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0Arabian Journal of Chemistry (2014) xxx, xxx-xxx
King Saud University Arabian Journal of Chemistry
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ORIGINAL ARTICLE
Synthesis, dyeing performance on polyester fiber and antimicrobial studies of some novel pyrazolotriazine and pyrazolyl pyrazolone azo dyes
Hala F. Rizk, Seham A. Ibrahim *, Mohammed A. El-Borai
Tanta University, Faculty of Science, Chemistry Department, Tanta, Egypt Received 28 April 2013; accepted 16 January 2014
KEYWORDS
Pyrazolotriazine; Pyrazolyl pyrazolone; Disperse dyes; Dyeing parameters; Fastness properties; Antimicrobial activities
Abstract 5-Amino-4-heterylazo-3-phenyl-1H-pyrazoles (2a-d) were diazotized and coupled with malononitrile to give pyrazoloazo malononitrile which by heating in glacial acetic acid gave novel pyrazolo[5,1-c][1,2,4]triazine dyes (3a-d). Also, some diazopyrazolyl pyrazolone dyes (4a-h) were synthesized by diazotization of 2a-d and coupled with some pyrazolone derivatives. The structure of the synthesized dyes was determined by elemental analysis and spectral data. All the synthesized compounds were applied as disperse dyes and their dyeing performance on polyester fabric was studied. The fastness and colorimetric properties were measured. The results revealed that the monoazo dyes have good fastness and good to moderate affinity to polyester fabric than diazo dyes. In addition, the synthesized dyes were screened for their antimicrobial activities against Staphylococcus aureus, Pseudomonas aeruginosa (Gram positive), Bacillus subtitles, Escherichia coli (Gram negative) and Candida albicans, Aspergillus niger (Fungi). The results revealed that most of the prepared dyes have high antibacterial activity.
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1. Introduction
It has been known for many years that the azo compounds are the most widely used class of dyes due to their versatile applications in various fields such as dyeing of textile fibers, coloring of different materials, biological medical studies and
advanced applications in organic synthesis (Bareini 2009; Karipcin et al., 2010). Disperse dyes are very popular and important class for dyeing polyester fibers due to their brilliancy, wide range of hue excellent fastness properties, in addition to the environmental and economic reasons (Metwally et al., 2012). 5-Aminopyrazoles are very important class of het-erocycles due to their biological and pharmacological activities (Tsai and Wang, 2005; Yang et al., 2009). These compounds often exhibit anti-inflammatory, herbicidal, fungicidal, bactericidal, and antipyretic activities (Kumar et al., 2005; Yang et al., 2009; Jung et al., 2002; Gudmundsson et al., 2005; Sung et al., 2011; Gyorgy et al., 2008; Chimichi et al., 2006). The pyrazolotriazine compounds have received much attention owing to their antibacterial, antiviral and antihypertensive
* Corresponding author. Tel.: +20 1009195323. E-mail address: sehamabdelatif@yahoo.com (S.A. Ibrahim). Peer review under responsibility of King Saud University.
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activities. Moreover, they are used as key starting material for the synthesis of commercial arylazopyrazole dyes which have found application in dyes, biological, pharmacological and complexmetric titration (Lister et al., 1970; Ahmed et al., 2012; Menegatti et al., 2006; Tsai and Wang, 2005; Y W Ho 2005; Kandil et al., 2001). As a part of our continuous interest on 5-amino pyrazole derivatives we report here the synthes of some novel azo and disazo dyes having pyrazole moiety and study their applications as disperse dyes to polyester fabrics (M A El-Borai et al. 2011; M A El-Borai et al. 2011; M A El-Borai et al. 2010).
2. Experimental
Commercially available polyester fabrics were used for dyeing. The chemicals used for synthesis were obtained from Sigma-Aldrich and used without further purification, and the solvents were of spectroscopic grade.
2.1. Chemistry
Melting points were recorded on a Gallenkamp melting point apparatus and are reported uncorrected. The infrared spectra were recorded on Perkin-Elmer FTIR 1430 spectrophotometer using KBr disk technique. The NMR spectra were recorded on a Bruker AC spectrometer (300 MHz) at 25 0C in DMSO-d6 with TMS as an internal standard. Chemical shifts are reported in ppm and results are expressed as d values. Mass spectra were measured on a Finnigan MAT 8222 EX mass spectrometer at 70 eV. Ultraviolet-visible (UV-vis) absorption spectra were recorded on an SHIMADZO UV-3101PC spectrophotometer using 1.0 cm matched silica cell. Microanalysis was performed on Perkin-Elmer 2400 Elemental Analyzer at Microanalytical center at Cairo University. Reaction progress was monitored by thin layer chromatography (TLC) using benzene/acetone (2/1 by volume) as eluent. 3-Phenyl-1H-pyra-zol-5-amine 1, 3-methyl-1H-pyrazole-5-one and 3-methyl-1-phenyl-pyrazole-5-one were synthesized according to the previously reported methods (Quiroga et al., 2008; Davies, 1954; Koike et al., 1954).
