Vol. 32, No. 4 (2020) Microwave-Assisted Synthesis of Imidazoles Containing Isoquinoline Scaffolds and their Antimicrobial Activity 841
2-(5-(5-(4-Bromophenyl)-2-(5-methoxy-2H-chromen-
126.3, 126.2, 124.1, 123.4, 122.6, 116.9, 115.5, 114.9, 107.9,
3
1
2
-yl)-1H-imidazol-1-yl)pentyl)-1H-benzo[de]isoquinoline-
101.4, 67.3, 55.6, 47.3, 39.9, 32.5, 30.6, 27.9, 24.5. MS, m/z:
+
,3(2H)-dione (8c): Pale yellow coloured solid; m.p.: 288-
found [M + H] 662; Calculated for C37
H: 4.89; Br:12.35; N: 6.45.
H
32
N
3
O Br: C: 67.15;
4
–1
90 °C; IR (KBr, νmax, cm ): 1658 (C=O), 1570 (N=C), 1112
1
(C-O-C); H NMR (CDCl
3
, 400 MHz): 8.57 (d, 2H, J = 7.2
2-(6-(5-(4-Chlorophenyl)-2-(5-methoxy-2H-chromen-
3-yl)-1H-imidazol-1-yl)hexyl)-1H-benzo[de]isoquinoline-
1,3(2H)-dione (8g): Pale yellow coloured solid; m.p.: 270-
Hz, Ar-H), 8.21 (d, 2H, J = 8.0 Hz, Ar-H), 7.76-7.72 (m, 2H,
Ar-H), 7.5 (d, 2H, J = 8.5 Hz, Ar-H), 7.46 (d, 1H, J = 8.5 Hz,
Ar-H), 7.11-7.01 (m, 2H, Ar-H), 6.52 (d, 2H, J = 8.2 Hz, Ar-
–1
272 °C; IR (KBr, νmax, cm ): 1656 (C=O), 1571 (N=C), 1116
1
H) 6.43 (d, 2H, J = 8.2 Hz, Ar-H), 5.20 (s, 2H, -OCH
.14 (m, 4H, -CH ), 3.82 (s, 3H, -OCH ), 2.00-1.53 (m, 6H,
); C NMR (CDCl , 100 MHz): 164.2, 155.7, 154.6,
2
), 4.24-
(C-O-C); H NMR (CDCl , 400 MHz): 8.59-8.54 (m, 2H, Ar-
3
4
2
3
H), 8.20-8.19 (m, 2H, Ar-H), 7.74-7.68 (m, 4H, Ar-H), 7.18
(s, 1H, Ar-H), 7.05-6.98 (m, 3H, Ar-H), 6.62 (s, 1H, Ar-H),
13
-
CH
2
3
1
1
1
44.2, 139.7, 134.0, 133.9, 133.0, 131.5, 131.2, 129.7, 128.1,
26.9, 126.4, 122.5, 120.8, 120.3, 117.8, 117.6, 111.8, 108.8,
6.43-6.41 (m, 2H, Ar-H), 5.18 (s, 2H, -OCH
4H, -CH ), 3.79 (s, 3H, -OCH ), 2.02-1.25 (m, 8H, -CH
NMR (CDCl , 100 MHz): 164.5, 155.9, 154.8, 144.4, 139.9,
2
), 4.22-4.08 (m,
13
2
3
2
); C
03.4, 66.4, 55.6, 47.4, 39.9, 30.4, 29.7, 26.7, 24.0. MS, m/z:
3
+
found [M + H] 648; Calculated for C36
H: 4.65; Br: 12.42; N: 6.52.
H
30
3 4
N O Br: C: 66.62;
134.2, 133.4, 131.4, 128.2, 128.1, 126.9, 126.7, 126.4, 122.5,
116.8, 115.5, 115.2, 107.9, 101.4, 67.0, 55.4, 47.4, 39.9, 32.3,
+
2
-(5-(2-(5-Methoxy-2H-chromen-3-yl)-5-(4-methoxy-
30.6, 27.5, 24.1. MS, m/z: found [M + H] 618; Calculated for
phenyl)-1H-imidazol-1-yl)pentyl)-1H-benzo[de]isoquino-
line-1,3(2H)-dione (8d): Pale yellow coloured solid; m.p.:
C
37
H
32
N
3
O
4
Cl: C: 71.95; H: 5.35; Cl: 5.95; N: 6.95.
