Synthesis of some novel biologically active disperse dyes derived from 4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine- 3-carbonitrile as coupling component and their colour assessment on polyester fabrics

Article abstract of DOI:10.3390/molecules17088822

A series of novel azo-disperse dyes containing alkylhydrazonopyridinone structures were synthesized. 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6- tetrahydropyridine-3- carbonitrile (8) is synthesized by one-pot synthesis using ethyl cyanoacetate, propylamine, and ethyl acetoacetate. Compound 8 is then coupled with aromatic and heteroaromatic diazonium salts to afford the corresponding aryl- and heteroaryl-4-methyl-2,6-dioxo-1- propyl-1,2,5,6- tetrahydropyridine-3-carbonitriles 12a,b and 13a-c. Structural assignments to the dyes were made using NMR spectroscopic methods. A high temperature dyeing method was employed to apply these dyes to polyester fabrics. Most of the dyed fabrics tested displayed very good light fastness levels and good wash fastness. Finally, the biological activity of the prepared dyes against Gram positive bacteria and Gram negative bacteria were evaluated.

Full text of DOI:10.3390/molecules17088822

Molecules 2012, 17, 8822-8831; doi:10.3390/molecules17088822
OPEN ACCESS
molecules
ISSN 1420-3049
www.mdpi.com/journal/molecules
Article
Synthesis of Some Novel Biologically Active Disperse Dyes
Derived from 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydro-
pyridine-3-carbonitrile as Coupling Component and Their
Colour Assessment on Polyester Fabrics
Samar M. Ashkar 1, Morsy A. El-Apasery 2,*, Marwan M. Touma 1 and Mohamed H. Elnagdi 3
1
Department of Chemistry, Faculty of Science, University of Aleppo, P.O. Box 10229, Aleppo, Syria
2
Dyeing, Printing and Textile Auxiliaries Department, Textile Research Division,
National Research Centre, Dokki, Giza 12622, Egypt
3
Chemistry Department, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait
* Author to whom correspondence should be addressed; E-Mail: elapaserym@yahoo.com.
Received: 7 June 2012; in revised form: 14 July 2012 / Accepted: 21 July 2012 /
Published: 25 July 2012
Abstract: A series of novel azo-disperse dyes containing alkylhydrazonopyridinone
structures were synthesized. 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-
carbonitrile (8) is synthesized by one-pot synthesis using ethyl cyanoacetate, propylamine,
and ethyl acetoacetate. Compound 8 is then coupled with aromatic and heteroaromatic
diazonium salts to afford the corresponding aryl- and heteroaryl-4-methyl-2,6-dioxo-1-
propyl-1,2,5,6-tetrahydropyridine-3-carbonitriles 12a,b and 13a–c. Structural assignments
to the dyes were made using NMR spectroscopic methods. A high temperature dyeing
method was employed to apply these dyes to polyester fabrics. Most of the dyed fabrics
tested displayed very good light fastness levels and good wash fastness. Finally, the
biological activity of the prepared dyes against Gram positive bacteria and Gram negative
bacteria were evaluated.
Keywords: arylhydrazonopyridinones; biological activity; disperse dyes; polyester fabrics

