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The mesomeric effect as a result of p-orbital overlap (resonance) has absolutely no effect on this inductive effect, as the inductive effect has purely to do with the electronegativity of the atoms and their topology in the molecule (which atoms are connected to which). Specifically the inductive effect is the tendency for the substituents to ...
The effect of the substituent may change the rate-determining step (rds) in the mechanism of the reaction. A certain electronic effect may accelerate a certain step so that it is no longer the rds. [14] [non-primary source needed] [non-primary source needed] change in rate determining step. A change in the mechanism of a reaction also results ...
However, another effect that plays a role is the +M effect which adds electron density back into the benzene ring (thus having the opposite effect of the -I effect but by a different mechanism). This is called the mesomeric effect (hence +M) and the result for fluorine is that the +M effect approximately cancels out the -I effect. The effect of ...
It is often said the resonance stability of phenol makes it a stronger acid than that of aliphatic alcohols such as ethanol (pK a = 10 vs. 16–18). However, a significant contribution is the greater electronegativity of the sp 2 alpha carbon in phenol compared to the sp 3 alpha carbon in aliphatic alcohols. [7]
Other structural factors that influence the magnitude of the acid dissociation constant include inductive effects, mesomeric effects, and hydrogen bonding. Hammett type equations have frequently been applied to the estimation of pK a. [3] [4] The quantitative behaviour of acids and bases in solution can be understood only if their pK a values ...
The reaction mechanism [2] begins with an imine condensation of a primary aromatic amine and formaldehyde. Once the imine is produced, it reacts with phenol in the presence of water to yield an α-aminobenzylphenol. An electron pushing mechanism for the Betti Reaction.
In a variation the reaction of phenols and beta-ketoesters and phosphorus pentoxide yields a chromone.This reaction is called Simonis chromone cyclization. [6] [7] The ketone in the ketoester is activated by P 2 O 5 for reaction with the phenol hydroxyl group first, the ester group in it is then activated for electrophilic attack of the arene.
In subsequent phase II reactions, these activated metabolites are conjugated with charged species such as glutathione, sulfate, glycine or glucuronic acid. These reactions are catalysed by a large group of broad-specificity transferases. UGT1A6 is a human gene encoding a phenol UDP glucuronosyltransferase active on simple phenols. [106]