Molecular Diversity
Major isomer: 181.8 (C-4), 163.6 (C-2), 154.95 (C-8a),
154.92 (C-9), 137.7 (C-1ʹ), 134.8 (C-7), 130.18 (C-3′/5′),
127.5 (C-4ʹ), 126.6 (C-5), 124.2 (C-6), 120.3 (C-4a), 118.45
(C-2′/6′), 117.43 (C-8), 98.7 (C-3). Minor isomer: 178.6
(C-4), 165.2 (C-2), 154.7 (C-8a), 153.4 (C-9), 137.7 (C-1ʹ),
134.7 (C-7), 130.16 (C-3′/5′), 127.4 (C-4ʹ), 125.8 (C-5),
124.4 (C-6), 120.6 (C-4a), 118.51 (C-2′/6′), 117.37 (C-8),
98.8 (C-3). IR νmax (cm−1) 3180, 1684, 1594, 1567, 755.
APCI-HRMS m/z calcd. for C16H12NO3, 266.0812, [M+H]+
found 266.0807. Purity (HPLC): 90%.
C-3′/5′)*, 126.6 (C-4′), 125.3 (C-5), 123.95 (C-6), 120.3
(C-4a), 116.9 (C-8), 95.6 (C-3), 51.6 (C-10), 35.8 (C-11).
Minor isomer: 177.0 (C-4), 163.2 (C-2), 160.6 (C-9), 154.1
(C-8a), 137.9 (C-1′), 134.4 (C-7), 128.9, 128.5 (C-2′/6′,
C-3′/5′)*, 126.6 (C-4′), 125.8 (C-5), 124.04 (C-6), 120.4
(C-4a), 117.0 (C-8), 95.3 (C-3), 51.7 (C-10), 35.9 (C-11). IR
νmax (cm−1) 3063, 1708, 1590, 1463, 741. APCI-HRMS m/z
calcd. for C18H16NO3, 294.1125, [M+H]+ found 294.1129.
Purity (HPLC): 100%. *In no particular order.
(3E/Z)‑3‑{[(3‑Phenylpropyl)amino]methylidene}‑3,4‑dihy-
dro‑2H‑1‑benzopyran‑2,4‑dione (14d) The title compound
was prepared from chromone-3-carboxylic acid and 3-phe-
nyl-1-propylamine in a yield of 58%: mp. 171.3–171.6 °C
(methanol), white crystals. Ratio of major isomer: minor
isomer 1:0.7. 1H NMR (600 MHz, DMSO-d6) δ Major iso-
mer: 11.76–11.57 (m, 1H, NH), 8.44 (d, J= 14.7 Hz, 1H,
H-9), 7.96–7.89 (m, 1H, H-5), 7.68–7.61 (m, 1H, H-7),
7.40–7.08 (m, 7H, H-6, H-8, H-2′–6′)*, 3.60 (q, J=6.8 Hz,
2H, H-10), 2.64–2.57 (m, 2H, H-12), 1.95 (p, J = 7.3 Hz,
2H, H-11). Minor isomer: 10.52–10.21 (m, 1H, NH), 8.55
(d, J=15.5 Hz, 1H, H-9), 7.96–7.89 (m, 1H, H-5), 7.68–7.61
(m, 1H, H-7), 7.40–7.08 (m, 7H, H-6, H-8, H-2′–6′), 3.60
(q, J=6.8 Hz, 2H, H-10), 2.64–2.57 (m, 2H, H-12), 1.95 (p,
J=7.3 Hz, 2H, H-11). 13C NMR (151 MHz, DMSO-d6) δ
Major isomer: 179.3 (C-4), 162.7 (C-2), 162.2 (C-9), 154.2
(C-8a), 140.9 (C-1′), 134.28 (C-7), 128.4, 128.3 (C-2′/6′,
C-3′/5′)*, 125.9 (C-4ʹ), 125.3 (C-5), 123.9 (C-6), 120.3
(C-4a), 116.9 (C-8), 95.7 (C-3), 50.0 (C-10), 31.9 (C-12),
31.15 (C-11). Minor isomer: 177.1 (C-4)**, 163.5 (C-2),
160.6 (C-9), 154.2 (C-8a), 140.9 (C-1′), 134.33 (C-7), 128.4,
128.3 (C-2′/6′, C-3′/5′)*, 125.7 (C-4′), 125.3 (C-5), 124.0
(C-6), 120.5 (C-4a), 117.0 (C-8), 95.7 (C-3), 50.2 (C-10),
31.9 (C-12), 31.2 (C-11). IR νmax (cm−1) 3023, 1711,
1603, 1462, 752. APCI-HRMS m/z calcd. for C19H18NO3,
308.1281, [M+H]+ found 308.1280. Purity (HPLC): 100%.*
In no particular order. **Shift based on HMBC correlation,
signal not visible on 13C NMR.
