Search results
Results from the WOW.Com Content Network
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.
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.
In a letter to Angewandte Chemie, the German chemist Manfred Christl [14] pointed out not only that the alleged new chemistry was in fact 100-year-old Zincke chemistry but also that the proposed structure for the reaction product was not the 12 membered ring but the 6 membered pyridinium salt (structure 2).
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 ...
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.
In its chemical structure and functions, the Cornforth reagent is closely related to other pyridinium salts of hexavalent chromium oxide, such as pyridinium chlorochromate [PyH][CrO 3 Cl] and to pyridine complexes such as the Collins reagent, CrO 3 ·2Py in dichloromethane and the Sarret reagent, CrO 3 ·2Py in pyridine. [4]
Digital banking opens up more competitive rates and fewer fees than your neighborhood brick-and-mortar bank, and robust apps make it easy to keep an eye on your balance, manage money among ...
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 ...