Reacción #83733

Ecuación de reacción

water

(R)-2-hydroxy-3-methoxycarbonyl-2-penten-4-olide

p-nitrobenzenesulphonyl chloride

N-methylmorpholine

→

(R)-2-(4-nitrobenzenesulphonyloxy)-3-methoxycarbonyl -2penten-4-olide

Disolventes

toluene

toluene

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroare metered in at from 0 ° to 5° C
2. 2
   Otrothe toluene product phase is removed
3. 3
   Extracciónthe aqueous phase is re-extracted twice with 100 ml of toluene
4. 4
   LavadoThe toluene phases are washed with sodium chloride solution and with water
5. 5
   Filtraciónfiltered over a small amount of silica gel
6. 6
   Concentraciónconcentrated by evaporation
7. 7
   OtroThe residue is crystallised from ethyl acetate/cyclohexane
8. 8
   Otro[α]D20 =+12.4° (3% in CHCl3), m.p. 123°-124° C.

Procedimiento

34.44 g of (R)-2-hydroxy-3-methoxycarbonyl-2-penten-4-olide are dissolved in 170 ml of toluene at 40° C., 49.4 g of p-nitrobenzenesulphonyl chloride in 160 ml of toluene are added and the whole is cooled to 5° C. Within a period of 30 minutes, 20.3 g of N-methylmorpholine are metered in at from 0 ° to 5° C. 350 ml of water are added, the toluene product phase is removed, and the aqueous phase is re-extracted twice with 100 ml of toluene. The toluene phases are washed with sodium chloride solution and with water, filtered over a small amount of silica gel and concentrated by evaporation. The residue is crystallised from ethyl acetate/cyclohexane. [α]D20 =+12.4° (3% in CHCl3), m.p. 123°-124° C.

Fuente