Copper(I)-catalyzed synthesis of 1-arylpyrazolo[5,1-b]quinazolin-9(1H)-one via intramolecular alkyne hydroamination

The 1-arylpyrazolo[5,1-b]quinazolin-9(1H)-one derivatives were obtained via intramolecular alkyne hydroamination reaction of 2-amino-N′-arylbenzohydrazide and alkynal diethyl acetal in the presence of CuBr and Cs2CO3. This new procedure provides an efficient method to construct fused tricyclic heterocycle containing both pyrazole and quinazoline analogues.

Graphical abstractDownload full-size imageThe 1-arylpyrazolo[5,1-b]quinazolin-9(1H)-one derivatives were obtained via intramolecular alkyne hydroamination reaction of 2-amino-N′-arylbenzohydrazide and alkynal diethyl acetal in the presence of CuBr and Cs2CO3. This new procedure provides an efficient method to construct fused tricyclic heterocycle containing both pyrazole and quinazoline analogues.