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Its salts are often insoluble in the organic solvent, so precipitation of the pyridinium leaving group complex is an indication of the progress of the reaction. Pyridinium cations are aromatic, as determined through Hückel's rule. [4] They are isoelectronic with benzene.
Containing a pyridinium ion, pyridinium chloride has a pK a of approximately 5, slightly more acidic than that of typical amines. This is due to the hybridization of the nitrogen: the nitrogen is sp 2 hybridized and more electronegative than those nitrogens in ammonium cations, which are sp 3 hybridized. Hence they are stronger acids than ...
Properties Chemical formula. C 12 H 13 N O 3 S: ... Pyridinium p-toluenesulfonate (PPTS) is a colourless solid salt of pyridine and p-toluenesulfonic acid.
The second family of reagents are salts, featuring the pyridinium cation (C 5 H 5 NH +). pyridinium dichromate (PDC) is the pyridium salt of dichromate, [Cr 2 O 7] 2-. pyridinium chlorochromate (PCC) is the pyridinium salt of [CrO 3 Cl] −. These salts are less reactive, more easily handled, and more selective than Collins reagent in ...
Pyridinium chlorochromate in a vial. Pyridinium chlorochromate (PCC) is a yellow-orange salt with the formula [C 5 H 5 NH] + [CrO 3 Cl] −. It is a reagent in organic synthesis used primarily for oxidation of alcohols to form carbonyls. A variety of related compounds are known with similar reactivity.
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 ...
The Cornforth reagent (pyridinium dichromate or PDC) is a pyridinium salt of dichromate with the chemical formula [C 5 H 5 NH] 2 [Cr 2 O 7].This compound is named after the Australian-British chemist Sir John Warcup Cornforth (b. 1917) who introduced it in 1962.
The reaction of pyridine with bromomethyl ketones gives the related pyridinium salt, wherein the methylene group is highly acidic. This species undergoes a Michael-like addition to α,β-unsaturated carbonyls in the presence of ammonium acetate to undergo ring closure and formation of the targeted substituted pyridine as well as pyridinium ...