Synthesis of spiro[indolo[۲'۱-b]quinazoline-۶'۴'-pyrazolo[۴'۳-c]quinolin]-۱۲-ones

A highly efficient approach for the synthesis of spiro[indolo[۲'۱-b]quinazoline-۶'۴'-pyrazolo[۴'۳-c]quinolin]-۱۲-ones was reported by the combination of tryptanthrin, various aromatic amines, and ۳-methyl-۱-phenyl-pyrazol-۵(۴H)-ones in CH۳CN. Trichloroacetic acid (TCAA) catalyzed this reaction and desired products were obtained in good to high yields. Moreover, this protocol presented good tolerance and compatibility with a broad range of aromatic amines with variable substituents.

Keywords:

Tryptanthrin , Aromatic amine , ۳-methyl-۱-phenyl-pyrazol-۵(۴H)-one , Spiro compound.