Search results
Results from the WOW.Com Content Network
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.
In organic chemistry, the Bohlmann–Rahtz pyridine synthesis is a reaction that generates substituted pyridines in two steps, first a condensation reaction between an enamine and an ethynylketone to form an aminodiene intermediate, which after heat-induced E/Z isomerization undergoes a cyclodehydration to yield 2,3,6-trisubstituted pyridines.
Pyrrole is an extremely weak base for an amine, with a conjugate acid pK a of −3.8. The most thermodynamically stable pyrrolium cation (C 4 H 6 N +) is formed by protonation at the 2 position. Substitution of pyrrole with alkyl substituents provides a more basic molecule—for example, tetramethylpyrrole has a conjugate acid pK a of +3.7.
Reduction of pyridine to piperidine with Raney nickel. Piperidine is produced by hydrogenation of pyridine with a nickel-, cobalt-, or ruthenium-based catalyst at elevated temperatures. [100] The hydrogenation of pyridine to piperidine releases 193.8 kJ/mol, [101] which is slightly less than the energy of the hydrogenation of benzene (205.3 kJ ...
The Chichibabin pyridine synthesis (/ ˈ tʃ iː tʃ iː ˌ b eɪ b iː n /) is a method for synthesizing pyridine rings. The reaction involves the condensation reaction of aldehydes, ketones, α,β-Unsaturated carbonyl compounds, or any combination of the above, with ammonia. [1] It was reported by Aleksei Chichibabin in 1924.
Polypyrrole Pyrrole can be polymerised electrochemically. [1] Polypyrrole (PPy) is an organic polymer obtained by oxidative polymerization of pyrrole. It is a solid with the formula H(C 4 H 2 NH) n H. It is an intrinsically conducting polymer, used in electronics, optical, biological and medical fields. [2] [3]
The Knorr pyrrole synthesis is a widely used chemical reaction that synthesizes substituted pyrroles (3). [ 1 ] [ 2 ] [ 3 ] The method involves the reaction of an α- amino - ketone (1) and a compound containing an electron-withdrawing group (e.g. an ester as shown) α to a carbonyl group (2) .
This lone pair is responsible for the basicity of these nitrogenous bases, similar to the nitrogen atom in amines. In these compounds, the nitrogen atom is not connected to a hydrogen atom. Examples of basic aromatic rings are pyridine or quinoline. Several rings contain basic as well as non-basic nitrogen atoms, e.g., imidazole and purine.