* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With malic acid In neat (no solvent) at 140℃; for 0.166667 h; Green chemistry
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.
91%
With ammonium acetate In neat (no solvent) at 114℃; for 0.0833333 h; Microwave irradiation
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.
91%
at 180℃;
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.
88%
With zinc(II) oxide In neat (no solvent) at 100℃; for 0.25 h; Microwave irradiation; Green chemistry
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.
78%
at 100℃; for 1 h;
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.
Reference：
[1] Heterocycles, 1986, vol. 24, # 9, p. 2511 - 2517
[2] Letters in Organic Chemistry, 2014, vol. 11, # 8, p. 601 - 605
[3] Journal of Chemical Research, 2005, # 9, p. 556 - 557
[4] Letters in Organic Chemistry, 2015, vol. 12, # 8, p. 574 - 583
[5] Letters in Organic Chemistry, 2016, vol. 13, # 10, p. 734 - 741
[6] Asian Journal of Chemistry, 2019, vol. 31, # 5, p. 1133 - 1136
[7] Molecules, 2018, vol. 23, # 9,
[8] Journal of Chemical Research - Part S, 1998, # 6, p. 348 - 349
[9] Journal of the Chinese Chemical Society, 2004, vol. 51, # 6, p. 1389 - 1394
[10] Journal of the Chemical Society, 1950, p. 1252,1257
[11] Journal of Organic Chemistry, 1991, vol. 56, # 26, p. 7292 - 7297
[12] Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2012, vol. 51, # 5, p. 770 - 773
[13] Synthetic Communications, 2013, vol. 43, # 11, p. 1549 - 1556
2
[ 104213-88-9 ]
[ 26964-24-9 ]
Yield
Reaction Conditions
Operation in experiment
92%
With dmap In N,N-dimethyl-formamide at 0 - 30℃; for 4 h; Inert atmosphere
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 NaHCO3, brine, dried over MgSO4, and filtered. The filtrate was concentrated in vacuo, and then the resulting residue was purified by column chromatography on silica gel to afford flavone 1 or 7. Spectral data of flavones 1a-1n and 7a-7c have been reported previously10.
Reference：
[1] Tetrahedron, 2011, vol. 67, # 51, p. 9993 - 9997
[2] Organic Letters, 2011, vol. 13, # 17, p. 4526 - 4529
[3] Advanced Synthesis and Catalysis, 2018, vol. 360, # 1, p. 153 - 160
3
[ 87428-52-2 ]
[ 100-52-7 ]
[ 26964-24-9 ]
Yield
Reaction Conditions
Operation in experiment
89%
at 70℃; for 6 h;
In 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]2[MoO4] (structural formula refer to embodiment 1), and 0.8170g (8mmol) tetrahydrofururyl alcohol solvent, stirring after mixing, heating to reaction temperature 70 °C, in 0.4 MPa stir to react under oxygen atmosphere 6h, cooled to the room temperature after the reaction, the solvent is removed by reduced pressure distillation after of tetrahydrofurfuryl alcohol, adding ethyl acetate and water extraction, the split-phase, passes through the column again chromatography and recrystallization of relative separation to obtain the target product 6-methoxy-flavone, the yield is 89percent, by nuclear magnetic resonance hydrogen spectrum, carbon spectrum and high-resolution mass spectrometry to determine its structural formula is:
Reference：
[1] Patent: CN105294627, 2016, A, . Location in patent: Paragraph 0097; 0098; 0099
4
[ 150-76-5 ]
[ 637-44-5 ]
[ 40547-03-3 ]
[ 26964-24-9 ]
Yield
Reaction Conditions
Operation in experiment
48%
With trifluoroacetic acid In chlorobenzene at 100℃; Inert atmosphere
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 H2O, neutralized with NaHCO3 solution and extracted CH2Cl2. The organic layer was washed with 2M NaOH, dried over anhydrous MgSO4. The solvent was removed in vaccum, and the products were purified by silica gel columnchromatography (EtOAc-Hex) to give the desired product 3.
48%
With trifluorormethanesulfonic acid In chlorobenzene at 100℃; for 3 h;
The 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 hours
With potassium hydroxide In water; acetone at 40℃; for 24 h;
6-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.
