An efficient N,N′‐dioxide–lanthanum(III) complex catalytic system has been developed for the diastereo‐ and enantioselective Michael‐initiated ring‐closure (MIRC) reaction of 2‐cyano‐3‐arylacrylates with 2‐bromomalonates. Various chiral cyclopropanes with multiple substitutions were obtained in high yields (up to 93%) with excellent dr (>95:5 dr) and good ee values (up to 91% ee). The catalytic system
A one-pot two-step microwave-assisted synthesis of N1-substituted 5,6-ring-fused 2-pyridones
作者:Marco Radi、Gian Paolo Vallerini、Alessia Petrelli、Paolo Vincetti、Gabriele Costantino
DOI:10.1016/j.tetlet.2013.10.054
日期:2013.12
A fast, versatile and practical one-pot, two-step microwave-assisted protocol for the direct synthesis of N1-substituted 5,6-ring-fused 2-pyridones has been developed. The present method proved to be effective on a series of commercially available aldehydes, ketones and amines and could be profitably exploited in drug-discovery settings for the rapid identification of biologically relevant hit compounds. (C) 2013 Elsevier Ltd. All rights reserved.
Synthesis of highly stable CoFe2O4 nanoparticles and their use as magnetically separable catalyst for Knoevenagel reaction in aqueous medium
作者:Kula Kamal Senapati、Chandan Borgohain、Prodeep Phukan
DOI:10.1016/j.molcata.2011.02.007
日期:2011.4
Synthesis of spine! cobalt ferrite magnetic nanoparticles (MNPs) with average sizes in the range 40-50 nm has been achieved using a combined sonochemical and co-precipitation technique in aqueous medium without any surfactant or organic capping agent. The nanoparticules form stable dispersions in aqueous or alcoholic medium. The uncapped nanoparticles were utilized directly as a reusable catalyst for Knoevenagel reaction in aqueous ethanol (1:3). Compartmentation and recovery of the catalyst from reaction medium was done with the aid of an external magnet. High yield of corresponding Knoevenagel products were obtained within a very short time in presence of just 5 mol% of the catalyst at 50 degrees C. (C) 2011 Elsevier B.V. All rights reserved.