2-(6-(2-(5-Methoxy-2H-chromen-3-yl)-5-(4-methoxy-
–1
2
1
7
2
8
62-264 °C; IR (KBr, νmax, cm ): 1658 (C=O), 1570 (N=C),
phenyl)-1H-imidazol-1-yl)hexyl)-1H-benzo[de]isoquino-
line-1,3(2H)-dione (8h): Pale yellow coloured solid; m.p.:
281-283 °C; IR (KBr, νmax, cm ): 1656 (C=O), 1576 (N=C),
1118 (C-O-C); H NMR (CDCl , 400 MHz): 8.59-8.55 (m,
2H, Ar-H), 8.20-8.18 (m, 2H, Ar-H), 7.74-7.68 (m, 3H, Ar-
H), 7.18 (s, 2H, Ar-H), 7.05-6.99 (m, 3H, Ar-H), 6.65 (s, 1H,
Ar-H), 6.43-6.41 (m, 2H, Ar-H), 5.17 (s, 2H, -OCH
4.09 (m, 4H, -CH ), 3.78 (s, 3H, -OCH ), 3.62 (s, 3H, -OCH
2.03-1.28 (m, 8H, -CH ); C NMR (CDCl , 100 MHz): 164.4,
155.9, 154.8, 144.5, 14.1, 139.7, 134.3, 133.1, 131.2, 128.4,
128.1, 126.8, 126.5, 126.5, 122.5, 116.7, 115.5, 115.3, 107.9,
101.4, 67.2, 55.5, 47.2, 39.7, 38.5, 32.3, 30.5, 27.5, 24.3. MS,
1
112 (C-O-C); H NMR (CDCl , 400 MHz): 8.59 (d, 2H, J =
3
–1
.2 Hz, Ar-H), 8.23 (d, 2H, J = 8.0 Hz, Ar-H), 7.76-7.72 (m,
H, Ar-H), 7.51 (d, 2H, J = 8.5 Hz, Ar-H), 7.48 (d, 1H, J =
.5 Hz, Ar-H), 7.11-7.01 (m, 2H, Ar-H), 6.53 (d, 2H, J = 8.2
1
3
Hz,Ar-H) 6.43 (d, 2H, J = 8.2 Hz,Ar-H), 5.21(s, 2H, -OCH
.25-4.14 (m, 4H, -CH ), 3.85 (s, 3H, -OCH ), 3.71 (s, 3H,
), 2.00-1.53 (m, 6H, -CH ); C NMR (CDCl , 100 MHz):
2
),
4
2
3
2
), 4.23-
13
-OCH
3
2
3
2
3
3
),
13
1
1
1
2
64.4, 155.9, 154.8, 144.6, 139.9, 134.4, 134.2, 133.1, 131.6,
31.4, 129.9, 128.3, 127.4, 126.3, 122.2, 120.9, 120.5, 118.4,
17.3, 112.4, 108.4, 103.9, 66.4, 55.8, 47.6, 40.9, 39.2, 30.2,
2
3
+
9.8, 27.7, 24.0. MS, m/z: found [M + H] 600; Calculated for
+
C
37
H
33
3 5
N O F: C: 74.22; H: 5.65; N: 7.15.
m/z: found [M + H] 614; Calculated for C38
H
35
N
3
O : C: 74.45;
5
2
-(6-(5-(4-Fluorophenyl)-2-(5-methoxy-2H-chromen-
H: 5.85; N: 6.92.
