Premium
One‐Pot Synthesis of Pyrazoles through a Four‐Step Cascade Sequence
Author(s) -
Hao Lu,
Hong JunJie,
Zhu Jun,
Zhan ZhuangPing
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201204322
Subject(s) - cascade , sigmatropic reaction , sequence (biology) , chemistry , base (topology) , substitution (logic) , cascade reaction , combinatorial chemistry , pyrazole , one pot synthesis , stereochemistry , medicinal chemistry , organic chemistry , catalysis , mathematics , computer science , programming language , mathematical analysis , biochemistry , chromatography
A one‐pot synthesis of 3,4,5‐ and 1,3,5‐pyrazoles from tertiary propargylic alcohols and para ‐tolylsulfonohydrazide has been accomplished. The pyrazoles are formed through a four‐step cascade sequence, including FeCl 3 ‐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.