One-Pot Four Component Synthesis of 3-Amino-1-(1H-indol-2-yl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine Derivatives Mediated by [DBUH][OAc]

Abstract

One-pot, four component, green, and efficient synthesis of 3-amino-1-(5-nitro-1H-indol-2-yl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine derivatives by reaction of phthalic anhydride with hydrazine hydrate, 5-nitro-1H-indole-3-carboxaldehyde–indole-3-carboxaldehydes and malononitrile–ethyl cyanoacetate in the presence of [DBUH][OAc] at 60–65°C is developed. The method is characterized by short reaction time, high yields, and purity of products formed.