untitled European Journal of Chemistry 5 (4) (2014) 639‐643 European Journal of Chemistry ISSN 2153‐2249 (Print) / ISSN 2153‐2257 (Online)  2014 Eurjchem Publishing ‐ Printed in the USA http://dx.doi.org/10.5155/eurjchem.5.4.639‐643.1126 European Journal of Chemistry Journal homepage: www.eurjchem.com Pyridazine derivatives and its related compounds. Part 31. Synthesis of some disperse dyes derived from 3‐amino‐1H‐pyrzolo[3,4‐c]pyridazine and their color assessment on polyester fabrics Ali AbdelHamid Deeb a,*, Mamdoh Bahgat El‐Hossami b and Ahmed Awad AbdelGawad c,d a Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt b Printing, Dyeing and Finishing Department, Faculty of Applied Arts, Helwan University, Giza, 12311, Egypt c Medicinal and Aromatic Plants Department, Desert Research Center, Cairo, 11753, Egypt d Department of Chemistry, Faculty of Science, Jazan University, Jizan, 2097, Saudi Arabia *Corresponding author at: Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt. Tel.: +20.55.2303252. Fax: +20.55.2308213. E‐mail address: dralideeb@hotmail.com (A.A. Deeb). ARTICLE INFORMATION ABSTRACT DOI: 10.5155/eurjchem.5.4.639‐643.1126 Received: 21 July 2014 Received in revised form: 23 August 2014 Accepted: 23 August 2014 Online: 31 December 2014 KEYWORDS The 6‐methyl‐3, 4‐diphenyl‐7‐(2‐phenylhydrazono) pyrimido [1', 2':1, 5] pyrazolo [3,4‐c] pyridazin‐8(7H)‐one and 3,4‐diphenyl‐7‐(phenyldiazenyl)pyrimido[1',2':1,5]pyrazolo[3,4‐ c]pyridazine‐6,8‐diamine derivatives were applied to polyester fiber as disperse dyes. They were found to exhibit varying in hue from orange‐yellow to orange‐red, their absorption spectral characteristics, fastness properties and colour assessment are also reported. Color assessment Dyeing properties Fastness properties Heterarylazo disperse dyes Absorption spectral characteristics 3‐Amino‐1H‐pyrazolo[3,4‐c]pyridazine 1. Introduction Azo disperse dyes derived from heterocyclic ring systems have many advantages, such as color deepening effect as an intrinsic property of heterocyclic ring and resulting in good sublimation fastness of dyes fibers [1]. For instance, amino‐ subtituted pyrazole, thiazole, thiophene compounds afforded very electronegative diazo components and, consequently, provide a pronounced benzenenoid compounds [2]. We have previously reported the synthesis of novel heterocyclic systems such as 3‐substituted azo‐3H‐pyrazolo[3,4‐c]pyridazines [3], 4‐[(4‐arylazo‐3,5‐dimethylpyrazol‐1‐yl)carbonyl]‐3,6‐diphenyl pyridazine‐3(2H)‐one (Part 30) [4], 3‐(4‐arylazo‐3,5‐disubsti‐ tuted pyrazol‐1‐yl)‐4,5,6‐triphenylpyridazines [5] and 5‐ amino‐6‐[[4‐arylazo‐3,5‐dimethylpyrazol‐1‐yl]‐carbonyl]‐3,4‐ diphenylthieno[2,3‐c]pyridazines [6] and their application to polyester fibers as disperse dyes, which gave encouraging results. In continuation of our studies, we report here the synthesis of 6‐methyl‐3,4‐diphenyl‐7‐(2‐phenylhydrazono)pyrimido [1', 2':1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one and 3,4‐diphenyl‐7‐ (phenyldiazenyl)pyrimido[1',2':1,5]pyrazolo[3,4‐c]pyridazine‐ 6,8‐diamine derivatives use as disperse dyes for polyester. The absorption spectral characteristics, fastness properties and color assessment of the dyes are also discussed. 