Anthracyclines structures

In the present scenario of protection of product development rights, it is expected that a large number of new products, based on the basic anthracycline structure, will be developed for anti-tumom trials. While basic radiation chemistry may not differ significantly fi om what we already know, it will be very interesting to know how the redox properties change with new structures [88], The most important characteristics for either anti-tumom action or toxicity is the redox potential values. We should be able to put substituents at will to have a desired redox potential of the substrate. This is extremely important from the research point of view. However, no concerted efforts have been made in this direction. 

Complex C-glycosides based on disaccharide and anthracycline structures have been elaborated by [4+2]cycloaddition reactions as outlined in Scheme 28. ... 

Daunorubicin is an anthracycline that is sometimes referred to as an antitumor antibiotic. Daunorubicin inserts between base pairs of DNA to cause structural changes in DNA however, the primary mechanism of cytotoxicity is the inhibition of topoisomerase II. The pharmacokinetics are best described by a two-compartment model, with a terminal half-life of about 20 hours. The predominant route of elimination of daunorubicin and hydroxylated metabolites is hepatobiliary... 

Alkylating agents are compounds capable of reacting covalently with DNA bases. If a compound of this type contains two reactive groups, intramolecular or intermolecular crosslinking of the DNA double helix and bending of the double strand occurs. Examples of this type shown here are cyclophosphamide and the inorganic complex cisplatin. Anthracyclines such as doxorubicin (adriamy-cin) insert themselves non-covalently between the bases and thus lead to local alterations in the DNA structure (see p. 254 B). 

The anthracycline antibiotics are fermentation products of Streptomyces peucetius. Daunorubicin (Cerubidine) is used to treat acute leukemias, while its structural analogue, doxorubicin (Adriamycin) is extensively employed against a broad spectrum of cancers. Although... 

Idarubicin (Idamycin) differs from its parent compound, daunorubicin, by the absence of the methoxy group in the anthracycline ring structure. Its mechanisms of action and resistance are similar to those of doxorubicin and daunorubicin however, it is more lipophilic and more potent than these other anthracy-clines. Idarubicin undergoes extensive hepatic metabolism and biliary excretion. Adverse reactions of idarubicin are similar to those of its congeners. 

Anthracyclines are antitumor quinone containing antibiotics produced by different strains of Streptomyces. Some of them, such as adriamycin doxorubicin), and daunorubicin are broad spectrum antitumor compounds. They act by binding to DNA and interfering with DNA replication and gene transcription. Their limitations for clinical use are cardiac toxicity and drug resistance phenomena. Consequently, intense structure-activity relationship studies have been performed to improve the pharmacological profile as well as to enhance the affinity for DNA. In particular, a number of fluorinated anthracyclines have been prepared with introduction of fluorine atoms into D or A cycles, and into the aglycone side chain linked atC-14. ... 

The anthracycline antibiotics, which include doxorubicin, daunorubicin, bleomycin, and mitomycin C, inhibit DNA and RNA synthesis. Doxorubicin also interfers with topoisomerase II (a DNA gyrase), the activity of which is markedly increased in proliferating cells. Structurally related to doxorubicin are epirubicin and mitozantrone. The cytotoxic antibiotics are used to treat leukaemias and lymphomas and also for solid tumours in the breast, lung, thyroid and ovary. Cardiotoxicity is the major dose-limiting factor, with arrhythmias and myocardial depression (Bacon and Nuzzo 1993). The chronic phase of cardiotoxicity is a dose-dependent cardiomyopathy that leads to congestive heart failure in 2-10% of patients. Myocardial injury is the result of oxygen free radical formation. Children are particularly sensitive to these cardiotoxic reactions and may require a heart transplant in their later years. Epirubicin is less cardiotoxic than doxorubicin. 

Anthracyclines isolated from stieptomyces show a 2,3,6-trideoxy-3-amino-L-/yxo-configurated sugar oc-attached to the aglycon. Therefore, the first interest centered on the synthesis of aminodeoxy sugars in the l-lyxo series, e.g., daunosamine [46-50]. Several new glycosides were prepared [51] in order to evaluate structure-activity relationships. 

A number of anthracycline antibiotics, e.g. doxorubicin (Figure 3.56) from Streptomyces peuceticus and daunorubicin from S. coeruleoru-bicus, have structurally similar tetracyclic skeletons and would appear to be related to the tetracyclines. There are similarities in that the molecules are essentially acetate derived, but for... 

K. Suzuki, G. A. Sulikowski, R. W. Friesen, and S. J. Danishefsky, Application of substituent-controlled oxidative coupling of glycals in a synthesis and structural corroboration of ciclamycin 0 New possibilities for the construction of hybrid anthracyclines, J. Am. Chem. Soc., 112 (1990) 8895-8902. 

Aromatic polyketides are structurally diverse, often polycyclic molecules that are derived from unreduced polyketone chains. This group of compounds is produced with the help of type II polyketide synthase (PKS), a complex of enzymes that catalyzes the iterative decarboxylative condensation of malonyl-CoA extender units with an acyl starter unit [70], The carbon framework of aromatic polyketides is further decorated with different functionalities, and carbohydrates are often one of them. Their presence has profound effects on physico-chemical and biological properties of aromatic polyketides. For example, anthracycline aglycones are stable and unpolar, while polyglycosylated anthracyclines are quite polar and often... 

Temperini C, Messori L, Orioli P et al (2003) The crystal structure of the complex between a disaccharide anthracycline and the DNA hexamer d(CGATCG) reveals two different binding sites involving two DNA duplexes. Nucleic Acids Res 31 1464—1469... 

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