Antibiotics erythromycin

Before leaving ionic liquids it is worth mentioning their potential value in separation processes. Organic solvents are frequently used in multiphase extraction processes and pose the same problems in terms of VOC containment and recovery as they do in syntheses, hence ionic liquids could offer a more benign alternative. Interesting applications along this line which have been studied include separation of spent nuclear fuel from other nuclear waste and extraction of the antibiotic erythromycin-A. 

The hydroxy groups in natural products like, for example, the macrolide antibiotics erythromycin, 1"1 and desmycosin, 2001 2011 as well as the 3-(hydroxymethyl)-2- or 3-cephems 2021 and derivatives of the amino sugar garamin 2031 have been converted into the carbamate function with CDI and amines. In the case of aminoglycoside antibiotics of the sisomicin series, thiocarbamates or dithiocarbamates have been prepared from alcohols or thiols using ImCSIm and amines.12041... 

Preoperative colon preparation Intestinal antisepsis Oral antibiotics Erythromycin-neomycin... 

Facing the challenge of synthesizing the antibiotic erythromycin A la, Woodward s group took advantage of a cyclic system to achieve diastereofacial selectivity, the so-called cyclic approach.3 This approach was taken to deal with the common problem of low diastereoselectivity associated with acyclic substances. 

Let us consider Woodward s synthesis of erythronolide A -the aglycone of the antibiotic erythromycin A- which was published posthumously [2]. 

Fig. 4.9 Structures of the macrolide antibiotics, erythromycin (monobasic) and azithromycin (dibasic).

Another example of solid phase DOS involves post-modification of the natural product macrolide antibiotic erythromycin (34) [77]. Erythromycin was first converted to analogue 32 which resembles a third generation macrolide antibiotic with high activity against resistant strains (ABT-773, 35), but is attached to solid phase-bound amino acids by reductive amination. Two further reductive amination steps and cleavage from solid support form a library of compounds of type 33 (Fig. 10). 

A4 inhibitors - Patients receiving cytochrome P450 3A4 inhibitors, such as macrolide antibiotics (erythromycin and clarithromycin), antifungal agents (ketoconazole, itraconazole, and miconazole), or cyclosporine or vinblastine should not receive doses of tolterodine greater than 1 mg twice/day (greater than 2 mg/day for ER capsules). 

Carbamazepine also can induce the enzymes that metabolize other anticonvulsant drugs, including phenytoin, primidone, phenobarbital, valproic acid, clonazepam, and ethosuximide, and metabolism of other drugs the patient may be taking. Similarly, other drugs may induce metabolism of carbamazepine the end result is the same as for autoinduction, and the dose of carbamazepine must be readjusted. A common drug-drug interaction is between carbamazepine and the macrolide antibiotics erythromycin and trolean-domycin. After a few days of antibiotic therapy, symptoms of carbamazepine toxicity develop this is readily reversible if either the antibiotic or carbamazepine is discontinued. 

Antibiotics erythromycin erythromycin estolate minocycline hydrochloride tetracycline hydrochloride... 

The polyketides are a large family of bio synthetically related NPs, some of which have very great pharmaceutical value (polyketide sales total about 10 billion annually, see also Chapter 7). Some antibiotics (erythromycin, monensin, rifamycin), immunosuppressants (rapamycin), antifungal substances (amphotericin), antiparasitic (aver-mectin) and anticancer drugs (doxorubicin) are polyketides. The term polyketide refers to the fact that the basic carbon skeleton is not a simple hydrocarbon chain as in the case of fatty acids but is a series of linked keto groups in sequence (Figure 3.6). The first phase of this pathway, the generation of carbon skeleton diversification. 

In his 1956 article in Perspectives in Organic Chemistry , the late Professor R. B. Woodward characterized the macrolide antibiotic erythromycin as a synthetic challenge which is ... quite hopelessly complex, especially in view of its plethora of asymmetric centers 70). Twenty-five years after making this dismal prognosis,... 

The risk of myopathy appears to be increased by high levels of HMG-CoA reductase inhibitory activity in plasma. Lovastatin is metabolized by the CYP isoform 3A4. Certain drugs, that share this metabolic pathway can raise the plasma levels of lovastatin and may increase the risk of myopathy. These include cyclosporine, itraconazole, ketoconazole and other antifungal azoles, the macrolide antibiotics erythromycin and clarithromycin, HIV protease inhibitors, the antidepressant nefazodone, or large quantities of grapefruit juice (greater than 1 quart daily)... 

A 26-kb gene cluster encoding enzymes for synthesis of the blue antibiotic actinorhodin by Streptomyces coelicolor has been cloned and sequenced.332337 The three large 10-kb genes required for formation of the broad-spectrum antibiotic erythromycin by Saccharopolyspora erythraea have also been cloned and sequenced.337 339 In both cases, the genes... 

Figure 21-11 Catalytic domains within three polypeptide chains of the modular polyketide synthase that forms 6-deoxyerythronolide B, the aglycone of the widely used antibiotic erythromycin. The domains are labeled as for fatty acid synthases AT, acyltransferase ACP, acyl carrier protein KS, 3-ketoacyl-ACP synthase KR, ketoreductase DH, dehydrase ER, enoylreductase TE, thioesterase. After Pieper et al.338 Courtesy of Chaitan Khosla.

The macrolide antibiotic erythromycin together with statins enhances the risk of rhabdomyolysis (SED-13, 1328) (112), as do clarithromycin and azithromycin (113). 

As an example, consider the preparation of the antibiotic erythromycin A (Fig. 1). The total chemical synthesis of erythromycin was first completed in R. B. Woodward s laboratory in 1981. It took 49 people and 49 steps, and resulted in an overall yield of <0.02% relative to starting material [1-3], In contrast, a lone bacterium can make a molecule of erythromycin A in a matter of seconds a liter of such bacteria can provide up to 100 mg of erythromycin in a matter of... 

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