2. Experimental 2.1. Instrumentation All melting points were measured using a Büchi 510 melting point apparatus and are reported uncorrected. IR spectra were recorded on a Bruker Vector 22 Germany spectro‐ meter (KBr). The 1H NMR spectra were obtained on Varian Gemini 200MHz spectrometer, and chemical shifts are expressed in δ ppm using TMS as an internal standard. Mass spectra were obtained at 70eV using a GCMS‐QP1000EX Shimadzu spectrometer. Electronic spectra were recorded on UV‐visible recording Shimadzu spectrophotometer from dye solution in DMF at a concentration of 1×10‐5mole/L. 2.2. Synthesis The synthesis of 3‐amino‐4,5‐diphenyl‐1H‐pyrazolo[3,4‐ c]pyridazine 2 (Scheme 1) [7], and azobenzene compounds 640 Deeb et al. / European Journal of Chemistry 5 (4) (2014) 639‐643 Scheme 1 Scheme 2 Scheme 3 3a‐e and 4a‐i [8], were conducted according to known procedures. Spectral data for compounds 3a‐e and 4a‐i were described in the previous parts (Scheme 2 and 3) [9,10]. 2.2.1.General procedure for the synthesis of 6‐methyl‐3,4‐ diphenyl‐7‐(2‐phenylhydrazono)pyrimido [1',2':1,5] pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5a‐e) To a solution of 3‐amino‐4,5‐diphenyl‐1H‐pyrazolo[3,4‐ c]pyridazine 2 (1.0 g, 3.48 mmoles) in a mixture of ethanol and pyridine 20 mL (3:1, v:v), ethyl azobenzeneacetoacetate derivatives 3a‐e (3.48 mmoles) were added, the reaction mixture was refluxed for specific reaction time. The solvent was reduced to its half and left at room temperature for 48 h. The separated solid was filtered off, washed with ethanol (80%), dried and recrystallized from ethanol (Scheme 2) . 6‐Methyl‐3,4‐diphenyl‐7‐(2‐phenylhydrazono)pyrimido [1',2': 1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5a): Prepared from ethyl phenylazoacetoacetate 3a. Reaction time: 8 h. Color: Yellow crystals. Yield: 69%. M.p.: 232‐233 °C. FT‐IR (KBr, ν, cm‐ 1): 3446, 3176 (NH), 3073(CHarom.), 2918 (CHaliph.), 1671 (C=O), 1600 (C=N), 1546(C=C). UV/Vis (DMF, λmax, nm, (log )): 267.4 (4.1). Anal. calcd. for C27H19N7O: C, 70.88; H, 4.19; N, 21.43. Found: C, 70.70; H, 4.00; N, 21.40%. 6‐Methyl‐3,4‐diphenyl‐7‐(2‐(p‐tolyl)hydrazono)pyrimido [1', 2':1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5b): Prepared from ethyl 4‐methylphenylazoacetoacetate 3b. Reaction time: 10 h. Color: Yellow crystals. Yield: 73%. M.p.: 234‐235 °C. FT‐IR (KBr, ν, cm‐1): 3454, 3157 (NH), 3077 (CHarom.), 2915, 2860 (CHaliph.), 1671 (C=O), 1557 (C=C). UV/Vis (DMF, λmax, nm, (log )): 266.5 (4.3). Anal. calcd. for C28H21N7O: C, 71.32; H, 4.49; N, 20.79. Found: C, 71.20; H, 4.30; N, 20.75%. 7‐(2‐(4‐Methoxyphenyl)hydrazono)‐6‐methyl‐3, 4‐diphenyl pyrimido[1',2':1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5c): Pre‐ pared from ethyl 4‐methoxyphenylazoacetoacetate 3c. Reaction time: 7 h. Color: Yellow crystals. Yield: 83%. M.p.: 248‐ 249 °C. FT‐IR (KBr, ν, cm‐1): 3441 (NH), 3056 (CHarom.), 2923 (CHaliph.), 2838 (OCH3), 1597 (C=N), 1539 (C=C). MS (EI, m/z (%)): 488 (M++1, 3.88), 487 (M+, 7.70), 353 (0.55), 108 (100). UV/Vis (DMF, λmax, nm, (log )): 275.7 (4.0). Anal. calcd. for C28H21N7O2: C, 68.98; H, 4.34; N, 20.11. Found: C, 68.80; H, 4.20; N, 20.10%. 7‐(2‐(2‐Chlorophenyl)hydrazono)‐6‐methyl‐3, 4‐diphenylpyri mido[1',2':1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5d): Prepa‐ red from ethyl 2‐chlorophenylazoacetoacetate 3d. Reaction time: 7 h. Color: Yellow crystals. Yield: 78%. M.p.: 245‐246 °C. FT‐IR (KBr, ν, cm‐1): 3188 (NH), 3032 (CHarom.), 2924 (CHaliph.), 1666 (C=O), 1546 (C=C), 756 (Cl‐C). MS (EI, m/z (%)):494 (M++2, 0.57), 492(M+, 0.42), 383 (2.89), 339 (10.58). UV/Vis (DMF, λmax, nm, (log )): 265.2 (4.0). Anal. calcd. for C27H18ClN7O: C, 65.92; H, 3.69; N, 19.93. Found: C, 65.90; H, 3.50; N, 19.90%. 6‐Methyl‐7‐(2‐(4‐nitrophenyl)hydrazono)‐3, 4‐diphenylpyri‐ mido[1',2':1,5]pyrazolo[3,4‐c]pyridazin‐8(7H)‐one (5e): Prepa‐ red from ethyl 4‐nitrophenylazoacetoacetate 3e. Reaction time: 6 h. Color: Yellow crystals. Yield: 79.6%. M.p.: 242‐243 °C. FT‐IR (KBr, ν, cm‐1): 3421, 3188 (NH), 3082 (CHarom.), 2931 (CHaliph.), 1719 (C=O), 1611 (C=N), 1554 (C=C), 1517, 1338 (NO2). MS (EI, m/z (%)): 501 (M+‐1, 14.7), 500 (M+‐2, 50.5), 123 (100). UV/Vis (DMF, λmax, nm, (log )): 265 (4.2). Anal. calcd. for C27H18N8O3: C, 64.54; H, 3.61; N, 22.30. Found: C, 64.30; H, 3.40; N, 20.30%. 2.2.2. General procedure for the synthesis of 3,4‐diphenyl‐7‐ (phenyldiazenyl)pyrimido[1',2':1,5]pyrazolo[3,4‐c] pyridazine‐6,8‐diamine (6a‐i) To a solution of 3‐amino‐4,5‐diphenyl‐1H‐pyrazolo[3,4‐ c]pyridazine 2 (1.0 g, 3.48 mmoles) in a mixture of ethanol and pyridine 30 mL (3:1, v:v), azobenzene malononitrile derivatives 4a‐i (3.48 mmoles) was added, the reaction mixture was refluxed for specific time. The solvent was reduced and left at room temperature. The separated solid was filtered off, washed Deeb et al. / European Journal of Chemistry 5 (4) (2014) 639‐643 641 with ethanol (80%), dried and recrystallized from ethanol (Scheme 3). 3,4‐Diphenyl‐7‐(phenyldiazenyl)pyrimido[1',2':1,5] pyrazolo [3,4‐c]pyridazine‐6,8‐diamine (6a): Prepared from phenylazo malononitrile 4a. Reaction time: 18 h. Color: Yellow crystals. Yield: 62.5%. M.p.: 281‐282 °C. FT‐IR (KBr, ν, cm‐1):3444, 3378, 3324, 3151 (NH2 groups), 3059 (CHarom.), 2911 (CHaliph.), 1613 (C=N), 1565 (C=C). UV/Vis (DMF, λmax, nm, (log )):269.9(4.4). Anal. calcd. for C26H19N9: C, 68.26; H, 4.19; N, 27.55. Found: C, 68.10; H, 4.00; N, 27.60%. 