A novel route to 4-oxy/thio substituted-1H-pyrazol-5(4H)-ones via efficient cross-Claisen condensation

✍ Scribed by R. Venkat Ragavan; V. Vijayakumar

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2010
• Tongue: English
• Weight: 113 KB
• Volume: 48
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.558

✦ Synopsis

Abstract

α‐Oxy/thio substituted β‐keto esters were synthesized through an efficient cross‐Claisen condensation of oxy/thio substituted acetic acid ethyl esters with acid chlorides, which in turn converted in situ into 4‐oxy/thio substituted‐1__H__‐pyrazol‐5(4__H__)‐ones by the addition of hydrazine and its derivatives. This method has been found to be extremely fast, general, and useful toward the synthesis of inaccessible pyrazolones and synthetically demanding 4‐oxy/thio substituted pyrazolones. J. Heterocyclic Chem., (2011).