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Introduction
Sulphur-organic compounds have a variety of applications. Since 1970, 2-aminothiophenes have attracted tremendous interest because of their applications not only in drug discovery but also in agriculture, pesticides, dyes. As an important biological entity and as key synthetic precursors, these have been shown to belong to a variety of target family classes (Sabnis et al. , 1999; Elgemeie et al. , 1997a, 1997b, 1998, 2001, 2006). Thus, due to the importance of thiophene chemistry to material applications, new thiophene-based dyes synthetic techniques have been reviewed because thiophene-based derivatives have an antimicrobial, antibacterial activity and potent anticancer activity (Romagnoli et al. , 2013).
Most thiophene derivatives are either produced from ring synthesis or starting from thiophene (Majer et al. , 2009), or simple alkyl thiophene (Tumer et al. , 2004; Gabera and Bagleyb, 2011; Wen et al. , 2013). A conceptually new method for synthesis of tetra-substituted thiophenes-based dyes involves two steps: first synthesis for tetra-substituted thiophenes, and second reaction with diazonium salt of aromatic amines.
The alkylation of 2 was achieved by addition of two equivalent amounts of phenacyl bromide in an alkaline medium, leading to the S alkylated products which underwent ready cyclisation, afford respective substituted thiophene ring 5 . The latter products react with the diazonium salt of aromatic amines 6 to afford our target dye stuff 7, as shown in Scheme 1 and Table I. The structure of the synthesised dyes were established and confirmed for the reaction products on the basis of their elemental analysis and spectral data (IR and 1H-NMR).
The suitability of the prepared dyestuffs for traditional printing on polyester and polyamide fabrics has been investigated. The prints obtained from dyes possess high colour strength as well as excellent overall fastness properties.
Experimental
Materials
The following materials were used in the study reported here:
Fabrics:
Polyamide 6 (PA) of 212 g/m2 supplied by El-Nasr Company for Spinning, Weaving and Knitting was treated with a solution containing 5 g/l soap at 50°C for 15 minutes, and then thoroughly washed and dried at room temperature.
Polyester fabric (PE) knitted fabric of 150 g/m2, supplied by a private sector company, was treated with a solution containing 1 g/l non-ionic detergent at 70°C for 1/2 hour thoroughly washed and air dried at...