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The methoxide anion, for example, is both a strong base and nucleophile because it is a methyl nucleophile, and is thus very much unhindered. tert -Butoxide , on the other hand, is a strong base, but a poor nucleophile, because of its three methyl groups hindering its approach to the carbon.
The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. An example of nucleophilic substitution is the hydrolysis of an alkyl bromide , R-Br under basic conditions, where the attacking nucleophile is hydroxyl ( OH − ) and the leaving group is bromide ( Br − ).
Helenalin, or (-)-4-Hydroxy-4a,8-dimethyl-3,3a,4a,7a,8,9,9a-octahydroazuleno[6,5-b]furan-2,5-dione, is a toxic sesquiterpene lactone which can be found in several plants such as Arnica montana and Arnica chamissonis Helenalin is responsible for the toxicity of the Arnica spp.
A hydroxide ion acting as a nucleophile in an S N 2 reaction, converting a haloalkane into an alcohol. In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ...
Normal LDL cholesterol levels are associated with the build-up of atherosclerotic plaques in our arteries even in those with so-called optimal risk factors by current standards: blood pressure ...
Cholesterol is tested to determine for "normal" or "desirable" levels if a person has a total cholesterol of 5.2 mmol/L or less (200 mg/dL), an HDL value of more than 1 mmol/L (40 mg/dL, "the higher, the better"), an LDL value of less than 2.6 mmol/L (100 mg/dL), and a triglycerides level of less than 1.7 mmol/L (150 mg/dL).
Studies show that one avocado a day can reduce levels of bad cholesterol. Mackerel. Mackerel is a fatty fish that is high in omega-3 fatty acids, Poston says. Grapefruit.
LDL cholesterol is the “bad” cholesterol that can increase the risk of heart disease and stroke when levels are too high. HDL cholesterol is “good” cholesterol and high levels of it can ...