O.A. El-Khouly et al.
Bioorganic & Medicinal Chemistry 31 (2021) 115976
4
.1.8. (E)-2-(2-(1-(benzofuran-2-yl)ethylidene)hydrazineyl)-4-
= 6.9 Hz, 1H), 7.89 (d, J = 4.6 Hz, 1H), 7.76 (d, J = 8.3 Hz, 1H), 7.70 (d,
1
3
(
benzofuran-5-yl)thiazole (10)
J = 8.8 Hz, 2H), 7.55 (m, 2H), 7.46 (m, 1H), 7.39 (t, J = 7.5 Hz, 1H).
C
Brown solid, mp = 250–252 C, Yield = 75%. 1H NMR (400 MHz,
◦
NMR (100 MHz, DMSO‑d
): δ = 188.02, 178.79, 155.34, 150.68,
6
DMSO‑d
6
): δ = 7.69 (d, J = 7.5 Hz, 2H), 7.63 (t, J = 9.2 Hz, 2H), 7.42 (s,
141.01, 132.71, 130.52, 130.12, 129.81, 128.83, 127.54, 124.48,
+
1
H), 7.37 (s, 1H), 7.33 (d, J = 6.7 Hz, 2H), 7.28 (t, J = 7.2 Hz, 2H), 7.10
s, 1H), 3.99 (s, exchangeable H), 2.37 (s, 3H). 13C NMR (100 MHz,
DMSO‑d
124.39, 119.34, 117.75, 117.56, 112.52. MS m/z (%): 326.25 (M ,
+2
(
49.32), 328.26 (M , 19.91). Elemental analysis for C17H11ClN O ,
2 3
6
): δ = 170.31, 154.99, 154.53, 153.99, 153.64, 152.34, 139.33,
28.93, 128.54, 126.17, 125.99 125.18, 123.94, 122.12, 121.90,
11.71, 111.47, 107.51, 106.79, 102.72, 14.33. Elemental analysis for
S, calculated: C, 67.54; H, 4.05; N, 11.25; O, 8.57; S, 8.59.
Found: C, 67.34; H, 4.28; N, 11.57; O, 8.32; S, 8.67.
calculated: C, 62.49; H, 3.39; Cl, 10.85; N, 8.57; O, 14.69. Found: C,
62.27; H, 3.57; Cl, 10.77; N, 8.33; O, 14.57.
1
1
C
21
H
15
3
N O
2
4.1.14. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(4-methylphenyl)
diazenyl)acrylaldehyde (15)52
Dark brown solid, mp = 146–148 C, Yield = 75%. 1H NMR (400
◦
4
.1.9. (E)-2-(2-(1-(benzofuran-2-yl)ethylidene)hydrazineyl)-4-
MHz, DMSO‑d
6
): δ = 14.46 (s, exchangeable H), 9.97 (s, 1H), 7.92 (d, J
5
1
methylthiazole (11)
= 7.7 Hz, 1H), 7.89 (s, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.59 – 7.52 (m, 3H),
Brown solid, mp = 142–144 C, Yield = 65%. 1H NMR (400 MHz,
◦
7.39 (dd, J = 14.5, 7.2 Hz, 1H), 7.30 (d, J = 8.3 Hz, 2H), 2.33 (s, 3H).
NMR (100 MHz, DMSO‑d
13
C
DMSO‑d
6
): δ = 6.81 (d, J = 7.7 Hz, 1H), 6.74 – 6.69 (m, J = 9.4 Hz, 2H),
6
): δ = 187.82, 178.67, 155.25, 150.72,
6
.55 (t, J = 7.6 Hz, 1H), 6.45 (t, J = 7.6 Hz, 1H), 6.42 (s, 1H), 5.59 (s,
139.51, 136.57, 132.19, 130.73, 130.36, 128.72, 127.56, 124.41,
124.36, 117.69, 117.45, 116.23, 112.47, 21.06. Elemental analysis for
1
3
exchangeable H), 1.72 (s, 3H), 1.56 (s, 3H). C NMR (100 MHz,
DMSO‑d
): δ = 155.17, 153.31, 128.42, 126.52, 123.98, 122.33, 111.88,
08.69, 104.60, 15.25, 15.12, 8.88. Elemental analysis for C14 OS,
calculated: C, 61.97; H, 4.83; N, 15.49; O, 5.90; S, 11.82. Found: C,
6
18 14 2 3
C H N O , calculated: C, 70.58; H, 4.61; N, 9.15; O, 15.67. Found: C,
1
H
13
N
3
70.36; H, 4.83; N, 9.25; O, 15.47
6
1.77; H, 4.93; N, 15.59; O, 5.78; S, 11.96.
