Synthesis 2004(8): 1269-1273  
DOI: 10.1055/s-2004-822353
PAPER
© Georg Thieme Verlag Stuttgart · New York

A Short Route to Heteroarylcarbazoles: Synthesis of New Pyrazolylcarbazoles and Carbazolylquinolines

Rajagopal Nagarajan, Paramasivan T. Perumal*
Organic Chemistry Division, Central Leather Research Institute, Adyar, Chennai - 600 020, India
Fax: +91(44)24911589; e-Mail: ptperumal@hotmail.com;
Further Information

Publication History

Received 26 September 2003
Publication Date:
03 May 2004 (online)

Abstract

A short synthesis of pyrazolylcarbazoles from 9-alkylcarbazoles in three steps is reported. The acetylcarbazoles prepared by the acetylation of carbazoles with acetic anhydride catalyzed by BiCl3 were converted into chloroaldehydes with Vilsmeier reagent. Condensation of chloroaldehydes with hydrazine followed by cyclization yield the pyrazolylcarbazoles. Carbazolyl chalcones were prepared by the condensation of carbazole-3-aldehyde with o-aminoacetophenone and cyclized to carbazolylquinolone using several catalysts. Cyclization of carbazolyl chalcones with the Vilsmeier reagent yields a mixture of carbazolylquinoline carbaldehydes.