80072-86-2

7-β-Thien-2-yl-acetamido-3-[(4-nitro-3-carboxyphenyl)thiomethyl]-3-cephem-4-carboxylic acid (CENTA) is a yellow chromogenic β-lactamases (BL) substrate. It hydrolyses readily in the presence of all BL and is therefore suitable for kinetic studies, the detection of BL enzymes in crude extracts and chromatographic fractions. CENTA is commercially available at a high price because of the cumbersome synthetic protocol, the only currently available for its preparation. Here we describe a new efficient and improved process for the preparation of CENTA. Starting from the easily available 7-aminocephalosporanic acid (7-ACA) through a three-step synthesis, CENTA was obtained with a 75% overall yield. The newly developed process proceeds through a pivotal intermediate in cephalosporin chemistry, which may be used as starting compound for the development of new cephalosporin derivatives.

Metallo-β-lactamases (MBLs) are a growing threat to the use of almost all clinically used β-lactam antibiotics. The identification of broad-spectrum MBL inhibitors is hampered by the lack of a suitable screening platform, consisting of appropriate substrates and a set of clinically relevant MBLs. We report procedures for the preparation of a set of clinically relevant metallo-β-lactamases (i.e., NDM-1 (New Delhi MBL), IMP-1 (Imipenemase), SPM-1 (Sa?o Paulo MBL), and VIM-2 (Verona integron-encoded MBL)) and the identification of suitable fluorogenic substrates (umbelliferone-derived cephalosporins). The fluorogenic substrates were compared to chromogenic substrates (CENTA, nitrocefin, and imipenem), showing improved sensitivity and kinetic parameters. The efficiency of the fluorogenic substrates was exemplified by inhibitor screening, identifying 4-chloroisoquinolinols as potential pan MBL inhibitors.

CENTA, a chromogenic cephalosporin, is readily hydrolyzed by β-lactamases of all classes except for the Aeromonas hydrophila metalloenzyme. Although it cannot practically be used for the detection of β-lactamase-producing strains on agar plates, it should be quite useful for kinetic studies and the detection of the enzymes in crude extracts and chromatographic fractions.

What are disclosed are cephalosporin derivatives of the formula formulations containing such cephem derivatives suitable for the detection of beta-lactamases, process for the manufacture of the cephem derivatives and the formulations, and use of the cephe