تفاعل #94973

معادلة التفاعل

trimethylchlorosilane

sodium cephalothin

monosilyltrifluoroacetamide

2-thienylacetyl chloride

→

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

المذيبات

chloroform

—

alcohol

ظروف التفاعل

المعالجة

1. 1
   workup.WAITto remain at this temperature for two days
2. 2
   أخرىevaporated in vacuo to a residue which
3. 3
   workup.DISSOLUTIONis dissolved in ethyl acetate (50 ml.)
4. 4
   غسيلwashed three times with water
5. 5
   تجفيفThe ethyl acetate layer is dried over magnesium sulfate
6. 6
   ترشيحfiltered
7. 7
   أخرىthe filtrate evaporated in vacuo
8. 8
   أخرىto obtain a residue
9. 9
   أخرىprecipitated with hexane three times

الإجراء التجريبي

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 obtain 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.

المصدر