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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 ...
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.
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.
Pyridine depresses the nervous system giving symptoms similar to intoxication with vapor concentrations of above 3600 ppm posing a greater health risk. [2] The effects may have a delayed onset of several hours and include dizziness, headache, lack of coordination, nausea, salivation, and loss of appetite.
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.
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.
In Honduras, the business-lending arm of the World Bank aligned itself with a key player in a land dispute that has left more than 130 people dead, including Gregorio Chávez, a preacher who went out to tend his garden one day and didn’t come back. In the last decade, the International Finance Corp.’s lending and influence has soared, even as it has embraced financing methods that shield ...
The pyridinium side-group of cephaloridine has unstable bonds to the core of the compound (in comparison with other cephalosporins). When this side-group leaves, the β-lactam ring is destabilized by intramolecular electron shifts. [13] Thus, the leaving group creates a reactive product.