Synthesis of Novel Acid Dyes with Coumarin Moiety and Their Utilization for Dyeing Wool and Silk Fabrics

This article describes the synthesis of some novel coumarin compounds to use as acid dyes by using compounds 1 4 as starting materials, which were prepared by interaction of 2-hydroxybenzaldehyde with ethyl 3-oxobutanoate, diethylmalonate, 4-nitrobenzenediazonium chloride and 4sulfobenzene-diazonium chloride, respectively. Compound 1 reacted with bromine and 2-cyanoacetohydrazide to give phenacyl bromide derivative 5 and 2-cyanoacetohydrazone derivative 6, respectively. Coupling of compound 6 with equimolar amount of 2-sulfo-4-((4-sulfophenyl) diazenyl)benzenediazonium chloride gave coumarin acid dye 8. Phenacyl bromide derivative 5 reacted with potassium cyanide in refluxing ethanol to produce compound 7, which on coupling with equimolar amount of 8-hydroxy-6-sulfonaphthalene-2-diazonium chloride and 8-hydroxy-3,6-disulfonaphthalene-1-diazonium chloride gave coumarin acid dyes 9 and 10, respectively. Interaction of compound 2 with 2-amino-5-((4-sulfophenyl)diazenyl)benzenesulfonic acid, benzene-1,4diamine and 3,3’-dimethoxy-[1,1’-biphenyl]-4,4’-diamine in refluxing ethanol afforded compounds 11, 12 and 14, respectively. Diazonium sulphate of compounds 12 and 14 coupling with 4-amino5-hydroxynaphthalene-2,7-disulfonic acid gave compounds 13 and 15, respectively. Cyclocondensation of compound 3 with ethyl 3-oxobutanoate, diethyl malonate and malononitrile afforded derivatives of 3-acetyl-2H-chromen-2-one 16, ethyl 2-oxo-2H-chromene-3-carboxylate 17 and 2imino-2H-chromene-3-carbonitrile 18, respectively. Reaction of sodium benzenesulfonate derivaCorresponding author. How to cite this paper: Bashandy, M.S., Mohamed, F.A., El-Molla, M.M., Sheier, M.B. and Bedair, A.H. (2016) Synthesis of Novel Acid Dyes with Coumarin Moiety and Their Utilization for Dyeing Wool and Silk Fabrics. Open Journal of Medicinal Chemistry, 6, 18-35. http://dx.doi.org/10.4236/ojmc.2016.61002 M. S. Bashandy et al. tive 4 with ethyl 3-oxobutanoate and hydrazine hydrate gave compounds 19 and 20, respectively. The structures of the newly synthesized compounds were confirmed by elemental analysis, UV/ VIS, IR, 1H NMR and Ms spectral data. The suitability of the prepared dyestuffs for dyeing of wool and silk fabrics has been investigated. The dyed fabric shows good light fastness, very good rubbing, perspiration, washing and excellent sublimation fastness. These dyes have been color shade from blue to violet with very good depth and levelness on fabrics. The dye bath exhaustion and fixation on fabric has been found to be very good.


