Reductones
Reductones are organic - chemical compounds that have two hydroxyl groups (“ enediols ”) on the two carbon atoms of a C = C double bond and also have a carbonyl group directly on the adjacent carbon atom . The double bond of these enediols is stabilized because of the conjugation with the carbonyl group; therefore, in the tautomeric equilibrium (" keto-enol tautomerism "), it is mainly the enediol form and not the keto form that is present. As vinylogous carboxylic acids , reductones are acidic.
The name goes back to Hans Karl August Simon von Euler-Chelpin , who discovered this class of substances in 1930. He heated glucose with sodium hydroxide solution and received a substance with the empirical formula C 3 H 4 O 3 , which had a strongly reducing effect. This substance is now known as hydroxypropanedial or hydroxymalonaldehyde .
Structure and tautomerism
| Tartronaldehyde (triosereductone) or hydroxypropanedial |
Ascorbic acid (vitamin C) |
Reductic acid (2,3-dihydroxy-2-cyclopentenone) |
Acetylformoin |
|---|---|---|---|
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 |
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| (on the left the enediol form, on the right the hydroxypropandial) | (left the enediol form, right the cyclic hemiacetal) |
meaning
Both in nature and in food chemistry, reductones play an important role as antioxidants , thus protecting sensitive biomolecules from oxygen, hydroxyl radicals and other strongly oxidizing particles. However, if food is stored for a long time, it also destroys its odor and taste. They may also be involved in the browning of bread , coffee, and malt ; for acetylformoin occurrence is assigned as a reactive intermediate in browning reactions in the presence of glucose.
Individual evidence
- ↑ Entry on Reductones . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.R05224 Version: 2.3.3.
- ↑ a b Entry on reductones. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
- ↑ Wolfgang Legrum: Fragrances, between stench and fragrance . Springer Fachmedien, Wiesbaden 2015, ISBN 978-3-658-07309-1 , chap. Flavorings in foods , p. 115–117 , doi : 10.1007 / 978-3-658-07310-7_5 .