Disperse Dyes Based on Thiazole , Their Dyeing Application on Polyester Fiber and Their Antimicrobial Activity �

Various diazotized aryl amines were coupled with N-(4-nitrophenyl)-2-[(4-phenyl-1,3-thiazol-2-yl)amino]acetamide to give the corresponding various azo disperse dyes (D1-D13). ese dyes were applied to polyester �ber by HTHP method and their fastness properties were evaluated. Dyes were characterized by IR, elemental analysis, and NMR spectral studies. ese dyes showed very good antibacterial and antifungal activities.


Introduction
Disperse dyes are organic colorants with less water solubility and are applied in colloidal dispersions to hydrophobic textile �bers to produce desired color.�ith increasing use of polyester �bers and their blends, there has been signi�cant increase in the development of disperse dyes because over 90% of disperse dyes' usage is for the dyeing of polyester and its blends and with signi�cant increase in the world production of polyester �bers compared to other �bers.Many diazo components have been used in the production of disperse dyes in recent time [1][2][3][4][5][6].Derivatives of 2-aminothiazole [7][8][9] have been used as heterocyclic components since long for different disperse dyes.It was our main objective to synthesize [10][11][12][13] the disperse dyes consisting thiazole with azo substituent which further utilized to dye some hydrophobic �bers, to characterize, to evaluate their fastness properties.e dyes were screened for their antimicrobial properties because a large number of natural products and drugs comprises of this heterocyclic moiety [14][15][16].

Experimental
2.1.Materials and Methods.Melting points were determined in open capillary tubes and are uncorrected.e purity of dyes was determined by thin-layer chromatography (TLC) using silica gel-G-coated Al-plates.e visible absorption spectra were measured using Shimadzu UV-160 PC Spectrophotometer.Infrared spectra were recorded on a Shimadzu FT-IR 8400S model using KBr pellets. 1 H NMR spectra were recorded on a Varian 400 MHz Spectrophotometer using DMSO solvent and TMS as internal reference (chemical shis in , ppm).Elemental analysis was carried out on Perkin Elmer (USA) 2400 Series instrument.e fastness to light, wash, and sublimation was assessed in accordance with ISO 105.A convenient laboratory method was used for dyeing polyester to employ high temperature (130 ∘ C) and high pressure (24-30 psi.).e dye bath exhaustion (%E) of the dyed �ber was determined according to the method.e synthesized dyes were screened for their antimicrobial activity using the Kirby-Bauer method.All the compounds were screened for their in vitro antimicrobial activity against bacterial strains such as Escherichia coli, pseudomonas aeruginosa, Staphylococcus aureus, and fungi Candida albicans at 40 μg/mL concentration.(2).In 250 mL R.B.F., 4-nitroaniline (2.76 gm, 0.02 mole) in dry benzene (60 mL) was cooled to 0-5 ∘ C and 2-3 drops of TEA were added.Chloroacetyl chloride (2.26 mL, 0.02 mole) in dry benzene (20 mL) was slowly added to RBF with vigorous stirring then the reaction mixture was re�uxed for 3 hours.Excess of solvent was removed in vacuum and the residue stirred with water   maintaining the temperature at 0-5 ∘ C; stirring was continued for an hour, with positive test of nitrous acid on starch iodide paper.Excess of nitrous acid was destroyed by adding required amount of sulphamic acid.e resulting solution was used for coupling reaction (Figure 1).N-(4-nitrophenyl)-2-[(4-phenyl-1, 3-thiazol-2-yl) amino]acetamide (2) (0.01 mole) was dissolved in glacial acetic acid (30 mL) and cooled below 5 ∘ C. To this well stirred solution, above mentioned diazonium chloride solution was added drop wise maintaining the pH 7.5 to 8.0 by addition of aqueous sodium acetate (10% w/v).e stirring was continued for 3hours at 0-5 ∘ C. en reaction mixture was poured into ice to obtain dyes D 1 to D 13 , these dyes were �ltered and dried at 70 ∘ C and were recrystallized from acetone, the properties are presented in Table 1.

Results and Discussion
All the dyes showed good performance with polyester �ber.Table 2 shows moderate to fairly good light fastness.Compounds D 2 , D 6 , D 7 , D 11 , and D 12 showed better light fastness.e wash fastness of all the compounds was also of very good order.Introduction of terminal amino group for better dispersibility observed no notable change in the percentage exhaustion.Overall, synthesised dyes gave good dyeing on polyester �bers.All the samples showed moderate activities against E. coli and P. aeruginosa.Dyes D 3 , D 7 , D 10 , and D 11 showed good antibacterial activity against S. aureus, while D 3 and D 5 showed good antifungal activity against C. albicans.Standards used were Metranidazole and Flucanazole for the comparison purpose as described in Table 3 of synthesized dyes were con�rmed by spectral analysis as mentioned in Table 4.

Dyeing Procedure
e dyeing of the polyester fabric samples was carried out by HTHP dyeing method [17,18].
T 1: Yield, max, melting points, and nitrogen analysis of disperse dyes.