Pyrones

Pyrones

 

ketopyrans, heterocyclic compounds, oxo derivatives of pyrans. The simplest pyrones are α-pyrone, or coumalin, a colorless liquid with the odor of new-mown hay (boiling point, 206°-209°C), and γ-pyrone, colorless crystals (melting point, 31°–32°C).

Pyrones are highly reactive. For example, they react with ammonia and primary amines and are reduced readily; α-pyrone enters into the Diels-Alder reaction. Pyrones may be produced by decarboxylation of their derivatives, pyronecarboxylic acids (coumalic and chelidonic acids, respectively). Pyrone derivatives are widespread in nature. Tonka beans contain benzo-α-pyrone, or coumarin; opium contains meconic acid; and celandine sap contains chelidonic acid. Certain plant pigments are γ-pyrone derivatives.

References in periodicals archive ?
Kava pyrones and resin: studies on GABAA, GABAB and benzodiazepine binding sites in rodent brain.
Chemical studies carried out on Brazilian Piperaceae species have revealed the occurrence of pyrones, lignoids and chromenes besides various amides bearing isobutyl, pyrrolidine, dihydropyridone and piperidine moieties (Parmar et al.
However, basidiomes may also contain high concentrations of toxins, such as phenols, pyrones, and heterocyclic nitrogen complexes.
Pyrolysis rearranges guaiacols, catechols, syringols, vanillins, furancarboxaldehydes, isoeugenol, pyrones, acetic acid, formic acid, and other carboxylic acids (Piskorz et al.
Tawata, Essential oils, kava pyrones and phenolic compounds from leaves and rhizomes of Alpinia zerumbet (Pers.
25 M NaOH neutralises total acidity (carboxyl, lactones, phenols, carbonyls, and any other acidic species), and HCl neutralises all basic groups including ketones, pyrones, and chromens (Boehm 1994; Chun et al.
Neutralization with hydrochloric acid characterizes the amount of surface basic groups that are, for example, pyrones and chromenes.
Preparations marketed for human consumption contain a mixture of components collectively known as kava pyrones (i.
The recommended dosage suggested by German Commission E, an herbal drug review panel, is 60 to 120 milligrams of kava pyrones per day.