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B. Baruwati et al. / Tetrahedron Letters 50 (2009) 1215–1218
4.1. Synthesis of the catalyst
characterizing with GCMS. The catalyst was then washed with ace-
tone, dried at 80 °C in an oven for 15 minutes, and reused.
NiFe2O4 nanoparticles were synthesized via hydrothermal route
at 250 °C using Fe(NO3)3 Á 9H2O and, Ni(NO3)2 Á 6H2O as the precur-
sors. The pH of the reaction mixture was maintained at 9 by addi-
tion of ammonium hydroxide solution. The as-synthesized
particles were highly magnetic in nature. Two grams of the as-syn-
thesized particles were then dispersed in 100 mL of deionized
water by sonication for 15 min. Three grams of dopamine hydro-
chloride were then added refluxed overnight under magnetic stir-
ring. The particles were then separated by applying a magnetic bar
at the bottom of the reaction vessel, washed several times with
ethanol, and dried under vacuum at 45 °C. The dopamine-modified
particles were then dispersed in 100 mL of water. The particles
were observed to be highly dispersed in water after modification
with dopamine. 0.095 g of ruthenium(III)chloride was then added
to the solution, and pH was maintained at 9 by addition of sodium
borohydride. The reaction mixture was kept under magnetic stir-
ring overnight. The final particles were separated from the solution
by applying a magnetic field, washed three times with water to re-
move any chloride ions present, and dried under vacuum.
Acknowledgments
Babita Baruwati and Vivek Polshettiwar were supported by the
Postgraduate Research Program at the National Risk management
Research Laboratory administered by the Oak Ridge Institute for
Science and Education through an interagency agreement between
the U.S. Department of Energy and the U.S. Environmental Protec-
tion Agency.
References and notes
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4.3. Transfer hydrogenation of carbonyl compounds
In a typical reaction, 1 mmol of the substrate was added to
5.0 mL of isopropyl alcohol in a 10 mL microwave tube. Catalyst
(0.1 g) and 0.1 mmol (0.056 g) of potassium hydroxide were added.
The reaction mixture was then subjected to MW irradiation in a
CEM Discover MW system for 30–45 min at 100 °C. After the
reaction was completed, the reaction vessel was kept undisturbed
for 5 min, wherein the catalyst adhered to the magnetic bar. The
reaction mixture was collected by decantation and washed with
water; the product was extracted by dichloromethane before