Med Chem Res
signals for minor E-imine isomer anti-amide bond rotamer
δ = 11.944 (bs, 1H, NH) ppm; 13C-NMR (DMSO-d6, 150
MHz): δ = 113.15 (C-4a), 112.22 (C-4′), 115.51 (C-3′),
116.60 (C-8), 122.93 (C-3), 125.37 (C-6), 126.12 (C-5),
133.84 (C-7), 141.56 (C-9), 146.31 (C-5′), 146.78 (C-2′),
151.34 (C-4), 153.17 (C-8a), 158.52 (C-2), 159.08 (C-10)
ppm; HRESIMS m/z: found [M + H]+ 317.03236 (calcd.
[M + H]+ 317.03236).
1576; 1H NMR (DMSO-d6, 600 MHz, ppm) 1:0.12 mixture
of conformers; signals for major E-imine isomer syn-amide
rotamer δ = 5.034 (s, 2H, H-2), 6.670 (dd, J = 1.7, 3.5 Hz,
1H, H-4′); 6.826 (d, J = 8.3 Hz, 1H, H-8), 6.922 (dt, J =
1.0, 7.4 Hz, 1H, H-6), 6.929 (s, 1H, H-4), 7.184 (dt, J = 1.6,
8.3 Hz, 1H, H-7), 7.192 (d, J = 7.4 Hz, 1H, H-5), 7.257 (d,
J = 3.0 Hz, 1H, H-3′), 7.856 (bs, 1H, H-5′), 8.110 (s, 1H, H-
9), 11.959 (s, 1H, NH); resolved signals for minor E-imine
isomer anti-amide bond rotamer δ = 11.58 (s, 1H, NH);
13C-NMR (DMSO-d6, 150 MHz, ppm) δ = 64.33 (C-2),
112.88 (C-4′), 116.11 (C-3′), 116.21 (C-8), 122.29 (C-4a),
122.44 (C-6), 128.47 (C-7), 129.50 (C-3), 129.74 (C-4),
131.26 (C-5), 146.62 (C-2′), 146.66 (C-9), 146.62 (C-5′),
154.61 (C-8a), 155.11 (C-10); HRESIMS m/z: found
269.09198[M + H]+ (calcd. 269.092069 [M + H]+).
N′-[(E)-(4-chloro-2-oxo-2H-chromen-3-yl)methylidene]-4-
methoxybenzohydrazide (4c)
Yellow crystals, yield: 0.200 g, 30%; m.p. 229–230 °C.
1
FTIR (ATR) νmax 3200, 3031, 1716, 1651, 1602 cm−1; H
NMR (DMSO-d6, 600 MHz) 1:0.19 mixture of conformers;
signals for major E-imine isomer syn-amide rotamer δ =
3.841 (s, 3H, OCH3), 7.076 (bd, J = 7.0 Hz, 2H, H-3′ and
H-5′), 7.497 (t, J = 7.3 Hz, 1H, H-6),7.513 (d, J = 7.8 Hz,
1H, H-8), 7.756 (t, J = 7.7 Hz, 1H, H-7), 7.9552 (bd, J =
7.1 Hz, 2H, H-2′ and H-6′), 8.030 (d, J = 7.9 Hz, 1H, H-5),
8.630 (bs, 1H, C-9), 12.033 (bs, 1H, NH); resolved signals
for minor E-imine isomer anti-amide bond rotamer δ =
11.89 (bs, 1H, NH) ppm; 13C-NMR (DMSO-d6, 150 MHz):
δ = 55.49 (OCH3), 113.84 (C-3′ and C-5′), 116.60 (C-8),
118.43 (C-4a), 125.12 (C-1′), 125.37 (C-6), 126.09 (C-5),
129.78 (C-2′ and C-6′), 133.64 (C-7), 135.52 (C-4), 140.87
(C-9), 151.29 (C-8a), 157.77 (C-2), 162.29 (C-4′), 162.53
(C-10) ppm; HRESIMS m/z: found [M + H]+ 357.06357
(calcd. [M + H]+ 357.06366).