3
1
2
-yl)-1H-imidazol-1-yl)hexyl)-1H-benzo[de]isoquinoline-
,3(2H)-dione (8e): Pale yellow coloured solid; m.p.: 288-
Antibacterial activity: The antimicrobial activity of all the
synthesized compounds against Gram-positive bacterial strains
such as Bacillus subtilis and Staphylococcus and Gram-negative
strains such as Klebsiella pneumonia, Escherichia coli at a
various concentration of 10 µg/mL and 20 µg/mL. The cultures
were diluted with 5 % saline autoclaved and the ultimate volume
was made with concentration almost equal 10 –10 CFU/mL.
All the synthesized derivatives were dissolved in DMSO for
antimicrobial assays. For agar disc diffusion method, the solu-
tion form of tested compounds was saturated on the disc and
then allowed to air dry to get completely saturated with tested
compounds. These saturated discs were kept on the upper layer
of middle evenly flooded with the bacteria. The discs were
soaked in all compounds, were placed over the evenly extended
bacteria nutrient media and keep them warm at 37 °C for 2-3
days for enhanced inhibition of bacteria. After 24-48 h to
measure the zone of inhibition in mm. The zone of inhibition
of all the synthesized compounds 8a-h were compared with
the standard antibiotic as gatifloxacin at different concentration
(10 and 20 µg/mL).
–1
90 °C; IR (KBr, νmax, cm ): 1659 (C=O), 1572 (N=C), 1114
1
(
C-O-C); H NMR (CDCl
H), 8.20-8.18 (m, 2H, Ar-H), 7.74-7.68 (m, 4H, Ar-H), 7.19
s, 1H, Ar-H), 7.05-6.97 (m, 3H, Ar-H), 6.63 (s, 1H, Ar-H),
3
, 400 MHz): 8.59-8.55 (m, 2H, Ar-
(
5
6
6
4
.43-6.41 (m, 2H, Ar-H), 5.19 (s, 2H, -OCH
H, -CH ), 3.77 (s, 3H, -OCH ), 2.03-1.25 (m, 8H, -CH
, 100 MHz): 164.2, 155.7, 154.6, 144.2, 139.7,
2
), 4.22-4.09 (m,
13
2
3
2
); C
NMR (CDCl
3
1
1
6
34.0, 133.3, 132.2, 131.2, 130.2, 129.4, 128.2, 128.1, 127.1,
26.9, 126.5, 126.4, 122.5, 116.8, 115.4, 115.2, 107.7, 101.5,
7.0, 55.4, 47.2, 39.7, 32.3, 30.4, 27.5, 24.0. MS, m/z: found
+
[
M + H] 602; Calculated for C37
H
32
N
3
O F: C: 73.92; H: 5.45;
4
F: 3.24; N: 6.89.
2-(6-(5-(4-Bromophenyl)-2-(5-methoxy-2H-chromen-
3
1
2
-yl)-1H-imidazol-1-yl)hexyl)-1H-benzo[de]isoquinoline-
,3(2H)-dione (8f): Pale yellow coloured solid; m.p.: 277-
–1
79 °C; IR (KBr, νmax, cm ): 1657 (C=O), 1574 (N=C), 1115
1
(
C-O-C); H NMR (CDCl
H), 8.20-8.18 (m, 2H, Ar-H), 7.72-7.68 (m, 4H, Ar-H), 7.18
s, 1H, Ar-H), 7.05-6.96 (m, 3H, Ar-H), 6.65 (s, 1H, Ar-H),
3
, 400 MHz): 8.59-8.55 (m, 2H, Ar-
(
Antifungal activity: The screening of antifungal activity
of all the synthesized compounds 8a-h was tested three patho-
genic fungi such as Aspergillus niger, Fusarium oxysporum
and Aspergilus flavus. For asceptic condition of the poison
plate technique at a concentration of 100 µg/mL. three kinds
6
4
.45-6.41 (m, 2H, Ar-H), 5.21 (s, 2H, -OCH
H, -CH ), 3.79 (s, 3H, -OCH ), 2.04-1.25 (m, 8H, -CH
, 100 MHz): 164.4, 155.9, 154.8, 144.4, 139.9,
34.2, 133.5, 132.2, 131.4, 129.4, 128.5, 128.3, 128.0, 127.5,
2
), 4.24-4.09 (m,
13
2
3
2
); C
NMR (CDCl
1
3