Molecules 2012, 17
8823
1. Introduction
Arylhydrazonopyridinones are now replacing arylazopyrazolones in the classical dye industry.
Moreover, reasonable solubility of these derivatives in lipophilic solvents gives these dyes high
potential for utilization in dye diffusion thermal transfer printing [1]. Pyridinone derivatives are
relatively recent heterocyclic intermediates for the preparation of dyes. The azopyridinone dyes give
bright hues and are therefore of investigative interest [2]. Owing to their improved brightness and light
fastness, pyridinone disperse dye derivatives have found many applications on different fibres [3–8].
Moreover, the pyridinone nucleus has been proven to constitute the active part of several
biologically active compounds [9,10]. Keeping in mind the biological importance of the above
mentioned heterocyclic compounds and in continuation to our endeavor towards environmentally
benign synthesis [11–17], we report herein the synthesis of 4-methyl-2,6-dioxo-1-propyl-1,2,5,6-
tetrahydro-pyridine-3-carbonitrile (8) as a good precursor to novel aryl- and heteroaryl-4-methyl-2,6-
dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitriles and their application as disperse dyes for the
dyeing of polyester fabrics. The antibacterial activities of these dyes were also studied.
2. Results and Discussion
2.1. Synthesis and Characteristics
Our initial strategy aimed to synthesize the alkylhydrazonopyridinone 8 and convert it to the
corresponding aryl- or heteroaryl-4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbo-
nitriles 12a,b and 13a–c, which were anticipated to be excellent new disperse dyes for the dyeing of
polyester fabrics employing a high temperature dyeing method. We introduce a one-pot three
component condensation for the synthesis of alkylhydrazonopyridinone 8 under reflux and solvent-free
conditions. Thus, the reaction of ethyl acetoacetate, ethyl cyanoacetate, and propyl amineunder reflux
without solvent for 6 hours afforded compound 8 in good yield. The product was identified by IR and
1H-NMR spectroscopic data. Compound 8 may be exist in another tautmeric form 9 and in solution
there is a very fast equilibrium between them [18,19]. The structure of compound 9 in solution was
confirmed based on the basis of 1H-NMR spectral data (presence of a pyridonyl-H signal at δ 7.67 and
hydroxyl group signal at δ 14.63, respectively).
It seems that the in-situ reaction of alkylcyanoester 1 and primary amine 2 leads to amide derivative
4 and reaction with β-ketoester 5 then gives 4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-
carbonitrile (8) in high yield. The formation of compound 8 is assumed to proceed via intermediacy of
3, 4, 6 and 7. The one-pot nature of the present procedure makes it an acceptable alternative to
multistep approaches. It also simplifies the laborious procedures and offers considerable advantages
over the existing methodologies, such as elimination of solvent, high yield, and environmentally
friendly character (cf. Scheme 1).

Molecules 2012, 17
8824
Scheme 1. Preparation of 4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitrile (8).
O
O
C
..
+
NC CH2
C
O
C2H5
H2N C3H7
NC CH2
O C2H5
1
2
NH2C3H7
3
CH3
C
O
H2C
CH2 CN
O
O
C
O
C
O
O
C
H3C C CH2
O
C2H5
NC CH2
C NHC3H7
..
N
H
C2H5O
5
4
C3H7
6
C H OH
-
2
5
CH3
C
O
CH3
CH3
H2C
C
CH2 CN
CN
O
CN
O
-
H2O
C
O
O
O
N
HO
N
N
C3H7
C3H7
C3H7
8
9
7
Coupling of compound 8 with aromatic and heteroaromatic diazonium salts (Ar and Het,
respectively) afforded the corresponding aryl- and heteroaryl-4-methyl-2,6-dioxo-1-propyl-1,2,5,6-
tetrahydropyridine-3-carbonitriles 12a,b and 13a–c. Structural assignments to these dyes were made
using NMR spectroscopic methods (cf. Scheme 2).
Scheme 2. Synthesis of some novel biologically active disperse dyes 12a,b and 13a–c.
H
N
CH3
CH3
H
N
CH3
Het
N
O
CN
O
CN
O
Ar
Het
N
O
CN
O
N
NCl
Ar
N
NCl
11
10
N
O
N
N
C3H7
C3H7
C3H7
8
13
12
H
N
CH3
S
H
CH3
N
O
CN
O
N
HO
N
N
CN
N
O
N
O
C3H7
13a
C3H7
H
N
CH3
12a
N
O
CN
O
H
N
CH3
N
H3C
N
O
CN
O
O
H3C
N
C3H7
N
13b
C3H7
H
N
CH3
12b
N
CN
O
N
N
N
H
H3C
S
O
N
C3H7
13c