Reference：
[1] Organic Preparations and Procedures International, 2000, vol. 32, # 3, p. 280 - 283
17
[ 705-15-7 ]
[ 26964-24-9 ]
Reference：
[1] Journal of the Chinese Chemical Society, 2004, vol. 51, # 6, p. 1389 - 1394
[2] Journal of Organic Chemistry, 1991, vol. 56, # 26, p. 7292 - 7297
[3] Advanced Synthesis and Catalysis, 2018, vol. 360, # 6, p. 1218 - 1231
[4] Molecules, 2018, vol. 23, # 9,
18
[ 127745-66-8 ]
[ 26964-24-9 ]
Reference：
[1] Journal of the Chinese Chemical Society, 2004, vol. 51, # 6, p. 1389 - 1394
[2] Journal of Organic Chemistry, 1991, vol. 56, # 26, p. 7292 - 7297
[3] Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2012, vol. 51, # 5, p. 770 - 773
[4] Molecules, 2018, vol. 23, # 9,
19
[ 672-13-9 ]
[ 26964-24-9 ]
Reference：
[1] Journal of Pharmaceutical Sciences, 1992, vol. 81, # 8, p. 812 - 814
[2] Organic Letters, 2011, vol. 13, # 17, p. 4526 - 4529
[3] Tetrahedron, 2011, vol. 67, # 51, p. 9993 - 9997
20
[ 104213-88-9 ]
[ 26964-24-9 ]
[ 38216-58-9 ]
Reference：
[1] Journal of Organic Chemistry, 1986, vol. 51, # 23, p. 4432 - 4436
[2] Journal of Organic Chemistry, 1986, vol. 51, # 23, p. 4432 - 4436
[3] Journal of Pharmaceutical Sciences, 1992, vol. 81, # 8, p. 812 - 814
With tert.-butylhydroperoxide; tetra-(n-butyl)ammonium iodide; In decane; water; at 80℃;Green chemistry;
General procedure: An oven-dried 50 cm3 round bottom flask equipped witha magnetic stir bar was charged with chromanone 1a(0.7 mmol), n-Bu4NI [33, 34] (30 mol %), and aqueous solutionof TBHP (5-6 M in decane, 4 equiv.) at room temperature.The reaction mixture was then refluxed at 80 C for 5 h.The progress of the reaction was monitored by TLC. Afterthe completion of the reaction, the reaction mixture wasadmixed with ethyl acetate and transferred into a separating funnel. The ethyl acetate layer was sequentially washed with5% solution of sodium bicarbonate and brine solution. Thecombined organic layer was dried over anhydrous Na2SO4,filtered and concentrated in vacuum. The resulting residuewas purified over a column of silica gel (100-200 mesh) togive 2a-2s with petroleum ether/ethyl acetate as the eluent.
With malic acid; In neat (no solvent); at 140℃; for 0.166667h;Green chemistry;
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.
91%
With ammonium acetate; In neat (no solvent); at 114℃; for 0.0833333h;Microwave irradiation;
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 114C 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.
91%
With ascorbic acid; at 180℃;
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.
88%
With zinc(II) oxide; In neat (no solvent); at 100℃; for 0.25h;Microwave irradiation; Green chemistry;
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.
78%
With sulfuric acid; at 100℃; for 1h;
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: 78%; white solid, mp.: 163-165 C; 1H-NMR (CDCl3) delta 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) delta 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.
With dipotassium peroxodisulfate; silver nitrate; In water; acetonitrile; at 80℃; for 3h;
General procedure: O-hydroxyarylformic acid (1.0 mmol, R1=H),Aryl acetyl acid (1.1 mmol, R2 = H),Silver catalyst (5 mol%) and oxidant (2 mmol) were dispersed in a solvent (2 mL).Then in an air atmosphere,Stir at 80 C for 3 hours.After the reaction is over,Extract three times with Et2O (5 mL).Combine the organic phase,Concentrate under reduced pressure.The obtained crude product was subjected to column chromatography (300-400 mesh silica gel, petroleum ether and ethyl acetate as eluents).The target product was obtained.