3,4‐Diphenyl‐7‐(p‐tolyldiazenyl)pyrimido[1',2':1,5] pyrazolo [3,4‐c]pyridazine‐6,8‐diamine (6b): Prepared from 4‐methyl phenylazomalononitrile 4b. Reaction time: 24 h. Color: Yellow crystals. Yield: 61%. M.p.: > 300 °C. FT‐IR (KBr, ν, cm‐1):3467, 3399, 3275, 3128 (NH2 groups), 2919, 2854 (CHaliph.), 1609(C=N). MS (EI, m/z (%)):472 (M+, 0.63), 119 (2.62), 91 (5.51). UV/Vis (DMF, λmax, nm, (log )): 265.4 (4.6). Anal. calcd. for C27H21N9: C, 68.78; H, 4.49; N, 26.74. Found: C, 68.60; H, 4.30; N, 26.80%. 7‐((4‐Methoxyphenyl)diazenyl)‐3,4‐diphenylpyrimido [1',2': 1,5]pyrazolo[3,4‐c]pyridazine‐6,8‐diamine (6c): Prepared from 4‐methoxyphenylazomalononitrile 4c. Reaction time: 24 h. Color: brown crystals. Yield: 70%. M.p.: 298‐299 °C. FT‐IR (KBr, ν, cm‐1):3455, 3407, 3262, 3122 (NH2 groups), 2938 (CHaliph.), 2834 (OCH3), 1598 (C=N), 1545 (C=C). UV/Vis (DMF, λmax, nm, (log )): 265.8 (4.1). Anal. calcd. for C27H21N9O (487.52): C, 66.52; H, 4.34; N, 25.86. Found: C, 66.40; H, 4.20; N, 25.80%. 7‐((2‐Chlorophenyl)diazenyl)‐3,4‐diphenylpyrimido[1',2':1,5] pyrazolo[3,4‐c]pyridazine‐6,8‐diamine (6d): Prepared from 2‐ chlorophenylazomalononitrile 4d. Reaction time: 14 h. Color: yellow crystals. Yield: 81.4%. M.p.: > 300 °C. FT‐IR (KBr, ν, cm‐ 1):3466, 3389, 3270, 3139 (NH2 groups), 3069 (CHarom.), 2938 (CHaliph), 1610 (C=N), 1544 (C=C), 751 (C‐Cl). MS (EI, m/z (%)):494.4 (M+ + 2, 0.2), 440 (100), 414 (2.32), 380 (1.05), 337 (0.19), 352 (0.77). Anal. calcd. for C26H18ClN9 (491.94): C, 63.48; H, 3.69; N, 25.63. Found: C, 63.30; H, 3.50; N, 25.60%. 7‐((4‐Nitrophenyl)diazenyl)‐3,4‐diphenylpyrimido[1',2':1, 5] pyrazolo[3,4‐c]pyridazine‐6,8‐diamine (6e): Prepared from 4‐ nitrophenylazomalononitrile 4e. Reaction time: 24 h. Color: Red crystals. Yield: 68.2%. M.p.: > 300 °C. FT‐IR (KBr, ν, cm‐1): 3450, 3338, 3273 (NH2 groups), 1609 (C=N), 1579 (C=C), 1508, 1318 (NO2). MS (EI, m/z (%)):503 (M+, 25.45), 381 (3.44), 353 (6.06), 77 (100). UV/Vis (DMF, λmax, nm, (log )): 266 (4.5). Anal. calcd. For C26H18N10O2: C, 62.15; H, 3.61; N, 27.87. Found: C, 62.00; H, 3.50; N, 27.80%. 3,4‐Diphenyl‐7‐(o‐tolyldiazenyl)pyrimido[1',2':1, 5]pyrazolo [3,4‐c]pyridazine‐6,8‐diamine (6f): Prepared from 2‐methyl phenylazomalononitrile 4f. Reaction time: 24 h. Color: Yellow crystals. Yield: 67%. M.p.: 288‐289 °C. FT‐IR (KBr, ν, cm‐1): 3435, 3395, 3268, 3135 (NH2 groups), 2915 (CHaliph.), 1604 (C=N), 1517 (C=C). UV/Vis (DMF, λmax, nm, (log )): 266.1 (4.1). Anal. calcd. for C27H21N9: C, 68.78; H, 4.49; N, 26.74. Found: C, 68.60; H, 4.30; N, 26.65%. 3,4‐Diphenyl‐7‐(m‐tolyldiazenyl)pyrimido[1',2':1, 5]pyrazolo [3,4‐c]pyridazine‐6,8‐diamine (6g): Prepared from 3‐methyl phenylazomalononitrile 4g. Reaction time: 24 h. Color: Yellow crystals. Yield: 61%. M.p.: 283‐284 °C. FT‐IR (KBr, ν, cm‐1): 3408, 3375, 3264, 3116 (NH2 groups), 2918, 2853 (CHaliph.), 1602 (C=N). MS (EI, m/z (%)): 396 (0.14), 382 (0.23), 354 (0.57), 319 (0.24), 91 (100). Anal. calcd. forC27H21N9: C, 68.78; H, 4.49; N, 26.74. Found: C, 68.70; H, 4.50; N, 26.70%. 