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Pyridine is a basic heterocyclic organic compound with the chemical formula C 5 H 5 N. It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom (=N−). It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish
Even with no catalysts, the nitrogen atom, being electronegative, can hold the negative charge by itself. Another way is to do an oxidation before the electrophilic substitution. This makes pyridine N-oxide, which due to the negative oxygen atom, makes the reaction faster than pyridine, and even benzene. The oxide then can be reduced to the ...
This reaction is similar to nucleophilic aliphatic substitution where the reactant is a nucleophile rather than an electrophile. The four possible electrophilic aliphatic substitution reaction mechanisms are S E 1, S E 2(front), S E 2(back) and S E i (Substitution Electrophilic), which are also similar to the nucleophile counterparts S N 1 and ...
The reaction proceeds through generation of an acylium center. The reaction is completed by deprotonation of the arenium ion by AlCl 4 −, regenerating the AlCl 3 catalyst. However, in contrast to the truly catalytic alkylation reaction, the formed ketone is a moderate Lewis base, which forms a complex with the strong Lewis acid aluminum ...
Substitution reactions in organic chemistry are classified either as electrophilic or nucleophilic depending upon the reagent involved, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical, and whether the substrate is aliphatic or aromatic. Detailed understanding of a reaction type helps to ...
This reaction occurs in a similar way to the addition reaction but has an extra step in which the OSO 3 H group is replaced by an OH group, forming an alcohol: C 2 H 4 + H 2 O → C 2 H 5 OH. As can be seen, the H 2 SO 4 does take part in the overall reaction, however it remains unchanged so is classified as a catalyst. This is the reaction in ...
The direct amination of pyridine with sodium amide can take place in liquid ammonia or an aprotic solvent such as xylene is commonly used. Following the addition elimination mechanism first a nucleophilic NH 2 − is added while a hydride (H −) is leaving. The reaction formally is a nucleophilic substitution of hydrogen S N H.
The Schiff base is an electrophile which reacts in a second step in an electrophilic addition with an enol formed from a carbonyl compound containing an acidic alpha-proton. The Mannich reaction is a condensation reaction. [4]: 140 In the Mannich reaction, primary or secondary amines or ammonia react with formaldehyde to form a Schiff base ...