2.1.1. Dyeing
2.1.1.1. Dyeing procedure. All applications and fastness properties of dye stuffs have been performed at Misr Spinning and Weaving Company, Central Q.C. Laboratories, Mehalla El-Kubra, Egypt. The prepared azo dyes were applied to polyester fiber. The dyeing procedures were carried out according to (M A El-Borai et al. 2009; M A El-Borai et al. 2007).
2.1.1.2. Fastness determination. Color fastness to light, washing, perspiration, and rubbing of the prepared dyes on polyester fabrics were studied using standard methods for the assessment of color fastness of textile (the grey scale) (Anon 1990). The obtained results are recorded in (Table 3).
2.1.1.3. Color measurement. The colorimetric parameters of the dyed polyester fabrics were determined on a reflectance spec-trophotometer (Gretag-Macbeth CE 7000a), equipped with a D65/100 source and barium sulfate as standard blank, and
three repeated measurement average settings. The obtained results are depicted in (Table 4) (See. Table 5).
2.1.1.4. Antimicrobial screening. The microorganisms used in this study included Staphylococcus aureus, Pseudomonas aeruginosa (Gram positive), Bacillus subtitles, Escherichia coli (Gram negative) and Candida albicans, Aspergillus niger (Fungi). The strains under study were obtained from Al Azhar University, Fermentation Biotechnology, and applied Microbiology (Farm-BAM). Bacteria were cultured on nutrient agar and the fungus was cultured on Sabouraud agar slopes. Antimicrobial activities of the synthesized compounds were tested in vitro on nutrient agar at 30 0C after 24 h by the cut-plug method according to Pridham et al. (1965).
2.2. Synthesis
2.2.1. General procedure for the synthesis of 3-phenyl- 5-amino-4-hetarylazopyrazoles (2a-d)
A solution of sodium nitrite (0.651 g, 9.4 mmol) was gradually added to a cold solution (0 0C) of appropriate heterocyclic amines (9.4 mmol) in conc. HCl (8.5%, 3 ml). The diazonium salt obtained was added with continuous stirring to a cold solution (0 0C) of 3-phenyl-1H-pyrazol-5-amine 1 (1.13 g, 6.5 mmol) in ethanol (35 ml) containing sodium acetate (2.5 g). The reaction mixture was stirred at 0 0C for 2 h and the colored solid formed was filtered, washed with water and crystallized from ethanol to give compounds 2a-d.
3-Phenyl-4-(pyrazin-2-yldiazenyl)-1H-pyrazol-5-amine (2a) yield 70%, m.p. 240-242 oC.FTIR (KBr): vmax: 1597(N=N), 3178(NH2) cm"1 NMR[300 MHz,DMSO-d6]: d = 8.20(s, 2H, NH2), 7.10-8.60(m,8H, Ar-H) ppm.Anal. for C13H11N7()-calcd: C, 58.86; H, 4.18; N, 36.96. Found C, 58.26; H, 4.09; N, 36.78%; MS: m/z 265.
4-((1H-Imidazol-2-yl) diazenyl)-3-phenyl-1H-pyrazol-5-amine (2b) yield 69%, m.p. 260-263 oC). FTIR (KBr): vmax: 1578(N=N), 3100(NH2) cm"1 1H NMR[DMSO-d6]: d 9.10(s, 2H, NH2), 11.90(s, 1H, NH of Imidazole ring), 7.20-8.30(m,7H, Ar-H)ppm.Anal. for C12H11N7()calcd: C, 56.91; H, 4.38; N, 38.71.Found C, 56.74; H, 4.21 N, 38.55%; MS: m/z 254.
3-Phenyl-4-(thiazol-2-yldiazenyl)-1H-pyrazol-5-amine (2c) yield 80%, m.p. 250-251 oQ.FTIR (KBr): vmax: 1571(N=N), 3294(NH2) cm"1 1H NMR[300 MHz,DMSO-d6]: d 9.30(s, 2H, NH2), 6.20-8.20(m,7H, Ar-H)ppm. Anal. for C12H10N6S calcd: C, 53.32; H, 3.73; N, 31.09; S, 11.86. Found C, 53.52; H, 3.33; N, 31.04; S, 11.45%; MS: m/z 272.