Molecules 2012, 17
8825
2.2. Dyeing and Fastness Properties
Disperse dyes 12a,b and 13a,b were applied to polyester fabrics at 1% o.w.f., using high temperature
dyeing method (HT) at 130 °C. Dark orange, yellow, orange and light green color shades were obtained.
The dyeing properties on the polyester fabrics were evaluated in terms of their fastness properties (e.g.,
fastnesses to washing and light). The color of dyeing on polyester fabrics is expressed in terms of CIELAB
values (Table 1), and the following CIELAB coordinates were measured: lightness (L*); chroma (C*); hue
angle (H) from 0 to 360°; a*, whose value represents the degree of redness (positive) and greenness
(negative); and b*, whose value represents the degree of yellowness (positive) and blueness (negative).
Table 1. Optical measurements of the synthesized dyes on the polyester fabrics.
Dye No.
12a
12b
13a
13b
DL*
Da*
40.68
7.24
18.14
−8.06
Db*
DC*
Dh*
CMC dE
126.14
131.81
114.79
48.89
−25.66
−14.95
−22.16
−13.22
84.09
97.52
83.08
42.03
92.89
97.63
84.77
36.13
−9.82
−5.52
−6.75
−0.37
In general, the color hues of the dye 13b on the polyester fabric shifted in the greenish direction;
this was indicated by the negative values of a* (red–green axis). The positive values of b* (yellow–
blue axis) indicated that the color hues of the dyes 12a, 12b and 13a on the polyester fabric shifted to
the yellowish direction.
The physical data for the dyed fibers, given in Table 2, shows that the disperse dyeing displayed
good wash fastness properties to five multiple washes in terms of shade change and also very little
staining to the adjacent fiber strip occurred. Table 2, shows that the light fastness is very good with
respect to most of the tested compounds, except compound 13a (1% o.w.f) which showed good results.
Table 2. Shade and Fastness properties of azo disperse dyes on polyester fabrics.
Dye
No.
12a
Wash fastness *
Washes Change in colour
Color shade on
polyester
Dark orange
Light
fastness
7–8
SC
5
4
4
4
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
4–5
3–4
3–4
3–4
3–4
4–5
4–5
4
4
4
4–5
4–5
4
4
5
12b
13a
Yellow
Orange
7
4–5
4–5
4–5
4–5
5
4–5
4–5
4–5
4–5
5–6
4
4

Molecules 2012, 17
8826
Table 2. Cont.
Wash fastness *
Washes Change in colour
Dye
No.
13b
Color shade on
polyester
Light
fastness
6–7
SC
5
4
4
4
Light green
1
2
3
4
5
4–5
4
4
4
4
4
* SC = staining on cotton.
2.3. Antimicrobial Activities
The antimicrobial activities of the synthesized dyes were screened against selected bacteria
by the agar well diffusion method and their inhibition zones diameters, given in Table 3,
reveal that three of the tested dyes showed positive antimicrobial activities against at least one
of the tested microorganisms. Two dyes, 12a and 13a showed strong activities, while two dyes 13b
and 13c showed moderate activities with significant inhibition zones >10 mm, against Staphylococcus
auerus and Bacillus subtilus (Gram positive bacteria). It is worth mention here that dye 12b has
showed no antimicrobial activities against any of the tested microorganisms, and all the dyes have no
antimicrobial activities against Escherichia coli, Klebsiellae pneumoniae and Pseudomonas
aeruginosa (Gram negative bacteria).
Table 3. Diameter of the zones of inhibition of the tested compounds that showed weak to
strong antimicrobial against microorganisms.
Inhibition zone diameter (Nearest mm)
Dye Conc. %
Gram positive bacteria
Gram negative bacteria
No.
of Dye
S. aureus
B. subtilus
E. coli
K. pneumoniae P. aeruginosa
12a
12b
13a
13b
13c
12a
12b
13a
13b
13c
12a
12b
13a
13b
13c
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.25
mg/mL
-
-
-
-
-
-
-
-
-
-
0.50
mg/mL
16
-
16
-
-
-
18
-
13
-
1.00
mg/mL
20
-
19
14
10
10

