Sulfamic acid: an efficient, cost-effective and recyclable catalyst for the synthesis of triazole[1,2-a]indazole-trione derivatives

Sulfamic acid (SA) is successfully utilized as a green, cost-effective and reusable catalyst for the synthesis of triazole[1,2-a]indazole-trione derivatives involving the one-pot, three-component condensation of urazole, aldehydes and cyclic beta-diketones in high yields in water as a sole solvent. The salient features of this new methodology are cheaper process, easy availability of the catalyst, mild conditions, versatility, and the catalyst could be recycled easily without affecting the catalytic activity.