55633-19-7Relevant articles and documents
Influence of substrate structure on PGA-catalyzed acylations. Evaluation of different approaches for the enzymatic synthesis of cefonicid
Terreni, Marco,Tchamkam, Joseph Gapesie,Sarnataro, Umberto,Rocchietti, Silvia,Fernandez-Lafuente, Roberto,Guisan, Jose M.
, p. 121 - 128 (2007/10/03)
The influence of the substrate structure on the catalytic properties of penicillin G acylase (PGA) from Escherichia coli in kinetically controlled acylations has been studied. In particular, the affinity of different β-lactam nuclei towards the active site has been evaluated considering the ratio between the rate of synthesis (vs) and the rate of hydrolysis of the acylating ester (vhl). 7-Aminocephalosporanic acid (7-ACA) and 7-amino-3-(1-sulfomethyl-1,2,3,4-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (7-SACA) showed a good affinity for the active centre of PGA. The enzymatic acylation of these nuclei with R-methyl mandelate has been studied in order to evaluate different approaches for the enzymatic synthesis of cefonicid. The best results have been obtained in the acylation of 7-SACA. Cefonicid (8) was recovered from the reaction mixture as the disodium salt in 65% yield and about 95% of purity. Furthermore, through acylation of 7-ACA, a "one-pot" chemo-enzymatic synthesis was carried out starting from cephalosporin C using three enzymes in sequence: D-amino acid oxidase (DAO), glutaryl acylase (GA) and PGA. Cefonicid disodium salt was obtained in three steps, avoiding any intermediate purification, in 35% overall yield and about 94% purity. This approach presents several advantages compared with the classical chemical processes.
One-pot chemoenzymatic synthesis of 3'-functionalized cephalosphorines (cefazolin) by three consecutive biotransformations in fully aqueous medium
Justiz,Fernandez-Lafuente,Guisan
, p. 9099 - 9106 (2007/10/03)
We illustrate a new chemoenzymatic synthesis of cefazolin from cephalosporin C, involving three consecutive biotransformations in full aqueous medium. This one-pot three-step synthesis includes the D-amino acid oxidase catalyzed oxidative deamination of the cephalosporin C side chain, hydrolysis of the resulting glutaryl derivative catalyzed by glutaryl acylase, and the final penicillin G acylase (PGA)-catalyzed acylation of 7- aminocephalosporanic acid (1, 7-ACA). The product, 7-[(1H-tetrazol-1- yl)acetamido]-3-(acetoxymethyl)-Δ3-cephem-4-carboxylic acid (5), was used as an intermediate for cefazolin synthesis by 3'-acetoxy group displacement with 2-mercapto-5-methyl-1,3,4-thiadiazole. Very high yields have been achieved with all the enzymatic reactions performed; high product concentrations were obtained in short reaction times. This synthetic approach presents several advantages when compared with the conventional chemical processes. The use of the toxic reagents and chlorinated solvents is avoided, while the substrate specificity and chemoselectivity of the enzymes makes reactive group protection and intermediate purification unnecessary. The enzymatic deacylation of cephalosporin C was performed by the simultaneous use of D-amino acid oxidase and glutaryl acyclase. The substrate specificity of PGA allowed the acylation of 7-ACA (1) to be performed without purification from the glutaric acid produced during the enzymatic deacylation. These results were achieved by optimization and correct assembly of the different biotransformations involved. Special attention has been applied to the kinetically controlled acylation reaction. High yields were obtained through a careful selection of the enzyme catalyst, experimental conditions, and synthetic strategy.
