Radikalreaktionen von N-Heterocyclen. I. Synthese und Struktur eines N,N-verknüpften Bipyrazols

✍ Scribed by Prof. Dr. Manfred Schulz; Dr. Liena Mögel; Dr. Werner Riediger; Dr. Nghiem-Xuan-Dung; Reiner Radeglia

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 584 KB
• Volume: 324
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/prac.19823240215

✦ Synopsis

Radical Reactions of N‐Heterocyclic Compounds. I. Synthesis and Structure of an N,N‐Linked Bipyrazole

5(3)‐Amino‐3(5)‐(phenylamino)‐pyrazole‐4‐carboxylic acid ethyl ester (1), which is a very good antioxidant, reacts under mild reaction conditions with dibenzoyl peroxide or with tert.‐butoxy radicals under formation of a bipyrazole 4. Evidence of the structure of 4 is given by ^1^H‐n.m.r., ^13^C‐n.m.r., i.r. and u.v. spectroscopic measurements, respectively and especially by ^15^N‐n.m.r. measurements of ^15^N labelled compounds 1 and 4. The bispyrazole 4 reacts with Pb(IV)‐acetate, the product isolated was the 5‐amino‐e‐anilino‐1‐(1‐anilino‐2‐cyano‐2‐ethoxycarbonylethenyl‐azo)‐pyrazole‐4‐carboxylic acid ethyl ester (7). The formation of this substance is a chemical proof of the structure of 4.