4-((5-Amino-3-phenyl-1H-pyrazol-4-yl)diazenyl)-2,3-di-methyl-1-phenyl-1,2-dihydropyrazol-5-one (2d) yield 76%, m.p. 230-232 oC.FTIR (KBr): vmax: 1554(N=N), 3159(NH2) cm"1 1H NMR[DMSO-d6]: d 2.10(s, 3H, CH3), 2.40(s, 3H, N-CH3), 8.30(s, 1H, NH2), 7.10-8.20 (m,10H, Ar-H). Anal. for C20H21N7O calcd: C, 64.33; H, 5.13; N, 26.26. Found C, 64.11; H, 5.17; N, 26.26%; MS: m/z 374.
2.2.2. General procedure for the synthesis of 7-amino-6-cyano-2-phenyl-3- substituted azopyrazolo [5, 1-c] [1, 2,4] triazine (3a-d)
Nitrosylsulfuric acid was prepared by dissolving sodium nitrite (1 g) in sulfuric acid (7 ml) at 0 0C. 5-Amino-3-phenyl-4-substi-tuted azo-1H-pyrazole (2a-d) (2 mmol) was dissolved in hot
glacial acetic acid (2.5 ml) and rapidly cooled in ice/salt bath to 0-5 0C. The solution was added in portions over 30 min to nitrosylsulfuric acid at 0-5 0C and the mixture stirred for a further 1 h at this temperature. The resulting diazonium solution was added in portions over 30 min to a vigorously stirred solution of malononitrile (1.32 g, 2 mmol) in pyridine (10 ml), maintaining the pH at 7-8 by addition of solid sodium acetate at 0-5 0C. The mixture was stirred for 2 h at 0-5 0C. The resulting solid was filtered, washed with cold water (3 x 50 mL). A
solution of the precipitated solid in glacial acetic acid (30 ml) was refluxed for 4 h. The solvent was evaporated in vacuo and the remaining product was collected by filtration, dried in air and crystallized from DMF-H2O (3:1) to give compounds 3a-d.
4-Amino-7-phenyl-8-(pyrazin-2-yldiazenyl)pyrazolo[5,1-c][1,2,4]triazine-3-carbonitrile(3a) yield 70%, m.p. 185— 187 0C. FTIR (KBr): vmax: 1554(N=N), 3159 (NH2) cm"1 *H NMR[DMSO-d6]: d 8.40(s, 2H, NH2), 7.10-8.20(m,8H, Ar-H)ppm.Anal. for C16H10N10 calcd: C, 54.54; H, 3.05; N, 42.41. Found C, 54.44; H, 3.14; N, 42.55%;MS: m/z 342.
8-((1H-Imidazol-2-yl)diazenyl)-4-amino-7-phenylpyrazol-o[5,1-c][1,2,4]triazine-3-carbonitrile(3b) yield 69%, m.p. 175— 176 0C.FTIR (KBr): vmax: 1554(N=N),3159(NH2)cm" *H NMR[DMSO-d6]ppm: d 9.47(s, 2H, NH2), 12.50(s, 1H, NH of Imidazole ring), 7.20-8.30(m,7H, Ar-H).Anal. for C15H10N10 calcd: C, 54.54; H, 3.05; N, 42.41. Found C, 54.44; H, 3.14; N, 42.55%; MS: m/z 328.
4-Amino-7-phenyl-8-(thiazol-2-yldiazenyl)pyrazolo[5,1-c] [1,2,4]triazine-3-carbonitrile (3c) yield 80%, m.p. 220221 0C.FTIR (KBr): vmax: 1554(N=N), 3159(NH2) cm"1 *H NMR[DMSO-d6]: d 9.47(s, 2H, NH2), 6.60-8.30(m,7H, Ar-H)ppm.Anal. for C15H9N9S calcd: C, 51.87; H, 2.61; N, 36.29; S, 9.23Found C, 51.23; H, 2.71; N, 36.55; S, 9.43%; MS: m/z 347.
4-((4-Amino-3-methyl-7-phenylpyrazolo[5,1-c][1,2,4]tria-zin-8-yl)diazenyl)-2,3-dimethyl-1-phenyl-1,2-dihydropyrazol-5-one(3d) yield 76%, m.p. 240-242 0C.FTIR (KBr): vmax: 1554(N=N), 3159(NH2) cm"1 *H NMR[DMSO-d6]: d 2.07(s, 3H, CH3), 2.60(s, 3H, N-CH3), 8.40(s, 1H, NH2), 7.40-8.00 (m,10H, Ar-H)ppm.Anal. for C23H18N10O calcd:
Table 1 Absorption spectra of compounds 2a-d, 3a-d and 4a-h.
