1-[[(6R,7R)-7-[[(2Z)-(2-Amino-4-thiazolyl)[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]pyridinium chloride monohydrochloride

Currently, two different methods for preparing ceftazidime are reported in the literature: The first method uses 7-aminocephalosporanic acid (7-ACA) as the starting core, reacting it with pyridine in the presence of trimethyliodosilane (TMSI) to obtain 7-APCA dihydrochloride. This dihydrochloride reacts with the active ester of the ceftazidime side chain acid to obtain ceftazidime tert-butyl ester. This tert-butyl ester is then hydrolyzed to obtain ceftazidime pentahydrate, which is mixed with sodium carbonate to prepare the injectable active pharmaceutical ingredient. The second method uses 7-phenylacetamide-3-chloromethylcephalosporanic acid p-methoxybenzyl ester (GCLE) as the starting core, reacting it with potassium iodide to obtain the ceftazidime intermediate 7-phenylacetamido-3-iodomethyl-3-cephalosporin-4-carboxylic acid p-methoxybenzyl ester. This intermediate undergoes a series of reactions, including nucleophilic substitution, with pyridine to obtain the target product. 1-[[(6R,7R)-7-[[(2Z)-(2-Amino-4-thiazolyl)[(1-carboxy-1-methylethoxy)imino]acetyl]amino]-2-carboxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-en-3-yl]methyl]pyridinium chloride monohydrochloride can be used as a raw material for the preparation of ceftazidime formulations.

6S,7R-Ceftazidime Isomer is an impurity of Ceftazidime (C244100). Ceftazidime Third generation cephalosporin antibiotic. Antibacterial.