Reacción #1339773

Ecuación de reacción

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

acetone

Jones Reagent

→

product

Rendimiento 5.0%

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

Rendimiento 5.0%

Disolventes

water

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe clear solution was cooled to +5° C. by means of an ice-bath
2. 2
   TemperaturaWhile maintaining the temperature at +5° to 10° C.
3. 3
   Temperaturawithout cooling
4. 4
   FiltraciónThe reaction mixture was filtered through a glass frit
5. 5
   Lavadothe dark-green residue washed with 500 ml of acetone
6. 6
   OtroThe filtrate was then evaporated until all of the acetone
7. 7
   Otrowas removed
8. 8
   workup.ADDITIONTo the aqueous, partly crystalline product was added 1.2 1 of methanol
9. 9
   Temperaturathis mixture was then heated to its boiling point
10. 10
    OtroThe resulting clear dark-green solution was placed in an ice-bath
11. 11
    Otroto crystallize
12. 12
    FiltraciónThe crystalline product was filtered
13. 13
    Lavadowashed with 500 ml of a cold solvent mixture
14. 14
    Otrofinally dried

Procedimiento

232 g (1 mol) of 2-(hydroxymethyl)-5-(phenylmethoxy)-4H-pyran-4-one were put into a 10 1 stirring flask containing 6.61 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° 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 hr. 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 1 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 methanol +250 ml water and finally dried. Yield: 195 g=79%. From the mother liquor a further 5% of the product could be isolated.

Fuente