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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
The first reaction is the formation of the N-2,4-dinitrophenyl-pyridinium salt (2). This salt is typically isolated and purified by recrystallization. The formation of the DNP-pyridinium salt. Upon heating a primary amine with the N-2,4-dinitrophenyl-pyridinium salt (2), the addition of the amine leads to the opening of the pyridinium ring.
Pyridine-N-oxide is the heterocyclic compound with the formula C 5 H 5 NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis. [1]
In the case of nitration of benzene, the reaction is conducted at a warm temperature, not exceeding 50 °C. [6] The process is one example of electrophilic aromatic substitution, which involves the attack by the electron-rich benzene ring: Alternative mechanisms have also been proposed, including one involving single electron transfer (SET). [7 ...
A workup step with acid is included to ensure formation of 2-aminopyridine. Reaction progress can be measured by the formation of hydrogen gas and red color from σ-adduct formation. [3] Sodium amide is a handy reagent for the Chichibabin reaction but handling it can be dangerous and caution is advised. [4] σ-adduct (Meisenheimer adduct) formation
Molecular mechanism of ammonium oxidation by AOB Ammonia oxidation in autotrophic nitrification is a complex process that requires several enzymes as well as oxygen as a reactant. The key enzymes necessary for releasing energy during oxidation of ammonia to nitrite are ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO).
At least five significant pathways have been proposed for the Hantzch reaction synthesis of 1,4-dihydropyridine. Low yield and unexpected products may arise under varying reactants and reaction conditions. Previous studies have tested the reactions of preformed intermediates to determine the most likely mechanism and design successful syntheses ...
The Boger pyridine synthesis is a cycloaddition approach to the formation of pyridines named after its inventor Dale L. Boger, who first reported it in 1981. [1] The reaction is a form of inverse-electron demand Diels-Alder reaction in which an enamine reacts with a 1,2,4-triazine to form the pyridine nucleus.