Magnetic Fe<sub>3</sub>O<sub>4</sub>Nanoparticle-Supported Phosphotungstic Acid as a Recyclable Catalyst for the Kabachnik-Fields Reaction of Isatins, Imines, and Aldehydes under Solvent-Free Conditions
作者:Mohd Nazish、S. Saravanan、Noor-ul H. Khan、Prathibha Kumari、Rukhsana I. Kureshy、Sayed H. R. Abdi、Hari C. Bajaj
DOI:10.1002/cplu.201402191
日期:2014.9.22
reaction of isatins, imines, and aldehydes using dimethyl and diethylphosphite as a nucleophile to give the corresponding α‐hydroxy and α‐amino phosphonates in excellent yields for a wide range of substrates. The reaction conditions were simple, green, and efficient. The catalyst was recycled up to five times with retention of its activity. Based on the NMR spectroscopy studies, a probable catalytic cycle
Synthesis of α1-oxindole-α-hydroxyphosphonates under catalyst-free conditions using polyethylene glycol (PEG-400) as an efficient and recyclable reaction medium
A simple, efficient, eco-friendly, and cost-effective method has been developed for the synthesis of α1-oxindole-α-hydroxyphosphonate derivatives (3a–o) by a one-pot reaction of isatins (1a–o) with trialkyl phosphites (2a–o) under catalyst-free-conditions using inexpensive, non-toxic polyethyleneglycol (PEG-400) in excellent yields (82–92%). The present methodology offers an environmental acceptability;
Magnetic nanoparticle γ-Fe<sub>2</sub>O<sub>3</sub>-immobilized 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a highly recyclable and efficient nanocatalyst for the synthesis of α′-oxindole-α-hydroxyphosphonates
作者:Xiao Juan Yang
DOI:10.1002/aoc.3147
日期:2014.7
Magneticnanoparticle γ‐Fe2O3‐immobilized 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene as a novel magneticnanocatalyst was synthesized and characterized. The nanoparticle reagent catalyzed efficiently the synthesis of α′‐oxindole‐α‐hydroxyphosphonates from isatins and dimethyl phosphate under solvent‐free conditions at 60 °C. More importantly, the catalyst could be easily recovered by an external magnet and
alpha(1)-Oxindole-alpha-hydroxyphosphonates were synthesized for the first time in water under neutral conditions mediated by beta-cyclodextrin in high yields. The beta-cyclodextrin can be recovered and reused without any loss of activity. (C) 2010 Elsevier Ltd. All rights reserved.