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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 ...
Density (g cm-3) Boiling point (°C) K b ... Ethylene bromide: 2.18 133 6.43 9.974 –12.5 ... Acetic Anhydride: 139.0 [6] Ethylene Dichloride: 1.25
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 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 ...
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.
4-Dimethylaminopyridine (DMAP) is a derivative of pyridine with the chemical formula (CH 3) 2 NC 5 H 4 N. This white solid is of interest because it is more basic than pyridine, owing to the resonance stabilisation from the NMe 2 substituent.
The main use for phosphorus tribromide is for conversion of primary or secondary alcohols to alkyl bromides, [9] as described above.PBr 3 usually gives higher yields than hydrobromic acid, and it avoids problems of carbocation rearrangement- for example even neopentyl bromide can be made from the alcohol in 60% yield.
Methylpyridinium is prepared by treating pyridine with dimethylsulfate: [2]. C 5 H 5 N + (CH 3 O) 2 SO 2 → [C 5 H 5 NCH 3] + CH 3 OSO − 3. It is found in some coffee products. [3] It is not present in unroasted coffee beans, but is formed during roasting from its precursor chemical, trigonelline. [3]