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The health effects of coffee include various possible health benefits and health risks. [ 1 ] A 2017 umbrella review of meta-analyses found that drinking coffee is generally safe within usual levels of intake and is more likely to improve health outcomes than to cause harm at doses of 3 or 4 cups of coffee daily.
Halogenation of benzene where X is the halogen, catalyst represents the catalyst (if needed) and HX represents the protonated base. A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid is required as a catalyst.
The chemical complexity of coffee is emerging, especially due to observed physiological effects which cannot be related only to the presence of caffeine. Moreover, coffee contains an exceptionally substantial amount of antioxidants such as chlorogenic acids, hydroxycinnamic acids, caffeine and Maillard reaction products, such as melanoidins. [3]
A new study found that drinking certain amounts of caffeinated coffee and tea was linked to a decreased risk for head and neck ... will have any other side effects or impacts on health overall and ...
Coffee drinkers, in particular, had the lowest risk — a nearly 50% reduction — while people who got the 200 to 300 milligrams of caffeine from tea or a mix of both beverages were about 40% ...
The overall reaction mechanism, denoted by the Hughes–Ingold mechanistic symbol S E Ar, [3] begins with the aromatic ring attacking the electrophile E + (2a). This step leads to the formation of a positively charged and delocalized cyclohexadienyl cation, also known as an arenium ion, Wheland intermediate, or arene σ-complex (2b).
Risk was reduced by more than 48% for coffee drinkers, specifically. Those who drank a moderate amount of any caffeine were nearly 41% less likely to develop cardiometabolic diseases.
Aside from these effects, there is often also a steric effect, due to increased steric hindrance at the ortho position but not the para position, leading to a larger amount of the para product. The effect is illustrated for electrophilic aromatic substitutions with alkyl substituents of differing steric demand for electrophilic aromatic ...