Reacción #93186

Ecuación de reacción

6-cyano-3,4-dihydro-2,2-dimethyl-trans-3-bromo-4-hydroxy-2H-benzo[b]pyran

sodium hydride

2-Pyrrolidone

sodium hydride

6-cyano-3,4-dihydro-2,2-dimethyl-3,4-epoxy-2H-benzo[b]pyran

→

title compound

Rendimiento 60.0%

6-Cyano-3,4-dihydro-2,2-dimethyl-trans-4-(2-oxo-1-pyrrolidinyl)-2H-benzo[b]pyran-3-ol

Rendimiento 60.0%

Disolventes

Water

dimethylsulphoxide

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroresulted
2. 2
   Otrocrystallisation of the product after which it
3. 3
   Temperaturawas cooled in ice
4. 4
   Filtraciónfiltered under suction
5. 5
   OtroCrystallisation from ethanol (20 ml)

Procedimiento

A solution of 6-cyano-3,4-dihydro-2,2-dimethyl-trans-3-bromo-4-hydroxy-2H-benzo[b]pyran (4 g, 14.2 mM) in dimethylsulphoxide (20 ml) was stirred and sodium hydride (60% dispersion in oil, 0.6 g, 15 mM) added. The suspension was stirred for 1 hour when a solution of 6-cyano-3,4-dihydro-2,2-dimethyl-3,4-epoxy-2H-benzo[b]pyran resulted. 2-Pyrrolidone (1.8 g, 21 mM) and further sodium hydride (0.8 g, 21 mM) were introduced and the mixture stirred at room temperature for an additional 16 hours. Water (40 ml) was slowly added to the mixture to induce crystallisation of the product after which it was cooled in ice and filtered under suction. Crystallisation from ethanol (20 ml) gave the title compound as a cream coloured solid in 60% yield. Recrystallisation from ethyl acetate afforded the pure product as needles, m.p. 226.5°-227.5° having an nmr spectrum and t.l.c. characteristics identical to those of the compound of Description 6.

Fuente