Acyclic noncompetitive antagonists of ionotropic γ-aminobutyric acid (GABA) receptors, bearing an ester or ether linkage, were designed, synthesized, and assayed for their inhibition of the specific binding of [3H]4′-ethynyl-4-n-propylbicycloorthobenzoate (EBOB), a radiolabeled noncompetitive ...
Conjugate addition of primary, secondary, tertiary alkyl and phenyl lithium reagents to 2-alkenoic acids affords good yields of branched saturated carboxylic acids. Methyl groups at the α- and β-carbon of the 2-alkenoic acid decrease reactivity as acceptors, and foster deprotonation, respectiv...
The substrate range of leucine dehydrogenase and phenylalanine dehydrogenase isolated from different organisms was investigated using a range of hydrophobic α-keto acids. Several aliphatic l-amino acids with bulky side chains were synthesized by reductive amination, l-neopentylglycine was produ...
A new general approach for the synthesis of optically active α-amino acids has been developed. The key steps involve a ruthenium catalysed cross-coupling reaction to give a range of α,β-unsaturated ketones, which were then reduced to allylic secondary alcohols in the presence of a chiral CBS ...
Racemic N-benzylated-β2, β3, and β2,3-amino acid methyl esters were synthesized and submitted to hydrolysis catalyzed by lipase B from Candida antarctica in organic solvents. Good to excellent enantioselectivities were obtained for β3- and β2,3-amino acid derivatives, whereas the enzyme sho...
To date, explanations for the origin and emergence of the alphabet of amino acids encoded by the standard genetic code have been largely qualitative and speculative. Here, with the help of computational chemistry, we present the first quantitative exploration of nature's “choices” set aga...
A quinine-derived chiral anion-exchanger stationary phase was applied for the direct high-performance liquid chromatographic separation of the enantiomers of N-protected unusual β-amino acids, i.e. 3-aminobutanoic acid, 3-aminopentanoic acid, 3-amino-4-methylpentanoic acid, 3-amino-4,4-dimethyl...
Organotin compounds have been applied as stabilizers for PVCs, fungicides, and pesticides, those can enter water systems through antifouling paints on ships as well as from diverse industrial and agricultural processes. This study aims to monitor the background levels of six organotins in 200 fi...
The thermolysis of the butyltin chlorides at 200–300 °C in the liquid phase has been investigated by 1H, 13C, and 119Sn NMR spectroscopy. The stabilities follow the order: Bu2SnCl2 > Bu3SnCl > BuSnCl3. Only tributyltin chloride showed any evidence of redistribution, giving dibutyltin dichlorid...
Butyltin trichloride, as a catalyst precursor, promotes the following processes: (i) etherification of 2,3-unsaturated alcohols, (ii) etherification of functional diols, (iii) cyclization of 2,5-hexanedione, and (iv) dehydration of cyclic diols. Many examples are reported.
Butyltin compounds (BTs) are considered as endocrine disruptors or environmental hormones. It has been applied as an antifouling paint in marine vessel, and extensively in commercial, industrial and agricultural applications. In order to investigate the decomposition and accumulation of BTs in b...
This study provides an insight on a long-term butyltin pressure, spatio-temporal changes and current tributyltin distribution in the Klaipėda Port sediments. Moreover, it examines whether the restrictions on tributyltin use led to a decreased pollution in the area. Changes over a 9-year period i...
In contrast to a previous report, butyltin trichloride reacts with 1-(2-methyl-2,3-dihydrobenzothiazol-2-yl)-propan-2-one to yield a hydroxyl-bridged aquobutyldichlorotin hydroxide dimer that is hydrogen bonded to four 2-methylbenzothiazole molecules.
An accurate and precise analytical method for the determination of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) compounds has been proposed in this study. Dispersive liquid-liquid microextraction (DLLME) was used to isolate and preconcentrate the analytes from the sample matrix. So...
Several per-O-methylated monosaccharides and polysaccharides were used as models in an attempt to identify more convenient reagents for accomplishing reductive cleavage of glycosidic linkages. Included in the model studies were methyl α- and β-d-glucopyranoside, methyl α- and β-d-mannopyrano...
The objective of this study was to determine the toxic effects of butyltin trichloride (BTCl) during early pregnancy. Following successful mating, female rats were given BTCl by gastric intubation at 0, 56, 226, or 903 mg/kg on days 0–3 or 4–7 of pregnancy. Female rats were sacrificed on day 2...
We synthesized poly(poly(ethylene glycol)methyl ether methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (p(PEGMA-b-DMAEMA)) by sequential addition of monomers and its quaternized products (p(PEGMA-b-(DMAEMA-co-QDMAEMA)) from the reaction with benzyl chloride for dispersion of copper phth...
The aim of the present work is to construct and investigate the properties of novel polyelectrolyte multilayers consisting of poly(N,N-dimethylamino)ethyl methacrylate (PDMAEMA) and sodium alginate (SA). The influence of PDMAEMA’s pH dependent ionization degree on the charge balance, thickness ...
In the present work we investigated the conformations of some N-mono-substituted propanamides of general formula CH3CH2CONHR, wherein R is chosen from n-(C1C9)alkyl, cyclo(C3C6)alkyl, some branched (C3C6)alkyl or phenyl. The amides were synthesised by the well known Schotten-Baumann reacti...
A series of A-region analogues of 2-(3-fluoro-4-methylsufonamidophenyl) propanamide 1 were investigated as TRPV1 antagonists. The analysis of structure-activity relationship indicated that a fluoro group at the 3- (or/and) 5-position and a methylsulfonamido group at the 4-position were optimal f...
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