7‐((2‐Methoxyphenyl)diazenyl)‐3,4‐diphenylpyrimido [1', 2': 1,5]pyrazolo[3,4‐c]pyridazine‐6,8‐diamine (6h): Prepared from 2‐methoxyphenylazomalononitrile 4h. Reaction time: 24 h. Color: Orange crystals. Yield: 74.5%. M.p.: 291‐292 °C. FT‐IR (KBr, ν, cm‐1): 3445, 3389, 3276, 3151 (NH2 groups), 2912 (CHaliph.), 2816 (OCH3), 1612 (C=N), 1538 (C=C). UV/Vis (DMF, λmax, nm, (log )): 269.6 (4.3). Anal. calcd. For C27H21N9O: C, 66.52; H, 4.34; N, 25.86. Found: C, 66.30; H, 4.10; N, 25.75%. 7‐((3‐Chlorophenyl)diazenyl)‐3,4‐diphenylpyrimido[1',2':1,5] pyrazolo[3,4‐c]pyridazine‐6,8‐diamine (6i): Prepared from 3‐ chlorophenylazomalononitrile 4i. Reaction time: 18 h. Color: Yellow crystals. Yield: 64%. M.p.: >300 °C. FT‐IR (KBr, ν, cm‐1): 3433, 3333, 3269, 3161 (NH2 groups), 3057 (CHarom.), 2914 (CHaliph.), 1612 (C=N), 1561 (C=C), 763 (C‐Cl). 1H NMR (400 MHz, DMSO‐d6, δ, ppm):7.34 ‐7.16 (m, 14H, Ph), 3.34 (s, 4H, 2NH2). UV/Vis (DMF, λmax, nm, (log )): 266 (4.5). Anal. calcd. forC26H18ClN9: C, 63.48; H, 3.69; N, 25.63. Found: C, 63.30; H, 5.60; N, 25.55%. 2.3. High temperature dyeing method (HT) 2.3.1. Materials Scoured and bleached polyester 100% (150 130 g/m2, 70/2 denier) was obtained from Misr Company for Spinning and Weaving El‐Mahala El‐Kobra, Egypt. The fabric was treated before dyeing with a solution containing non‐ionic detergent (Sera Wash M‐RK, 5 g/L) and sodium carbonate (2 g/L) in a ratio of 50:1 at 60 °C for 30 min, and then thoroughly washed with water and air dried at room temperature. 2.3.2. Dyeing The dye baths were prepared from the dye (2% weight of fabric) to a final liquor of 50:1 (w:w). The pH value of the bath was adjusted to 4.5‐5.0 with acetic acid (10%) in the presence of a 1:1 ratio of the dispersing agent (Sera Gal P‐LP). The temperature was raised to 130 °C at the rate of 7 °C/min, and dyeing continued for 60 min. After dyeing, the fabrics were thoroughly washed and then subjected to a surface reduction cleaning [(2 g NaOH + 2 g sodium hydrosulphite)/L]. The samples were heated in this solution for 30 min at 85 °C and then thoroughly washed and air‐dried. The dyeing was performed at 2% shade by high‐temperature techniques and gave generally deep and bright intense hues, ranging from yellow to orange‐yellow. 2.4. Color measurements and analyses 2.4.1. Color measurement The colorimetric parameters of the dyed polyester fabrics were determined on areflectance spectrophotometer (Table 1). The color yields of the dyed samples were determined by using the light reflectance technique performed on UV/VIS Spectrophotometer. The colorstrengths, expressed as K/S values, were determined by applying the Kubelka‐Mink Equation (1). K/S = [(1 − R)2 / 2R] − [(1 − Ro)2 / 2Ro] (1) where R = Decimal fraction of the reflectance of the dyed fabric; Ro= Decimal fraction of the reflectance of the undyed fabric; K = Absorption coefficient; S = Scattering coefficient. 