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With secondary amines and not primary amines the Zincke reaction takes on a different shape forming so-called Zincke aldehydes in which the pyridine ring is ring-opened with the terminal iminium group hydrolyzed to an aldehyde: [4] Zincke aldehydes. This variation has been applied in the synthesis of novel indoles: [11] Zincke aldehydes Kearney ...
It is the conjugate acid of pyridine. Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines. They are prepared by treating pyridine with acids. [3] As pyridine is often used as an organic base in chemical reactions, pyridinium salts are produced in many acid-base reactions.
Pyridinium perbromide (also called pyridinium bromide perbromide, pyridine hydrobromide perbromide, or pyridinium tribromide) is an organic chemical composed of a pyridinium cation and a tribromide anion. It can also be considered as a complex containing pyridinium bromide—the salt of pyridine and hydrogen bromide—with an added bromine (Br ...
[106] [107] One example is the sulfur trioxide pyridine complex (melting point 175 °C), which is a sulfation agent used to convert alcohols to sulfate esters. Pyridine-borane (C 5 H 5 NBH 3, melting point 10–11 °C) is a mild reducing agent. structure of the Crabtree's catalyst. Transition metal pyridine complexes are numerous.
Compared to benzene, the rate of electrophilic substitution on pyridine is much slower, due to the higher electronegativity of the nitrogen atom. Additionally, the nitrogen in pyridine easily gets a positive charge either by protonation (from nitration or sulfonation) or Lewis acids (such as AlCl 3) used to catalyze the reaction. This makes the ...
Hantzsch dihydropyridine synthesis, Hantzsch pyridine synthesis; Hantzsch pyridine synthesis, Gattermann–Skita synthesis, Guareschi–Thorpe condensation, Knoevenagel–Fries modification; Hantzsch–Collidin synthesis; Harries ozonolysis; Haworth methylation; Haworth Synthesis; Hay coupling; Hayashi rearrangement; Heck reaction; Hegedus ...
Simple aromatic rings can be heterocyclic if they contain non-carbon ring atoms, for example, oxygen, nitrogen, or sulfur. They can be monocyclic as in benzene, bicyclic as in naphthalene, or polycyclic as in anthracene. Simple monocyclic aromatic rings are usually five-membered rings like pyrrole or six-membered rings like pyridine.
The molecule consists of a pyridine ring with a nitrile group attached to the 3-position. A colorless solid, it is produced by ammoxidation of 3-methylpyridine: [2] H 3 CC 5 H 4 N + NH 3 + 1.5 O 2 → NCC 5 H 4 N + 3 H 2 O. Nicotinonitrile is a precursor to the vitamin niacin. [3]