Combination tables lactams

As previously noted, carbenicillin is the only widely used /3-lactam antibiotic for the treatment of infection caused by Ps. aeruginosa. Table 7.5 shows the MIC values of fifty strains of Ps. aeruginosa for a range of j8-lactam antibiotics. From the Table, carbenicillin is the only active drug and at the present time it is the least toxic agent with significant activity in the treatment of pseudomonas infections. It may be used alone or in combination with other antibiotics, e.g. aminoglycosides (see Table 7.1). 

The reaction has been shown to be of very broad scope with a multitude of nucleophiles Nu such as imides.23,24,29,32,33,36,37,42 amines,10,32 cyanide,25,32 hydroxide,10,32 alkox-ide,10,26,32 electron-rich isocyclic or heterocyclic aromatic compounds,28 carboxamides,31 lactams,31 ureas,31 sulfonamides,31 cyanate,31 formate (to give products with Nu = H),34 C-H acidic compounds,35 hydrazines and hydrazides,38 and sulfinates.38 The amino group NR R2 of cyclopropane-1,1-diamines and the nucleophile Nu in bicycles 8, 9 or 12, respectively, can be easily replaced with other nucleophiles Nu, such as water,10,32,33 alkoxide,10,32-34,42 Grignard compounds,27,42 amines,29,30,36,37,42,43 cyanide,29,33,42,44 hydride,34,42,44 and C-H acidic compounds39-41,43,44 (see Section 5.2.1.). Therefore, it is currently the most important method for the preparation of substituted bicyclic cyclopropylamines. The toxic and costly reagent methyl fluorosulfate can be avoided in a modified synthetic route, which instead of the fluorosulfate 5 proceeds via the corresponding tetraphenylborate, hexafluorophosphate, or (most conveniently) via the tosylate.23 The different steps of the method can often be combined in a one-pot procedure. Results are summarized in Table 3. 

Table 6-4 lists cephalosporins available in the United States in a more or less chronological order of their introduction, usually termed as generations. This has become a useful classification since newer P-lactams were introduced primarily to overcome the shortcomings of the earlier compounds. Thus later agents tended to have broader antibacterial spectra, increased resistance to P-lactamase inactivation, less toxicity, or some combination of these features. 

Amoxicillin is a penicillinase-susceptible semisynthetic penicillin that resembles ampicillin (see Table 23). It is stable in acidic pH of the stomach, and is more rapidly and completely absorbed from the gastrointestinal tract than is ampicillin, which is the major difference between the two. The antimicrobial spectrum of amoxicillin is essentially identical to that of ampicillin, with the important exception that amoxicillin appears to be less effective than ampicillin for shigellosis. Clavulanic acid is a beta-lactam structurally related to the penicillins that inactivates beta-lactamase enzymes commonly found in microorganisms resistant to penicillin. The combination of amoxicillin/clavulanic acid... 

A modular synthesis of a series of y-tum mimics was enabled by the Lewis acid-mediated reactions of enantiopnre hydroxyalkyl azides with piperidinones. This involved the preparation of enantiopnre azides 103, the side chains of which corresponded to those in natnrally occnrring side amino acids. These azides were combined with piperidinones 102 in the presence of BFs-OEta or TfOH, and the resulting imininm ethers hydrolyzed to the corresponding lactams 104 (Table 7.10). 

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