One‐Pot Synthesis of Pyrazoles through a Four‐Step Cascade Sequence. Issue 18 (28th February 2013)

• Record Type: Journal Article
• Authors: Hao, Lu; Hong, Jun‐Jie; Zhu, Jun; Zhan, Zhuang‐Ping
• Is Part Of: Chemistry. Volume 19:Issue 18(2013)
• Page Start: 5715
• Page End: 5720
• Publication Date: 2013-02-28
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201204322
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A one‐pot synthesis of 3, 4, 5‐ and 1, 3, 5‐pyrazoles from tertiary propargylic alcohols and <italic>para</italic>‐tolylsulfonohydrazide has been accomplished. The pyrazoles are formed through a four‐step cascade sequence, including FeCl₃‐catalyzed propargylic substitution, aza‐Meyer–Schuster rearrangement, base‐mediated 6π electrocyclization, and thermal [1, 5] sigmatropic shift. In this reaction, the 3, 4, 5‐ and 1, 3, 5‐pyrazoles are produced selectively according to different substituents in the starting alcohols.</p> </abstract>