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International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.9, No.06 pp 31-38, 2016
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Disperse Dyes Based on Pyrazolopyrimidinones I: Their Dyeing Applications and Antimicrobial Activities
Abu-Bakr A. A. M. El-Adasy1, Magda M. Kamel2, Mohamed O. Saleh1,
Abdel Haleem M. Hussein1, Morsy A. El-Apasery2*
1 Department of Chemistry, Faculty of Science, Al-Azhar University, Assiut, Egypt.
2 Dyeing, Printing and Textile Auxiliaries Department, Textile Research Division, National Research Centre, 33 El Buhouth St., Dokki, Cairo, Egypt.
Abstract : The goal of this study is to synthesize a series of disperse dyes based on pyrazolopyrimidinones. These dyes were synthesized by reaction of arylhydrazonopyrazolones with enaminones under acidic condition. Their structures were established by using Elemental analysis, FTIR, Mass, UV and NMR spectroscopy. These disperse dyes were applied to polyester fabrics, their fastness properties were tested. In addition, their biological activities against Gram negative and Gram positive bacteria were conducted.
Introduction
Disperse dyes are non-ionic dyes with sparing solubility in water. Disperse dyes are capable to retain comparatively better selectivity for hydrophobic fabrics, such as acetate, nylon and polyester. Moreover, disperse dyes have excellent tinctorial value. Azo disperse dyes are considered as class of organic colorants which consist of at least a conjugated chromophore azo group in association with one or more aromatic or heteroaromatic ring system 1. They are capable of producing high intensity color and have excellent technical properties2,3. The disperse dyes based on pyrazolopyrimidines and its derivatives have biological activities 4 and applicable for dyeing polyesters5,6,7,8. In continuation of our interest in synthesis of condensed pyrazolopyrimidinones new dyestuffs 9,10,11, the present study deals with efficient synthesis of condensed arylazopyrazolopyrimidinones disperse dyes and studying their dyeing properties on polyester fabrics. The antibacterial activity of pyrazolopyrimidinones disperse dyes against Gram negative and Gram positive bacteria was investigated.
Experimental
General
All melting points were determined on an electrothermal digital melting point apparatus and are uncorrected. The infrared spectra were recorded on IR-470 infrared spectrophotometer, Shimadzu; and Pye Unicam SP3-100 spectrophotometer using KBr pellet technique at Assiut University. 1H-NMR spectra were measured on a Varian 300 MHZ in deuterated dimethysulphoxide (DMSO-d6) using tetramethylsilane (TMS) as internal reference and the chemical shifts are expressed in ppm at Cairo University. Mass spectra were performed on HP model MS-5988 at Cairo University. Microanalyses for C, H, N and halogen were performed on a Vario El Elementar analyzer at Cairo University.
General Procedure for the Synthesis of azo Disperse Dyes 3a-e
A mixture of arylhydrazonopyrazolones (4.1, 0.02 M) and enaminones (3.5 g, 0.02 M) was dissolved in glacial acetic acid 5 mL and refluxed for 3 h. the formed solid was collected and crystallized from DMF/water to give dyes 3a-e.
7-Phenyl-3-phenylazo-pyrazolo[1,5-a]pyrimidin-2-one (3a)
Yield 3.3 g (51.4%), m.p. 206-208 ºC. IR (KBr): υ = 3435 cm-1(NH), 3025 cm-1 (CH-arom.), 1632 cm-1 (C=O of amid group), 1592 cm-1 (C=C). UV(DMSO) ƛmax= 425 nm. MS: m/z = 315 (M+, 88%), 238 (100%), 210 (36%), 128 (30%). 1H-NMR (DMSO-d6) 7.37 -7.78 (m, 10H, arom-H), 8.07 (d, 2H, J = 3.6 MHz, arom-H), 8.73 (d, 1H, J =4.8 MHz, NH). Anal. Calcd. For C18 H13N5O (315): C 68.57; H 4.13, N 22.22. Found: C 68.20; H 3.59; N 22.10.
7-Phenyl-3-p-tolylazo-pyrazolo[1,5-a]pyrimidin-2-one (3b).
