5-(benzyloxy)-2-(hydroxymethyl)-4H-pyran-4-one

Kojic acid (11) (14.20 g, 100 mmol) was dissolved in methanol (100 mL), and sodium hydroxide (4.40 g, 110 mmol) in water (10 mL) was added. The 10 mmol kojic acid is added to the 50 ml reaction in the bottle, by adding 20 ml of methanol, stirring and dissolving, adding 11 mmol potassium hydroxide, heating to reflux, dropping 11 mmol benzyl chloride, paused after backflow state thermal reaction. TLC tracking reaction, after the reaction, cooling to room temperature, pressure reducing evaporate the solvent, by adding 30 ml of dichloromethane, fully mixing, filtering, dichloromethane and washing the solid getting white solid. Methylene chloride fluid respectively through the 10percent sodium hydroxide solution, washed, dried with anhydrous sodium sulfate, concentrated under reduced pressure, the residue and the like to ethanol to recrystallize the product yield is 83.4percent.Add 10 mmol of kojic acid to a 50 ml reaction flask.Add 20 ml of methanol, stir to dissolve, add 11 mmol of potassium hydroxide, The temperature was raised to reflux, and 11 mmol of benzyl chloride was added dropwise, and after the completion of the dropwise addition, the reaction was kept under reflux. The reaction was followed by TLC. After the reaction was completed, it was cooled to room temperature.The solvent was evaporated under reduced pressure, and dichloromethane (30 ml) was added and stirred well.Filtration and washing of the methylene chloride afforded a white solid.The methylene chloride solution was washed with 10percent sodium hydroxide solution and water, respectively.Dry over anhydrous sodium sulfate and concentrate under reduced pressure.The yield of the product, which was recrystallized from ethanol, was 83.4percent.To a solution of compound 4-a (RStep 1-2 : 5-Benzyloxy-2-hydroxymethyl-pyran-4-one (4-b, R To a solution of kojic acid (7.3g, 50mmol) in MeOH was added 11M NaOH (5ml, 55mmol). The mixture was heated to reflux (80Further, as another method, it was possible following method. Kojic acid (20.0 g, 0.14 mol) in methanol (140 ml) of aqueous sodium hydroxide (14 ml, 6.2 g, 0.155 mo) was added, Heating under reflux, was added dropwise benzyl chloride (19.7 g, 0.155 mol), overnight, was continued to reflux. The reaction mixture was concentrated under reduced pressure, with the addition of water (200ml) to the residue was suction filtered solids. The crude crystals were recrystallized from methanol 2 (23.0g, 71percent) was obtained as colorless needle crystals.A. To a solution of kojic acid 5 (28.4 g, 0.2 mol) in methanol (200ml) was added sodium hydroxide (8.8 g, 0.2 mol) dissolved in water (20ml) and the mixture was heated to reflux. Benzyl chloride (28g, 0.2 mol) was added dropwise over 30 min, and the resulting mixture was refluxed overnight. After removal of solvent by rotary evaporation, the brown solid was washed with water (80ml) followed by methanol (40ml) then recrystallization from methanol gave the pure product (24.51g, 53.2percent). Step 1 : Preparation of C22. A suspension of C10 (48.92 g, 344.2 mmol) in methanol (313 mL) was treated with 1 M aqueous sodium hydroxide (32 mL, 379 mmol). To the mixture was added benzyl bromide (64.8 g, 379 mmol) dropwise over 10 minutes. The reaction mixture was refluxed overnight, then cooled to room temperature and treated with 1 N aqueous hydrochloric acid (600 mL) and stirred at room temperature for 20 minutes. The mixture was filtered and the solids washed with water (3 x 200 mL), then stirred in a mixture of heptanes (180 mL) and ethyl acetate (120 mL). The solid was collected by filtration to provide C22. Yield: 62.5 g, 269.0 mmol, 78percent. LCMS m/z 233.3 (M+1 ). Preparation of 5-benzyloxy-2-hydroxymethyl-pyran-4-one; A 10M NaOH solution (110 mL, 1.10 mol) was added to a suspension of kojic acid (142.1 g, 1.00 mol) in methanol (1 L) with mechanical stirring at room temperature. Benzyl bromide (137.0 mL, 1.15 mol) was added, and the resulting clear yellow solution was refluxed using a heating mantle for 3 h. The progress of the reaction was monitored by TLC using a mixture of CHThe compound kojic acid 1 (10 g, 0.07 µM) dissolved in 50 ml in methanol, adding NaOH (3 g, 0.077 µM), is heated to 75 - 80 °C after, to 0.5 - 2 ml/min [...] (12 g, 0.07 µM), after dropping, 75 - 80 °C overnight reflux reaction; after the reaction, pressure and concentration to obtain a residue, the residue is dissolved in 200 ml water, insoluble and filtering to obtain the filter cake, the filter cake drying of the crude product, the crude product is used for methanol/ethyl ether recrystallization, shall be brown solid compound 10 (12 g, 74.1percent).[0464] 5-(Benzyloxy)-2-(hydroxymethyl)-4H-pyran-4-one (77): Kojic acid (15g, 106 mmol) and potassium carbonate (32.1 g, 232 mmol) were dissolved in DMF (200 mL) and stirred. (0993) Benzyl bromide (15.07 mL, 127 mmol) was added and the mixture was heated to 80°C for 6-8 hours. Solvent was then evaporated under vacuum, and the residue was recrystallized in water to give compound 77 (24.7 g, 72percent) as white, needle-like crystals. 1H NMR (400 MHz, CDC1To a stirred solution of kojic acid (5 g, 35.19 mmol) in methanol (35mL) was added benzyl bromide (4.7mL, 38.7mmol) dropwise at RT. The reaction mass was heated at 100°c for 5h. The methanol in the reaction mass was distilled out. The resulting crude solids were treated with a mixture 60ml water and 6ml acetone and filtered under suction. The obtained solids were dried under high vacuum at 60°c for 1 h to afford the required compound (5.5g).

Molecular Weight:232.23
XLogP3:0.9
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:4
Exact Mass:232.07355886
Monoisotopic Mass:232.07355886
Topological Polar Surface Area:55.8
Heavy Atom Count:17
Complexity:337
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes