نتایج جستجو برای: bromosuccinimide
تعداد نتایج: 378 فیلتر نتایج به سال:
A manganese(II) complex of 2,2’-bipyridine (bipy) was synthesized and characterized by X-ray diffraction, IR, and UV-vis spectroscopy. The activity of the complex was tested for oxidation of benzyl alcohols using t -BuOOH as an oxidant in organic solvents and in an organic/water biphasic system (hexane/H2O, toluene/H2O). The effect of solvent, temperature, oxidant, and some additives (KBr, N(C ...
Acid hydrolysis revealed the constituent amino acids of brevistin as follows: aspartic acid (D-form 2, L-form 1), L-threonine (1), glycine (1), sum of L-valine and L-isoleucine (1), [L-phenylalanine (1), L-tryptophan (1), and 2, 4-diaminobutyric acid (D-form 1, L-form 1). The constituent fatty acid was elucidated to be anteisononanoic acid by gas chromatography-mass spectrometry. A lactone link...
Nucleophilic addition to alkynes represents an attractive approach to the synthesis of olefins. Obstacles to this strategy include the low reactivity of alkynes toward many organometallic reagents and difficulties associated with controlling the regioselectivity of addition. Here we demonstrate that Fe(III) salts are effective precatalysts for the carbometalation of alkynes. Primary and seconda...
α-Galactosidase from Penicillium purpurogenum was induced to a greater extent in the culture medium by arabinose, galactose, lactose and guar galactomannan. The enzyme was purified by acetone precipitation and DEAE-Sephacel column chromatography. The purified enzyme showed a single band in both native-PAGE and SDS-PAGE. The molecular mass of enzyme was found to be between 107 and 110 kDa. The e...
Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinim...
A series of general and selective Pd(II)-catalyzed Heck reactions were investigated under mild reaction conditions. The first protocol has been developed employing an imidazole-based secondary phosphine oxide (SPO) ligated palladium complex (6) as a precatalyst. The catalytic coupling of aryl halides and olefins led to the formation of the corresponding coupled products in excellent yields. A v...
The breitfussins are halogenated natural products whose structures were determined with the assistance of atomic-force microscopy. The site selectivity of N-bromosuccinimide-mediated bromination of a model breitfussin core was found to be strongly dependent on solvent selection; use of acetone led to oxazole bromination, and use of a pyridine-containing mixture led to pyrrole bromination. This ...
N-Acetylneuraminate lyase produced by Escherichia coli was purified and crystallized from a genetically engineered strain (E. coli SF8/pNAL1). The enzyme showed apparent molecular masses of 105,000 Da on gel filtration and 35,000 Da on SDS/PAGE, suggesting that the enzyme is a trimer. The apparent optimum pH and temperature were found to be 6.5-7.0 and 80 degrees C respectively. The Km values f...
Asymmetric oxidation of 1,2-diols using N-bromosuccinimide in the presence of chiral copper catalyst
a copolymer of styrene and methyl styrene was synthesized by nitroxide - mediated “living” free radical polymerization )nmp). n-bromosuccinimide was used as a brominating agent to obtain a copolymer with bromine as its end group. this brominated copolymer was used as macro initiators for atom transfer radical polymerization (atrp). chemical modifcation of the clay and transformation of...
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