Facile acidic hydrolysis and displacement reactions of 2-chloro-and 2,9-dichloro-1,10-phenanthroline

✍ Scribed by A. Paul Krapcho; Silvia Sparapani

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2008
• Tongue: English
• Weight: 257 KB
• Volume: 45
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570450435

✦ Synopsis

Abstract

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Treatment of 2‐chloro‐ or 2,9‐dichloro‐1,10‐phenanthroline with aqueous HBr or aqueous H~2~SO~4~ at 120°C yielded 1,10‐phenanthroline‐2(1__H__)‐one or 1,10‐dihydro‐1,10‐phenanthroline‐2,9‐dione, respectively. The hydrolysis of 2,9‐dichloro‐1,10‐phenanthroline with 37% aqueous HC1 led to the half hydrolyzed amide and the bis‐amide. Under comparable reactions conditions, using aqueous HBr, H~2~SO~4~ or HC1, 2‐chloropyridine was found to be hydrolytically stable. On the other hand, 2‐chloro‐ or 2,9‐dichloro‐1,10‐phenanthroline on heating with 57% aqueous HI afforded the HI salts of 2‐iodo‐ or 2,9‐diiodo‐1,10‐phenanthroline, which could be isolated. These salts on treatment with aqueous ammonium hydroxide led to good yields of 2‐iodo‐ and 2, 9‐diiodo‐1,10‐phenanthroline, respectively. Treatment of 2‐chloropyridine with 57% aqueous HI under similar reaction conditions led to 2‐iodopyridine in a 10% conversion.