| 摘要 |
<p>The invention relates to an improved process for preparing cephalosporins by reaction compounds such as 7-amino -cephalosporanic acid, 7-amino-3-deacetoxy-cephalosporanic acid or their derivatives with derivatives of alpha -amino acids in the presence of a properly immobilized penicillin acylase enzyme under the following conditions, independently, or in combination: (1) at a temperature ranging from 0 DEG C to +20 DEG C; or (2) at ambient pH; with a high molar ratio of ( alpha -amino acid to a cephalosporanic nucleus.</p> |
