(TEM) studies of both fresh and used catalysts were carried out to determine the
shape and size of the particles. Interestingly, it is observed that the shape and size of
the particles remain unchanged. This confirms that the morphology of the catalyst
remains same even after recycling.
Table 12 N-Arylation of imidazole using different fluoroarenes
a
1. 91% (0.5 h), 0
b
2. 89% (2 h)
3. 85% (2 h)
4. 83% (1 h)
5. 91% (1.5 h)
6. 83% (2 h)
7. 87% (3 h)
9. 94% (2 h)
CN
8. 87% (1.5 h)
O
N
N
O 2 N
N
NO 2
N
NC
N
N
OHC
O
N
N
NC
N
Cl
OHC
Cl
N
N
N
N
N
N
N
N
N
DMF, K 2 CO 3
+
N
H
N
N
N
Nano-CuO, 120 °C
FG
F
FG
a
Reaction conditions: Ar–F (1 mmol), imidazole (1.2 mmol), nano-CuO (10 mol%), K 2 CO 3
(2 mmol), DMF (4 mL), isolated yields; reaction times are in parenthesis
b
Yield without catalyst
Table 13 N-Arylation of indole with different chloroarenes
a
1. 89% (9)
N
O 2 N
N
NC
N
CN
N
N
N
N
N
N
2. 76% (18)
3. 83% (18)
4. 94% (1.5)
5. 77% (23)
+
N
H
N
Nano-CuO, 120 °C
DMF, K 2 CO 3
FG
Cl
FG
a Reaction conditions: Ar–Cl (1 mmol), indole (1.2 mmol), nano-CuO (10 mol%), K 2 CO 3
(2 mmol), DMF (4 mL). Isolated yields, reactions times are in hours
Recent Developments in Recyclable Copper Catalyst Systems for C–N Bond. . .
137