نتایج جستجو برای: preparation of phenols
تعداد نتایج: 21170811 فیلتر نتایج به سال:
conclusions we have developed a new, simple, and efficient method for one-pot aminoalkylation of active phenol compounds with various imines prepared from 2-aminopyrimidine and benzaldehydes in good to high yields (40%-97%). materials and methods all starting materials were purchased from merck and aldrich companies. the ir spectra were recorded on a perkin-elmer rxi infrared spectrometer. resu...
Currently, meat products processed with smoke are in great demand. It has been established that when the neck is smoked by atomization of smoking flavor, amount phenols and carbonyl compounds, resistance product to hydrolytic oxidative spoilage higher than case traditional smoking. Studying chemical composition found there no significant difference content protein, fat, sodium chloride, yield s...
Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C-H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent group...
Total phenols were determined by molecular spectmphotometry, after distillation, complexation with Caminoantipyrine and extraction into chloroform. Cyanides were also determined spectrophotometrically after distillation from the acidified samples, and complexation in moderate acidic solution with barbituric acid. The dynamic ranges were 0 100 pg L-' for total phenols and 0 30 pg L-' for cyanide...
Kinetics and stoichiometric measurements based on the reactions of stable free radicals are among the most employed procedures in the evaluation of antioxidant activities of pure compounds and complex mixtures. In the present work it is shown that initial rates of diphenyl-picryl hydrazyl (DPPH) consumption elicited by cinnamic acid derivatives are closely related to their reactivity towards pe...
Cynara scolymus L. is a medicinal plant frequently used in traditional medicine for liver diseases. The aim of this study is to evaluate the antimicrobial activity of the different parts of Artichoke. Maximum antimicrobial activity was observed with methanolic extract of bound phenols for (bract and heart) against Gram negative bacteria. The MIC values for bound phenols from heart were (63μg/ml...
tetrahydropyranylation of alcohols and phenols, acetylation of aldehydes and n-boc protection of amines are efficiently catalyzed by melamine trisulfonic acid (mtsa). all reactions were performed at room temperature in good to high yields.
Naturally occurring plant phenols such as tannic acid, quercetin, myricetin, and anthraflavic acid have been shown to inhibit the mutagenicity of several bay-region diol-epoxides of polycyclic aromatic hydrocarbons including benzo(a)pyrene (BP). The present study was designed to determine whether these plant phenols can alter epidermal cytochrome P-450-dependent monooxygenases in SENCAR mice. I...
OBJECTIVE To study the correlation of toxicity with biodegradability (BODT) in order to promote QSBR development and understand the degradation mechanism. METHODS Toxicity of substituted phenols to river bacteria was determined by the turbidities that were measured using a spectrophotometer (UV-190) at 530 nm against a blank control. The biodegradability of substituted phenols was expressed a...
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