Reacción #54388

Ecuación de reacción

potassium hydroxide

7β-phenoxyacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid benzyl ester

7β-phenoxyacetamido-3-methoxy-ceph-3-em-4-carboxylic acid benzyl ester

sodium chloride

→

7β-phenoxyacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid

Disolventes

tetrahydrofurane

methylene chloride

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGThe mixture is stirred for a further 5 minutes at 0° C.
2. 2
   workup.STIRRINGthe whole is stirred vigorously
3. 3
   Otroto separate into two phases
4. 4
   OtroThe methylene chloride phase is separated off
5. 5
   Lavadothe aqueous phase is washed with a further 30 ml of methylene chloride
6. 6
   workup.ADDITIONare added
7. 7
   workup.STIRRINGthe mixture is thoroughly shaken
8. 8
   OtroAfter separating off the organic phase
9. 9
   Extracciónthe aqueous phase is extracted twice more with 30 ml of methylene chloride at a time
10. 10
    SecadoThe combined methylene chloride extracts are dried over sodium sulphate
11. 11
    Concentraciónconcentrated by evaporation in vacuo
12. 12
    OtroThe resulting white foam crystallises on addition of chloroform and diethyl ether

Procedimiento

15 ml of pre-cooled 0.1 N potassium hydroxide solution are added, whilst stirring, to a solution prepared at 0° C., of 454 mg (1 mmol) of an approx. 3:1 mixture of 7β-phenoxyacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid benzyl ester and 7β-phenoxyacetamido-3-methoxy-ceph-3-em-4-carboxylic acid benzyl ester in 30 ml of tetrahydrofurane. The mixture is stirred for a further 5 minutes at 0° C., 100 of ice water and 100 ml of pre-cooled methylene chloride are then added and the whole is stirred vigorously. Addition of a little saturated aqueous sodium chloride solution causes the mixture to separate into two phases. The methylene chloride phase is separated off and the aqueous phase is washed with a further 30 ml of methylene chloride. The aqueous phase is covered with 50 ml of methylene chloride, 10 ml of 2 N hydrochloric acid are added and the mixture is thoroughly shaken. After separating off the organic phase, the aqueous phase is extracted twice more with 30 ml of methylene chloride at a time. The combined methylene chloride extracts are dried over sodium sulphate and concentrated by evaporation in vacuo. The resulting white foam crystallises on addition of chloroform and diethyl ether and gives 7β-phenoxyacetamido-3-methoxy-ceph-2-em-4α-carboxylic acid of melting point 142° C. (decomposition). IR spectrum (KBr): characteristic bands at 5.65, 5.75 and 5.95 μ.

Fuente