Molecules 2012, 17
8827
Table 3. Cont.
Inhibition zone diameter (Nearest mm)
Dye Conc. %
Gram positive bacteria
Gram negative bacteria
K. pneumoniae P. Aeruginosa
No.
of Dye
S. aureus
B. subtilus
E. coli
12a
12b
13a
13b
13c
12a
12b
13a
13b
13c
21
-
18
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
2.00
mg/mL
24
-
12
25
-
20
15
12
22
-
3.00
mg/mL
30
-
22
17
16
16
(-): No inhibition.
The results obtained for the synthesized compounds in this study support the findings of the other
researchers [9] who showed that alkylhydrazonopyridinones cores have various biological activities.
alkylhydrazonopyridinones were proved to possess biological effects, including antimicrobial
activities [10]. Therefore, the new synthesized classes showed promising results for possessing the
potentials to be utilized for medicinal purposes.
3. Experimental
3.1. General
Melting points were recorded on a Gallenkamp apparatus. IR spectra were recorded using KBr
1
13
pellets on a Jasco FTIR-6300 FT-IR spectrophotometer. H and C-NMR spectra were recorded on
Bruker DPX 400 MHz. The colorimetric parameters of the dyed polyester fibers were determined on a
reflectance spectrophotometer (Datacolor SF 600X Spectraflash, Switzerland). Mass spectra were
measured on a high resolution GC/MS DFS-Thermo. Microanalyses were performed on Elementar-
Vario Micro cube Analyzer.
3.2. Synthesis of 4-Methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitrile (8)
A mixture of ethyl acetoacetate (26.00 g, 0.2 mol), ethyl cyanoacetate (22.62 g, 0.2 mol),
propylamine (11.82 g, 0.2 mol) was refluxed until the reaction was completed (about 6 h). During the
reaction, the white product precipitated. The crude product was filtered, dried and recrystallized from
ethanol to give white crystals (82%), m.p. 218–220 °C, IR (KBr): 2217 (CN) and 1735 (CO) cm−1;
1H-NMR (400 MHz, DMSO-d6): δ = 0.85 (t, J = 7 Hz, 3H, CH3CH2), 1.49 (m, 2H, CH2), 2.39 (s, 3H,
CH3), 3.69 (s, 2H, CH2N), 7.67 (s, 1H, CH), 14.63 (br, 1H, OH, D2O exchangeable); MS (EI):
m/z(%) = 193 ([M+1]+, 56). 151 (12), 120 (5), 94 (7).

Molecules 2012, 17
8828
3.3. General Procedure for the Synthesis of Azo Disperse Dyes
A cold solution of arenediazonium salt (10 mmol) was prepared by adding a solution of sodium
nitrite (1.00 g in 10 mL H2O) to a cold solution of aryl amine hydrochloride or aryl amine nitrate
(10 mmol) with stirring as described earlier. The resulting solution of the arenediazonium was then
added to a cold solution of compound 8 (10 mmol) in ethanol (20 mL) containing sodium acetate (2.00 g).
The mixture was stirred at room temperature for 1 h and the solid product so formed was collected by
filtration and recrystallized from ethanol to give compounds 12a,b and 13a–c, respectively.
5-[(4-Hydroxyphenyl)-hydrazono]-4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbo-nitrile
(12a). Red crystals from toluene (88%), m.p. 252–255 °C, IR (KBr): 3407 (OH), 2222 (CN) and 1657
1
(CO) cm−1; H-NMR (400 MHz, DMSO-d6): δ = 0.85 (t, J = 7 Hz, 3H, CH3CH2), 1.51 (m, 2H, CH2),
2.45 (s, 3H, CH3), 3.78 (t, J = 7 Hz, 2H, CH2N), 6.86 (d, J = 7 Hz, 2H, arom-H), 7.55 (d, J = 7 Hz, 2H,
13
arom-H), 10.02 (br, 1H, OH, D2O exchangeable) 14.84 (br, 1H, NH, D2O exchangeable); C-NMR
(DMSO-d6): δ = 160.5, 160.0 (2CO), 158.7, 157.5, 133.0, 121.5, 119.2, 116.3, 115.4, 98.2, 29.3 (CH2),
20.4 (CH2). 16.1 (CH3), 11.2 (CH3). MS (EI): m/z (%) = 312 ([M]+, 100). 295 (8), 270 (52), 121 (24),
108 (43), 93 (24). HRMS: m/z (EI) for C16H16N4O3; calcd. 312.1216; found: 312.1216.
4-Methyl-2,6-dioxo-1-propyl-5-(p-tolylhydrazono)-1,2,5,6-tetrahydropyridine-3-carbonitrile
(12b).
Yellow crystals from ethanol (86%), m.p. 215–218 °C, IR (KBr): 3432 (NH), 2223 (CN) and 1679
1
(CO) cm−1; H-NMR (400 MHz, DMSO-d6): δ = 0.88 (t, J = 7 Hz, 3H, CH3CH2), 1.52 (m, 2H, CH2),
2.32 (s, 3H, CH3), 2.50 (s, 3H, CH3), 3.78 (t, J = 7 Hz, 2H, CH2N), 7.27 (d, J = 7 Hz, 2H, arom-H),
7.58 (d, J = 7 Hz, 2H, arom-H), 14.62 (s, 1H, NH, D2O exchangeable); MS (EI): m/z (%) = 310
([M]+, 100). 293 (9), 268 (26), 177 (12), 106 (32), 91 (56). HRMS: m/z (EI) for C17H18N4O2; calcd.
310.1424; found: 310.1424.
4-Methyl-2,6-dioxo-1-propyl-5-(thiazol-2-yl-hydrazono)-1,2,5,6-tetrahydropyridine-3-carbonitrile (13a).
Yellow crystals from toluene (65%), m.p. 210 °C, IR (KBr): 3405 (NH), 2224 (CN) and 1684 (CO)
1
cm−1; H-NMR (400 MHz, DMSO-d6): δ = 0.87 (t, J = 7 Hz, 3H, CH3CH2), 1.50 (m, 2H, CH2), 2.47
(s, 3H, CH3), 3.79 (t, J = 7 Hz, 2H, CH2N), 7.48 (d, J = 7 Hz, 1H, arom-H), 7.67 (d, J = 7 Hz, 1H,
arom-H), MS (EI): m/z(%) = 303 ([M]+, 100). 288 (7), 218 (12), 190 (90), 149 (17), 86 (27). HRMS:
m/z(EI) for C13H13N5O2S; calcd. 303.0782; found: 303.0782.
4-Methyl-5-[(5-methylisoxazol-3-yl)-hydrazono]-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-
carbonitrile (13b). Yellowish-green crystals from ethanol (80%), m.p. 266–268 °C, IR (KBr): 3429
1
(NH), 2225 (CN) and 1688 (CO) cm−1; H-NMR (400 MHz, DMSO-d6): δ = 0.88 (t, J = 7 Hz, 3H,
CH3CH2), 1.51 (m, 2H, CH2), 2.44 (s, 3H, CH3), 2.45 (s, 3H, CH3), 3.79 (t, J = 7 Hz, 2H, CH2N), 6.67
(s, 1H, arom-H), 14.24, 14.62 (s, 1H, NH, D2O exchangeable); MS (EI): m/z (%) = 301 ([M]+, 100).
286 (8), 216 (52), 190 (72), 149 (42), 68 (42). HRMS: m/z (EI) for C14H15N5O3; calcd. 301.1163;
found: 301.1163.