(3E/Z)‑3‑[(Benzylamino)methylidene]‑3,4‑dihydro‑2H‑1‑ben-
zopyran‑2,4‑dione (14b) The title compound was prepared
from chromone-3-carboxylic acid and benzylamine in a
167 °C, [41]), pink crystals. Ratio of major isomer: minor
mer: 11.96–11.88 (m, 1H, NH), 8.62 (d, J= 14.6 Hz, 1H,
H-9), 7.89 (dd, J = 7.8, 1.4 Hz, 1H, H-5), 7.67–7.58 (m,
1H, H-7), 7.44–7.23 (m, 7H, H-6, H-8, H-2′–6′)*, 4.82 (d,
J=6.2 Hz, 2H, H-10). Minor isomer: 10.71–10.65 (m, 1H,
NH), 8.72 (d, J=15.4 Hz, 1H, H-9), 7.93 (br d, J=7.7 Hz,
1H, H-5), 7.67–7.58 (m, 1H, H-7), 7.44–7.23 (m, 7H,
H-6, H-8, H-2′–6′)*, 4.82 (d, J = 6.2 Hz, 2H, H-10). 13C
NMR (151 MHz, DMSO-d6) δ Major isomer: 179.4 (C-4),
162.7 (C-2), 162.2 (C-9), 154.2 (C-8a), 136.7 (C-1′), 134.3
(C-7), 128.8 (C-2′/C-6′ or C-3′/C-5′), 128.0 (C-2′/C-6′ or
C-3′/C-5′), 127.98 (C-4′), 125.3 (C-5), 123.9 (C-6), 120.2
(C-4a), 116.9 (C-8), 96.0 (C-3), 53.2 (C-10). Minor isomer:
177.1 (C-4), 163.2 (C-2), 160.6 (C-9), 154.1 (C-8a), 137.0
(C-1′), 134.4 (C-7), 128.8 (C-2′/C-6′ or C-3′/C-5′), 128.0
(C-2′/C-6′ or C-3′/C-5′), 127.9 (C-4′), 125.8 (C-5), 124.0
(C-6), 120.4 (C-4a), 117.0 (C-8), 95.9 (C-3), 53.1 (C-10). IR
νmax (cm−1) 3033, 1708, 1592, 1463, 746. APCI-HRMS m/z
calcd. for C17H14NO3, 280.0968, [M+H]+ found 280.0972.
Purity (HPLC): 100%. *In no particular order.
(3E/Z)‑3‑{[(2‑Phenylethyl)amino]methylidene}‑3,4‑dihy-
dro‑2H‑1‑benzopyran‑2,4‑dione (14c) The title compound
was prepared from chromone-3-carboxylic acid and pheneth-
ylamine in a yield of 59%: mp. 178.2–178.7 °C (methanol),
white crystals. Ratio of major isomer: minor isomer 1:0.5.
1H NMR (600 MHz, DMSO-d6) δ Major isomer: 11.68–
11.62 (m, 1H, NH), 8.34 (d, J=14.3 Hz, 1H, H-9), 7.90 (dd,
J=7.7, 1.7 Hz, 1H, H-5), 7.66–7.59 (m, 1H, H-7), 7.33–7.17
(m, 7H, H-2ʹ–6ʹ, H-8, H-6)*, 3.83 (q, J=6.7 Hz, 2H, H-10),
2.96 (t, J = 7.2 Hz, 2H, H-11). Minor isomer: 10.40 (br s,
1H, NH), 8.45 (d, J=14.8 Hz, 1H, H-9), 7.90 (dd, J=7.7,
1.7 Hz, 1H, H-5), 7.66–7.59 (m, 1H, H-7), 7.33–7.17 (m,
7H, H-2ʹ–6ʹ, H-8, H-6)*, 3.83 (q, J=6.7 Hz, 2H, H-10), 2.96
(t, J=7.2 Hz, 2H, H-11). 13C NMR (151 MHz, DMSO-d6) δ
Major isomer: 179.3 (C-4), 162.7 (C-2), 162.2 (C-9), 154.2
(C-8a), 137.9 (C-1′), 134.3 (C-7), 128.9, 128.5 (C-2′/6′,
(3E/Z)‑3‑{[(4‑Phenylbutyl)amino]methylidene}‑3,4‑dihy-
dro‑2H‑1‑benzopyran‑2,4‑dione (14e) The title compound
was prepared from chromone-3-carboxylic acid and 4-phe-
nylbutylamine in a yield of 13%: mp. 142.4–143.3 °C (meth-
anol), white crystals. Ratio of major isomer: minor isomer
1:0.4. 1H NMR (600 MHz, CDCl3) δ Major isomer: 11.86
(br s, 1H, NH), 8.34 (d, J = 14.1 Hz, 1H, H-9), 7.99 (dd,
J = 7.8, 1.7 Hz, 1H, H-5), 7.54 (ddd, J = 8.4, 7.4, 1.7 Hz,
1H, H-7), 7.30–7.12 (m, 7H, H-6, H-8, H-2ʹ–H-6ʹ)*, 3.50
(q, J = 6.4 Hz, 2H, H-10), 2.65 (t, J = 6.8 Hz, 2H, H-13),
1.79–1.66 (m, 4H, H-11, H-12)*. Minor isomer: 10.21 (br
s, 1H, NH), 8.50 (d, J=14.9 Hz, 1H, H-9), 8.07 (dd, J=7.8,
1.6 Hz, 1H, H-5), 7.57–7.53 (m, 1H, H-7), 7.30–7.12 (m,
7H, H-6, H-8, H-2ʹ–H-6ʹ)*, 3.52 (q, J=6.4 Hz, 2H, H-10),
1 3