Triple Cascade Synthesis of Dihydropyrimidones Using Lawsone and Heterocyclic Scaffolds with a Zinc Acetate Catalyst: Dyeing Efficiency on Nylon and Polyester Fabrics

This report presents an efficient triple cascade protocol for synthesizing new disperse dyes derived from different heterocyclic scaffolds, urea, and lawsone. This study proposes a novel modification protocol for disperse dyes that enhances their affinity for nylon substrates through the use of Zinc acetate catalyst, without inducing structural changes in the nylon fibers. Zinc acetate, which is favored due to its low-priced, low toxicity, and environmental benefits, has emerged as a valuable catalyst for this reaction. Triple cascade reactions (TCRs) represent a pivotal strategy in modern synthetic chemistry for the efficient construction of diverse organic molecules, owing to their high atom economy, operational simplicity, and environmentally benign nature. The recently synthesized disperse dyes demonstrate excellent dyeing properties on mutually nylon and polyester fibers. The Experimental finding demonstrated that the newly established dispersed dye had a significant effect on the dyeing performance and overall coloration properties of the substrates. The novel dyes show superior dyeing properties compared to lawsone, especially in term of vibrant shades, higher affinity, improved adsorption capacity and advanced tinctorial strength. Additionally, the percentage exhaustion, fixation, color strength (K/S), washing fastness & sublimation fastness properties are notably better in nylon-dyed samples than in polyester. These findings highlight the significant potential of these novels disperse dyes for nylon & polyester fiber. With commercialization, these dyes could provide a better alternative to conventional disperse dyes, offering broader benefits across various industries.