Modulation of penicillin acylase properties via immobilization techniques: one-pot chemoenzymatic synthesis of Cephamandole from Cephalosporin C

The modulation of penicillin G acylase (PGA) properties via immobilization techniques has been performed studying the acylation of 7-aminocephalosporanic acid with R-mandelic acid methyl ester. PGA from Escherichia coli, immobilized onto agarose activated with glycidol (glyoxyl-agarose), has been used for the design of a novel one-pot synthesis of Cephamandole in aqueous medium and without isolation of intermediates, through three consecutive biotransformations catalyzed by D-amino acid oxidase, glutaryl acylase and PGA.

Bis-trimethylsilylcefamandole: an unusually stable trimethylsilyl-intermediate

The preparation of crystalline bis-trimethylsilylcefamandole (7) and its utility in the preparation and purification of cefamandole are described. Although stable to solvolysis in isopropyl alcohol, 7 underwent smooth conversion to cefamandole in the presence of water, methanol, or ethanol.

Orally active esters of cephalosporin antibiotics. II. Synthesis and biological properties of the acetoxymethyl ester of cefamandole

The synthesis of the acetoxymethyl (AOM) ester of cefamandole (CM) is described. The sparingly soluble ester is shown to be well absorbed orally by mice, but only when administered in solution in a partially non-aqueous vehicle, 50% propylene glycol. Neither the ester in aqueous suspension nor the sodium salt of CM in solution is well absorbed orally. The rate of oral absorption of the ester from solution is very rapid as shown by the early peak time and shape of the plasma level curve. Oral bioavailability from solution is at least 60% and is apparently limited only by hydrolysis or precipitation of a variable portion of the ester dose in the intestinal lumen prior to absorption.

Orally active esters of cephalosporin antibiotics. 3. Synthesis and biological properties of aminoacyloxymethyl esters of 7-[D(-)-mandelamido]-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-3-cephem-4-carboxylic acid

The synthesis of six amino acid acyloxymethyl esters of cefamandole (1), a semisynthetic broad-spectrum cephalosporin antibiotic, is described. These esters were examined as potentially useful orally active antibiotic prodrugs. When tested for oral efficacy against Streptococcus pyogenes C203 in mouse protection tests, the esters were not notably more active than lithium cefamandole. Further studies demonstrated that significant blood and urine levels of 1 were not obtained after dosing 2a, 2b, and 2f orally at 17 mg/kg in mice. A study of the stability to chemical hydrolysis and the possible relationship of hydrolysis to the lack of oral absorption of these esters is also presented.