Publisher Summary This chapter presents nomenclature of actinomycins (AMs) based on the peptide structure, which uses International Union of Pure and Applied Chemistry–International Union of Biochemistry (IUPAC–IUB) rules for naming peptide analogs. AMs are well-known as specific inhibitors of DNA-primed RNA synthesis and are used as a biochemical tool in numerous investigations on cellular events, especially macromolecular biosynthesis and virus replication. The clinical use of actinomycin is in the treatment of Wilms' tumor, gestational choriocarcinoma, and mixed metastatic embryonal carcinoma of the testis. The chapter has compiled microbiological procedures for actinomycin preparation and chemical methods for modification of AM and for total synthesis. Analogs and derivatives of known structure have been listed. The chapter also describes structure-activity relationships in the AMs that can at present be deduced from approximately 30 peptide analogs that have been isolated from natural sources or produced by directed biosynthesis or by chemical synthesis. The crystal structure of AM and solution conformations from nuclear magnetic resonance (NMR) and circular dichorism (CD) studies have been discussed.

Structure-activity relationships in the actinomycins.

Oxidative cross-coupling reactions of substituted o-aminophenols were catalyzed by a commercial laccase to produce non-symmetrically substituted phenoxazinones for the first time. Identification by 1H-, 13C- and 31P-NMR, and by HPLC-PDA and HPLC-MS/MS of exclusively two kinds of substituted phenoxazinones out of four potential heterocyclic frameworks was confirmed by a DFT study. The redox-properties of the substrates, their relative rates of conversion and the rigid docking of selected substrates led to a revisited mechanistic pathway for phenoxazinones biosynthesis. Our suggestions concern both the first formal two-electron oxidation by laccase and the first intermolecular 1,4-conjugated addition which secures the observed regioselectivity.

Non-symmetrically substituted phenoxazinones from laccase-mediated oxidative cross-coupling of aminophenols: an experimental and theoretical insight.

Synthesis of some simple actinomycin analogs

Equilibrium Solubility and Solvent Effect Study of 3-Nitrosalicylic Acid in Different Monosolvents Covering Temperatures from 278.15 to 323.15 K

The effect induced by introducing electron captor substituent, namely, fluorine in the arene rings of phenoxathiin on the structure of the phenoxathiin nucleus have been studied using the ab initio method at the B3LYP/(6-31+G)+d basis set level. The study predicts and analyses the configuration of several not yet synthesized fluorinated-phenoxathiin derivatives. Thus, the magnitude of change in the puckering angle Φ c of phenoxathiin was found to be dependent on the position of the fluorine atom with respect to the oxygen atom of the central heterocyclic ring. Substitution at the 1-position, meta to the oxygen did induce flattening of the nucleus i.e. increased Φ c , while substitutions at the 2- and 4- positions, para and ortho to the oxygen, respectively, induced further puckering on the nucleus i.e. decreased Φ c . Successive substitution at these positions enhanced these effects. Thus, 1,9-difluorophenoxathiin was found to be the most flattened, while 2,3,4,6,7,8-hexafluorophenoxathiin was found to be the most puckered fluorinated phenoxathiins. The predicted inversion barrier for all the studied compounds was very small; it did not exceed 1.67 kcal/mol for the most puckered isomer. Consequently, we anticipated these compounds to enjoy an easy butterfly interconversion.

M. T. Wu

Papers

Synthesis of some simple actinomycin analogs

Synthesis of some derivatives of 4-phenoxathiinearboxylie acid