In organic chemistry, α‑lactone refers to a functional group, the smallest possible lactone. It is a family of unstable, three-membered heterocycles, containing an epoxide ring fused with a carbonyl group.
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| Names | |||
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| IUPAC name
Oxiran-2-one1
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| Preferred IUPAC name
Oxiranone | |||
| Identifiers | |||
3D model (JSmol)
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |||
| C2H2O2 | |||
| Molar mass | 58.036 g·mol−1 | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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The parent, acetolactone (α-acetolactone), is an organic compound with formula C
2H
2O
2, and has not been isolated in bulk. The compound was first described in 1997 as a transient species in mass spectrometry experiments.2
Generally, α‑lactones are produced by the cryogenic, photochemical decarboxylation of peroxymalonic anhydrides. Even at 77 K, the products rapidly polymerize or decarbonylate to ketones or aldehydes.3
An exception is bis(trifluoromethyl)acetolactone ((CF
3)
2C
2O
2), stabilized by its two trifluoromethyl groups. That compound has a half-life of 8 hours at 25 °C.4
Α-Thiolactones can be produced via oxygen transfer from a nitrone to a thioketene.5
References
References
- "Acetolactone". PubChem. National Center for Biotechnology Information.
- Detlef Schröder, Norman Goldberg, Waltraud Zummack, Helmut Schwarz, John C. Poutsma and Robert R. Squires (1997), Generation of α-acetolactone and the acetoxyl diradical •CH2COO• in the gas phase. International Journal of Mass Spectrometry and Ion Processes, volumes 165-166, November issue, pages 71-82. doi:10.1016/S0168-1176(97)00150-X
- Chapman, O. L.; Wojtkowski, P. W.; Adam, Waldemar; Rodriguez, O.; Rucktaeschel, R. (1972). "Photochemical transformations. XLIV. Cyclic peroxides. Synthesis and chemistry of .alpha.-lactones". Journal of the American Chemical Society. 94 (4): 1365–1367. Bibcode:1972JAChS..94.1365C. doi:10.1021/ja00759a060.
- Adam, Waldemar; Liu, Ju-Chao; Rodriguez, Oswaldo (1973). "Bis(trifluoromethyl)acetolactone, a Stable α-Lactone". The Journal of Organic Chemistry. 38 (12): 2269–2270. doi:10.1021/jo00952a047.
- Voss, J. (1979). "The chemistry of thio acid derivatives". In Patai, Saul (ed.). The Chemistry of Acid Derivatives. The Chemistry of Functional Groups, Supplement B. Vol. 1, Part 2. Chichester, WSX: Interscience (Wiley). p. 1038. ISBN 0 471 99611 4. LCCN 75-6913.

