Rearrangement of arylhydrazones of aromatic and arylaliphatic carbonyl compounds to biphenyl derivatives. 3

Article abstract of DOI:10.1021/jo00314a018

The behavior toward polyphosphoric acid of arylhydrazones of aromatic carbonyl compounds (anisaldehyde, substituted benzophenones, (4-methoxyphenyl)glyoxylic acid esters) and arylaliphatic ketones (4-methoxy- and 4-aminoacetophenone) is described.Biphenyl derivatives are formed through a <5,5> sigmatropic rearrangement, which often occurs in competition with the expected Fischer indole synthesis and, in the case of the 4-amino-acetophenone 2,6-dimethylphenylhydrazone, with a completely new <3,5> sigmatropic rearrangement.