Medicinal Chemistry Research
(M + 1); Anal. for C18H15N3O2: calcd: C 70.81, H 4.95, N
13.76, found: C 70.94, H 5.18, N 13.48.
N′-(1-(4-nitrophenyl)ethylidene)-5-phenylisoxazole-3-
carbohydrazide (5e)
N′-(1-(4-bromophenyl)ethylidene)-5-phenylisoxazole-3-
Pale yellow crystalline (56.5%); Rf = 0.54; m.p.: 247–248 °C;
1H NMR (300 MHz, DMSO-d6): δ = 2.50 (s, 3H, CH3),
7.38–7.59 (m, 4H, 3Ar-H, isoxazole CH), 7.97–7.98 (m, 2H,
Ar-H), 8.12–8.19 (m, 2H, Ar-H), 8.30–8.32 (m, 2H, Ar-H),
11.30 (s, 1H, CONH); 13C NMR (75 MHz, DMSO-d6): δ =
18.88 (CH3), 101.76 (isoxazole CH), 123.26 (2C), 126.15
(2C), 127.67 (2C), 128.09, 128.69 (2C), 130.34, 141.08,
148.52, 149.18, 160.54, 162.39, 170.81; IR (KBr): 3345.67
(NH), 3077.56 (Ar C-H), 1698.40 (NH-C=O), 1558.55
(C=N), 1516.11 (C=C, isoxazole), 1492.00 (Ar N-O),
1448.60 (Ar C=C), 1346.37 cm−1 (Ar N-O); ESI-MS (m/z):
351.53 (M + 1); Anal. for C18H14N4O4: calcd: C 61.71, H
4.03, N 15.99, found: C 62.01, H 4.34, N 16.24.
carbohydrazide (5b)
White shiny needle-shaped crystalline (48.0%); Rf = 0.68;
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m.p.: 214–215 °C; H NMR (400 MHz, CDCl3): δ = 2.39
(s, 3H, CH3), 7.42 (s, 1H, isoxazole CH), 7.54–7.61 (m, 5H,
Ar-H), 7.80–7.82 (m, 2H, Ar-H), 7.93–7.95 (m, 2H, Ar-H),
11.03 (s, 1H, CONH). 13C NMR (100 MHz, CDCl3):: δ =
14.37 (CH3), 99.99 (isoxazole CH), 123.42, 125.68 (2C),
126.23, 128.42 (2C), 129.10 (2C), 130.65, 131.19, 136.71
(2C), 155.50, 155.79, 158.77, 170.41; IR (KBr): ṽ =
3287.81 (NH), 3055.38 (Ar C-H), 1680.07 (NH-C=O),
1546.01 (C=N), 1485.25 (C=C, isoxazole), 1444.75 cm−1
(Ar C=C); ESI-MS (m/z): 385.30 (M + 1), 386.28 (M + 2);
Anal. for C18H14BrN3O2: calcd: C 56.27, H 3.67, N 10.94,
found: C 56.49, H 3.75, N 10.68.
N′-(1-(4-methoxyphenyl)ethylidene)-5-phenylisoxazole-3-
carbohydrazide (5f)
N′-(1-(4-hydroxyphenyl)ethylidene)-5-phenylisoxazole-3-
carbohydrazide (5c)
White shiny needle-shaped crystalline (81.8%); Rf = 0.64;
m.p.: 201–203 °C; H NMR (300 MHz, CDCl3): δ = 2.29
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(s, 3H, CH3), 3.76 (s, 3H, OCH3), 6.83–6.85 (m, 2H, Ar-H),
7.02 (s, 1H, isoxazole CH), 7.38–7.43 (m, 3H, Ar-H),
7.77–7.78 (m, 4H, Ar-H), 9.56 (s, 1H, CONH). 13C NMR
(75 MHz, CDCl3): δ = 13.26 (CH3), 55.36 (OCH3) 99.52
(isoxazole CH), 113.80 (2C), 125.97 (2C), 126.61, 128.39
(2C), 129.19 (2C), 129.89, 130.89, 153.86, 154.79, 158.68,
161.22, 171.84; IR (KBr): 3360.14 (NH), 3000.40 (Ar C-
H), 1695.50 (NH-C=O), 1539.26 (C=N), 1507.43 (C=C,
isoxazole), 1446.67 cm−1 (Ar C=C). ESI-MS (m/z): 336.42
(M + 1); Anal. for C19H17N3O3: calcd: C 68.05, H 5.11, N
12.53, found: C 68.37, H 5.43, N 12.78.
