| 单词 |
pyrone |
| 释义 |
pyrone Chem.|ˈpaɪərəʊn|
[ad. G. pyron (Haitinger & Lieben 1885, in Sitzungsber. d. österreichischen Akad. d. Wissensch. in Wien XCI. (Abt. ii.) 923): see pyro- and -one.]
Either of two unsaturated heterocyclic compounds, C5H4O2, which are mono-keto derivatives of the pyrans; spec. CH:CH·O·CH:CH·CO (γ- or 1, 4-pyrone), a colourless, basic, crystalline solid; also, any heterocyclic ketone or lactone containing the ring structure characteristic of either isomer. Freq. attrib., as pyrone ring.
1891Jrnl. Chem. Soc. LX. i. 458 The pyrone is almost insoluble in water or alkalis. Ibid. ii. 939 The conversion of α-pyrone into pyridine derivatives. 1913T. H. Pope tr. Molinari's Org. Chem. 626 Chelidonic acid,..which is found in celandine, loses CO2 giving comanic acid and pyrone. 1938G. H. Richter Textbk. Org. Chem. xxxi. 659 The pyrones are interesting also because the hetero oxygen atom is basic forming oxonium salts with strong acids. 1962K. Venkataraman in T. A. Geissman Chem. Flavonoid Compounds iv. 94 Isoflavones undergo hydrolysis with opening of the pyrone ring under mild conditions of alkali treatment. 1963L. F. & M. Fieser Topics in Org. Chem. ii. 103 α-Pyrone has the properties expected of a doubly unsaturated δ-lactone. Ibid. 104 Representative natural γ-pyrones are kojic acid, formed by bacterial fermentation of carbohydrates; maltol, isolated from the bark of the larch tree; and yangonin, from the roots of the kava shrub. 1972J. M. Tedder et al. Basic Org. Chem. IV. iii. 139 The reactivity of the carbonyl group is reduced so much by the conjugation..that the α-pyrone ring is much more stable towards alkali than the unsubstituted coumarin. |
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