Cephalosporin cephalosporin

Also at Oxford, Abraham and Newton discovered the first cephalosporin, cephalosporin C, as a product of Acremonium chrysogenum (Cephalosporium acremonium).17 This new, sulfur-containing antibiotic was also a (5-lactam but the fused, sulfur-containing ring is a six-membered dihydrothiazine. 

The answer is a. (Hardman, pp 1086—1089.) Intolerance of alcohol (disulfiram-like reaction) has been noted only with certain cephalosporins. Cephalosporins with the methylthiotetrazole side chain have been associated with a disulfi ram-like reaction because the methyl thiotetrazole group has a configuration similar to disulfi ram, which blocks the metabolism of alcohol at the acetaldehyde step. Accumulation of acetaldehyde is associated with the symptoms. The methyl thiotetrazole side chain also results in hypopro thrombi nemia by interfering with the synthesis of vitamin K-dependent clotting factors. 

Patients allergic to penicillin may be cross-sensitive to cephalosporins. Cephalosporins (cefaclor, first-generation cephalosporin) are therefore avoided in these patients and instead macrolides (for example, erythromycin) are generally administered. Ketoconazole is an imidazole antifungal agent. 

Cephalosporins are -lactam antibiotics that block microbial cell wall synthesis. The original cephalosporin. Cephalosporin C, has only weak antibiotic activity. Therefore much more powerful second generation cephalosporins were developed by side-chain modification. Modifications at Cl are most effective but modifications at position 3 are also important so as to increase in vivo activity. Synthesis of the second generation cephalosporin cefuroxime requires the replacement of the C3 acetoxy side-chain of the precursor with a caibamate group. Chemical methods proceed via a hydroxylated intermediate which causes problems due to a tendency to lactonise at low pHs. Therefore development of a biocatalysis step was initiated in order to achieve selective reaction nnder mild conditions. 

The (PhO)3P/Cl2 reagent, prepared in situ by titrating a solution of triphenyl phosphite with chlorine, was used to convert the phenoxyacetamido cephalosporin (cephalosporin V) derivative 29 into the 7-amino derivative 30 (as an easily filterable hydrochloride) in excellent yield (Equation 3) <2004OL3885>. A 7-formamido cephalosporin was deformylated with concentrated HC1 to yield the corresponding 7-amino compound <2000BMC2317>. 

Extends the half-life of cephalosporin ° Cephalosporin given with ... 

GENERAL FEATURES OF THE CEPHALOSPORINS Cephalosporins are excreted primarily by the kidney, and dosage should be decreased in patients with renal insufficiency. Cefpi-ramide (not available in U.S.) and cefoperazone are excreted predominantly in the bUe. Cefotaxime is deacetylated to a metabolite with less antimicrobial activity than the parent compound and excreted by the kidneys. The other cephalosporins do not undergo appreciable metabolism. 

Center for Microbial oceanography research and education (c.more). http / / en.wikipedia.org/wrki/ Cephalosporin Cephalosporin. http //dinicaltrials gov/... 

The introduction of the cephalosporins was a result of investigations in the mid-1940s by Giuseppe Brotzu who discovered that Cephalosporium acremonium, isolated for a sewage outfall, inhibited the growth of several bacterial species induding Salmonella typhus. The prototype of the cephalosporins, cephalosporin C, was subsequently... 

In his cephalosporin synthesis methyl levulinate was condensed with cysteine in acidic medium to give a bicyclic thiazolidine. One may rationalize the regioselective formation of this bicycle with the assumption that in the acidic reaction mixture the tMoI group is the only nucleophile present, which can add to the ketone. Intramolecular amide formation from the methyl ester and acid-catalyzed dehydration would then lead to the thiazolidine and y-lactam rings. The stereochemistry at the carboxylic acid a-... 

---