F. Amoroso et al. / Inorganica Chimica Acta 375 (2011) 256–262
261
(
2 ꢀ 1 mL). The solution was dried over Na
2
SO
4
and analysed by GC
bromobenzoyl chloride (0.72 g) in tetrahydrofurane (5 mL) until
pH 8 was reached. The reaction mixture was then stirred for 20 h
at room temperature. The resin was collected by filtration, washed
with water, methanol, and diethyl ether and dried under vacuum.
Yield: 2.16 g. Elemental analysis: C 64.39%, H 5.56%, N 2.22% (start-
ing aminomethyl–polystyrene resin: C 78.84%, H 6.96%, N 3.04%). A
sample of the product (270 mg) in ethanol (5 mL)/water (2 mL)
was stirred overnight at 80 °C in the presence of KOH (30 mg).
After cooling, the resin was washed with water, ethanol and
diethyl ether. Controls by IR spectra and weighting confirmed that
no hydrolysis occurred.
after purification on a microcolumn filled with silica gel or diato-
maceous earths, depending on the sample. Biphenyls 4–11 re-
ported in Table 3 are known products, and their identity has
been confirmed by GC-MS analysis.
0
0
CAS numbers of 4–11: 4-methyl-4 -nitro-1,1 -biphenyl (4)
2143-88-6); 1-(4-nitrophenyl)-naphtalene (5) (2765-23-3); 4-car-
(
0
0
0
bonitrile-4 -methyl-1,1 -biphenyl (6) (50670-50-3); 4-methoxy-4 -
nitro-1,1 -biphenyl (7) (2143-90-0); 4-carbonitrile-3 -acetyl-1,1 -
biphenyl (8) (371157-23-2); 4-methyl-1,1 -biphenyl (9) (644-08-
6
0
0
0
0
0
0
); 4-chloro-1,1 -biphenyl (10) (2051-62-9); 3-carbonitrile-4 -
0
methyl-1,1 -biphenyl (11) (893734-99-1).
The functionalyzed resin (176 mg) was added to a stirred solu-
tion of 4-methylphenylboronic acid (43 mg) in ethanol (1.5 mL)/
water (0.5 mL) in the presence of KOH (17 mg) and Pd wire 1
4
.3. Catalyst recycling
(
5.4 mg). The reaction mixture was stirred for 20 h at 80 °C. Then
In a thermostatted bath at 80 °C, a 10 mL Schlenk flask was
the resin was collected by filtration, washed with water, dichloro-
methane, and diethyl ether and dried under vacuum. Yield:
140 mg. Elemental analysis: C 74.58%, H 6.18%, N 1.53%.
charged in air with a magnetic stir bar, palladium wire (1)
5.4 mg), 1-naphtylboronic acid (0.6 mmol), KOH (0.6 mmol), etha-
nol (1.5 mL) and H O (0.5 mL), and the reaction was started upon
(
2
addition of 1-bromo-4-nitrobenzene (0.5 mmol). After 40 min,
the catalyst was removed by a pair of tweezers, washed with
water, ethanol, and dichloromethane, and finally dried on air. Then,
eight reuses of the catalyst were performed by applying the same
procedure. In the first six reuses, the yield of 1-(4-nitrophenyl)-
naphtalene (5) was quantitative. In the seventh reuse, the yield
dropped to 54%, while it increased to a maximum of 63% after
4.6. Thermal treatment of 1 and 2
A sample of Pd wire 1 of ca. 120 mg and one of Pd foil 2 of ca.
150 mg were introduced into a oven and treated on air at 900 °C
for 24 h. After cooling, both samples were analyzed by SEM and
then subjected to catalysis.
A sample of Pd wire 1 of ca. 100 mg was treated under a stream
3
h. In a further reuse, the maximum detected yield within 24 h
of H (5%)/N at 100 °C for 2 h. After cooling, the sample was ana-
2
2
was 29%.
lyzed by SEM and then subjected to catalysis.
4.4. Product yield/time measurements (Fig. 1)
Acknowledgements
A set of five different vessels into a bath thermostatted at 80 °C,
each containing 4-methylphenylboronic acid (0.6 mmol), KOH
0.6 mmol), catalyst 1 (5.4 mg), ethanol (1.5 mL), and water
0.5 mL), was prepared and the reactions were started at the same
time by addition of 1-bromo-4-nitrobenzene (0.5 mmol). From the
first vessel, two samples were extracted after 1 and 3 min, from the
second one after 5 and 8 min, from the third one after 10 and
This work was in part supported by a PRIN 2007 grant from the
Ministero dell’Istruzione e dell’Università (MIUR), Rome. The
authors thank Mr. M. Magnan (Dipartimento di Scienze e Tecnolo-
gie Chimiche, Università di Udine) for performing SEM
measurements.
(
(
References
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one after 45 and 60 min. Product yields measured by CG: 0.3%
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(
(
(
1 min); 3.6% (3 min); 10.4% (5 min); 31.7% (8 min); 66.7%
10 min); 82.2% (15 min); 90.2% (20 min); 96.0% (30 min); 97.3%
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[
[
[
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-Bromo-4-nitrobenzene (0.5 mmol), 1-naphtylboronic acid
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(
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(
[
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[
[
[
4.5.2. Hot filtration test
1
-Bromo-4-nitrobenzene (0.5 mmol), 4-methylphenylboronic
[
[
acid (0.6 mmol), KOH (0.6 mmol) and catalyst 2 (5.4 mg) were stir-
red at 80 °C in ethanol (1.5 mL)/water (0.5 mL) for 10 min. The
0
0
yield of 4-methyl-4 -nitro-1,1 -biphenyl was 33%, as inferred by
GC analysis. Immediately, the catalyst was removed by a pair of
tweezers and the reaction mixture was stirred for further 50 min.
GC monitoring showed that product yield increased to 89%.
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[
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4.5.3. Three-phase test
Triethylamine was added dropwise to a suspension of amino-
methyl-polystyrene resin (2 g, loading 1.1 mmol/g amine) and 4-
[