Yield 4.2 g (67.14%), m.p. 235-237 ºC. IR (KBr): υ = 3493 cm-1(NH), 3035 cm-1 (CH-arom.) , 2930 cm-1 (CH-aliph.), 1632 cm-1 (C=O of amid group), 1578 cm-1 (C=C).UV(DMSO) ƛmax= 428 nm. MS: m/z = 328 (M+, 94%), 315 (14%), 252 (75%), 224 (33%). 1H-NMR (DMSO-d6) 2.35 (s, 3H, CH3), 7.29 (d, 2H, J = 8.1MHz, arom-H), 7.45 (d, 2H, J = 4.8 MHz, arom-H), 7.56-7.68 (m,5H,arom-H), 8.05 (d, 2H, J = 8.4 MHz, arom-H), 8.70 (d, 1H, J = 4.8 MHz, NH). Anal. Calcd. for C19H15 N5O (328): C 69.30; H 4.56, N 21.27. Found: C 68.80; H 4.05; N 21.20.
3-(4-Chloro-phenylazo)-7-phenyl-pyrazolo[1,5-a]pyrimidin-2-one (3c).
Yield 5.4 g (77.8%), m.p. 246-248 ºC. IR (KBr): υ = 3443 cm-1(NH), 3061 cm-1 (CH-arom.), 1633 cm-1 (C=O of amid group), 1601 cm-1 (C=C). UV(DMSO) ƛmax= 423 nm. MS: m/z = 349.5 (M+, 73%), 238 (100%), 210 (34%), 128 (58%). 1H-NMR (DMSO-d6) 7.46 (d, 2H, J = 4.8 MHz, arom-H), 7.54-7.64 (m, 5H, arom-H), 7.79 (d, 2H, J = 8.7 MHz, arom-H), 8.06 (d, 2H, J = 8.4, arom-H), 8.73 (d, 1H, J =4.8 MHz, NH). Anal. Calcd. for C18H12 N5OCl (349.5): C 61.80; H 3.43, N 20.03. Found: C 61.51; H 3.15; N 20.25.
3-(4-Bromo-phenylazo)-7-phenyl-pyrazolo[1,5-a]pyrimidin-2-one (3d).
Yield 6.4 g (81.6%), m.p. 267-269 ºC. IR (KBr): υ = 3446.43 cm-1(NH), 3054 cm-1 (CH-arom.) , 1645 cm-1 (C=O of amid group), 1621 cm-1 (C=C).UV(DMSO) ƛmax= 417 nm. MS: m/z = 394 (M+, 36%), 238 (94%), 210 (32%), 182 (28%). 1H-NMR (DMSO-d6) 7.47 (d, 2H, J =4.8 MHz, arom-H), 7.61 (d, 2H, J =5.10 MHz, arom-H), 7.67-7.74 (m, 5H, arom-H), 8.05 (d, 2H, J = 7.8MHz, arom-H), 8.73 (d, 1H, J = 4.8 MHz, NH). Anal. Calcd. for C18H12 N5OBr (394): C 54.82; H 3.05, N 17.77. Found: C 55.00; H 2.75; N 17.40.
3-(4-Nitro-phenylazo)-7-phenyl-pyrazolo[1,5-a]pyrimidin-2-one (3e).
Yield 3.4 g (61.4%), m.p. > 300 ºC. IR (KBr): υ = 3415 cm-1(NH), 3067 cm-1 (CH-arom.) , 1644.21 cm-1 (C=O of amid group), 1606 cm-1 (C=C). UV(DMSO) ƛmax= 425 nm. MS: m/z = 360 (M+, 49%), 238 (56%), 210 (18%), 182 (14%). 1H-NMR (DMSO-d6) 7.67 (m, 5H, arom-H), 7.91 (d, 2H, J =8.70 MHz, arom-H), 8.07 (d, 2H, J = 4.8 MHz, arom-H), 8.33 (d, 2H, J = 7.8 MHz, arom-H), 7.78 (d, 1H, J = 4.2 MHz, NH). Anal. Calcd. for C18H12 N6O3 (360): C 60.00; H 3.34, N 23.34. Found: C 59.39; H 2.90; N 23.50.
