反応 #4203

反応方程式

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

acetone

Jones reagent

→

product

収率 5.0%

4-Oxo-5-(phenylmethoxy)-4H-pyran-2-carboxylic acid

収率 5.0%

溶媒

water

反応条件

後処理

1. 1
   温度The clear solution was cooled to +5° C. by means of an ice bath
2. 2
   温度While maintaining the temperature at +5° C. to 10° C.
3. 3
   workup.STIRRINGStirring
4. 4
   温度without cooling
5. 5
   ろ過The reaction mixture was filtered through a glass frit
6. 6
   洗浄the dark green residue washed with 500 ml of acetone
7. 7
   その他The filtrate was then evaporated until all of the acetone
8. 8
   その他was removed
9. 9
   workup.ADDITIONTo the aqueous, partly crystalline product was added 1.2 l of methanol
10. 10
    温度this mixture was then heated to its boiling point
11. 11
    その他The resulting clear dark green solution was placed in an ice bath
12. 12
    その他to crystallize
13. 13
    ろ過The crystalline product was filtered
14. 14
    洗浄washed with 500 ml of a cold solvent mixture
15. 15
    その他finally dried

実験手順

232 g (1 mol) of 2-(hydroxymethyl)-5-(phenylmethoxy)-4H-pyran-4-one was put into a 10 l stirring flask containing 6.6 l of acetone and 400 ml of water. The clear solution was cooled to +5° C. by means of an ice bath. While maintaining the temperature at +5° C. to 10° C., 640 ml of Jones reagent (202 g CrO3, 600 ml water, 174 ml H2SO4) was added dropwise over a period of 1 hour. Stirring was continued for 2 hours without cooling. The reaction mixture was filtered through a glass frit and the dark green residue washed with 500 ml of acetone. The filtrate was then evaporated until all of the acetone was removed. To the aqueous, partly crystalline product was added 1.2 l of methanol, and this mixture was then heated to its boiling point. The resulting clear dark green solution was placed in an ice bath and the product allowed to crystallize. The crystalline product was filtered and washed with 500 ml of a cold solvent mixture consisting of 250 ml of methanol +250 ml of water and finally dried. Yield: 195 g. From the mother liquor, a further 5% of the product could be isolated.

出典