反应详情

温度

5 °C

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.

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