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 ?
Phytochemical investigations carried out on Piper species have revealed the presence of several different classes of compounds, including alkaloids, amides, pyrones, propenylphenols, lignans, neolignans, terpenes, steroids, kawapyrones, piperolides, chal-cones and dihydrochalcones, flavones and flavanones (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.
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.
Kava, for example, is useful as an anxiolytic and mild tranquilizer in doses ranging from 60 to 120 mg of ava pyrones daily (equivalent to 1.
Toxicity of kava pyrones, drug safety and precautions - a case study.
Researchers have identified several pharmacologically active Kava pyrones, which have a primarily anxiolytic effect (e.
Apparently the distribution of the individual Kava pyrones in the different extracts is about equal, wich was obvious from the early findings by Hansel and Lazar (1985).
The causality assessment was done by the BfArM (BfArM 2002) and the MCA (MCA 2002): - not probable; 0 not assessable; + possible; ++ probable; +++ very probable; LTX--liver transplantation; Ci--cirrhosis of the liver Patient Age Sex Duration of Kava- (years) therapy pyrones (months) (mg/d) 1 39 f 3 210 2 69 f 24 up to 210 3 50 f 1.
Kava pyrones have been sold in Germany as OTC anxiolytics until June 2002, when all preparations with a kava pyrone content of more than [10.
Key words: kava pyrones, anxiolytics, adverse drug reaction, hepatotoxicity, risk evaluation
Boonen G, Haberlein H (1998) Influence of genuine kava pyrone enatiomers on the GAB[A.