Specific removal of chlorine from the ortho-position of halogenated benzoic acids by reductive dechlorination in anaerobic enrichment cultures

1992 ◽  
Vol 100 (1-3) ◽  
pp. 273-280 ◽  
Author(s):  
Jan Gerritse ◽  
Bernard J. Woude ◽  
Jan C. Gottschal
Keyword(s):  
Reductive Dechlorination ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Enrichment Cultures

Enrichment and isolation of a reductively debrominating bacterium from the burrow of a bromometabolite-producing marine hemichordate

1995 ◽  
Vol 41 (7) ◽  
pp. 637-642 ◽  
Author(s):  
Charles C. Steward ◽  
Terry C. Dixon ◽  
Yung Pin Chen ◽  
Charles R. Lovell
Keyword(s):  
Electron Donors ◽  
Ortho Position ◽  
Enrichment Cultures ◽  
Bacterium Strain

An anaerobic 2,4,6-tribromophenol debrominating bacterium, strain DSL-1, was isolated from enrichment cultures inoculated with sediment from the burrows of the bromoaromatic-producing marine hemichordates Balanoglossus aurantiacus and Saccoglossus kowalewskyi. DSL-1 preferentially removed ortho-position bromines, resulting in the transient appearance of 2,4-dibromophenol and accumulation of 4-bromophenol. Cell-free extracts and partially purified reductive debrominase preparations from DSL-1 also debrominated 2,4,6-tribromophenol, yielding 2,4-dibromophenol and 4-bromophenol. Both NADH and NADPH stimulated 2,4,6-tribromophenol reduction by partially purified debrominase. These data are consistent with a reductive debromination mechanism. The organic cosubstrate(s) and specific electron donors used by DSL-1 in vivo are currently unknown.Key words: dehalogenation, bromometabolites, bromophenols, hemichordates.

Photoreaktionen 2-sulfinylsubstituierter Benzaldehydeeine neue photoinduzierte Sauerstoff-Transfer-Reaktion / Photoreactions of 2-Sulfinyl Substituted Benzaldehydes aNew Photoinduced Oxygen-Transfer Reaction

1976 ◽  
Vol 31 (12) ◽  
pp. 1658-1661 ◽  
Author(s):  
Reinhard Lüdersdorf ◽  
Klaus Praefcke
Keyword(s):  
Oxygen Atom ◽  
Oxygen Transfer ◽  
Redox Reaction ◽  
Transfer Reaction ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Photochemical Conversion ◽  
New Type ◽  
Substituted Benzaldehydes ◽  
Sulfinyl Group

The photochemical conversion of 2-sulfinyl substituted benzaldehydes into benzoic acids in a new type of redox reaction is discribed in which a transfer of an oxygen atom, originally attached to sulphur, takes place by insertion into the C-Η bond of the aldehyde function located in ortho position. Influences of substituents at the sulfinyl group in this photoreaction which seems to be limitated to aldehydes are discussed briefly.

scholarly journals Analysis of the Gas Phase Acidity of Substituted Benzoic Acids Using Density Functional Concepts

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1631
Author(s):  
Jorge A. Amador-Balderas ◽  
Michael-Adán Martínez-Sánchez ◽  
Ramsés E. Ramírez ◽  
Francisco Méndez ◽  
Francisco J. Meléndez
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Chemical Potential ◽  
Fukui Function ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Functional Theory ◽  
Resonance Effects ◽  
Gas Phase Acidity ◽  
Substituted Benzoic Acids

A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZC6H4COOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase ΔacidG° values obtained were close to the experimental ones reported in the literature. The good relationship between the ΔacidG° values and the electronegativity of ZC6H4COOH and its fragments, suggested a better importance of the inductive than polarizability contributions. The balance of inductive and resonance contributions of the substituent in the acidity of substituted benzoic acids showed that the highest inductive and resonance effects were for the -SO2CF3 and -NH2 substituents in the para- and ortho-position, respectively. The Fukui function confirmed that the electron-releasing substituent attached to the phenyl ring of benzoic acid decreased the acidity in the trend ortho > meta > para, and the electron-withdrawing substituent increased the acidity in the trend ortho < meta < para.

scholarly journals Metagenomic- and Cultivation-Based Exploration of Anaerobic Chloroform Biotransformation in Hypersaline Sediments as Natural Source of Chloromethanes

2020 ◽  
Vol 8 (5) ◽  
pp. 665
Author(s):  
Peng Peng ◽  
Yue Lu ◽  
Tom N.P. Bosma ◽  
Ivonne Nijenhuis ◽  
Bart Nijsse ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Reductive Dechlorination ◽  
Electron Donors ◽  
Natural Source ◽  
Hypersaline Lake ◽  
Reductive Dehalogenase ◽  
Enrichment Cultures ◽  
Cobalamin Biosynthesis ◽  
Abiotic Control ◽  
Hypersaline Sediments

Chloroform (CF) is an environmental contaminant that can be naturally formed in various environments ranging from forest soils to salt lakes. Here we investigated CF removal potential in sediments obtained from hypersaline lakes in Western Australia. Reductive dechlorination of CF to dichloromethane (DCM) was observed in enrichment cultures derived from sediments of Lake Strawbridge, which has been reported as a natural source of CF. No CF removal was observed in abiotic control cultures without artificial electron donors, indicating biotic CF dechlorination in the enrichment cultures. Increasing vitamin B12 concentration from 0.04 to 4 µM in enrichment cultures enhanced CF removal and reduced DCM formation. In cultures amended with 4 µM vitamin B12 and 13C labelled CF, formation of 13CO2 was detected. Known organohalide-respiring bacteria and reductive dehalogenase genes were neither detected using quantitative PCR nor metagenomic analysis of the enrichment cultures. Rather, members of the order Clostridiales, known to co-metabolically transform CF to DCM and CO2, were detected. Accordingly, metagenome-assembled genomes of Clostridiales encoded enzymatic repertoires for the Wood-Ljungdahl pathway and cobalamin biosynthesis, which are known to be involved in fortuitous and nonspecific CF transformation. This study indicates that hypersaline lake microbiomes may act as a filter to reduce CF emission to the atmosphere.

