A number of actinocin amides containing residues of aza-15-crown-5 and aza-18-crown-6 where crown fragments were separated from the heterocyclic chromophore by the residues of ω-amino acids were obtained as actinomycin D models.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

papaverine and its derivatives react with p-chlorophenacyl bromide to give the corresponding quaternary salts, which are converted into pyrrolo[2,1-a]isoquinolines by the action of bases.

N-Methylcarbazole-3-carboxylic acid was synthesized from N-methyl-2-amino-4-carboxydiphenylamine through the corresponding diazo compound by a modified Pschorr procedure. The acid was converted into N-methylcarbazole-3-carbonyl chloride which was treated with amines containing benzo- and aza-crown ether moieties, as well as with 3-(dimethylamino)propylamine, to obtain the respective N-substituted amides.

The formation of complexes of DNA with actinocin derivatives containing crown groups at the alpha-and/or beta-carboxy group was investigated by the spectrophotometry, spectropolarimetric titration, viscometry, and dynamic birefringence techniques. The binding constants and numbers of binding sites on DNA for the investigated compounds were determined, and changes in the macromolecular parameters of DNA in complexes with compounds containing crown groups in different positions with respect to the actinocin chromophore were investigated at various ionic strengths. The results obtained make it possible to understand the role of the crown group in the interaction of the investigated compounds with DNA; models for the binding of these compounds with the DNA double helix were proposed.

Complexes of DNA with benzocrown derivatives of actinocin were studied by viscometry and dynamic birefringence. Changes in the macromolecular structure of DNA caused by complex formation were determined. Models of DNA binding to the studied compounds were suggested on the basis of data obtained. The intercalation of actinocin chromophore of benzocrown derivatives of actinocin was shown to occur only when benzocrown groups were bound to the chromophore via the glycine spacer. A change of the distance between the crown group and the chromophore prevented ligand intercalation. Increase of the ionic strength resulted in appearance of a new, nonintercalative binding mode for crown-containing compounds determined by interaction of the crown groups with DNA.

The results of studies on the structure of complexes of DNA with compounds based on the actinocin chromophore, a center of binding of the antitumor antibiotic actinomycin D to DNA, were analyzed. In positions 1 and 9 of the chromophore of these compounds, pentapeptide lact ones of actinomycin D are replaced by groups of various origin. By using spectral, optical, and hydrodynamic methods a model of binding to DNA for each compound was constructed, and some regularities of complex formation depending on the structure of actinocin substituents and the amount of ligands in the complex were revealed.

Complexes of DNA with actinocin derivatives containing benzocrown groups at positions 1 and/or 9 of the chromophore were studied by spectrophotometric titration and circular dichroism. The actinocin chromophore and the crown fragments are the DNA-binding sites of the ligands. The mode of ligand–DNA binding is shown to depend on the size of the crown group, its distance to the actinocin chromophore, and the ionic strength of the medium. Na+-selective benzocrown fragments combine with DNA phosphate groups. The simultaneous interaction of the actinocin chromophore with the DNA bases is possible only at an optimal distance between the two binding sites of ligand molecule.

Complexes of DNA with actinocin derivatives containing ω-dialkylaminoalkyl groups in the1 and/or 9 positions of the chromophore were studied by spectrophotometric titration, circular dichroism, and viscometry. Induced circular dichroism (ICD) spectra of the DNA-ligand complexes were compared for the cases of the complexes of known structure established by other methods. It was shown that the presence of an isoelliptic point in the long-wavelength absorption band of the ICD spectra of the ligand under monomeric binding conditions could indicate intercalation of the actinocin chromophore into DNA. The separation of the cationoid center and the chromosphore upon elongation of the methylene chain increases the aggregability of the ligand pn the surface of the DNA double helix, which prevents the intercalation of the chromophore.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Electron absorption, luminescence excitation, and emission spectra of 8-butylcabramoyl-, 8-cyclohexylcarbamoyl-, s-dodecylcarbamoyl-, and 8-octadecylcarbamoyl-1-(3-dimethylaminopropylcarbamoyl)2-amino-4-methyl-3H-phenoxazin-3-ones were studied in aqueous media with different pH values, in 2-propanol, and in octane. The compounds were presumed to exist as equilibrium mixtures of several forms. The highest fluorescence quantum yield was observed for alkaline aqueous solutions and solutions in nonpolar solvent where the predominant form is characterized by smaller number of intramolecular hydrogen bonds, A procedure was proposed for quantitative estimation of the overall donor-acceptor effect of the alkylamino groups in compounds existing in solution as equilibrium mixtures of several forms.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.