Search results for "phosphorus"
showing 10 items of 431 documents
PHOSPHORORGANISCHE VERBINDUNGEN 119.1DIE ASYMMETRISCHE INDUKTION ALS MECHANISTISCHER WEGWEISER BEI DER VERESTERUNG VON METHYLPHENYL- PHOSPHINSÄURE-HA…
1989
Abstract Bei der Umsetzung von rac. Methylphenylphosphinsaure-halogenide-nund pseudohalogeniden MePhP(O)X (X = F, Cl, CN, OC6H4NO2(p)) mit Alkoholen ROH (R = Me, PhCH2, CF3CH2 und i-Prop.) in Gegenwart der optisch aktiven Amine 1 bis 5 entstehen partiell optisch aktive Ester mit einer optischen Induktion von 1 bis 14%. Ein Mechanismus, der uber funf- bzw. sechsbindige Phosphorzwischenprodukte ablauft. wird vorgeschlagen. The Reaction of rac. methylphenylphosphinicacid-halides and pseudohalides MePhP(O)X (X = F, Cl, CN, OC6H4NO2(p)) with alcohols ROH (R = Me, PhCH2, CF3CH2 and i-Prop) leads in the presence of the optically active amines 1-5 to partial optically active esters. The optical ind…
The [1,2,3]triazolo[1,5-a]pyridine ring: a sensitive sensor for the electronic profile of phosphorus substituents.
2009
The unique nature of the [1,2,3]triazolo[1,5-a]pyridine reveals without any external perturbation the electronic contribution of various substituents to the phosphorus atom in phosphines, based on the equilibrium of two possible ring-chain isomers.
Synthesis, Characterisation and Reactivity towards PdII and PtII of ortho-, meta- and para-Xylyl-Based Phosphorus-Containing Macrocycles
2002
The new meta- and para-xylyl-based phosphadithiamacrocycles 6-phenyl-6-phospha-3,9-dithiabicyclo[9,3,1]pentadeca-1(15),12,14-triene (L2) and 6-phenyl-6-phospha-3,9-dithiabicyclo[9,2,2]pentadeca-1(13),12,14-triene (L3) have been synthesised and characterised. The reactivity of these ligands and the previously described ortho-xylyl macrocycle 6-phenyl-6-phospha-3,9-dithiabicyclo[9,4,0]pentadeca-1(11), 12,14-triene (L1) with [PdCl2(cod)] and K2[PtCl4] has been studied. [MCl2(L)] complexes have been obtained and characterised by NMR spectroscopy. X-ray structural analyses have been carried out in the case of [PdCl2L2]·CH3CN (2·CH3CN) and [PdCl2L3] (3). In both compounds the PdII ion adopts a sl…
Cover Feature: Few‐layer Black Phosphorous Catalyzes Radical Additions to Alkenes Faster than Low‐valence Metals (ChemCatChem 8/2020)
2020
Stereospezifische Überführung chiraler acyclischer tertiärer Phosphinsulfide in die entsprechenden tertiären Phosphinoxide mit Dimethylsulfoxid (DMSO)
1975
Die Uberfuhrung chiraler acyclischer tertiarer Phosphinsulfide in die entsprechenden tertiaren Phosphinoxide mit DMSO in saurer Losung erfolgt unter vollstandiger Inversion der Konfiguration am zentralen Phosphoratom. Aufgrund dieses stereochemischen Verlaufs wird ein Mechanismus fur die Reaktion zur Diskussion gestellt. Stereospecific Conversion of Chiral Acyclic Tertiary Phosphine Sulfides into the Corresponding Tertiary Phosphine Oxides by Means of Dimethyl Sulfoxide (DMSO) The conversion of chiral acyclic tertiary phosphine sulfides into the corresponding tertiary phosphine oxides by means of DMSO in acidic solution proceeds with complete inversion of configuration at the central phosph…
Bis(pentamethylcyclopentadienyl)-Substituted Phosphanes: Synthesis and Structure
1998
The bis(1,2,3,4,5-pentamethyl-1,3-cyclopentadien-1-yl)phosphanes 3−7 are formed in good yields by the reaction of the halogenophosphanes 2a or 2b with the appropriate nucleophile. Following another route, the dialkylaminobis(pentamethylcyclopentadienyl)phosphanes 11a−c have been synthesized by the treatment of dichloro(dialkylamino)phosphanes with two equivalents of (pentamethylcyclopentadienyl)lithium. The compounds 3−11 have been characterized by multinuclear NMR spectroscopy and 3, 5, 6, and 11a have also been characterized by single-crystal X-ray diffraction studies. The molecular structure of 11a is governed by steric congestion, which typically would lead to a parallel arrangement of …
Phosphororganische Verbindungen, 65. Die selektive Abspaltung von Allylgruppen aus Allylphosphonium‐, ‐arsonium‐ und ‐sulfoniumsalzen und aus Allylsu…
1970
KCN spaltet Allylphosphonium-, -arsonium- und -sulfoniumsalze in Methacrylnitril und tertiare Phosphine, tertiare Arsine und Thioather auf. Durch alternierende Cyanolyse und Quartarisierung konnen Phosphonium- und Arsoniumsalze mit vier verschiedenen Liganden aufgebaut werden. Allylammoniumsalze, Allylphosphinoxide und -phosphonsaureester konnen nicht gespalten werden. Dagegen liefern Allylsulfone mit KCN in guten Ausbeuten Methacrylnitril und Sulfinsauren. Organic Phosphorus Compounds, 65. The Selective Elimination of Allyl Groups from Allylphosphonium, -arsonium and -sulfonium Salts and from Allyl sulfones by Cyanolysis KCN cleaves allylphosphonium, -arsonium, and -sulfonium salts to give…
Phosphorus Profile of Basidiomycetes
2015
Phosphorus profiles of methanolic extracts of dried basidocarps of edible and toxic mushrooms collected in Poland have been determined. Despite of the presence of standard phosphorus compounds majority of the extracts revealed the presence of phosphonates. Also, the presence of polyphospates was determined in selected cases.
Increased recovery of brain acetylcholinesterase activity in dichlorvos-intoxicated European eels Anguilla anguilla by bath treatment with N-acetylcy…
2003
Organophosphate (OP) pesticides are widely used as antiparasitic chemicals in finfish aquaculture. However, current antidotes cannot be applied to treat intoxicated fish. We showed in previous studies the importance of glutathione (GSH) metabolism in pesticide resistance of the European eel Anguilla anguilla L. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-l-cysteine (NAC) on the recovery of European eels exposed for 96 h to a sublethal concentration (0.17 mg l^-1; 20% of its 96 h LC50) of the OP pesticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate; DDVP). This insecticide and acaricide decreased muscular GSH content and increased oxidised g…
Analysis of insecticides in honey by liquid chromatography–ion trap-mass spectrometry: Comparison of different extraction procedures
2010
The feasibility of different extraction procedures was tested and compared for the determination of 12 organophosphorus and carbamates insecticides in honey samples. In this sense, once the samples were pre-treated - essentially dissolved in hot water by stirring - and before they could be analyzed by liquid chromatography-ion trap-second stage mass spectrometry (LC-MS(2)), four different approaches were studied for the extraction step: QuEChERS, solid-phase extraction (SPE), pressurized liquid extraction (PLE) and solid-phase microextraction (SPME). The main aim of this work was to maximise the sensitivity of pesticides and to minimise the presence of interfering compounds in the extract. …