An Efficient Recyclable Polymer
1173
(1.2 mmol), K2CO3 (2 mmol), and 10 mL DMSO were
stirred under nitrogen atmosphere, at 100 °C. The reaction
mixtures were collected at different time interval and
identified by GCMS and quantified by GC analysis. After
the completion of the reaction, the catalyst was filtered off
and washed with water followed by acetone and dried in
oven. The filtrate was extracted with ethyl acetate
(3 9 20 mL) and the combined organic layers were dried
with anhydrous Na2SO4 by vacuum. The filtrate was con-
centrated by vacuum and the resulting residue was purified
by column chromatography on silica gel to provide the
desired product.
3H), 7.28 (bs, 1H), 7.21 (bs, 1H); 13C NMR (100 MHz,
CDCl3) d 136.1, 134.5, 130.1, 129.3, 127.4, 121.3, 118.2.
1-(4-Methylphenyl)-1H-imidazole (B) [26]: 1H NMR
(400 MHz, CDCl3) d 7.76 (s, 1H), 7.24 (m, 4H), 7.19 (bs,
1H), 7.13 (bs, 1H), 2.39 (s, 3H); 13C NMR (100 MHz,
CDCl3) d 137.4, 135.5, 134.8, 130.3, 130.0, 121.3, 118.3,
20.90.
1
1-(4-Methoxyphenyl)-1H-imidazole (C) [27]: H NMR
(400 MHz, CDCl3)
d 7.71 (s, 1H), 7.28 (d, 2H,
J = 9.0 Hz), 7.15 (bs, 1H), 7.11 (bs, 1H), 6.94 (d,
J = 9.0 Hz, 2H), 3.83 (s, 3H); 13C NMR (100 MHz,
CDCl3) d 159.0, 135.8, 130, 130.8, 123 (2C), 118.5, 114.6,
(2C), 55.2.
2.4 General Procedure for N-Arylation of N–H
Heterocycles with Arylboronic Acids
1-(4-(1H-Imidazol-1-yl)phenyl)ethanone(D) [26]: 1H
NMR (400 MHz, CDCl3) d 8.08 (d, 2H), 7.95 (bs, 1H),
7.49 (d,2H), 7.35 (bs, 1H), 7.24 (bs, 1H), 2.63 (s, 3H);13C
NMR (100 MHz, CDCl3) d 196.4, 140.7, 135.7, 135.4,
131.0,130.3, 120.6, 117.7, 26.5.
In a 100 mL RB flask, Cu-PAR (0.05 g, 0.0129 mmol),
arylboronic acid (1 mmol), N–H heterocycles (1.2 mmol),
and 10 mL methanol were stirred under nitrogen atmo-
sphere, at 40 °C. The reaction mixtures were collected at
different time interval and identified by GCMS and quan-
tified by GC analysis. After the completion of the reaction,
the catalyst was filtered off and washed with water fol-
lowed by acetone and dried in oven. The filtrate was
extracted with ethyl acetate (3 9 20 mL) and the com-
bined organic layers were dried with anhydrous Na2SO4 by
vacuum. The filtrate was concentrated by vacuum and the
resulting residue was purified by column chromatography
on silica gel to provide the desired product.
1-(4-Nitrophenyl)-1H-imidazole(E) [26]: 1H NMR
(400 MHz, CDCl3) d 8.39 (d, 2H), 7.99 (bs, 1H), 7.58 (d,
2H), 7.38 (bs, 1H), 7.28 (bs, 1H); 13C NMR (100 MHz,
CDCl3) d 146.3, 141.9, 135.4, 131.7, 125.7, 121.0, 117.6.
1
1-o-Tolyl-1H-imidazole (F) [26]: H NMR (400 MHz,
CDCl3) d 7.59 (bs, 1H), 7.34–7.27 (m, 3H), 7.23–7.20 (m,
2H), 7.06 (bs, 1H), 2.18 (s, 3H); 13C NMR (100 MHz,
CDCl3) d 137.4, 136.5, 133.8, 131.2, 129.2,128.7, 126.8,
126.4, 120.4, 17.5.
1-phenyl-1H-benzimidazole (G) [23]: 1H NMR
(400 MHz, CDCl3) d 8.07 (s, 1H), 7.82–7.86 (m, 1H),
7.44–7.60 (m, 6H), 7.5–7.3 (m, 2H); 13C NMR (100 MHz,
CDCl3) d 143, 142.5, 136.7, 133.6, 130, 127.8, 126, 123.8,
122.9(2C), 120.3, 110.1, (2C).
1-Phenyl-1H-pyrazole (H) [28]: 1H NMR (400 MHz,
CDCl3) d 7.88 (bs, 1H), 7.68–7.63 (m, 3H), 7.43 (t, 2H),
7.23 (m, 1H), 6.42 (bs, 1H); 13C NMR (100 MHz, CDCl3)
d 140.7, 140.0, 129.1, 126.7, 126.4, 119.0, 107.5.
1-Phenyl-1H-pyrrole (I) [28]: 1H NMR (400 MHz,
CDCl3) d 7.46–4.42 (m, 4H), 7.32–7.25 (m, 1H), 7.11 (s,
2H), 6.39 (s, 2H); 13C NMR (100 MHz, CDCl3) d 141.0,
129.8, 126.0, 121.3, 117.3, 111.2.
1-(3,4-dimethoxyphenyl)-1H-imidazole (J) [23]: 1H
NMR (400 MHz, CDCl3) d 7.78 (s, 1H), 7.13 (br s, 1H),
7.10 (br s, 1H), 6.86 (br s, 2H), 6.85 (br s, 1H), 3.92 (s, 6H).
1-(4-Chlorophenyl)-1H-imidazole (K) [26]: 1H NMR
(400 MHz, CDCl3) d 7.85 (bs, 1H), 7.46–7.42 (m, 2H),
7.35–7.26 (m, 4H); 13C NMR (100 MHz, CDCl3) d 135.7,
133.0, 131.9, 130.5, 129.9, 122.6, 118.1.
2.5 General Procedure for Amination of Aromatic
Amines with Arylboronic Acids
In an oven dried 100 mL RB flask, Cu-PAR (0.05 g,
0.0129 mmol), arylboronic acid (1.5 mmol), aromatic
amines (1.2 mmol), KOH (1 mmol), and 10 mL DMSO
were stirred under nitrogen atmosphere, at 120 °C. The
reaction mixtures were collected at different time interval
and identified by GCMS and quantified by GC analysis.
After the completion of the reaction, the catalyst was fil-
tered off and washed with water followed by acetone and
dried in oven. The filtrate was extracted with ethyl acetate
(3 9 20 mL) and the combined organic layers were dried
with anhydrous Na2SO4 by vacuum. The filtrate was con-
centrated by vacuum and the resulting residue was purified
by column chromatography on silica gel to provide the
desired product.
1-(3-nitrophenyl)-1H-imidazole (L) [27]: 1H NMR
(400 MHz, CDCl3) d 8.36 (s, 1H), 8.24–8.02 (m, 2H), 7.91
(d, J = 9.4 Hz, 1H), 7.74 (t, J = 8.6 1H), 7.52 (br s, 1H),
7.18 (br s, 1 H).
1-(4-Fluorophenyl)-1H-imidazole (M) [23]: 1H NMR
(400 MHz, CDCl3) d 7.76 (br s, 1H), 7.33–7.37 (m, 2H),
2.6 Spectral Data of all Products
1-Phenyl-1H-imidazole (A) [26]: 1H NMR (400 MHz,
CDCl3) d 7.85 (s, 1H), 7.53–7.44 (m, 2H), 7.42–7.35 (m,
123