Fabrics
Scoured and bleached 100% polyester fabric was supplied by El-Mahalla El-Kobra Company, Egypt. The fabrics were scoured in aqueous solution having a liquor ratio of 1:50 and containing 2 g/L of nonionic detergent solution (Hostapal; Clariant, Swiss) and 2 g/L of Na2CO3 at 50 °C for 30 min to remove waxes and impurities, then rinsed thoroughly in cold tap water, and dried at room temperature. The dyeing was carried out in an IR laboratory scale dyeing machine at National Research Centre.
Dyeing process
All dyes were used as pure powder in the same form as prepared without milling. Fabric samples (2 g) were introduced into a flask containing a dyebath of 2% (o.w.f) dye shade and Matexil DA-N (supplied by ICI Company, UK) as dispersing agent at 130 °C with a 1:50 liquor ratio; during dyebath preparation, the dye was
mixed with 10 drops of DMF and then mixed with dispersing agent, and water was added to prepare a homogeneous dispersion of the dye. The pH was adjusted to 4.5 by using acetic acid. At the end of the dyeing process, the dyed samples were removed, rinsed in warm water, and subjected to reduction clearing in a solution comprising 2 g/L of sodium hydrosulphite and 2g/L of sodium hydroxide (caustic soda) for 10 min at 60 °C, with a liquor ratio of 1:40, and the reduction-cleared sample was rinsed thoroughly in water. The dyed samples were removed, rinsed in tap water, and allowed to dry in the open air.
Color Measurements
The colorimetric parameters of the dyed polyester fabrics were determined on areflectance spectrophotometer. The color yields of the dyed samples were determined by using the lightreflectance technique performed on an UltraScan PRO D65 UV/VIS Spectrophotometer. The colorstrengths, expressed as K/S values, were determined by applying the Kubelka-Mink equation 10.
K/S = [(1- R)2 / 2R]- [(1- Ro)2 / 2 Ro]
Where, R is the reflectance of colored samples and K and S are the absorption and scattering coefficients, respectively. Ro = decimal fraction of the reflectance of the undyed fabric.
CIE Lab Difference
ΔE=[ ΔL² + Δa² + Δb² ]½
ΔE: the total color difference between the sample and thestandard: (L) represents the white-black axis, (a) represents the red-green axis and finally (b) represents the yellow-blue axis.
Color Fastness
Color fastness to washing
The color fastness to washing was determined according to the ISO 105-C02:1989 method 12. The composite specimens were sewed between two pieces of bleached cotton and wool fabrics, and then immersed into an aqueous solution containing 5 g/L of nonionic detergents at a liquor ratio of 1:50. The bath was thermostatically adjusted to 60 °C for 30 min. After the desired time, samples were removed, rinsed twice with occasional hand squeezing, and then dried. Evaluation of the wash fastness was established using the grey scale for color change.
Color fastness to rubbing
Color fastness to rubbing was determined according to the ISO 105-X12:1987 test method 13. The test is designed for determining the degree of color that may transfer from the surface of the colored fabrics to another surface by rubbing. The current test can be carried out on dry and wet fabrics.
Dry crocking test
The test specimen was placed flat on the base of the crockmeter. A white testing cloth was mounted. The covered finger was lowered onto the test specimen and caused to slide back and forth 20 times. The white test sample was then removed for evaluation using the grey scale for staining.
Wet crocking test
The white test sample was thoroughly (65%) wetted with water. The procedure was run as before. The white test samples were air dried before evaluation.
Color fastness to perspiration
Two artificial perspiration solutions (acidic and alkaline) were prepared as follows according to the ISO 105-E04:1989 test method 14. The acidic solution was prepared by dissolving L-histidine monohydrochloride monohydrate (0.5 g), sodium chloride (5 g), and sodium dihydrogen orthophosphate dihydrate (2.2 g) in one liter of distilled water. Then, the pH was finally adjusted to 5.5 using 0.1 N NaOH. To prepare the alkaline
solution, L-histidine monohydrochloride monohydrate (0.5 g), sodium chloride (5 g), and disodium hydrogen orthophosphate dihydrate (2.5 g) were all dissolved in one liter of distilled water. The pH was adjusted to 8 using 0.1 N NaOH. The fastness test was performed as follows. The 5 cm × 4 cm colored specimen was sewn between two pieces of uncolored specimens to form a composite specimen. The composite samples were immersed for 15-30 min in both solutions with well agitation and squeezing to ensure complete wetting. The test specimens were placed between two plates of glass or plastic under a force of about 4-5 kg. The plates containing the composite specimens were then held vertically in an oven at 37 ± 2 °C for 4 h. The effect on the color of the tested specimens was expressed and defined by reference to the grey scale for color change.
