Aluminium Chloride–Catalyzed Claisen Rearrangement: Synthesis of Polyheterocycles Containing Oxygen, Nitrogen, and Sulfur

Abstract

Synthesis of 1,8‐naphthyridine‐annulated polyheterocycles containing oxygen, nitrogen, and sulfur has been achieved by thionation and sequential Claisen rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl[1,8]‐naphthyridin‐2‐ones first by heating in 1,2‐dichlorobenzene for 1–2 h and then by anhydrous AlCl₃‐catalyzed Claisen rearrangement in dichloromethane for 1 h.

Keywords:

• aluminium chloride
• 1‐aryloxy‐4‐chlorobut‐2‐yne
• 1,8‐naphthyridin‐2‐one
• sequential Claisen rearrangement
• thio‐Claisen rearrangement

Acknowledgments

We thank the Council of Scientific and Industrial Research (CSIR) (New Delhi) for financial assistance. Two of us (R. I. and S. A.) are thankful to the CSIR (New Delhi) and the University Grants Commission (UGC) (New Delhi) respectively for their fellowships. We also thank the Department of Science and Technology (DST) (New Delhi) for providing UV‐vis and IR spectrometers under the Financial Assistance for Infrastructural Development of Science and Technology (FIST) Program.