J IRAN CHEM SOC
General procedure for the synthesis of 9‑ben‑
zoyl‑2‑phenylpyrano[2,3‑f]chromene‑4,8‑diones 5a–i
9‑(4‑Chlorobenzoyl)‑2‑phenylpyrano[2, 3‑f]
chromene‑4,8‑dione (5d): Off white solid: mp 244–
246 °C. FTIR (KBr, cm−1): 1628 (C=O), 1678 (C=O),
1736 (C=O). 1H NMR (400 MHz, CDCl3): δ 8.62 (s, 1H),
8.29 (d, 1H, J = 9.0 Hz), 8.11 (d, 2H, J = 8.4 Hz), 8.03 (d,
2H, J = 8.6 Hz), 7.94 (d, 2H, J = 8.4 Hz), 7.86 (m, 1H),
7.50–7.61 (m, 3H), 6.90 (s, 1H). 13C NMR (100 MHZ,
CDCl3): δ 190.1, 178.1, 161.6, 157.9, 155.4, 154.3, 138.8,
135.6, 133.9, 133.9, 130.1, 129.8, 129.2, 128.9, 128.6,
128.0, 127.1, 126.9, 125.2, 121.4, 118.9, 116.2, 112.1,
106.4. ESI-MS: m/z 429 [M+H].
To the solution of 7-hydroxy-8-formylflavones 2a–c
(1 mmol) in ethanol were added benzoyl acetonitrile 3a–c
(1 mmol) and l-proline (30 mol %) at rt. The reaction mix-
ture was stirred for 20 min at 60 °C, and 3 mL of conc.
HCl was added. Then, the resulting solution was refluxed
for 1 h. After completion of the reaction, the mixture was
diluted with ice-cold water and extracted with EtOAc.
Then, the solvent layer was dried over Na2SO4, filtered
and distilled under vacuum. The obtained residue was
purified by column chromatography to gave 9-benzoyl-
2-phenylpyrano[2,3-f]chromene-4,8-diones 5a–i as off
white solid with 78–84% of yield.
9‑(4‑Chlorobenzoyl)‑3‑methyl‑2‑phenylpyrano[2,3‑f]
chromene‑4,8‑dione (5e):
9‑Benzoyl‑2‑phenylpyrano[2,3‑f]chromene‑4,8‑dione
(5a): Off white solid: mp 233–235 °C. FTIR (KBr,
Off white solid: mp 238–240 °C. FTIR (KBr, cm−1):
1629 (C=O), 1682 (C=O), 1740 (C=O). 1H NMR
(400 MHz, CDCl3): δ 8.52 (s, 1H), 8.32 (d, 1H, J = 9.0 Hz),
8.11 (d, 2H, J = 8.4 Hz), 8.01 (d, 2H, J = 8.6 Hz), 7.92 (d,
2H, J = 8.4 Hz), 7.80–7.91 (m, 1H), 7.48–7.56 (m, 3H),
2.16 (s, 3H). 13C NMR (100 MHZ, CDCl3): δ 190.5, 178.1,
163.6, 158.9, 156.3, 154.1, 136.5, 134.2, 133.6, 133.1,
130.5, 129.8, 129.2, 128.9, 128.7, 128.0, 127.8, 127.1,
127.0, 126.9, 125.1, 121.2, 118.9, 113.3, 106.4, 11.0. ESI-
MS: m/z 433 [M+H].
1
cm−1): 1620 (C=O), 1688 (C=O), 1734 (C=O). H NMR
(400 MHz, CDCl3): δ 8.58 (s, 1H), 8.35 (d, 1H, J = 9.0 Hz),
8.0 (d, 2H, J = 8.6 Hz), 7.81–7.89 (m, 2H), 7.69–7.74 (m,
1H), 7.51–7.61 (m, 7H). 13C NMR (100 MHz, CDCl3): δ
191.1, 178.1, 163.6, 158.9, 156.3, 154.2, 136.6, 134.3,
133.7, 133.1, 130.5, 129.8, 129.2, 128.9, 128.0, 127.8,
127.2, 125.5, 121.0, 118.9, 113.4, 107.5. ESI-MS: m/z 395
[M+H].
