Ca(NO 3 ) 2 .4H 2 O + (NH 4 ) 2 HPO 4 +
C a 10 (PO 4 ) 6 (F) 2
Cu(OAc) 2
NH 4 F
CuFAP (1)
+
Scheme 6 Preparation of Catalyst CuFAP (1)
Table 5 N-Arylation of imidazole with chloro- and fluoroarenes
a
N-H
N
+
X=Cl, F
N
N
Ar
CuFAP
DMF, K 2 CO 3
120 °C
Ar-X
Entry
Ar–X
Time (h)
Yield (%)
b
1
1-Chloro-4-nitrobenzene
1
100 (90) 90
c
2
1-Chloro-2-nitrobenzene
3
100 (88)
3
4-Chlorobenzonitrile
6
98 (95)
4
2-Chloro-5-(trifluoromethyl) benzonitrile
3
100 (92)
5
4-Chlorobenzaldehyde
10
88 (82)
6
2-Chloropyridine
7
96 (92)
7
2-Chloropyrimidine
1
100 (90)
8
4-Chlorobenzophenone
6
96 (88)
9
Chlorobenzene
36
72 (60) 85
d
10
4-Chlorotoluene
36
65 (55)
11
4-Chloroanisole
36
62 (52)
12
2-Fluorobenzonitrile
1
95 (82)
13
4-Fluorobenzaldehyde
1
92 (80)
14
1-Fluoro-4-nitrobenzene
0.5
100 (85)
15
3-Chloro-4-fluoronitrobenzene
1
95 (85)
a
Aryl halide (1 mmol), imidazole (1.2 mmol), catalyst (100 mg), K 2 CO 3 (2 mmol), DMF (4 mL),
120
C
b
Yields refer to GC yields and yields in parentheses refer to isolated yields
c
GC yield after fourth recycle
d
GC yield obtained by using 10 mol% of KO
t Bu
Table 6 N-Arylation of imidazole with chloro- and fluoroarenes
a
O 2 N
X
+ Het-NH
K 2 CO 3 (2 eq)
DMF, 120 °C
O 2 N
N-Het
1.2 eq
1 eq
CuFAP (100 mg)
X = Cl, F
Entry
Het-NH
X¼Cl
X¼F
Time (h)
Yield (%)
a
Time (h)
Yield (%)
a
1
Pyrrole
4
90 (80)
2
95 (85)
2
Pyrazole
3
95 (85)
1
90 (80)
3
Benzimidazole
12
85 (72)
9
85 (75)
4
Piperidine
5
90 (80)
1
95 (85)
a
Yields refer to GC yields and yields in parenthesis refer to isolated yields
Recent Developments in Recyclable Copper Catalyst Systems for C–N Bond. . .
129