2.4.2. Fastness tests 2.4.2.1. Fastness to washing After washing using 5 g/L of the nonionic detergent Hostapal CV and 2 g/L of sodium carbonate at 80 °C for 15 min, the dyed fabrics were tested by using ISO standard methods [11]. A specimen of dyed polyester fabric was stitched between two pieces of undyed cotton and wool fabrics, all of equal length, and then washed at 95 °C for 30 min. The staining on two pieces of undyed cotton and wool fabrics, all of equal length, and then washed at 95 °C for 30 min. The staining on the undyed adjacent fabrics was assessed according to the International Geometric gray scale: 1‐poor, 2‐fair, 3‐moderate, 4‐good, 5‐ excellent. 642 Deeb et al. / European Journal of Chemistry 5 (4) (2014) 639‐643 Table 1. Optical measurements of the synthesized monoazo disperse dyes 5a‐e and 6a‐i on the polyester fabrics†. Dyes a* b* C* h* L* ∆E* ∆L* ∆C* ∆H* K/S 5a 10.36 71.88 72.62 81.80 71.03 00.000 00.000 00.000 00.000 19.0 5b 19.20 82.38 84.59 76.88 66.16 14.570 ‐4.869 11.972 ‐6.727 24.5 5c 15.52 85.85 87.24 79.75 70.22 14.914 ‐0.806 14.618 ‐2.842 21.0 5d 17.03 83.62 85.08 81.35 84.91 15.380 ‐13.885 12.252 ‐4.422 21.5 5e 31.32 68.33 75.13 65.44 59.30 24.200 ‐11.730 2.508 ‐21.018 23.0 6a 20.87 78.52 81.25 75.12 20.87 00.000 00.000 00.000 00.000 16.0 6b 19.03 55.02 50.64 70.09 19.03 18.241 5.898 ‐16.608 ‐8.889 24.0 6c 11.55 58.16 61.25 39.89 37.55 60.783 32.801 ‐29.995 ‐40.784 19.5 6d 35.14 57.51 67.04 58.57 35.14 29.597 ‐15.191 ‐13.849 ‐21.294 21.9 6e 34.78 29.45 54.43 42.75 44.78 61.785 ‐30.323 ‐26.821 ‐37.278 22.0 6f 19.10 45.16 49.04 67.08 19.10 33.674 4.888 ‐32.214 ‐8.852 25.0 6g 12.90 62.11 63.44 78.27 12.90 8.418 2.539 16.810 6.948 23.5 6h 40.07 33.22 52.05 39.66 40.07 59.098 ‐32.735 ‐29.195 ‐39.607 21.0 6i 15.48 86.27 87.65 79.83 15.48 9.888 2.948 6.404 6.933 24.0 † a*, red/green axis; b*, yellow/blue axis; C*, color brightness; h*, hue value; L*, lightness of the color; ΔE*, total color difference; ΔL*, lightness difference; ΔC*, color difference; ΔH*, hue difference; K/S = Amount of dye absorbed on the surface of the fabrics. Table 2. Fastness properties of monoazo disperse dyes 5a‐e and 6a‐i on polyester fabrics. Dyes Washing Acidic perspiration Rubbing Sublimation at 180 °C Light (40 h) Dry Wet 5a 4 3‐4 4 4 4 6‐7 5b 4 3‐4 4 4 3‐4 6‐7 5c 4 3‐4 4 4 4 6‐7 5d 4 3‐4 4 4 3‐4 6‐7 5e 4 3‐4 4 4 4 6‐7 6a 4 4 4 4 4 5 6b 4 4 3‐4 3‐4 4 4‐5 6c 4 4 4 4 4‐5 5‐6 6d 4 3‐4 4 4 4 5‐6 6e 4‐5 4‐5 4 4 4 6 6f 4 3‐4 3‐4 4 4 5 6g 4‐5 3‐4 4 4 4 6 6h 4 4‐5 4 4 4 5 6i 4‐5 3‐4 3‐4 4 4‐5 4‐5 2.4.2.2. Fastness to perspiration The samples were prepared by stitching a piece of dyed polyester fabric between two pieces of cotton and wool fabrics, all of equal length, and then immersed in the acid