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Pyridinium refers to the cation [C 5 H 5 NH] +. It is the conjugate acid of pyridine . Many related cations are known involving substituted pyridines, e.g. picolines, lutidines, collidines.
An ylide (/ ˈ ɪ l aɪ d /) [1] or ylid (/ ˈ ɪ l ɪ d /) is a neutral dipolar molecule containing a formally negatively charged atom (usually a carbanion) directly attached to a heteroatom with a formal positive charge (usually nitrogen, phosphorus or sulfur), and in which both atoms have full octets of electrons.
Radical disproportionation encompasses a group of reactions in organic chemistry in which two radicals react to form two different non-radical products. Radicals in chemistry are defined as reactive atoms or molecules that contain an unpaired electron or electrons in an open shell. The unpaired electrons can cause radicals to be unstable and ...
In organic synthesis, PPTS is used as a weakly acidic catalyst, providing an organic soluble source of pyridinium (C 5 H 5 NH +) ions.For example, PPTS is used to deprotect silyl ethers or tetrahydropyranyl ethers when a substrate is unstable to stronger acid catalysts.
Chlorine, for example, gives two chlorine radicals (Cl•) by irradiation with ultraviolet light. This process is used for chlorination of alkanes . Azo compounds (R- N =N-R') can be the precursor of two carbon -centered radicals (R• and R'•) and nitrogen gas upon heating and/or by irradiation.
For example, treatment of 1,3-diketone 14 with base in ethanol followed by ammonium acetate, acetic acid, the corresponding enone and a Lewis acid yields 3-acyltriarylpyridines of the form 15. These acyl pyridine are attractive intermediates because they have an electrophilic handle that allows for additional functionality to be incorporated ...
Radical theory is an obsolete scientific theory in chemistry describing the structure of organic compounds.The theory was pioneered by Justus von Liebig, Friedrich Wöhler and Auguste Laurent around 1830 and is not related to the modern understanding of free radicals.
Example radical: Structure of Hydrocarboxyl radical, lone electron indicated as single black dot. A radical is a molecule with an odd number of electrons, and is induced in a variety of ways, including ultraviolet radiation. A sun burn is largely due to radical formation from this radiation. The radical-pair, however, is not simply two radicals.