Reacción #350212

Ecuación de reacción

ethyl α-carbethoxy-dithioacetate

sodium methylate

sodium methylate

chloroacetonitrile

→

2-cyano-3 -hydroxy-5-ethylthio-thiophene

Rendimiento 52.4%

Disolventes

methanol

methanol

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGThe mixture was stirred for 1 hour at 45° C. and 2 hours at 20° C.
2. 2
   workup.STIRRINGthe mixture was stirred for 4 hours at 20° C
3. 3
   OtroThe mixture was evaporated to dryness under reduced pressure
4. 4
   workup.DISSOLUTIONthe residue was dissolved in water
5. 5
   workup.ADDITIONToluene was added to the aqueous phase which
6. 6
   workup.ADDITIONwas then acidified by addition of concentrated hydrochloric acid
7. 7
   Otrothe organic phase was rapidly separated
8. 8
   Otroby decanting
9. 9
   Filtraciónvacuum filtered
10. 10
    Otrothe recovered crystals were dried

Procedimiento

192 g of ethyl α-carbethoxy-dithioacetate [Ber., Vol. 100 (1967), p. 1420] were added at 20° C. to a solution of 70 g of sodium methylate in one liter of methanol and after stirring for 5 minutes at 20° C., 76 g of chloroacetonitrile were added thereto. The mixture was stirred for 1 hour at 45° C. and 2 hours at 20° C. and after the addition of a solution of 70 g of sodium methylate in 500 ml of methanol, the mixture was stirred for 4 hours at 20° C. The mixture was evaporated to dryness under reduced pressure and the residue was dissolved in water. Toluene was added to the aqueous phase which was then acidified by addition of concentrated hydrochloric acid and the organic phase was rapidly separated by decanting. The organic phase was iced and vacuum filtered and the recovered crystals were dried to obtain 97 g of 2-cyano-3 -hydroxy-5-ethylthio-thiophene melting at 105° C. A microanalytically pure sample after crystallization from benzene melted at 105° C.

Fuente