CuO nanoparticles were recycled three times efficiently (first cycle 95%, third cycle
91%), with a catalyst recoverability of 95% in the first cycle and 81% in the third
cycle by simple centrifugation.
1. 1.26 mol% of CuO nanoparticles
2. 1 equiv. KOH, DMSO
3. 110 °C, air
4. 4 - 17 h
Amine
Yield
Benzylamine = 90%
Furfurylamine = 85%
n-Butylamine (80 °C) = 91%
Cyclohexylamine = 93%
Pyrrolidine = 93%
Morpholine = 89%
R
N
R
R
NH
R
R = H, aryl,
or cyclic
I
+
Scheme 5 Coupling of aryl amines with iodobenzene catalyzed by CuO nanoparticles
(1) 1.26 mol% of CuO nanoparticles
(2) 1 equiv. KOH, DMSO
110 °C, air
(3) 1.5 - 10 h
(4) Iodobenzene
R
Yield
p-Cl
= 92%
p-Br
= 83%
p-OMe = 94%
p-NO 2 = 70%
o-Me
= 96%
NH 2
R
H
N
R
1.25 equiv.
Scheme 4 Coupling of aryl amines with iodobenzene catalyzed by CuO nanoparticles
(1) 1.26 mol% of copper catalyst
(2) 1 equiv. KOH, DMSO, 110 °C,
air
(3) 2 - 10 h
X Catalyst
Yield
I CuSO 4
. 5H 2 O
= 46%
I Cu(OAc) 2
. H 2 O
= 33%
I CuO
= 35%
I CuO nanoparticles
= 95%
Br CuO nanoparticles
= 95%
Cl CuO nanoparticles
= 95%
1.2 equi
NH 2
X
+
HN
Scheme 3 Optimization studies using various copper catalysts
126
M.L. Kantam et al.