Introduction
The considerable innovation has been witnessed in past three decades in the field of azo dye chemistry based on heterocyclic systems and studies in the synthesis of such derivatives have been reported [1]- [5].Most of the recent research has focused on structural variations of existing types, for example, variations in substituent, especially on the side chains of the coupling components.The use of heterocyclic coupling component and diazo components in the synthesis of azo dyes is well established, and the resultant dyes exhibit better tinctorial strength and brighter dyeing than those derived from aniline-based components.Most heterocyclic dyes of technical interest for application to textiles are derived from diazo components consisting of five-membered rings containing one sulphur heteroatom and to which a diazotisable amino group is directly attached.The ring may also possess one or more nitrogen heteroatoms and be fused to another aromatic ring.These diazo components are capable of providing red to blue color dyes that meet the rigorous technical and economical requirements demanded of them by both manufacturer and user.Intensive efforts have been made in the investigation of monoazo dyes in which a heterocyclic system replaces one of the usual carboxylic systems.Many different heterocyclic diazo components have been studied, especially derivatives of thiazole, imidazole, benzimidazole owing to the marked bathochromic effect of such groups [6]- [12].A majority of acid dyestuffs are sulphonic acid derivatives of azo dyes.The free dye acids are difficult to isolate and are hydroscopic in nature making it difficult to pack and store them.These dyes are invariably isolated as sodium salts.Coumarins are attractive and versatile molecules that find applications in various fields like medicine, perfumery, dyes, pigments, optical brighteners, lasers, optical data storage devices, solar cells [13]- [19].The coumarin is not fluorescent, but the introduction of an electron-withdrawing group such as a diazotized aromatic amine or an acetyl group makes it highly fluorescent.Coumarin establishes a family of dyes [20]- [24] that are applicable in different fields of science and technology [25]- [27].The present work was carried out with the following objectives, synthesis and identification of some newly acid dyes based on coumarin derivatives, and the possibility of its use in dyeing of wool and silk fabrics.

