Chemistry Letters, Vol.42, No.8, 927-929, 2013
Iron(III)-catalyzed Highly Efficient, One-pot Synthesis of Triazolo[1,2-a]indazoletriones and Spirotriazolo[1,2-a]indazoletetraones
Three-component coupling (3CC) of aldehyde, 1,3-dione, and 4-phenylurazole has been achieved in the presence of 10 mol % anhydrous FeCl3 in acetonitrile under reflux conditions to afford the corresponding triazolo[1,2-a]indazoletriones in excellent yields while the coupling of isatins with 4-phenylurazole and 1,3-diones gave the spirotriazolo[1,2-a]indazoletetraones under similar conditions.