Cyclization reactions of 2-(2-chloro-4-nitrophenylsulfonyl)-1-(2-thienyl)ethanone

✍ Scribed by Ai-Long Fan; Song Cao; Jing-Hua Xu; Zheng Zhang

• Publisher: Journal of Heterocyclic Chemistry
• Year: 1998
• Tongue: English
• Weight: 202 KB
• Volume: 35
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570350237

✦ Synopsis

Abstract

A new sulfonyl group‐containing heterocyclic compound 2‐(2‐chloro‐4‐nitrophenylsulfonyl)‐1‐(2‐thienyl)ethanone 2 was prepared from the corresponding sulfide 2‐(2‐chloro‐4‐nitrophenylthio)‐1‐(2‐thienyl)ethanone 1. Two different cyclization reactions of the compound 2 were discussed. In contrast to the tandem alkylation‐cyclization process [1], another cyclic procedure was described. In the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as a base and dimethylformamide as a solvent, compound 2 was treated with ethyl acrylate or methyl methacrylate at 50–55° to give the 1,4‐benzoxathiin 4,4‐dioxide 5 or 6 respectively via a tandem Michael conjugate addition‐cyclization process.