ChemicalBook CAS DataBase List 7-(benzyloxy)-5-hydroxy-2-phenyl-4H-chromen-4-one

7-(benzyloxy)-5-hydroxy-2-phenyl-4H-chromen-4-one synthesis

6synthesis methods

Product Name:7-(benzyloxy)-5-hydroxy-2-phenyl-4H-chromen-4-one
CAS Number:110506-85-9
Molecular formula:C22H16O4
Molecular Weight:344.36

2-phenyl-5,7-bis(phenylmethoxy)chromen-4-one

137790-18-2
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7-(benzyloxy)-5-hydroxy-2-phenyl-4H-chromen-4-one

110506-85-9
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Yield:110506-85-9 98%

Reaction Conditions:

with titanium tetrachloride in dichloromethane at 0 - 20; for 2 h;

Steps:

4.3.3. 5-Benzoyloxy-7-benzyloxyflavone (1j)

A solution of TiCl₄ (1 M in CH₂Cl₂, 0.31 mL, 0.31 mmol) was added dropwise to a solution of 5,7-dibenzyloxyflavone (1k)⁵ (0.220 g, 0.476 mmol) in anhydrous CH₂Cl₂ (5 mL) at 0 °C and the reaction mixture was allowed to warm to room temperature over 2 h. The reaction mixture was carefully added to a stirred solution of saturated aqueous NaHCO₃ (30 mL) and extracted with CH₂Cl₂ (3×50 mL). The combined organic layers were dried (Na₂SO₄), filtered and the volatiles were removed in vacuo to afford crude 7-benzyloxy-5-hydroxyflavone (0.170 g, 98%) as an orange solid, which was used without further purification. Benzoyl chloride (0.5 mL) was then added to a solution of this flavone (0.17 g, 0.51 mmol) in anhydrous pyridine (3 mL) at 0 °C and the reaction mixture was stirred at 60 °C for 5 h then at room temperature for 48 h. The reaction mixture was quenched with methanol and the volatiles were removed in vacuo. The residue was diluted with CH₂Cl₂ (20 mL) and the organic phase was washed with dil HCl (1 M, 20 mL), brine (20 mL), dried (MgSO₄), filtered and volatiles were removed in vacuo. The crude product was purified by column chromatography on silica gel (20 g, CH₂Cl₂ elution) to afford 1j (0.180 g, 79%) as a white solid; mp 137-138 °C; ¹H NMR (500 MHz, CDCl₃) δ_H 5.20 (s, 2H, PhCH₂O), 6.60 (s, 1H, H-3), 6.85 (d, J=2.5 Hz, 1H, H-6), 7.02 (d, J=2.5 Hz, 1H, H-8), 7.43 (m, 5H, H-2, 6), 7.52 (m, 3H, H-3', 4', 5'), 7.52 (dd, J=8.5, 8.5 Hz, 2H, H-3, 5), 7.64 (dd, J=8.5, 8.5 Hz, 1H, H-4), 7.85 (dd, J=1.0, 7.5 Hz, 2H, H-2', 6'), 8.26 (dd, J=1.5, 8.5 Hz, 2H, H-2, 6); ¹³C NMR (125 MHz, CDCl₃) δ_C 70.9 (t, PhCH₂O), 100.2 (d, C-8), 108.6 (d, C-3), 109.2 (d, C-6), 111.7 (s, C-4a), 126.2 (2×d, C-2', 6'), 127.7 (2×d, C-2, 6), 128.6 (2×d, C-3, 5), 128.6 (d, C-4), 128.9 (2×d, C-3, 5), 129.1 (3×d, C-3', 4', 5'), 129.9 (s, C-1), 130.5 (2×d, C-2, 6), 131.5 (s, C-1'), 133.4 (d, C-4), 135.5 (s, C-1), 150.9 (s, C-5), 158.9 (s, C-8a), 162.1 (s, C-2), 162.7 (s, C-7), 165.4 (s, PhCOO), 176.5 (s, C-4); IR (thin film) ν_max 3062, 1740, 1645, 1493, 1450, 1375, 1351, 1262, 1159, 1093, 1058, 1028, 696 cm^-1; HRMS (+ve ESI) m/z 449.1365 [M+H]⁺ (calcd for C₂₉H₂₁O₅ [M+H]⁺ 449.1384).