A novel synthesis of 2‐aryl‐4‐piperidones by mannich cyclization of iminoketals

Abstract

2‐Aryl‐4‐piperidones have been synthesized by condensation between an aromatic aldehyde and a β‐aminoketone ethylene ketal, and further cyclization of the resulting iminoketal with dry hydrogen chloride or anhydrous p‐toluensulfonic acid. Alternatively, reaction of the above iminoketals with methyl fluorosulfonate followed by dry hydrogen chloride treatment and acid hydrolysis gives directly N‐methyl‐4‐piperidones. The application of these reactions to the synthesis of some 2‐aryl‐3‐acetylpyrrolidine systems is also described.

One-Pot Synthesis of Substituted Piperidinones and 3,4-Dihydropyrimidinones Using a Highly Active and Recyclable Supported Ionic Liquid Phase Organocatalyst

“…The literature survey again reveals that there are a number of methods for the synthesis of piperidinones, [26][27][28][29] but there is lot of scope to develop more advanced methods. The use of L-proline, as a homogeneous catalyst, for the synthesis of piperidinones is well explored in literature.…”