4.1.15. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(3-methylphenyl)
diazenyl)acrylaldehyde (16)
Light orange solid, mp = 115–117 C, Yield = 75%. 1H NMR (400
◦
4
1
.1.10. Synthesis of (E)-1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-
-one (12)
MHz, DMSO‑d
6
): δ = 14.38 (s, exchangeable H), 9.98 (s, 1H), 7.96 – 7.88
Dimethylformamide dimethylacetal (DMFDMA) (0.12 g, 1 mmol)
(m, 2H), 7.76 (d, J = 8.2 Hz, 1H), 7.56 (t, J = 7.6 Hz, 1H), 7.48 (d, J =
8.2 Hz, 2H), 7.43 – 7.33 (m, 2H), 7.10 (d, J = 7.3 Hz, 1H), 2.36 (s, 3H).
was added to solution of 2-acetyl benzofuran (2) (0.16 g, 1 mmol) in dry
xylene (30 ml) the reaction mixture was refluxed upon completion of the
reaction as judged by TLC. The mixture were concentrated under
reduced pressure. The formed solid was filtered off, recrystallized from
1
3
C NMR (100 MHz, DMSO‑d
6
): δ = 188.67, 178.53, 155.31, 150.56,
139.49, 133.28, 131.72, 128.83, 128.39, 127.57, 126.85, 126.61,
124.51, 124.39, 117.67, 115.82, 112.50, 16.84. Elemental analysis for
◦
xylene to give the pure product golden yellow solid. mp = 129–131 C,
18 14 2 3
C H N O , calculated: C, 70.58; H, 4.61; N, 9.15; O, 15.67. Found: C,
1
Yield = 90%. H NMR (400 MHz, DMSO‑d
6
): δ = 7.81 (d, J = 12.4 Hz,
70.36; H, 4.83; N, 9.25; O, 15.57.
1
H), 7.74 (d, J = 7.7 Hz, 1H), 7.66 (d, J = 8.3 Hz, 1H), 7.56 (s, 1H), 7.43
t, J = 7.5 Hz, 1H), 7.30 (t, J = 7.5 Hz, 1H), 5.85 (d, J = 12.4 Hz, 1H),
(
4.1.16. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(2-methylphenyl)
diazenyl)acrylaldehyde (17)
3
1
1
.17 (s, 3H), 2.94 (s, 3H). 13C NMR (100 MHz, DMSO‑d
6
): δ = 176.56,
Light orange solid, mp = 131–133 C, Yield = 75%. 1H NMR (400
◦
55.90, 154.84, 154.491, 128.04, 127.03, 123.91, 123.07, 112.29,
09.17, 91.47, 45.12, 37.70
MHz, DMSO‑d
6
): δ = 14.78 (s, exchangeable H), 10.02 (s, 1H), 7.97 (s,
1
H), 7.94 (d, J = 7.8 Hz, 1H), 7.82 – 7.74 (m, 2H), 7.57 (t, J = 7.4 Hz,
13
4
3
.1.11. General procedure for the preparation of (E)-3-(benzofuran-2-yl)-
-hydroxy-2-((E)- (substituted phenyl)diazenyl)acrylaldehyde compounds
1H), 7.45 – 7.34 (m, 3H), 7.23 (t, J = 7.3 Hz, 1H), 2.42 (s, 3H). C NMR
(100 MHz, DMSO‑d
): δ = 188.43, 178.88, 155.52, 150.61, 147.68,
147.57, 134.17, 129.09, 127.52, 126.08, 124.64, 124.49, 119.77,
118.34, 117.72, 115.60, 112.62. Elemental analysis for C18
6
(
13–18)
A cold solution of aryldiazonium chloride (1 mmol) was prepared by
adding a solution of NaNO (0.75 g, 20 mmol in 10 ml H O) to a cold
solution of appropriate aniline derivative (1 mmol) in concentrated HCl
5 ml) with stirring. The resulting solution of the aryldiazonium salt was
14 2 3
H N O ,
2
2
calculated: C, 70.58; H, 4.61; N, 9.15; O, 15.67. Found: C, 70.46; H,
4.83; N, 9.25; O, 15.57.
