Réaction #94922

Équation de réaction

trimethylchlorosilane

sodium cephalothin

monosilyltrifluoroacetamide

2-thienylacetyl chloride

→

7-(di-2-thienylacetyl)amino-3-acetoxymethyl-3-cephem-4-carboxylic acid

Solvants

chloroform

—

alcohol

Conditions de réaction

Traitement

1. 1
   workup.WAITto remain at this temperature for two days
2. 2
   Autreevaporated in vacuo to a residue which
3. 3
   workup.DISSOLUTIONis dissolved in ethyl acetate (50 ml.)
4. 4
   Lavagewashed three times with water
5. 5
   SéchageThe ethyl acetate layer is dried over magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Autrethe filtrate evaporated in vacuo
8. 8
   Autreto obtained a residue
9. 9
   Autreprecipitated with hexane three times

Mode opératoire

A suspension of sodium cephalothin (1.18 g.) in anhydrous alcohol-free chloroform (10 ml.) is silylated by the addition of trimethylchlorosilane (1.1 ml.). After stirring for 30 minutes, monosilyltrifluoroacetamide (2.5 ml.) and 2-thienylacetyl chloride (2.0 ml.) are added to the suspension which is then heated to 45° C. The mixture is allowed to remain at this temperature for two days and then evaporated in vacuo to a residue which is dissolved in ethyl acetate (50 ml.) and washed three times with water. The ethyl acetate layer is dried over magnesium sulfate, filtered and the filtrate evaporated in vacuo to obtained a residue. The residue is dissolved in chloroform and precipitated with hexane three times, each time discarding the supernatent liquid. The 7-(di-2-thienylacetyl)amino-3-acetoxymethyl-3-cephem-4-carboxylic acid is obtained in a solvent-free form by freeze-drying from a solution in benzene.

Source