N′-[(E)-2H-Chromen-3-ylmethylidene]-4-
methoxybenzohydrazide (8c)
Yellow crystals, yield 62%, 0.382 g; m.p. 204–206 °C;
FTIR (ATR) cm−1 3219, 3070, 2836, 1632, 1602, 1580; 1H
NMR (DMSO-d6, 600 MHz, ppm) δ = 3.790 (s, 3H,
CH3O), 5.051 (s, 2H, H-2), 6.823 (d, J = 8.1 Hz, 1H, H-8),
6.910 (s, 1H, H-4), 6.930 (dt, J = 0.9, 7.5 Hz, 1H, H-6),
7.025 (d, J = 8.8 Hz, 2H, H-3′ and H-5′), 7.16–7.19 (m, 2H,
H-7 and H-5), 7.840 (d, J = 8.8 Hz, 2H, H-2′ and H-6′),
8.104 (s, 1H, H-9), 11.986 (s, 1H, NH); 13C-NMR (DMSO-
d6, 150 MHz, ppm) δ = 56.00 (CH3O), 64.40 (C-2), 114.42
(C-3′ and C-5′), 116.19 (C-8), 122.36 (C-4a), 122.41 (C-6),
125.42 (C-1′), 128.39 (C-5), 129.28 (C-4), 129.69 (C-3),
130.18 (C-2′ and C-6′), 131.14 (C-7), 146.81 (C-9), 154.58
(C-8a), 162.75 (C-4′), 163.70 (C-10); HRESIMS m/z: found
309.12335 [M + H]+ (calcd. 309.123369 [M + H]+).
4-Chloro-N′-[(E)-2H-chromen-3-ylmethylidene]
benzohydrazide (8a)
Yellow crystals, yield 68%, 0.424 g; m.p. 190–192 °C;
FTIR (ATR) cm−1 3378, 3195, 3031, 1653, 1623, 1592,
N′-[(E)-2H-Chromen-3-ylmethylidene]thiophene-2-
carbohydrazide (8d)
1565 cm−1 1H NMR (DMSO-d6, 600 MHz, ppm) δ =
;
5.055 (s, 2H, H-2), 6.835 (d, J = 8.3 Hz, 1H, H-8), 6.929
(dt, J = 0.9, 7.4 Hz, 1H, H-6), 6.955 (s, 1H,H-4), 7.18–7.21
(m, 2H, H-7 and H-5), 7.569 (d, J = 8.5 Hz, 2H, H-3′ and
H-5′), 7.857 (d, J = 8.5 Hz, 2H, H-2′ and H-6′), 8.110 (s,
1H, H-9), 11.970 (s, 1H, NH); 13C-NMR (DMSO-d6, 150
MHz, ppm) δ = 64.35 (C-2), 116.23 (C-8), 122.29 (C-4a),
122.50 (C-6), 128.50 (C-5), 129.30 (C-2′ and C-6′), 129.50
(C-3), 129.89 (C-4), 130.10 (C-3′ and C-5′), 131.31 (C-7),
132.23 (C-1′),137.47 (C-4′), 147.70 (C-9), 154.63 (C-8a),
163.26 (C-10). HRESIMS m/z: found 313.07384 [M +
H]+:(calcd.: 313.073832 [M + H]+).
Yellow crystals, yield 75%, 0.426 g; m.p. 233–234 °C;
FTIR (ATR) cm−1 3290, 3029, 2932, 1650, 1630, 1604,
1590; 1H NMR (DMSO-d6, 600 MHz, ppm) 1:0.96 mixture
of conformers; signals for major E-imine isomer syn-amide
rotamer δ = 5.041 (s, 2H, H-2), 6.831 (d, J = 8.3 Hz, 1H,
H-8), 6.926 (dt, J = 1.1, 7.5 Hz, 1H, H-6), 6.945 (s, 1H, H-
4), 7.17–7.20 (m, 3H, H-7 and H-5 and H-4′), 7.843 (s, 2H,
H-9 and H-5′), 7.825 (d, J = 5.0 Hz, 1H, H-3′), 11.963 (s,
1H, NH); resolved signals for minor E-imine isomer anti-
amide bond rotamer: δ = 5.148 (s, 2H, H-2), 7.906 (d, J =
4.6 Hz, 1H, H-5′), 7.980 (d, J = 2.6 Hz, 1H, H-3′), 8.098 (s,
1H, H-9), 11.737 (s, 1H, NH); 13C-NMR (DMSO-d6, 150
MHz, ppm) signals for major synperiplanar conformer
around the amide bond δ = 64.33 (C-2), 116.20 (C-8),
122.31 (C-4a), 122.44 (C-6), 128.46 (C-7), 129.22 (C-3),
129.84 (C-4), 131.24 (C-5), 135.79 (C-3′), 135.65 (C-5′),
N′-[(E)-2H-Chromen-3-ylmethylidene]furan-2-
carbohydrazide (8b)
Yellow crystals, yield 72%, 0.386 g; m.p. 204–205 °C;
FTIR (ATR) cm−1 3246, 3030, 2850, 1652, 1632, 1602,