77%
With [ruthenium(II)(eta6-1-methyl-4-isopropyl-benzene)(chloride)(mu-chloride)]2; cesium acetate; at 100℃; for 12h;
General procedure: Based on the results of Experimental Example 1, a flavone derivative (4) was synthesized from various substituted salicyaldehyde derivatives (1) and aryl alkynoic acid (2) using t-AmOH as a solvent. Salicylaldehyde (1.0 mmol), aryl alkynoic acid (1.0 mmol), dichloro (para-cymene) ruthenium (II) dimer ([Ru (p-cymene) Cl2) in a round bottom flask ] 2) (15 mg, 0.025 mmol, 2.5 mol%), cesium acetate (CsOAc) (384 mg, 2.0 mmol) and tert-BuOH solvent (5 mL) were added thereto, and the mixture was stirred at 100 C for 12 hours. The reaction solvent was cooled to room temperature, and then diluted with water. An aqueous hydrochloric acid solution was added to the diluted solution to adjust the acidity to 1 and extracted with ethyl acetate (EtOAc) solvent (25 ml, 2 times). The extracted organic solvent was washed with water (25 ml, twice) and then again with brine solution. Thereafter, the remaining water was removed using sodium sulfate and concentrated using a decompression device. The concentrated mixture was separated into pure compound using column chromatography filled with silica gel (developing solvent: 10% ethyl acetate / hexanes).As a result, as shown in FIG. 3, 2-phenyl-4H-chromen-4-one (4aa) was obtained in 60% yield, and the flavone derivative (4ba) was obtained. , 4da, 4ea and 4ha) were obtained in good yield. When salicylicaldehyde was reacted with p-tolylpropiolic acid and octynic acid, flavone derivatives (4ad and 4am) were obtained in 72% and 55% yield, respectively.
PREPARATION 17 6-Methoxy-2-phenyl-4H-4-chromenone The title product is obtained by condensation in sodium hydride of acetophenone with ethyl 5-methoxy-2-(methoxymethoxy)benzoate, and then the action of HCl in ethanol.
With dmap; In N,N-dimethyl-formamide; at 0 - 30℃; for 4h;Inert atmosphere;
General procedure: To a solution of o-alkynoylphenol 3 or 6 in DMF (4 mL/mmol) was added DMAP (10 mol %) 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 NaHCO3, brine, dried over MgSO4, and filtered. The filtrate was concentrated in vacuo, and then the resulting residue was purified by column chromatography on silica gel to afford flavone 1 or 7. Spectral data of flavones 1a-1n and 7a-7c have been reported previously10.
With iodine; In dimethyl sulfoxide;Inert atmosphere;
General procedure: Organic flavones 4a-j were synthesized by treating chalcones with I2 in DMSO according to a literature procedure [29]. The 1H NMR spectra of 4-c [30], 4e [31], 4f [32], 4g, 4h [33], 4i [34]and 4j [35] were consistent with those found in the literature. Compound 4d was not found in the literature, and its structure was deduced from its 1H NMR spectrum: deltaH (300 MHz; CDCl3) 6.84 (s, 1H, vinyl), 7.23-7.30 (m, 2H, C6H5), 7.54-7.56 (m, 1H, C6H5), 7.65-7.69 (m, 1H, C6H2), 7.93-7.96 (m, 2H, C6H5/C6H2).
With trifluoroacetic acid; In chlorobenzene; at 100℃;Inert atmosphere;
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 H2O, neutralized with NaHCO3 solution and extracted CH2Cl2. The organic layer was washed with 2M NaOH, dried over anhydrous MgSO4. The solvent was removed in vaccum, and the products were purified by silica gel columnchromatography (EtOAc-Hex) to give the desired product 3.
48%; 33%
With trifluorormethanesulfonic acid; In chlorobenzene; at 100℃; for 3h;
The 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 hours
With 1-butyl-3-methylimidazolium molybdate; oxygen; at 70℃; under 3000.3 Torr; for 6h;
In 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]2[MoO4] (structural formula refer to embodiment 1), and 0.8170g (8mmol) tetrahydrofururyl alcohol solvent, stirring after mixing, heating to reaction temperature 70 C, in 0.4 MPa stir to react under oxygen atmosphere 6h, cooled to the room temperature after the reaction, the solvent is removed by reduced pressure distillation after of tetrahydrofurfuryl alcohol, adding ethyl acetate and water extraction, the split-phase, passes through the column again chromatography and recrystallization of relative separation to obtain the target product 6-methoxy-flavone, the yield is 89%, by nuclear magnetic resonance hydrogen spectrum, carbon spectrum and high-resolution mass spectrometry to determine its structural formula is:
1-(2-acetoxy-5-methoxyphenyl)-3-phenyl-2-propyn-1-one[ No CAS ]
[ 26964-24-9 ]
Yield
Reaction Conditions
Operation in experiment
98%
With piperazine; In acetonitrile; at 25℃; for 3h;Schlenk technique;
General procedure: Under atmospheric conditions, 3 mL CH3CN without water was transferred into Schlenk tubes containing 1,3-yones 3aa-3eg(0.5 mmol), then piperazine (0.25 mmol) was added. The reaction mixture was stirred at 25C for 1.5 h-3 h. After the reaction proceed completely,and the organic layer was purified by column chromatography on silica gel using dichloromethane or ethylacetate/petroleum ether as eluent. All products 4aa-4eg were identified by comparing their spectral data with those of authentic samples.