Color fastness to light
The light fastness test was carried out in accordance with the ISO 105-B02:1988 test method 15, using a carbon arc lamp and continuous light for 35 h. The effect on the color of the tested samples was recorded by reference to the blue scale for color change.
Antimicrobial Activities Test
All prepared disperse dyes were screened in vitro for their antibacterial activities against Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens as Gram negative bacteria and Bacillus cereus , Micrococcus luteus and Staphylococcus aureus as Gram positive bacteria by the agar diffusion technique 16. 1 mg/ml solution in dimethylformamide (DMF) was used. The bacteria are maintained on nutrient agar. DMF showed no inhibition zones. The agar media were inoculated with different microorganism’s culture tested after 24 hours of inoculated at 37 °C for bacteria. The diameter of inhibition zone (mm) was measured. The data obtained is summarized in Table 3 (These tests conducted at Assiut University).
Results and Discussion
Synthesis and Characteristics
Our designed strategy for the synthesis of some azo disperse dyes based on pyrazolopyrimidinone is displayed in Scheme 1. Arylhydrazonopyrazolones 1a-e react with enaminone 2 to yield the corresponding pyrazolo[1,5-a]pyrimidinones disperse dyes 3a-e whose identities were elucidated by using elemental analysis, mass spectral data, 1H-, 13C-NMR spectroscopy as well as the IR, and UV. The possible formation of regioisomers 4a-e in reactions of 1a-e with enaminone 2 is ruled out based not only on 2D NMR experiments 9, but also on X-ray crystallographic structure that performed by one of us for such dyes 10, 11.
Scheme 1: Synthesis of arylazopyrazolopyrimidinones disperse dyes.
Dyeing and Fastness Properties
Arylazopyrazolopyrimidinones dyes 3a-e were applicable for dyeing polyester fabrics as a substrate (2% shade). The obtained data given in Table 1, reveals that the dyeing substrate have diverse K/S and total color difference ΔE. The difference in K/S and ΔE depends on the substitutes existence or its position in the dye molecules 17. The data outlined in Table 1 reveals that the K/S of the dye 3b (29.80) is much higher than the K/S of dyes 3d and 3e (21.90 and 9.41). Also, the total color difference ΔE of dye 3b (93.26) is much higher than the ΔE of dyes 3d and 3e (86.43 and 74.33). We used CIELAB coordinates to express the dyeing color of the substrate as measured: lightness (L); (a) (red–green axis), (b) (yellow-blue axis); chroma (c); hue angle from 0 to 360° (h). Generally, The positive values of (b) = 80.24, 78.36 and 78.85 revealed that the hues of the pyrazolopyrimidinones disperse dyes 3a-c on the substrate moved to the yellowish trend. The hues of the disperse dye 3e on the substrate moved to the greenish trend; this was elucidated by the small value of (a) = 4.20.
Table 1. Optical measurements of azo disperse dyes on the polyester fabrics.
Dye No |
K/S |
λmax |
L |
a |
b |
C |
h |
∆E |
3a |
32.13 |
460 |
61.34 |
22.96 |
80.24 |
83.72 |
74.04 |
92.93 |
3b |
29.80 |
460 |
60.13 |
27.31 |
78.36 |
83.78 |
70.79 |
93.26 |
3c |
26.76 |
445 |
61.56 |
19.71 |
78.85 |
84.22 |
75.97 |
93.28 |
3d |
21.90 |
440 |
65.29 |
12.73 |
65.29 |
77.75 |
80.55 |
86.43 |
3e |
9.41 |
445 |
66.98 |
4.20 |
63.11 |
64.92 |
86.19 |
74.33 |
Fastness Properties
Washing fastness
The washing fastness increase when electron-attracting groups exist in the dye structure, it may be due to these dyes under investigate are clearly diffused into the pores of the substrate and engaged in their positions by a variety of forces as Van der Waal. Electron-withdrawing substituents permit hydrogen bonding and Van der Waal forces with the dyed fabrics consequently, increases their washing fastness, as shown in Table 2.