or alkaline solution for 30 min. The staining on the undyed adjacent fabrics was assessed according tothe following gray scale: 1‐poor, 2‐ fair, 3‐moderate, 4‐good, 5‐excellent. The acid solution (pH =4.5) contains sodium chloride (10 g/L), sodium dihydrogen orthophosphate (1 g/L) and histidine monohydrochloride (0.25 g/L). The alkaline solution (pH = 8.7) contains sodium chloride (10 g/L), disodium orthophosphate (1 g/L) and histidine monohydrochloride (0.25 g/L). 2.4.2.3. Fastness to light Light fastness was determined by exposing the dyed polyester on a Xenotest 150 (Original Hanau, chamber temperature: 25‐30 °C, black panel temperature: 60 °C, relative humidity: 50‐60%, dark glass UV filter system) for 40 h. The changes in color were assessed according to the International Geometric blue scale: 1‐poor, 3‐moderate, 4‐good, 6‐very good, 8‐excellent. 2.4.2.4. Fastness to sublimation This test was made according to the ISO/R, 105/IV‐1968 pt. 2. The dyed sample was sandwiched between two undyed samples (one from cotton and the other from the same fiber under test) and then placed in iron tester (Yasuda no. 138) at 180 °C for 30 seconds. Change in color of the‐dyed samples and staining of the‐undyed ones were assessed using International Geometric Grey Scale (1‐5; 1‐poor, 2‐fair, 3‐moderate, 4‐good, 5‐excellent). 2.4.2.5. Fastness to rubbing Two pieces of the dyed fabric (one dried and the other completely wetted with distilled water) were placed alternatively on the base of the Crockmeter, so that it rested flat on the abrasive cloth with its long dimension in the direction of rubbing. A square of white testing cloths were allowed to slide on the tested fabric back and forth twenty times by making ten complete turns of the crank according to the international standard procedures. The same procedures were applied to the wetted sample. The staining on the white testing cloth was assessed according to the International Geometric grey scale. 3. Results and discussion 3‐Amino‐4,5‐diphenyl‐1H‐pyrazolo[3,4‐c]pyridazine 2, was prepared in 85% yield, as yellow crystalline (M.p. 244‐245 °C) according to the reported procedures [7] by refluxing 3‐chloro‐ 5,6‐diphenylpyridazine‐4‐carbonitrile 1 with hydrazine hydrate for 3 hours, (Scheme 1). Compound 2, when reacted with ethyl azobenzene acetoacetate derivatives 3a‐e in a mixture of ethanol and pyridine at refluxing temperature yielded 7‐arylazo‐6‐methyl‐ 3,4‐diphenylpyrimido[1`,2`:1,5]pyrazole[3, 4‐c]pyridazin‐ 8(5H)‐one derivatives 5a‐e (Scheme 2). Compound 2, when reacted with the azobenzene malononitrile derivatives 4a‐I in ethanol at refluxing tempera‐ ture yielded 6,8‐diamino‐7‐arylazo‐3,4‐diphenyl pyrimido [1`,2`:1,5]pyrazolo[3,4‐c]pyridazine 6a‐i (Scheme 3). The 3‐[4‐(arylazo)‐3,5‐disubstituted‐pyrazol‐1‐yl]‐4,5‐di phenyl‐1H‐pyraz‐olo[3,4‐c]pyridazines 5a‐e and 6a‐I were synthesized to assess their