ChemicalBook CAS DataBase List Oroxylin A

Oroxylin A synthesis

12synthesis methods

Product Name:Oroxylin A
CAS Number:480-11-5
Molecular formula:C16H12O5
Molecular Weight:284.26

973-67-1

480-11-5

The general procedure for the synthesis of 5,7-dihydroxy-6-methoxy-2-phenyl-4H-benzopyran-4-one from 5,6,7-trimethoxy-2-phenyl-4H-benzopyran-4-one was as follows: 5,6,7-trimethoxy-2-phenyl-4H-benzopyran-4-one (0.20 g, 0.64 mmol) was dissolved in a mixture of 47% hydrobromic acid (5 mL) and glacial acetic acid (10 mL) in a mixed solution and the reaction was refluxed for 2 hours. Upon completion of the reaction, the reaction solution was quenched by carefully pouring it into crushed ice (200 g). The resulting yellow precipitate was collected by filtration and recrystallized from ethanol to afford 5,7-dihydroxy-6-methoxy-2-phenyl-4H-benzopyran-4-one (160 mg, 88% yield) with a melting point of 203-204 °C. The product structure was determined by 1H-NMR. The structure of the product was confirmed by 1H-NMR (DMSO-d6), IR, UV and MS analysis: 1H-NMR (DMSO-d6) δ: 3.91 (3H, s), 6.94 (1H, s), 6.98 (1H, s), 7.59 (3H, m), 8.10 (2H, d, J = 6.3 Hz), 8.77 (1H, s), 12.49 (1H, s); IR (KBr) cm-1: 3435, 1667; UV λmax (EtOH) nm (log ε): 322 (4.12), 278 (4.35), 216 (4.42); MS m/z: 285 (MH+).

973-67-1
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$57.00/5mg

480-11-5
194 suppliers
$50.00/10 mg

Yield:480-11-5 88%

Reaction Conditions:

with hydrogen bromide in acetic acid for 2 h;Heating / reflux;

Steps:

3 Example 3; Oroxylin A
A solution of flavone 2 (0.20 g, 0.64 mmol) in 47% HBr (5 ml) and glacial acetic acid (10 ml) was refluxed for 2 h, and then carefully poured onto crushed ice (200 g). The resulting yellow precipitate was filtered and collected. Recrystallization from ethanol afforded 160 mg (88%) of oroxylin A: mp 203-204 C. 1H-NMR (DMSO-d6) ?: 3.91 (3 H, s), 6.94 (1 H, s), 6.98 (1 H, s), 7.59 (3 H, m), 8.10 (2 H, d, J=6.3 Hz), 8.77 (1 H, s), 12.49 (1 H, s). IR (KBr) cm-1: 3435, 1667. UV ?max (EtOH) nm (log ?): 322 (4.12), 278 (4.35), 216 (4.42). MS m/z: 285 (MH+).

References:

Unitech Pharmaceuticals, Inc. US2004/242907, 2004, A1 Location in patent:Page 3

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82475-02-3 Synthesis