Search results for "amination"
showing 10 items of 1702 documents
Organic chlorine compounds in lake sediments. V. Bottom of Baikal near a pulp mill
1990
Abstract Organically bound chlorine (OCl) together with inorganic chloride (Cl − ) was measured from bottom surface samples of the Lake Baikal near a pulp mill and compared to organic matter contents (OM). Although total contents of OCl, Cl − and OM were much lower than, the ratio of OCl to OM was of the same order of magnitude as in pulp mill recipients of Finland.
A study on the aminomercuration-nucleophilic demercuration of --1,5-cyclooctadiene; stereoselective synthesis of 2,6-disubstituted-9-aza bicyclo[3.3.…
1992
Abstract The aminomercuration of cis - cis -1,5-Cyclooctadiene with a series of mercury(II) salts followed by nucleophilic displacement of mercury by aromatic amines, water and nitrate ion has been studied. As a result, bicyclic triamines, aminoalcohols and nitrate esters have been obtained respectively in clean processes which occur under total stereoelectronic control by involvement of a tricyclic aziridium ion to afford a single stereoisomer in each case. The influence of the counter ion and the basicity of the amine on the tandem aminomercuration-demercuration is discussed.
Effect of Glufosinate (Phosphinothricin) and Inhibitors of Photorespiration on Photosynthesis and Ribulose-1,5-Bisphosphate Carboxylase Activity
1992
Summary Glufosinate (phosphinothricin) irreversibly inhibits glutamine synthetase and leads to a great decrease in the amino acids glutamine, glutamate, aspartate, serine, glycine and alanine. Due to the lack of glutamate and serine, the transamination of glyoxylate into glycine in the course of photorespiration cannot take place. The inhibition of this part of the photorespiratory process plays the essential role with respect to the photosynthesis inhibition caused by PPT under atmospheric conditions. After addition of different photorespiration or Calvin cycle intermediates to phosphinothricin no decrease in photosynthesis inhibition can be measured. This suggests that photosynthesis inhi…
Silica-Immobilized NHC-Gold(I) Complexes: Versatile Catalysts for the Functionalization of Alkynes under Batch and Continuous Flow Conditions
2017
Immobilized sterically demanding NHC-Au(I) complexes silica-[(IPrR)Au]Cl and silica-[(IAdPrR)Au]Cl are synthesized and characterized. These complexes are suitable catalysts in typical homogeneous Au(I)-catalyzed alkyne reactions such as hydration, hydroamination, hydroarylation, or cycloisomerization. The results obtained with the immobilized catalysts in reactions in batch are comparable to those obtained with their homogeneous counterparts with the advantage of easily recovered and recycled in successive reactions. Their catalytic activity decreases when reused in batch reactions, probably because of crushing that is associated with magnetic stirring. In contrast, these immobilized cataly…
Triarylamines connected via phenylenevinylene segments
2003
Abstract The influences of the conjugation length and of side chains with various electronic character on the electro-optical properties of oligo(phenylenevinylene)s end-capped with diphenylamino groups are investigated. Horner-Olefinations were used for the synthesis of chromophores with 3–7 rings in the conjugated system, additionally, Pd-catalysed amination of bromo-OPVs is a useful route to introduce the end groups. Compared with the “electronically neutral” alkyl side chains, electron donating ethers and, more pronounced, electron withdrawing sulfonyl side chains shift the absorption and emission spectra to longer wavelengths. The elongation of the π-system from 3 to 5 and 7 rings has …
Mode I fracture toughness behavior of hydro-thermally aged carbon fibre reinforced DGEBA-HHPA-PES systems
2012
In this work the Mode I fracture toughness behavior of unidirectional CFRP laminates is investigated by means of Double Cantilever Beam (DCB) tests. The composite samples were manufactured by thermal curing after impregnation of a Carbon fabric with a DGEBA epoxy and anhydride HHPA curing agent. One resin batch was also mixed with a PES thermoplastic monomer to enhance the matrix toughness. Two lots of samples, toughened and un-toughened, were then left to soak in hot water to achieve various degrees of aging. The influence of matrix toughening and hydrothermal aging on the delamination behavior of the composite have then been assessed and correlated with characterization data from Dynamic …
ChemInform Abstract: Synthesis of a Naphtho-pyrido-Annulated Iodonium Salt and Pd-Catalyzed Transformation to 7H-Naphtho[1,8-bc][1,5]naphthyridine.
2014
Nitropyridylnaphthalene is the central intermediate for the synthesis of naphthonaphthyridine and benzo-δ-carboline. Whereas the Cadogan reaction gives the carboline, transformation of the nitro group to iodo followed by oxidation and cyclization results in an iodonium salt. A twofold Pd-catalyzed amination leads to the naphthyridine.
Synthesis of a Naphtho-pyrido-Annulated Iodonium Salt and Pd-Catalyzed Transformation to 7H-Naphtho[1,8-bc][1,5]naphthyridine
2013
Nitropyridylnaphthalene is the central intermediate for the synthesis of naphthonaphthyridine and benzo-δ-carboline. Whereas the Cadogan reaction gives the carboline, transformation of the nitro group to iodo followed by oxidation and cyclization results in an iodonium salt. A twofold Pd-catalyzed amination leads to the naphthyridine.
Responses of two earthworm populations with different exposure histories to chlorophenol contamination
1998
Two populations of the earthworm Aporrectodea tuberculata (Eisen), one from a chlorophenol contaminated and another from an uncontaminated site in central Finland, were exposed to acute, toxic, and sublethal concentrations of pentachlorophenol (PCP). Exposure history seemed to have only slight effect on the responses of the earthworms. Values of a lethal concentration of 50% in the humus-rich soil were very high, 1,870 μg PCP per gram for the earthworms from the contaminated site and 1,520 μg/g for the earthworms from the uncontaminated site. No differences in the accumulation of PCP from the soil into the earthworms between the two populations were found. Earthworms from both populations s…
Effects of soil organic matter content and temperature on toxicity of dimethoate toFolsomia fimetaria(Collembola: Isotomiidae)
1999
The purpose of these experiments was to study the effects of two major environmental factors, soil organic matter content (1.4–8.6%) and temperature (10–20°C), on chemical toxicity to a soil-dwelling collembolan Folsomia fimetaria. Dimethoate was used as a reference chemical. Effects on survival, reproduction, and juvenile size were investigated. Increasing soil organic matter content reduced toxicity significantly, but the differences disappeared when results were recalculated and expressed as soil pore-water concentrations. This supported the soil pore-water hypothesis. The effects of soil temperature were not so clear, because temperature affects not only the growth and reproduction of t…