Rubbing and Perspiration fastness
The obtained data outlined in Table 2 showed that dyed substrate have very good rubbing fastness and excellent perspiration fastness, these results may be attributed to excellent intra-fiber diffusion of the dye molecules inside the substrate and the dye molecule particle size is assumed comparatively enormous.
Light fastness
Several reports demonstrate fading in dyes is a result of disintegration of azo group as photolysis, oxidation, or reduction 18, 19. The rates photolysis, oxidation, or reduction should be sensitive to conditions treatment, the type of substrate and the dyes structure. Since utilized substrate is polyester fabrics, fading probably takes place by oxidation 20. Oxidation of –N=N- linkages supposed to be a component of electron density henceforth; electron attracting groups supposed to decrease the rate of fading, in contrast, electron donating substituent will increase the rate of fading. This is in concurrence with the obtained data that show the existence of NO2 substituent in the dye 3e increases fastness to light to very good (6). Alternatively, the fading is slowly increased for dye 3b to (4), this may be attributed to presence of a CH3 group.
Table 2. Fastness properties of azo disperse dyes on the polyester fabrics.
Dye Number |
Fastness to Rubbing |
Wash fastness |
Fastness to Perspiration |
Fastness to Light |
||||||||
Acidic |
Alkaline |
|||||||||||
Dry |
Wet |
Alt |
SC |
SW |
Alt |
SC |
SW |
Alt |
SC |
SW |
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3a |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
4-5 |
3b |
5 |
5 |
4-5 |
4-5 |
4-5 |
5 |
5 |
5 |
5 |
5 |
5 |
4 |
3c |
5 |
5 |
5 |
5 |
4-5 |
5 |
5 |
5 |
5 |
5 |
5 |
4-5 |
3d |
4-5 |
4-5 |
5 |
5 |
4-5 |
5 |
5 |
5 |
5 |
5 |
5 |
4-5 |
3e |
5 |
5 |
4-5 |
4-5 |
4-5 |
5 |
5 |
5 |
5 |
5 |
5 |
6 |
Where: Alt = Alteration, SC = Staining on cotton, SW = Staining on wool.
Antimicrobial Activity
The obtained results listed in Table 3 showed that dyes 3a and 3e have moderate activities against Escherichia coli and Staphylococcus aureus, respectively. In contrast dyes 3a-e showed no activities against of Serratia marcescens. Disperse dyes 3a and 3d showed positive antimicrobial activities against four microorganisms, while dyes 3b, 3c and 3e showed positive antimicrobial activities against three microorganisms. Hence, the prepared dyes illustrated promising results concerning its possibility to be used in medicinal fields.
Table 3. Antimicrobial activities of the azo disperse dyes.
Dye No |
G- ( inhibition zone in mm ) |
G+ ( inhibition zone in mm ) |
||||
Escherichia coli (cont.26) |
Pseudomonas aeruginosa (cont.42) |
Serratia marcescens (cont.28) |
Bacillus cereus (cont.18) |
Micrococcus luteus (cont.24) |
Staphylococcus aureus (cont.34) |
|
3a |
9 |
8 |
0 |
7 |
0 |
9 |
3b |
7 |
7 |
0 |
0 |
8 |
0 |
3c |
7 |
0 |
0 |
0 |
7 |
8 |
3d |
8 |
8 |
0 |
7 |
0 |
7 |
3e |
10 |
8 |
0 |
0 |
0 |
8 |
Conclusions
A pyrazolopyrimidinones disperse dyes were synthesized. There dyes were applied to polyester fabrics. The dyed substrate displayed excellent perspiration fastness and very good fastness levels to rubbing, light and washing, respectively. Moreover, the antimicrobial activities of these dyes against Gram negative and Gram positive bacteria were discussed.
References
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