Search

The association of heteroaromatic ligands with DNA is an important and biologically relevant process, because it may have a strong influence on the function of the nucleic acid. As a result, efficient and selective DNA-targeting ligands are considered as promising lead structures for drugs. In this context, we established the quinolizinium ion as a versatile building block for the design of DNA-binding ligands, with the long-term goal to evaluate and understand the structural parameters that govern the association of cationic hetarenes with DNA. In this account we demonstrate that annelated quinolizinium derivatives are easily available and that their structure and substitution pattern are highly variable. Most notably, the availability of several derivatives with different size and shape enables the assessment of structure–property relationships regarding their DNA-binding properties. It is shown with exemplary case studies that the systematic variation of the ligand structure, along with analysis of the binding parameters, can be employed to analyze the structural requirements of a ligand to bind to different DNA forms, such as triplex, quadruplex and abasic site-containing DNA. 1 Introduction 2 Association of Quinolizinium Derivatives with Double-Stranded DNA 3 Association of Quinolizinium Derivatives with Triplex DNA 4 Association of Quinolizinium Derivatives with Quadruplex DNA 5 Association of Quinolizinium Derivatives with Abasic Positions in DNA 6 Conclusion

An improved preparation of 1,7-dimethylnaphthalene is presented, which is used as a precursor for the synthesis ofdiazoniahexacyclic salts, namely, 4a,14a-diazoniaanthra[1,2-a]anthracene (3) and 13a,16a-diazoniahexaphene (7). The influence of the reaction conditions on the formation of these isomers was investigated. Notably, the selectivity of the reactions depends significantly on the acid employed in the cyclization step. Both compounds exhibit similar absorption and fluorescence emission properties. Compound 3 exhibits a remarkable photopersistence in the solid state and in air-saturated aqueous solutions. However, diazoniahexaphene 7 undergoes rapid photodegradation in solution. X-ray diffraction analysis reveals that compound 3 adopts a helicene structure in the crystalline state.

The arylation of readily available benzo(b)quinolizini- um-9-boronic acid with carbocyclic or heterocyclic bromoarenes in the presence of a palladium catalyst (Pd(dppf)Cl2·CH2Cl2 or Pd(PPh3)2Cl2) gives the corresponding cationic biaryl products in yields of 15-81%. All aryl-substituted benzo(b)quinolizinium (acridizinium) derivatives exhibit a long-wavelength absorption maximum between 409 and 422 nm in water, which change margin- ally in different solvents (Dl

Science of Synthesis: Houben-Weyl Methods of Molecular Transformations is the entirely new edition of the acclaimed reference series Houben-Weyl, the standard synthetic chemistry resource since 1909. This new edition is published in English and will comprise 48 volumes published between the years 2000 and 2008. Science of Synthesis is a quality reference work developed by a highly esteemed editorial board to provide a comprehensive and critical selection of reliable organic and organometallic synthetic methods. This unique resource is designed to be the first point of reference when searching for a synthesis strategy. Features: * Contains the expertise of presently 450 leading chemists worldwide. * Critically evaluates the preparative applicability and significance of the synthetic methods. * Discusses relevant background information and provides detailed experimental procedures For full information on the Science of Synthesis series, visit the Science of Synthesis Homepage Series Editors: D. Bellus, S. V. Ley, R. Noyori, M. Regitz, E. Schaumann, I. Shinkai, E. J. Thomas, B. M. Trost, P. J. Reider