Cpd. no. Het R Absorption kjnax (nm) Loge
2a Pyrazine ring - 400 4
2b Imidazole ring - 474 3.99
2c Thiazole ring - 404 3.97
2d Antipyrine ring - 400 4.33
3a Pyrazine ring - 463 4.05
3b Imidazole ring - 511 3.99
3c Thiazole ring - 514 4.29
3d Antipyrine ring - 487 4.23
4a Pyrazine ring H 375 4.03
4b Imidazole ring H 406 4.02
4c Thiazole ring H 384 2.98
4d Antipyrine ring H 406 4.38
4e Pyrazine ring Ph 367 4.14
4f Imidazole ring Ph 405 3.03
4g Thiazole ring Ph 382 4.29
4h Antipyrine ring Ph 403 4.33
Table 2 Fastness properties of dyes 2a-d, 3a-d, and 4a-h on polyester fabrica.
Dye. no Colour Washing Perspiration Rubbing Sublimation light
PES Cotton PES Cotton Dry Wet PES Cotton
2a Dark brown 3-4 3 3-4 3-4 3 3 3-4 3-4 4
2b Light brown 3-4 3-4 3-4 3-4 3 3 3 3 4
2c Orange 3-4 3-4 3-4 3-4 3-4 3-4 3-4 3-4 4
2d Brown 3-4 3-4 3-4 3-4 3-4 3-4 3-4 3-4 4
3a Brown 3-4 3-4 3-4 3-4 3-4 3-4 3-4 3-4 5-6
3b Reddish brown 4 4 3-4 3-4 4-5 4 4 4 6
3c Brown 3-4 3-4 3-4 3-4 4-5 4 4 4 6
3d Reddish brown 3-4 3-4 3 3 4-5 4 4 4 6
4a Brown 3-4 3-4 3 3 4-5 4 4 4 6
4b Yellow 3-4 3-4 3-4 3-4 3-4 3-4 3-4 4 6
4c Light brown 3-4 3-4 3 3 4 3-4 3-4 4 6
4d Light brown 3-4 3-4 3 3 3-4 3-4 4 3-4 6
4e Yellow 3-4 3-4 3-4 3-4 3-4 3-4 4 4 6
4f Brown 3-4 3-4 3-4 3-4 3-4 3-4 3-4 4 6
4g Light brown 3-4 3-4 3-4 3-4 3-4 3-4 4 4 5
4h Light -brown 3-4 3-4 3-4 3-4 4 3-4 4 3-4 5
a Rate for light fastness: 4-8 (acceptable), 1-3 (not acceptable); rate for different fastness: 3-4 (acceptable), 1-2 (not acceptable).
Table 3 Color of the dyes 2a-d, 3a-d and 4a-h on polyester
fabrics.
Dye L* a* b* c* % R K/S
2a 47.25 -.5 -0.34 1.22 13.03 2.9
2b 68.16 6.76 26.96 27 14.96 2.4
2c 54.8 31.4 45.03 52.5 3.61 14.83
2d 57.5 7.51 38.9 37.8 4.36 10.48
3a 39.58 18.6 22.55 29.7 3.31 14.12
3b 39.93 7.4 19.15 18.4 3.7 12.53
3c 54.62 31.2 45 55 3.1 14.99
3d 44.24 10.9 27 30 3.09 15.51
4a 84.63 -1.2 18.62 18.2 38.9 0.47
4b 78.1 -8.9 37.89 38.5 15.15 2.37
4c 68.66 6.5 26.6 32.9 15.22 2.36
4d 76.4 11.9 17.74 45 29.8 0.82
4e 80.77 -0.6 34.38 40 21 1.48
4f 57.4 7.47 39.19 14.9 4.3 10.64
4g 69 6.39 26.7 27.5 14 12.5
4h 69.1 24.5 23.89 34 18.57 1.78
C, 61.93; H, 4.55; N, 30.09. Found C, 61.77; H, 4.74; N, 30.11%; MS: m/z 450.