97%
With piperazine; In acetonitrile; at 20℃; for 3h;Schlenk technique;
A 0. 147g (0. 5mmol) l- (2- acetoxy-5-methoxyphenyl) -3-phenyl-2-ethynyl-1-one and 0. 0252g (0. 3mmol) piperazine, 4mL of anhydrous acetonitrile to added schlenk tube, the reaction mixture was stirred at room temperature for 3 hours, the reaction was stopped by column chromatography to give a yellow solid of 6-methoxy-2-phenyl -4H- benzopyran - 4-one, and its yield was 97%.
With hydroxylamine hydrochloride; beta?cyclodextrin; In ethanol; water; at 80℃; for 0.5h;Sonication; Green chemistry;
General procedure: beta-cyclodextrin (10 mol%) was dissolved in water-ethanol (9:1) (20 mL), and to this clear solution 2-phenyl chromone (0.50 g, 1 mmol), and hydroxyl amine hydrochloride (0.28 g, 3 mmol), The reaction mixture was irradiated under ultrasonicationat 80C ultil the completion of reaction indicated by TLC. The reaction mixture was cooled to 5C and beta-CD was filtered and filtered reaction mixture was poured into ice cold water, the solid obtained was filtered and dried on vacuum pressure and crystallized from alcohol. The product was confirmedby 1H & 13C NMR and elemental analysis (Table 5).
With potassium hydroxide; In water; acetone; at 40℃; for 24h;
6-Hydroxyflavone (8.39 mmol) was dissolved in acetone (2mL), potassium hydroxide (20.89 mmol), as base and water(117 muL) were added to reaction mixture, which turned intoa yellow solid; then, drop-wise dimethylsulfate (159 muL)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 (5%), andthe mixture was shaken vigorously and filtered in vacuo toobtain 146.1 mg (yield of 63.8%). Compound was recrystallizedfrom ethanol, with a melting point of 162-163 C.
6-methoxyflavone 3'-O-β-D-(4”-O-methyl)-glucopyranoside[ No CAS ]
6-methoxyflavone 4'-O-β-D-(4”-O-methyl)-glucopyranoside[ No CAS ]
3'-hydroxy-6-methoxyflavone 4'-O-β-D-(4”-O-methyl)-glucopyranoside[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
7.8%; 7.9%
With Isaria fumosorosea KCH J2; In tetrahydrofuran; at 25℃;
Scale-up biotransformations were conducted in 2 L flasks containing 500 mL of the Sabouraudmedium. A duration of 72 h of incubation followed the inoculation after which 50 mg of the substratedissolved in 1 mL of tetrahydrofuran was added. The scale-up biotransformation was conductedunder analogous conditions to the screening (140 rpm, 25C). After the time was determined on the base of the screening experiments (different for each substrate used), the metabolites were extractedusing 200 mL of ethyl acetate (repeated three times, the procedure was as in the case of screening).The extracts were dried over MgSO4 and concentrated in vacuo. Product separation was carried out using preparative TLC plates or flash chromatography (in the case of 2'-methoxyflavanone (1)).The products structures were confirmed by means of spectroscopic methods (1H-NMR, 13C-NMR,COSY, HMBC, HSQC).The physical and spectral data of the products obtained are presented below (Tables 1-6)(Supplementary Materials).
General procedure: A sealed tube was charged with 1a (0.2 mmol, 1.0 equiv.), 2a (0.3 mmol, 1.5 equiv.), [Cp*RhCl2]2 (0.005 mmol, 2.5 mol%), and CsOAc (0.1 mmol, 0.5 equiv.) in DCE (2 mL). After the reaction mixture had been stirred at 100 C under Ar for 6 h, 1 mL of H2SO4/HOAc (10 muL of H2SO4 dissolved in 0.99 mL of HOAc) was added at room temperature. After completion of the addition, the reaction mixture was then stirred at 100 C for 3 h before being cooled to room temperature. The mixture was diluted with EtOAc (20 mL), washed with brine, and dried over anhydrous Na2SO4. After removal of the EtOAc, the residue was purified by chromatography on basic silica gel (PE/EtOAc = 8/1) to afford 3aa (40 mg, 89%) as a white solid.
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