Sulfated polyborate catalyzed Kindler reaction: a rapid, efficient, and green protocol
room temperature and quenched with 5 cm3 water. Solid
was filtered at vacuum pump, washed with water
(3 9 5 cm3), dried under vacuum to get the products in
pure form or recrystallized from ethanol. The products
obtained were known compounds and were identified by
melting point, FT-IR, and 1H NMR spectroscopy. The
spectral data were compared with those in the literature.
Acknowledgements The authors are grateful to University Grants
Commission, New Delhi, India for their financial supports.
References
Fig. 2 Recyclability of the catalyst
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Melting points of all the compounds were recorded by
Analab ThermoCal melting point apparatus in the open
capillary tube. The FT-IR spectra (KBr) were recorded on
Shimadzu FTIR Affinity-1 Fourier Transform Infrared
spectrophotometer. 1H NMR spectra were recorded on
MR400 Agilent Technology NMR spectrometer using
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DMSO-d6 or CDCl3 as a solvent. Chemicals and solvents
used were of LR grade and purchased from SD fine, Avra
Synthesis, and Spectrochem and used without purification.
The purity determination of the starting materials and
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To a mixture of an aldehyde (2 mmol), amine (2.4 mmol),
and sulfur (2.4 mmol) was added sulfated polyborate
(10 wt%). The mixture was heated at 100 °C in an oil bath.
The reaction was monitored by thin layer chromatography.
After completion of the reaction, the mixture was cooled to
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