6-Methoxyflavone

General procedure: The mixture of 1-(2-hydroxyphenyl)-3-aryl-1, 3-propanedione 1a (0.5 g) and malic acid (1.0 eq.) was heatedeither in an oil bath, preheated at 140 °C for 10 min or in amicrowave reactor for 5 min. After the completion of reaction(TLC check), the reaction mixture was allowed to cool;at room temperature water (10 mL) and ethyl acetate (10mL) were added. Reaction mixture was neutralized by additionof solid NaHCO3. Organic layer was separated and theaqueous layer was extracted in ethyl acetate (2 10 mL).Combined organic extract was dried over anhydrous sodiumsulfate and concentrated in vacuo. The crude product waspurified by column chromatography on silica gel using hexane-ethylacetate solvent system to give the correspondingflavones in high yield.General procedure: The mixture of 1-(2-hydroxyphenyl)-3-aryl-1, 3-propanedione 1a (0.5 g, 2.08 mmol) and ammonium acetate (0.16 g, 2.08 mmol) was heated either in an oil bath, preheated at 114°C for 10 min or in a microwave reactor for 5min. After the pH of the reaction mixture was brought back to 7.0 by the careful addition of NaHCO3 solution. The aqueous layer was extracted with ethyl acetate, dried(Na2SO4), and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using hexane-ethyl acetate solvent system to give the corresponding flavones in high yield.General procedure: The mixture of 1-(2-hydroxyphenyl)-3-aryl-1, 3-propanedione 4a-q (0.5g, 2.08 mmol) and L-ascorbic acid(3.7g, 2.08 mmol) was heated on a preheated oil bath or undermicrowave irradiation at 180 °C for 2-3 min. After completionof reaction (TLC check), the reaction mixture wascooled to room temperature and the flask was sonicated byadding excess water. The crude product was filtered oversuction-pump and washed with excess of water to removeL-ascorbic acid. The solid obtained was dried and crystallizedby using ethanol to give the corresponding flavones inhigh yield. The purity of products was confirmed by satisfactoryspectroscopic data.General procedure: A mixture of substituted 1, 3-propanedione (0.5 g, 2.08 mmol, 1.0 eq.) and ZnO nanoparticles (1.0eq.) was heated in a microwave oven for 15 min. Same procedure used for purification of flavones as mentioned in the conventional heating method.General procedure: Compounds 4a–j (1.8 g) glycerol triacetate (10 mL) and concentrated sulfuric acid (0.4 mL) wereplaced in a round bottomed flask equipped with a reflux condenser, stirred about 1 h at 100 C andthen the mixture was poured into a beaker containing 50 g of crushed ice, where solids were formedafter stirring and then filtered from the solution, Next the solids were washed with water until the acidwas removed. Finally, the solids were purified and separated by column chromatography eluting witha mixed petroleum ether and ethyl acetate solvent until the final products 5a–j were obtained. 6-Methoxyflavone (5a). Yield: 78percent; white solid, mp.: 163–165 °C; 1H-NMR (CDCl3) δ 7.93–7.80 (m, 1H), 7.52 (t, J = 7.6 Hz, 2H), 7.51–7.39 (m, 1H), 7.24 (d, J = 3.1 Hz, 1H), 7.22 (d, J = 3.1 Hz, 2H), 7.19 (s, 1H), 6.79 (s, 1H), 3.85 (s, 3H); 13C-NMR (CDCl3) δ 177.27, 162.12, 155.98, 150.04, 130.83, 130.46, 127.99, 127.99, 125.20, 125.20, 123.52, 122.76, 118.48, 105.79, 103.81, 54.90. MS (ESI-MS) m/z calcd for C16H12O3[M + H]+: 253.26; found: 253.28.General procedure: To a solution of o-alkynoylphenol 3 or 6 in DMF (4 mL/mmol) was added DMAP (10 mol percent) at 0 °C under argon. After being stirred at 30 °C, the reaction mixture was diluted with water. The aqueous layer was extracted twice with ethyl acetate. The organic layer was washed with 1 M HCl, saturated aqueous NaHCOIn 10 ml in the reaction kettle, successively added 0.3183g (3mmol) benzaldehyde, 0.3323g (2mmol) 5-methoxy-2-hydroxy acetophenone and 0.2630g (0.6mmol) of the ionic liquid catalyst [Bmim]General procedure: A mixture of Phenol derivatives (1) (1.0 mmol), trifluoromethanesulfonic acid (1.0 mmol) and propiolic acid (2a) (0.5 mmol) in PhCl (3.0 mL) was stirred at 100 °C for 1 h. After completion of reaction as indicated by TLC, the reaction mixture was poured into HThe title compound was synthesized in the same manner as in Example 1, except that 4-methoxyphenol was used instead of phenol, 3-phenylpropiolic acid was used instead of propiolic acid, and the reaction time was 3 hours6-Hydroxyflavone (8.39 mmol) was dissolved in acetone (2mL), potassium hydroxide (20.89 mmol), as base and water(117 μL) were added to reaction mixture, which turned intoa yellow solid; then, drop-wise dimethylsulfate (159 μL)was added and the mixture was heated at 40 °C for 24 h(monitored by TLC). The reaction mixture was washed withice water (2 mL) and filtered under vacuum. Finally, thesolid product (146.1 mg) was washed with NaOH (5percent), andthe mixture was shaken vigorously and filtered in vacuo toobtain 146.1 mg (yield of 63.8percent). Compound was recrystallizedfrom ethanol, with a melting point of 162–163 °C.

Molecular Weight:252.26
XLogP3:3.9
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:2
Exact Mass:252.078644241
Monoisotopic Mass:252.078644241
Topological Polar Surface Area:35.5
Heavy Atom Count:19
Complexity:368
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes