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Showing 1 to 16 of 16 for “"Alpha Position"”.
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Neue optisch aktive Phosphoniumsalze als Phasentransferkatalysatoren sowie die Verwendung der korrespondierenden Phosphane in der asymmetrischen Katalyse
… found that sterically demanding substituents in alpha-position to the amide group led to the highest enantiomeric excesses, whereas the enantioselectivity dropped in case of substitution at the beta position. The highest enantiomeric excess was obtained with the methyl phosphonium iodine of …
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Pd-katalysierte asymmetrische Synthese allylischer Sulfone und Stereochemie der Lithiumsalze chiraler allylischer Alpha-tert-Butylsulfonyl-Carbanionen
… up to 98%. Deprotonation of said compounds in alpha-position to their sulfonyl-group forms alpha-tert-Butylsulfonylcarbanions, which are characterized by a hindered rotation around the alpha-C-S-bond and consequently configurative stability at appropriately low temperatures. Last-named renders …
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Guanidino-aryl substituted enol lactones: Selective and potent mechanism-based inhibitors of trypsin-like serine proteases
… tetrahydro-2-pyranone (4)) at the $\alpha$-position. The $\beta$-aryl substituted system included the 4-guanidino phenyl substituted protio and iodo enol lactones 4-(4-guanidinophenyl)-6-(methylidene) tetrahydro-2-pyranone (5) and 4-(4-guanidinophenyl)-6-(E)-iodomethylidene …
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Kontrollierte Darstellung von Blockcopolymeren durch atom transfer radical polymerization (ATRP) und Untersuchungen der Oberflächenmorphologie durch Rasterkraftmikroskopie
… with phenyl-, methyl-, and H- substituents in alpha-position of the initiating radical were investigated with respect to their initiating properties in the ATRP of styrene and MMA. PEO-b-PS and PS-b-PEO-b-PS block copolymers were synthesized by ATRP of styrene in bulk. For the first time, …
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Kinetics and mechanisms of oxidation of organic and inorganic substrates by transition metal oxo complexes
… CrO2+ involves a hydride abstraction from the [alpha]-position (primary and secondary 1,2-diols) or from the [beta]-position (pinacol). Reactions of phenols with CrO2+ produce the corresponding phenoxyl radicals in a rate-determining-step. The phenoxyl radicals are further oxidized by the …
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The synthesis and characterisation of Langmuir-Blodgett film forming TCNQ adducts.
… the short chain Z-beta-(l-butyl-4'-quinolinium)-alpha-cyano-4-styryldicyanomethanide (C[4]H[9](4)Q3CNQ) is a typical example. These zwitterionic D-pi-A materials (where D and A are electron donors and acceptors respectively) exhibit properties such as solvatochromism, molecular rectification and …
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Synthesis of Single Isomer Trisubstituted Olefins from beta-chloro-alpha-iodo-alpha, beta-Unsaturated Esters and Alkynyl Esters
… A unique olefin template such as (E)-beta-chloro-alpha-iodo-alpha,beta-unsaturated esters cross-couple with 9-alkyl-9-BBN to produce single isomer trisubstituted olefins using palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. This methodology can be further expanded to introduce various …
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Novel genotoxins that target estrogen receptor- and androgen receptor- positive cancers : identification of DNA adducts, pharmacokinetics, and mechanism
… aniline mustard was linked to estradiol at the 7[alpha] position (E2-7[alpha]), and to target AR(+) prostate cancer, the aniline mustard was linked to estradien-3-one at the 11[beta] position (11[beta]). Competitive binding experiments show that E2-7[alpha] and 11[beta] compete well with the …
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Struktur-Wirkungsbeziehungen bei der enzymatischen Hydrolyse von Carbonsäureestern
… des sp2-hybridisierten Carbonylsauerstoffatoms (alpha–Position) zu finden sind. Dazu zählen insbesondere: Acylkettenlängen mit mehr als 4 Kohlenstoffatomen, iso-, sec- oder tert-Funktionen, aromatische Ringe mit polaren Gruppen wie 2-Hydroxy-Gruppen sowie trans-Doppelbindungen.
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Computational thermochemistry of hydrocarbons, oxygenates, cyclic alkanes, and furans
… literature values. Ketone C--H BDEs in the [alpha] position decrease by 6-9 kcal mol^{-1} with increasing substitution compared to normal alkane C--H BDEs. Group additivity (GA) and hydrogen-bond increment (HBI) values for these ketones are determined. Thermodynamic parameters for …
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Hepatic Apo E mRNA Levels in BALB/c and C57BL/6 Mice Fed Different Levels and Types of Oil
… analyses identified Apolipoprotein E, P450-15-$\alpha$-hydroxylase (Cyp 2a4) and seven unique genes. Apolipoprotein E is found on most lipoproteins and binds primarily to the LDL and Apo E receptors in the liver, thereby clearing lipoproteins from the plasma. Cyp 2a4 hydroxylates testosterone, …
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Hepatic Apo E mRNA levels in BALB/c and C57BL/6 mice fed different levels and types of oil
… analyses identified Apolipoprotein E, P450-15-$\alpha$-hydroxylase (Cyp 2a4) and seven unique genes. Apolipoprotein E is found on most lipoproteins and binds primarily to the LDL and Apo E receptors in the liver, thereby clearing lipoproteins from the plasma. Cyp 2a4 hydroxylates testosterone, …
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Verfahren zur Funktionalisierung und bioaktiven Ausrüstung von Implantatoberflächen für eine verbesserte Gewebeintegration
… respectively proved the element composition and functionality corresponding to poly(aminomethyl-p-xylylene-co-p-xylylene) (AM-ppx). Zetapotential measurements confirmed the aliphatic character of the amino groups. Their suitability as anchor groups was investigated by means of an …
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Supramolecular polymer additives to improve the crystallization behavior and optical properties of polybutylene terephthalate and polyamides
… are capable to efficiently nucleate the alpha form of PA6 even at concentrations below 200 ppm, with extremely high nucleation efficiencies of around 90 %. In addition, selected derivatives were found to distinctly improve the optical properties haze and clarity, as well as the laser …
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Synthesis and reactivities of titanocene-oxo complexes and rhodium-catalyzed oxidative amidation
… of amides bearing a quaternary carbon at the alpha position from sterically hindered aldehydes and alcohols. A variety of amines, both aliphatic and aromatic, were effective nucleophiles and generated the amide products in good to excellent yields. The aldehyde substrate scope was very limited …