(
then added to a cold solution of Compound 16 in EtOH (50 ml) con-
taining sodium acetate (0.14 g, 1 mmol). The mixture was stirred at
room temperature for 1 h and the solid product formed was collected by
filtration and crystallized from ethanol.
4.1.17. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(4-nitrolphenyl)
diazenyl)acrylaldehyde (18)
Dark brown solid. mp = 220–222 C, Yield = 80%. 1H NMR (400
◦
MHz, DMSO‑d
6
): δ = 9.99 (s, exchangeable H), 9.65 (s, 1H), 8.34 (d, J =
9
.0 Hz, 1H), 8.27 (d, J = 9.0 Hz, 1H), 8.02 (s, 1H), 7.95 (d, J = 9.6 Hz,
4
.1.12. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(4-methoxyphenyl)
1H), 7.87 (d, J = 8.9 Hz, 2H), 7.80 (d, J = 8.2 Hz, 1H), 7.59 (d, J = 7.4
1
3
diazenyl)acrylaldehyde (13)
Hz, 1H), 7.41 (t, J = 7.3 Hz, 1H). C NMR (100 MHz, DMSO‑d ): δ =
6
Dark brown solid. mp = 137–139 C, Yield = 80%. 1H NMR (400
◦
188.43, 147.68, 144.42, 134.17, 130.41, 129.09, 127.52, 126.08,
124.64, 124.49, 119.77, 118.34, 117.72, 115.60, 112.93, 112.62.
MHz, DMSO‑d
6
): δ = 14.17 (s, exchangeable H), 9.98 (s, 1H), 7.91 (m,
2
7
H), 7.76 (d, J = 8.3 Hz, 1H), 7.62 – 7.52 (m, 1H), 7.48 – 7.33 (m, J =
11 3 5
Elemental analysis for C17H N O , calculated: C, 60.54; H, 3.29; N,
1
3
.4 Hz, 2H), 7.27 (s, 2H), 6.84 (m, 1H), 3.79 (s, 3H). C NMR (100 MHz,
): δ = 187.95, 163.62, 160.78, 155.30, 154.16, 153.09, 150.76,
43.34, 131.14, 130.39, 129.33, 128.15, 124.40, 117.59, 113.08,
12.78, 109.96, 102.57, 55.64. Elemental analysis for C18
12.46; O, 23.72. Found: C, 60.33; H, 3.47; N, 12.26; O, 23.96
DMSO‑d
6
1
1
4.1.18. Synthesis of 2-(benzofuran-2-yl)-1-(4-methylpiperazin-1-yl)
ethanethione (19)
14 2 4
H N O ,
calculated: C, 67.07; H, 4.38; N, 8.69; O, 19.86. Found: C, 67.25; H,
8
A mixture of 2-acetyl benzofuran (2) (0.16 g, 1 mmol) and S (10
4
.16; N, 8.87; O, 19.68.
2 3
mmol) was stirring in glycerol/K CO (10:1, 25 ml) for at 8 0˚C for 2 h.
The reaction mixture purred in ice/water then the product extracted by
ethyl acetate and purified with column chromatography (ethyl acetate:
petroleum ether, 2:1) to give compound 19.
4
.1.13. (E)-3-(benzofuran-2-yl)-3-hydroxy-2-((E)-(4-cholorophenyl)
diazenyl)acrylaldehyde (14)
Dark brown solid, mp = 165–167 C, Yield = 85%. 1H NMR (400
◦
Brown solid, mp = 119–121 C, Yield = 70%. 1H NMR (400 MHz,
◦
MHz, DMSO‑d
6
): δ = 14.26 (s, exchangeable H), 9.97 (s, 1H), 7.93 (d, J
CDCl
3
): δ = 7.93 (s, 1H), 7.89 (d, J = 7.8 Hz, 1H), 7.78 (d, J = 8.4 Hz,
1
5