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simple filtration and its direct efficient reuse in subsequent
reactions without significant loss of activity.
In summary, we have demonstrated that LiBr, a very
stable and mild reagent to handle, can efficiently cause
solvent-free transesterification of various esters at room
temperature. The conditions were successfully applied to
transacetylation and aminolysis of esters also. Recycling of
the catalyst and environmental safety of the process are
additional advantages of this method.
11. Zhou M-Y, Li Y-Q, Xu X-M (2003) Synth Commun 33:3777
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Experimental
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21:1161
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SP, Gaikwad AG (2007) J Mol Catal A Chem 276:158
19. Mino T, Hasegawa T, Shirae Y, Sakamoto M, Fujita T (2007)
J Organomet Chem 692:4389
IR spectra were recorded using KBr disks on a Bruker
Vector-22 infrared spectrometer. 1H NMR spectra were
obtained on a FT-NMR Bruker Ultra ShieldTM (500 MHz)
or Bruker AC 80 MHz instrument as CDCl3 solutions
using TMS as the internal standard reference. Mass spectra
were obtained on a Finnigan Mat 8430 apparatus. Starting
esters were prepared via Tishchenko dimerization of
aldehydes [33] or purchased from commercial sources.
´
20. Suarez-Castillo OR, Montiel-Ortega LA, Fragoso-Vazquez MJ,
Melendez-Rodrıguez M, Sanchez-Zavala M (2008) Tetrahedron
´
´
´
´
Lett 49:996
21. Santon MG, Gagne MR (1998) J Am Chem Soc 120:5981
Typical transesterification procedure
´
´
22. Kissling RB, Gagne MR (2000) Org Lett 2:4209
23. Majumdar AB, Singh B, Dutta D, Sadhukhan S, Gupta MN
(2006) Bioorg Med Chem Lett 16:4041
24. Singh M, Singh S, Singh RS, Chisti Y, Banerjee UC (2008)
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28. Gao L, Wu W, Hou Z, Jiang T, Han B, Liu J, Liu Z (2003) J Phys
Chem B 107:13093
29. Sarca VD, Laali KK (2004) Green Chem 6:245
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31. Mojtahedi MM, Abaee MS, Zahedi MM, Jalali MR, Mesbah AW,
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139:917
A suspension of an ester (10 mmol), an alcohol (30 mmol),
Et2NH (20 mol%, 2 mmol), and LiBr (10 mol%, 1 mmol)
was mixed at room temperature until TLC or GC experi-
ments showed completion of the reaction. LiBr was
separated by simple filtration and the ester product was
isolated from the filtrate by evaporation of the volatile
portion. The identity of the products was confirmed by
spectroscopic methods and comparison with published data
[11–13, 20, 27, 33, 36–38].
Typical aminolysis procedure
32. Abaee MS, Mojtahedi MM, Hamidi V, Mesbah AW, Massa W
(2008) Synthesis 2122
33. Mojtahedi MM, Akbarzadeh E, Sharifi R, Abaee MS (2007) Org
Lett 9:2791
34. Abaee MS, Sharifi R, Mojtahedi MM (2005) Org Lett 7:5895
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37. Islam N, Sopher DW, Utley JHP (1987) Tetrahedron 43:2741
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Catal 27:83
A suspension of an ester (10 mmol), an amine (13 mmol),
and LiBr (10 mol%, 1 mmol) was mixed at room temper-
ature until TLC or GC experiments showed completion of
the reaction. LiBr was separated by simple filtration and
the amide product was isolated from the filtrate by evap-
oration of the volatile portion. The identity of the products
was confirmed by spectroscopic methods and comparison
with published data [38, 42, 43, 45–50].
Acknowledgments Partial financial support by the Ministry of
Science, Research, and Technology of Iran is greatly appreciated.
40. Remme N, Koschek K, Schneider C (2007) Synlett 491
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