Chemistry
The present investigation deals with the synthesis of novel coumarin compounds to use as acid dyes by using compounds 1-4 as a starting materials, which were prepared by interaction of 2-hydroxybenzaldehyde with ethyl 3-oxobutanoate, diethylmalonate, 4-nitrobenzenediazonium chloride and 4-sulfobenzenediazonium chloride, respectively (Scheme 1).Structure of compound 3 was established on the basis of its elemental analysis and spectral data.Thus, IR spectrum of 3indicated absorption bands at v max = 3370 cm −1 for hydroxyl group, 1653 cm −1 for carbonyl group and 1456, 1290 cm −1 for nitro group. 1 H NMR spectrum showed three singlet signals at δ = 8.05, 10.30 and 11.78 ppm corresponding to H 6 of hyroxyphenyl ring, hydroxyl and formyl protons, respectively, two doublet signals, each doublet for two protons at δ = 7.95 and 8.32 ppm for H 2,6 and H 3,5 of nitrophenyl ring, respectively, two doublet signals, each doublet for one proton at δ = 7.17 and 8.14 ppm due to H 3 and H 4 of hyroxyphenyl ring, respectively.IR spectrum of compound 4 showed absorption bands at v max = 3462 cm −1 for hydroxyl group, v max = 1658 cm −1 for carbonyl group and v max = 1386, 1150 cm −1 for sulphate group. 1  ring, hydroxyl and formyl protons, respectively, two doublet signals, each doublet for two protons at δ = 7.76 -7.79 and 8.15 ppm for H 2,6 andH 3,5 of benzenesulfonate ring, respectively, two doublet signals, each doublet for one proton at δ = 7.17 and 8.06 -8.08 ppm due to H 3 and H 4 of hyroxyphenyl ring, respectively.
3-Acetyl-2H-chromen-2-one (1) reacted with bromine and 2-cyanoaceto-hydrazide to give phenacyl bromide derivative 5and 2-cyanoacetohydrazone derivative 6, respectively.Phenacyl bromide derivative 5 reacted with potassium cyanide in refluxing ethanol to produce 3-oxo propanenitrile derivative 7 (Scheme 2).The structure of compound 7 was established on the basis of their elemental analysis and spectral data.Thus, IR spectrum of compound 7 revealed absorption bands at v max = 2207 cm −1 for cyano group, v max = 1703 and 1636 cm −1 for cyclic carbonyl of coumarin and acyclic carbonyl, respectively.The mass spectrum of compound 7 showed a molecular ion peak at m/z = 213 and a base peak at m/z = 101.The methylene group in compound 6 proved to be highly reactive.Thus, 2-cyanoacetohydrazone derivative 6 underwent coupling with equimolar amount of 2sulfo-4-((4-sulfophenyl)-diazenyl)benzenediazonium chloride to give coumarin acid dye 8 (Scheme 2).The IR spectrum of coumarin acid dye 8 showed, two bi-forked characteristic absorption bands at v max = 3421 and 3350 cm −1 assignable to 2NH groups, another absorption bands at v max = 2212 cm −1 for cyano group and at v max = 1755 and 1657 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively.Mass spectrum of compound 8 showed a molecular ion peak at m/z = 681 and a base peak at m/z = 50.
3-Oxo-3-(2-oxo-2H-chromen-3-yl)propanenitrile (7) underwent coupling with equimolar amount of 8-hydroxy-6-sulfonaphthalene-2-diazonium chloride and 8-hydroxy-3,6-disulfonaphthalene-1-diazonium chloride to give coumarin acid dyes 9 and 10,respectively (Scheme 3).The structure of coumarin acid dyes 9 and 10 were established on the basis of their elemental analysis and spectral data.Thus, IR spectrum of compound 9 revealed absorption bands at v max = 3424 and 3320 cm −1 for OH and NH groups, respectively, v max = 2248 cm −1 for cyano group and at v max = 1710 and 1632 cm −1 for cyclic carbonyl of coumarin and acyclic carbonyl, respectively. 1H NMR spectrum of compound 9 showed two singlet signals at δ = 12.71 and 12.80 ppm corresponding to protons of OH and NH groups.IR spectrum of compound 10 revealed broad absorption band from v max = 3486 to 3380 cm −1 for OH and NH groups, v max = 2225 cm −1 for cyano group and at v max = 1710 and 1632 cm −1 for cyclic carbonyl of coumarin and acyclic carbonyl, respectively.Mass spectrum of compound 10 showed a molecular ion peak at m/z = 587 and a base peak at m/z = 219.
Interaction of ethyl 2-oxo-2H-chromene-3-carboxylate (2) with 2-amino-5-((4-sulfophenyl)diazenyl) benzene-sulfonic acid in refluxing ethanol afforded coumarin acid dye 11 (Equation 1).The structure of coumarin acid dye 11 was established on the basis of their elemental analysis and spectral data.Thus, IR spectrum of compound 11 revealed absorption bands at v max = 3325 cm −1 for NH group, v max = 1736 and 1617 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively.Mass spectrum of compound 11 showed a molecular ion peak at m/z = 573 and a base peak at m/z = 394.Interaction of compound 2 with benzene-1,4-diamine in refluxing ethanol afforded a single product identified as N-(4-aminophenyl)-2-oxo-2H-chromene-3-carboxamide (12) on the basis of elemental analysis and spectral data.Thus, IR spectrum of compound 12 showed, two bi-forked characteristic absorption bands at v max = 3458 and 3360 cm −1 assignable to amino group, v max = 3320 cm −1 for NH group and v max = 1702 and 1650 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively.Mass spectrum of compound 12 showed a molecular ion peak at m/z = 280 and showed other peaks at m/z = 173 corresponding to fragment (M + -C 6 H 7 N 2 ), m/z = 107as a base peak for fragment (C 6 H 7 N 2 + ) (Chart 1).Compounds 12 was suspended with stirring in concentrated sulfuric acid and cooled to 0˚C -5˚C then diazotized by adding sodium nitrite.After stirring at 0˚C for 1 h, the diazonium sulphate solution of compound 12 was added to dissolved coupler compound of 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid in 20% sodium hydroxide solution at 0˚C to give compound 13 (Scheme 4).IR spectrum of compound 13 revealed broad absorption band from v max = 3505 to 3273 cm −1 for hydroxyl, amino and NH groups and at v max = 1700 and 1648 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively.Mass spectrum of compound 13 showed a molecular ion peak at m/z = 654 and a base peak at m/z = 107.
In the same manner, compound 2 underwent condensation with 3,3'-dimethoxy- The elemental analysis and spectral data of the latter structure were in agreement with its assigned structure.Thus, IR spectrum of compound 14 revealed a broad absorption band from v max = 3400 to 3270 cm −1 due to amino and NH groups and v max = 1718 and 1658 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively.Besides, the mass spectrum was compatible with the molecular formula C 24 H 20 N 2 O 5 , m/z =416 confirmed structure 14.Diazonium sulphate of compound 14 coupling with 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid to give compound 15 (Scheme 5).IR spectrum of compound 15 revealed a broad absorption band from v max = 3509 to 3380 cm −1 due to hydroxyl, amino and NH groups, v max = 1726 and 1661 cm −1 for two carbonyl groups of coumarin ring and amide group, respectively and v max = 1449 cm −1 for N=N group.Mass spectrum of compound 15 showed a molecular ion peak at m/z = 791 and a base peak at m/z = 64.

