An efficient synthesis of spiroacridinone derivatives from the facile reaction of isatins, dimedone, and 5‐aminoindazole (6‐aminoindazole or 5‐aminoindole)

Abstract

We have developed a simple and facil protocol for the synthesis of tetrahydrospiro(indoline‐3,11′‐pyrazolo[4,3‐a]acridine)‐2,10′(7′H)‐dione, tetrahydrospiro(indoline‐3, 11′‐pyrazolo[3,4‐a]acridine)‐2,10′(7′H)‐dione, and tetrahydrospiro (indoline‐3,11′‐pyrrolo[3,2‐a]acridine)‐2,10′(7′H)‐dione via PTSA·H2O‐induced cyclization reaction from isatins, dimedone, and 5‐aminoindazole (6‐aminoindazole or 5‐aminoindole) in mixed solvent (EtOH and CH3CN). In this research, 5‐aminoindazole, 6‐aminoindazole, and 5‐aminoindole were effectively used to react with isatins and dimedone to give spiroacridinone derivatives. The advantages of this method are mild conditions, convenient manipulation, high yields, and a wide range of substrates.

Three‐component one‐pot synthesis of pyrazino[2,3‐a]acridine derivatives under catalyst‐free conditions

“…[ 9 ] Therefore, many novel procedures have been developed to the synthesis of acridine derivatives in recent years. [ 10–21 ]…”