2.2.3. General procedure for the synthesis of 5-(3/-phenyl-4/-hetarylazo-1/H-pyrazol-5/-ylazo-3-methyl-5-hydroxy-pyrazole (4ah)
5-Amino-3-phenyl-4-(substituted hetarylazo)-1H-pyrazole (2a-d) (2 mmol) was dissolved in hot glacial acetic acid (2.5 ml) and rapidly cooled in an ice-salt bath at 0-5 0C. The solution was then added in portions over 30 min to nitrosyl sulfuric acid at 0-5 0C and the mixture was stirred for a further 1 h at this temperature. The resulting diazonium solution was added in portions over 30 min to a vigorously stirred solution of 3-methyl-1H-pyrazole-5-one (0.196 g, 2 mmol) and/or
3-methyl-1-phenyl-pyrazole-5-one (0.348 g, 2 mmol) in potassium hydroxide (0.11 g, 2 mmol) and water (2 ml) at 0-5 0C. The pH of the coupling mixture was maintained at 5-6 by adding solid sodium acetate. The mixture was stirred for 1 h at 0-5 0C; the resulting solid was filtered, washed with cold water (3 x 30 mL) and dried in air, crystallized from DMF/ H2O (1:1) mixture to give compounds 4a-h.
3-Phenyl-4-(pyrazin-2-ylazo)-5-(3-methyl-1-H-5-pyrazolon-
4-ylazo)-1H-pyrazole(4a) yield 60%, m.p. 130-131 0C.FTIR (KBr): vmax: 1518(N=N),1670(C=0), 3327(NH) cm"1 1H NMR[DMS0-d6]: d 2.40(s,3H,CH3),7.17(s,1H,CH), 10.54 (s,1H,NH of pyrazole ring), 11.70(s,1H, NH of pyrazolone ring),12.50(s,1H,0H or NH), 7.48-8.45(m,7H, Ar-H)ppm. Anal. for C20H17N502 calcd: C, 54.54; H, 3.77; N, 37.42. Found C, 54.56; H, 3.97; N, 37.48%; MS: m/z 374.
3-Phenyl-4-(1H-imidazol-2-ylazo)-5-(3-methyl-1H-5-pyraz-olon-4-ylazo)-1H-pyrazole (4b) yield 45%, m.p. 200-202 0C. FTIR (KBr): vmax: 1633(N=N) and 1711(C=0), 3413 (NH)cm"1. 1H NMR[DMS0-d6]: d 2.07(s,3H,CH3), 6.60(s,1H,CH), 11.05 (s,1H, NH of imidazole ring), 11.20 (s,1H, NH of pyrazole ring), 12.10(s,1H, NH of pyrazolone ring), 12.50(s,1H,0H or NH), 6.90-8.80(m,7H, Ar-H)ppm Anal. for C16H14N100 calcd: C, 53.03; H, 3.89; N, 38.66. Found C, 53.11; H, 3.79; N, 38.86%; MS: m/z 362.
3-Phenyl-4-(1,3-thiazol-2-ylazo)-5-(3-methyl-1H-5-pyrazo-lon-4-ylazo)-1H-pyrazole (4c) yield 45%, m.p. 200202 0C.FTIR (KBr): vmax: 1573(N=N),1691(C=0), 3396(NH)cm"1.1H NMR[DMS0-d6]: d 2.30(s,3H,CH3),6.90(-s,1H,CH),10.70(s,1H,NH of pyrazole ring),11.70(s,1H, NH of pyrazolone ring),12.50(s,1H,0H or NH),7.40-8.20(m,7H, Ar-H)ppm. Anal. for C16H13N90S calcd: C, 50.65; H, 3.45; N, 33.23; S, 8.45. Found C, 50.78; H, 3.45; N, 33.77; S, 8.35%; MS: m/z 380.
3-Phenyl-4-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-yla-zo)-5-(3-methyl-1H-5-pyrazolon-4-ylazo)-1H-pyrazole(4d) yield: 50%, m.p. 170-172 0C. FTIR (KBr): vmax: 1638 (N=N),
Table 4 Diameters of inhibition zones (mm) of newly synthesized compounds against different test bacteria and fungi on nutrient agar at 300C after 24 hb.