Wool Fabric
Wool fabric of 310 g/m 2 , supplied by Golden Tex Co., Tenth of Ramadan-Egypt, was initially treated in an aqueous solution with a liquor ratio 50:1 containing 0.5 g/L sodium carbonate and 2 g/L nonionic detergent at 60˚C for 30 min, then thoroughly washed, and air dried at room temperature.

Silk Fabric
Degummed and bleached silk fabric (El-Khateib Co., Egypt) weighing 90 g/m 2 was used throughout this work.Before dyeing, the fabric was treated in an aqueous solution containing 2 g/l non-ionic detergent for 1 h at 90˚C and at a liquor ratio 50:1, then washed thoroughly in water and air dried at room temperature.

Chemistry
Melting points (˚C, uncorrected) were determined in open capillaries on a Gallen Kemp melting point apparatus (Sanyo Gallen Kemp, Southborough, UK).IR spectra (KBr) were recorded on FT-IR 5300 spectrometer and Perkin Elmer spectrum RXIFT-IR system (ν, cm −1 ).Pre-coated silica gel plates (silica gel 0.25 mm, 60 G F 254; Merck, Germany) were used for thin layer chromatography.The NMR spectra in (DMSO-d 6 ) were recorded at 400 MHz on a Varian Gemini NMR spectrometer (δ, ppm).Mass spectra were obtained on GC Ms-QP 1000 EX mass spectrometer at 70 ev.Elemental analyses were performed on Carlo Erba 1108 Elemental Analyzer (Heraeus, Hanau, Germany).All compounds were within ±0.4% of the theoretical values.Analyses were carried out by the Micro analytical Research Center, Faculty of Science, Cairo University and Al-Azhar University.

Effect of Dye Concentration on Percent of Dyeing Exhaustion
Figure 2 shows the exhaustion of the dyes on wool using different depth of shades (1% -5% o.w.f.) at pH 4 and 100˚C.Increasing the dye concentration reduces the exhaustion on wool.From these results, we can deduce that the dye 9 exhibits the most exhaustion value while the dye 11 shows the lowest one.

Effect of Dyeing Time on Percent of Dyeing Exhaustion
Figure 3 indicates the variation of dyeing time with temperature at pH 4 and (2% o.w.f.) dye concentration.It is apparent that the dye-fibre reaction is characterized by fast initial rate followed by slower rate, which levels off within the last 30 min of dyeing process.From these results, we can deduce that the dye 9 shows the most exhaustion value while the dye 11 shows the lowest one.

Effect of pH on Percent of Dyeing Exhaustion
Table 2 and Figure 4 show the effect of pH on the exhaustion of acid dyes on silk fibre.The data revealed that at lower dyeing pH values (pH 5), the substantivity of the acid dyes on silk is virtually high.From these results, we can deduce the acid dye 9 exhibits the most exhaustion value because this dye has lower molecular weight than others.The low substantivety of acid dye 10 is due to high molecular weight, which decreases substantivety.Although the dye 10 has higher molecular weight than dye 11, it is more substantivety, because it contains diazo component.

