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Reductive Process (reductive + process)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Preparation of Fused Tetracyclic Quinazolinones by Combinations of Aza-Wittig Methodologies and CuI -Catalysed Heteroarylation Processes

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2009
Juan Antonio Bleda
Abstract A number of linear quinazolinones fused to five-membered rings , benzimidazo[2,1- b]quinazolinones 8 and benzothiazolo[2,3- b]quinazolinones 10 , have been prepared from iminophosphoranes 4, derived from N -substituted o -azidobenzamides by a combination of the aza-Wittig methodology and CuI -catalysed heteroarylation. The presence of a nitrogen functionality in the N -aryl substituent of 4 promotes heterocyclization after an aza-Wittig reaction/reductive process, either across the 2-position, to afford quinazolino[2,1- b]quinazolinones 11,14, or across the 4-position, to afford the benzimidazo[1,2- c]quinazoline 16 from the initially formed 3H -quinazolin-4-one. When an acetyl group is present in the N -aryl substituent of 4, aza-Wittig reactions with isocyanates lead directly to 4-methylene-4H -3,1-benzoxazines 18; this transformation involves the initial formation of a carbodiimide, which undergoes ring-closure through the enol form of the carboxamide group and eventually an unprecedented iminobenzoxazine/methylenebenzoxazine rearrangement. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Chemical removal of PCBs from water samples under ambient conditions

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2002
Hendrik Nollet
Abstract Liquids and sludges containing polychlorinated biphenyls (PCBs) can be treated to concentrate the PCBs in a solid residue. The latter can then be handled to destroy the PCBs. In the first part of this work, procedures are explored by which 2,3,4-trichlorobiphenyl (TCB) and 2,2,,3,3,,4,5,6-heptachlorobiphenyl (HeCB) are insolubilised, flocculated and removed from the water. The results demonstrate that application of Fe(III)-oxyhydroxide precipitation permits effective and reversible co-precipitation of TCB and HeCB. Fly ash from coal-fired thermal powerplants and CaO can be used as well for the rapid removal of TCB and HeCB. In the second part of this work, rapid insolubilisation followed by the degradation of TCB and HeCB by zero-valent iron powder in anaerobic batch systems is presented. Zero-valent iron was also used for the reductive dechlorination/remediation of TCB and HeCB sorbed on the fly ash and CaO particles. Overall, this paper describes a methodology to rapidly concentrate the PCBs from water and to concomitantly detoxify them in the concentrate by a chemical reductive process under ambient conditions of pH and temperature. © 2002 Society of Chemical Industry [source]

Iron-reducing bacteria unravel novel strategies for the anaerobic catabolism of aromatic compounds

MOLECULAR MICROBIOLOGY, Issue 5 2005
Manuel Carmona
Summary Although the aerobic degradation of aromatic compounds has been extensively studied in many microorganisms, the anaerobic mineralization of the aromatic ring is a more recently discovered microbial capacity on which very little information is available from facultative anaerobic bacteria. In this issue of Molecular Microbiology, Wischgoll and colleagues use proteomic and reverse-transcription polymerase chain reaction (PCR) approaches to identify for the first time the gene clusters involved in the central pathway for the catabolism of aromatic compounds in Geobacter metallireducens, a strictly anaerobic iron-reducing bacterium. This work highlights that the major difference in anaerobic benzoate metabolism of facultative and strictly anaerobic bacteria is the reductive process for dearomatization of benzoyl-CoA. The authors propose that a new type of benzoyl-CoA reductase, comprising molybdenum- and selenocysteine-containing proteins, is present in strictly anaerobic bacteria. This work paves the way to fundamental studies on the biochemistry and regulation of this new reductive process and provides the first genetic clues on the anaerobic catabolism of benzoate by strict anaerobes. [source]