تفاعل #54388

معادلة التفاعل

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

المذيبات

tetrahydrofurane

methylene chloride

ظروف التفاعل

المعالجة

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
   أخرىto separate into two phases
4. 4
   أخرىThe methylene chloride phase is separated off
5. 5
   غسيلthe 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
   أخرىAfter separating off the organic phase
9. 9
   استخلاصthe aqueous phase is extracted twice more with 30 ml of methylene chloride at a time
10. 10
    تجفيفThe combined methylene chloride extracts are dried over sodium sulphate
11. 11
    تركيزconcentrated by evaporation in vacuo
12. 12
    أخرىThe resulting white foam crystallises on addition of chloroform and diethyl ether

الإجراء التجريبي

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.

المصدر