Simple and Convenient Methods for the Synthesis of Indolo[3,2-c]acridines

Abstract

The reaction of 2,3,4,9-tetrahydro-1H-carbazol-1-ones with anthranilic acid in POCl₃ yielded 7-chloro-5,6-dihydro-13H-indolo[3,2-c]acridines, while the same on reaction with isatin under the Pfitzinger reaction condition yielded 5,6-dihydro-13H-indolo[3,2-c]acridine-7-carboxylic acids. The latter reaction was carried out in different basic condition, because of, NaOH yielded more yield instead of KOH. Both the obtained products were treated with Pd/C in diphenyl ether to yield 13H-Indolo[3,2-c]acridines.

Keywords:

• 7-Chloro-5,6-dihydro-13H-indolo[3,2-c]acridine
• 5,6-dihydro-13H-indolo[3,2-c]acridine-7-carboxylic acids
• 13H-indolo[3,2-c]acridine
• 2,3,4,9-tetrahydro-1H-carbazol-1-ones

ACKNOWLEDGMENTS

Our sincere thanks go to the Chairman, NMR Research Centre, IISc, Bangalore, SAIF, IIT Madras, Chennai, and the Director, ISO Quality Assurance Cell, IICT, Hyderabad, for providing access to their NMR and mass spectral facilities.