Molecules 2012, 17
8829
4-Methyl-5-[(5-methylsulfanyl-1H-[1,2,4]triazol-3-yl)-hydrazono]-2,6-dioxo-1-propyl-1,2,5,6-tetra-
hydropyridine-3-carbonitrile (13c). Yellow crystals from ethanol (82%), m.p. 271–272 °C, IR (KBr):
1
3431 (NH), 2232 (CN) and 1684 (CO) cm−1; H-NMR (400 MHz, DMSO-d6): δ = 0.88 (t, J = 7 Hz,
3H, CH3CH2), 1.51 (m, 2H, CH2), 2.47 (s, 3H, CH3), 2.50 (s, 3H, CH3), 3.78 (t, J = 7 Hz, 2H, CH2N),
14.20 (s, 1H, NH), 14.60 (s, 1H, triazolyl-NH), MS (EI): m/z (%) = 333 ([M]+, 100). 291 (12), 256
(12), 205 (32), 149 (12), 97 (36). HRMS: m/z (EI) for C13H15N7O2S; calcd. 333.1002; found: 333.1002.
3.4. High Temperature Dyeing Method (HT)
3.4.1. Materials
Scoured and bleached polyester 100% was used. The fabric was treated before dyeing with a
solution containing non-ionic detergent (5 g/L) and sodium carbonate (2 g/L) in a ratio of 50:1 at 60 °C
for 30 min, then thoroughly washed with water and air dried at room temperature.
3.4.2. Dyeing
The dye baths were prepared from the dye (1.0% weight of fibre) to a final liquor of 40:1, w/w. The
pH value of the bath was adjusted to 4–5 with acetic acid (10%). The polyester fabrics, previously
wetted, were placed into the liquor at 25 °C–30 °C. The temperature was raised to 130 °C at the rate of
2 °C/min, and dyeing continued for 60 min. After cooling, the dyed fabrics were then washed and
dried [20].
3.4.3. Color Assessment
The colorimetric parameters (Table 1) of the dyed polyester fibers were determined on a reflectance
spectrophotometer (Datacolor SF 600X) equipped with a D65 source.
3.5. Fastness Testing
The dyed fabrics were tested, employing ISO standard methods [21]. Wash fastness tests were
carried out in accordance with ISO: 105-C01-C05:1989(E):Test 1–5, ISO: 105-A02:1993(E) and
ISO: 105-A03:1993(E). Daylight fastness was carried out in accordance with ISO: 105-B01:1994.
3.6. Antimicrobial Activities Test
The antimicrobial activities of four disperse dyes were tested against five different microbial
cultures using the agar-well diffusion technique [22]. Pure cultures of Staphylococcus auerus and
Bacillus subtilus (Gram positive bacteria), Escherichia coli, Klebsiellae pneumoniae and Pseudomonas
aeruginosa (Gram negative bacteria) were employed in the test. An aliquot of each bacterial strain
(0.1 mL) was inoculated and spread on nutrient agar (NA). The inoculated plates were supplied with
100 µL of each of the tested dyes with concentrations of 0.25, 0.50, 1.00, 2.00 and 3.00 mg·mL−1. The
dyes were placed in 4 mm wells produced by sterile cork borer. The NA plates were incubated at 37 C
for 24 h. The zones of inhibition around the wells were determined and the averages based on three
replicas were recorded.

