Search results for "beta"
showing 10 items of 3374 documents
Asymmetric synthesis of fluorinated cyclic beta-amino acid derivatives through cross metathesis.
2006
The asymmetric synthesis of several fluorinated cis-2-aminocycloalkane carboxylic acids (cis-2-ACACs) with a cross metathesis (CM) reaction as the key step has been carried out, constituting the first time a metathesis protocol has been undertaken with fluorinated imidoyl chlorides. Subsequent chemoselective hydrogenation of the olefin moiety, Dieckmann condensation, and stereoselective reduction of the iminic double bond afforded the corresponding beta-amino esters with several ring sizes. The asymmetric version of the process was achieved by using (-)-8-phenylmenthol as a chiral auxiliary.
ChemInform Abstract: Carbohydrates as Chiral Templates in the Stereoselective Synthesis of . beta.-Amino Acids
2010
pH-sensitive hydrogel based on a polyaspartamide derivative
2006
A pH-sensitive hydrogel was prepared by UV irradiation technique. Starting polymer was obtained from alpha,beta-poly (N-2-hydroxyethyl)-DL-aspartamide (PHEA) partially derivatized with glycidyl methacrylate (PHG). The PHG copolymer was cross-linked by UV irradiation in the presence of methacrylic acid (MA) to form a pH sensitive hydrogel. The cross-linked matrix shaped as microparticles was characterized by FT-IR spectrophotometry, XPS, X-ray diffraction, SEM and particle size distribution analyses. Moreover, to have information about water affinity of the prepared sample, swelling measurements were carried out in aqueous media mimicking some biological fluids. In order to employ the prepar…
NLO Polymers Containing as Active Chromophore in Dandionylpyridinium, Betaine Units: Synthesis, Modeling and Characterization
2000
In present article we report about synthesis, quantum chemical model calculations, non-linear optical characterization and dependencies of the surface potential changes on irradiation with light of novel polyurethane based polymers, namely a bipolar organic compound N-(indan-1,3-dion-2-y1)-4-N’,N’dialkylaminopyridinium betaine (IPB) containing charged electron donor and electron acceptor groups covalently bonded to polyurethane polymer backbone. These newly synthesized IPB containing polymers could be regarded as a promising thermally stable organic non-linear optical materials with long time performance for photonic applications.
Utilization of different dietary lipid sources at high level in herbivorous grass carp (Ctenopharyngodon idella): mechanism related to hepatic fatty …
2008
Herbivorous grass carp (Ctenopharyngodon idella) has been reported to exhibit low capacity to utilize high dietary lipid, but different lipid sources might affect this limited capacity. In order to compare the effects of different lipid sources with different lipid levels, juvenile grass carp were fed one of nine diets containing three oils [lard, plant oil mixed by maize and linseed oil, and n-3 high unsaturated fatty acid-enriched (HUFA-enriched) fish oil] at three lipid levels (20, 60 and 100 g kg(-1) dry diet) for 8 weeks. Decreased feed intake, poor growth performance, hepatic pathology and higher blood lipid peroxidation were found in 60 and 100 g kg(-1) fish oil groups. Conversely, i…
INTERACTION BETWEEN SODIUM NITRITE AND BETA ADRENERGIC BLOCKERS ON ISOLATED RAT AORTA
1978
Evidence for the formation of 1,3- and 1,4-dehydrobenzenes in the thermal decomposition of diaryliodonium-carboxylates
1986
Abstract Abstract: Generation of m- and p-benzynes in decomposition of diaryliodonium- 3- and 4-carboxylates is demonstrated by three-phase method.
<title>Nonlinear optical properties of some indandione-1,3 pyridinium betaine derivatives</title>
1997
In this paper nonlinear optical properties of indandione-1,3 pyridinium betaine (IPB) molecule and its novel amphiphilic derivatives have been studied. Hyper-Rayleigh scattering (HRS) has been used as a direct and accurate tool to determine effective hyperpolarizability (beta) of IPB derivatives dissolved in chloroform. Evaluation of hyperpolarizability gives an averaged values of (beta) from 140 multiplied by 10-30 to 450 multiplied by 10-30 esu. Disordering of molecular orientation for multilayer Langmuir-Blodgett films of compound C17-IPB has been studied by SHG techniques and discussed for different film thickness. It has been observed that orientation degree of the Z-type molecular str…
Über makrozwitterionen, 10. Versuche zur darstellung von makrozwitterionen aus α,ω-bifunktionellem poly(α-methylstyrol)
1975
Verschiedene Moglichkeiten zur Darstellung von Makrozwitterionen ohne polare Gruppen in der Polymerkette werden diskutiert. Unter Verwendung von 3-Dimethylaminopropyllithium als Initiator und Propansulton (2) als Kettenabbruchreagenz wurden α,ω-bifunktionelle Poly(α-methylstyrol)e 4 mit einer tert. Amino- und einer Lithiumsulfonat-Endgruppe (Molekulargewichtsbereich ≈ 103; Bifunktionalitat >90%) dargestellt. Die beiden Endgruppen wurden wie bei den entsprechenden monofunktionellen Polymeren analytisch (N,S) und spektroskopisch (IR und NMR) nachgewiesen. Obwohl die beiden Endgruppen der bifunktionellen Polymeren jeweils unabhangig in die freie Sulfonsaure-Gruppe bzw. in die Trimethylammonium…