A novel three-component method for the synthesis of spiro[chromeno [4',3':4,5] pyrimido[1,2-b] indazole-7,3'-indoline]-2',6(9H)-dione
Tetrahedron, 2017, 73(19): 2806-2813.
A green, efficient, and rapid procedure for the synthesis of novel spiro[chromeno[4',3':4,5] pyrimido[1,2-b]indazole-7,3'-indoline]-2',6(9 H)-dione derivatives has been developed by one-pot condensation of 4-hydroxy-2H-chromen-2-one, isatin, and 1H-indazole-3-amine, in the presence of acetic acid in EtOH. This method has the advantages of operational simplicity, and high yield of products via a simple experimental and work-up procedure as compared to the conventional methods. The reaction mechanism and substrate scope of this novel reaction is briefly discussed.
Spiro[chromeno[4 ',3 ':4,5] pyrimido[1,2-b] indazole-7,3 '-indoline]-2 ',6(9 H)-dione derivatives; Michael reaction; One-pot synthesis; Multi-component reaction