dyeing properties on polyester fabrics. The dyeing was performed at 2% shade by high‐ temperature techniques and gave generally deep and bright intense hues, ranging from yellow to orange‐yellow. The values of K/S of compounds 5a‐e and 6a‐i vary from 16 to 25. The introduction of different groups in dyes 5a‐e and 6a‐i increases the strength of K/S values and deepens the color compared with the parent dyes 5a and 6a, respectively (Table 1). The values of K/S for the dyes 5a‐c,e derived from ethyl azobenzene acetoacetate derivatives 3a‐c,e with 3‐amino pyrazolopyridazine 2 were greater than the corresponding Deeb et al. / European Journal of Chemistry 5 (4) (2014) 639‐643 643 dyes 6a‐c, e derived from azobenzene malononitrile deriva‐ tives 4a‐c, e with the same 3‐aminopyrazolopyridazine 2 on dyed polyester fibers. The color hues of the dyes 5a‐e and6a‐i on polyester fabrics are shifted towards the reddish and yellowish directions on the red‐green and yellow‐blue axes, respectively. Most influences that can affect fastness are light, washing, heat, perspiration, and atmospheric pollution. Conditions of such tests are chosen to correspond closely to treatments employed in manufacture and ordinary use conditions [11]. Results are given after usual matching of tested samples against standard reference (the grey scale) [11‐13]. The results revea‐ led that these dyes have good‐excellent fastness properties (Table 2). 4. Conclusions A set of 14 disperse dyes 5a‐e and 6a‐i were synthesized by reaction of3‐amino‐4,5‐diphenyl‐1H‐pyrazolo[3,4‐c]pyrida‐ zine 2 with ethyl arylazo acetoacetate and arylazo malono‐ nitrile derivatives. All of them were investigated for their dyeing characteristics on polyester. The dyed fabrics exhibit very good to excellent (4‐5) washing, perspiration, rubbing and sublimation fastness properties. The remarkable degree of levelness and brightness after washings is indicative of good penetration and the excellent affinity of these dyes for the fabric due to the accumulation of polar groups. This in combination with the ease of preparation makes them particularly valuable. References [1]. Abdel Galil, F. M.; Khalifa, F. A.; Abdin, T. S. Dyes Pigments 1990, 12, 49‐56. [2]. Rajagopal, R.; Seshadri, S. Dyes Pigments 1990, 13, 93‐105. [3]. Deeb, A.; Shaqra, S.; Abo El‐Fotoh, T.; Dief, S. Eur. Chem. Bull. 2014, 3(7), 627‐636. [4]. Deeb, A.; El‐Hossami, M.; Awad A. Eur. Chem. Bull. 2014, 3(8), 745‐ 751. [5]. Deeb, A.; Yassine, F.; Aouf, N.; Shehta, W. Int. J. Chem Tech Res. 2014, 6(1), 719‐729. [6]. Deeb, A.; Yassine, F.; Aouf, N.; Shehta, W. Eur. Chem. Bull. 2014, 3(1), 18‐23. [7]. Deeb, A.; Bayoumy, B.; Essawy, A.; Fikry, R. Heterocycles 1991, 32, 895‐900. [8]. Deeb, A.; Bayoumy, B.; Essawy, A.; Fikry, R. Heterocycles 1991, 32, 901‐907. [9]. Deeb, A.; Yassin, F.; Ouf, N.; Shehta, W. 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