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4-Pyrone (γ-pyrone or pyran-4-one) is an unsaturated cyclic chemical compound with the molecular formula C 5 H 4 O 2.It is isomeric with 2-pyrone. Preparation [ edit ]
4H-Pyran was first isolated and characterized in 1962 via pyrolysis of 2-acetoxy-3,4-dihydro-2H-pyran. [1] It was found to be unstable, particularly in the presence of air. 4 H -pyran easily disproportionates to the corresponding dihydropyran and the pyrylium ion, which is easily hydrolyzed in aqueous medium.
Oxanes are the class of hexic cyclic ether rings with tetrahydropyran as the root chemical. Oxanes have one or more carbon atoms replaced with an oxygen atom. [8] The IUPAC preferred name for tetrahydropyran is now oxane. [9] Oxane is also the brand name for cis-2-methyl-4-propyl-1,3-oxathiane, a commercial fragrance. [10]
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. [1] [2] Ion associates are classified, according to the number of ions that associate with each other, as ion pairs, ion triplets, etc. Ion pairs are also classified according to the nature of the interaction as contact, solvent-shared or ...
The use of the prefixes ortho, meta and para to distinguish isomers of disubstituted aromatic rings starts with Wilhelm Körner in 1867, although he applied the ortho prefix to a 1,4-isomer and the meta prefix to a 1,2-isomer.
Benzopyran is a polycyclic organic compound that results from the fusion of a benzene ring to a heterocyclic pyran ring.. According to current IUPAC nomenclature, the name chromene used in previous recommendations is retained; however, systematic ‘benzo’ names, for example 2H-1-benzopyran, are preferred IUPAC names for chromene, isochromene, chromane, isochromane, and their chalcogen ...
The nitrogen (N)-containing aromatic rings can be separated into basic aromatic rings that are easily protonated, and form aromatic cations and salts (e.g., pyridinium), and non-basic aromatic rings. In the basic aromatic rings , the lone pair of electrons is not part of the aromatic system and extends in the plane of the ring.
Thiopyran is a heterocyclic compound with the chemical formula C 5 H 6 S. [1] It has two isomers, 2H-thiopyran and 4H-thiopyran, which differ by the location of double bonds. Thiopyrans are analogous to pyrans in which the oxygen atoms have been replaced by sulfur atoms.