Photoreaktionen 2.2'-dihalogensubstituierter Benzoinether und Benzildimethylmonoketale in Lösung1 / Photoreactions of 2,2'-Dihalogen Substituted Benzoin Ether and Benzildimethylmonoketals in Solution1

1978 ◽  
Vol 33 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Claudia Bak ◽  
Klaus Praefcke
Keyword(s):  
Benzoic Acid ◽  
Electron Impact ◽  
Uv Irradiation ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Reaction Behavior ◽  
Thiobenzoic Acid ◽  
Acid Esters

Abstract The synthesis of α,α'-dihalogenated benzoin ether 6 and benzildimethylmonoketals 7 are discribed. Their reaction behavior under UV irradiation and electron impact conditions are discussed in comparison with those of arylesters 1 of seleno and thiobenzoic acid. The photoproducts of 6 and 7 are separated and identified with help of column or vaporphase chromatography. Photoinduced α-cleavages of 6 and 7 produce 2-halogenbenzoyl radicals 9 and a-monomethoxybenzyl radicals 10 or α,α-dimethoxybenzyl radicals 15 resp., which undergo four different stabilization reactions under formation of 1) 2-halogenbenzaldehydes 12 from 9 by hydrogenabstraction, 2) 2,2'-dihalogenbenzils 11 and 1,2-di(2-chlorophenyl)-1,2-dimethoxyethan (13) via dimerization of 9 or 10 resp., 3) methylesters 16 of 2-halogen-benzoic acids by β-elimination of methylradicals from 15, and 4) 2-halogenacetophenones 17 via combination of 9 with methylradicals from 15. In addition to these photoproducts 2-phenylbenzoic acidester 18, benzaldehyde (19), and acetophenone (20) are formed by photosubstitution of halogens in benzaldehydes 12 as well as in acetophenones 17 against hydrogen and in benzoic acid-esters 16 against phenyl resp. Independent photoexperi-ments prove 1) the formation of 2-phenylbenzoic acidester 18 by halogen-phenylreplace-ment in 16 and 2) that chlorine is easier than bromine, both in ortho-position to a carboxyl function, substituted by phenyl. No photoproducts {e.g. 8 or 14) are formed by substitution of halogen in the 2-halogenbenzoyl part of a-cleavage against neither a-monomethoxybenzyl nor a,a-dimethoxybenzylradicals resp. as expected like the photoinduced formation of selenoxanthones or thioxanthones 2 from selenol-or thiolesters 1.

Anaerobic transformation kinetics and pathways of chlorophenols in fresh water lake sediment

1997 ◽  
Vol 36 (6-7) ◽  
pp. 99-105 ◽  
Author(s):  
S. Susarla ◽  
Y. Yonezawa ◽  
J. Nakanishi ◽  
S. Masunaga
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fresh Water ◽  
Reductive Dechlorination ◽  
Ortho Position ◽  
Transformation Kinetics ◽  
Water Lake ◽  
Degradation Rates ◽  
Chlorine Removal ◽  
Fresh Water Lake

The reductive dechlorination of six dichlorophenol (DCP) isomers was examined in a fresh water sediment collected from Kasumigaura lake in Japan. Short lag periods were observed for all the DCPs examined varying between 1–20 days. The relative degradation rates of six DCP isomers were 2,5- &gt; 2,4- &gt; 2,3- &gt; 2,6- &gt; 3,5- &gt; 3,4- DCP with half- lives of ranging between 7-39 days. The specificity of chlorine removal indicated a preference for ortho-chlorine removal for dichlorophenol isomers substituted at ortho position, while meta and meta/para chlorine removal was observed for 3,5- and 3,4-DCP, respectively. Intermediate products of transformation, 2-, 3- and 4-MCP and phenol were identified with a combination of gas chromatography and mass spectrometry using standards.

scholarly journals Synthesis of procaine analogues containing pentafluoroethoxy groups in the aromatic nucleus

2021 ◽  
pp. 64-72
Author(s):  
I.I. Gaidarzhy ◽  
◽  
L.A. Motnyak ◽  
B.V. Kunshenko
Keyword(s):  
Mass Spectrometry ◽  
13C Nmr Spectroscopy ◽  
Amino Group ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Anesthetic Activity ◽  
Local Anesthetic Activity ◽  
Structural Analogue ◽  
Benzene Nucleus ◽  
Structural Analogues

In order to synthesize procaine analogs containing one or two pentafluoroethoxy groups, a method for the synthesis of benzoic acids containing a pentafluoroethoxy group in the ortho-position of the benzene nucleus has been developed. An effective method for the synthesis of procaine structural analogues containing one or two pentafluoroethoxy groups has been proposed. It has been shown that the replacement of the amino group by the pentafluoroethoxy group in the procaine molecule leads to a significant increase in the local anesthetic activity of the obtained compounds. The most active compound was a structural analogue of procainamide containing two pentafluoroethoxy groups in positions 2 and 4. The formation of fluorine-containing analogues of procaine was confirmed by 1H, 19F and 13C NMR spectroscopy and mass spectrometry.

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