Compound Bacillus subtilis E.coli Staphylococcus aureus Pseudomona saeruginosa Candida albicans A.nigar
2a -ve - ve 13 12 15 -ve
2b -ve - ve -ve -ve 14 -ve
2c 24 27 26 25 26.5
2d - ve - ve -ve -ve -ve -ve
3a 42 20 21 21.5 21 15
3b 20.5 20 21 20.5 22 18
3c 16 21.5 16 16.5 17 -ve
3d 17 19 15 18 15.5 -ve
4a 18 21 20 17 20 -ve
4b 16 16 18 16.5 17 -ve
4c 15.5 17 19 18 18 -ve
4d - ve - ve -ve -ve -ve -ve
4e - ve - ve -ve -ve -ve -ve
4f 17.5 24 - 16 15.5 -ve
4g 20 24 21 22 23.5 -ve
4h 19 22 19 21 20 -ve
St 31.5 30 32 37.5 25 23
St = Standard Miphinicol was used at conc.1 mg/ml for gram positive bacteria, while Keflex was used as standard for gram negative bacteria at conc 1 mg/ml. Flucoral was used as standard for fungi at conc. 1 mg/ml. Amikacin was tested as standard at conc 1 mg/ml for Candida albicans.
b The concentration used is 10mg/mL. Control disks were performed in DMSO (dimethylsulfoxide) and no zones of inhibitions were observed. -ve = resistant.
Table 5 Minimal inhibitory concentration (MIC) of the provided samples against test microorganisms (MIC) lg/ml.
Compound Bacillus subtilis E.coli Staphylococcus aureus Pseudomonasaeruginosa Candida albicans A.nigar
3a 62.5 125 125 62.5 62.5 1000
3b 125 62.5 31.25 62.5 62.5 1000
St 31.25 62.5 31.25 62.5 31.25 1000
All the dilutions of both samples and standards were performed by double fold dilution.
1657 (C=O), 3425(NH) cm"1. NMR[DMSO-d6]: d 2.07(s,3H,CH3),2.16(s,3H,CH3),2.60(s,3H,N-CH3), 6.90(s,1H, CH),10.50 (s,1H,NH of pyrazole ring),11.70(s,1H, NH of pyrazolone ring),12.80(s,1H,OH or NH),7.39-8.25 (m,10H, Ar-H)ppm. Anal. for C24H22N10O2 calcd: C, 59.74; H, 4.60; N, 29.03. Found C, 59.88; H, 4.59; N, 29.03%; MS: m/z 483.
3-Phenyl-4-(pyrazin-2-ylazo)-5-(3-methyl-1-phenyl-5-pyraz-olon-4-ylazo)-1H-pyrazole (4e) yield 54%, m.p. 205-207 oc. FTIR (KBr): vmax: 1633(N=N),1700(C=O),3425(NH)cm"1. :HNMR[DMSO-d6]: d 2.37(s,3H,CH3),6.90(s,1H,CH),13.55 (s,1H,NH of pyrazole ring), 14.54 (s,1H,OH or NH), 7.068.6 (m,12H, Ar-H) ppm. Anal.calcd for C23H18N10O: C, 61.33; H, 4.03; N, 31.09.Found C, 61.33; H, 4.10; N, 31.27%; MS: m/z 450.
3-Phenyl-4-(1H-imidazol-2-ylazo)-5-(3-methyl-1phenyl-5-pyrazolon-4-ylazo)-1H-pyrazole (4f) yield 54%; m.p. 205-207 o C.FTIR (KBr): vmax: 1637(N=N),1699(C=O), 3434(NH) cm"1 *H NMR[DMSO-d6]: d 2.37(s,3H,CH3),7.2(s,1H,CH),
13.5(s,1H,NH of imidazole ring),14(s,1H, NH of pyrazole ring),14.5(s,1H,OH or NH), 7.7-8.2 (m,12H, Ar-H)ppm. Anal. for C22H18N10O calcd: C, 60.27; H, 4.14; N, 31.95. Found C, 59.99; H, 4.19; N, 31.78%; MS: m/z 438.
3-Phenyl-4-(1,3-thiazol-2-ylazo)-5-(3-methyl-1phenyl-5-pyrazolon-4-ylazo)-1H-pyrazole (4g) yield 59%, m.p. 225-227 0C.FTIR (KBr): vmax: 1539(N=N),1627(C=O),3326 (NH)cm~uH NMR[DMSO-d6]: d 2.30(s,3H,CH3), 6.60(s,1H, CH),12.80(s,1H,NH of pyrazole ring), 13.50(s,1H,OH or NH), 6.90-8.60(m,12H, Ar-H)ppm. Anal. for C22H17N9OS calcd: C, 58.01; H, 3.76; N, 27.68; S, 7.04.Found C, 58.11; H, 3.76; N, 27.96; S, 7.11%; MS: m/z 455.
