Isolation Of Deacetyl Cephalosporin C And Synthesis Of Related Compounds

Deacetyl cephalosporin C (DAC), a by-product, generated in the process of Cephalosporin C (CPC) fermentation, is about 15~20% of total amount of CPC. It not only pollutes the environment but also wastes the resources, due to the waste drainage contained DAC being discharged in the downstream process for purification of CPC. DAC, similar to CPC in structure, contains theβ-lactam ring. The hydroxymethy group at C-3 makes it much easier to synthesize some semi-synthetic cephalosporins. Therefore, if DAC is isolated from the waste drainage and converted to a key intermediate for some cephalosporins through its structur modification,this would be not only beneficial to the environment protection but the reduction of the cost of CPC as well.DAC in the waste drainage was adsorbed on the powdery activated carbon under acidic condition, followed by desorption with 13%(V/V) ethanol, 80% DAC purity elutate was obtained, and the isolated yield of DAC was 75%. While it was eluted with 13%(V/V) isopropanol, the eluate purity was 82%, and the isolated yield of DAC was 80%.Also, the grained activated carbon of coal with a size distribution of 10 to 50 mesh was employed as adsorbent to separate DAC from the waste drainage, and the operation was carried out in a fixed bed. The eluate purity was 85% when the adsorbent was eluted with 8%(V/V) ethanol solution, and the yield of DAC was 60~65%. After the eluate was concentrated by Nanofilter membrane, it was passed through a column packed with the resin of Amberlite IRA67, a weakly basic ion-exchange resin on which DAC was adsorbed. The desorption was carried out with 0.5mol/L sodium acetate buffer, the eluate of above 95% purity and of above 30g/L DAC was obtained. The yield of DAC was 90~95%. Addition of acetone or ethanol to this eluate, the crystal of DAC sodium was formed. The activity of activated carbon could be recovered by means of a method of saturating it with a strong basic solution contained isopropanol and then neutralizing and rinsing it with acidic solution.DAC can be converted to deacetyl glutaryl-7-ACA (D-Gl-7-ACA) in 75% yield by immobilized D-amino acid oxidase(DAAO) using DACNa as substrate. The residue ofα-keto-adipyl-deacetyl 7-ACA remained in the DAAO reaction solution may be further converted stoichiometrically by external addition of H2O2, the yield of D-Gl-7-ACA was increased to 82%. Then immobilized glutaryl-7-ACA acylase (GA)...