Search results for "Adduct"
showing 10 items of 320 documents
The in vitro metabolic activation of dibenz[a,h]anthracene, catalyzed by by rat liver microsomes and examined by 32P-postlabelling.
1991
DNA has been incubated in vitro with dibenz[a,h]anthracene (DB[a,H]A) and the related 5,6-diol and 3,4-diol in the presence of 3-methylcholanthrene- or Aroclor 1254-induced rat liver microsomes. After incubation, the DNA was extracted and examined for the presence of aromatic adducts using the nuclease P1 modification of the 32P-postlabelling technique. The maps of PEI-cellulose plates and autoradiography showed that 92% of the radioactivity contained in DB[a,h]A-DNA adduct spots is derived from the related 3,4-diol and that about 50% of the adducts may be formed following the conversion of this diol to the bay-region anti- and syn-3,4-diol 1,2-oxides.
Morphological transformation and DNA adduct formation by dibenz[a,h]anthracene and its metabolites in C3H10T1/2CL8 cells.
1994
The major routes of metabolic activation of dibenz[a,h]-anthracene (DBA) have been studied in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. The morphological transforming activities of three potential intermediates formed by metabolism of DBA by C3H10T1/2 cells, trans-3,4-dihydroxy-3,4-dihydro-DBA-(DBA-3,4-diol), trans-dihydroxy-3,4-dihydro-DBA-anti-1,2-oxide (DBA-3,4-diol-1,2-oxide) and DBA-5,6-oxide were determined. DBA-3,4-diol-1,2-oxide was a strong morphological transforming agent giving a mean of 73% dishes with Type II or III foci and 1.63 Type II and III foci per dish at 0.5 microgram/ml. DBA-3,4-diol produced a mean of 42% dishes with Type II or III fo…
Reversible coordination of dioxygen by tripodal tetraamine copper complexes incorporated in a porous silica framework.
2010
The present study reports the synthesis and rational design of porous structured materials by using a templating method. A tetraethoxysilylated tripodal tetraamine (TREN) was covalently incorporated in a silica framework with a double imprint: A surfactant template and a metal ion imprint. The presence of a cationic surfactant (CTAB) endowed the material with a high porosity, and the tripodal or square-pyramidal topology of the ligand was preserved thanks to the use of the silylated Cu(II) complex. After removal of the surfactant and de-metalation, the incorporated tetraamine was quantitatively complexed by CuCl(2) and the material has shown after thermal activation that a reversible bindin…
Selective photocatalytic oxidation of 5-hydroxymethyl-2-furfural in aqueous suspension of polymeric carbon nitride and its adduct with H2O2 in a sola…
2018
Abstract This work reports a study on the reactivity of polymeric carbon nitride (PCN) and PCN-H2O2 adduct samples for sunlight photocatalytic selective oxidation reactions. The characterization of these materials was reported in a previous paper where the reactivity towards the partial oxidation of 5-hydroxymethylfurfural (HMF) was studied by using two different laboratory scale photoreactors; one irradiated by UV lamps and the other one by natural sunlight. In the present study it has been confirmed the effectiveness of these C3N4 based materials for the selective partial oxidation of HMF to FDC (2,5-furandicarboxaldehyde) in aqueous medium in a pilot plant photoreactor irradiated by natu…
Syntheses of oxygenated spongiane diterpenes from carvone. Synthesis of dorisenone C
2005
Abstract The synthesis of dorisenone C, a representative member of the spongiane-type diterpene family, is described. The synthesis follows a B→AB→ABC→ABCD approach and is based on the initial preparation of the previously known hydroxy-aldehyde 14 (AB rings) from R -(−)-carvone, followed by an intramolecular Diels–Alder reaction between an oxygenated diene moiety and an acetylenic dienophile for the construction of the C ring (compound 22 ), and adequate manipulation of the Diels–Alder adduct functionality for completion of the spongiane framework.
Cisplatin sensitivity is related to late DNA damage processing and checkpoint control rather than to the early DNA damage response
2008
The present study aimed at elucidating mechanisms dictating cell death triggered by cisplatin-induced DNA damage. We show that CL-V5B hamster mutant cells, a derivative of V79B, are hypersensitive to cisplatin-induced apoptotic death. CL-V5B cells are characterized by attenuated cisplatin-induced early (2-6 h) stress response, such as phosphorylation of stress-activated protein kinases (SAPK/JNK), ATM and Rad3-related (ATR) protein kinase, histone H2AX and checkpoint kinase-1 (Chk-1). Human FANCC cells also showed a reduced phosphorylation of H2AX and SAPK/JNK at early time point after cisplatin treatment. This was not the case for BRCA2-defective VC-8 hamster cells, indicating that the FA …
Relationship of Dibenzo[a, l]pyrene-DNA Binding to the Induction of p53, p21WAFIand Cell Cycle Arrest in Human Cells in Culture
2000
Abstract The tumor suppressor protein p53 plays an important role in recognition of DNA damage and induction of subsequent cell cycle arrest. One of its target genes encodes the p21 WAFI protein which is involved in the mediation of growth arrest after DNA damage has occured. The exceptionally potent carcino-genic polycyclic aromatic hydrocarbon (PAH) dibenzo[a, l]pyrene (DB[a, l]P) and its ultimate metabolites, the fjord region (+)-syn- and (-)-anti-11,12-diol 13,14-epoxides (DB[a, l]PDE), were used in order to investigate DNA damage via adduct formation, subsequent induction of p53 and p21 WAFI , and cell growth behavior in human mammary carcinoma MCF-7 cells. Exposure of MCF-7 cells to 0…
Photochemical ligand rearrangement in dirhodium(II) compounds. Structure of Rh2(O2CCH3)2(η2-O2CCH3)[(C6H4)PPh2] (η2-PCCl)(PCClP-ClC6H4)Ph2
1995
Abstract The photochemical reaction of the adducts Rh2(O2CCH3)3[(C6H4)P(o-ClC6H4)Ph]· (P(p-XC6H4)3) (X=H, Me, Cl), yield the compounds Rh2(O2CCH3)2(η2-O2CCH3)[(p-XC6H3)P (p-XC6H4)2](η2-PCCl), (PCCl=P(o-ClC6H4)Ph2) in a ligand rearrangement reaction that involves activation of CH and RhC bonds. The factors that favour this process are studied by carrying out photochemical reactions with different phosphines. The structures of Rh2(O2CCH3)2(η2-O2CCH3) [(C6H4)PPh2](η2-PCCl) has been determined by X-ray diffraction. Mr=1321.1, orthorhombic, space group Pbcn, a=20.339(8), b=20.07(6), c=23.07(3) A , V=9413(3) A 3 , Z=8, D x =1.86 g cm −3 . Mo Kα radiation (graphite crystal monochromator, λ=0.071…
Complexes of organometallic compounds XXVIII. The solution chemistry of bis(acetylacetone)ethylenediimine adducts of organotin(IV) halides
1971
Abstract The nature of methanol solutions of a series of bis(acetylacetone)ethylenediimine adducts of organotin(IV) halides has been studied by electronic and PMR spectroscopy and by osmometry and conductivity. Effectively complete dissociation to the free ligand and solvated organotin(IV) halide moieties is inferred.
ChemInform Abstract: Preparation of Dithiacycloalkynes by Cyclization Reactions Applying the Cesium Effect.
2010
Abstract The strained dithiacycloalkynes 3a,b and the larger heterocyclic alkynes 3c and 4 are obtained by cesium assisted cyclization reactions of the dithiols 1a–c and 1,4-dibromo-2-butyne (2). The reactivity of 3a–c was studied in cycloaddition and complexation reactions generating the adducts 5a,b and 6 and the silver and cobalt complexes 7 and 8.