3-Phenyl-4-(2,3-dimethyl-1-phenyl-3-pyrazolin-5-one-4-yla-zo)-5-(3-methyl-1phenyl-5-pyrazolon-4-ylazo)-1H-pyrazole (4h) yield 60%, m.p. 260-261 0C.FTIR (KBr): vmax: 1583(N=N),1649(C=O), 3421(NH)cm~1 NMR[DMSO-d6]: d 2.30(s,3H,CH3),2.37(s,3H,CH3),2.60(s,3H,N-CH3), 7.00 (s,1H,CH),13.59 (s,1H,NH of pyrazole ring), 13.70(s,1H,OH
NH: NH
Het—N=N
N ® e „
Het-4N2Cl Д
\ (i) AcOH \ H2SO4 NaNO2
.NH -:—»
N' (ii)CH2(CN)2\ pyridra
(i) AcOH \ H2SO4NaNO2 R
Het-N=N-T=
N-----/ XN
\\ i CN
AcOH heat
O^ ^N.
Het—N=N I-/
Het-N=N N-N=*—
Het—N=N /-\ N=N
Л- .NH N
T1 (azo-hydrazo-keto)
Het~N=N i—\ N=N-^JL„l, .NH CH3
B (azo-enamine)
A (hydrazo-imine)
T2 (disazo-enol)
Scheme 1
or NH), 7.20-8.60 (m,15H, Ar-H)ppm. Anal. for C30H26N1002 calcd: C, 58.01; H, 3.76; N, 27.68.
Found C, 58.17 H, 3.55; N, 27.97%; MS: m/z 559.
3. Results and discussion
We report here the synthesis of a series of monoazo dyes based on pyrazolo[5,1-c][1,2,4] triazine (3a-d) by coupling of 5-ami-no-3-phenyl-1H-pyrazole 1 with a variety of heterocyclic dia-zonium salts to give the corresponding 3-phenyl-5-amino-4-heteroazo-1H-pyrazoles (2a-d) in good yield (Scheme 1). The IR spectra of compound (2a-d) showed the characteristic absorption bands at y1554-1597 cm"1 for the azo group and at c 3378-3427 cm"1 for the amino group at position 5. The diazotization of 2a-d was followed by coupling with malono-nitrile in pyridine at pH 7-8, the formed solid was filtered quickly and refluxed in glacial acetic acid to give compounds 3a-d (Scheme 1). Azo dyes 3a-d can exist in two possible tautomeric forms, namely the azo-enamine form A and the hydra-zo-imine form B as shown in (Scheme 1). The IR spectra of compounds 3a-d showed the characteristic absorption band group at c 2207-2216 cm"1 for the Cyano group, at c 15831587 cm"1 for the azo group and a broad band at 3159 cm"1 for the amino group. Furthermore, the 1H NMR spectra of compounds 3a-d showed the presence a singlet attributed to amino protons at d 8.40-9.47 ppm and multiplet at d 7.058.30 ppm corresponding to heteroaromatic moieties, which confirm the azo-enamine form B for these compounds. The heterocyclic diazo pyrazolone dyes (4a-h) were prepared by coupling 3-phenyl-1H-pyrazole-5-one and 1, 3-diphenyl-pyra-zole-5-one with diazotized 5-amino-3-phenyl-4-hetarylazo-1H-pyrazoles (Scheme 1). The 1H NMR spectra of dyes 4a-h showed a singlet at d 2.07-2.40 ppm (CH3 of pyrazolone ring), a broad peak at d 12.5-14.5 ppm for -0H or -NH protons (enol or hydrazo forms of pyrazolone ring), a broad peak at d 11.7-14.00 ppm for -NH protons (1-H of pyrazolone ring) and a broad peak at d 10.54-11.20 ppm for -NH protons (1-H of pyrazole ring). The obtained results revealed that the prepared dyes are in favor of the predominantly single tautomeric form (T1 or T2 as shown in scheme 1), the mass spectral data confirm the structure of all the synthesized compounds (see. Experimental).
4. UV-vis spectroscopic analysis of dyes 2a-d, 3a-d, and 4a-h
It is well known that heterocyclic based azo disperse dyes tend to gave a pronounced bathochromic shift compared to the corresponding benzenoid compounds (Hallas and Choi, 1999; Joerg et al., 1988), with larger solvatochromic effects due to the increasing polarity of the dye system, especially in the excited state.
The electronic spectra showed kmax at 400-474 nm for dyes 2a-d, and kmax 463-514 nm for the prepared dyes 2a-d, and 3a-d respectively (Table 1). These bands were due to electronic transitions involving the whole conjugate system (both of the phenyl rings, heterocyclic moieties and the azo group which assigned to a transition of p-p* type).The introduction of the cyano group as an electron withdrawing subsistent onto compounds 3a-d produces a bathochromic shift of the absorption band. This is attributed to more extensive electron delo-calization and small steric requirements of the rod-like cyano
group (Hiremith et al., 2002), the obtained results are depicted in (Table 1).
