Synthesis of gold nanoparticles decorated on sulfonated three‐dimensional graphene nanocomposite and application as a highly efficient and recyclable heterogeneous catalyst for Ullmann homocoupling of aryl iodides and reduction of p‐nitrophenol

Gold nanoparticles were decorated onto sulfonated three‐dimensional graphene (3DG‐SO₃H) through spontaneous chemical reduction of HAuCl₄ by 3DG‐SO₃H. This nanocomposite exhibited excellent catalytic activity for the synthesis of symmetric biaryls via the Ullmann homocoupling of aryl iodides in an aqueous medium. Additionally, this nanocomposite was used as a catalyst for the reduction of p‐nitrophenol to p‐aminophenol. The catalyst could be used more than six times successively without significant deactivation.     

[Hmim]TFA catalyzed multicomponent reaction: direct,mild, and efficient procedure for the synthesis of 1,2-dihydroquinazoline derivatives

4-Substituted-spiro-1,2-dihydroquinazolines and related compounds were synthesized by direct reaction of 2-aminobenzophenones, isatin, or 1,2-diketone derivatives and ammonium acetate in the presence of dual role catalyst-solvent ionic liquid, [Hmim]TFA. Excellent conversion of starting materials was achieved to the desired 1,2-dihydroquinazoline products.