نتایج جستجو برای: unsaturated compounds
تعداد نتایج: 241045 فیلتر نتایج به سال:
Structures and reactions of a stable dialkylsilylene and various cyclic and acyclic disilenes, which we have recently synthesized, are discussed in detail. The stable silylene was found to be well protected sterically from dimerization but least perturbed electronically as evidenced by UV–vis and NMR spectroscopy. Persilylated acyclic and cyclic disilenes have shown interesting features in the ...
1. The ferment-inhibiting action of the serum is due to the presence of compounds of the unsaturated fatty acids. 2. These fatty acid compounds may be removed from the serum by means of chloroform or ether. 3. Soaps prepared by saponifying the chloroform or ether extracts inhibit the action of trypsin. 4. The anti-enzyme action of the serum can be removed by filtering acid serum through kaolin,...
Padina sanctae-crucis Børgesen is distributed worldwide in tropical and subtropical seas; belongs to the Dictyotaceae family, and has proven to be an exceptional source of biologically active compounds. Four compounds were isolated and identified, namely: dolastane diterpene new for the genus Padina; phaeophytin and hidroxy-phaeophytin new for the family Dictyotaceae, and; mannitol first descri...
Nuts are part of a healthy diet such as Mediterranean diet. Benefits of nuts in reducing the risk of heart disease has been reasonably attributed to their composition of vitamins, minerals, unsaturated fatty acids, fiber and phytochemicals such as polyphenols, tocopherols, squalene and phytosterols. More than 75% of total fatty acids of nuts are unsaturated. αtocopherol is the main tocopherol i...
An understanding of gas transport in unsaturated media is important for evaluation of soil aeration or movement of O 2 from the atmosphere to the soil. Soil aeration is critical for plant root growth because roots generally cannot get enough O 2 from leaves. Evaluation of gas movement is also important for estimating transport of volatile and semivolatile organic compounds from contaminated sit...
We have developed a new spectroscopic system for detecting carbon-carbon bond formation by fluorescence to enhance high-throughput catalyst screening and rapid characterization of catalysts on a small scale. Fluorogenic substrates composed of a fluorophore possessing an amino group are readily prepared as amides of alpha,beta-unsaturated carbonyl compounds and generally exhibit low fluorescence...
Increasing prevalence of allergic diseases with an inadequate variety of treatment drives forward search for new alternative drugs. Fatty acids, abundant in nature, are regarded as important bioactive compounds and powerful nutrients playing an important role in lipid homeostasis and inflammation. Phytochemical study on Typhonium blumei Nicolson and Sivadasan (Araceae), a folk anti-cancer and a...
The hexane extract of the flowers of Rheum ribes L. which was collected from north-western Iran,was obtained by Soxhlet apparatus and the essential oil composition was obtained by hydro distillationand analyzed by using GC-GC/MS. The extract from the flowers was characterized by a high amountof unsaturated fatty acids (UFA) (66.0%) and some of long chain hydrocarbon compounds. The maincomponent...
The asymmetric hydrogenation of prochiral unsaturated compounds, such as alkenes, ketones, and imines, is one of the most efficient and straightforward methods for the preparation of optically active compounds. This method uses dihydrogen and small amounts of chiral transition metal complexes and is now recognized as economical, operationally simple, and environmentally friendly. It is frequent...
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