نتایج جستجو برای: preparation of phenols
تعداد نتایج: 21170811 فیلتر نتایج به سال:
The aim of the paper is to present microbial transformation reactions as a step in the preparation of drugs or their key intermediates from plant derived compounds. Described are some successful applications of microbial transformation processes for preparation of steroid drugs and/or their important intermediates as well as some microbial transformations of terpenes, alkaloids, flavonoids and ...
Grape marc seeds contain large amounts of different polyphenolic compounds so they can be used for the recovery of these classes of compounds. A new green extraction method for the recovery of phenols from the grape seeds was developed. To provide a high quality extract sourced from natural product by using enzymes as alternative solvents and spending less energy, it is impeccable to call this ...
[reaction: see text]. The copper acetate mediated intramolecular O-arylation of phenols with phenylboronic acid pseudopeptides is the key step in the preparation of macrocyclic biphenyl ether hydroxamic acid inhibitors of collagenase 1 and gelatinases A and B. The intramolecular macrocyclization was found to be mild and tolerant of common chemical functionality. This methodology should provide ...
An efficient method for the preparation of various 2-substituted-1,4-benzodioxanes by CuBr-catalyzed tandem reactions of 2-((o-iodophenoxy)methyl)oxiranes with phenols has been developed. The reaction involves the ring-opening process of 2-((2-iodophenoxy)methyl)oxirane followed by an intramolecular C-O cross coupling cyclization.
A novel high-performance liquid chromatographic method with mass spectrometry and diode array detection method for the simultaneous qualitative and quantitative analysis of bioactive phenols was developed. In total, nine chemically diverse phenols including five bibenzyls, three phenanthrenes and a coumarin were unambiguously identified in Dendrobium aurantiacum var. denneanum by comparison wit...
abstract ion selective electrodes (ises) are electrochemical sensors that respond selectivity to the activity of ionic species. an ion-selective electrode is an electrochemical device that uses a thin selective membrane or film as the recognition element, and is an electrochemical half-cell equivalent to other half-cells of the zeroth (inert metal in a redox electrolyte). in common methods o...
Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of tot...
the kinetics of iodination of the phenol and substituted phenols using pyridiniumiodochloride in methanol has been studied under varying conditions. the rates show first orderkinetics each in pyridinium iodochloride and phenols. the rates of reactions are measured atdifferent temperature and activation parameters for all phenols computed. hammett plot is foundto be valid and the corrletion betw...
A series of enantioselective polycyclization reactions, catalyzed by a cationic bisphosphine gold complexes, are described. The polycyclization reactions, which employ an alkyne as an initiating group, begin with a gold-promoted 6-exo-dig cyclization and can be terminated with a variety of nucleophiles including carboxylic acids, phenols, sulfonamides, and electron-rich aryl groups. This method...
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