반응 #4203

반응 방정식

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

acetone

Jones reagent

→

product

수율 5.0%

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

수율 5.0%

용매

water

반응 조건

후처리

1. 1
   온도The clear solution was cooled to +5° C. by means of an ice bath
2. 2
   온도While maintaining the temperature at +5° C. to 10° C.
3. 3
   workup.STIRRINGStirring
4. 4
   온도without cooling
5. 5
   여과The reaction mixture was filtered through a glass frit
6. 6
   세척the dark green residue washed with 500 ml of acetone
7. 7
   기타The filtrate was then evaporated until all of the acetone
8. 8
   기타was removed
9. 9
   workup.ADDITIONTo the aqueous, partly crystalline product was added 1.2 l of methanol
10. 10
    온도this mixture was then heated to its boiling point
11. 11
    기타The resulting clear dark green solution was placed in an ice bath
12. 12
    기타to crystallize
13. 13
    여과The crystalline product was filtered
14. 14
    세척washed with 500 ml of a cold solvent mixture
15. 15
    기타finally dried

실험 절차

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.

출처