(+/-)-Camphor-10-sulfonic acid catalyzed atom efficient and green synthesis of triazolo[1,2-a]indazole-triones and spiro triazolo[1,2-a]indazole-tetraones

摘要

(+/-)-Camphor-10-sulfonic acid is used for the synthesis of triazolo[1,2-a]indazole-triones and spiro triazolo[1,2-a]indazole-tetraones by condensation reaction of dimedone, urazole and aromatic aldehydes or isatin. The noteworthy aspects of this new method are high yields, high atom efficiency, use of non-toxic solvent, mild conditions, simple workup and synthesis of complex molecules using an eco-friendly, inexpensive catalyst.