Reaction of 3-benzoyl-1-methyl-4-phenyl-γ-piperidol with arylamines and arylhydrazines. Synthesis of 3-arylamino-1-oxo-1-phenylpropanes and 1,3 diarylpyrazoles and their fragmentation under electron impact

Upon heating in the presence of arylamines 3-benzoyl-4-hydroxy-1-methyl-4- phenylpiperidine decyclizes via a retroaldol type reaction with subsequent transamination of the intermediate Mannich base to give 3-arylamino-1-oxo-1- phenylpropanes. In the case of the use of arylhydrazines this γ-piperidol recyclizes to give 1,3-diarylpyrazoles and their 4,5-dihydro derivatives. The mass spectroscopic behavior of a series of 3-arylamino-substituted 1-phenylpropanones has been studied. © 2007 Springer Science+Business Media, Inc.