Tetrakis(acetonitrile)copper(I) Hexafluorophosphate as an Efficient Catalyst for the Synthesis of Triazolo[1,2-a]indazole-1,3,8-trione and 2Hindazolo[2,1-b]phthalazine-trione Derivatives

Tetrakis(acetonitrile)copper(I) hexafluorophosphate, [Cu(CH3CN)4]PF6, was explored as an efficient catalyst to promote the three-component reaction of aryl aldehydes, dimedone and urazole or phthalhydrazide to afford the corresponding triazolo[1,2-a]indazole-1,3,8-trione and 2H-indazolo[2,1-b]phthalazine-trione derivatives respectively in high yields. The reactions were conducted at 80-100 °C under solvent-free conditions. The catalyst was easily prepared from available and inexpensive materials and was quantitatively recovered from the reaction by simple filtration and reused for a number of cycles with almost consistent activity