 (1H, d, J = 8.0 Hz, 3-H).
FTIR (KBr): n 2976.64 cm-1 (C-H str. Ar.), 2930.82 cm-1 (C-H str. Aliphatic),
1747.05 cm-1 (C=O str. ester), 1697.99, 1658.53 Cm-1 (C=O str. Carbonyl), 1588.77
cm-1 (N=N str.);
Anal. Calcd for C28H29N5O5: C, 65.24%; H, 5.63%; N, 13.59%; Found: C, 65.1%; H,
5.8%; N, 13.4%
mp = 276.11 °C
cient and reflectance of dyed sample, respectively. Fig. 3
(K/S vs. concentration) shows the synthesized dyestuffs
had very good buildup on polyester fabric except for dye-
stuff 5. K/S is taken as criteria for dyeability of polyester
fibres. As is clear from Fig. 3, they generally reached satu-
ration at concentrations of 1-1.5% owf. The rate and degree

Novel Monoazo Naphthalimide Dyestuffs
J. Chin. Chem. Soc., Vol. 54, No. 4, 2007 1027
Table 4. Spectral data of synthesized dyestuffs
Chloroform
Dyestuffs
Toluene
DMF
Dlmax (nm)
lmax (nm)
lmax (nm)
lmax (nm)
Î (l/mol.cm)
5
6
7
8
9
529.7
536.6
528.5
538.7
554.6
37637
38233
36983
33196
49080
515.1
524.1
514.8
523.6
544.5
539.7
549.0
547.0
554.7
563.4
24.6
24.9
32.2
31.1
18.9
of exhaustion of dyestuffs (5-8) were good, but dyestuff 9
had poor exhaustion. The introduction of an acetyl group
at the 3-position on N,N-diethylaniline produced a pro-
nounced bathochromic shift but had little effect on the ex-
haustion.
of the coupling components also considerably affect the
color of the dyeings. The presence of strongly electron do-
nor substituents in dyestuff 9 caused a color shift towards
bluish. The color hues of the dyestuffs 6 and 8 on polyester
fabrics are shifted towards bluish red or violets, but less
than with dyestuff 5. The methyl group in the 3-position of
The wash fastness properties (ISO 105 C06C2S) of
dyestuffs 5-9 expressed as colour change of the fabric sam-
ples and staining on cotton and polyester were excellent
(4-5 to 5). The presence of the ester group on naphtha-
limide moiety was not an influencing parameter in deter-
mining wash fastness performance.16 Also there is the pos-
sibility of the hydrolyzing ester group in alkaline washing
media, which produces alkali-soluble carboxylic acid dye-
stuffs.
Table 5. Colour fastness of the synthesized dyestuffs
Wash fastness
Heat fastness
Light
Dyestuffs
Pa
Ca
Change
180 °C
fastness
5
6
7
8
9
5
5
5
5
4-5
5
4
4-5
3-4
4
4
4-5
5
4-5
5
5
3-4
3-4
3-4
5
4
The dry heat fastness and light fastness were mea-
sured according to ISO standards 105 X11:1994(E) and
ISO 105 B02, respectively. The synthesized dyestuffs showed
moderate to very good dry heat fastness at 180 °C and mod-
erate light fastness.
4
4
4-5
5
a: Staining, P: Polyester, C: Cotton, b: Staining on polyester,
Washfastness and Heatfastness: 1 to 5 shows poor to excellent
fastne-ss, respectively.
Lightfastness: 1 to 8 represents poor to ideal light fastness,
spectively.
The color of the dyed fabrics was assessed by a re-
flectance spectrophotometer (Table 5). The results showed
that introducing the electron donor substituents in the ring
Table 6. Spectrophotometric data of synthesized dyestuffs
Dyestuff
1
(% owf)
L*
a*
b*
0.3
0.7
2
31.895
27.233
24.321
49.508
19.153
17.499
36.443
29.980
21.655
40.909
22.413
21.575
43.727
39.833
38.010
40.856
37.388
33.938
35.316
25.239
18.816
39.405
38.371
29.129
33.793
28.763
26.817
27.037
27.450
25.980
-10.684
-7.514
-4.665
2
3
4
5
0.3
0.7
2
-25.340
-9.002
-4.833
0.3
0.7
2
-11.352
-7.780
-1.919
0.3
0.7
2
-25.188
-16.419
-14.945
-30.686
-28.519
-23.282
0.3
0.7
2
Fig. 3. Build up of the synthesized dyestuffs, K/S: Ap-
proximate concentration of each dye in the sub-
strate.
L* = Lightness, a* and b* = chromaticity coordinate

1028 J. Chin. Chem. Soc., Vol. 54, No. 4, 2007
Gharanjig et al.
N,N-diethylaniline in dyestuffs 6 and 8, which is a weak
electron donor, caused a shift less than dyestuff 9. The
spectrophotometric data showed that the nature of the ester
residue in N-substituted-1,8-naphthalimide had little effect
on colour dyeings.
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CONCLUSIONS
A series of novel monoazo disperse dyestuffs based
on N-ester-1,8-naphthalimide were synthesized from ace-
naphthene as a starting material. Acenaphthene was ni-
trated and further reacted such as with oxidation, imida-
tion, reduction, diazotization and coupling. Data obtained
by various analytical techniques proved the synthesizing of
the claimed novel dyestuffs. The spectral characteristics of
the synthesized dyestuffs on polyester fabrics showed that
they give bluish-red with a relatively weak buildup for dye-
stuff 9, while the rest of the dyestuffs were very good on
polyester fabrics. For all the synthesized dyestuffs the wash
fastness properties were generally very good, whereas the
light fastness was moderate.
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Received August 10, 2006.