反应详情

温度

-20 °C

A suspension of 3.80 g (10 mmols) of 7β-phenoxyacetamido-3-methylthio-ceph-3-em-4-carboxylic acid in 38 ml of absolute methylene chloride is stirred with 4.45 ml of dimethylaniline and 1.50 ml of dimethyldichlorosilane for 30 minutes at room temperature. The reaction mixture is cooled to -20° C., 2.60 g of phosphorus pentachloride are added, the mixture is stirred for 30 minutes at -20° C. and is then added dropwise to a mixture, cooled to -20° C., of 15.5 ml of n-butanol and 1.47 ml of dimethylaniline. The temperature is allowed to rise to -10° C. and 15.5 ml of dioxane and 0.53 ml of water are added. When crystallisation starts, the pH value is adjusted to 4.1 with tributylamine and crystallisation is brought to completion by stirring for 2 hours at 0°-5° C. The precipitate is filtered off, washed with 10 ml of dioxane and 5 ml of methylene chloride and dried in a high vacuum. 7β-Amino-3-methylthio-ceph-3-em-4-carboxylic acid of melting point 205° C. (decomposition) is obtained; UV spectrum (0.1 N NaHCO3): λmax =293 (ε=7600); IR spectrum (nujol): characteristic bands at 3.15, 5.55 6.17 and 6.53μ.

1. additionis then added dropwise to a mixture
2. customto rise to -10° C.
3. customWhen crystallisation
4. customthe pH value is adjusted to 4.1 with tributylamine and crystallisation
5. stirringby stirring for 2 hours at 0°-5° C
6. filtrationThe precipitate is filtered off
7. washwashed with 10 ml of dioxane and 5 ml of methylene chloride
8. customdried in a high vacuum