Ultrasound promoted synthesis of beta-amino carbonyl compounds in aqueous hydrotropic medium at ambient temperature is reported. The remarkable features of the new procedure are shorter reaction time, excellent yields in aqueous medium, cleaner reaction profile and simple experimental and work-up procedure. (C) 2011 Elsevier B.V. All rights reserved.
Cooperative Catalysis of <i>p</i>-Aminophenol and Titanocene Dichloride in Direct Mannich Reactions with Acetone
A new binary acid system featuring an air stable organometallic precursor, titanocene dichloride and a simple Brønsted acid–base compound, was developed. The new catalyst system allowed for mild and highly efficient direct three-component Mannich reactions of both aryl ketones and alkyl ketones, in particular, acetone and its derivatives with excellent yields. Mechanistic study elucidated the dramatic synergistic effect of the new binary acid system.