Effect of Dye Concentration on Percent of Dyeing Exhaustion
Figure 5 shows the exhaustion of the dyes on silk using different depth of shades (1% -5% o.w.f.) at pH 5 and 100˚C.Increasing the dye concentration reduces the exhaustion on silk.From these results, we can deduce the dye 9 is the most exhaustion value while the dye 11 is the lowest one.

Effect of Dyeing Time on Percent of Dyeing Exhaustion
Figure 6 indicates the variation of dyeing time with temperature at pH 5 and (2% o.w.f.) dye concentration.It is apparent that the dye-fibre reaction is characterized by fast initial rate followed by slower rate, which levels off within the last 30 min of dyeing process.From these results, we can deduce the acid dye 9 shows the most exhaustion value while the dye 11 is the lowest one i.e. increasing the time of dying, this leads to the increasing of the exhaustion values.

Colorimetric and Fastness Properties for All Dyeings
The colorimetric CIE L * a * b * C * h˚ data of the dyed wool and silk using the dye are shown in Table 3.The colour parameters were evaluated by means of the Cielab system and the modified CIEL * C * H˚ (D65/10˚) system.The following colour parameters for the dyed samples were obtained by the digital Cielab system: L*lightness, a*-redness if positive coordinate, or greenness if negative coordinate, b*-yellowness if positive coordinate, or blueness if negative coordinate, C*-chromaticity, Ho-hue of the colour, X-coordinate x, Y-coordinate y, Z-coordinate z [32].As shown in Table 4, the fastness to washing, rubbing and perspiration of all samples dyed with the dye was excellent to very good irrespective to the fabric used.Chromatic parameters were determined in comparison for samples dyed with all dyes.The light fastness of the dyes was found to       depend on the mobility of electrons through conjugated system from conjugated system from thiazole ring with coupler compounds afforded a good value of light fastness.The visible absorption spectra of some dyes showed that colours of dyes in the range are blue-purple, in addition, others in range are yellow-brown.The fastness of dyed fabrics to water, washing, alkaline and acid perspirations and rubbing was found to be very high irrespective of degree of sulphonation in the coupling component.

4 doublet
signal for one proton at δ = 7.62, 7.85 ppm corresponding to H 8 and H 7 of coumarin, respectively, besides two doublet signals each doublet signal for two protons at δ = 7.78 and 8.52 ppm corresponding to H 2,6 and H 3,5 of benzenesulfonate ring, respectively.IR spectrum of compound 20 revealed an absorption broad band at v max = 3384 for OH groups, v max = 1486 cm −1 corresponding to N=N group and two absorption bands at v max = 1384 and 1132 cm −1 for SO 2 group.Mass spectrum of compound 20 showed a molecular ion peak at m/z = 552 (M + -2N 2 ) and showed other peaks at m/z = 450 corresponding to fragment (C 20 H 15 N 6 O 5 S + ) and m/z = 295 for fragment (C 14 H 10 N 6 O 2 + ) (Chart 3).

1 .
Effect of pH and Dyeing Temperature on Percent of Dyeing Exhaustion Table

Figure 2 .
Figure 2. Exhaustion of acid dyes 8-11 on wool at various concentrations at pH 4.

Figure 4 .
Figure 4. Exhaustion of acid dyes 8-11 on silk at various pH values.