Buff colored crystalline (85.7%); Rf = 0.52; m.p.:
235–236 °C; H NMR (300 MHz. DMSO-d6): δ = 2.31 (s,
3H, CH3), 6.82–6.84 (m, 2H, Ar-H), 7.49–7.58 (m, 5H, 4
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Ar-H, isoxazole CH), 7.73–7.75 (m, 2H, Ar-H), 7.96–7.98
(m, 1H, Ar-H), 9.90 (s, 1H, CONH), 10.99 (s, 1H, OH); 13
C
NMR (75 MHz. DMSO-d6): δ = 14.92 (CH3), 100.68
(isoxazole CH), 115.62 (2C), 126.28 (2C), 126.73, 128.18,
128.80 (2C), 129.86 (2C), 131.40, 155.74, 158.61, 159.64,
159.76, 170.76; IR (KBr): 3342.78 (OH), 3297.45 (NH),
3071.77 (Ar C-H), 1676.21 (NH-C=O), 1540.23 (C=N),
1514.19 (C=C, isoxazole), 1448.60 cm−1 (Ar C=C); ESI-
MS (m/z): 322.40 (M + 1); Anal. for C18H15N3O3: calcd: C
67.28, H 4.71, N 13.08, found: C 67.45, H 5.04, N 12.71.
N′-(1-(3,4-dimethoxyphenyl)ethylidene)-5-phenylisoxazole-
3-carbohydrazide (5g)
5-phenyl-N′-(1-(p-tolyl)ethylidene)isoxazole-3-
carbohydrazide (5d)
White shiny needle-shaped crystalline (64.6%): Rf = 0.68;
m.p.: 168–169 °C; H NMR (300 MHz, CDCl3): δ = 2.38
1
(s, 3H, CH3), 3.91 (s, 3H, OCH3), 3.97 (s, 3H, OCH3),
6.86 (d, 1H, Ar-H, J = 5.1 Hz), 7.27 (s, 1H, isoxazole CH),
7.33 (dd, 1H, Ar-H, J = 1.2 Hz, 1.2 Hz), 7.46–7.50 (m,
3H, Ar-H), 7.60 (d, 1H, Ar-H, J = 1.2 Hz) 7.80–7.82 (m,
2H, Ar-H), 9.66 (s, 1H, CONH). 13C NMR (75 MHz,
CDCl3): δ = 13.31 (CH3), 55.99 (OCH3), 56.06 (OCH3),
99.46 (isoxazole CH), 109.31, 110.32, 120.25, 125.98
(2C), 126.58, 129.19 (2C), 130.20, 130.91, 148.99,
150.99, 153.97, 154.78, 158.64, 171.88; IR (KBr):
3319.63 (NH), 2999.44 (Ar C-H), 1684.89 (NH-C=O),
1595.51 (C=N), 1517.08 (C=C, isoxazole), 1442.82 cm−1
(Ar C=C); ESI-MS (m/z): 366.28 (M + 1); Anal. for
C20H19N3O4: calcd: C 65.74, H 5.24, N 11.50, found: C
65.93, H 5.58, N 11.18.
White shine crystalline (77.6%); Rf = 0.80; m.p.: 197–198 °C;
1H NMR (300 MHz, CDCl3): δ = 2.37–2.42 (m, 6H, 2
CH3), 7.10 (s, 1H, isoxazole CH), 7.20–7.22 (m, 1H, Ar-H),
7.35–7.50 (m, 4H, Ar-H), 7.73–7.79 (m, 4H, Ar-H), 9.67 (s,
1H, CONH). 13C NMR (75 MHz, CDCl3): δ = 13.33 (CH3),
21.34 (Ar-CH3) 99.51 (isoxazole CH), 125.96 (2C), 126.39,
126.58, 126.77 (2C), 129.19 (2C), 130.44, 130.88, 134.56,
140.27, 154.11, 154.83, 158.63, 171.85; IR (KBr): 3364.96
(NH), 3065.02 (Ar C-H), 1698.40 (NH-C=O), 1570.12
(C=N), 1511.29 (C=C, isoxazole), 1446.67 cm−1 (Ar
C=C); ESI-MS (m/z): 320.42 (M + 1), Anal. for
C19H17N3O2: calcd: C 71.46, H 5.37, N 13.16, found: C
71.88, H 5.64, N 12.88.