9‑(4‑Chlorobenzoyl)‑3‑ethyl‑2‑phenylpyrano[2,3‑f]
9‑Benzoyl‑3‑methyl‑2‑phenylpyrano[2, 3‑f]
chromene‑4,8‑dione (5b): Off white solid: mp 220–
222 °C. FTIR (KBr, cm−1): 1620 (C=O), 1658 (C=O),
1722 (C=O). 1H NMR (400 MHz, CDCl3): δ 8.49 (s, 1H),
8.26 (d, 1H, J = 9.0 Hz), 8.02 (d, 2H, J = 8.6 Hz), 7.81–
7.89 (m, 2H, Ar–H), 7.51–7.69 (m, 7H, Ar–H), 2.12 (s,
3H). 13C NMR (100 MHz, CDCl3): δ 190.8, 178.1, 162.4,
157.6, 156.1, 154.0, 135.8, 133.9, 133.2, 133.1, 130.2,
129.8, 129.1, 128.9, 128.1, 127.8, 126.9, 125.0, 121.1,
118.4, 114.2, 105.6, 11.8. ESI-MS: m/z 407 [M-H].
chromene‑4,8‑dione (5f):
Off white solid: mp 218–220 °C. FTIR (KBr, cm−1):
1622 (C=O), 1656 (C=O), 1738 (C=O). 1H NMR
(400 MHz, CDCl3): δ 8.52 (s, 1H), 8.28 (d, 1H, J = 9.0 Hz),
8.10 (d, 2H, J = 8.4 Hz), 7.98 (d, 2H, J = 8.6 Hz), 7.91 (d,
2H, J = 8.6 Hz), 7.78–7.89 (m, 1H), 7.50–7.59 (m, 3H),
2.28 (q, 2H, J = 7.5 Hz), 1.14 (t, 3H, J = 7.5 Hz). 13C
NMR (100 MHz, CDCl3): δ 191.0, 180.0, 163.1, 158.2,
156.3, 154.4, 136.6, 134.0, 133.2, 133.4, 130.1, 129.9,
129.3, 128.6, 128.1, 127.8, 126.8, 125.1, 121.2, 118.8,
112.3, 106.8, 29.1, 14.5. ESI-MS: m/z 457 [M+H].
9 ‑ B e n z o y l ‑ 3 ‑ e t h y l ‑ 2 ‑ p h e n y l p y r a n o [ 2 , 3 ‑ f ]
chromene‑4,8‑dione (5c):
9‑(4‑Methylbenzoyl)‑2‑phenylpyrano[2,3‑f]
chromene‑4,8‑dione (5 g): Off white solid: mp 233–
235 °C. FTIR (KBr, cm−1): 1618 (C=O), 1652 (C=O),
1731 (C=O). 1H NMR (400 MHz, CDCl3): δ 8.46 (s, 1H),
8.22 (d, 1H, J = 9.0 Hz), 8.02 (d, 2H, J = 8.6 Hz), 7.91 (d,
2H, J = 8.4 Hz), 7.80–7.86 (m, 1H), 7.51–7.61 (m, 5H),
6.88 (s, 1H), 2.38 (s, 3H). 13C NMR (100 MHZ, CDCl3):
δ 190.9, 177.3, 163.5, 158.4, 157.2, 153.1, 144.8, 138.3,
133.4, 132.3, 130.7, 130.4, 129.8, 129.4, 129.4, 127.7,
125.9, 120.6, 114.5, 108.3, 108.4, 22.1. ESI-MS: m/z 409
[M+H].
Off white solid: mp 218–219 °C. FTIR (KBr, cm−1):
1622 (C=O), 1666 (C=O), 1732 (C=O). 1H NMR
(400 MHz, CDCl3): δ 8.46 (s, 1H), 8.29 (d, 1H, J = 9.0 Hz),
7.98 (d, 2H, J = 8.6 Hz), 7.81–7.89 (m, 2H), 7.51–7.61 (m,
7H), 2.11 (q, 2H, J = 7.5 Hz), 1.13 (t, 3H, J = 7.5 Hz). 13
C
NMR (100 MHz, CDCl3): δ 190.0, 178.1, 161.5, 158.6,
156.1, 153.9, 135.2, 134.0, 133.1, 133.0, 130.8, 129.9,
129.2, 128.7, 128.4, 127.9, 126.6, 125.1, 121.3, 118.3,
113.1, 104.9, 28.2, 13.3. ESI-MS: m/z 423 [M+H].
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