Figure 5 .
Figure 5. Exhaustion of acid dyes 8-11 on silk at various concentrations at pH 5.
H NMR spectrum of 16 revealed three singlet signals at δ= 2.53, 8.42 and 8.80 ppm for methyl, H 5 and H 4 of coumarin, respectively, two doublet signals each doublet signal for one proton at δ= 7.65, 8.25 ppm corresponding to H 8 and H 7 of coumarin, respectively, besides two doublet signals each doublet signal for two protons at δ= 8.08 and 8.59 ppm corresponding to H 2,6 and H 3,5 of nitrophenyl ring, respectively.IR spectrum of compound 17 revealed an absorption bands at v max = 1741 and 1705 cm −1 for two carbonyl groups of coumarin ring and ester group, respectively, v max = 1521 cm −1 corresponding to N=N group and two absorption bands at v max = 1338 and 1251 cm −1 for nitro group. 1 H NMR spectrum of 17 revealed triplet and quartet signals at δ= 1.30 and 4.30 ppm, respectively corresponding to protons of methyl and methylene of ester group, respectively, two singlet signals at δ= 8.40 and 8.89 ppm for H 5 and H 4 of coumarin, respectively, two doublet signals each doublet signal for one proton at δ = 7.60, 8.19 ppm corresponding to H 8 and H 7 of coumarin, respectively, besides two doublet signals each doublet signal for two protons at δ = 8.03 and 8.52 ppm corresponding to H 2,6 and H 3,5 of nitrophenyl ring, respectively.
IR spectrum of compound 18 revealed an absorption band at v max = 3337 for NH group, v max = 2205 for cyano group, v max = 1556 cm −1 corresponding to N=N group and two absorption bands at v max = 1338 and 1251 cm −1 22 M. S. Bashandy et al.Chart 1. Fragmentation pattern for compound 12. Scheme 4. Synthetic pathways for compounds 12 and 13.Scheme 5. Synthetic pathways for compounds 14 and 15.Scheme 6. Synthetic pathways for compounds 16-18.

Chart 2. Fragmentation pattern for compound 18. Scheme
for nitro group.Mass spectrum of compound 18 showed a molecular ion peak at m/z = 321 (M + +2) and showed other peaks at m/z = 319 (M + ), m/z = 170 corresponding to fragment (M + -C 6 H 3 N 3 O 2 ), m/z = 150 for fragment (M + -C 10 H 5 N 2 O), m/z = 106 for fragment (C 7 H 6 O + ), m/z = 77 for fragment (C 6 H 5 Reaction of sodium benzenesulfonate derivative 4 with ethyl 3-oxobutanoate and/or hydrazine hydrate gave compounds 19 and 20, respectively (Scheme 7).IR spectrum of compound 19 revealed an absorption bands at v max = 1754 and 1672 cm −1 for two carbonyl groups of coumarin ring and acetyl group, respectively, v max = 1564 cm −1 corresponding to N=N group and two absorption bands at v max = 1382 and 1122 cm −1 for SO 2 group.1HNMR spectrum of 19 revealed triplet signal at δ = 2.57 ppm corresponding to protons of methyl group, two singlet signals at δ = 8.19 and 8.80 ppm for H 5 and H 4 of coumarin, respectively, two doublet signals each 7. Synthetic pathways for compounds 19 and 20.
Hydroxybenzaldehyde (1.22 g, 0.01 mol) was dissolved in water (20 mL) containing (0.4 g, 0.01 mol) of sodium hydroxide and (4.24 g, 0.04 mol) of sodium carbonate during the period of 30 min at 0˚C.The resulting solution was added slowly to a solution of diazonium chloride of 4-nitroaniline (1.38 g, 0.01 mol) in water at 0˚C -5˚C.The reaction mixture was stirred for 1 h at 0˚C and then allowed to warm slowly to room temperature.

Table 1 .
Exhaustion of acid dyes 8-11 on wool at various pH values.

Table 2 .
Exhaustion of acid dyes 8-11 on silk at various pH values.

Table 3 .
Colorimetric data of the dyed wool and silk fabrics using acid dyes 8-11 (2% o.w.f.) at 100˚C and at pH 4. : chromaticity; Ho: hue of the colour; E * : total colour; a * : redness if positive coordinate, or greenness if negative coordinate; b * : yellowness if positive coordinate, or blueness if negative coordinate.