Dibenzazepine Research Articles

Putative identification of functional interactions between DNA intercalating agents and topoisomerase II using the V79 in vitro micronucleus assay

Clastogenicity is frequently observed following treatment of mammalian cells with new chemical entities. This clastogenicity, unless proven otherwise, is assumed to result from the imperfect repair of DNA lesions produced from covalent chemical/DNA interaction. However, clastogenicity can also arise via other mechanisms such as non-covalent chemical intercalation into DNA resulting in poisoning of cellular DNA topoisomerase II (topo II) and stabilization of DNA double strand breaks. We have recently reported modifications to the V79 in vitro micronucleus assay which allow an indirect evaluation of both the intercalative and topoisomerase-interactive activities of chemical agents. In the present studies we have used these modified assays to further assess the validity of this approach in an evaluation of a number of intercalating and non-intercalating polycyclic compounds. It is shown that intercalating agents may be catalytic topo II inhibitors (e.g. chloroquine (CHL), tacrine (TAC), 9-aminoacridine (9AA), ethidium bromide (EB)) or topo II poisons (e.g. proflavine (PROF), auramine O (AUR) and curcumin (CURC)). Still other intercalators are shown to lack detectable topo II-interactions, (e.g. imipramine (IMP), quinacrine (QUIN), 2-aminoanthracene (AA), iminostilbene (IMN) and promethazine (PHE)). It is concluded that (1) the clastogenicity of three agents, PROF (a typical DNA intercalating agent), and AUR and CURC (both structurally atypical intercalating agents, with unknown clastogenic mechanisms), may be due to topo II poisoning; (2) other intercalating agents may either act as catalytic topo II inhibitors or exhibit no functional topo II interaction; (3) The use of these cell-based approaches may provide a logical first step in determining if unexpected clastogenicity associated with test article exposure is due to a topo II interaction.

ChemInform Abstract: Dibenz(b,f)azepines. Part 7. Synthesis of New, Potentially CNS Active Dibenz(b,f)azepine Derivatives.

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.

ChemInform Abstract: Triplet Energy Transfer of the Intramolecular System Having Benzophenone and Dibenz(b,f)azepine at the Chain Ends: Chain Length Dependence.

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.

ChemInform Abstract: Synthesis of Dipyrazolo(3,4‐b:4′,3′‐f)azepines and Dithieno(2,3‐b:3′,2′f)azepines from 1‐Substituted 2,7‐Dichloro‐4,5‐dihydro‐1H‐azepine‐3,6‐dicarbaldehydes.

AbstractThe title compounds (V) and (VII), new bis‐heterocyclic analogues of dibenzo(b,f)azepines, are prepared via the aldehydes (III).

Effect of type and extent of crystalline order on chemical and physical stability of carbamazepine

Three crystalline phases of carbamazepine (C), namely (i) the needle-shaped form I (tempered) with high crystalline order, (ii) beam-shaped form I (anhydrate) with lower crystalline order, which was prepared by dehydration of the dihydrate, and (iii) the prismatic form III, which is stable at room temperature, were prepared and their physical properties were determined. Then they were separately mixed with 40% (w/w) colloidal silica and stored open under climatic stress at 4 temperatures (56–72°C) and 3 relative humidities (41–71%). The physial and chemical stability of C was followed for 200 days. Form I (anhydrate) transformed under all conditions to form III, with the highest rate at 51° C, while the other phases were physically stable. C degraded chemically by hydrolysis to iminostilbene (IS); about 10 mol% were formed at the highest stress after 200 days. Small amounts of secondary products were detected. An initial constant degradation rate up to 1 mol% IS was followed by a slower, again linear degradation. The initial rates of formation of IS per unit surface area of the crystals (°k, mol%/day) were highest for form I (anhydrate) and lowest to form I (tempered). The calculated Arrhenius activation energies up to 67° C were of the order form III > form I (anhydrate) > form I (tempered) with 135, 125 and 104 kJ/mol, respectively. The energies of activation for chemical degradation correlate well with the content in free enthalpy of the respective crystalline phases and their correspondent physical stability.

ChemInform Abstract: Formation of Acridine from the Reaction of Dibenz(b,f)azepine with Silver(I). Formation of an Aromatic Nitrenium Ion?

ChemInform Abstract: Formation of Acridine from the Reaction of Dibenz(b,f)azepine with Silver(I). Formation of an Aromatic Nitrenium Ion?

Synthesis and reactions of polymers with photoactive terminal groups—3. The use of radical promoted cationic polymerization for the synthesis of poly( n-butyl vinylether) with n-acyl dibenz(b, f)azepine terminal units

The free radical promoted cationic polymerization of n-butyl vinyl-ether (BVE) was achieved by the thermal decomposition of N-[4,4-azobis-(4-cyanopentanoyl)]-bisdibenz(b, f)azepine (ADBA) in the presence of diphenyliodonium hexafluorophosphate (Ph 2I +PF 6 −) or silver hexafluorophosphate (AgPF 6). Polymer samples prepared in the presence of AgPF 6 contained a significant number of terminal dibenzazepine units. Chain extension via dimerization of the dibenzazepine units occurred upon irradiating these polymers with u.v. light ( λ = 366 nm) in CH 2Cl 2 solution containing a triplet sensitizer (benzophenone or benzil). Polymer samples prepared in the presence of the iodonium salt contained only a very small fraction of macromolecules having dibenzazepine end-groups and were, therefore, not appropriate for the chain extension procedure.

Studies on the oxidation of 5H-N-substituted dibenz[b,f]azepines. III. Oxidative metabolism by rat liver microsomes.

Studies on the oxidation of 5H-N-substituted dibenz[b,f]azepines. III. Oxidative metabolism by rat liver microsomes.

Synthesis of 11-phenyl-5,6-dihydro-11H -dibenz(b,e)azepine Derivatives

Synthesis of 11-phenyl-5,6-dihydro-11H -dibenz(b,e)azepine Derivatives