Synthesis and Transformation of 3-Coumarinyl Methyl Ketone (Thio)Acylhydrazones and 5-Substituted 3-Acetyl-2-(3-coumarinyl)-2-methyl-1,3,4-oxadiazolines under Acetylating Conditions

✍ Scribed by Somogyi, László

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 397 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419940614

✦ Synopsis

Abstract

The synthesis of 3‐acetylcoumarin (thio)acylhydrazones 1a–e and their transformation to 5‐substituted 3‐acetyl‐2‐(3‐coumarinyl)‐2‐methyl‐1,3,4‐oxa(thia)diazolines 2a–f (cyclic isomers of the alternatively accessible diacylhydrazones, e.g. 1f–h) under acetylating conditions are described. Treatment of the acetylation products 2c–f with the acetylating agent Ac~2~O/ZnCl~2~ resulted in the unexpected formation of acylhydrazones 1c, d, i with cleavage of the oxadiazoline ring and simultaneous loss of the acetyl group. magnified image