Synthesis of arylazothiazole dyes in the presence of sulfonated nanostructures

ABSTRACT

In this research, SO₃H-activated structures such as Fe₃O₄@SiO₂-SO₃H, chitosan-SO₃H (CS-SO₃H), starch-SO₃H and montmorillonite-SO₃H (MMT-SO₃H) were used as solid acid catalysts for the synthesis of 2-amino-5-aryl-azothiazole dyes from the diazo coupling reactions of aromatic amines with 2-aminothiazole. The experimental results showed among studied solid acids, MMT-SO₃H was the most effective nanocatalyst in this process. This efficient approach offers attractive advantages, such as excellent yields and high purity, the use of nontoxic and heterogeneous catalyst, inexpensive procedure and easy isolation of products, shorter reaction times and milder conditions. The present methodology is much simpler and greener than the previous synthetic methods published to date.

GRAPHICAL ABSTRACT

KEYWORDS:

• 2-aminothiazole
• azo dyes
• azothiazole
• solid acid
• sulfonated structures

Acknowledgements

We are thankful to the Research Council of the University of Kashan for the partial support of this work.

Disclosure statement

No potential conflict of interest was reported by the authors.