Microwave Assisted, Solvent Free One Pot Synthesis of Nitriles
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1
1
ν: 3094, 2230 cm .
convention; the H and 13C NMR spectra were refer-
o-nitrobenzonytril (2d) m.p. 109—110 ℃ (13)
(Lit.25 109 ℃); 1H NMR (CDCl3, 300 MHz) δ: 8.40 (d,
J=8.25 Hz, 1H, ArH), 7.85 (dd, J=8.0 Hz, 1H, ArH,),
7.82 (dd, J=7.85 Hz, 1H, ArH), 7.79 (dd, J=8.10 Hz,
enced to external SiMe4. Experiments were carried out
in closed vessel multi mode Microsynth Milstone labo-
ratory microwave oven (not domestic owen) using a 900
W Westpointe microwave operating at 3.67 GHz with
an internal volume of 0.9 m3. All experiments had good
reproducibility by repeating the experiments in same
conditions.
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1
1H, ArH); IR (KBr) ν: 3120, 2909, 2261 cm .
m-Nitrobenzonitrile (2e) m.p. 115—117 ℃ (Lit.26
1
115 ℃); H NMR (CDCl3, 300 MHz) δ: 8.46 (s, 1H,
H-Ar), 7.90 (d, J=9.0 Hz, 1H, H-Ar), 7.70 (dd, J=8.35,
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1
7.12 Hz, 1H, H-Ar); IR (KBr) ν: 3036, 2238 cm .
benzonitrile (2f) b.p. 189—190 ℃ (Lit.23 190
℃); 1H NMR (CDCl3, 300 MHz) δ: 7.55—7.61 (m, 5H,
Experimental
Benzaldehyde (2 mmol), hydroxylamine hydrochlo-
ride (4 mL), ammonium acetate (1 mL) and melamin
formaldehyde (2 g) were mixed thoroughly with me-
chanical mixer. This mixture was then irradiated in mi-
crowave oven (800 W). The progress of the reaction was
monitored with period of 30 s by TLC (EtOAC/CHCl3).
On the compellation of the reaction (monitored by TLC),
CHCl3 was added priory (10 mL×3). The formaldehyde
was removed by simple filtration and the organic layer
was separated. The solvent was removed by a rotary
evaporator and the resulting precipitate was washed with
CHCl3 (10 mL×2). The residue was then recrystallized
with ethanol and dried in electrical oven to give benzo-
nitryle in good to high yields (Table 1). For other
benazaldehyde derivatives, procedure was the same as
benzaldehyde.
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H-Ar); IR (liq) ν: 3031, 2232 cm .
p-Tolunitrile (2g) b.p. 216—218 ℃ (Lit.23 218
℃); 1H NMR (CDCl3, 300 MHz) δ: 7.23 (d, J=7.4 Hz,
2H, H-Ar), 7.47 (d, J=7.4 Hz, 2H, H-Ar); IR (KBr) ν:
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1
3039, 2229 cm .
2,4-dichlorobenzonitrile (2h) m.p. 58 —60 ℃
1
(Lit.23 61 ℃); H NMR (CDCl3, 300 MHz) δ: 7.54 (s,
J=8.0 Hz, 1H, H-Ar), 7.42 (d, J=7.95 Hz, 1H, H-Ar).
7.46 (d, J=8.0 Hz, 1H, H-Ar); IR (KBr) ν: 3076, 2234
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1
cm .
4-Chloro-3-nitrobenzonitrile (2i) m.p. 98—101
℃ (Lit.23 103 ℃); 1H NMR (CDCl3, 300 MHz) δ: 8.45
(s, J=8.0 Hz, 1H, H-Ar), 7.87 (d, J=8.23 Hz, 1H, H-Ar).
7.81 (d, J=8.15 Hz, 1H, H-Ar); IR (KBr) ν: 3076, 2234
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1
cm .
p-Dimethylaminobenzonitrile (2j) m.p. 69—71
1
℃ (Lit.27 75—77 ℃); H NMR (CDCl3, 300 MHz) δ:
Acknowledgment
3.02 (s, 6H, Me), 6.63 (d, J=8.2 Hz, 2H, H-Ar), 7.43 (d,
We gratefully thank the chemical research center of
Islamic Azad University, Firoozabad Branch for their
financial support of this work.
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1
J=8.2 Hz, 2H, H-Ar); IR (KBr) ν: 2909, 2261 cm .
Conclusion
References
It can be concluded that melamin formaldehyde/
hydroxylamine hydrochloride/ammonium acetate sup-
port, can be used as an efficient, excellent, readily
available, and cheap catalyst in conversion of aldehydes
to nitriles under microwave irradiation. Furthermore, the
reaction is a green process and the catalyst is recyclable
for several uses. The advantages of the present method
in terms of facile manipulation, fast reaction rates, and
formation of cleaner products under neat reaction condi-
tions should make this protocol as a valuable alternative
to the existing methods.
1
2
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(a) Cohen, M. A.; Sawden, J.; Turner, N. J. Tetrahedron
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Materials and method
Benzal-dehyde
derivatives,
NH2OH,
HCl,
NH+4 OAc , melamin formaldehyde (Merck) were
used without further purification. Silica gel Aldrich, 150
mesh (Aldrich) and TLC plates (Merck) were used.
Solvents were purified by standard methods. Infrared
spectra were recorded as KBr disks on a Shimadzu
model 420 spectrophotometer. The UV/Vis measure-
ments were made on a Uvicon model 922 spectrometer.
1H and 13C NMR were carried out on a Bruker
AVANCE DRX 300 spectrometer. All the chemical
shifts are quoted in δ using the high-frequency positive
5
6
Fabiani, M. E. Drug News Perspect 1999, 12, 207.
Chihiro, M.; Nagamoto, H.; Takemura, I.; Kitano, K.; Ko-
matsu, H.; Sekiguchi, K.; Tabusa, F.; Mori, T.; Tominnaga,
M.; Yabuuchi, Y. J. Med. Chem. 1995, 38, 353.
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