Molecules 2012, 17
8830
4. Conclusions
In summary, 4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-carbonitrile (8) was
synthesized by one-pot synthesis using ethyl cyanoacetate, propylamine, and ethyl acetoacetate.
Compound 8 is then coupled with aromatic and heteroaromatic diazonium salts to afford
the corresponding aryl- and heteroaryl-4-methyl-2,6-dioxo-1-propyl-1,2,5,6-tetrahydropyridine-3-
carbonitriles. The dyes produced in this manner were then applied to polyester fabrics by using a HT
dyeing method. The dyed fabrics, which displayed yellow to light green hues on polyester fabrics,
have very good fastness level to light and good fastness to wash. Finally, the biological activity of the
synthesized dyes against Gram positive bacteria, Gram negative bacteria was discussed.
References
1. Al-Zaydi, K.M.; Borik, R.M.; Elnagdi, M.H. Studies with arylhydrazonopyridinones: Synthesis of
new arylhydrazono thieno[3,4-c]pyridinones as novel D2T2 dye class; classical verse green
methodologies. Ultrason. Sonochem. 2009, 16, 660–668.
2. Helal, M.H. Synthesis and characterisation of a new series of pyridinone azo dyes for dyeing of
synthetic fibers. Pigm. Resin Technol. 2004, 33, 165–171.
3. Desai, V.R.; Patel, D.; Desai, C.M.; Joshi, H.D. Sulphaphenazolamino-anthraquinone acid,
reactive and substituted pyridone disperse dyes-part I. J. Inst. Chem. (India) 2000, 72, 228–229.
4. Bach, V.; Hansen, G.; Lamm, G.; Sens, R. [(Acylphenyl)azo]pyridone disperse dyes and their use.
Eur. Pat. 1991, Appl. 413229.
5. Sakoma, K.J.; Bello, K.A.; Yakubu, M.K. Synthesis of Some Azo Disperse Dyes from
1-Substituted 2-Hydroxy-6-pyridone Derivatives and Their Colour Assessment on Polyester
Fabric. Open J. Appl. Sci. 2012, 2, 54–59.
6. Bello, K.A. Methine and Azomethine Dyes Derived from 2-Pyridone. Dyes Pigments 1995, 28,
83–90.
7. Chien, C.C.; Wang, I.J. Synthesis of Some Pyridone Azo Dyes from 1-Substituted 2-Hydroxy-6-
pyridone Derivatives and Their Colour Assessment. Dyes Pigments 1991, 15, 69–82.
8. Ertan, N.; Gurkan, P. Synthesis and Properties of Some Azo Pyridone Dyes and Their Cu(II)
Complexes. Dyes Pigments 1997, 33, 137–147.
9. El-Bayouki, M.; Abdel Hameed, K.; Asyouni, W.M.; Mohamed, Y.A.; Aly, M.M.; Abbas, S.Y.
Novel 4(3H)-quinazolinones containing biologically active thiazole, pyridinone and chromene of
expected antitumor and antifungal activities. Eur. J. Chem. 2011, 2, 455–462.
10. Afanas'Ev, I.I.; Korkina, L.G.; Kozlov, A.V.; Afanas'Ev, I.B. Spectrophotometric, electron spin
resonance, polarographic, and chemiluminescent study of biologically active chelators: 1-Allyl-2-
methyl-3-hydroxy-4-pyridinone, lipoic and dihydrolipoic acids. Phys. Chem. Biol. Med. 1996, 3,
25–30.
11. El-Dusouqui, O.M.E.; Abdelkhalik, M.M.; Al-Awadi, N.A.; Dib, H.H.; George, B.J.;
Elnagdi, M.H. Chemistry of 2-arylhydrazonals: utility of substituted 2-arylhydrazono-3-
oxoalkanals as precursors for 3-oxoalkanonitriles, 3-aminoisoxazole and 1,2,3- and 1,2,4-
triazoles. J. Chem. Res. 2006, 5, 295–302.

