12-Tungstophosphoric acid (H3PW12O40) is found to be an efficient and recyclable catalyst in promoting a chemo- and regioselective condensation of hydrazines/hydrazides, diamines, and primary amines with various 1,3-dicarbonyl compounds in pure water at room temperature to afford pyrazoles, diazepines, and enaminones/enamino esters, respectively, in high yields.
Room-Temperature Synthesis of Pyrazoles, Diazepines, <font>β</font>-Enaminones, and <font>β</font>-Enamino Esters Using Silica-Supported Sulfuric Acid as a Reusable Catalyst Under Solvent-Free Conditions
highly efficient regio- and chemoselective condensation of hydrazines/hydrazides, diamines, and primary amines with various β-dicarbonyl compounds at room temperature to afford pyrazoles, diazepines, and β-enaminones/β-enaminoesters under solvent-free conditions within 5–15 min.
Greener and rapid access to bio-active heterocycles: room temperature synthesis of pyrazoles and diazepines in aqueous medium
作者:Vivek Polshettiwar、Rajender S. Varma
DOI:10.1016/j.tetlet.2007.11.017
日期:2008.1
An expeditious room temperature synthesis of pyrazoles and diazepines by condensation of hydrazines/hydrazides and diamines with various 1,3-diketones is described. This greener protocol was catalyzed by polystyrene supported sulfonic acid (PSSA) and proceeded efficiently in water in the absence of any organic solvent within 1-2 min. (C) 2007 Elsevier Ltd. All rights reserved.
[Ce(<scp>l</scp>-Pro)<sub>2</sub>]<sub>2</sub> (Oxa) as a heterogeneous recyclable catalyst: synthesis of pyrazoles under mild reaction conditions
作者:Ramesh Katla、Rakhi Chowrasia、Padma S. Manjari、Caren D. G. da Silva、Beatriz F. dos Santos、Nelson L. C. Domingues
DOI:10.1039/c6nj01723a
日期:——
A highly efficient method for the synthesis of pyrazoles mediated by [Ce(l-Pro)2]2 (Oxa) as a heterogeneous catalyst.