Rearrangements of N-heterocyclic carbenes of pyrazole to 4-aminoquinolines and benzoquinolines

Article abstract of DOI:10.1002/ejoc.201000507

1-Phenyl-substituted pyrazolium salts, formed by quaternization of pyrazoles with benzyl halides or long-chain alkyl halides, deprotonate to pyrazol-3-ylidenes that undergo a sequence of ring-opening, ring-closure, and tautomerization to new substituted 4