Synthesis, characterization, and antimicrobial evaluation of sulfonamide-based azo disperse dyes derived from sulfaguanidine and sulfisoxazole coupled with barbituric and thiobarbituric acids for polyester printing

Abstract

By diazotizing sulfaguanidine and sulfisoxazole and then coupling with derivatives of barbituric and thiobarbituric acids, a new class of sulfonamide-based azo disperse dyes was produced. The chemical structures of the resulting dyes had been confirmed by elemental analysis, FT-IR, and ¹H-NMR. Screen printing was used to apply the colors to 100% polyester fabrics, and thermofixation was then performed under optimal conditions. The addition of barbituric and thiobarbituric moieties significantly improved conjugation and dye–fiber affinity, resulting in higher color depth, according to colorimetric properties assessed in terms of CIE Lab* coordinates and color strength (K/S values). Furthermore, antimicrobial assays showed that many compounds exhibit antimicrobial activity against both Gram-positive and Gram-negative bacteria, either as sole compounds or on fabrics. Compound 5D demonstrated the highest antimicrobial efficacy against fabrics, with more than 99.9% reductions in the microbial pathogens S. aureus and P. aeruginosa, followed by 5C and 5A. Interestingly, 5B was inactive against bacteria but showed anti-candida activity against C. albicans. The observed bioactivity was influenced by the presence of sulfonamide pharmacophores in conjunction with azo-linked heterocyclic systems. This study demonstrates the possibility of generating multifunctional fabrics with both attractive and antibacterial properties by incorporating bioactive sulfonamide molecules into disperse dyes.

KEY WORDS: Azo disperse dyes, Sulfonamide dyes, Thiobarbituric acid, Polyester printing, Antimicrobial dyes

Bull. Chem. Soc. Ethiop. 2026, 40(11), 2443-2458

DOI: https://dx.doi.org/10.4314/bcse.v40i11.12