The electronic spectra of the compounds 4a-h showed a band at kmax 375-406 nm due to the p-p*excitation of the electrons of the azo groups. It is worthy to note that the absor-bance bands for biazopyrazolyl pyrazolone dyes 4a-h located in the region kmax 375-406 nm are due to deformation of the functional groups.
5. The dyeing properties of the prepared dyes on polyester fabrics
The results obtained are depicted in (Table 2), having the following observations:
(a) The dyed fabrics 3b, 3c, 3d, 4a exhibit excellent (4-5) washing, perspiration, sublimation and rubbing fastness properties, while dyes 2a-d, 3a, 4b-h exhibit good (3-4) washing, perspiration, sublimation and rubbing fastness properties.
(b) The light fastness of dyed fabrics exhibit moderate to very good (5-6) fastness properties for all the synthesized dyes.
6. Color assessment
The assessment of color-dyed fabrics was made in terms of tri-stimulus colorimetry. The following CIELAB coordinates are measured, lightness (L*), chroma (c*), hue angle from 0 0C to 360 0C (h), (a*) value represents the degree of redness (positive) and greenness (negative) and (b*) represents the degree of yellowness (positive) and blueness (negative). The measured K/S values given by the reflectance spectrometer are directly correlated with the dye concentration on the dye substrate according to the KubelkaeMunk equation: K/S = (1—R)2/ 2R. Where K = absorbance coefficient, S = scattering coefficient, R = reflectance ratio. The color coordinates indicate that the dyes have good affinity to polyester fabrics with the following conclusions (Table 3):
(a) The color hues of the dyes under investigation on polyester fabric are shifted to the yellowish direction on the yellow-blue axis according to the positive values of b*, while the color hues of the 2a (—0.49) are shifted to the bluish direction on the yellow-blue axis as according to the negative values of b* for these dyes.
(b) The color hue of the dye 2a, 4a, 4b on polyester fabric is shifted to the greenish direction on the red green axis as indicated from the negative value of a* (—1.11, —1.62, —8.97 respectively), while the color hues of the other synthesized dyes on polyester fabrics are shifted to the reddish direction on the red green axis as according to the positive values of a* for the prepared dyes.
(c) The 2b, 4a-e, 4e, 4h, 4g, dyes are more light than the corresponding dyes 2a, 2c, 2d, 4a-d, 5f according to the color lightness values (L*).
(d) The 2c, d, 3c, 4b, e, f, h dyes are brighter than the corresponding dyes 2a, b, 3a, b, d, 4a, c, d, g according to the color brightness value (C*).
(e) K/S values in the dyes under investigation 2a-d, 3a-d and 4a-h vary from 0.47 to 15.51. Dyes 2a, c and 3a-d are characterized by higher K/S values compared with the other dyes, indicating that the color strength on polyester fabrics increases at high temperature and gave generally deep and bright intense hues, ranging from yellow to reddish brown, while dyes 4a-h showed less affinity due to large and asymmetric structure of the dyes which prevent the substantivity of dyes on fiber.
7. Antimicrobial activity
The antibacterial and anti-fungal activities of the dyes were determined against four bacteria S. aureus, P. aeruginosa (Gram positive), B. subtitles, E. coli (Gram negative) and C. albicans, A. niger (fungi). Results of the antimicrobial tests are presented in (Table 4). All the tested compounds except 2a, 2b, 2d, 4d, 4e exhibited strong activity against all strains of tested organisms. For antifungal activity among the compounds tested only compounds 3a, 3b were active against the A. niger fungi. On the other hand 2d, 4d, 4e exhibited inactivity against C. albicans.
8. Conclusions
In this work, a series of new monoazo dyes based on pyrazolo [5, 1-c] [1, 2, 4] triazine ring 3a-d, the heterocyclic series of dis-azo pyrazolone dyes 4a-h have been synthesized. The characterization and the absorption ability of novel disperse dyes 3a-d, 4a-h were studied. All the synthesized compounds were applied to polyester fabrics as disperse dyes. The fastness and colorimetric properties were measured. The results revealed that the monoazo dyes have good fastness and good to moderate affinity to polyester fiber than diazo dyes and also significant antimicrobial activity, the results revealed that all compounds except 2a, 2b, 2d, 4d, 4e compounds exhibited antibacterial activity of high order against all strains of the bacteria used. For antifungal activity the tested compounds except 2d, 4d, 4e exhibited activity against C. albicans while only compounds 3a, 3b were active against A. niger fungi.
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