6-Acetoxy-2H-pyran-3(6H)-one

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 2055 g of sodium hydrogen carbonate and 1004 g of sodium acetate were dissolved in a mixed solvent of 1.8 L of water and 15 L of THF. The resultant was cooled to −15° C., and 1.2 L of THF solution containing 2257 g of N-bromosuccinimide was added while maintaining the temperature at 0° C. or lower. Furthermore, 1200 g of furfuryl alcohol (Compound 1) was added while maintaining the temperature at 0° C. or lower, and agitated at the same temperature for 10 minutes. After confirming the end of the reaction by thin-layer chromatography, 299 g of DMAP and 2498 g of acetic anhydride were added while maintaining the temperature at 0° C. or lower. The reaction solution was heated to 30° C. and agitated at that temperature for 3.5 hours. After confirming the end of the reaction by thin-layer chromatography, the solution was cooled to 5° C., and added with 9.5 L of 2 N aqueous sodium hydroxide solution to prepare a solution of pH 6.5. This reaction solution was extracted with ethyl acetate and washed with a saturated sodium bicarbonate solution to obtain the organic layer. The solvent was distilled away under reduced pressure to obtain 1263 g of a crude product (±) 4 as a clear brown oily product (crude yield: 71.1%). was added while maintaining the temperature at 0° C. while maintaining the temperature at 0° C. were added while maintaining the temperature at 0° C. The reaction solution was heated to 30° C. agitated at that temperature for 3.5 hours the end of the reaction by thin-layer chromatography the solution was cooled to 5° C. to prepare a solution of pH 6.5 This reaction solution was extracted with ethyl acetate washed with a saturated sodium bicarbonate solution to obtain the organic layer The solvent was distilled away under reduced pressure

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 500 g (5.10 mol) of furfuryl alcohol (Compound 1) was dissolved in 1.65 L of water and 6.6 L of THF in a nitrogen gas stream and cooled to 0° C. or lower. To this, a mixture of 855 g (10.2 mol) of sodium hydrogen carbonate, 418 g (5.10 mol) of sodium acetate and 953 g (5.35 mol) of N-bromosuccinimide was added by spending 40 minutes. Thereafter, the resultant was agitated for an hour, and 2,083 g (20.4 mol) of acetic anhydride was added at 0° C. or lower. Then, the resultant was heated to room temperature and agitated overnight. At the end of the reaction, 20.5 L of a saturated aqueous sodium hydrogen carbonate solution was added, followed by extraction with ethyl acetate. The organic layer was dried with anhydrous sodium sulfate and subjected to vacuum concentration to obtain 776 g of a crude product (crude yield: 42.6%). The obtained crude product was subjected to column purification (n-Hex:AcOEt=3:1) to obtain 339 g of Compound (±) 4 as a yellow-brown oily product. was added agitated overnight was added followed by extraction with ethyl acetate The organic layer was dried with anhydrous sodium sulfate subjected to vacuum concentration to obtain 776 g of a crude product (crude yield: 42.6%) The obtained crude product was subjected to column purification (n-Hex:AcOEt=3:1)

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 24.0 g of 6-hydroxy-2H-pyran-3(6H)-one was dissolved in 80 ml of acetic anhydride. After cooling the solution to 0° C., 30 ml of pyridine was dropwise added thereto.