F:Flammable;74-96-4Relevant articles and documents
Verbascoside, synthetic derivatives and other glycosides from Argentinian native plant species as potential antitumoral agents
Garro, Hugo A.,Bruna-Haupt, Ezequiel,Cianchino, Valeria,Malizia, Florencia,Favier, Silvina,Menacho-Márquez, Mauricio,Cifuente, Diego,Fernández, Claudio O.,Pungitore, Carlos R.
, p. 4703 - 4708 (2021)
A phytochemical study was performed on three native plant species from the central-western zone of Argentina: Buddleja cordobensis Grisebach, Baccharis salicina Torr. & A. Gray and Nepeta cataria L. We could obtain verbascoside (1) from B. cordobensis. From N. cataria, we could obtain 1, 5, 9-epi-deoxyloganic acid (2) L. Finally, we could isolate 2-β-(L-rhamnopyranosyl)-3-angeloyloxy-15-acetyloxy-7,13(14)-E-dien-ent-labdane (3) and 2-β-(L-rhamnopyranosyl)-3-α-angeloyloxy-15-hydroxy-7,13(14)-E-dien-ent-labdane (4) from B. salicina. Moreover, three derivatives from 1, and one semi-synthetic derivative from 2, were prepared. PCR reaction was used to analyse the activity against DNA polymerase and cell culture to determine cytotoxicity and antitumoral activity. Verbascoside (1) was strongly active in the nanomolar scale (IC50 = 356 nM) against DNA polymerization. Moreover, verbascoside was also strongly active in the nanomolar scale against human melanoma cell line (IC50 = 256 nM) and human colorectal cell line (IC50 = 320 nM). Furthermore, derivatives 6 and 7 were cytotoxic against both cancer cell lines.
Sixma et al
, p. 127,133,139 (1956)
Reactivity of mono-halogen carbene radical anions (CHX-; X = F, Cl and Br) and the corresponding carbanions (CH2X-; X = Cl and Br) in the gas phase
Born, Monique,Ingemann, Steen,Nibbering, Nico M. M.
, p. 2537 - 2547 (1996)
The gas-phase reactions of mono-halogen substituted carbene radical anions, CHX- (X = F, Cl and Br) and the corresponding carbanions, CH2X- (X = Cl and Br) with halomethanes and organic esters have been examined with the use of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The chlorine and bromine containing (radical) anions react by SN2 substitution with the parent chloro- and bromo-methanes, whereas an SN2 and/or a BAC2 reaction occurs with the methyl ester of trifluoroacetic acid and dimethyl carbonate. The main features of the results are: (i) the SN2 substitution of a given carbene radical anion with CH3C1 or CH3Br is less efficient than this reaction of the corresponding carbanion, (ii) the radical anions react less efficiently with dimethyl carbonate than the carbanions, (iii) the SN2 substitution is less important for the radical anions than for the carbanions in the reactions with the two carbonyl compounds, (iv) for both types of ions, the BAC2 pathway becomes relatively more important as the halogen atom is changed from chlorine to bromine. These findings are discussed in terms of the thermodynamics of the overall processes in combination with considerations of the potential energy surfaces which can describe these gas-phase processes.
Young,Arch,Shyne
, p. 957 (1941)
Effects of Preferential Solvation and of Solvent-Solvent Interaction on the Rates of Nucleophilic Substitution involving Anions in Binary Mixed Solvents. Theoretical Approach
Kondo, Yasuhiko,Kusabayashi, Shigekazu
, p. 109 - 118 (1982)
Theoretical procedures for investigating rate constants and activation parameters measured in binary mixed solvents have been presented on the basis of the concept of ideal associated mixtures.In methanol+acetonitrile mixtures the behaviour of the rate constant and of activation parameters for the ethyl iodide plus bromide ion reaction were interpreted as resulting from the specific interaction of bromide ion with methanol.In methanol+NN-dimethylacetamide mixtures association complex formation between methanol and NN-dimethylacetamide makes a significant contribution to the activation parameters, and this factor must be taken into account in interpreting the observed rate behaviour.
Process for desulpherization and hydrogen recovery
-
, (2021/11/13)
A process for removing hydrogen sulfide from a sour gas stream is presented. The method oxidizes hydrogen sulfide to sulfuric acid by reducing aqueous bromine to hydrobromic acid in solution. The aqueous bromine solution does not react with hydrocarbon components common to natural gas including methane and ethane. This allows the process to both sweeten sour gas and convert its hydrogen sulfide content to sulfuric acid in a single step. In the present process, sulfuric acid is concentrated to eliminate its bromine content prior to being removed from the system, while the remaining hydrobromic acid solution is electrolyzed to regenerate aqueous bromine and produce hydrogen. Hydrobromic acid electrolysis requires less than half the energy required by water electrolysis and is an inherently flexible load that can shed or absorb excess power to balance supply and demand.
Halogen-Dependent Surface Confinement Governs Selective Alkane Functionalization to Olefins
Zichittella, Guido,Scharfe, Matthias,Puértolas, Bego?a,Paunovi?, Vladimir,Hemberger, Patrick,Bodi, Andras,Szentmiklósi, László,López, Núria,Pérez-Ramírez, Javier
supporting information, p. 5877 - 5881 (2019/02/20)
The product distribution in direct alkane functionalization by oxyhalogenation strongly depends on the halogen of choice. We demonstrate that the superior selectivity to olefins over an iron phosphate catalyst in oxychlorination is the consequence of a surface-confined reaction. By contrast, in oxybromination alkane activation follows a gas-phase radical-chain mechanism and yields a mixture of alkyl bromide, cracking, and combustion products. Surface-coverage analysis of the catalyst and identification of gas-phase radicals in operando mode are correlated to the catalytic performance by a multi-technique approach, which combines kinetic studies with advanced characterization techniques such as prompt-gamma activation analysis and photoelectron photoion coincidence spectroscopy. Rationalization of gas-phase and surface contributions by density functional theory reveals that the molecular level effects of chlorine are pivotal in determining the stark selectivity differences. These results provide strategies for unraveling detailed mechanisms within complex reaction networks.