Molecules 2012, 17
8831
12. Al-Etaibi, A.M.; El-Apasery, M.A.; Huda, H.M. Al-Awadi, N.A. One-Pot Synthesis of Disperse
Dyes Under Microwave Irradiation: Dyebath Reuse in Dyeing of Polyester Fabrics. Molecules
2012, 17, 4266–4280.
13. Al-Etaibi, A.M.; Al-Awadi, N.A.; El-Apasery, M.A.; Ibrahim, M.R. Synthesis of some novel
pyrazolo[1,5-a]pyrimidine derivatives and their application as disperse dyes. Molecules 2011, 16,
5182–5193.
14. Al-Etaibi, A.M.; Al-Awadi, N.A.; El-Apasery, M.A.; Ibrahim, M.R. A facile synthesis of new
monoazo disperse dyes derived from 4-hydroxyphenylazopyrazole-5-amines: Evaluation of
microwave assisted dyeing behavior. Color. Technol. 2012, submitted for publication.
15. EI-Apasery, M.A.; Al-Mousawi, S.M.; Mahmoud, H.; Elnagdi, M.H. Novel routes to biologically
active enaminones, dienoic acid amides, arylazonicotinates and dihydropyridazines under
microwave irradiation. Int. Res. J. Pure Appl. Chem. 2011, 1, 69–83.
16. El-Apasery, M.A. Solvent-Free One-Pot Synthesis of Some Azo Disperse Dyes under Microwave
Irradiation: Dyeing of Polyester Fabrics. J. Appl. Polym. Sci. 2008, 109, 695–699.
17. El-Apasery, M.A. Synthesis of some azo disperse dyes by the use of focused microwave heating.
Pol. J. Appl. Chem. 2006, 50, 75–81.
18. Elguero, J.; Marzin, C.; Katritzky, A.R.; Linda, P. The Tautomerism of Heterocyles. In
Heterocyclic Chemistry; Academic Press: New York, NY, USA, 1976; pp. 106–109.
19. Balalaie, S.; Kowsari, E.; Hashtroudi, M.S. An Efficient Method for the Synthesis of 3-Cyano-6-
hydroxy-2(1H)-pyridinones under Microwave Irradiation and Solvent-free Conditions.
Chem. Mon. 2003, 134, 453–456.
20. Maradiya, H.R. Synthesis Of azobenzo[b]thiophen derivatives and their dyeing performance on
polyster fiber. Turk. J. Chem. 2001, 25, 441–450.
21. Chrysler, L.P. Methods of Test for Color Fastness of Textiles and Leather, 7th ed.; Bradford:
London, UK, 1990; pp. 89–94.
22. Dhingra, V.; Pakki, M.; Srinivas, R.; Narasu, L. Antimicrobial activity of artemisinin and its
precursors. Curr. Sci. 2000, 78, 708–713.
Sample Availability: Samples of the compounds 8, 12a,b and 13a–c are available from the authors.
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