Carbon-14-labeled 2,3,7,8- and 1,2,7,8-tetrachlorodibenzofuran

✍ Scribed by Allan P. Gray; W. J. McClellan; V. M. Dipinto

• Book ID: 102373774
• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: French
• Weight: 479 KB
• Volume: 18
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2580180408

✦ Synopsis

Abstract

Both 2,3,7,8‐ and 1,2,7,8‐ tetrachlorodibenzofuran ‐U^14^C, specific activity 57 mCi/mmol, have been obtained in low yield but at < 98% purity via Pschorr cyclization of o‐phenoxyaniline ‐U^14^C, chlorination of the resultant dibenzofuran and separation of the tetrachloro isomers by hplc. The lower yields obtained in the Pschorr cyclization of “hot” o‐phenoxyaniline in comparison with the “cold” material are postulated to result from enhanced homolytic relative to heterolytic cleavage of the “hot” diazonium ion leading to a “hot” free radical which polymerizes. The completely anomalous results observed in the attempted palladium acetate‐mediated cyclization of diphenyl ether‐ U^14^C are likewise interpreted in terms of the intervention of a “hot” free radical.